shell/hush.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * sh.c -- a prototype Bourne shell grammar parser
   4  *      Intended to follow the original Thompson and Ritchie
   5  *      "small and simple is beautiful" philosophy, which
   6  *      incidentally is a good match to today's BusyBox.
   7  *
   8  * Copyright (C) 2000,2001  Larry Doolittle  <larry@doolittle.boa.org>
   9  *
  10  * Credits:
  11  *      The parser routines proper are all original material, first
  12  *      written Dec 2000 and Jan 2001 by Larry Doolittle.  The
  13  *      execution engine, the builtins, and much of the underlying
  14  *      support has been adapted from busybox-0.49pre's lash, which is
  15  *      Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  16  *      written by Erik Andersen <andersen@codepoet.org>.  That, in turn,
  17  *      is based in part on ladsh.c, by Michael K. Johnson and Erik W.
  18  *      Troan, which they placed in the public domain.  I don't know
  19  *      how much of the Johnson/Troan code has survived the repeated
  20  *      rewrites.
  21  *
  22  * Other credits:
  23  *      simple_itoa() was lifted from boa-0.93.15
  24  *      b_addchr() derived from similar w_addchar function in glibc-2.2
  25  *      setup_redirect(), redirect_opt_num(), and big chunks of main()
  26  *        and many builtins derived from contributions by Erik Andersen
  27  *      miscellaneous bugfixes from Matt Kraai
  28  *
  29  * There are two big (and related) architecture differences between
  30  * this parser and the lash parser.  One is that this version is
  31  * actually designed from the ground up to understand nearly all
  32  * of the Bourne grammar.  The second, consequential change is that
  33  * the parser and input reader have been turned inside out.  Now,
  34  * the parser is in control, and asks for input as needed.  The old
  35  * way had the input reader in control, and it asked for parsing to
  36  * take place as needed.  The new way makes it much easier to properly
  37  * handle the recursion implicit in the various substitutions, especially
  38  * across continuation lines.
  39  *
  40  * Bash grammar not implemented: (how many of these were in original sh?)
  41  *      $@ (those sure look like weird quoting rules)
  42  *      $_
  43  *      ! negation operator for pipes
  44  *      &> and >& redirection of stdout+stderr
  45  *      Brace Expansion
  46  *      Tilde Expansion
  47  *      fancy forms of Parameter Expansion
  48  *      aliases
  49  *      Arithmetic Expansion
  50  *      <(list) and >(list) Process Substitution
  51  *      reserved words: case, esac, select, function
  52  *      Here Documents ( << word )
  53  *      Functions
  54  * Major bugs:
  55  *      job handling woefully incomplete and buggy
  56  *      reserved word execution woefully incomplete and buggy
  57  * to-do:
  58  *      port selected bugfixes from post-0.49 busybox lash - done?
  59  *      finish implementing reserved words: for, while, until, do, done
  60  *      change { and } from special chars to reserved words
  61  *      builtins: break, continue, eval, return, set, trap, ulimit
  62  *      test magic exec
  63  *      handle children going into background
  64  *      clean up recognition of null pipes
  65  *      check setting of global_argc and global_argv
  66  *      control-C handling, probably with longjmp
  67  *      follow IFS rules more precisely, including update semantics
  68  *      figure out what to do with backslash-newline
  69  *      explain why we use signal instead of sigaction
  70  *      propagate syntax errors, die on resource errors?
  71  *      continuation lines, both explicit and implicit - done?
  72  *      memory leak finding and plugging - done?
  73  *      more testing, especially quoting rules and redirection
  74  *      document how quoting rules not precisely followed for variable assignments
  75  *      maybe change map[] to use 2-bit entries
  76  *      (eventually) remove all the printf's
  77  *
  78  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  79  */
  80
  81 #include "busybox.h"
  82 #include <ctype.h>     /* isalpha, isdigit */
  83 #include <unistd.h>    /* getpid */
  84 #include <stdlib.h>    /* getenv, atoi */
  85 #include <string.h>    /* strchr */
  86 #include <stdio.h>     /* popen etc. */
  87 #include <glob.h>      /* glob, of course */
  88 #include <stdarg.h>    /* va_list */
  89 #include <errno.h>
  90 #include <fcntl.h>
  91 #include <getopt.h>    /* should be pretty obvious */
  92
  93 #include <sys/stat.h>  /* ulimit */
  94 #include <sys/types.h>
  95 #include <sys/wait.h>
  96 #include <signal.h>
  97
  98 /* #include <dmalloc.h> */
  99 /* #define DEBUG_SHELL */
 100
 101 #include "cmdedit.h"
 102
 103 #define SPECIAL_VAR_SYMBOL 03
 104 #define FLAG_EXIT_FROM_LOOP 1
 105 #define FLAG_PARSE_SEMICOLON (1 << 1)           /* symbol ';' is special for parser */
 106 #define FLAG_REPARSING           (1 << 2)               /* >=2nd pass */
 107
 108 typedef enum {
 109         REDIRECT_INPUT     = 1,
 110         REDIRECT_OVERWRITE = 2,
 111         REDIRECT_APPEND    = 3,
 112         REDIRECT_HEREIS    = 4,
 113         REDIRECT_IO        = 5
 114 } redir_type;
 115
 116 /* The descrip member of this structure is only used to make debugging
 117  * output pretty */
 118 static const struct {int mode; int default_fd; const char *descrip;} redir_table[] = {
 119         { 0,                         0, "()" },
 120         { O_RDONLY,                  0, "<"  },
 121         { O_CREAT|O_TRUNC|O_WRONLY,  1, ">"  },
 122         { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
 123         { O_RDONLY,                 -1, "<<" },
 124         { O_RDWR,                    1, "<>" }
 125 };
 126
 127 typedef enum {
 128         PIPE_SEQ = 1,
 129         PIPE_AND = 2,
 130         PIPE_OR  = 3,
 131         PIPE_BG  = 4,
 132 } pipe_style;
 133
 134 /* might eventually control execution */
 135 typedef enum {
 136         RES_NONE  = 0,
 137         RES_IF    = 1,
 138         RES_THEN  = 2,
 139         RES_ELIF  = 3,
 140         RES_ELSE  = 4,
 141         RES_FI    = 5,
 142         RES_FOR   = 6,
 143         RES_WHILE = 7,
 144         RES_UNTIL = 8,
 145         RES_DO    = 9,
 146         RES_DONE  = 10,
 147         RES_XXXX  = 11,
 148         RES_IN    = 12,
 149         RES_SNTX  = 13
 150 } reserved_style;
 151 #define FLAG_END   (1<<RES_NONE)
 152 #define FLAG_IF    (1<<RES_IF)
 153 #define FLAG_THEN  (1<<RES_THEN)
 154 #define FLAG_ELIF  (1<<RES_ELIF)
 155 #define FLAG_ELSE  (1<<RES_ELSE)
 156 #define FLAG_FI    (1<<RES_FI)
 157 #define FLAG_FOR   (1<<RES_FOR)
 158 #define FLAG_WHILE (1<<RES_WHILE)
 159 #define FLAG_UNTIL (1<<RES_UNTIL)
 160 #define FLAG_DO    (1<<RES_DO)
 161 #define FLAG_DONE  (1<<RES_DONE)
 162 #define FLAG_IN    (1<<RES_IN)
 163 #define FLAG_START (1<<RES_XXXX)
 164
 165 /* This holds pointers to the various results of parsing */
 166 struct p_context {
 167         struct child_prog *child;
 168         struct pipe *list_head;
 169         struct pipe *pipe;
 170         struct redir_struct *pending_redirect;
 171         reserved_style w;
 172         int old_flag;                           /* for figuring out valid reserved words */
 173         struct p_context *stack;
 174         int type;                       /* define type of parser : ";$" common or special symbol */
 175         /* How about quoting status? */
 176 };
 177
 178 struct redir_struct {
 179         redir_type type;                        /* type of redirection */
 180         int fd;                                         /* file descriptor being redirected */
 181         int dup;                                        /* -1, or file descriptor being duplicated */
 182         struct redir_struct *next;      /* pointer to the next redirect in the list */
 183         glob_t word;                            /* *word.gl_pathv is the filename */
 184 };
 185
 186 struct child_prog {
 187         pid_t pid;                                      /* 0 if exited */
 188         char **argv;                            /* program name and arguments */
 189         struct pipe *group;                     /* if non-NULL, first in group or subshell */
 190         int subshell;                           /* flag, non-zero if group must be forked */
 191         struct redir_struct *redirects; /* I/O redirections */
 192         glob_t glob_result;                     /* result of parameter globbing */
 193         int is_stopped;                         /* is the program currently running? */
 194         struct pipe *family;            /* pointer back to the child's parent pipe */
 195         int sp;                         /* number of SPECIAL_VAR_SYMBOL */
 196         int type;
 197 };
 198
 199 struct pipe {
 200         int jobid;                                      /* job number */
 201         int num_progs;                          /* total number of programs in job */
 202         int running_progs;                      /* number of programs running */
 203         char *text;                                     /* name of job */
 204         char *cmdbuf;                           /* buffer various argv's point into */
 205         pid_t pgrp;                                     /* process group ID for the job */
 206         struct child_prog *progs;       /* array of commands in pipe */
 207         struct pipe *next;                      /* to track background commands */
 208         int stopped_progs;                      /* number of programs alive, but stopped */
 209         int job_context;                        /* bitmask defining current context */
 210         pipe_style followup;            /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
 211         reserved_style r_mode;          /* supports if, for, while, until */
 212 };
 213
 214 struct close_me {
 215         int fd;
 216         struct close_me *next;
 217 };
 218
 219 struct variables {
 220         char *name;
 221         char *value;
 222         int flg_export;
 223         int flg_read_only;
 224         struct variables *next;
 225 };
 226
 227 /* globals, connect us to the outside world
 228  * the first three support $?, $#, and $1 */
 229 static char **global_argv;
 230 static int global_argc;
 231 static int last_return_code;
 232 extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
 233
 234 /* "globals" within this file */
 235 static char *ifs;
 236 static unsigned char map[256];
 237 static int fake_mode;
 238 static int interactive;
 239 static struct close_me *close_me_head;
 240 static const char *cwd;
 241 static struct pipe *job_list;
 242 static unsigned int last_bg_pid;
 243 static int last_jobid;
 244 static unsigned int shell_terminal;
 245 static char *PS1;
 246 static char *PS2;
 247 static struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
 248 static struct variables *top_vars = &shell_ver;
 249
 250
 251 #define B_CHUNK (100)
 252 #define B_NOSPAC 1
 253
 254 typedef struct {
 255         char *data;
 256         int length;
 257         int maxlen;
 258         int quote;
 259         int nonnull;
 260 } o_string;
 261 #define NULL_O_STRING {NULL,0,0,0,0}
 262 /* used for initialization:
 263         o_string foo = NULL_O_STRING; */
 264
 265 /* I can almost use ordinary FILE *.  Is open_memstream() universally
 266  * available?  Where is it documented? */
 267 struct in_str {
 268         const char *p;
 269         char peek_buf[2];
 270         int __promptme;
 271         int promptmode;
 272         FILE *file;
 273         int (*get) (struct in_str *);
 274         int (*peek) (struct in_str *);
 275 };
 276 #define b_getch(input) ((input)->get(input))
 277 #define b_peek(input) ((input)->peek(input))
 278
 279 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
 280
 281 struct built_in_command {
 282         const char *cmd;                        /* name */
 283         const char *descr;                      /* description */
 284         int (*function) (struct child_prog *);  /* function ptr */
 285 };
 286
 287 /* belongs in busybox.h */
 288 static int max(int a, int b) {
 289         return (a>b)?a:b;
 290 }
 291
 292 /* This should be in utility.c */
 293 #ifdef DEBUG_SHELL
 294 static void debug_printf(const char *format, ...)
