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hush.c

/*
 * sh.c -- a prototype Bourne shell grammar parser
 *      Intended to follow the original Thompson and Ritchie
 *      "small and simple is beautiful" philosophy, which
 *      incidentally is a good match to today's BusyBox.
 *
 * Copyright (C) 2000,2001  Larry Doolittle  <larry@doolittle.boa.org>
 *
 * Credits:
 *      The parser routines proper are all original material, first
 *      written Dec 2000 and Jan 2001 by Larry Doolittle.
 *      The execution engine, the builtins, and much of the underlying
 *      support has been adapted from busybox-0.49pre's lash,
 *      which is Copyright (C) 2000 by Lineo, Inc., and
 *      written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>.
 *      That, in turn, is based in part on ladsh.c, by Michael K. Johnson and
 *      Erik W. Troan, which they placed in the public domain.  I don't know
 *      how much of the Johnson/Troan code has survived the repeated rewrites.
 * Other credits:
 *      simple_itoa() was lifted from boa-0.93.15
 *      b_addchr() derived from similar w_addchar function in glibc-2.2
 *      setup_redirect(), redirect_opt_num(), and big chunks of main()
 *        and many builtins derived from contributions by Erik Andersen
 *      miscellaneous bugfixes from Matt Kraai
 *
 * There are two big (and related) architecture differences between
 * this parser and the lash parser.  One is that this version is
 * actually designed from the ground up to understand nearly all
 * of the Bourne grammar.  The second, consequential change is that
 * the parser and input reader have been turned inside out.  Now,
 * the parser is in control, and asks for input as needed.  The old
 * way had the input reader in control, and it asked for parsing to
 * take place as needed.  The new way makes it much easier to properly
 * handle the recursion implicit in the various substitutions, especially
 * across continuation lines.
 *
 * Bash grammar not implemented: (how many of these were in original sh?)
 *      $@ (those sure look like weird quoting rules)
 *      $_
 *      ! negation operator for pipes
 *      &> and >& redirection of stdout+stderr
 *      Brace Expansion
 *      Tilde Expansion
 *      fancy forms of Parameter Expansion
 *      aliases
 *      Arithmetic Expansion
 *      <(list) and >(list) Process Substitution
 *      reserved words: case, esac, select, function
 *      Here Documents ( << word )
 *      Functions
 * Major bugs:
 *      job handling woefully incomplete and buggy
 *      reserved word execution woefully incomplete and buggy
 * to-do:
 *      port selected bugfixes from post-0.49 busybox lash - done?
 *      finish implementing reserved words: for, while, until, do, done
 *      change { and } from special chars to reserved words
 *      builtins: break, continue, eval, return, set, trap, ulimit
 *      test magic exec
 *      handle children going into background
 *      clean up recognition of null pipes
 *      check setting of global_argc and global_argv
 *      control-C handling, probably with longjmp
 *      follow IFS rules more precisely, including update semantics
 *      figure out what to do with backslash-newline
 *      explain why we use signal instead of sigaction
 *      propagate syntax errors, die on resource errors?
 *      continuation lines, both explicit and implicit - done?
 *      memory leak finding and plugging - done?
 *      more testing, especially quoting rules and redirection
 *      document how quoting rules not precisely followed for variable assignments
 *      maybe change map[] to use 2-bit entries
 *      (eventually) remove all the printf's
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#define __U_BOOT__
#ifdef __U_BOOT__
#include <malloc.h>         /* malloc, free, realloc*/
#include <linux/ctype.h>    /* isalpha, isdigit */
#include <common.h>        /* readline */
#include <hush.h>
#include <command.h>        /* find_cmd */
/*cmd_boot.c*/
extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);      /* do_bootd */
#endif
#ifndef __U_BOOT__
#include <ctype.h>     /* isalpha, isdigit */
#include <unistd.h>    /* getpid */
#include <stdlib.h>    /* getenv, atoi */
#include <string.h>    /* strchr */
#include <stdio.h>     /* popen etc. */
#include <glob.h>      /* glob, of course */
#include <stdarg.h>    /* va_list */
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>    /* should be pretty obvious */

#include <sys/stat.h>  /* ulimit */
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>

/* #include <dmalloc.h> */

#if 1
#include "busybox.h"
#include "cmdedit.h"
#else
#define applet_name "hush"
#include "standalone.h"
#define hush_main main
#undef CONFIG_FEATURE_SH_FANCY_PROMPT
#define BB_BANNER
#endif
#endif
#define SPECIAL_VAR_SYMBOL 03
#ifndef __U_BOOT__
#define FLAG_EXIT_FROM_LOOP 1
#define FLAG_PARSE_SEMICOLON (1 << 1)           /* symbol ';' is special for parser */
#define FLAG_REPARSING       (1 << 2)           /* >= 2nd pass */

#endif

#ifdef __U_BOOT__
DECLARE_GLOBAL_DATA_PTR;

#define EXIT_SUCCESS 0
#define EOF -1
#define syntax() syntax_err()
#define xstrdup strdup
#define error_msg printf
#else
typedef enum {
      REDIRECT_INPUT     = 1,
      REDIRECT_OVERWRITE = 2,
      REDIRECT_APPEND    = 3,
      REDIRECT_HEREIS    = 4,
      REDIRECT_IO        = 5
} redir_type;

/* The descrip member of this structure is only used to make debugging
 * output pretty */
struct {int mode; int default_fd; char *descrip;} redir_table[] = {
      { 0,                         0, "()" },
      { O_RDONLY,                  0, "<"  },
      { O_CREAT|O_TRUNC|O_WRONLY,  1, ">"  },
      { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
      { O_RDONLY,                 -1, "<<" },
      { O_RDWR,                    1, "<>" }
};
#endif

typedef enum {
      PIPE_SEQ = 1,
      PIPE_AND = 2,
      PIPE_OR  = 3,
      PIPE_BG  = 4,
} pipe_style;

/* might eventually control execution */
typedef enum {
      RES_NONE  = 0,
      RES_IF    = 1,
      RES_THEN  = 2,
      RES_ELIF  = 3,
      RES_ELSE  = 4,
      RES_FI    = 5,
      RES_FOR   = 6,
      RES_WHILE = 7,
      RES_UNTIL = 8,
      RES_DO    = 9,
      RES_DONE  = 10,
      RES_XXXX  = 11,
      RES_IN    = 12,
      RES_SNTX  = 13
} reserved_style;
#define FLAG_END   (1<<RES_NONE)
#define FLAG_IF    (1<<RES_IF)
#define FLAG_THEN  (1<<RES_THEN)
#define FLAG_ELIF  (1<<RES_ELIF)
#define FLAG_ELSE  (1<<RES_ELSE)
#define FLAG_FI    (1<<RES_FI)
#define FLAG_FOR   (1<<RES_FOR)
#define FLAG_WHILE (1<<RES_WHILE)
#define FLAG_UNTIL (1<<RES_UNTIL)
#define FLAG_DO    (1<<RES_DO)
#define FLAG_DONE  (1<<RES_DONE)
#define FLAG_IN    (1<<RES_IN)
#define FLAG_START (1<<RES_XXXX)

/* This holds pointers to the various results of parsing */
struct p_context {
      struct child_prog *child;
      struct pipe *list_head;
      struct pipe *pipe;
#ifndef __U_BOOT__
      struct redir_struct *pending_redirect;
#endif
      reserved_style w;
      int old_flag;                       /* for figuring out valid reserved words */
      struct p_context *stack;
      int type;               /* define type of parser : ";$" common or special symbol */
      /* How about quoting status? */
};

#ifndef __U_BOOT__
struct redir_struct {
      redir_type type;              /* type of redirection */
      int fd;                                   /* file descriptor being redirected */
      int dup;                            /* -1, or file descriptor being duplicated */
      struct redir_struct *next;    /* pointer to the next redirect in the list */
      glob_t word;                        /* *word.gl_pathv is the filename */
};
#endif

struct child_prog {
#ifndef __U_BOOT__
      pid_t pid;                          /* 0 if exited */
#endif
      char **argv;                        /* program name and arguments */
#ifdef __U_BOOT__
      int    argc;                            /* number of program arguments */
#endif
      struct pipe *group;                 /* if non-NULL, first in group or subshell */
#ifndef __U_BOOT__
      int subshell;                       /* flag, non-zero if group must be forked */
      struct redir_struct *redirects;     /* I/O redirections */
      glob_t glob_result;                 /* result of parameter globbing */
      int is_stopped;                     /* is the program currently running? */
      struct pipe *family;          /* pointer back to the child's parent pipe */
#endif
      int sp;                       /* number of SPECIAL_VAR_SYMBOL */
      int type;
};

struct pipe {
#ifndef __U_BOOT__
      int jobid;                          /* job number */
#endif
      int num_progs;                      /* total number of programs in job */
#ifndef __U_BOOT__
      int running_progs;                  /* number of programs running */
      char *text;                         /* name of job */
      char *cmdbuf;                       /* buffer various argv's point into */
      pid_t pgrp;                         /* process group ID for the job */
#endif
      struct child_prog *progs;     /* array of commands in pipe */
      struct pipe *next;                  /* to track background commands */
#ifndef __U_BOOT__
      int stopped_progs;                  /* number of programs alive, but stopped */
      int job_context;              /* bitmask defining current context */
#endif
      pipe_style followup;          /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
      reserved_style r_mode;        /* supports if, for, while, until */
};

#ifndef __U_BOOT__
struct close_me {
      int fd;
      struct close_me *next;
};
#endif

struct variables {
      char *name;
      char *value;
      int flg_export;
      int flg_read_only;
      struct variables *next;
};

/* globals, connect us to the outside world
 * the first three support $?, $#, and $1 */
#ifndef __U_BOOT__
char **global_argv;
unsigned int global_argc;
#endif
unsigned int last_return_code;
int nesting_level;
#ifndef __U_BOOT__
extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
#endif

/* "globals" within this file */
static uchar *ifs;
static char map[256];
#ifndef __U_BOOT__
static int fake_mode;
static int interactive;
static struct close_me *close_me_head;
static const char *cwd;
static struct pipe *job_list;
static unsigned int last_bg_pid;
static unsigned int last_jobid;
static unsigned int shell_terminal;
static char *PS1;
static char *PS2;
struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
struct variables *top_vars = &shell_ver;
#else
static int flag_repeat = 0;
static int do_repeat = 0;
static struct variables *top_vars = NULL ;
#endif /*__U_BOOT__ */

#define B_CHUNK (100)
#define B_NOSPAC 1

typedef struct {
      char *data;
      int length;
      int maxlen;
      int quote;
      int nonnull;
} o_string;
#define NULL_O_STRING {NULL,0,0,0,0}
/* used for initialization:
      o_string foo = NULL_O_STRING; */

/* I can almost use ordinary FILE *.  Is open_memstream() universally
 * available?  Where is it documented? */
struct in_str {
      const char *p;
#ifndef __U_BOOT__
      char peek_buf[2];
#endif
      int __promptme;
      int promptmode;
#ifndef __U_BOOT__
      FILE *file;
#endif
      int (*get) (struct in_str *);
      int (*peek) (struct in_str *);
};
#define b_getch(input) ((input)->get(input))
#define b_peek(input) ((input)->peek(input))

#ifndef __U_BOOT__
#define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"

struct built_in_command {
      char *cmd;                          /* name */
      char *descr;                        /* description */
      int (*function) (struct child_prog *);    /* function ptr */
};
#endif

/* define DEBUG_SHELL for debugging output (obviously ;-)) */
#if 0
#define DEBUG_SHELL
#endif

/* This should be in utility.c */
#ifdef DEBUG_SHELL
#ifndef __U_BOOT__
static void debug_printf(const char *format, ...)
{
      va_list args;
      va_start(args, format);
      vfprintf(stderr, format, args);
      va_end(args);
}
#else
#define debug_printf(fmt,args...)   printf (fmt ,##args)
#endif
#else
static inline void debug_printf(const char *format, ...) { }
#endif
#define final_printf debug_printf

#ifdef __U_BOOT__
static void syntax_err(void) {
       printf("syntax error\n");
}
#else
static void __syntax(char *file, int line) {
      error_msg("syntax error %s:%d", file, line);
}
#define syntax() __syntax(__FILE__, __LINE__)
#endif

