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 inline 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 #else
 302 static inline void debug_printf(const char *format ATTRIBUTE_UNUSED, ...) { }
 303 #endif
 304 #define final_printf debug_printf
 305
 306 static void __syntax(char *file, int line) {
 307         bb_error_msg("syntax error %s:%d", file, line);
 308 }
 309 #define syntax() __syntax(__FILE__, __LINE__)
 310
 311 /* Index of subroutines: */
 312 /*   function prototypes for builtins */
 313 static int builtin_cd(struct child_prog *child);
 314 static int builtin_env(struct child_prog *child);
 315 static int builtin_eval(struct child_prog *child);
 316 static int builtin_exec(struct child_prog *child);
 317 static int builtin_exit(struct child_prog *child);
 318 static int builtin_export(struct child_prog *child);
 319 static int builtin_fg_bg(struct child_prog *child);
 320 static int builtin_help(struct child_prog *child);
 321 static int builtin_jobs(struct child_prog *child);
 322 static int builtin_pwd(struct child_prog *child);
 323 static int builtin_read(struct child_prog *child);
 324 static int builtin_set(struct child_prog *child);
 325 static int builtin_shift(struct child_prog *child);
 326 static int builtin_source(struct child_prog *child);
 327 static int builtin_umask(struct child_prog *child);
 328 static int builtin_unset(struct child_prog *child);
 329 static int builtin_not_written(struct child_prog *child);
 330 /*   o_string manipulation: */
 331 static int b_check_space(o_string *o, int len);
 332 static int b_addchr(o_string *o, int ch);
 333 static void b_reset(o_string *o);
 334 static int b_addqchr(o_string *o, int ch, int quote);
 335 static int b_adduint(o_string *o, unsigned int i);
 336 /*  in_str manipulations: */
 337 static int static_get(struct in_str *i);
 338 static int static_peek(struct in_str *i);
 339 static int file_get(struct in_str *i);
 340 static int file_peek(struct in_str *i);
 341 static void setup_file_in_str(struct in_str *i, FILE *f);
 342 static void setup_string_in_str(struct in_str *i, const char *s);
 343 /*  close_me manipulations: */
 344 static void mark_open(int fd);
 345 static void mark_closed(int fd);
 346 static void close_all(void);
 347 /*  "run" the final data structures: */
 348 static char *indenter(int i);
 349 static int free_pipe_list(struct pipe *head, int indent);
 350 static int free_pipe(struct pipe *pi, int indent);
 351 /*  really run the final data structures: */
 352 static int setup_redirects(struct child_prog *prog, int squirrel[]);
 353 static int run_list_real(struct pipe *pi);
 354 static void pseudo_exec(struct child_prog *child) ATTRIBUTE_NORETURN;
 355 static int run_pipe_real(struct pipe *pi);
 356 /*   extended glob support: */
 357 static int globhack(const char *src, int flags, glob_t *pglob);
 358 static int glob_needed(const char *s);
 359 static int xglob(o_string *dest, int flags, glob_t *pglob);
 360 /*   variable assignment: */
 361 static int is_assignment(const char *s);
 362 /*   data structure manipulation: */
 363 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
 364 static void initialize_context(struct p_context *ctx);
 365 static int done_word(o_string *dest, struct p_context *ctx);
 366 static int done_command(struct p_context *ctx);
 367 static int done_pipe(struct p_context *ctx, pipe_style type);
 368 /*   primary string parsing: */
 369 static int redirect_dup_num(struct in_str *input);
 370 static int redirect_opt_num(o_string *o);
 371 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
 372 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
 373 static char *lookup_param(char *src);
 374 static char *make_string(char **inp);
 375 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
 376 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
 377 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
 378 /*   setup: */
 379 static int parse_stream_outer(struct in_str *inp, int flag);
 380 static int parse_string_outer(const char *s, int flag);
 381 static int parse_file_outer(FILE *f);
 382 /*   job management: */
 383 static int checkjobs(struct pipe* fg_pipe);
 384 static void insert_bg_job(struct pipe *pi);
 385 static void remove_bg_job(struct pipe *pi);
 386 /*     local variable support */
 387 static char **make_list_in(char **inp, char *name);
 388 static char *insert_var_value(char *inp);
 389 static char *get_local_var(const char *var);
 390 static void  unset_local_var(const char *name);
 391 static int set_local_var(const char *s, int flg_export);
 392
 393 /* Table of built-in functions.  They can be forked or not, depending on
 394  * context: within pipes, they fork.  As simple commands, they do not.
 395  * When used in non-forking context, they can change global variables
 396  * in the parent shell process.  If forked, of course they can not.