 295 {
 296         va_list args;
 297         va_start(args, format);
 298         vfprintf(stderr, format, args);
 299         va_end(args);
 300 }
 301 /* broken, of course, but OK for testing */
 302 static char *indenter(int i)
 303 {
 304         static char blanks[]="                                    ";
 305         return &blanks[sizeof(blanks)-i-1];
 306 }
 307 #else
 308 #define debug_printf(...) do {;} while(0);
 309 #endif
 310 #define final_printf debug_printf
 311
 312 static void __syntax(char *file, int line) {
 313         bb_error_msg("syntax error %s:%d", file, line);
 314 }
 315 #define syntax() __syntax(__FILE__, __LINE__)
 316
 317 /* Index of subroutines: */
 318 /*   function prototypes for builtins */
 319 static int builtin_cd(struct child_prog *child);
 320 static int builtin_env(struct child_prog *child);
 321 static int builtin_eval(struct child_prog *child);
 322 static int builtin_exec(struct child_prog *child);
 323 static int builtin_exit(struct child_prog *child);
 324 static int builtin_export(struct child_prog *child);
 325 static int builtin_fg_bg(struct child_prog *child);
 326 static int builtin_help(struct child_prog *child);
 327 static int builtin_jobs(struct child_prog *child);
 328 static int builtin_pwd(struct child_prog *child);
 329 static int builtin_read(struct child_prog *child);
 330 static int builtin_set(struct child_prog *child);
 331 static int builtin_shift(struct child_prog *child);
 332 static int builtin_source(struct child_prog *child);
 333 static int builtin_umask(struct child_prog *child);
 334 static int builtin_unset(struct child_prog *child);
 335 static int builtin_not_written(struct child_prog *child);
 336 /*   o_string manipulation: */
 337 static int b_check_space(o_string *o, int len);
 338 static int b_addchr(o_string *o, int ch);
 339 static void b_reset(o_string *o);
 340 static int b_addqchr(o_string *o, int ch, int quote);
 341 static int b_adduint(o_string *o, unsigned int i);
 342 /*  in_str manipulations: */
 343 static int static_get(struct in_str *i);
 344 static int static_peek(struct in_str *i);
 345 static int file_get(struct in_str *i);
 346 static int file_peek(struct in_str *i);
 347 static void setup_file_in_str(struct in_str *i, FILE *f);
 348 static void setup_string_in_str(struct in_str *i, const char *s);
 349 /*  close_me manipulations: */
 350 static void mark_open(int fd);
 351 static void mark_closed(int fd);
 352 static void close_all(void);
 353 /*  "run" the final data structures: */
 354 static int free_pipe_list(struct pipe *head, int indent);
 355 static int free_pipe(struct pipe *pi, int indent);
 356 /*  really run the final data structures: */
 357 static int setup_redirects(struct child_prog *prog, int squirrel[]);
 358 static int run_list_real(struct pipe *pi);
 359 static void pseudo_exec(struct child_prog *child) ATTRIBUTE_NORETURN;
 360 static int run_pipe_real(struct pipe *pi);
 361 /*   extended glob support: */
 362 static int globhack(const char *src, int flags, glob_t *pglob);
 363 static int glob_needed(const char *s);
 364 static int xglob(o_string *dest, int flags, glob_t *pglob);
 365 /*   variable assignment: */
 366 static int is_assignment(const char *s);
 367 /*   data structure manipulation: */
 368 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
 369 static void initialize_context(struct p_context *ctx);
 370 static int done_word(o_string *dest, struct p_context *ctx);
 371 static int done_command(struct p_context *ctx);
 372 static int done_pipe(struct p_context *ctx, pipe_style type);
 373 /*   primary string parsing: */
 374 static int redirect_dup_num(struct in_str *input);
 375 static int redirect_opt_num(o_string *o);
 376 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
 377 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
 378 static char *lookup_param(char *src);
 379 static char *make_string(char **inp);
 380 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
 381 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
 382 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
 383 /*   setup: */
 384 static int parse_stream_outer(struct in_str *inp, int flag);
 385 static int parse_string_outer(const char *s, int flag);
 386 static int parse_file_outer(FILE *f);
 387 /*   job management: */
 388 static int checkjobs(struct pipe* fg_pipe);
 389 static void insert_bg_job(struct pipe *pi);
 390 static void remove_bg_job(struct pipe *pi);
 391 /*     local variable support */
 392 static char **make_list_in(char **inp, char *name);
 393 static char *insert_var_value(char *inp);
 394 static char *get_local_var(const char *var);
 395 static void  unset_local_var(const char *name);
 396 static int set_local_var(const char *s, int flg_export);
 397
 398 /* Table of built-in functions.  They can be forked or not, depending on
 399  * context: within pipes, they fork.  As simple commands, they do not.
 400  * When used in non-forking context, they can change global variables
 401  * in the parent shell process.  If forked, of course they can not.
 402  * For example, 'unset foo | whatever' will parse and run, but foo will
 403  * still be set at the end. */
 404 static const struct built_in_command bltins[] = {
 405         {"bg", "Resume a job in the background", builtin_fg_bg},
 406         {"break", "Exit for, while or until loop", builtin_not_written},
 407         {"cd", "Change working directory", builtin_cd},
 408         {"continue", "Continue for, while or until loop", builtin_not_written},
 409         {"env", "Print all environment variables", builtin_env},
 410         {"eval", "Construct and run shell command", builtin_eval},
 411         {"exec", "Exec command, replacing this shell with the exec'd process",
 412                 builtin_exec},
 413         {"exit", "Exit from shell()", builtin_exit},
 414         {"export", "Set environment variable", builtin_export},
 415         {"fg", "Bring job into the foreground", builtin_fg_bg},
 416         {"jobs", "Lists the active jobs", builtin_jobs},
 417         {"pwd", "Print current directory", builtin_pwd},
 418         {"read", "Input environment variable", builtin_read},
 419         {"return", "Return from a function", builtin_not_written},
 420         {"set", "Set/unset shell local variables", builtin_set},
 421         {"shift", "Shift positional parameters", builtin_shift},
 422         {"trap", "Trap signals", builtin_not_written},
 423         {"ulimit","Controls resource limits", builtin_not_written},
 424         {"umask","Sets file creation mask", builtin_umask},
 425         {"unset", "Unset environment variable", builtin_unset},
 426         {".", "Source-in and run commands in a file", builtin_source},
 427         {"help", "List shell built-in commands", builtin_help},
 428         {NULL, NULL, NULL}
 429 };
 430
 431 static const char *set_cwd(void)
 432 {
 433         if(cwd==bb_msg_unknown)
 434                 cwd = NULL;     /* xgetcwd(arg) called free(arg) */
 435         cwd = xgetcwd((char *)cwd);
 436         if (!cwd)
 437                 cwd = bb_msg_unknown;
 438         return cwd;
 439 }
 440
 441 /* built-in 'eval' handler */
 442 static int builtin_eval(struct child_prog *child)
 443 {
 444         char *str = NULL;
 445         int rcode = EXIT_SUCCESS;
 446
 447         if (child->argv[1]) {
 448                 str = make_string(child->argv + 1);
 449                 parse_string_outer(str, FLAG_EXIT_FROM_LOOP |
 450                                         FLAG_PARSE_SEMICOLON);
 451                 free(str);
 452                 rcode = last_return_code;
 453         }
 454         return rcode;
 455 }
 456
 457 /* built-in 'cd <path>' handler */
 458 static int builtin_cd(struct child_prog *child)
 459 {
 460         char *newdir;
 461         if (child->argv[1] == NULL)
 462                 newdir = getenv("HOME");
 463         else
 464                 newdir = child->argv[1];
 465         if (chdir(newdir)) {
 466                 printf("cd: %s: %s\n", newdir, strerror(errno));
 467                 return EXIT_FAILURE;
 468         }
 469         set_cwd();
 470         return EXIT_SUCCESS;
 471 }
 472
 473 /* built-in 'env' handler */
 474 static int builtin_env(struct child_prog *dummy ATTRIBUTE_UNUSED)
 475 {
 476         char **e = environ;
 477         if (e == NULL) return EXIT_FAILURE;
 478         for (; *e; e++) {
 479                 puts(*e);
 480         }
 481         return EXIT_SUCCESS;
 482 }
 483
 484 /* built-in 'exec' handler */
 485 static int builtin_exec(struct child_prog *child)
 486 {
 487         if (child->argv[1] == NULL)
 488                 return EXIT_SUCCESS;   /* Really? */
 489         child->argv++;
 490         pseudo_exec(child);
 491         /* never returns */
 492 }
 493
 494 /* built-in 'exit' handler */
 495 static int builtin_exit(struct child_prog *child)
 496 {
 497         if (child->argv[1] == NULL)
 498                 exit(last_return_code);
 499         exit (atoi(child->argv[1]));
 500 }
 501
 502 /* built-in 'export VAR=value' handler */
 503 static int builtin_export(struct child_prog *child)
 504 {
 505         int res = 0;
 506         char *name = child->argv[1];
 507
 508         if (name == NULL) {
 509                 return (builtin_env(child));
 510         }
 511
 512         name = strdup(name);
 513
 514         if(name) {
 515                 char *value = strchr(name, '=');
 516
 517                 if (!value) {
 518                         char *tmp;
 519                         /* They are exporting something without an =VALUE */
 520
 521                         value = get_local_var(name);
 522                         if (value) {
 523                                 size_t ln = strlen(name);
 524
 525                                 tmp = realloc(name, ln+strlen(value)+2);
 526                                 if(tmp==NULL)
 527                                         res = -1;
 528                                 else {
 529                                         sprintf(tmp+ln, "=%s", value);
 530                                         name = tmp;
 531                                 }
 532                         } else {
 533                                 /* bash does not return an error when trying to export
 534                                  * an undefined variable.  Do likewise. */
 535                                 res = 1;
 536                         }
 537                 }
 538         }
 539         if (res<0)
 540                 bb_perror_msg("export");
 541         else if(res==0)
 542                 res = set_local_var(name, 1);
 543         else
 544                 res = 0;
 545         free(name);
 546         return res;
 547 }
 548
 549 /* built-in 'fg' and 'bg' handler */
 550 static int builtin_fg_bg(struct child_prog *child)
 551 {
 552         int i, jobnum;
 553         struct pipe *pi=NULL;
 554
 555         if (!interactive)
 556                 return EXIT_FAILURE;
 557         /* If they gave us no args, assume they want the last backgrounded task */
 558         if (!child->argv[1]) {
 559                 for (pi = job_list; pi; pi = pi->next) {
 560                         if (pi->jobid == last_jobid) {
 561                                 break;
 562                         }
 563                 }
 564                 if (!pi) {
 565                         bb_error_msg("%s: no current job", child->argv[0]);
 566                         return EXIT_FAILURE;
 567                 }
 568         } else {
 569                 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
 570                         bb_error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
 571                         return EXIT_FAILURE;
 572                 }
 573                 for (pi = job_list; pi; pi = pi->next) {
 574                         if (pi->jobid == jobnum) {
 575                                 break;
 576                         }
 577                 }
 578                 if (!pi) {
 579                         bb_error_msg("%s: %d: no such job", child->argv[0], jobnum);
 580                         return EXIT_FAILURE;
 581                 }
 582         }
 583
 584         if (*child->argv[0] == 'f') {
 585                 /* Put the job into the foreground.  */
 586                 tcsetpgrp(shell_terminal, pi->pgrp);
 587         }
 588
 589         /* Restart the processes in the job */
 590         for (i = 0; i < pi->num_progs; i++)
 591                 pi->progs[i].is_stopped = 0;
 592
 593         if ( (i=kill(- pi->pgrp, SIGCONT)) < 0) {
 594                 if (i == ESRCH) {
 595                         remove_bg_job(pi);
 596                 } else {
 597                         bb_perror_msg("kill (SIGCONT)");
 598                 }
 599         }
 600
 601         pi->stopped_progs = 0;
 602         return EXIT_SUCCESS;
 603 }
 604
 605 /* built-in 'help' handler */
 606 static int builtin_help(struct child_prog *dummy ATTRIBUTE_UNUSED)
 607 {
 608         const struct built_in_command *x;
 609
 610         printf("\nBuilt-in commands:\n");
 611         printf("-------------------\n");
 612         for (x = bltins; x->cmd; x++) {
 613                 if (x->descr==NULL)
 614                         continue;
 615                 printf("%s\t%s\n", x->cmd, x->descr);
 616         }
 617         printf("\n\n");
 618         return EXIT_SUCCESS;
 619 }
 620
 621 /* built-in 'jobs' handler */
 622 static int builtin_jobs(struct child_prog *child ATTRIBUTE_UNUSED)
 623 {
 624         struct pipe *job;
 625         char *status_string;
 626
 627         for (job = job_list; job; job = job->next) {
 628                 if (job->running_progs == job->stopped_progs)
 629                         status_string = "Stopped";
 630                 else
 631                         status_string = "Running";
 632
 633                 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
 634         }
 635         return EXIT_SUCCESS;
 636 }
 637
 638
 639 /* built-in 'pwd' handler */
 640 static int builtin_pwd(struct child_prog *dummy ATTRIBUTE_UNUSED)
 641 {
 642         puts(set_cwd());
 643         return EXIT_SUCCESS;
 644 }
 645
 646 /* built-in 'read VAR' handler */
 647 static int builtin_read(struct child_prog *child)
 648 {
 649         int res;
 650
 651         if (child->argv[1]) {
 652                 char string[BUFSIZ];
 653                 char *var = 0;
 654
 655                 string[0] = 0;  /* In case stdin has only EOF */
 656                 /* read string */
 657                 fgets(string, sizeof(string), stdin);
 658                 chomp(string);
 659                 var = malloc(strlen(child->argv[1])+strlen(string)+2);
 660                 if(var) {
 661                         sprintf(var, "%s=%s", child->argv[1], string);
 662                         res = set_local_var(var, 0);
 663                 } else
 664                         res = -1;
 665                 if (res)
 666                         bb_perror_msg("read");
 667                 free(var);      /* So not move up to avoid breaking errno */
 668                 return res;
 669         } else {
 670                 do res=getchar(); while(res!='\n' && res!=EOF);
 671                 return 0;
 672         }
 673 }
 674
 675 /* built-in 'set VAR=value' handler */
 676 static int builtin_set(struct child_prog *child)
 677 {
 678         char *temp = child->argv[1];
 679         struct variables *e;
 680
 681         if (temp == NULL)
 682                 for(e = top_vars; e; e=e->next)
 683                         printf("%s=%s\n", e->name, e->value);
 684         else
 685                 set_local_var(temp, 0);
 686
 687                 return EXIT_SUCCESS;
 688 }
 689
 690
 691 /* Built-in 'shift' handler */
 692 static int builtin_shift(struct child_prog *child)
 693 {
 694         int n=1;
 695         if (child->argv[1]) {
 696                 n=atoi(child->argv[1]);
 697         }
 698         if (n>=0 && n<global_argc) {
 699                 /* XXX This probably breaks $0 */
 700                 global_argc -= n;
 701                 global_argv += n;
 702                 return EXIT_SUCCESS;
 703         } else {
 704                 return EXIT_FAILURE;
 705         }
 706 }
 707
 708 /* Built-in '.' handler (read-in and execute commands from file) */
 709 static int builtin_source(struct child_prog *child)
 710 {
 711         FILE *input;
 712         int status;
 713
 714         if (child->argv[1] == NULL)
 715                 return EXIT_FAILURE;
 716
 717         /* XXX search through $PATH is missing */
 718         input = fopen(child->argv[1], "r");
 719         if (!input) {
 720                 bb_error_msg("Couldn't open file '%s'", child->argv[1]);
 721                 return EXIT_FAILURE;
 722         }
 723
 724         /* Now run the file */
 725         /* XXX argv and argc are broken; need to save old global_argv
 726          * (pointer only is OK!) on this stack frame,
 727          * set global_argv=child->argv+1, recurse, and restore. */
 728         mark_open(fileno(input));
 729         status = parse_file_outer(input);
 730         mark_closed(fileno(input));
 731         fclose(input);
 732         return (status);
 733 }
 734
 735 static int builtin_umask(struct child_prog *child)
 736 {
 737         mode_t new_umask;
 738         const char *arg = child->argv[1];
 739         char *end;
 740         if (arg) {
 741                 new_umask=strtoul(arg, &end, 8);
 742                 if (*end!='\0' || end == arg) {
 743                         return EXIT_FAILURE;
 744                 }
 745         } else {
 746                 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
 747         }
 748         umask(new_umask);
 749         return EXIT_SUCCESS;
 750 }
 751
 752 /* built-in 'unset VAR' handler */
 753 static int builtin_unset(struct child_prog *child)
 754 {
 755         /* bash returned already true */
 756         unset_local_var(child->argv[1]);
 757         return EXIT_SUCCESS;
 758 }
 759
 760 static int builtin_not_written(struct child_prog *child)
 761 {
 762         printf("builtin_%s not written\n",child->argv[0]);
 763         return EXIT_FAILURE;
 764 }
 765
 766 static int b_check_space(o_string *o, int len)
 767 {
 768         /* It would be easy to drop a more restrictive policy
 769          * in here, such as setting a maximum string length */
 770         if (o->length + len > o->maxlen) {
 771                 char *old_data = o->data;
 772                 /* assert (data == NULL || o->maxlen != 0); */
 773                 o->maxlen += max(2*len, B_CHUNK);
 774                 o->data = realloc(o->data, 1 + o->maxlen);
 775                 if (o->data == NULL) {
 776                         free(old_data);
 777                 }
 778         }
 779         return o->data == NULL;
 780 }
 781
 782 static int b_addchr(o_string *o, int ch)
 783 {
 784         debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
 785         if (b_check_space(o, 1)) return B_NOSPAC;
 786         o->data[o->length] = ch;
 787         o->length++;
 788         o->data[o->length] = '\0';
 789         return 0;
 790 }
 791
 792 static void b_reset(o_string *o)
 793 {
 794         o->length = 0;
 795         o->nonnull = 0;
 796         if (o->data != NULL) *o->data = '\0';
 797 }
 798
 799 static void b_free(o_string *o)
 800 {
 801         b_reset(o);
 802         free(o->data);
 803         o->data = NULL;
 804         o->maxlen = 0;
 805 }
 806
 807 /* My analysis of quoting semantics tells me that state information
 808  * is associated with a destination, not a source.