#ifdef __U_BOOT__
static void *xmalloc(size_t size);
static void *xrealloc(void *ptr, size_t size);
#else
/* Index of subroutines: */
/*   function prototypes for builtins */
static int builtin_cd(struct child_prog *child);
static int builtin_env(struct child_prog *child);
static int builtin_eval(struct child_prog *child);
static int builtin_exec(struct child_prog *child);
static int builtin_exit(struct child_prog *child);
static int builtin_export(struct child_prog *child);
static int builtin_fg_bg(struct child_prog *child);
static int builtin_help(struct child_prog *child);
static int builtin_jobs(struct child_prog *child);
static int builtin_pwd(struct child_prog *child);
static int builtin_read(struct child_prog *child);
static int builtin_set(struct child_prog *child);
static int builtin_shift(struct child_prog *child);
static int builtin_source(struct child_prog *child);
static int builtin_umask(struct child_prog *child);
static int builtin_unset(struct child_prog *child);
static int builtin_not_written(struct child_prog *child);
#endif
/*   o_string manipulation: */
static int b_check_space(o_string *o, int len);
static int b_addchr(o_string *o, int ch);
static void b_reset(o_string *o);
static int b_addqchr(o_string *o, int ch, int quote);
#ifndef __U_BOOT__
static int b_adduint(o_string *o, unsigned int i);
#endif
/*  in_str manipulations: */
static int static_get(struct in_str *i);
static int static_peek(struct in_str *i);
static int file_get(struct in_str *i);
static int file_peek(struct in_str *i);
#ifndef __U_BOOT__
static void setup_file_in_str(struct in_str *i, FILE *f);
#else
static void setup_file_in_str(struct in_str *i);
#endif
static void setup_string_in_str(struct in_str *i, const char *s);
#ifndef __U_BOOT__
/*  close_me manipulations: */
static void mark_open(int fd);
static void mark_closed(int fd);
static void close_all(void);
#endif
/*  "run" the final data structures: */
static char *indenter(int i);
static int free_pipe_list(struct pipe *head, int indent);
static int free_pipe(struct pipe *pi, int indent);
/*  really run the final data structures: */
#ifndef __U_BOOT__
static int setup_redirects(struct child_prog *prog, int squirrel[]);
#endif
static int run_list_real(struct pipe *pi);
#ifndef __U_BOOT__
static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
#endif
static int run_pipe_real(struct pipe *pi);
/*   extended glob support: */
#ifndef __U_BOOT__
static int globhack(const char *src, int flags, glob_t *pglob);
static int glob_needed(const char *s);
static int xglob(o_string *dest, int flags, glob_t *pglob);
#endif
/*   variable assignment: */
static int is_assignment(const char *s);
/*   data structure manipulation: */
#ifndef __U_BOOT__
static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
#endif
static void initialize_context(struct p_context *ctx);
static int done_word(o_string *dest, struct p_context *ctx);
static int done_command(struct p_context *ctx);
static int done_pipe(struct p_context *ctx, pipe_style type);
/*   primary string parsing: */
#ifndef __U_BOOT__
static int redirect_dup_num(struct in_str *input);
static int redirect_opt_num(o_string *o);
static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
#endif
static char *lookup_param(char *src);
static char *make_string(char **inp);
static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
#ifndef __U_BOOT__
static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
#endif
static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
/*   setup: */
static int parse_stream_outer(struct in_str *inp, int flag);
#ifndef __U_BOOT__
static int parse_string_outer(const char *s, int flag);
static int parse_file_outer(FILE *f);
#endif
#ifndef __U_BOOT__
/*   job management: */
static int checkjobs(struct pipe* fg_pipe);
static void insert_bg_job(struct pipe *pi);
static void remove_bg_job(struct pipe *pi);
#endif
/*     local variable support */
static char **make_list_in(char **inp, char *name);
static char *insert_var_value(char *inp);
static char *get_local_var(const char *var);

#ifndef __U_BOOT__
/* Table of built-in functions.  They can be forked or not, depending on
 * context: within pipes, they fork.  As simple commands, they do not.
 * When used in non-forking context, they can change global variables
 * in the parent shell process.  If forked, of course they can not.
 * For example, 'unset foo | whatever' will parse and run, but foo will
 * still be set at the end. */
static struct built_in_command bltins[] = {
      {"bg", "Resume a job in the background", builtin_fg_bg},
      {"break", "Exit for, while or until loop", builtin_not_written},
      {"cd", "Change working directory", builtin_cd},
      {"continue", "Continue for, while or until loop", builtin_not_written},
      {"env", "Print all environment variables", builtin_env},
      {"eval", "Construct and run shell command", builtin_eval},
      {"exec", "Exec command, replacing this shell with the exec'd process",
            builtin_exec},
      {"exit", "Exit from shell()", builtin_exit},
      {"export", "Set environment variable", builtin_export},
      {"fg", "Bring job into the foreground", builtin_fg_bg},
      {"jobs", "Lists the active jobs", builtin_jobs},
      {"pwd", "Print current directory", builtin_pwd},
      {"read", "Input environment variable", builtin_read},
      {"return", "Return from a function", builtin_not_written},
      {"set", "Set/unset shell local variables", builtin_set},
      {"shift", "Shift positional parameters", builtin_shift},
      {"trap", "Trap signals", builtin_not_written},
      {"ulimit","Controls resource limits", builtin_not_written},
      {"umask","Sets file creation mask", builtin_umask},
      {"unset", "Unset environment variable", builtin_unset},
      {".", "Source-in and run commands in a file", builtin_source},
      {"help", "List shell built-in commands", builtin_help},
      {NULL, NULL, NULL}
};

static const char *set_cwd(void)
{
      if(cwd==unknown)
            cwd = NULL;     /* xgetcwd(arg) called free(arg) */
      cwd = xgetcwd((char *)cwd);
      if (!cwd)
            cwd = unknown;
      return cwd;
}

/* built-in 'eval' handler */
static int builtin_eval(struct child_prog *child)
{
      char *str = NULL;
      int rcode = EXIT_SUCCESS;

      if (child->argv[1]) {
            str = make_string(child->argv + 1);
            parse_string_outer(str, FLAG_EXIT_FROM_LOOP |
                              FLAG_PARSE_SEMICOLON);
            free(str);
            rcode = last_return_code;
      }
      return rcode;
}

/* built-in 'cd <path>' handler */
static int builtin_cd(struct child_prog *child)
{
      char *newdir;
      if (child->argv[1] == NULL)
            newdir = getenv("HOME");
      else
            newdir = child->argv[1];
      if (chdir(newdir)) {
            printf("cd: %s: %s\n", newdir, strerror(errno));
            return EXIT_FAILURE;
      }
      set_cwd();
      return EXIT_SUCCESS;
}

/* built-in 'env' handler */
static int builtin_env(struct child_prog *dummy)
{
      char **e = environ;
      if (e == NULL) return EXIT_FAILURE;
      for (; *e; e++) {
            puts(*e);
      }
      return EXIT_SUCCESS;
}

/* built-in 'exec' handler */
static int builtin_exec(struct child_prog *child)
{
      if (child->argv[1] == NULL)
            return EXIT_SUCCESS;   /* Really? */
      child->argv++;
      pseudo_exec(child);
      /* never returns */
}

/* built-in 'exit' handler */
static int builtin_exit(struct child_prog *child)
{
      if (child->argv[1] == NULL)
            exit(last_return_code);
      exit (atoi(child->argv[1]));
}

/* built-in 'export VAR=value' handler */
static int builtin_export(struct child_prog *child)
{
      int res = 0;
      char *name = child->argv[1];

      if (name == NULL) {
            return (builtin_env(child));
      }

      name = strdup(name);

      if(name) {
            char *value = strchr(name, '=');

            if (!value) {
                  char *tmp;
                  /* They are exporting something without an =VALUE */

                  value = get_local_var(name);
                  if (value) {
                        size_t ln = strlen(name);

                        tmp = realloc(name, ln+strlen(value)+2);
                        if(tmp==NULL)
                              res = -1;
                        else {
                              sprintf(tmp+ln, "=%s", value);
                              name = tmp;
                        }
                  } else {
                        /* bash does not return an error when trying to export
                         * an undefined variable.  Do likewise. */
                        res = 1;
                  }
            }
      }
      if (res<0)
            perror_msg("export");
      else if(res==0)
            res = set_local_var(name, 1);
      else
            res = 0;
      free(name);
      return res;
}

/* built-in 'fg' and 'bg' handler */
static int builtin_fg_bg(struct child_prog *child)
{
      int i, jobnum;
      struct pipe *pi=NULL;

      if (!interactive)
            return EXIT_FAILURE;
      /* If they gave us no args, assume they want the last backgrounded task */
      if (!child->argv[1]) {
            for (pi = job_list; pi; pi = pi->next) {
                  if (pi->jobid == last_jobid) {
                        break;
                  }
            }
            if (!pi) {
                  error_msg("%s: no current job", child->argv[0]);
                  return EXIT_FAILURE;
            }
      } else {
            if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
                  error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
                  return EXIT_FAILURE;
            }
            for (pi = job_list; pi; pi = pi->next) {
                  if (pi->jobid == jobnum) {
                        break;
                  }
            }
            if (!pi) {
                  error_msg("%s: %d: no such job", child->argv[0], jobnum);
                  return EXIT_FAILURE;
            }
      }

      if (*child->argv[0] == 'f') {
            /* Put the job into the foreground.  */
            tcsetpgrp(shell_terminal, pi->pgrp);
      }

      /* Restart the processes in the job */
      for (i = 0; i < pi->num_progs; i++)
            pi->progs[i].is_stopped = 0;

      if ( (i=kill(- pi->pgrp, SIGCONT)) < 0) {
            if (i == ESRCH) {
                  remove_bg_job(pi);
            } else {
                  perror_msg("kill (SIGCONT)");
            }
      }

      pi->stopped_progs = 0;
      return EXIT_SUCCESS;
}

/* built-in 'help' handler */
static int builtin_help(struct child_prog *dummy)
{
      struct built_in_command *x;

      printf("\nBuilt-in commands:\n");
      printf("-------------------\n");
      for (x = bltins; x->cmd; x++) {
            if (x->descr==NULL)
                  continue;
            printf("%s\t%s\n", x->cmd, x->descr);
      }
      printf("\n\n");
      return EXIT_SUCCESS;
}

/* built-in 'jobs' handler */
static int builtin_jobs(struct child_prog *child)
{
      struct pipe *job;
      char *status_string;

      for (job = job_list; job; job = job->next) {
            if (job->running_progs == job->stopped_progs)
                  status_string = "Stopped";
            else
                  status_string = "Running";

            printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
      }
      return EXIT_SUCCESS;
}


/* built-in 'pwd' handler */
static int builtin_pwd(struct child_prog *dummy)
{
      puts(set_cwd());
      return EXIT_SUCCESS;
}

/* built-in 'read VAR' handler */
static int builtin_read(struct child_prog *child)
{
      int res;

      if (child->argv[1]) {
            char string[BUFSIZ];
            char *var = 0;

            string[0] = 0;  /* In case stdin has only EOF */
            /* read string */
            fgets(string, sizeof(string), stdin);
            chomp(string);
            var = malloc(strlen(child->argv[1])+strlen(string)+2);
            if(var) {
                  sprintf(var, "%s=%s", child->argv[1], string);
                  res = set_local_var(var, 0);
            } else
                  res = -1;
            if (res)
                  fprintf(stderr, "read: %m\n");
            free(var);      /* So not move up to avoid breaking errno */
            return res;
      } else {
            do res=getchar(); while(res!='\n' && res!=EOF);
            return 0;
      }
}

/* built-in 'set VAR=value' handler */
static int builtin_set(struct child_prog *child)
{
      char *temp = child->argv[1];
      struct variables *e;

      if (temp == NULL)
            for(e = top_vars; e; e=e->next)
                  printf("%s=%s\n", e->name, e->value);
      else
            set_local_var(temp, 0);

            return EXIT_SUCCESS;
}


/* Built-in 'shift' handler */
static int builtin_shift(struct child_prog *child)
{
      int n=1;
      if (child->argv[1]) {
            n=atoi(child->argv[1]);
      }
      if (n>=0 && n<global_argc) {
            /* XXX This probably breaks $0 */
            global_argc -= n;
            global_argv += n;
            return EXIT_SUCCESS;
      } else {
            return EXIT_FAILURE;
      }
}

/* Built-in '.' handler (read-in and execute commands from file) */
static int builtin_source(struct child_prog *child)
{
      FILE *input;
      int status;

      if (child->argv[1] == NULL)
            return EXIT_FAILURE;

      /* XXX search through $PATH is missing */
      input = fopen(child->argv[1], "r");
      if (!input) {
            error_msg("Couldn't open file '%s'", child->argv[1]);
            return EXIT_FAILURE;
      }

      /* Now run the file */
      /* XXX argv and argc are broken; need to save old global_argv
       * (pointer only is OK!) on this stack frame,
       * set global_argv=child->argv+1, recurse, and restore. */
      mark_open(fileno(input));
      status = parse_file_outer(input);
      mark_closed(fileno(input));
      fclose(input);
      return (status);
}

static int builtin_umask(struct child_prog *child)
{
      mode_t new_umask;
      const char *arg = child->argv[1];
      char *end;
      if (arg) {
            new_umask=strtoul(arg, &end, 8);
            if (*end!='\0' || end == arg) {
                  return EXIT_FAILURE;
            }
      } else {
            printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
      }
      umask(new_umask);
      return EXIT_SUCCESS;
}

/* built-in 'unset VAR' handler */
static int builtin_unset(struct child_prog *child)
{
      /* bash returned already true */
      unset_local_var(child->argv[1]);
      return EXIT_SUCCESS;
}

static int builtin_not_written(struct child_prog *child)
{
      printf("builtin_%s not written\n",child->argv[0]);
      return EXIT_FAILURE;
}
#endif

static int b_check_space(o_string *o, int len)
{
      /* It would be easy to drop a more restrictive policy
       * in here, such as setting a maximum string length */
      if (o->length + len > o->maxlen) {
            char *old_data = o->data;
            /* assert (data == NULL || o->maxlen != 0); */
            o->maxlen += max(2*len, B_CHUNK);
            o->data = realloc(o->data, 1 + o->maxlen);
            if (o->data == NULL) {
                  free(old_data);
            }
      }
      return o->data == NULL;
}

static int b_addchr(o_string *o, int ch)
{
      debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
      if (b_check_space(o, 1)) return B_NOSPAC;
      o->data[o->length] = ch;
      o->length++;
      o->data[o->length] = '\0';
      return 0;
}

static void b_reset(o_string *o)
{
      o->length = 0;
      o->nonnull = 0;
      if (o->data != NULL) *o->data = '\0';
}

static void b_free(o_string *o)
{
      b_reset(o);
      free(o->data);
      o->data = NULL;
      o->maxlen = 0;
}