 397  * For example, 'unset foo | whatever' will parse and run, but foo will
 398  * still be set at the end. */
 399 static const struct built_in_command bltins[] = {
 400         {"bg", "Resume a job in the background", builtin_fg_bg},
 401         {"break", "Exit for, while or until loop", builtin_not_written},
 402         {"cd", "Change working directory", builtin_cd},
 403         {"continue", "Continue for, while or until loop", builtin_not_written},
 404         {"env", "Print all environment variables", builtin_env},
 405         {"eval", "Construct and run shell command", builtin_eval},
 406         {"exec", "Exec command, replacing this shell with the exec'd process",
 407                 builtin_exec},
 408         {"exit", "Exit from shell()", builtin_exit},
 409         {"export", "Set environment variable", builtin_export},
 410         {"fg", "Bring job into the foreground", builtin_fg_bg},
 411         {"jobs", "Lists the active jobs", builtin_jobs},
 412         {"pwd", "Print current directory", builtin_pwd},
 413         {"read", "Input environment variable", builtin_read},
 414         {"return", "Return from a function", builtin_not_written},
 415         {"set", "Set/unset shell local variables", builtin_set},
 416         {"shift", "Shift positional parameters", builtin_shift},
 417         {"trap", "Trap signals", builtin_not_written},
 418         {"ulimit","Controls resource limits", builtin_not_written},
 419         {"umask","Sets file creation mask", builtin_umask},
 420         {"unset", "Unset environment variable", builtin_unset},
 421         {".", "Source-in and run commands in a file", builtin_source},
 422         {"help", "List shell built-in commands", builtin_help},
 423         {NULL, NULL, NULL}
 424 };
 425
 426 static const char *set_cwd(void)
 427 {
 428         if(cwd==bb_msg_unknown)
 429                 cwd = NULL;     /* xgetcwd(arg) called free(arg) */
 430         cwd = xgetcwd((char *)cwd);
 431         if (!cwd)
 432                 cwd = bb_msg_unknown;
 433         return cwd;
 434 }
 435
 436 /* built-in 'eval' handler */
 437 static int builtin_eval(struct child_prog *child)
 438 {
 439         char *str = NULL;
 440         int rcode = EXIT_SUCCESS;
 441
 442         if (child->argv[1]) {
 443                 str = make_string(child->argv + 1);
 444                 parse_string_outer(str, FLAG_EXIT_FROM_LOOP |
 445                                         FLAG_PARSE_SEMICOLON);
 446                 free(str);
 447                 rcode = last_return_code;
 448         }
 449         return rcode;
 450 }
 451
 452 /* built-in 'cd <path>' handler */
 453 static int builtin_cd(struct child_prog *child)
 454 {
 455         char *newdir;
 456         if (child->argv[1] == NULL)
 457                 newdir = getenv("HOME");
 458         else
 459                 newdir = child->argv[1];
 460         if (chdir(newdir)) {
 461                 printf("cd: %s: %s\n", newdir, strerror(errno));
 462                 return EXIT_FAILURE;
 463         }
 464         set_cwd();
 465         return EXIT_SUCCESS;
 466 }
 467
 468 /* built-in 'env' handler */
 469 static int builtin_env(struct child_prog *dummy ATTRIBUTE_UNUSED)
 470 {
 471         char **e = environ;
 472         if (e == NULL) return EXIT_FAILURE;
 473         for (; *e; e++) {
 474                 puts(*e);
 475         }
 476         return EXIT_SUCCESS;
 477 }
 478
 479 /* built-in 'exec' handler */
 480 static int builtin_exec(struct child_prog *child)
 481 {
 482         if (child->argv[1] == NULL)
 483                 return EXIT_SUCCESS;   /* Really? */
 484         child->argv++;
 485         pseudo_exec(child);
 486         /* never returns */
 487 }
 488
 489 /* built-in 'exit' handler */
 490 static int builtin_exit(struct child_prog *child)
 491 {
 492         if (child->argv[1] == NULL)
 493                 exit(last_return_code);
 494         exit (atoi(child->argv[1]));
 495 }
 496
 497 /* built-in 'export VAR=value' handler */
 498 static int builtin_export(struct child_prog *child)
 499 {
 500         int res = 0;
 501         char *name = child->argv[1];
 502
 503         if (name == NULL) {
 504                 return (builtin_env(child));
 505         }
 506
 507         name = strdup(name);
 508
 509         if(name) {
 510                 char *value = strchr(name, '=');
 511
 512                 if (!value) {
 513                         char *tmp;
 514                         /* They are exporting something without an =VALUE */
 515
 516                         value = get_local_var(name);
 517                         if (value) {
 518                                 size_t ln = strlen(name);
 519
 520                                 tmp = realloc(name, ln+strlen(value)+2);
 521                                 if(tmp==NULL)
 522                                         res = -1;
 523                                 else {
 524                                         sprintf(tmp+ln, "=%s", value);
 525                                         name = tmp;