 809  */
 810 static int b_addqchr(o_string *o, int ch, int quote)
 811 {
 812         if (quote && strchr("*?[\\",ch)) {
 813                 int rc;
 814                 rc = b_addchr(o, '\\');
 815                 if (rc) return rc;
 816         }
 817         return b_addchr(o, ch);
 818 }
 819
 820 /* belongs in utility.c */
 821 static char *simple_itoa(unsigned int i)
 822 {
 823         /* 21 digits plus null terminator, good for 64-bit or smaller ints */
 824         static char local[22];
 825         char *p = &local[21];
 826         *p-- = '\0';
 827         do {
 828                 *p-- = '0' + i % 10;
 829                 i /= 10;
 830         } while (i > 0);
 831         return p + 1;
 832 }
 833
 834 static int b_adduint(o_string *o, unsigned int i)
 835 {
 836         int r;
 837         char *p = simple_itoa(i);
 838         /* no escape checking necessary */
 839         do r=b_addchr(o, *p++); while (r==0 && *p);
 840         return r;
 841 }
 842
 843 static int static_get(struct in_str *i)
 844 {
 845         int ch=*i->p++;
 846         if (ch=='\0') return EOF;
 847         return ch;
 848 }
 849
 850 static int static_peek(struct in_str *i)
 851 {
 852         return *i->p;
 853 }
 854
 855 static void cmdedit_set_initial_prompt(void)
 856 {
 857 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
 858         PS1 = NULL;
 859 #else
 860         PS1 = getenv("PS1");
 861         if(PS1==0)
 862                 PS1 = "\\w \\$ ";
 863 #endif
 864 }
 865
 866 static void setup_prompt_string(int promptmode, char **prompt_str)
 867 {
 868         debug_printf("setup_prompt_string %d ",promptmode);
 869 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
 870         /* Set up the prompt */
 871         if (promptmode == 1) {
 872                 free(PS1);
 873                 PS1=xmalloc(strlen(cwd)+4);
 874                 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
 875                 *prompt_str = PS1;
 876         } else {
 877                 *prompt_str = PS2;
 878         }
 879 #else
 880         *prompt_str = (promptmode==1)? PS1 : PS2;
 881 #endif
 882         debug_printf("result %s\n",*prompt_str);
 883 }
 884
 885 static void get_user_input(struct in_str *i)
 886 {
 887         char *prompt_str;
 888         static char the_command[BUFSIZ];
 889
 890         setup_prompt_string(i->promptmode, &prompt_str);
 891 #ifdef CONFIG_FEATURE_COMMAND_EDITING
 892         /*
 893          ** enable command line editing only while a command line
 894          ** is actually being read; otherwise, we'll end up bequeathing
 895          ** atexit() handlers and other unwanted stuff to our
 896          ** child processes (rob@sysgo.de)
 897          */
 898         cmdedit_read_input(prompt_str, the_command);
 899 #else
 900         fputs(prompt_str, stdout);
 901         fflush(stdout);
 902         the_command[0]=fgetc(i->file);
 903         the_command[1]='\0';
 904 #endif
 905         fflush(stdout);
 906         i->p = the_command;
 907 }
 908
 909 /* This is the magic location that prints prompts
 910  * and gets data back from the user */
 911 static int file_get(struct in_str *i)
 912 {
 913         int ch;
 914
 915         ch = 0;
 916         /* If there is data waiting, eat it up */
 917         if (i->p && *i->p) {
 918                 ch=*i->p++;
 919         } else {
 920                 /* need to double check i->file because we might be doing something
 921                  * more complicated by now, like sourcing or substituting. */
 922                 if (i->__promptme && interactive && i->file == stdin) {
 923                         while(! i->p || (interactive && strlen(i->p)==0) ) {
 924                                 get_user_input(i);
 925                         }
 926                         i->promptmode=2;
 927                         i->__promptme = 0;
 928                         if (i->p && *i->p) {
 929                                 ch=*i->p++;
 930                         }
 931                 } else {
 932                         ch = fgetc(i->file);
 933                 }
 934
 935                 debug_printf("b_getch: got a %d\n", ch);
 936         }
 937         if (ch == '\n') i->__promptme=1;
 938         return ch;
 939 }
 940
 941 /* All the callers guarantee this routine will never be
 942  * used right after a newline, so prompting is not needed.
 943  */
 944 static int file_peek(struct in_str *i)
 945 {
 946         if (i->p && *i->p) {
 947                 return *i->p;
 948         } else {
 949                 i->peek_buf[0] = fgetc(i->file);
 950                 i->peek_buf[1] = '\0';
 951                 i->p = i->peek_buf;
 952                 debug_printf("b_peek: got a %d\n", *i->p);
 953                 return *i->p;
 954         }
 955 }
 956
 957 static void setup_file_in_str(struct in_str *i, FILE *f)
 958 {
 959         i->peek = file_peek;
 960         i->get = file_get;
 961         i->__promptme=1;
 962         i->promptmode=1;
 963         i->file = f;
 964         i->p = NULL;
 965 }
 966
 967 static void setup_string_in_str(struct in_str *i, const char *s)
 968 {
 969         i->peek = static_peek;
 970         i->get = static_get;
 971         i->__promptme=1;
 972         i->promptmode=1;
 973         i->p = s;
 974 }
 975
 976 static void mark_open(int fd)
 977 {
 978         struct close_me *new = xmalloc(sizeof(struct close_me));
 979         new->fd = fd;
 980         new->next = close_me_head;
 981         close_me_head = new;
 982 }
 983
 984 static void mark_closed(int fd)
 985 {
 986         struct close_me *tmp;
 987         if (close_me_head == NULL || close_me_head->fd != fd)
 988                 bb_error_msg_and_die("corrupt close_me");
 989         tmp = close_me_head;
 990         close_me_head = close_me_head->next;
 991         free(tmp);
 992 }
 993
 994 static void close_all(void)
 995 {
 996         struct close_me *c;
 997         for (c=close_me_head; c; c=c->next) {
 998                 close(c->fd);
 999         }
1000         close_me_head = NULL;
1001 }
1002
1003 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
1004  * and stderr if they are redirected. */
1005 static int setup_redirects(struct child_prog *prog, int squirrel[])
1006 {
1007         int openfd, mode;
1008         struct redir_struct *redir;
1009
1010         for (redir=prog->redirects; redir; redir=redir->next) {
1011                 if (redir->dup == -1 && redir->word.gl_pathv == NULL) {
1012                         /* something went wrong in the parse.  Pretend it didn't happen */
1013                         continue;
1014                 }
1015                 if (redir->dup == -1) {
1016                         mode=redir_table[redir->type].mode;
1017                         openfd = open(redir->word.gl_pathv[0], mode, 0666);
1018                         if (openfd < 0) {
1019                         /* this could get lost if stderr has been redirected, but
1020                            bash and ash both lose it as well (though zsh doesn't!) */
1021                                 bb_perror_msg("error opening %s", redir->word.gl_pathv[0]);
1022                                 return 1;
1023                         }
1024                 } else {
1025                         openfd = redir->dup;
1026                 }
1027
1028                 if (openfd != redir->fd) {
1029                         if (squirrel && redir->fd < 3) {
1030                                 squirrel[redir->fd] = dup(redir->fd);
1031                         }
1032                         if (openfd == -3) {
1033                                 close(openfd);
1034                         } else {
1035                                 dup2(openfd, redir->fd);
1036                                 if (redir->dup == -1)
1037                                         close (openfd);
1038                         }
1039                 }
1040         }
1041         return 0;
1042 }
1043
1044 static void restore_redirects(int squirrel[])
1045 {
1046         int i, fd;
1047         for (i=0; i<3; i++) {
1048                 fd = squirrel[i];
1049                 if (fd != -1) {
1050                         /* No error checking.  I sure wouldn't know what
1051                          * to do with an error if I found one! */
1052                         dup2(fd, i);
1053                         close(fd);
1054                 }
1055         }
1056 }
1057
1058 /* never returns */
1059 /* XXX no exit() here.  If you don't exec, use _exit instead.
1060  * The at_exit handlers apparently confuse the calling process,
1061  * in particular stdin handling.  Not sure why? */
1062 static void pseudo_exec(struct child_prog *child)
1063 {
1064         int i, rcode;
1065         char *p;
1066         const struct built_in_command *x;
1067         if (child->argv) {
1068                 for (i=0; is_assignment(child->argv[i]); i++) {
1069                         debug_printf("pid %d environment modification: %s\n",getpid(),child->argv[i]);
1070                         p = insert_var_value(child->argv[i]);
1071                         putenv(strdup(p));
1072                         if (p != child->argv[i]) free(p);
1073                 }
1074                 child->argv+=i;  /* XXX this hack isn't so horrible, since we are about
1075                                         to exit, and therefore don't need to keep data
1076                                         structures consistent for free() use. */
1077                 /* If a variable is assigned in a forest, and nobody listens,
1078                  * was it ever really set?
1079                  */
1080                 if (child->argv[0] == NULL) {
1081                         _exit(EXIT_SUCCESS);
1082                 }
1083
1084                 /*
1085                  * Check if the command matches any of the builtins.
1086                  * Depending on context, this might be redundant.  But it's
1087                  * easier to waste a few CPU cycles than it is to figure out
1088                  * if this is one of those cases.