/* My analysis of quoting semantics tells me that state information
 * is associated with a destination, not a source.
 */
static int b_addqchr(o_string *o, int ch, int quote)
{
      if (quote && strchr("*?[\\",ch)) {
            int rc;
            rc = b_addchr(o, '\\');
            if (rc) return rc;
      }
      return b_addchr(o, ch);
}

/* belongs in utility.c */
char *simple_itoa(unsigned int i)
{
      /* 21 digits plus null terminator, good for 64-bit or smaller ints */
      static char local[22];
      char *p = &local[21];
      *p-- = '\0';
      do {
            *p-- = '0' + i % 10;
            i /= 10;
      } while (i > 0);
      return p + 1;
}

#ifndef __U_BOOT__
static int b_adduint(o_string *o, unsigned int i)
{
      int r;
      char *p = simple_itoa(i);
      /* no escape checking necessary */
      do r=b_addchr(o, *p++); while (r==0 && *p);
      return r;
}
#endif

static int static_get(struct in_str *i)
{
      int ch = *i->p++;
      if (ch=='\0') return EOF;
      return ch;
}

static int static_peek(struct in_str *i)
{
      return *i->p;
}

#ifndef __U_BOOT__
static inline void cmdedit_set_initial_prompt(void)
{
#ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
      PS1 = NULL;
#else
      PS1 = getenv("PS1");
      if(PS1==0)
            PS1 = "\\w \\$ ";
#endif
}

static inline void setup_prompt_string(int promptmode, char **prompt_str)
{
      debug_printf("setup_prompt_string %d ",promptmode);
#ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
      /* Set up the prompt */
      if (promptmode == 1) {
            free(PS1);
            PS1=xmalloc(strlen(cwd)+4);
            sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
            *prompt_str = PS1;
      } else {
            *prompt_str = PS2;
      }
#else
      *prompt_str = (promptmode==1)? PS1 : PS2;
#endif
      debug_printf("result %s\n",*prompt_str);
}
#endif

static void get_user_input(struct in_str *i)
{
#ifndef __U_BOOT__
      char *prompt_str;
      static char the_command[BUFSIZ];

      setup_prompt_string(i->promptmode, &prompt_str);
#ifdef CONFIG_FEATURE_COMMAND_EDITING
      /*
       ** enable command line editing only while a command line
       ** is actually being read; otherwise, we'll end up bequeathing
       ** atexit() handlers and other unwanted stuff to our
       ** child processes (rob@sysgo.de)
       */
      cmdedit_read_input(prompt_str, the_command);
#else
      fputs(prompt_str, stdout);
      fflush(stdout);
      the_command[0]=fgetc(i->file);
      the_command[1]='\0';
#endif
      fflush(stdout);
      i->p = the_command;
#else
      extern char console_buffer[];
      int n;
      static char the_command[CONFIG_SYS_CBSIZE];

#ifdef CONFIG_BOOT_RETRY_TIME
#  ifdef CONFIG_RESET_TO_RETRY
      extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
#  else
#     error "This currently only works with CONFIG_RESET_TO_RETRY enabled"
#  endif
      reset_cmd_timeout();
#endif
      i->__promptme = 1;
      if (i->promptmode == 1) {
            n = readline(CONFIG_SYS_PROMPT);
      } else {
            n = readline(CONFIG_SYS_PROMPT_HUSH_PS2);
      }
#ifdef CONFIG_BOOT_RETRY_TIME
      if (n == -2) {
        puts("\nTimeout waiting for command\n");
#  ifdef CONFIG_RESET_TO_RETRY
        do_reset(NULL, 0, 0, NULL);
#  else
#     error "This currently only works with CONFIG_RESET_TO_RETRY enabled"
#  endif
      }
#endif
      if (n == -1 ) {
            flag_repeat = 0;
            i->__promptme = 0;
      }
      n = strlen(console_buffer);
      console_buffer[n] = '\n';
      console_buffer[n+1]= '\0';
      if (had_ctrlc()) flag_repeat = 0;
      clear_ctrlc();
      do_repeat = 0;
      if (i->promptmode == 1) {
            if (console_buffer[0] == '\n'&& flag_repeat == 0) {
                  strcpy(the_command,console_buffer);
            }
            else {
                  if (console_buffer[0] != '\n') {
                        strcpy(the_command,console_buffer);
                        flag_repeat = 1;
                  }
                  else {
                        do_repeat = 1;
                  }
            }
            i->p = the_command;
      }
      else {
            if (console_buffer[0] != '\n') {
                  if (strlen(the_command) + strlen(console_buffer)
                      < CONFIG_SYS_CBSIZE) {
                        n = strlen(the_command);
                        the_command[n-1] = ' ';
                        strcpy(&the_command[n],console_buffer);
                  }
                  else {
                        the_command[0] = '\n';
                        the_command[1] = '\0';
                        flag_repeat = 0;
                  }
            }
            if (i->__promptme == 0) {
                  the_command[0] = '\n';
                  the_command[1] = '\0';
            }
            i->p = console_buffer;
      }
#endif
}

/* This is the magic location that prints prompts
 * and gets data back from the user */
static int file_get(struct in_str *i)
{
      int ch;

      ch = 0;
      /* If there is data waiting, eat it up */
      if (i->p && *i->p) {
            ch = *i->p++;
      } else {
            /* need to double check i->file because we might be doing something
             * more complicated by now, like sourcing or substituting. */
#ifndef __U_BOOT__
            if (i->__promptme && interactive && i->file == stdin) {
                  while(! i->p || (interactive && strlen(i->p)==0) ) {
#else
                  while(! i->p  || strlen(i->p)==0 ) {
#endif
                        get_user_input(i);
                  }
                  i->promptmode=2;
#ifndef __U_BOOT__
                  i->__promptme = 0;
#endif
                  if (i->p && *i->p) {
                        ch = *i->p++;
                  }
#ifndef __U_BOOT__
            } else {
                  ch = fgetc(i->file);
            }

#endif
            debug_printf("b_getch: got a %d\n", ch);
      }
#ifndef __U_BOOT__
      if (ch == '\n') i->__promptme=1;
#endif
      return ch;
}

/* All the callers guarantee this routine will never be
 * used right after a newline, so prompting is not needed.
 */
static int file_peek(struct in_str *i)
{
#ifndef __U_BOOT__
      if (i->p && *i->p) {
#endif
            return *i->p;
#ifndef __U_BOOT__
      } else {
            i->peek_buf[0] = fgetc(i->file);
            i->peek_buf[1] = '\0';
            i->p = i->peek_buf;
            debug_printf("b_peek: got a %d\n", *i->p);
            return *i->p;
      }
#endif
}

#ifndef __U_BOOT__
static void setup_file_in_str(struct in_str *i, FILE *f)
#else
static void setup_file_in_str(struct in_str *i)
#endif
{
      i->peek = file_peek;
      i->get = file_get;
      i->__promptme=1;
      i->promptmode=1;
#ifndef __U_BOOT__
      i->file = f;
#endif
      i->p = NULL;
}

static void setup_string_in_str(struct in_str *i, const char *s)
{
      i->peek = static_peek;
      i->get = static_get;
      i->__promptme=1;
      i->promptmode=1;
      i->p = s;
}

#ifndef __U_BOOT__
static void mark_open(int fd)
{
      struct close_me *new = xmalloc(sizeof(struct close_me));
      new->fd = fd;
      new->next = close_me_head;
      close_me_head = new;
}

static void mark_closed(int fd)
{
      struct close_me *tmp;
      if (close_me_head == NULL || close_me_head->fd != fd)
            error_msg_and_die("corrupt close_me");
      tmp = close_me_head;
      close_me_head = close_me_head->next;
      free(tmp);
}

static void close_all(void)
{
      struct close_me *c;
      for (c=close_me_head; c; c=c->next) {
            close(c->fd);
      }
      close_me_head = NULL;
}

/* squirrel != NULL means we squirrel away copies of stdin, stdout,
 * and stderr if they are redirected. */
static int setup_redirects(struct child_prog *prog, int squirrel[])
{
      int openfd, mode;
      struct redir_struct *redir;

      for (redir=prog->redirects; redir; redir=redir->next) {
            if (redir->dup == -1 && redir->word.gl_pathv == NULL) {
                  /* something went wrong in the parse.  Pretend it didn't happen */
                  continue;
            }
            if (redir->dup == -1) {
                  mode=redir_table[redir->type].mode;
                  openfd = open(redir->word.gl_pathv[0], mode, 0666);
                  if (openfd < 0) {
                  /* this could get lost if stderr has been redirected, but
                     bash and ash both lose it as well (though zsh doesn't!) */
                        perror_msg("error opening %s", redir->word.gl_pathv[0]);
                        return 1;
                  }
            } else {
                  openfd = redir->dup;
            }

            if (openfd != redir->fd) {
                  if (squirrel && redir->fd < 3) {
                        squirrel[redir->fd] = dup(redir->fd);
                  }
                  if (openfd == -3) {
                        close(openfd);
                  } else {
                        dup2(openfd, redir->fd);
                        if (redir->dup == -1)
                              close (openfd);
                  }
            }
      }
      return 0;
}

static void restore_redirects(int squirrel[])
{
      int i, fd;
      for (i=0; i<3; i++) {
            fd = squirrel[i];
            if (fd != -1) {
                  /* No error checking.  I sure wouldn't know what
                   * to do with an error if I found one! */
                  dup2(fd, i);
                  close(fd);
            }
      }
}

/* never returns */
/* XXX no exit() here.  If you don't exec, use _exit instead.
 * The at_exit handlers apparently confuse the calling process,
 * in particular stdin handling.  Not sure why? */
static void pseudo_exec(struct child_prog *child)
{
      int i, rcode;
      char *p;
      struct built_in_command *x;
      if (child->argv) {
            for (i=0; is_assignment(child->argv[i]); i++) {
                  debug_printf("pid %d environment modification: %s\n",getpid(),child->argv[i]);
                  p = insert_var_value(child->argv[i]);
                  putenv(strdup(p));
                  if (p != child->argv[i]) free(p);
            }
            child->argv+=i;  /* XXX this hack isn't so horrible, since we are about
                              to exit, and therefore don't need to keep data
                              structures consistent for free() use. */
            /* If a variable is assigned in a forest, and nobody listens,
             * was it ever really set?
             */
            if (child->argv[0] == NULL) {
                  _exit(EXIT_SUCCESS);
            }

            /*
             * Check if the command matches any of the builtins.
             * Depending on context, this might be redundant.  But it's
             * easier to waste a few CPU cycles than it is to figure out
             * if this is one of those cases.
             */
            for (x = bltins; x->cmd; x++) {
                  if (strcmp(child->argv[0], x->cmd) == 0 ) {
                        debug_printf("builtin exec %s\n", child->argv[0]);
                        rcode = x->function(child);
                        fflush(stdout);
                        _exit(rcode);
                  }
            }

            /* Check if the command matches any busybox internal commands
             * ("applets") here.
             * FIXME: This feature is not 100% safe, since
             * BusyBox is not fully reentrant, so we have no guarantee the things
             * from the .bss are still zeroed, or that things from .data are still
             * at their defaults.  We could exec ourself from /proc/self/exe, but I
             * really dislike relying on /proc for things.  We could exec ourself
             * from global_argv[0], but if we are in a chroot, we may not be able
             * to find ourself... */
#ifdef CONFIG_FEATURE_SH_STANDALONE_SHELL
            {
                  int argc_l;
                  char** argv_l=child->argv;
                  char *name = child->argv[0];

#ifdef CONFIG_FEATURE_SH_APPLETS_ALWAYS_WIN
                  /* Following discussions from November 2000 on the busybox mailing
                   * list, the default configuration, (without
                   * get_last_path_component()) lets the user force use of an
                   * external command by specifying the full (with slashes) filename.
                   * If you enable CONFIG_FEATURE_SH_APPLETS_ALWAYS_WIN then applets
                   * _aways_ override external commands, so if you want to run
                   * /bin/cat, it will use BusyBox cat even if /bin/cat exists on the
                   * filesystem and is _not_ busybox.  Some systems may want this,
                   * most do not.  */
                  name = get_last_path_component(name);
#endif
                  /* Count argc for use in a second... */
                  for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
                  optind = 1;
                  debug_printf("running applet %s\n", name);
                  run_applet_by_name(name, argc_l, child->argv);
            }
#endif
            debug_printf("exec of %s\n",child->argv[0]);
            execvp(child->argv[0],child->argv);
            perror_msg("couldn't exec: %s",child->argv[0]);
            _exit(1);
      } else if (child->group) {
            debug_printf("runtime nesting to group\n");
            interactive=0;    /* crucial!!!! */
            rcode = run_list_real(child->group);
            /* OK to leak memory by not calling free_pipe_list,
             * since this process is about to exit */
            _exit(rcode);
      } else {
            /* Can happen.  See what bash does with ">foo" by itself. */
            debug_printf("trying to pseudo_exec null command\n");
            _exit(EXIT_SUCCESS);
      }
}

static void insert_bg_job(struct pipe *pi)
{
      struct pipe *thejob;

      /* Linear search for the ID of the job to use */
      pi->jobid = 1;
      for (thejob = job_list; thejob; thejob = thejob->next)
            if (thejob->jobid >= pi->jobid)
                  pi->jobid = thejob->jobid + 1;

      /* add thejob to the list of running jobs */
      if (!job_list) {
            thejob = job_list = xmalloc(sizeof(*thejob));
      } else {
            for (thejob = job_list; thejob->next; thejob = thejob->next) /* nothing */;
            thejob->next = xmalloc(sizeof(*thejob));
            thejob = thejob->next;
      }