1089                  */
1090                 for (x = bltins; x->cmd; x++) {
1091                         if (strcmp(child->argv[0], x->cmd) == 0 ) {
1092                                 debug_printf("builtin exec %s\n", child->argv[0]);
1093                                 rcode = x->function(child);
1094                                 fflush(stdout);
1095                                 _exit(rcode);
1096                         }
1097                 }
1098
1099                 /* Check if the command matches any busybox internal commands
1100                  * ("applets") here.
1101                  * FIXME: This feature is not 100% safe, since
1102                  * BusyBox is not fully reentrant, so we have no guarantee the things
1103                  * from the .bss are still zeroed, or that things from .data are still
1104                  * at their defaults.  We could exec ourself from /proc/self/exe, but I
1105                  * really dislike relying on /proc for things.  We could exec ourself
1106                  * from global_argv[0], but if we are in a chroot, we may not be able
1107                  * to find ourself... */
1108 #ifdef CONFIG_FEATURE_SH_STANDALONE_SHELL
1109                 {
1110                         int argc_l;
1111                         char** argv_l=child->argv;
1112                         char *name = child->argv[0];
1113
1114                         /* Count argc for use in a second... */
1115                         for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1116                         optind = 1;
1117                         debug_printf("running applet %s\n", name);
1118                         run_applet_by_name(name, argc_l, child->argv);
1119                 }
1120 #endif
1121                 debug_printf("exec of %s\n",child->argv[0]);
1122                 execvp(child->argv[0],child->argv);
1123                 bb_perror_msg("couldn't exec: %s",child->argv[0]);
1124                 _exit(1);
1125         } else if (child->group) {
1126                 debug_printf("runtime nesting to group\n");
1127                 interactive=0;    /* crucial!!!! */
1128                 rcode = run_list_real(child->group);
1129                 /* OK to leak memory by not calling free_pipe_list,
1130                  * since this process is about to exit */
1131                 _exit(rcode);
1132         } else {
1133                 /* Can happen.  See what bash does with ">foo" by itself. */
1134                 debug_printf("trying to pseudo_exec null command\n");
1135                 _exit(EXIT_SUCCESS);
1136         }
1137 }
1138
1139 static void insert_bg_job(struct pipe *pi)
1140 {
1141         struct pipe *thejob;
1142
1143         /* Linear search for the ID of the job to use */
1144         pi->jobid = 1;
1145         for (thejob = job_list; thejob; thejob = thejob->next)
1146                 if (thejob->jobid >= pi->jobid)
1147                         pi->jobid = thejob->jobid + 1;
1148
1149         /* add thejob to the list of running jobs */
1150         if (!job_list) {
1151                 thejob = job_list = xmalloc(sizeof(*thejob));
1152         } else {
1153                 for (thejob = job_list; thejob->next; thejob = thejob->next) /* nothing */;
1154                 thejob->next = xmalloc(sizeof(*thejob));
1155                 thejob = thejob->next;
1156         }
1157
1158         /* physically copy the struct job */
1159         memcpy(thejob, pi, sizeof(struct pipe));
1160         thejob->next = NULL;
1161         thejob->running_progs = thejob->num_progs;
1162         thejob->stopped_progs = 0;
1163         thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */
1164
1165         //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1166         {
1167                 char *bar=thejob->text;
1168                 char **foo=pi->progs[0].argv;
1169                 while(foo && *foo) {
1170                         bar += sprintf(bar, "%s ", *foo++);
1171                 }
1172         }
1173
1174         /* we don't wait for background thejobs to return -- append it
1175            to the list of backgrounded thejobs and leave it alone */
1176         printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1177         last_bg_pid = thejob->progs[0].pid;
1178         last_jobid = thejob->jobid;
1179 }
1180
1181 /* remove a backgrounded job */
1182 static void remove_bg_job(struct pipe *pi)
1183 {
1184         struct pipe *prev_pipe;
1185
1186         if (pi == job_list) {
1187                 job_list = pi->next;
1188         } else {
1189                 prev_pipe = job_list;
1190                 while (prev_pipe->next != pi)
1191                         prev_pipe = prev_pipe->next;
1192                 prev_pipe->next = pi->next;
1193         }
1194         if (job_list)
1195                 last_jobid = job_list->jobid;
1196         else
1197                 last_jobid = 0;
1198
1199         pi->stopped_progs = 0;
1200         free_pipe(pi, 0);
1201         free(pi);
1202 }
1203
1204 /* Checks to see if any processes have exited -- if they
1205    have, figure out why and see if a job has completed */
1206 static int checkjobs(struct pipe* fg_pipe)
1207 {
1208         int attributes;
1209         int status;
1210         int prognum = 0;
1211         struct pipe *pi;
1212         pid_t childpid;
1213
1214         attributes = WUNTRACED;
1215         if (fg_pipe==NULL) {
1216                 attributes |= WNOHANG;
1217         }
1218
1219         while ((childpid = waitpid(-1, &status, attributes)) > 0) {
1220                 if (fg_pipe) {
1221                         int i, rcode = 0;
1222                         for (i=0; i < fg_pipe->num_progs; i++) {
1223                                 if (fg_pipe->progs[i].pid == childpid) {
1224                                         if (i==fg_pipe->num_progs-1)
1225                                                 rcode=WEXITSTATUS(status);
1226                                         (fg_pipe->num_progs)--;
1227                                         return(rcode);
1228                                 }
1229                         }
1230                 }
1231
1232                 for (pi = job_list; pi; pi = pi->next) {
1233                         prognum = 0;
1234                         while (prognum < pi->num_progs && pi->progs[prognum].pid != childpid) {
1235                                 prognum++;
1236                         }
1237                         if (prognum < pi->num_progs)
1238                                 break;
1239                 }
1240
1241                 if(pi==NULL) {
1242                         debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
1243                         continue;
1244                 }
1245
1246                 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1247                         /* child exited */
1248                         pi->running_progs--;
1249                         pi->progs[prognum].pid = 0;
1250
1251                         if (!pi->running_progs) {
1252                                 printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
1253                                 remove_bg_job(pi);
1254                         }
1255                 } else {
1256                         /* child stopped */
1257                         pi->stopped_progs++;
1258                         pi->progs[prognum].is_stopped = 1;
1259                 }
1260         }
1261
1262         if (childpid == -1 && errno != ECHILD)
1263                 bb_perror_msg("waitpid");
1264
1265         /* move the shell to the foreground */
1266         //if (interactive && tcsetpgrp(shell_terminal, getpgid(0)))
1267         //      bb_perror_msg("tcsetpgrp-2");
1268         return -1;
1269 }
1270
1271 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1272  * to finish.  See checkjobs().
1273  *
1274  * return code is normally -1, when the caller has to wait for children
1275  * to finish to determine the exit status of the pipe.  If the pipe
1276  * is a simple builtin command, however, the action is done by the
1277  * time run_pipe_real returns, and the exit code is provided as the
1278  * return value.
1279  *
1280  * The input of the pipe is always stdin, the output is always
1281  * stdout.  The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1282  * because it tries to avoid running the command substitution in
1283  * subshell, when that is in fact necessary.  The subshell process
1284  * now has its stdout directed to the input of the appropriate pipe,
1285  * so this routine is noticeably simpler.
1286  */
1287 static int run_pipe_real(struct pipe *pi)
1288 {
1289         int i;
1290         int nextin, nextout;
1291         int pipefds[2];                         /* pipefds[0] is for reading */
1292         struct child_prog *child;
1293         const struct built_in_command *x;
1294         char *p;
1295
1296         nextin = 0;
1297         pi->pgrp = -1;
1298
1299         /* Check if this is a simple builtin (not part of a pipe).
1300          * Builtins within pipes have to fork anyway, and are handled in
1301          * pseudo_exec.  "echo foo | read bar" doesn't work on bash, either.
1302          */
1303         child = & (pi->progs[0]);
1304         if (pi->num_progs == 1 && child->group && child->subshell == 0) {
1305                 int squirrel[] = {-1, -1, -1};
1306                 int rcode;
1307                 debug_printf("non-subshell grouping\n");
1308                 setup_redirects(child, squirrel);
1309                 /* XXX could we merge code with following builtin case,
1310                  * by creating a pseudo builtin that calls run_list_real? */
1311                 rcode = run_list_real(child->group);
1312                 restore_redirects(squirrel);
1313                 return rcode;
1314         } else if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1315                 for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
1316                 if (i!=0 && child->argv[i]==NULL) {
1317                         /* assignments, but no command: set the local environment */
1318                         for (i=0; child->argv[i]!=NULL; i++) {
1319
1320                                 /* Ok, this case is tricky.  We have to decide if this is a
1321                                  * local variable, or an already exported variable.  If it is
1322                                  * already exported, we have to export the new value.  If it is
1323                                  * not exported, we need only set this as a local variable.
1324                                  * This junk is all to decide whether or not to export this
1325                                  * variable. */
1326                                 int export_me=0;
1327                                 char *name, *value;
1328                                 name = xstrdup(child->argv[i]);
1329                                 debug_printf("Local environment set: %s\n", name);
1330                                 value = strchr(name, '=');
1331                                 if (value)
1332                                         *value=0;
1333                                 if ( get_local_var(name)) {
1334                                         export_me=1;
1335                                 }
1336                                 free(name);
1337                                 p = insert_var_value(child->argv[i]);
1338                                 set_local_var(p, export_me);
1339                                 if (p != child->argv[i]) free(p);
1340                         }
1341                         return EXIT_SUCCESS;   /* don't worry about errors in set_local_var() yet */
1342                 }
1343                 for (i = 0; is_assignment(child->argv[i]); i++) {
1344                         p = insert_var_value(child->argv[i]);
1345                         putenv(strdup(p));
1346                         if (p != child->argv[i]) {
1347                                 child->sp--;
1348                                 free(p);
1349                         }
1350                 }
1351                 if (child->sp) {
1352                         char * str = NULL;
1353
1354                         str = make_string((child->argv + i));
1355                         parse_string_outer(str, FLAG_EXIT_FROM_LOOP | FLAG_REPARSING);
1356                         free(str);
1357                         return last_return_code;
1358                 }
1359                 for (x = bltins; x->cmd; x++) {
1360                         if (strcmp(child->argv[i], x->cmd) == 0 ) {
1361                                 int squirrel[] = {-1, -1, -1};
1362                                 int rcode;
1363                                 if (x->function == builtin_exec && child->argv[i+1]==NULL) {
1364                                         debug_printf("magic exec\n");
1365                                         setup_redirects(child,NULL);
1366                                         return EXIT_SUCCESS;
1367                                 }
1368                                 debug_printf("builtin inline %s\n", child->argv[0]);
1369                                 /* XXX setup_redirects acts on file descriptors, not FILEs.
1370                                  * This is perfect for work that comes after exec().
1371                                  * Is it really safe for inline use?  Experimentally,
1372                                  * things seem to work with glibc. */
1373                                 setup_redirects(child, squirrel);
1374                                 child->argv+=i;  /* XXX horrible hack */
1375                                 rcode = x->function(child);
1376                                 child->argv-=i;  /* XXX restore hack so free() can work right */
1377                                 restore_redirects(squirrel);
1378                                 return rcode;
1379                         }
1380                 }
1381         }
1382
1383         for (i = 0; i < pi->num_progs; i++) {
1384                 child = & (pi->progs[i]);
1385
1386                 /* pipes are inserted between pairs of commands */
1387                 if ((i + 1) < pi->num_progs) {
1388                         if (pipe(pipefds)<0) bb_perror_msg_and_die("pipe");
1389                         nextout = pipefds[1];
1390                 } else {
1391                         nextout=1;
1392                         pipefds[0] = -1;
1393                 }
1394
1395                 /* XXX test for failed fork()? */
1396 #if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
1397                 if (!(child->pid = fork()))
1398 #else
1399                 if (!(child->pid = vfork()))
1400 #endif
1401                 {
1402                         /* Set the handling for job control signals back to the default.  */
1403                         signal(SIGINT, SIG_DFL);
1404                         signal(SIGQUIT, SIG_DFL);
1405                         signal(SIGTERM, SIG_DFL);
1406                         signal(SIGTSTP, SIG_DFL);
1407                         signal(SIGTTIN, SIG_DFL);
1408                         signal(SIGTTOU, SIG_DFL);
1409                         signal(SIGCHLD, SIG_DFL);
1410
1411                         close_all();
1412
1413                         if (nextin != 0) {
1414                                 dup2(nextin, 0);
1415                                 close(nextin);
1416                         }
1417                         if (nextout != 1) {
1418                                 dup2(nextout, 1);
1419                                 close(nextout);
1420                         }
1421                         if (pipefds[0]!=-1) {
1422                                 close(pipefds[0]);  /* opposite end of our output pipe */
1423                         }
1424
1425                         /* Like bash, explicit redirects override pipes,
1426                          * and the pipe fd is available for dup'ing. */
1427                         setup_redirects(child,NULL);
1428
1429                         if (interactive && pi->followup!=PIPE_BG) {
1430                                 /* If we (the child) win the race, put ourselves in the process
1431                                  * group whose leader is the first process in this pipe. */
1432                                 if (pi->pgrp < 0) {
1433                                         pi->pgrp = getpid();
1434                                 }
1435                                 if (setpgid(0, pi->pgrp) == 0) {
1436                                         tcsetpgrp(2, pi->pgrp);
1437                                 }
1438                         }
1439
1440                         pseudo_exec(child);
1441                 }
1442
1443
1444                 /* put our child in the process group whose leader is the
1445                    first process in this pipe */
1446                 if (pi->pgrp < 0) {
1447                         pi->pgrp = child->pid;
1448                 }
1449                 /* Don't check for errors.  The child may be dead already,
1450                  * in which case setpgid returns error code EACCES. */
1451                 setpgid(child->pid, pi->pgrp);
1452
1453                 if (nextin != 0)
1454                         close(nextin);
1455                 if (nextout != 1)
1456                         close(nextout);
1457
1458                 /* If there isn't another process, nextin is garbage
1459                    but it doesn't matter */
1460                 nextin = pipefds[0];
1461         }
1462         return -1;
1463 }
1464
1465 static int run_list_real(struct pipe *pi)
1466 {
1467         char *save_name = NULL;
1468         char **list = NULL;
1469         char **save_list = NULL;
1470         struct pipe *rpipe;
1471         int flag_rep = 0;
1472         int save_num_progs;
1473         int rcode=0, flag_skip=1;
1474         int flag_restore = 0;
1475         int if_code=0, next_if_code=0;  /* need double-buffer to handle elif */
1476         reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1477         /* check syntax for "for" */
1478         for (rpipe = pi; rpipe; rpipe = rpipe->next) {
1479                 if ((rpipe->r_mode == RES_IN ||
1480                     rpipe->r_mode == RES_FOR) &&
1481                     (rpipe->next == NULL)) {
1482                                 syntax();
1483                                 return 1;
1484                 }
1485                 if ((rpipe->r_mode == RES_IN &&
1486                         (rpipe->next->r_mode == RES_IN &&
1487                         rpipe->next->progs->argv != NULL))||
1488                         (rpipe->r_mode == RES_FOR &&
1489                         rpipe->next->r_mode != RES_IN)) {
1490                                 syntax();
1491                                 return 1;
1492                 }
1493         }
1494         for (; pi; pi = (flag_restore != 0) ? rpipe : pi->next) {
1495                 if (pi->r_mode == RES_WHILE || pi->r_mode == RES_UNTIL ||
1496                         pi->r_mode == RES_FOR) {
1497                                 flag_restore = 0;
1498                                 if (!rpipe) {
1499                                         flag_rep = 0;
1500                                         rpipe = pi;
1501                                 }
1502                 }
1503                 rmode = pi->r_mode;
1504                 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);
1505                 if (rmode == skip_more_in_this_rmode && flag_skip) {
1506                         if (pi->followup == PIPE_SEQ) flag_skip=0;
1507                         continue;
1508                 }
1509                 flag_skip = 1;
1510                 skip_more_in_this_rmode = RES_XXXX;
1511                 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1512                 if (rmode == RES_THEN &&  if_code) continue;
1513                 if (rmode == RES_ELSE && !if_code) continue;
1514                 if (rmode == RES_ELIF && !if_code) break;
1515                 if (rmode == RES_FOR && pi->num_progs) {
1516                         if (!list) {
1517                                 /* if no variable values after "in" we skip "for" */
1518                                 if (!pi->next->progs->argv) continue;
1519                                 /* create list of variable values */
1520                                 list = make_list_in(pi->next->progs->argv,
1521                                         pi->progs->argv[0]);
1522                                 save_list = list;
1523                                 save_name = pi->progs->argv[0];
1524                                 pi->progs->argv[0] = NULL;
1525                                 flag_rep = 1;
1526                         }
1527                         if (!(*list)) {
1528                                 free(pi->progs->argv[0]);
1529                                 free(save_list);
1530                                 list = NULL;
1531                                 flag_rep = 0;
1532                                 pi->progs->argv[0] = save_name;
1533                                 pi->progs->glob_result.gl_pathv[0] =
1534                                         pi->progs->argv[0];
1535                                 continue;
1536                         } else {
1537                                 /* insert new value from list for variable */
1538                                 if (pi->progs->argv[0])
1539                                         free(pi->progs->argv[0]);
1540                                 pi->progs->argv[0] = *list++;
1541                                 pi->progs->glob_result.gl_pathv[0] =
1542                                         pi->progs->argv[0];
1543                         }
1544                 }
1545                 if (rmode == RES_IN) continue;
1546                 if (rmode == RES_DO) {
1547                         if (!flag_rep) continue;
1548                 }
1549                 if ((rmode == RES_DONE)) {
1550                         if (flag_rep) {
1551                                 flag_restore = 1;
1552                         } else {
1553                                 rpipe = NULL;
1554                         }
1555                 }
1556                 if (pi->num_progs == 0) continue;
1557                 save_num_progs = pi->num_progs; /* save number of programs */
1558                 rcode = run_pipe_real(pi);
1559                 debug_printf("run_pipe_real returned %d\n",rcode);
1560                 if (rcode!=-1) {
1561                         /* We only ran a builtin: rcode was set by the return value
1562                          * of run_pipe_real(), and we don't need to wait for anything. */
1563                 } else if (pi->followup==PIPE_BG) {
1564                         /* XXX check bash's behavior with nontrivial pipes */
1565                         /* XXX compute jobid */
1566                         /* XXX what does bash do with attempts to background builtins? */
1567                         insert_bg_job(pi);
1568                         rcode = EXIT_SUCCESS;
1569                 } else {
1570                         if (interactive) {
1571                                 /* move the new process group into the foreground */
1572                                 if (tcsetpgrp(shell_terminal, pi->pgrp) && errno != ENOTTY)
1573                                         bb_perror_msg("tcsetpgrp-3");
1574                                 rcode = checkjobs(pi);
1575                                 /* move the shell to the foreground */
1576                                 if (tcsetpgrp(shell_terminal, getpgid(0)) && errno != ENOTTY)
1577                                         bb_perror_msg("tcsetpgrp-4");
1578                         } else {
1579                                 rcode = checkjobs(pi);
1580                         }
1581                         debug_printf("checkjobs returned %d\n",rcode);
1582                 }
1583                 last_return_code=rcode;
1584                 pi->num_progs = save_num_progs; /* restore number of programs */
1585                 if ( rmode == RES_IF || rmode == RES_ELIF )
1586                         next_if_code=rcode;  /* can be overwritten a number of times */
1587                 if (rmode == RES_WHILE)
1588                         flag_rep = !last_return_code;
1589                 if (rmode == RES_UNTIL)
1590                         flag_rep = last_return_code;
1591                 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1592                      (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1593                         skip_more_in_this_rmode=rmode;
1594                 checkjobs(NULL);
1595         }
1596         return rcode;
1597 }
1598
1599 /* return code is the exit status of the pipe */
1600 static int free_pipe(struct pipe *pi, int indent)
1601 {
1602         char **p;
1603         struct child_prog *child;
1604         struct redir_struct *r, *rnext;
1605         int a, i, ret_code=0;
1606
1607         if (pi->stopped_progs > 0)
1608                 return ret_code;
1609         final_printf("%s run pipe: (pid %d)\n",indenter(indent),getpid());
1610         for (i=0; i<pi->num_progs; i++) {
1611                 child = &pi->progs[i];
1612                 final_printf("%s  command %d:\n",indenter(indent),i);
1613                 if (child->argv) {
1614                         for (a=0,p=child->argv; *p; a++,p++) {
1615                                 final_printf("%s   argv[%d] = %s\n",indenter(indent),a,*p);
1616                         }
1617                         globfree(&child->glob_result);
1618                         child->argv=NULL;
1619                 } else if (child->group) {
1620                         final_printf("%s   begin group (subshell:%d)\n",indenter(indent), child->subshell);
1621                         ret_code = free_pipe_list(child->group,indent+3);
1622                         final_printf("%s   end group\n",indenter(indent));
1623                 } else {
1624                         final_printf("%s   (nil)\n",indenter(indent));
1625                 }
1626                 for (r=child->redirects; r; r=rnext) {
1627                         final_printf("%s   redirect %d%s", indenter(indent), r->fd, redir_table[r->type].descrip);
1628                         if (r->dup == -1) {
1629                                 /* guard against the case >$FOO, where foo is unset or blank */
1630                                 if (r->word.gl_pathv) {
1631                                         final_printf(" %s\n", *r->word.gl_pathv);
1632                                         globfree(&r->word);
1633                                 }
1634                         } else {
1635                                 final_printf("&%d\n", r->dup);
1636                         }
1637                         rnext=r->next;
1638                         free(r);
1639                 }
1640                 child->redirects=NULL;
1641         }
1642         free(pi->progs);   /* children are an array, they get freed all at once */
1643         pi->progs=NULL;
1644         return ret_code;
1645 }
1646
1647 static int free_pipe_list(struct pipe *head, int indent)
1648 {
1649         int rcode=0;   /* if list has no members */
1650         struct pipe *pi, *next;
1651         for (pi=head; pi; pi=next) {
1652                 final_printf("%s pipe reserved mode %d\n", indenter(indent), pi->r_mode);
1653                 rcode = free_pipe(pi, indent);
1654                 final_printf("%s pipe followup code %d\n", indenter(indent), pi->followup);
1655                 next=pi->next;
1656                 pi->next=NULL;
1657                 free(pi);
1658         }
1659         return rcode;
1660 }
1661
1662 /* Select which version we will use */
1663 static int run_list(struct pipe *pi)
1664 {
1665         int rcode=0;
1666         if (fake_mode==0) {
1667                 rcode = run_list_real(pi);
1668         }
1669         /* free_pipe_list has the side effect of clearing memory
1670          * In the long run that function can be merged with run_list_real,
1671          * but doing that now would hobble the debugging effort. */
1672         free_pipe_list(pi,0);
1673         return rcode;
1674 }
1675
1676 /* The API for glob is arguably broken.  This routine pushes a non-matching
1677  * string into the output structure, removing non-backslashed backslashes.
1678  * If someone can prove me wrong, by performing this function within the
1679  * original glob(3) api, feel free to rewrite this routine into oblivion.
1680  * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1681  * XXX broken if the last character is '\\', check that before calling.