      /* physically copy the struct job */
      memcpy(thejob, pi, sizeof(struct pipe));
      thejob->next = NULL;
      thejob->running_progs = thejob->num_progs;
      thejob->stopped_progs = 0;
      thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */

      /*if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0]) */
      {
            char *bar=thejob->text;
            char **foo=pi->progs[0].argv;
            while(foo && *foo) {
                  bar += sprintf(bar, "%s ", *foo++);
            }
      }

      /* we don't wait for background thejobs to return -- append it
         to the list of backgrounded thejobs and leave it alone */
      printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
      last_bg_pid = thejob->progs[0].pid;
      last_jobid = thejob->jobid;
}

/* remove a backgrounded job */
static void remove_bg_job(struct pipe *pi)
{
      struct pipe *prev_pipe;

      if (pi == job_list) {
            job_list = pi->next;
      } else {
            prev_pipe = job_list;
            while (prev_pipe->next != pi)
                  prev_pipe = prev_pipe->next;
            prev_pipe->next = pi->next;
      }
      if (job_list)
            last_jobid = job_list->jobid;
      else
            last_jobid = 0;

      pi->stopped_progs = 0;
      free_pipe(pi, 0);
      free(pi);
}

/* Checks to see if any processes have exited -- if they
   have, figure out why and see if a job has completed */
static int checkjobs(struct pipe* fg_pipe)
{
      int attributes;
      int status;
      int prognum = 0;
      struct pipe *pi;
      pid_t childpid;

      attributes = WUNTRACED;
      if (fg_pipe==NULL) {
            attributes |= WNOHANG;
      }

      while ((childpid = waitpid(-1, &status, attributes)) > 0) {
            if (fg_pipe) {
                  int i, rcode = 0;
                  for (i=0; i < fg_pipe->num_progs; i++) {
                        if (fg_pipe->progs[i].pid == childpid) {
                              if (i==fg_pipe->num_progs-1)
                                    rcode=WEXITSTATUS(status);
                              (fg_pipe->num_progs)--;
                              return(rcode);
                        }
                  }
            }

            for (pi = job_list; pi; pi = pi->next) {
                  prognum = 0;
                  while (prognum < pi->num_progs && pi->progs[prognum].pid != childpid) {
                        prognum++;
                  }
                  if (prognum < pi->num_progs)
                        break;
            }

            if(pi==NULL) {
                  debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
                  continue;
            }

            if (WIFEXITED(status) || WIFSIGNALED(status)) {
                  /* child exited */
                  pi->running_progs--;
                  pi->progs[prognum].pid = 0;

                  if (!pi->running_progs) {
                        printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
                        remove_bg_job(pi);
                  }
            } else {
                  /* child stopped */
                  pi->stopped_progs++;
                  pi->progs[prognum].is_stopped = 1;

#if 0
                  /* Printing this stuff is a pain, since it tends to
                   * overwrite the prompt an inconveinient moments.  So
                   * don't do that.  */
                  if (pi->stopped_progs == pi->num_progs) {
                        printf("\n"JOB_STATUS_FORMAT, pi->jobid, "Stopped", pi->text);
                  }
#endif
            }
      }

      if (childpid == -1 && errno != ECHILD)
            perror_msg("waitpid");

      /* move the shell to the foreground */
      /*if (interactive && tcsetpgrp(shell_terminal, getpgid(0))) */
      /*    perror_msg("tcsetpgrp-2"); */
      return -1;
}

/* Figure out our controlling tty, checking in order stderr,
 * stdin, and stdout.  If check_pgrp is set, also check that
 * we belong to the foreground process group associated with
 * that tty.  The value of shell_terminal is needed in order to call
 * tcsetpgrp(shell_terminal, ...); */
void controlling_tty(int check_pgrp)
{
      pid_t curpgrp;

      if ((curpgrp = tcgetpgrp(shell_terminal = 2)) < 0
                  && (curpgrp = tcgetpgrp(shell_terminal = 0)) < 0
                  && (curpgrp = tcgetpgrp(shell_terminal = 1)) < 0)
            goto shell_terminal_error;

      if (check_pgrp && curpgrp != getpgid(0))
            goto shell_terminal_error;

      return;

shell_terminal_error:
            shell_terminal = -1;
            return;
}
#endif

/* run_pipe_real() starts all the jobs, but doesn't wait for anything
 * to finish.  See checkjobs().
 *
 * return code is normally -1, when the caller has to wait for children
 * to finish to determine the exit status of the pipe.  If the pipe
 * is a simple builtin command, however, the action is done by the
 * time run_pipe_real returns, and the exit code is provided as the
 * return value.
 *
 * The input of the pipe is always stdin, the output is always
 * stdout.  The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
 * because it tries to avoid running the command substitution in
 * subshell, when that is in fact necessary.  The subshell process
 * now has its stdout directed to the input of the appropriate pipe,
 * so this routine is noticeably simpler.
 */
static int run_pipe_real(struct pipe *pi)
{
      int i;
#ifndef __U_BOOT__
      int nextin, nextout;
      int pipefds[2];                     /* pipefds[0] is for reading */
      struct child_prog *child;
      struct built_in_command *x;
      char *p;
# if __GNUC__
      /* Avoid longjmp clobbering */
      (void) &i;
      (void) &nextin;
      (void) &nextout;
      (void) &child;
# endif
#else
      int nextin;
      int flag = do_repeat ? CMD_FLAG_REPEAT : 0;
      struct child_prog *child;
      cmd_tbl_t *cmdtp;
      char *p;
# if __GNUC__
      /* Avoid longjmp clobbering */
      (void) &i;
      (void) &nextin;
      (void) &child;
# endif
#endif      /* __U_BOOT__ */

      nextin = 0;
#ifndef __U_BOOT__
      pi->pgrp = -1;
#endif

      /* Check if this is a simple builtin (not part of a pipe).
       * Builtins within pipes have to fork anyway, and are handled in
       * pseudo_exec.  "echo foo | read bar" doesn't work on bash, either.
       */
      if (pi->num_progs == 1) child = & (pi->progs[0]);
#ifndef __U_BOOT__
      if (pi->num_progs == 1 && child->group && child->subshell == 0) {
            int squirrel[] = {-1, -1, -1};
            int rcode;
            debug_printf("non-subshell grouping\n");
            setup_redirects(child, squirrel);
            /* XXX could we merge code with following builtin case,
             * by creating a pseudo builtin that calls run_list_real? */
            rcode = run_list_real(child->group);
            restore_redirects(squirrel);
#else
            if (pi->num_progs == 1 && child->group) {
            int rcode;
            debug_printf("non-subshell grouping\n");
            rcode = run_list_real(child->group);
#endif
            return rcode;
      } else if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
            for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
            if (i!=0 && child->argv[i]==NULL) {
                  /* assignments, but no command: set the local environment */
                  for (i=0; child->argv[i]!=NULL; i++) {

                        /* Ok, this case is tricky.  We have to decide if this is a
                         * local variable, or an already exported variable.  If it is
                         * already exported, we have to export the new value.  If it is
                         * not exported, we need only set this as a local variable.
                         * This junk is all to decide whether or not to export this
                         * variable. */
                        int export_me=0;
                        char *name, *value;
                        name = xstrdup(child->argv[i]);
                        debug_printf("Local environment set: %s\n", name);
                        value = strchr(name, '=');
                        if (value)
                              *value=0;
#ifndef __U_BOOT__
                        if ( get_local_var(name)) {
                              export_me=1;
                        }
#endif
                        free(name);
                        p = insert_var_value(child->argv[i]);
                        set_local_var(p, export_me);
                        if (p != child->argv[i]) free(p);
                  }
                  return EXIT_SUCCESS;   /* don't worry about errors in set_local_var() yet */
            }
            for (i = 0; is_assignment(child->argv[i]); i++) {
                  p = insert_var_value(child->argv[i]);
#ifndef __U_BOOT__
                  putenv(strdup(p));
#else
                  set_local_var(p, 0);
#endif
                  if (p != child->argv[i]) {
                        child->sp--;
                        free(p);
                  }
            }
            if (child->sp) {
                  char * str = NULL;

                  str = make_string((child->argv + i));
                  parse_string_outer(str, FLAG_EXIT_FROM_LOOP | FLAG_REPARSING);
                  free(str);
                  return last_return_code;
            }
#ifndef __U_BOOT__
            for (x = bltins; x->cmd; x++) {
                  if (strcmp(child->argv[i], x->cmd) == 0 ) {
                        int squirrel[] = {-1, -1, -1};
                        int rcode;
                        if (x->function == builtin_exec && child->argv[i+1]==NULL) {
                              debug_printf("magic exec\n");
                              setup_redirects(child,NULL);
                              return EXIT_SUCCESS;
                        }
                        debug_printf("builtin inline %s\n", child->argv[0]);
                        /* XXX setup_redirects acts on file descriptors, not FILEs.
                         * This is perfect for work that comes after exec().
                         * Is it really safe for inline use?  Experimentally,
                         * things seem to work with glibc. */
                        setup_redirects(child, squirrel);
#else
                  /* check ";", because ,example , argv consist from
                   * "help;flinfo" must not execute
                   */
                  if (strchr(child->argv[i], ';')) {
                        printf ("Unknown command '%s' - try 'help' or use 'run' command\n",
                              child->argv[i]);
                        return -1;
                  }
                  /* Look up command in command table */


                  if ((cmdtp = find_cmd(child->argv[i])) == NULL) {
                        printf ("Unknown command '%s' - try 'help'\n", child->argv[i]);
                        return -1;  /* give up after bad command */
                  } else {
                        int rcode;
#if defined(CONFIG_CMD_BOOTD)
          extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);

                        /* avoid "bootd" recursion */
                        if (cmdtp->cmd == do_bootd) {
                              if (flag & CMD_FLAG_BOOTD) {
                                    printf ("'bootd' recursion detected\n");
                                    return -1;
                              }
                        else
                              flag |= CMD_FLAG_BOOTD;
                        }
#endif
                        /* found - check max args */
                        if ((child->argc - i) > cmdtp->maxargs)
                              return cmd_usage(cmdtp);
#endif
                        child->argv+=i;  /* XXX horrible hack */
#ifndef __U_BOOT__
                        rcode = x->function(child);
#else
                        /* OK - call function to do the command */

                        rcode = (cmdtp->cmd)
(cmdtp, flag,child->argc-i,&child->argv[i]);
                        if ( !cmdtp->repeatable )
                              flag_repeat = 0;


#endif
                        child->argv-=i;  /* XXX restore hack so free() can work right */
#ifndef __U_BOOT__

                        restore_redirects(squirrel);
#endif

                        return rcode;
                  }
            }
#ifndef __U_BOOT__
      }

      for (i = 0; i < pi->num_progs; i++) {
            child = & (pi->progs[i]);

            /* pipes are inserted between pairs of commands */
            if ((i + 1) < pi->num_progs) {
                  if (pipe(pipefds)<0) perror_msg_and_die("pipe");
                  nextout = pipefds[1];
            } else {
                  nextout=1;
                  pipefds[0] = -1;
            }

            /* XXX test for failed fork()? */
            if (!(child->pid = fork())) {
                  /* Set the handling for job control signals back to the default.  */
                  signal(SIGINT, SIG_DFL);
                  signal(SIGQUIT, SIG_DFL);
                  signal(SIGTERM, SIG_DFL);
                  signal(SIGTSTP, SIG_DFL);
                  signal(SIGTTIN, SIG_DFL);
                  signal(SIGTTOU, SIG_DFL);
                  signal(SIGCHLD, SIG_DFL);

                  close_all();

                  if (nextin != 0) {
                        dup2(nextin, 0);
                        close(nextin);
                  }
                  if (nextout != 1) {
                        dup2(nextout, 1);
                        close(nextout);
                  }
                  if (pipefds[0]!=-1) {
                        close(pipefds[0]);  /* opposite end of our output pipe */
                  }

                  /* Like bash, explicit redirects override pipes,
                   * and the pipe fd is available for dup'ing. */
                  setup_redirects(child,NULL);

                  if (interactive && pi->followup!=PIPE_BG) {
                        /* If we (the child) win the race, put ourselves in the process
                         * group whose leader is the first process in this pipe. */
                        if (pi->pgrp < 0) {
                              pi->pgrp = getpid();
                        }
                        if (setpgid(0, pi->pgrp) == 0) {
                              tcsetpgrp(2, pi->pgrp);
                        }
                  }

                  pseudo_exec(child);
            }


            /* put our child in the process group whose leader is the
               first process in this pipe */
            if (pi->pgrp < 0) {
                  pi->pgrp = child->pid;
            }
            /* Don't check for errors.  The child may be dead already,
             * in which case setpgid returns error code EACCES. */
            setpgid(child->pid, pi->pgrp);

            if (nextin != 0)
                  close(nextin);
            if (nextout != 1)
                  close(nextout);