1682  */
1683 static int globhack(const char *src, int flags, glob_t *pglob)
1684 {
1685         int cnt=0, pathc;
1686         const char *s;
1687         char *dest;
1688         for (cnt=1, s=src; s && *s; s++) {
1689                 if (*s == '\\') s++;
1690                 cnt++;
1691         }
1692         dest = malloc(cnt);
1693         if (!dest) return GLOB_NOSPACE;
1694         if (!(flags & GLOB_APPEND)) {
1695                 pglob->gl_pathv=NULL;
1696                 pglob->gl_pathc=0;
1697                 pglob->gl_offs=0;
1698                 pglob->gl_offs=0;
1699         }
1700         pathc = ++pglob->gl_pathc;
1701         pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1702         if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1703         pglob->gl_pathv[pathc-1]=dest;
1704         pglob->gl_pathv[pathc]=NULL;
1705         for (s=src; s && *s; s++, dest++) {
1706                 if (*s == '\\') s++;
1707                 *dest = *s;
1708         }
1709         *dest='\0';
1710         return 0;
1711 }
1712
1713 /* XXX broken if the last character is '\\', check that before calling */
1714 static int glob_needed(const char *s)
1715 {
1716         for (; *s; s++) {
1717                 if (*s == '\\') s++;
1718                 if (strchr("*[?",*s)) return 1;
1719         }
1720         return 0;
1721 }
1722
1723 static int xglob(o_string *dest, int flags, glob_t *pglob)
1724 {
1725         int gr;
1726
1727         /* short-circuit for null word */
1728         /* we can code this better when the debug_printf's are gone */
1729         if (dest->length == 0) {
1730                 if (dest->nonnull) {
1731                         /* bash man page calls this an "explicit" null */
1732                         gr = globhack(dest->data, flags, pglob);
1733                         debug_printf("globhack returned %d\n",gr);
1734                 } else {
1735                         return 0;
1736                 }
1737         } else if (glob_needed(dest->data)) {
1738                 gr = glob(dest->data, flags, NULL, pglob);
1739                 debug_printf("glob returned %d\n",gr);
1740                 if (gr == GLOB_NOMATCH) {
1741                         /* quote removal, or more accurately, backslash removal */
1742                         gr = globhack(dest->data, flags, pglob);
1743                         debug_printf("globhack returned %d\n",gr);
1744                 }
1745         } else {
1746                 gr = globhack(dest->data, flags, pglob);
1747                 debug_printf("globhack returned %d\n",gr);
1748         }
1749         if (gr == GLOB_NOSPACE)
1750                 bb_error_msg_and_die("out of memory during glob");
1751         if (gr != 0) { /* GLOB_ABORTED ? */
1752                 bb_error_msg("glob(3) error %d",gr);
1753         }
1754         /* globprint(glob_target); */
1755         return gr;
1756 }
1757
1758 /* This is used to get/check local shell variables */
1759 static char *get_local_var(const char *s)
1760 {
1761         struct variables *cur;
1762
1763         if (!s)
1764                 return NULL;
1765         for (cur = top_vars; cur; cur=cur->next)
1766                 if(strcmp(cur->name, s)==0)
1767                         return cur->value;
1768         return NULL;
1769 }
1770
1771 /* This is used to set local shell variables
1772    flg_export==0 if only local (not exporting) variable
1773    flg_export==1 if "new" exporting environ
1774    flg_export>1  if current startup environ (not call putenv()) */
1775 static int set_local_var(const char *s, int flg_export)
1776 {
1777         char *name, *value;
1778         int result=0;
1779         struct variables *cur;
1780
1781         name=strdup(s);
1782
1783         /* Assume when we enter this function that we are already in
1784          * NAME=VALUE format.  So the first order of business is to
1785          * split 's' on the '=' into 'name' and 'value' */
1786         value = strchr(name, '=');
1787         if (value==0 && ++value==0) {
1788                 free(name);
1789                 return -1;
1790         }
1791         *value++ = 0;
1792
1793         for(cur = top_vars; cur; cur = cur->next) {
1794                 if(strcmp(cur->name, name)==0)
1795                         break;
1796         }
1797
1798         if(cur) {
1799                 if(strcmp(cur->value, value)==0) {
1800                         if(flg_export>0 && cur->flg_export==0)
1801                                 cur->flg_export=flg_export;
1802                         else
1803                                 result++;
1804                 } else {
1805                         if(cur->flg_read_only) {
1806                                 bb_error_msg("%s: readonly variable", name);
1807                                 result = -1;
1808                         } else {
1809                                 if(flg_export>0 || cur->flg_export>1)
1810                                         cur->flg_export=1;
1811                                 free(cur->value);
1812
1813                                 cur->value = strdup(value);
1814                         }
1815                 }
1816         } else {
1817                 cur = malloc(sizeof(struct variables));
1818                 if(!cur) {
1819                         result = -1;
1820                 } else {
1821                         cur->name = strdup(name);
1822                         if(cur->name == 0) {
1823                                 free(cur);
1824                                 result = -1;
1825                         } else {
1826                                 struct variables *bottom = top_vars;
1827                                 cur->value = strdup(value);
1828                                 cur->next = 0;
1829                                 cur->flg_export = flg_export;
1830                                 cur->flg_read_only = 0;
1831                                 while(bottom->next) bottom=bottom->next;
1832                                 bottom->next = cur;
1833                         }
1834                 }
1835         }
1836
1837         if(result==0 && cur->flg_export==1) {
1838                 *(value-1) = '=';
1839                 result = putenv(name);
1840         } else {
1841                 free(name);
1842                 if(result>0)            /* equivalent to previous set */
1843                         result = 0;
1844         }
1845         return result;
1846 }
1847
1848 static void unset_local_var(const char *name)
1849 {
1850         struct variables *cur;
1851
1852         if (name) {
1853                 for (cur = top_vars; cur; cur=cur->next) {
1854                         if(strcmp(cur->name, name)==0)
1855                                 break;
1856                 }
1857                 if(cur!=0) {
1858                         struct variables *next = top_vars;
1859                         if(cur->flg_read_only) {
1860                                 bb_error_msg("%s: readonly variable", name);
1861                                 return;
1862                         } else {
1863                                 if(cur->flg_export)
1864                                         unsetenv(cur->name);
1865                                 free(cur->name);
1866                                 free(cur->value);
1867                                 while (next->next != cur)
1868                                         next = next->next;
1869                                 next->next = cur->next;
1870                         }
1871                         free(cur);
1872                 }
1873         }
1874 }
1875
1876 static int is_assignment(const char *s)
1877 {
1878         if (s==NULL || !isalpha(*s)) return 0;
1879         ++s;
1880         while(isalnum(*s) || *s=='_') ++s;
1881         return *s=='=';
1882 }
1883
1884 /* the src parameter allows us to peek forward to a possible &n syntax
1885  * for file descriptor duplication, e.g., "2>&1".
1886  * Return code is 0 normally, 1 if a syntax error is detected in src.
1887  * Resource errors (in xmalloc) cause the process to exit */
1888 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1889         struct in_str *input)
1890 {
1891         struct child_prog *child=ctx->child;
1892         struct redir_struct *redir = child->redirects;
1893         struct redir_struct *last_redir=NULL;
1894
1895         /* Create a new redir_struct and drop it onto the end of the linked list */
1896         while(redir) {
1897                 last_redir=redir;
1898                 redir=redir->next;
1899         }
1900         redir = xmalloc(sizeof(struct redir_struct));
1901         redir->next=NULL;
1902         redir->word.gl_pathv=NULL;
1903         if (last_redir) {
1904                 last_redir->next=redir;
1905         } else {
1906                 child->redirects=redir;
1907         }
1908
1909         redir->type=style;
1910         redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1911
1912         debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1913
1914         /* Check for a '2>&1' type redirect */
1915         redir->dup = redirect_dup_num(input);
1916         if (redir->dup == -2) return 1;  /* syntax error */
1917         if (redir->dup != -1) {
1918                 /* Erik had a check here that the file descriptor in question
1919                  * is legit; I postpone that to "run time"
1920                  * A "-" representation of "close me" shows up as a -3 here */
1921                 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
1922         } else {
1923                 /* We do _not_ try to open the file that src points to,
1924                  * since we need to return and let src be expanded first.
1925                  * Set ctx->pending_redirect, so we know what to do at the
1926                  * end of the next parsed word.
1927                  */
1928                 ctx->pending_redirect = redir;
1929         }
1930         return 0;
1931 }
1932
1933 static struct pipe *new_pipe(void) {
1934         struct pipe *pi;
1935         pi = xmalloc(sizeof(struct pipe));
1936         pi->num_progs = 0;
1937         pi->progs = NULL;
1938         pi->next = NULL;
1939         pi->followup = 0;  /* invalid */
1940         pi->r_mode = RES_NONE;
1941         return pi;
1942 }
1943
1944 static void initialize_context(struct p_context *ctx)
1945 {
1946         ctx->pipe=NULL;
1947         ctx->pending_redirect=NULL;
1948         ctx->child=NULL;
1949         ctx->list_head=new_pipe();
1950         ctx->pipe=ctx->list_head;
1951         ctx->w=RES_NONE;
1952         ctx->stack=NULL;
1953         ctx->old_flag=0;
1954         done_command(ctx);   /* creates the memory for working child */
1955 }
1956
1957 /* normal return is 0
1958  * if a reserved word is found, and processed, return 1
1959  * should handle if, then, elif, else, fi, for, while, until, do, done.
1960  * case, function, and select are obnoxious, save those for later.
1961  */
1962 static int reserved_word(o_string *dest, struct p_context *ctx)
1963 {
1964         struct reserved_combo {
1965                 char *literal;
1966                 int code;
1967                 long flag;
1968         };
1969         /* Mostly a list of accepted follow-up reserved words.
1970          * FLAG_END means we are done with the sequence, and are ready
1971          * to turn the compound list into a command.
1972          * FLAG_START means the word must start a new compound list.
1973          */
1974         static struct reserved_combo reserved_list[] = {
1975                 { "if",    RES_IF,    FLAG_THEN | FLAG_START },
1976                 { "then",  RES_THEN,  FLAG_ELIF | FLAG_ELSE | FLAG_FI },
1977                 { "elif",  RES_ELIF,  FLAG_THEN },
1978                 { "else",  RES_ELSE,  FLAG_FI   },
1979                 { "fi",    RES_FI,    FLAG_END  },
1980                 { "for",   RES_FOR,   FLAG_IN   | FLAG_START },
1981                 { "while", RES_WHILE, FLAG_DO   | FLAG_START },
1982                 { "until", RES_UNTIL, FLAG_DO   | FLAG_START },
1983                 { "in",    RES_IN,    FLAG_DO   },
1984                 { "do",    RES_DO,    FLAG_DONE },
1985                 { "done",  RES_DONE,  FLAG_END  }
1986         };
1987         struct reserved_combo *r;
1988         for (r=reserved_list;
1989 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
1990                 r<reserved_list+NRES; r++) {
1991                 if (strcmp(dest->data, r->literal) == 0) {
1992                         debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
1993                         if (r->flag & FLAG_START) {
1994                                 struct p_context *new = xmalloc(sizeof(struct p_context));
1995                                 debug_printf("push stack\n");
1996                                 if (ctx->w == RES_IN || ctx->w == RES_FOR) {
1997                                         syntax();
1998                                         free(new);
1999                                         ctx->w = RES_SNTX;
2000                                         b_reset(dest);
2001                                         return 1;
2002                                 }
2003                                 *new = *ctx;   /* physical copy */
2004                                 initialize_context(ctx);
2005                                 ctx->stack=new;
2006                         } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
2007                                 syntax();
2008                                 ctx->w = RES_SNTX;
2009                                 b_reset(dest);
2010                                 return 1;
2011                         }
2012                         ctx->w=r->code;
2013                         ctx->old_flag = r->flag;
2014                         if (ctx->old_flag & FLAG_END) {
2015                                 struct p_context *old;
2016                                 debug_printf("pop stack\n");
2017                                 done_pipe(ctx,PIPE_SEQ);
2018                                 old = ctx->stack;
2019                                 old->child->group = ctx->list_head;
2020                                 old->child->subshell = 0;
2021                                 *ctx = *old;   /* physical copy */
2022                                 free(old);
2023                         }
2024                         b_reset (dest);
2025                         return 1;
2026                 }
2027         }
2028         return 0;
2029 }
2030
2031 /* normal return is 0.
2032  * Syntax or xglob errors return 1. */
2033 static int done_word(o_string *dest, struct p_context *ctx)
2034 {
2035         struct child_prog *child=ctx->child;
2036         glob_t *glob_target;
2037         int gr, flags = 0;
2038
2039         debug_printf("done_word: %s %p\n", dest->data, child);
2040         if (dest->length == 0 && !dest->nonnull) {
2041                 debug_printf("  true null, ignored\n");
2042                 return 0;
2043         }
2044         if (ctx->pending_redirect) {
2045                 glob_target = &ctx->pending_redirect->word;
2046         } else {
2047                 if (child->group) {
2048                         syntax();
2049                         return 1;  /* syntax error, groups and arglists don't mix */
2050                 }
2051                 if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) {
2052                         debug_printf("checking %s for reserved-ness\n",dest->data);
2053                         if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
2054                 }
2055                 glob_target = &child->glob_result;
2056                 if (child->argv) flags |= GLOB_APPEND;
2057         }
2058         gr = xglob(dest, flags, glob_target);
2059         if (gr != 0) return 1;
2060
2061         b_reset(dest);
2062         if (ctx->pending_redirect) {
2063                 ctx->pending_redirect=NULL;
2064                 if (glob_target->gl_pathc != 1) {
2065                         bb_error_msg("ambiguous redirect");
2066                         return 1;
2067                 }
2068         } else {
2069                 child->argv = glob_target->gl_pathv;
2070         }
2071         if (ctx->w == RES_FOR) {
2072                 done_word(dest,ctx);
2073                 done_pipe(ctx,PIPE_SEQ);
2074         }
2075         return 0;
2076 }
2077
2078 /* The only possible error here is out of memory, in which case
2079  * xmalloc exits. */
2080 static int done_command(struct p_context *ctx)
2081 {
2082         /* The child is really already in the pipe structure, so
2083          * advance the pipe counter and make a new, null child.
2084          * Only real trickiness here is that the uncommitted
2085          * child structure, to which ctx->child points, is not
2086          * counted in pi->num_progs. */
2087         struct pipe *pi=ctx->pipe;
2088         struct child_prog *prog=ctx->child;
2089
2090         if (prog && prog->group == NULL
2091                  && prog->argv == NULL
2092                  && prog->redirects == NULL) {
2093                 debug_printf("done_command: skipping null command\n");
2094                 return 0;
2095         } else if (prog) {
2096                 pi->num_progs++;
2097                 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
2098         } else {
2099                 debug_printf("done_command: initializing\n");
2100         }
2101         pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
2102
2103         prog = pi->progs + pi->num_progs;
2104         prog->redirects = NULL;
2105         prog->argv = NULL;
2106         prog->is_stopped = 0;
2107         prog->group = NULL;
2108         prog->glob_result.gl_pathv = NULL;
2109         prog->family = pi;
2110         prog->sp = 0;
2111         ctx->child = prog;
2112         prog->type = ctx->type;
2113
2114         /* but ctx->pipe and ctx->list_head remain unchanged */
2115         return 0;
2116 }
2117
2118 static int done_pipe(struct p_context *ctx, pipe_style type)
2119 {
2120         struct pipe *new_p;
2121         done_command(ctx);  /* implicit closure of previous command */
2122         debug_printf("done_pipe, type %d\n", type);
2123         ctx->pipe->followup = type;
2124         ctx->pipe->r_mode = ctx->w;
2125         new_p=new_pipe();
2126         ctx->pipe->next = new_p;
2127         ctx->pipe = new_p;
2128         ctx->child = NULL;
2129         done_command(ctx);  /* set up new pipe to accept commands */
2130         return 0;
2131 }
2132
2133 /* peek ahead in the in_str to find out if we have a "&n" construct,
2134  * as in "2>&1", that represents duplicating a file descriptor.
2135  * returns either -2 (syntax error), -1 (no &), or the number found.
2136  */
2137 static int redirect_dup_num(struct in_str *input)
2138 {
2139         int ch, d=0, ok=0;
2140         ch = b_peek(input);
2141         if (ch != '&') return -1;
2142
2143         b_getch(input);  /* get the & */
2144         ch=b_peek(input);
2145         if (ch == '-') {
2146                 b_getch(input);
2147                 return -3;  /* "-" represents "close me" */
2148         }
2149         while (isdigit(ch)) {
2150                 d = d*10+(ch-'0');
2151                 ok=1;
2152                 b_getch(input);
2153                 ch = b_peek(input);
2154         }
2155         if (ok) return d;
2156
2157         bb_error_msg("ambiguous redirect");
2158         return -2;
2159 }
2160
2161 /* If a redirect is immediately preceded by a number, that number is
2162  * supposed to tell which file descriptor to redirect.  This routine
2163  * looks for such preceding numbers.  In an ideal world this routine
2164  * needs to handle all the following classes of redirects...
2165  *     echo 2>foo     # redirects fd  2 to file "foo", nothing passed to echo
2166  *     echo 49>foo    # redirects fd 49 to file "foo", nothing passed to echo
2167  *     echo -2>foo    # redirects fd  1 to file "foo",    "-2" passed to echo
2168  *     echo 49x>foo   # redirects fd  1 to file "foo",   "49x" passed to echo
2169  * A -1 output from this program means no valid number was found, so the
2170  * caller should use the appropriate default for this redirection.
2171  */
2172 static int redirect_opt_num(o_string *o)
2173 {
2174         int num;
2175
2176         if (o->length==0) return -1;
2177         for(num=0; num<o->length; num++) {
2178                 if (!isdigit(*(o->data+num))) {
2179                         return -1;
2180                 }
2181         }
2182         /* reuse num (and save an int) */
2183         num=atoi(o->data);
2184         b_reset(o);
2185         return num;
2186 }
2187
2188 static FILE *generate_stream_from_list(struct pipe *head)
2189 {
2190         FILE *pf;
2191         int pid, channel[2];
2192         if (pipe(channel)<0) bb_perror_msg_and_die("pipe");
2193 #if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
2194         pid=fork();
2195 #else
2196         pid=vfork();
2197 #endif
2198         if (pid<0) {
2199                 bb_perror_msg_and_die("fork");
2200         } else if (pid==0) {
2201                 close(channel[0]);
2202                 if (channel[1] != 1) {
2203                         dup2(channel[1],1);
2204                         close(channel[1]);
2205                 }
2206                 _exit(run_list_real(head));   /* leaks memory */
2207         }
2208         debug_printf("forked child %d\n",pid);
2209         close(channel[1]);
2210         pf = fdopen(channel[0],"r");
2211         debug_printf("pipe on FILE *%p\n",pf);
2212         return pf;
2213 }
2214
2215 /* this version hacked for testing purposes */
2216 /* return code is exit status of the process that is run. */
2217 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2218 {
2219         int retcode;
2220         o_string result=NULL_O_STRING;
2221         struct p_context inner;
2222         FILE *p;
2223         struct in_str pipe_str;
2224         initialize_context(&inner);
2225
2226         /* recursion to generate command */
2227         retcode = parse_stream(&result, &inner, input, subst_end);
2228         if (retcode != 0) return retcode;  /* syntax error or EOF */
2229         done_word(&result, &inner);
2230         done_pipe(&inner, PIPE_SEQ);
2231         b_free(&result);
2232
2233         p=generate_stream_from_list(inner.list_head);
2234         if (p==NULL) return 1;
2235         mark_open(fileno(p));
2236         setup_file_in_str(&pipe_str, p);
2237
2238         /* now send results of command back into original context */
2239         retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2240         /* XXX In case of a syntax error, should we try to kill the child?
2241          * That would be tough to do right, so just read until EOF. */
2242         if (retcode == 1) {
2243                 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
2244         }
2245
2246         debug_printf("done reading from pipe, pclose()ing\n");
2247         /* This is the step that wait()s for the child.  Should be pretty
2248          * safe, since we just read an EOF from its stdout.  We could try
2249          * to better, by using wait(), and keeping track of background jobs
2250          * at the same time.  That would be a lot of work, and contrary
2251          * to the KISS philosophy of this program. */
2252         mark_closed(fileno(p));
2253         retcode=pclose(p);
2254         free_pipe_list(inner.list_head,0);
2255         debug_printf("pclosed, retcode=%d\n",retcode);
2256         /* XXX this process fails to trim a single trailing newline */
2257         return retcode;
2258 }
2259
2260 static int parse_group(o_string *dest, struct p_context *ctx,
2261         struct in_str *input, int ch)
2262 {
2263         int rcode, endch=0;
2264         struct p_context sub;
2265         struct child_prog *child = ctx->child;
2266         if (child->argv) {
2267                 syntax();
2268                 return 1;  /* syntax error, groups and arglists don't mix */
2269         }
2270         initialize_context(&sub);
2271         switch(ch) {
2272                 case '(': endch=')'; child->subshell=1; break;
2273                 case '{': endch='}'; break;
2274                 default: syntax();   /* really logic error */
2275         }
2276         rcode=parse_stream(dest,&sub,input,endch);
2277         done_word(dest,&sub); /* finish off the final word in the subcontext */
2278         done_pipe(&sub, PIPE_SEQ);  /* and the final command there, too */
2279         child->group = sub.list_head;
2280         return rcode;
2281         /* child remains "open", available for possible redirects */
2282 }
2283
2284 /* basically useful version until someone wants to get fancier,
2285  * see the bash man page under "Parameter Expansion" */
2286 static char *lookup_param(char *src)
2287 {
2288         char *p=NULL;
2289         if (src) {
2290                 p = getenv(src);
2291                 if (!p)
2292                         p = get_local_var(src);
2293         }
2294         return p;
2295 }
2296
2297 /* return code: 0 for OK, 1 for syntax error */
2298 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2299 {
2300         int i, advance=0;
2301         char sep[]=" ";
2302         int ch = input->peek(input);  /* first character after the $ */
2303         debug_printf("handle_dollar: ch=%c\n",ch);
2304         if (isalpha(ch)) {
2305                 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2306                 ctx->child->sp++;
2307                 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
2308                         b_getch(input);
2309                         b_addchr(dest,ch);
2310                 }
2311                 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2312         } else if (isdigit(ch)) {
2313                 i = ch-'0';  /* XXX is $0 special? */
2314                 if (i<global_argc) {
2315                         parse_string(dest, ctx, global_argv[i]); /* recursion */
2316                 }
2317                 advance = 1;
2318         } else switch (ch) {
2319                 case '$':
2320                         b_adduint(dest,getpid());
2321                         advance = 1;
2322                         break;
2323                 case '!':
2324                         if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2325                         advance = 1;
2326                         break;
2327                 case '?':
2328                         b_adduint(dest,last_return_code);
2329                         advance = 1;
2330                         break;
2331                 case '#':
2332                         b_adduint(dest,global_argc ? global_argc-1 : 0);
2333                         advance = 1;
2334                         break;
2335                 case '{':
2336                         b_addchr(dest, SPECIAL_VAR_SYMBOL);
2337                         ctx->child->sp++;
2338                         b_getch(input);
2339                         /* XXX maybe someone will try to escape the '}' */
2340                         while(ch=b_getch(input),ch!=EOF && ch!='}') {
2341                                 b_addchr(dest,ch);
2342                         }
2343                         if (ch != '}') {
2344                                 syntax();
2345                                 return 1;
2346                         }
2347                         b_addchr(dest, SPECIAL_VAR_SYMBOL);
2348                         break;
2349                 case '(':
2350                         b_getch(input);
2351                         process_command_subs(dest, ctx, input, ')');
2352                         break;
2353                 case '*':
2354                         sep[0]=ifs[0];
2355                         for (i=1; i<global_argc; i++) {
2356                                 parse_string(dest, ctx, global_argv[i]);
2357                                 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2358                         }
2359                         break;
2360                 case '@':
2361                 case '-':
2362                 case '_':
2363                         /* still unhandled, but should be eventually */
2364                         bb_error_msg("unhandled syntax: $%c",ch);
2365                         return 1;
2366                         break;
2367                 default:
2368                         b_addqchr(dest,'$',dest->quote);
2369         }
2370         /* Eat the character if the flag was set.  If the compiler
2371          * is smart enough, we could substitute "b_getch(input);"
2372          * for all the "advance = 1;" above, and also end up with
2373          * a nice size-optimized program.  Hah!  That'll be the day.
2374          */
2375         if (advance) b_getch(input);
2376         return 0;
2377 }
2378
2379 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2380 {
2381         struct in_str foo;
2382         setup_string_in_str(&foo, src);
2383         return parse_stream(dest, ctx, &foo, '\0');
2384 }
2385
2386 /* return code is 0 for normal exit, 1 for syntax error */
2387 int parse_stream(o_string *dest, struct p_context *ctx,
2388         struct in_str *input, int end_trigger)
2389 {
2390         int ch, m;
2391         int redir_fd;
2392         redir_type redir_style;
2393         int next;
2394
2395         /* Only double-quote state is handled in the state variable dest->quote.
2396          * A single-quote triggers a bypass of the main loop until its mate is
2397          * found.  When recursing, quote state is passed in via dest->quote. */
2398
2399         debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2400         while ((ch=b_getch(input))!=EOF) {
2401                 m = map[ch];
2402                 next = (ch == '\n') ? 0 : b_peek(input);
2403                 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2404                         ch,ch,m,dest->quote);
2405                 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2406                         b_addqchr(dest, ch, dest->quote);
2407                 } else {
2408                         if (m==2) {  /* unquoted IFS */
2409                                 if (done_word(dest, ctx)) {
2410                                         return 1;
2411                                 }
2412                                 /* If we aren't performing a substitution, treat a newline as a
2413                                  * command separator.  */
2414                                 if (end_trigger != '\0' && ch=='\n')
2415                                         done_pipe(ctx,PIPE_SEQ);
2416                         }
2417                         if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2418                                 debug_printf("leaving parse_stream (triggered)\n");
2419                                 return 0;
2420                         }
2421                         if (m!=2) switch (ch) {
2422                 case '#':
2423                         if (dest->length == 0 && !dest->quote) {
2424                                 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2425                         } else {
2426                                 b_addqchr(dest, ch, dest->quote);
2427                         }
2428                         break;
2429                 case '\\':
2430                         if (next == EOF) {
2431                                 syntax();
2432                                 return 1;
2433                         }
2434                         b_addqchr(dest, '\\', dest->quote);
2435                         b_addqchr(dest, b_getch(input), dest->quote);
2436                         break;
2437                 case '$':
2438                         if (handle_dollar(dest, ctx, input)!=0) return 1;
2439                         break;
2440                 case '\'':
2441                         dest->nonnull = 1;
2442                         while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2443                                 b_addchr(dest,ch);
2444                         }
2445                         if (ch==EOF) {
2446                                 syntax();
2447                                 return 1;
2448                         }
2449                         break;
2450                 case '"':
2451                         dest->nonnull = 1;
2452                         dest->quote = !dest->quote;
2453                         break;
2454                 case '`':
2455                         process_command_subs(dest, ctx, input, '`');
2456                         break;
2457                 case '>':
2458                         redir_fd = redirect_opt_num(dest);
2459                         done_word(dest, ctx);
2460                         redir_style=REDIRECT_OVERWRITE;
2461                         if (next == '>') {
2462                                 redir_style=REDIRECT_APPEND;
2463                                 b_getch(input);
2464                         } else if (next == '(') {
2465                                 syntax();   /* until we support >(list) Process Substitution */
2466                                 return 1;
2467                         }
2468                         setup_redirect(ctx, redir_fd, redir_style, input);
2469                         break;
2470                 case '<':
2471                         redir_fd = redirect_opt_num(dest);
2472                         done_word(dest, ctx);
2473                         redir_style=REDIRECT_INPUT;
2474                         if (next == '<') {
2475                                 redir_style=REDIRECT_HEREIS;
2476                                 b_getch(input);
2477                         } else if (next == '>') {
2478                                 redir_style=REDIRECT_IO;
2479                                 b_getch(input);
2480                         } else if (next == '(') {
2481                                 syntax();   /* until we support <(list) Process Substitution */
2482                                 return 1;
2483                         }
2484                         setup_redirect(ctx, redir_fd, redir_style, input);
2485                         break;
2486                 case ';':
2487                         done_word(dest, ctx);
2488                         done_pipe(ctx,PIPE_SEQ);
2489                         break;
2490                 case '&':
2491                         done_word(dest, ctx);
2492                         if (next=='&') {
2493                                 b_getch(input);
2494                                 done_pipe(ctx,PIPE_AND);
2495                         } else {
2496                                 done_pipe(ctx,PIPE_BG);
2497                         }
2498                         break;
2499                 case '|':
2500                         done_word(dest, ctx);
2501                         if (next=='|') {
2502                                 b_getch(input);
2503                                 done_pipe(ctx,PIPE_OR);
2504                         } else {
2505                                 /* we could pick up a file descriptor choice here
2506                                  * with redirect_opt_num(), but bash doesn't do it.