            /* If there isn't another process, nextin is garbage
               but it doesn't matter */
            nextin = pipefds[0];
      }
#endif
      return -1;
}

static int run_list_real(struct pipe *pi)
{
      char *save_name = NULL;
      char **list = NULL;
      char **save_list = NULL;
      struct pipe *rpipe;
      int flag_rep = 0;
#ifndef __U_BOOT__
      int save_num_progs;
#endif
      int rcode=0, flag_skip=1;
      int flag_restore = 0;
      int if_code=0, next_if_code=0;  /* need double-buffer to handle elif */
      reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
      /* check syntax for "for" */
      for (rpipe = pi; rpipe; rpipe = rpipe->next) {
            if ((rpipe->r_mode == RES_IN ||
                rpipe->r_mode == RES_FOR) &&
                (rpipe->next == NULL)) {
                        syntax();
#ifdef __U_BOOT__
                        flag_repeat = 0;
#endif
                        return 1;
            }
            if ((rpipe->r_mode == RES_IN &&
                  (rpipe->next->r_mode == RES_IN &&
                  rpipe->next->progs->argv != NULL))||
                  (rpipe->r_mode == RES_FOR &&
                  rpipe->next->r_mode != RES_IN)) {
                        syntax();
#ifdef __U_BOOT__
                        flag_repeat = 0;
#endif
                        return 1;
            }
      }
      for (; pi; pi = (flag_restore != 0) ? rpipe : pi->next) {
            if (pi->r_mode == RES_WHILE || pi->r_mode == RES_UNTIL ||
                  pi->r_mode == RES_FOR) {
#ifdef __U_BOOT__
                        /* check Ctrl-C */
                        ctrlc();
                        if ((had_ctrlc())) {
                              return 1;
                        }
#endif
                        flag_restore = 0;
                        if (!rpipe) {
                              flag_rep = 0;
                              rpipe = pi;
                        }
            }
            rmode = pi->r_mode;
            debug_printf("rmode=%d  if_code=%d  next_if_code=%d skip_more=%d\n", rmode, if_code, next_if_code, skip_more_in_this_rmode);
            if (rmode == skip_more_in_this_rmode && flag_skip) {
                  if (pi->followup == PIPE_SEQ) flag_skip=0;
                  continue;
            }
            flag_skip = 1;
            skip_more_in_this_rmode = RES_XXXX;
            if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
            if (rmode == RES_THEN &&  if_code) continue;
            if (rmode == RES_ELSE && !if_code) continue;
            if (rmode == RES_ELIF && !if_code) break;
            if (rmode == RES_FOR && pi->num_progs) {
                  if (!list) {
                        /* if no variable values after "in" we skip "for" */
                        if (!pi->next->progs->argv) continue;
                        /* create list of variable values */
                        list = make_list_in(pi->next->progs->argv,
                              pi->progs->argv[0]);
                        save_list = list;
                        save_name = pi->progs->argv[0];
                        pi->progs->argv[0] = NULL;
                        flag_rep = 1;
                  }
                  if (!(*list)) {
                        free(pi->progs->argv[0]);
                        free(save_list);
                        list = NULL;
                        flag_rep = 0;
                        pi->progs->argv[0] = save_name;
#ifndef __U_BOOT__
                        pi->progs->glob_result.gl_pathv[0] =
                              pi->progs->argv[0];
#endif
                        continue;
                  } else {
                        /* insert new value from list for variable */
                        if (pi->progs->argv[0])
                              free(pi->progs->argv[0]);
                        pi->progs->argv[0] = *list++;
#ifndef __U_BOOT__
                        pi->progs->glob_result.gl_pathv[0] =
                              pi->progs->argv[0];
#endif
                  }
            }
            if (rmode == RES_IN) continue;
            if (rmode == RES_DO) {
                  if (!flag_rep) continue;
            }
            if ((rmode == RES_DONE)) {
                  if (flag_rep) {
                        flag_restore = 1;
                  } else {
                        rpipe = NULL;
                  }
            }
            if (pi->num_progs == 0) continue;
#ifndef __U_BOOT__
            save_num_progs = pi->num_progs; /* save number of programs */
#endif
            rcode = run_pipe_real(pi);
            debug_printf("run_pipe_real returned %d\n",rcode);
#ifndef __U_BOOT__
            if (rcode!=-1) {
                  /* We only ran a builtin: rcode was set by the return value
                   * of run_pipe_real(), and we don't need to wait for anything. */
            } else if (pi->followup==PIPE_BG) {
                  /* XXX check bash's behavior with nontrivial pipes */
                  /* XXX compute jobid */
                  /* XXX what does bash do with attempts to background builtins? */
                  insert_bg_job(pi);
                  rcode = EXIT_SUCCESS;
            } else {
                  if (interactive) {
                        /* move the new process group into the foreground */
                        if (tcsetpgrp(shell_terminal, pi->pgrp) && errno != ENOTTY)
                              perror_msg("tcsetpgrp-3");
                        rcode = checkjobs(pi);
                        /* move the shell to the foreground */
                        if (tcsetpgrp(shell_terminal, getpgid(0)) && errno != ENOTTY)
                              perror_msg("tcsetpgrp-4");
                  } else {
                        rcode = checkjobs(pi);
                  }
                  debug_printf("checkjobs returned %d\n",rcode);
            }
            last_return_code=rcode;
#else
            if (rcode < -1) {
                  last_return_code = -rcode - 2;
                  return -2;  /* exit */
            }
            last_return_code=(rcode == 0) ? 0 : 1;
#endif
#ifndef __U_BOOT__
            pi->num_progs = save_num_progs; /* restore number of programs */
#endif
            if ( rmode == RES_IF || rmode == RES_ELIF )
                  next_if_code=rcode;  /* can be overwritten a number of times */
            if (rmode == RES_WHILE)
                  flag_rep = !last_return_code;
            if (rmode == RES_UNTIL)
                  flag_rep = last_return_code;
            if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
                 (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
                  skip_more_in_this_rmode=rmode;
#ifndef __U_BOOT__
            checkjobs(NULL);
#endif
      }
      return rcode;
}

/* broken, of course, but OK for testing */
static char *indenter(int i)
{
      static char blanks[]="                                    ";
      return &blanks[sizeof(blanks)-i-1];
}

/* return code is the exit status of the pipe */
static int free_pipe(struct pipe *pi, int indent)
{
      char **p;
      struct child_prog *child;
#ifndef __U_BOOT__
      struct redir_struct *r, *rnext;
#endif
      int a, i, ret_code=0;
      char *ind = indenter(indent);

#ifndef __U_BOOT__
      if (pi->stopped_progs > 0)
            return ret_code;
      final_printf("%s run pipe: (pid %d)\n",ind,getpid());
#endif
      for (i=0; i<pi->num_progs; i++) {
            child = &pi->progs[i];
            final_printf("%s  command %d:\n",ind,i);
            if (child->argv) {
                  for (a=0,p=child->argv; *p; a++,p++) {
                        final_printf("%s   argv[%d] = %s\n",ind,a,*p);
                  }
#ifndef __U_BOOT__
                  globfree(&child->glob_result);
#else
                  for (a = 0; a < child->argc; a++) {
                        free(child->argv[a]);
                  }
                              free(child->argv);
                  child->argc = 0;
#endif
                  child->argv=NULL;
            } else if (child->group) {
#ifndef __U_BOOT__
                  final_printf("%s   begin group (subshell:%d)\n",ind, child->subshell);
#endif
                  ret_code = free_pipe_list(child->group,indent+3);
                  final_printf("%s   end group\n",ind);
            } else {
                  final_printf("%s   (nil)\n",ind);
            }
#ifndef __U_BOOT__
            for (r=child->redirects; r; r=rnext) {
                  final_printf("%s   redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
                  if (r->dup == -1) {
                        /* guard against the case >$FOO, where foo is unset or blank */
                        if (r->word.gl_pathv) {
                              final_printf(" %s\n", *r->word.gl_pathv);
                              globfree(&r->word);
                        }
                  } else {
                        final_printf("&%d\n", r->dup);
                  }
                  rnext=r->next;
                  free(r);
            }
            child->redirects=NULL;
#endif
      }
      free(pi->progs);   /* children are an array, they get freed all at once */
      pi->progs=NULL;
      return ret_code;
}

static int free_pipe_list(struct pipe *head, int indent)
{
      int rcode=0;   /* if list has no members */
      struct pipe *pi, *next;
      char *ind = indenter(indent);
      for (pi=head; pi; pi=next) {
            final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
            rcode = free_pipe(pi, indent);
            final_printf("%s pipe followup code %d\n", ind, pi->followup);
            next=pi->next;
            pi->next=NULL;
            free(pi);
      }
      return rcode;
}

/* Select which version we will use */
static int run_list(struct pipe *pi)
{
      int rcode=0;
#ifndef __U_BOOT__
      if (fake_mode==0) {
#endif
            rcode = run_list_real(pi);
#ifndef __U_BOOT__
      }
#endif
      /* free_pipe_list has the side effect of clearing memory
       * In the long run that function can be merged with run_list_real,
       * but doing that now would hobble the debugging effort. */
      free_pipe_list(pi,0);
      return rcode;
}

/* The API for glob is arguably broken.  This routine pushes a non-matching
 * string into the output structure, removing non-backslashed backslashes.
 * If someone can prove me wrong, by performing this function within the
 * original glob(3) api, feel free to rewrite this routine into oblivion.
 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
 * XXX broken if the last character is '\\', check that before calling.
 */
#ifndef __U_BOOT__
static int globhack(const char *src, int flags, glob_t *pglob)
{
      int cnt=0, pathc;
      const char *s;
      char *dest;
      for (cnt=1, s=src; s && *s; s++) {
            if (*s == '\\') s++;
            cnt++;
      }
      dest = malloc(cnt);
      if (!dest) return GLOB_NOSPACE;
      if (!(flags & GLOB_APPEND)) {
            pglob->gl_pathv=NULL;
            pglob->gl_pathc=0;
            pglob->gl_offs=0;
            pglob->gl_offs=0;
      }
      pathc = ++pglob->gl_pathc;
      pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
      if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
      pglob->gl_pathv[pathc-1]=dest;
      pglob->gl_pathv[pathc]=NULL;
      for (s=src; s && *s; s++, dest++) {
            if (*s == '\\') s++;
            *dest = *s;
      }
      *dest='\0';
      return 0;
}

/* XXX broken if the last character is '\\', check that before calling */
static int glob_needed(const char *s)
{
      for (; *s; s++) {
            if (*s == '\\') s++;
            if (strchr("*[?",*s)) return 1;
      }
      return 0;
}

#if 0
static void globprint(glob_t *pglob)
{
      int i;
      debug_printf("glob_t at %p:\n", pglob);
      debug_printf("  gl_pathc=%d  gl_pathv=%p  gl_offs=%d  gl_flags=%d\n",
            pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
      for (i=0; i<pglob->gl_pathc; i++)
            debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
                  pglob->gl_pathv[i], pglob->gl_pathv[i]);
}
#endif

static int xglob(o_string *dest, int flags, glob_t *pglob)
{
      int gr;

      /* short-circuit for null word */
      /* we can code this better when the debug_printf's are gone */
      if (dest->length == 0) {
            if (dest->nonnull) {
                  /* bash man page calls this an "explicit" null */
                  gr = globhack(dest->data, flags, pglob);
                  debug_printf("globhack returned %d\n",gr);
            } else {
                  return 0;
            }
      } else if (glob_needed(dest->data)) {
            gr = glob(dest->data, flags, NULL, pglob);
            debug_printf("glob returned %d\n",gr);
            if (gr == GLOB_NOMATCH) {
                  /* quote removal, or more accurately, backslash removal */
                  gr = globhack(dest->data, flags, pglob);
                  debug_printf("globhack returned %d\n",gr);
            }
      } else {
            gr = globhack(dest->data, flags, pglob);
            debug_printf("globhack returned %d\n",gr);
      }
      if (gr == GLOB_NOSPACE)
            error_msg_and_die("out of memory during glob");
      if (gr != 0) { /* GLOB_ABORTED ? */
            error_msg("glob(3) error %d",gr);
      }
      /* globprint(glob_target); */
      return gr;
}
#endif

#ifdef __U_BOOT__
static char *get_dollar_var(char ch);
#endif

/* This is used to get/check local shell variables */
static char *get_local_var(const char *s)
{
      struct variables *cur;

      if (!s)
            return NULL;

#ifdef __U_BOOT__
      if (*s == '$')
            return get_dollar_var(s[1]);
#endif

      for (cur = top_vars; cur; cur=cur->next)
            if(strcmp(cur->name, s)==0)
                  return cur->value;
      return NULL;
}

/* This is used to set local shell variables
   flg_export==0 if only local (not exporting) variable
   flg_export==1 if "new" exporting environ
   flg_export>1  if current startup environ (not call putenv()) */
int set_local_var(const char *s, int flg_export)
{
      char *name, *value;
      int result=0;
      struct variables *cur;

#ifdef __U_BOOT__
      /* might be possible! */
      if (!isalpha(*s))
            return -1;
#endif

      name=strdup(s);

#ifdef __U_BOOT__
      if (getenv(name) != NULL) {
            printf ("ERROR: "
                        "There is a global environment variable with the same name.\n");
            free(name);
            return -1;
      }
#endif
      /* Assume when we enter this function that we are already in
       * NAME=VALUE format.  So the first order of business is to
       * split 's' on the '=' into 'name' and 'value' */
      value = strchr(name, '=');
      if (value==0 && ++value==0) {
            free(name);
            return -1;
      }
      *value++ = 0;

      for(cur = top_vars; cur; cur = cur->next) {
            if(strcmp(cur->name, name)==0)
                  break;
      }

      if(cur) {
            if(strcmp(cur->value, value)==0) {
                  if(flg_export>0 && cur->flg_export==0)
                        cur->flg_export=flg_export;
                  else
                        result++;
            } else {
                  if(cur->flg_read_only) {
                        error_msg("%s: readonly variable", name);
                        result = -1;
                  } else {
                        if(flg_export>0 || cur->flg_export>1)
                              cur->flg_export=1;
                        free(cur->value);

                        cur->value = strdup(value);
                  }
            }
      } else {
            cur = malloc(sizeof(struct variables));
            if(!cur) {
                  result = -1;
            } else {
                  cur->name = strdup(name);
                  if(cur->name == 0) {
                        free(cur);
                        result = -1;
                  } else {
                        struct variables *bottom = top_vars;
                        cur->value = strdup(value);
                        cur->next = 0;
                        cur->flg_export = flg_export;
                        cur->flg_read_only = 0;
                        while(bottom->next) bottom=bottom->next;
                        bottom->next = cur;
                  }
            }
      }

#ifndef __U_BOOT__
      if(result==0 && cur->flg_export==1) {
            *(value-1) = '=';
            result = putenv(name);
      } else {
#endif
            free(name);
#ifndef __U_BOOT__
            if(result>0)            /* equivalent to previous set */
                  result = 0;
      }
#endif
      return result;
}

void unset_local_var(const char *name)
{
      struct variables *cur;

      if (name) {
            for (cur = top_vars; cur; cur=cur->next) {
                  if(strcmp(cur->name, name)==0)
                        break;
            }
            if(cur!=0) {
                  struct variables *next = top_vars;
                  if(cur->flg_read_only) {
                        error_msg("%s: readonly variable", name);
                        return;
                  } else {
#ifndef __U_BOOT__
                        if(cur->flg_export)
                              unsetenv(cur->name);
#endif
                        free(cur->name);
                        free(cur->value);
                        while (next->next != cur)
                              next = next->next;
                        next->next = cur->next;
                  }
                  free(cur);
            }
      }
}

static int is_assignment(const char *s)
{
      if (s == NULL)
            return 0;

      if (!isalpha(*s)) return 0;
      ++s;
      while(isalnum(*s) || *s=='_') ++s;
      return *s=='=';
}

#ifndef __U_BOOT__
/* the src parameter allows us to peek forward to a possible &n syntax
 * for file descriptor duplication, e.g., "2>&1".
 * Return code is 0 normally, 1 if a syntax error is detected in src.
 * Resource errors (in xmalloc) cause the process to exit */
static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
      struct in_str *input)
{
      struct child_prog *child=ctx->child;
      struct redir_struct *redir = child->redirects;
      struct redir_struct *last_redir=NULL;

      /* Create a new redir_struct and drop it onto the end of the linked list */
      while(redir) {
            last_redir=redir;
            redir=redir->next;
      }
      redir = xmalloc(sizeof(struct redir_struct));
      redir->next=NULL;
      redir->word.gl_pathv=NULL;
      if (last_redir) {
            last_redir->next=redir;
      } else {
            child->redirects=redir;
      }

      redir->type=style;
      redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;

      debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);

      /* Check for a '2>&1' type redirect */
      redir->dup = redirect_dup_num(input);
      if (redir->dup == -2) return 1;  /* syntax error */
      if (redir->dup != -1) {
            /* Erik had a check here that the file descriptor in question
             * is legit; I postpone that to "run time"
             * A "-" representation of "close me" shows up as a -3 here */
            debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
      } else {
            /* We do _not_ try to open the file that src points to,
             * since we need to return and let src be expanded first.
             * Set ctx->pending_redirect, so we know what to do at the
             * end of the next parsed word.
             */
            ctx->pending_redirect = redir;
      }
      return 0;
}
#endif

struct pipe *new_pipe(void) {
      struct pipe *pi;
      pi = xmalloc(sizeof(struct pipe));
      pi->num_progs = 0;
      pi->progs = NULL;
      pi->next = NULL;
      pi->followup = 0;  /* invalid */
      pi->r_mode = RES_NONE;
      return pi;
}

static void initialize_context(struct p_context *ctx)
{
      ctx->pipe=NULL;
#ifndef __U_BOOT__
      ctx->pending_redirect=NULL;
#endif
      ctx->child=NULL;
      ctx->list_head=new_pipe();
      ctx->pipe=ctx->list_head;
      ctx->w=RES_NONE;
      ctx->stack=NULL;
#ifdef __U_BOOT__
      ctx->old_flag=0;
#endif
      done_command(ctx);   /* creates the memory for working child */
}

/* normal return is 0
 * if a reserved word is found, and processed, return 1
 * should handle if, then, elif, else, fi, for, while, until, do, done.
 * case, function, and select are obnoxious, save those for later.
 */
struct reserved_combo {
      char *literal;
      int code;
      long flag;
};
/* Mostly a list of accepted follow-up reserved words.
 * FLAG_END means we are done with the sequence, and are ready
 * to turn the compound list into a command.
 * FLAG_START means the word must start a new compound list.
 */
static struct reserved_combo reserved_list[] = {
      { "if",    RES_IF,    FLAG_THEN | FLAG_START },
      { "then",  RES_THEN,  FLAG_ELIF | FLAG_ELSE | FLAG_FI },
      { "elif",  RES_ELIF,  FLAG_THEN },
      { "else",  RES_ELSE,  FLAG_FI   },
      { "fi",    RES_FI,    FLAG_END  },
      { "for",   RES_FOR,   FLAG_IN   | FLAG_START },
      { "while", RES_WHILE, FLAG_DO   | FLAG_START },
      { "until", RES_UNTIL, FLAG_DO   | FLAG_START },
      { "in",    RES_IN,    FLAG_DO   },
      { "do",    RES_DO,    FLAG_DONE },
      { "done",  RES_DONE,  FLAG_END  }
};
#define NRES (sizeof(reserved_list)/sizeof(struct reserved_combo))

int reserved_word(o_string *dest, struct p_context *ctx)
{
      struct reserved_combo *r;
      for (r=reserved_list;
            r<reserved_list+NRES; r++) {
            if (strcmp(dest->data, r->literal) == 0) {
                  debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
                  if (r->flag & FLAG_START) {
                        struct p_context *new = xmalloc(sizeof(struct p_context));
                        debug_printf("push stack\n");
                        if (ctx->w == RES_IN || ctx->w == RES_FOR) {
                              syntax();
                              free(new);
                              ctx->w = RES_SNTX;
                              b_reset(dest);
                              return 1;
                        }
                        *new = *ctx;   /* physical copy */
                        initialize_context(ctx);
                        ctx->stack=new;
                  } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
                        syntax();
                        ctx->w = RES_SNTX;
                        b_reset(dest);
                        return 1;
                  }
                  ctx->w=r->code;
                  ctx->old_flag = r->flag;
                  if (ctx->old_flag & FLAG_END) {
                        struct p_context *old;
                        debug_printf("pop stack\n");
                        done_pipe(ctx,PIPE_SEQ);
                        old = ctx->stack;
                        old->child->group = ctx->list_head;
#ifndef __U_BOOT__
                        old->child->subshell = 0;
#endif
                        *ctx = *old;   /* physical copy */
                        free(old);
                  }
                  b_reset (dest);
                  return 1;
            }
      }
      return 0;
}

/* normal return is 0.
 * Syntax or xglob errors return 1. */
static int done_word(o_string *dest, struct p_context *ctx)
{
      struct child_prog *child=ctx->child;
#ifndef __U_BOOT__
      glob_t *glob_target;
      int gr, flags = 0;
#else
      char *str, *s;
      int argc, cnt;
#endif

      debug_printf("done_word: %s %p\n", dest->data, child);
      if (dest->length == 0 && !dest->nonnull) {
            debug_printf("  true null, ignored\n");
            return 0;
      }
#ifndef __U_BOOT__
      if (ctx->pending_redirect) {
            glob_target = &ctx->pending_redirect->word;
      } else {
#endif
            if (child->group) {
                  syntax();
                  return 1;  /* syntax error, groups and arglists don't mix */
            }
            if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) {
                  debug_printf("checking %s for reserved-ness\n",dest->data);
                  if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
            }
#ifndef __U_BOOT__
            glob_target = &child->glob_result;
            if (child->argv) flags |= GLOB_APPEND;
#else
            for (cnt = 1, s = dest->data; s && *s; s++) {
                  if (*s == '\\') s++;
                  cnt++;
            }
            str = malloc(cnt);
            if (!str) return 1;
            if ( child->argv == NULL) {
                  child->argc=0;
            }
            argc = ++child->argc;
            child->argv = realloc(child->argv, (argc+1)*sizeof(*child->argv));
            if (child->argv == NULL) return 1;
            child->argv[argc-1]=str;
            child->argv[argc]=NULL;
            for (s = dest->data; s && *s; s++,str++) {
                  if (*s == '\\') s++;
                  *str = *s;
            }
            *str = '\0';
#endif
#ifndef __U_BOOT__
      }
      gr = xglob(dest, flags, glob_target);
      if (gr != 0) return 1;
#endif

      b_reset(dest);
#ifndef __U_BOOT__
      if (ctx->pending_redirect) {
            ctx->pending_redirect=NULL;
            if (glob_target->gl_pathc != 1) {
                  error_msg("ambiguous redirect");
                  return 1;
            }
      } else {
            child->argv = glob_target->gl_pathv;
      }
#endif
      if (ctx->w == RES_FOR) {
            done_word(dest,ctx);
            done_pipe(ctx,PIPE_SEQ);
      }
      return 0;
}

/* The only possible error here is out of memory, in which case
 * xmalloc exits. */
static int done_command(struct p_context *ctx)
{
      /* The child is really already in the pipe structure, so
       * advance the pipe counter and make a new, null child.
       * Only real trickiness here is that the uncommitted
       * child structure, to which ctx->child points, is not
       * counted in pi->num_progs. */
      struct pipe *pi=ctx->pipe;
      struct child_prog *prog=ctx->child;

      if (prog && prog->group == NULL
             && prog->argv == NULL
#ifndef __U_BOOT__
             && prog->redirects == NULL) {
#else
                                                            ) {
#endif
            debug_printf("done_command: skipping null command\n");
            return 0;
      } else if (prog) {
            pi->num_progs++;
            debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
      } else {
            debug_printf("done_command: initializing\n");
      }
      pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));

      prog = pi->progs + pi->num_progs;
#ifndef __U_BOOT__
      prog->redirects = NULL;
#endif
      prog->argv = NULL;
#ifndef __U_BOOT__
      prog->is_stopped = 0;
#endif
      prog->group = NULL;
#ifndef __U_BOOT__
      prog->glob_result.gl_pathv = NULL;
      prog->family = pi;
#endif
      prog->sp = 0;
      ctx->child = prog;
      prog->type = ctx->type;

      /* but ctx->pipe and ctx->list_head remain unchanged */
      return 0;
}

static int done_pipe(struct p_context *ctx, pipe_style type)
{
      struct pipe *new_p;
      done_command(ctx);  /* implicit closure of previous command */
      debug_printf("done_pipe, type %d\n", type);
      ctx->pipe->followup = type;
      ctx->pipe->r_mode = ctx->w;
      new_p=new_pipe();
      ctx->pipe->next = new_p;
      ctx->pipe = new_p;
      ctx->child = NULL;
      done_command(ctx);  /* set up new pipe to accept commands */
      return 0;
}

#ifndef __U_BOOT__
/* peek ahead in the in_str to find out if we have a "&n" construct,
 * as in "2>&1", that represents duplicating a file descriptor.
 * returns either -2 (syntax error), -1 (no &), or the number found.
 */
static int redirect_dup_num(struct in_str *input)
{
      int ch, d=0, ok=0;
      ch = b_peek(input);
      if (ch != '&') return -1;

      b_getch(input);  /* get the & */
      ch=b_peek(input);
      if (ch == '-') {
            b_getch(input);
            return -3;  /* "-" represents "close me" */
      }
      while (isdigit(ch)) {
            d = d*10+(ch-'0');
            ok=1;
            b_getch(input);
            ch = b_peek(input);
      }
      if (ok) return d;

      error_msg("ambiguous redirect");
      return -2;
}

/* If a redirect is immediately preceded by a number, that number is
 * supposed to tell which file descriptor to redirect.  This routine
 * looks for such preceding numbers.  In an ideal world this routine
 * needs to handle all the following classes of redirects...
 *     echo 2>foo     # redirects fd  2 to file "foo", nothing passed to echo
 *     echo 49>foo    # redirects fd 49 to file "foo", nothing passed to echo
 *     echo -2>foo    # redirects fd  1 to file "foo",    "-2" passed to echo
 *     echo 49x>foo   # redirects fd  1 to file "foo",   "49x" passed to echo
 * A -1 output from this program means no valid number was found, so the
 * caller should use the appropriate default for this redirection.
 */
static int redirect_opt_num(o_string *o)
{
      int num;

      if (o->length==0) return -1;
      for(num=0; num<o->length; num++) {
            if (!isdigit(*(o->data+num))) {
                  return -1;
            }
      }
      /* reuse num (and save an int) */
      num=atoi(o->data);
      b_reset(o);
      return num;
}

FILE *generate_stream_from_list(struct pipe *head)
{
      FILE *pf;
#if 1
      int pid, channel[2];
      if (pipe(channel)<0) perror_msg_and_die("pipe");
      pid=fork();
      if (pid<0) {
            perror_msg_and_die("fork");
      } else if (pid==0) {
            close(channel[0]);
            if (channel[1] != 1) {
                  dup2(channel[1],1);
                  close(channel[1]);
            }
#if 0
#define SURROGATE "surrogate response"
            write(1,SURROGATE,sizeof(SURROGATE));
            _exit(run_list(head));
#else
            _exit(run_list_real(head));   /* leaks memory */
#endif
      }
      debug_printf("forked child %d\n",pid);
      close(channel[1]);
      pf = fdopen(channel[0],"r");
      debug_printf("pipe on FILE *%p\n",pf);
#else
      free_pipe_list(head,0);
      pf=popen("echo surrogate response","r");
      debug_printf("started fake pipe on FILE *%p\n",pf);
#endif
      return pf;
}