2507                                  * "echo foo 2| cat" yields "foo 2". */
2508                                 done_command(ctx);
2509                         }
2510                         break;
2511                 case '(':
2512                 case '{':
2513                         if (parse_group(dest, ctx, input, ch)!=0) return 1;
2514                         break;
2515                 case ')':
2516                 case '}':
2517                         syntax();   /* Proper use of this character caught by end_trigger */
2518                         return 1;
2519                         break;
2520                 default:
2521                         syntax();   /* this is really an internal logic error */
2522                         return 1;
2523                         }
2524                 }
2525         }
2526         /* complain if quote?  No, maybe we just finished a command substitution
2527          * that was quoted.  Example:
2528          * $ echo "`cat foo` plus more"
2529          * and we just got the EOF generated by the subshell that ran "cat foo"
2530          * The only real complaint is if we got an EOF when end_trigger != '\0',
2531          * that is, we were really supposed to get end_trigger, and never got
2532          * one before the EOF.  Can't use the standard "syntax error" return code,
2533          * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2534         debug_printf("leaving parse_stream (EOF)\n");
2535         if (end_trigger != '\0') return -1;
2536         return 0;
2537 }
2538
2539 static void mapset(const char *set, int code)
2540 {
2541         const unsigned char *s;
2542         for (s = (const unsigned char *)set; *s; s++) map[(int)*s] = code;
2543 }
2544
2545 static void update_ifs_map(void)
2546 {
2547         /* char *ifs and char map[256] are both globals. */
2548         ifs = getenv("IFS");
2549         if (ifs == NULL) ifs=" \t\n";
2550         /* Precompute a list of 'flow through' behavior so it can be treated
2551          * quickly up front.  Computation is necessary because of IFS.
2552          * Special case handling of IFS == " \t\n" is not implemented.
2553          * The map[] array only really needs two bits each, and on most machines
2554          * that would be faster because of the reduced L1 cache footprint.
2555          */
2556         memset(map,0,sizeof(map)); /* most characters flow through always */
2557         mapset("\\$'\"`", 3);      /* never flow through */
2558         mapset("<>;&|(){}#", 1);   /* flow through if quoted */
2559         mapset(ifs, 2);            /* also flow through if quoted */
2560 }
2561
2562 /* most recursion does not come through here, the exception is
2563  * from builtin_source() */
2564 int parse_stream_outer(struct in_str *inp, int flag)
2565 {
2566
2567         struct p_context ctx;
2568         o_string temp=NULL_O_STRING;
2569         int rcode;
2570         do {
2571                 ctx.type = flag;
2572                 initialize_context(&ctx);
2573                 update_ifs_map();
2574                 if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING)) mapset(";$&|", 0);
2575                 inp->promptmode=1;
2576                 rcode = parse_stream(&temp, &ctx, inp, '\n');
2577                 if (rcode != 1 && ctx.old_flag != 0) {
2578                         syntax();
2579                 }
2580                 if (rcode != 1 && ctx.old_flag == 0) {
2581                         done_word(&temp, &ctx);
2582                         done_pipe(&ctx,PIPE_SEQ);
2583                         run_list(ctx.list_head);
2584                 } else {
2585                         if (ctx.old_flag != 0) {
2586                                 free(ctx.stack);
2587                                 b_reset(&temp);
2588                         }
2589                         temp.nonnull = 0;
2590                         temp.quote = 0;
2591                         inp->p = NULL;
2592                         free_pipe_list(ctx.list_head,0);
2593                 }
2594                 b_free(&temp);
2595         } while (rcode != -1 && !(flag & FLAG_EXIT_FROM_LOOP));   /* loop on syntax errors, return on EOF */
2596         return 0;
2597 }
2598
2599 static int parse_string_outer(const char *s, int flag)
2600 {
2601         struct in_str input;
2602         setup_string_in_str(&input, s);
2603         return parse_stream_outer(&input, flag);
2604 }
2605
2606 static int parse_file_outer(FILE *f)
2607 {
2608         int rcode;
2609         struct in_str input;
2610         setup_file_in_str(&input, f);
2611         rcode = parse_stream_outer(&input, FLAG_PARSE_SEMICOLON);
2612         return rcode;
2613 }
2614
2615 /* Make sure we have a controlling tty.  If we get started under a job
2616  * aware app (like bash for example), make sure we are now in charge so
2617  * we don't fight over who gets the foreground */
2618 static void setup_job_control(void)
2619 {
2620         static pid_t shell_pgrp;
2621         /* Loop until we are in the foreground.  */
2622         while (tcgetpgrp (shell_terminal) != (shell_pgrp = getpgrp ()))
2623                 kill (- shell_pgrp, SIGTTIN);
2624
2625         /* Ignore interactive and job-control signals.  */
2626         signal(SIGINT, SIG_IGN);
2627         signal(SIGQUIT, SIG_IGN);
2628         signal(SIGTERM, SIG_IGN);
2629         signal(SIGTSTP, SIG_IGN);
2630         signal(SIGTTIN, SIG_IGN);
2631         signal(SIGTTOU, SIG_IGN);
2632         signal(SIGCHLD, SIG_IGN);
2633
2634         /* Put ourselves in our own process group.  */
2635         setsid();
2636         shell_pgrp = getpid ();
2637         setpgid (shell_pgrp, shell_pgrp);
2638
2639         /* Grab control of the terminal.  */
2640         tcsetpgrp(shell_terminal, shell_pgrp);
2641 }
2642
2643 int hush_main(int argc, char **argv)
2644 {
2645         int opt;
2646         FILE *input;
2647         char **e = environ;
2648
2649         /* XXX what should these be while sourcing /etc/profile? */
2650         global_argc = argc;
2651         global_argv = argv;
2652
2653         /* (re?) initialize globals.  Sometimes hush_main() ends up calling
2654          * hush_main(), therefore we cannot rely on the BSS to zero out this
2655          * stuff.  Reset these to 0 every time. */
2656         ifs = NULL;
2657         /* map[] is taken care of with call to update_ifs_map() */
2658         fake_mode = 0;
2659         interactive = 0;
2660         close_me_head = NULL;
2661         last_bg_pid = 0;
2662         job_list = NULL;
2663         last_jobid = 0;
2664
2665         /* Initialize some more globals to non-zero values */
2666         set_cwd();
2667 #ifdef CONFIG_FEATURE_COMMAND_EDITING
2668         cmdedit_set_initial_prompt();
2669 #else
2670         PS1 = NULL;
2671 #endif
2672         PS2 = "> ";
2673
2674         /* initialize our shell local variables with the values
2675          * currently living in the environment */
2676         if (e) {
2677                 for (; *e; e++)
2678                         set_local_var(*e, 2);   /* without call putenv() */
2679         }
2680
2681         last_return_code=EXIT_SUCCESS;
2682
2683
2684         if (argv[0] && argv[0][0] == '-') {
2685                 debug_printf("\nsourcing /etc/profile\n");
2686                 if ((input = fopen("/etc/profile", "r")) != NULL) {
2687                         mark_open(fileno(input));
2688                         parse_file_outer(input);
2689                         mark_closed(fileno(input));
2690                         fclose(input);
2691                 }
2692         }
2693         input=stdin;
2694
2695         while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2696                 switch (opt) {
2697                         case 'c':
2698                                 {
2699                                         global_argv = argv+optind;
2700                                         global_argc = argc-optind;
2701                                         opt = parse_string_outer(optarg, FLAG_PARSE_SEMICOLON);
2702                                         goto final_return;
2703                                 }
2704                                 break;
2705                         case 'i':
2706                                 interactive++;
2707                                 break;
2708                         case 'f':
2709                                 fake_mode++;
2710                                 break;
2711                         default:
2712 #ifndef BB_VER
2713                                 fprintf(stderr, "Usage: sh [FILE]...\n"
2714                                                 "   or: sh -c command [args]...\n\n");
2715                                 exit(EXIT_FAILURE);
2716 #else
2717                                 bb_show_usage();
2718 #endif
2719                 }
2720         }
2721         /* A shell is interactive if the `-i' flag was given, or if all of
2722          * the following conditions are met:
2723          *        no -c command
2724          *    no arguments remaining or the -s flag given
2725          *    standard input is a terminal
2726          *    standard output is a terminal
2727          *    Refer to Posix.2, the description of the `sh' utility. */
2728         if (argv[optind]==NULL && input==stdin &&
2729                         isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
2730                 interactive++;
2731         }
2732
2733         debug_printf("\ninteractive=%d\n", interactive);
2734         if (interactive) {
2735                 /* Looks like they want an interactive shell */
2736 #ifndef CONFIG_FEATURE_SH_EXTRA_QUIET
2737                 printf( "\n\n%s hush - the humble shell v0.01 (testing)\n",
2738                         BB_BANNER);
2739                 printf( "Enter 'help' for a list of built-in commands.\n\n");
2740 #endif
2741                 setup_job_control();
2742         }
2743
2744         if (argv[optind]==NULL) {
2745                 opt=parse_file_outer(stdin);
2746                 goto final_return;
2747         }
2748
2749         debug_printf("\nrunning script '%s'\n", argv[optind]);
2750         global_argv = argv+optind;
2751         global_argc = argc-optind;
2752         input = xfopen(argv[optind], "r");
2753         opt = parse_file_outer(input);
2754
2755 #ifdef CONFIG_FEATURE_CLEAN_UP
2756         fclose(input);
2757         if (cwd && cwd != bb_msg_unknown)
2758                 free((char*)cwd);
2759         {
2760                 struct variables *cur, *tmp;
2761                 for(cur = top_vars; cur; cur = tmp) {
2762                         tmp = cur->next;
2763                         if (!cur->flg_read_only) {
2764                                 free(cur->name);
2765                                 free(cur->value);
2766                                 free(cur);
2767                         }
2768                 }
2769         }
2770 #endif
2771
2772 final_return:
2773         return(opt?opt:last_return_code);
2774 }
2775
2776 static char *insert_var_value(char *inp)
2777 {
2778         int res_str_len = 0;
2779         int len;
2780         int done = 0;
2781         char *p, *p1, *res_str = NULL;
2782
2783         while ((p = strchr(inp, SPECIAL_VAR_SYMBOL))) {
2784                 if (p != inp) {
2785                         len = p - inp;
2786                         res_str = xrealloc(res_str, (res_str_len + len));
2787                         strncpy((res_str + res_str_len), inp, len);
2788                         res_str_len += len;
2789                 }
2790                 inp = ++p;
2791                 p = strchr(inp, SPECIAL_VAR_SYMBOL);
2792                 *p = '\0';
2793                 if ((p1 = lookup_param(inp))) {
2794                         len = res_str_len + strlen(p1);
2795                         res_str = xrealloc(res_str, (1 + len));
2796                         strcpy((res_str + res_str_len), p1);
2797                         res_str_len = len;
2798                 }
2799                 *p = SPECIAL_VAR_SYMBOL;
2800                 inp = ++p;
2801                 done = 1;
2802         }
2803         if (done) {
2804                 res_str = xrealloc(res_str, (1 + res_str_len + strlen(inp)));
2805                 strcpy((res_str + res_str_len), inp);
2806                 while ((p = strchr(res_str, '\n'))) {
2807                         *p = ' ';
2808                 }
2809         }
2810         return (res_str == NULL) ? inp : res_str;
2811 }
2812
2813 static char **make_list_in(char **inp, char *name)
2814 {
2815         int len, i;
2816         int name_len = strlen(name);
2817         int n = 0;
2818         char **list;
2819         char *p1, *p2, *p3;
2820
2821         /* create list of variable values */
2822         list = xmalloc(sizeof(*list));
2823         for (i = 0; inp[i]; i++) {
2824                 p3 = insert_var_value(inp[i]);
2825                 p1 = p3;
2826                 while (*p1) {
2827                         if ((*p1 == ' ')) {
2828                                 p1++;
2829                                 continue;
2830                         }
2831                         if ((p2 = strchr(p1, ' '))) {
2832                                 len = p2 - p1;
2833                         } else {
2834                                 len = strlen(p1);
2835                                 p2 = p1 + len;
2836                         }
2837                         /* we use n + 2 in realloc for list,because we add
2838                          * new element and then we will add NULL element */
2839                         list = xrealloc(list, sizeof(*list) * (n + 2));
2840                         list[n] = xmalloc(2 + name_len + len);
2841                         strcpy(list[n], name);
2842                         strcat(list[n], "=");
2843                         strncat(list[n], p1, len);
2844                         list[n++][name_len + len + 1] = '\0';
2845                         p1 = p2;
2846                 }
2847                 if (p3 != inp[i]) free(p3);
2848         }
2849         list[n] = NULL;
2850         return list;
2851 }
2852
2853 /* Make new string for parser */
2854 static char * make_string(char ** inp)
2855 {
2856         char *p;
2857         char *str = NULL;
2858         int n;
2859         int len = 2;
2860
2861         for (n = 0; inp[n]; n++) {
2862                 p = insert_var_value(inp[n]);
2863                 str = xrealloc(str, (len + strlen(p)));
2864                 if (n) {
2865                         strcat(str, " ");
2866                 } else {
2867                         *str = '\0';
2868                 }
2869                 strcat(str, p);
2870                 len = strlen(str) + 3;
2871                 if (p != inp[n]) free(p);
2872         }
2873         len = strlen(str);
2874         *(str + len) = '\n';
2875         *(str + len + 1) = '\0';
2876         return str;
2877 }