/* this version hacked for testing purposes */
/* return code is exit status of the process that is run. */
static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
{
      int retcode;
      o_string result=NULL_O_STRING;
      struct p_context inner;
      FILE *p;
      struct in_str pipe_str;
      initialize_context(&inner);

      /* recursion to generate command */
      retcode = parse_stream(&result, &inner, input, subst_end);
      if (retcode != 0) return retcode;  /* syntax error or EOF */
      done_word(&result, &inner);
      done_pipe(&inner, PIPE_SEQ);
      b_free(&result);

      p=generate_stream_from_list(inner.list_head);
      if (p==NULL) return 1;
      mark_open(fileno(p));
      setup_file_in_str(&pipe_str, p);

      /* now send results of command back into original context */
      retcode = parse_stream(dest, ctx, &pipe_str, '\0');
      /* XXX In case of a syntax error, should we try to kill the child?
       * That would be tough to do right, so just read until EOF. */
      if (retcode == 1) {
            while (b_getch(&pipe_str)!=EOF) { /* discard */ };
      }

      debug_printf("done reading from pipe, pclose()ing\n");
      /* This is the step that wait()s for the child.  Should be pretty
       * safe, since we just read an EOF from its stdout.  We could try
       * to better, by using wait(), and keeping track of background jobs
       * at the same time.  That would be a lot of work, and contrary
       * to the KISS philosophy of this program. */
      mark_closed(fileno(p));
      retcode=pclose(p);
      free_pipe_list(inner.list_head,0);
      debug_printf("pclosed, retcode=%d\n",retcode);
      /* XXX this process fails to trim a single trailing newline */
      return retcode;
}

static int parse_group(o_string *dest, struct p_context *ctx,
      struct in_str *input, int ch)
{
      int rcode, endch=0;
      struct p_context sub;
      struct child_prog *child = ctx->child;
      if (child->argv) {
            syntax();
            return 1;  /* syntax error, groups and arglists don't mix */
      }
      initialize_context(&sub);
      switch(ch) {
            case '(': endch=')'; child->subshell=1; break;
            case '{': endch='}'; break;
            default: syntax();   /* really logic error */
      }
      rcode=parse_stream(dest,&sub,input,endch);
      done_word(dest,&sub); /* finish off the final word in the subcontext */
      done_pipe(&sub, PIPE_SEQ);  /* and the final command there, too */
      child->group = sub.list_head;
      return rcode;
      /* child remains "open", available for possible redirects */
}
#endif

/* basically useful version until someone wants to get fancier,
 * see the bash man page under "Parameter Expansion" */
static char *lookup_param(char *src)
{
      char *p;

      if (!src)
            return NULL;

            p = getenv(src);
            if (!p)
                  p = get_local_var(src);

      return p;
}

#ifdef __U_BOOT__
static char *get_dollar_var(char ch)
{
      static char buf[40];

      buf[0] = '\0';
      switch (ch) {
            case '?':
                  sprintf(buf, "%u", (unsigned int)last_return_code);
                  break;
            default:
                  return NULL;
      }
      return buf;
}
#endif

/* return code: 0 for OK, 1 for syntax error */
static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
{
#ifndef __U_BOOT__
      int i, advance=0;
#else
      int advance=0;
#endif
#ifndef __U_BOOT__
      char sep[]=" ";
#endif
      int ch = input->peek(input);  /* first character after the $ */
      debug_printf("handle_dollar: ch=%c\n",ch);
      if (isalpha(ch)) {
            b_addchr(dest, SPECIAL_VAR_SYMBOL);
            ctx->child->sp++;
            while(ch=b_peek(input),isalnum(ch) || ch=='_') {
                  b_getch(input);
                  b_addchr(dest,ch);
            }
            b_addchr(dest, SPECIAL_VAR_SYMBOL);
#ifndef __U_BOOT__
      } else if (isdigit(ch)) {
            i = ch-'0';  /* XXX is $0 special? */
            if (i<global_argc) {
                  parse_string(dest, ctx, global_argv[i]); /* recursion */
            }
            advance = 1;
#endif
      } else switch (ch) {
#ifndef __U_BOOT__
            case '$':
                  b_adduint(dest,getpid());
                  advance = 1;
                  break;
            case '!':
                  if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
                  advance = 1;
                  break;
#endif
            case '?':
#ifndef __U_BOOT__
                  b_adduint(dest,last_return_code);
#else
                  ctx->child->sp++;
                  b_addchr(dest, SPECIAL_VAR_SYMBOL);
                  b_addchr(dest, '$');
                  b_addchr(dest, '?');
                  b_addchr(dest, SPECIAL_VAR_SYMBOL);
#endif
                  advance = 1;
                  break;
#ifndef __U_BOOT__
            case '#':
                  b_adduint(dest,global_argc ? global_argc-1 : 0);
                  advance = 1;
                  break;
#endif
            case '{':
                  b_addchr(dest, SPECIAL_VAR_SYMBOL);
                  ctx->child->sp++;
                  b_getch(input);
                  /* XXX maybe someone will try to escape the '}' */
                  while(ch=b_getch(input),ch!=EOF && ch!='}') {
                        b_addchr(dest,ch);
                  }
                  if (ch != '}') {
                        syntax();
                        return 1;
                  }
                  b_addchr(dest, SPECIAL_VAR_SYMBOL);
                  break;
#ifndef __U_BOOT__
            case '(':
                  b_getch(input);
                  process_command_subs(dest, ctx, input, ')');
                  break;
            case '*':
                  sep[0]=ifs[0];
                  for (i=1; i<global_argc; i++) {
                        parse_string(dest, ctx, global_argv[i]);
                        if (i+1 < global_argc) parse_string(dest, ctx, sep);
                  }
                  break;
            case '@':
            case '-':
            case '_':
                  /* still unhandled, but should be eventually */
                  error_msg("unhandled syntax: $%c",ch);
                  return 1;
                  break;
#endif
            default:
                  b_addqchr(dest,'$',dest->quote);
      }
      /* Eat the character if the flag was set.  If the compiler
       * is smart enough, we could substitute "b_getch(input);"
       * for all the "advance = 1;" above, and also end up with
       * a nice size-optimized program.  Hah!  That'll be the day.
       */
      if (advance) b_getch(input);
      return 0;
}

#ifndef __U_BOOT__
int parse_string(o_string *dest, struct p_context *ctx, const char *src)
{
      struct in_str foo;
      setup_string_in_str(&foo, src);
      return parse_stream(dest, ctx, &foo, '\0');
}
#endif

/* return code is 0 for normal exit, 1 for syntax error */
int parse_stream(o_string *dest, struct p_context *ctx,
      struct in_str *input, int end_trigger)
{
      unsigned int ch, m;
#ifndef __U_BOOT__
      int redir_fd;
      redir_type redir_style;
#endif
      int next;

      /* Only double-quote state is handled in the state variable dest->quote.
       * A single-quote triggers a bypass of the main loop until its mate is
       * found.  When recursing, quote state is passed in via dest->quote. */

      debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
      while ((ch=b_getch(input))!=EOF) {
            m = map[ch];
#ifdef __U_BOOT__
            if (input->__promptme == 0) return 1;
#endif
            next = (ch == '\n') ? 0 : b_peek(input);

            debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d - %c\n",
                  ch >= ' ' ? ch : '.', ch, m,
                  dest->quote, ctx->stack == NULL ? '*' : '.');

            if (m==0 || ((m==1 || m==2) && dest->quote)) {
                  b_addqchr(dest, ch, dest->quote);
            } else {
                  if (m==2) {  /* unquoted IFS */
                        if (done_word(dest, ctx)) {
                              return 1;
                        }
                        /* If we aren't performing a substitution, treat a newline as a
                         * command separator.  */
                        if (end_trigger != '\0' && ch=='\n')
                              done_pipe(ctx,PIPE_SEQ);
                  }
                  if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
                        debug_printf("leaving parse_stream (triggered)\n");
                        return 0;
                  }
#if 0
                  if (ch=='\n') {
                        /* Yahoo!  Time to run with it! */
                        done_pipe(ctx,PIPE_SEQ);
                        run_list(ctx->list_head);
                        initialize_context(ctx);
                  }
#endif
                  if (m!=2) switch (ch) {
            case '#':
                  if (dest->length == 0 && !dest->quote) {
                        while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
                  } else {
                        b_addqchr(dest, ch, dest->quote);
                  }
                  break;
            case '\\':
                  if (next == EOF) {
                        syntax();
                        return 1;
                  }
                  b_addqchr(dest, '\\', dest->quote);
                  b_addqchr(dest, b_getch(input), dest->quote);
                  break;
            case '$':
                  if (handle_dollar(dest, ctx, input)!=0) return 1;
                  break;
            case '\'':
                  dest->nonnull = 1;
                  while(ch=b_getch(input),ch!=EOF && ch!='\'') {
#ifdef __U_BOOT__
                        if(input->__promptme == 0) return 1;
#endif
                        b_addchr(dest,ch);
                  }
                  if (ch==EOF) {
                        syntax();
                        return 1;
                  }
                  break;
            case '"':
                  dest->nonnull = 1;
                  dest->quote = !dest->quote;
                  break;
#ifndef __U_BOOT__
            case '`':
                  process_command_subs(dest, ctx, input, '`');
                  break;
            case '>':
                  redir_fd = redirect_opt_num(dest);
                  done_word(dest, ctx);
                  redir_style=REDIRECT_OVERWRITE;
                  if (next == '>') {
                        redir_style=REDIRECT_APPEND;
                        b_getch(input);
                  } else if (next == '(') {
                        syntax();   /* until we support >(list) Process Substitution */
                        return 1;
                  }
                  setup_redirect(ctx, redir_fd, redir_style, input);
                  break;
            case '<':
                  redir_fd = redirect_opt_num(dest);
                  done_word(dest, ctx);
                  redir_style=REDIRECT_INPUT;
                  if (next == '<') {
                        redir_style=REDIRECT_HEREIS;
                        b_getch(input);
                  } else if (next == '>') {
                        redir_style=REDIRECT_IO;
                        b_getch(input);
                  } else if (next == '(') {
                        syntax();   /* until we support <(list) Process Substitution */
                        return 1;
                  }
                  setup_redirect(ctx, redir_fd, redir_style, input);
                  break;
#endif
            case ';':
                  done_word(dest, ctx);
                  done_pipe(ctx,PIPE_SEQ);
                  break;
            case '&':
                  done_word(dest, ctx);
                  if (next=='&') {
                        b_getch(input);
                        done_pipe(ctx,PIPE_AND);
                  } else {
#ifndef __U_BOOT__
                        done_pipe(ctx,PIPE_BG);
#else
                        syntax_err();
                        return 1;
#endif
                  }
                  break;
            case '|':
                  done_word(dest, ctx);
                  if (next=='|') {
                        b_getch(input);
                        done_pipe(ctx,PIPE_OR);
                  } else {
                        /* we could pick up a file descriptor choice here
                         * with redirect_opt_num(), but bash doesn't do it.
                         * "echo foo 2| cat" yields "foo 2". */
#ifndef __U_BOOT__
                        done_command(ctx);
#else
                        syntax_err();
                        return 1;
#endif
                  }
                  break;
#ifndef __U_BOOT__
            case '(':
            case '{':
                  if (parse_group(dest, ctx, input, ch)!=0) return 1;
                  break;
            case ')':
            case '}':
                  syntax();   /* Proper use of this character caught by end_trigger */
                  return 1;
                  break;
#endif
            default:
                  syntax();   /* this is really an internal logic error */
                  return 1;
                  }
            }
      }
      /* complain if quote?  No, maybe we just finished a command substitution
       * that was quoted.  Example:
       * $ echo "`cat foo` plus more"
       * and we just got the EOF generated by the subshell that ran "cat foo"
       * The only real complaint is if we got an EOF when end_trigger != '\0',
       * that is, we were really supposed to get end_trigger, and never got
       * one before the EOF.  Can't use the standard "syntax error" return code,
       * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
      debug_printf("leaving parse_stream (EOF)\n");
      if (end_trigger != '\0') return -1;
      return 0;
}

void mapset(const unsigned char *set, int code)
{
      const unsigned char *s;
      for (s=set; *s; s++) map[*s] = code;
}

void update_ifs_map(void)
{
      /* char *ifs and char map[256] are both globals. */
      ifs = (uchar *)getenv("IFS");
      if (ifs == NULL) ifs=(uchar *)" \t\n";
      /* Precompute a list of 'flow through' behavior so it can be treated
       * quickly up front.  Computation is necessary because of IFS.
       * Special case handling of IFS == " \t\n" is not implemented.
       * The map[] array only really needs two bits each, and on most machines
       * that would be faster because of the reduced L1 cache footprint.
       */
      memset(map,0,sizeof(map)); /* most characters flow through always */
#ifndef __U_BOOT__
      mapset((uchar *)"\\$'\"`", 3);      /* never flow through */
      mapset((uchar *)"<>;&|(){}#", 1);   /* flow through if quoted */
#else
      mapset((uchar *)"\\$'\"", 3);       /* never flow through */
      mapset((uchar *)";&|#", 1);         /* flow through if quoted */
#endif
      mapset(ifs, 2);            /* also flow through if quoted */
}

/* most recursion does not come through here, the exeception is
 * from builtin_source() */
int parse_stream_outer(struct in_str *inp, int flag)
{

      struct p_context ctx;
      o_string temp=NULL_O_STRING;
      int rcode;
#ifdef __U_BOOT__
      int code = 0;
#endif
      do {
            ctx.type = flag;
            initialize_context(&ctx);
            update_ifs_map();
            if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING)) mapset((uchar *)";$&|", 0);
            inp->promptmode=1;
            rcode = parse_stream(&temp, &ctx, inp, '\n');
#ifdef __U_BOOT__
            if (rcode == 1) flag_repeat = 0;
#endif
            if (rcode != 1 && ctx.old_flag != 0) {
                  syntax();
#ifdef __U_BOOT__
                  flag_repeat = 0;
#endif
            }
            if (rcode != 1 && ctx.old_flag == 0) {
                  done_word(&temp, &ctx);
                  done_pipe(&ctx,PIPE_SEQ);
#ifndef __U_BOOT__
                  run_list(ctx.list_head);
#else
                  code = run_list(ctx.list_head);
                  if (code == -2) { /* exit */
                        b_free(&temp);
                        code = 0;
                        /* XXX hackish way to not allow exit from main loop */
                        if (inp->peek == file_peek) {
                              printf("exit not allowed from main input shell.\n");
                              continue;
                        }
                        break;
                  }
                  if (code == -1)
                      flag_repeat = 0;
#endif
            } else {
                  if (ctx.old_flag != 0) {
                        free(ctx.stack);
                        b_reset(&temp);
                  }
#ifdef __U_BOOT__
                  if (inp->__promptme == 0) printf("<INTERRUPT>\n");
                  inp->__promptme = 1;
#endif
                  temp.nonnull = 0;
                  temp.quote = 0;
                  inp->p = NULL;
                  free_pipe_list(ctx.list_head,0);
            }
            b_free(&temp);
      } while (rcode != -1 && !(flag & FLAG_EXIT_FROM_LOOP));   /* loop on syntax errors, return on EOF */
#ifndef __U_BOOT__
      return 0;
#else
      return (code != 0) ? 1 : 0;
#endif /* __U_BOOT__ */
}

#ifndef __U_BOOT__
static int parse_string_outer(const char *s, int flag)
#else
int parse_string_outer(char *s, int flag)
#endif      /* __U_BOOT__ */
{
      struct in_str input;
#ifdef __U_BOOT__
      char *p = NULL;
      int rcode;
      if ( !s || !*s)
            return 1;
      if (!(p = strchr(s, '\n')) || *++p) {
            p = xmalloc(strlen(s) + 2);
            strcpy(p, s);
            strcat(p, "\n");
            setup_string_in_str(&input, p);
            rcode = parse_stream_outer(&input, flag);
            free(p);
            return rcode;
      } else {
#endif
      setup_string_in_str(&input, s);
      return parse_stream_outer(&input, flag);
#ifdef __U_BOOT__
      }
#endif
}

#ifndef __U_BOOT__
static int parse_file_outer(FILE *f)
#else
int parse_file_outer(void)
#endif
{
      int rcode;
      struct in_str input;
#ifndef __U_BOOT__
      setup_file_in_str(&input, f);
#else
      setup_file_in_str(&input);
#endif
      rcode = parse_stream_outer(&input, FLAG_PARSE_SEMICOLON);
      return rcode;
}

#ifdef __U_BOOT__
#ifndef CONFIG_RELOC_FIXUP_WORKS
static void u_boot_hush_reloc(void)
{
      unsigned long addr;
      struct reserved_combo *r;

      for (r=reserved_list; r<reserved_list+NRES; r++) {
            addr = (ulong) (r->literal) + gd->reloc_off;
            r->literal = (char *)addr;
      }
}
#endif

int u_boot_hush_start(void)
{
      if (top_vars == NULL) {
            top_vars = malloc(sizeof(struct variables));
            top_vars->name = "HUSH_VERSION";
            top_vars->value = "0.01";
            top_vars->next = 0;
            top_vars->flg_export = 0;
            top_vars->flg_read_only = 1;
#ifndef CONFIG_RELOC_FIXUP_WORKS
            u_boot_hush_reloc();
#endif
      }
      return 0;
}

static void *xmalloc(size_t size)
{
      void *p = NULL;

      if (!(p = malloc(size))) {
          printf("ERROR : memory not allocated\n");
          for(;;);
      }
      return p;
}

static void *xrealloc(void *ptr, size_t size)
{
      void *p = NULL;

      if (!(p = realloc(ptr, size))) {
          printf("ERROR : memory not allocated\n");
          for(;;);
      }
      return p;
}
#endif /* __U_BOOT__ */

#ifndef __U_BOOT__
/* Make sure we have a controlling tty.  If we get started under a job
 * aware app (like bash for example), make sure we are now in charge so
 * we don't fight over who gets the foreground */
static void setup_job_control(void)
{
      static pid_t shell_pgrp;
      /* Loop until we are in the foreground.  */
      while (tcgetpgrp (shell_terminal) != (shell_pgrp = getpgrp ()))
            kill (- shell_pgrp, SIGTTIN);

      /* Ignore interactive and job-control signals.  */
      signal(SIGINT, SIG_IGN);
      signal(SIGQUIT, SIG_IGN);
      signal(SIGTERM, SIG_IGN);
      signal(SIGTSTP, SIG_IGN);
      signal(SIGTTIN, SIG_IGN);
      signal(SIGTTOU, SIG_IGN);
      signal(SIGCHLD, SIG_IGN);

      /* Put ourselves in our own process group.  */
      setsid();
      shell_pgrp = getpid ();
      setpgid (shell_pgrp, shell_pgrp);

      /* Grab control of the terminal.  */
      tcsetpgrp(shell_terminal, shell_pgrp);
}

int hush_main(int argc, char * const *argv)
{
      int opt;
      FILE *input;
      char **e = environ;

      /* XXX what should these be while sourcing /etc/profile? */
      global_argc = argc;
      global_argv = argv;

      /* (re?) initialize globals.  Sometimes hush_main() ends up calling
       * hush_main(), therefore we cannot rely on the BSS to zero out this
       * stuff.  Reset these to 0 every time. */
      ifs = NULL;
      /* map[] is taken care of with call to update_ifs_map() */
      fake_mode = 0;
      interactive = 0;
      close_me_head = NULL;
      last_bg_pid = 0;
      job_list = NULL;
      last_jobid = 0;

      /* Initialize some more globals to non-zero values */
      set_cwd();
#ifdef CONFIG_FEATURE_COMMAND_EDITING
      cmdedit_set_initial_prompt();
#else
      PS1 = NULL;
#endif
      PS2 = "> ";

      /* initialize our shell local variables with the values
       * currently living in the environment */
      if (e) {
            for (; *e; e++)
                  set_local_var(*e, 2);   /* without call putenv() */
      }

      last_return_code=EXIT_SUCCESS;


      if (argv[0] && argv[0][0] == '-') {
            debug_printf("\nsourcing /etc/profile\n");
            if ((input = fopen("/etc/profile", "r")) != NULL) {
                  mark_open(fileno(input));
                  parse_file_outer(input);
                  mark_closed(fileno(input));
                  fclose(input);
            }
      }
      input=stdin;

      while ((opt = getopt(argc, argv, "c:xif")) > 0) {
            switch (opt) {
                  case 'c':
                        {
                              global_argv = argv+optind;
                              global_argc = argc-optind;
                              opt = parse_string_outer(optarg, FLAG_PARSE_SEMICOLON);
                              goto final_return;
                        }
                        break;
                  case 'i':
                        interactive++;
                        break;
                  case 'f':
                        fake_mode++;
                        break;
                  default:
#ifndef BB_VER
                        fprintf(stderr, "Usage: sh [FILE]...\n"
                                    "   or: sh -c command [args]...\n\n");
                        exit(EXIT_FAILURE);
#else
                        show_usage();
#endif
            }
      }
      /* A shell is interactive if the `-i' flag was given, or if all of
       * the following conditions are met:
       *      no -c command
       *    no arguments remaining or the -s flag given
       *    standard input is a terminal
       *    standard output is a terminal
       *    Refer to Posix.2, the description of the `sh' utility. */
      if (argv[optind]==NULL && input==stdin &&
                  isatty(fileno(stdin)) && isatty(fileno(stdout))) {
            interactive++;
      }

      debug_printf("\ninteractive=%d\n", interactive);
      if (interactive) {
            /* Looks like they want an interactive shell */
#ifndef CONFIG_FEATURE_SH_EXTRA_QUIET
            printf( "\n\n" BB_BANNER " hush - the humble shell v0.01 (testing)\n");
            printf( "Enter 'help' for a list of built-in commands.\n\n");
#endif
            setup_job_control();
      }

      if (argv[optind]==NULL) {
            opt=parse_file_outer(stdin);
            goto final_return;
      }

      debug_printf("\nrunning script '%s'\n", argv[optind]);
      global_argv = argv+optind;
      global_argc = argc-optind;
      input = xfopen(argv[optind], "r");
      opt = parse_file_outer(input);

#ifdef CONFIG_FEATURE_CLEAN_UP
      fclose(input);
      if (cwd && cwd != unknown)
            free((char*)cwd);
      {
            struct variables *cur, *tmp;
            for(cur = top_vars; cur; cur = tmp) {
                  tmp = cur->next;
                  if (!cur->flg_read_only) {
                        free(cur->name);
                        free(cur->value);
                        free(cur);
                  }
            }
      }
#endif

final_return:
      return(opt?opt:last_return_code);
}
#endif

static char *insert_var_value(char *inp)
{
      int res_str_len = 0;
      int len;
      int done = 0;
      char *p, *p1, *res_str = NULL;

      while ((p = strchr(inp, SPECIAL_VAR_SYMBOL))) {
            if (p != inp) {
                  len = p - inp;
                  res_str = xrealloc(res_str, (res_str_len + len));
                  strncpy((res_str + res_str_len), inp, len);
                  res_str_len += len;
            }
            inp = ++p;
            p = strchr(inp, SPECIAL_VAR_SYMBOL);
            *p = '\0';
            if ((p1 = lookup_param(inp))) {
                  len = res_str_len + strlen(p1);
                  res_str = xrealloc(res_str, (1 + len));
                  strcpy((res_str + res_str_len), p1);
                  res_str_len = len;
            }
            *p = SPECIAL_VAR_SYMBOL;
            inp = ++p;
            done = 1;
      }
      if (done) {
            res_str = xrealloc(res_str, (1 + res_str_len + strlen(inp)));
            strcpy((res_str + res_str_len), inp);
            while ((p = strchr(res_str, '\n'))) {
                  *p = ' ';
            }
      }
      return (res_str == NULL) ? inp : res_str;
}

static char **make_list_in(char **inp, char *name)
{
      int len, i;
      int name_len = strlen(name);
      int n = 0;
      char **list;
      char *p1, *p2, *p3;

      /* create list of variable values */
      list = xmalloc(sizeof(*list));
      for (i = 0; inp[i]; i++) {
            p3 = insert_var_value(inp[i]);
            p1 = p3;
            while (*p1) {
                  if ((*p1 == ' ')) {
                        p1++;
                        continue;
                  }
                  if ((p2 = strchr(p1, ' '))) {
                        len = p2 - p1;
                  } else {
                        len = strlen(p1);
                        p2 = p1 + len;
                  }
                  /* we use n + 2 in realloc for list,because we add
                   * new element and then we will add NULL element */
                  list = xrealloc(list, sizeof(*list) * (n + 2));
                  list[n] = xmalloc(2 + name_len + len);
                  strcpy(list[n], name);
                  strcat(list[n], "=");
                  strncat(list[n], p1, len);
                  list[n++][name_len + len + 1] = '\0';
                  p1 = p2;
            }
            if (p3 != inp[i]) free(p3);
      }
      list[n] = NULL;
      return list;
}

/* Make new string for parser */
static char * make_string(char ** inp)
{
      char *p;
      char *str = NULL;
      int n;
      int len = 2;

      for (n = 0; inp[n]; n++) {
            p = insert_var_value(inp[n]);
            str = xrealloc(str, (len + strlen(p)));
            if (n) {
                  strcat(str, " ");
            } else {
                  *str = '\0';
            }
            strcat(str, p);
            len = strlen(str) + 3;
            if (p != inp[n]) free(p);
      }
      len = strlen(str);
      *(str + len) = '\n';
      *(str + len + 1) = '\0';
      return str;
}

#ifdef __U_BOOT__
int do_showvar (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
      int i, k;
      int rcode = 0;
      struct variables *cur;

      if (argc == 1) {        /* Print all env variables    */
            for (cur = top_vars; cur; cur = cur->next) {
                  printf ("%s=%s\n", cur->name, cur->value);
                  if (ctrlc ()) {
                        puts ("\n ** Abort\n");
                        return 1;
                  }
            }
            return 0;
      }
      for (i = 1; i < argc; ++i) {  /* print single env variables */
            char *name = argv[i];

            k = -1;
            for (cur = top_vars; cur; cur = cur->next) {
                  if(strcmp (cur->name, name) == 0) {
                        k = 0;
                        printf ("%s=%s\n", cur->name, cur->value);
                  }
                  if (ctrlc ()) {
                        puts ("\n ** Abort\n");
                        return 1;
                  }
            }
            if (k < 0) {
                  printf ("## Error: \"%s\" not defined\n", name);
                  rcode ++;
            }
      }
      return rcode;
}

U_BOOT_CMD(
      showvar, CONFIG_SYS_MAXARGS, 1,     do_showvar,
      "print local hushshell variables",
      "\n    - print values of all hushshell variables\n"
      "showvar name ...\n"
      "    - print value of hushshell variable 'name'"
);

#endif
/****************************************************************************/

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