 526                                 }
 527                         } else {
 528                                 /* bash does not return an error when trying to export
 529                                  * an undefined variable.  Do likewise. */
 530                                 res = 1;
 531                         }
 532                 }
 533         }
 534         if (res<0)
 535                 bb_perror_msg("export");
 536         else if(res==0)
 537                 res = set_local_var(name, 1);
 538         else
 539                 res = 0;
 540         free(name);
 541         return res;
 542 }
 543
 544 /* built-in 'fg' and 'bg' handler */
 545 static int builtin_fg_bg(struct child_prog *child)
 546 {
 547         int i, jobnum;
 548         struct pipe *pi=NULL;
 549
 550         if (!interactive)
 551                 return EXIT_FAILURE;
 552         /* If they gave us no args, assume they want the last backgrounded task */
 553         if (!child->argv[1]) {
 554                 for (pi = job_list; pi; pi = pi->next) {
 555                         if (pi->jobid == last_jobid) {
 556                                 break;
 557                         }
 558                 }
 559                 if (!pi) {
 560                         bb_error_msg("%s: no current job", child->argv[0]);
 561                         return EXIT_FAILURE;
 562                 }
 563         } else {
 564                 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
 565                         bb_error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
 566                         return EXIT_FAILURE;
 567                 }
 568                 for (pi = job_list; pi; pi = pi->next) {
 569                         if (pi->jobid == jobnum) {
 570                                 break;
 571                         }
 572                 }
 573                 if (!pi) {
 574                         bb_error_msg("%s: %d: no such job", child->argv[0], jobnum);
 575                         return EXIT_FAILURE;
 576                 }
 577         }
 578
 579         if (*child->argv[0] == 'f') {
 580                 /* Put the job into the foreground.  */
 581                 tcsetpgrp(shell_terminal, pi->pgrp);
 582         }
 583
 584         /* Restart the processes in the job */
 585         for (i = 0; i < pi->num_progs; i++)
 586                 pi->progs[i].is_stopped = 0;
 587
 588         if ( (i=kill(- pi->pgrp, SIGCONT)) < 0) {
 589                 if (i == ESRCH) {
 590                         remove_bg_job(pi);
 591                 } else {
 592                         bb_perror_msg("kill (SIGCONT)");
 593                 }
 594         }
 595
 596         pi->stopped_progs = 0;
 597         return EXIT_SUCCESS;
 598 }
 599
 600 /* built-in 'help' handler */
 601 static int builtin_help(struct child_prog *dummy ATTRIBUTE_UNUSED)
 602 {
 603         const struct built_in_command *x;
 604
 605         printf("\nBuilt-in commands:\n");
 606         printf("-------------------\n");
 607         for (x = bltins; x->cmd; x++) {
 608                 if (x->descr==NULL)
 609                         continue;
 610                 printf("%s\t%s\n", x->cmd, x->descr);
 611         }
 612         printf("\n\n");
 613         return EXIT_SUCCESS;
 614 }
 615
 616 /* built-in 'jobs' handler */
 617 static int builtin_jobs(struct child_prog *child ATTRIBUTE_UNUSED)
 618 {
 619         struct pipe *job;
 620         char *status_string;
 621
 622         for (job = job_list; job; job = job->next) {
 623                 if (job->running_progs == job->stopped_progs)
 624                         status_string = "Stopped";
 625                 else
 626                         status_string = "Running";
 627
 628                 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
 629         }
 630         return EXIT_SUCCESS;
 631 }
 632
 633
 634 /* built-in 'pwd' handler */
 635 static int builtin_pwd(struct child_prog *dummy ATTRIBUTE_UNUSED)
 636 {
 637         puts(set_cwd());
 638         return EXIT_SUCCESS;
 639 }
 640
 641 /* built-in 'read VAR' handler */
 642 static int builtin_read(struct child_prog *child)
 643 {
 644         int res;
 645
 646         if (child->argv[1]) {
 647                 char string[BUFSIZ];
 648                 char *var = 0;
 649
 650                 string[0] = 0;  /* In case stdin has only EOF */
 651                 /* read string */
 652                 fgets(string, sizeof(string), stdin);
 653                 chomp(string);
 654                 var = malloc(strlen(child->argv[1])+strlen(string)+2);
 655                 if(var) {
 656                         sprintf(var, "%s=%s", child->argv[1], string);
 657                         res = set_local_var(var, 0);
 658                 } else
 659                         res = -1;
 660                 if (res)
 661                         bb_perror_msg("read");
 662                 free(var);      /* So not move up to avoid breaking errno */
 663                 return res;
 664         } else {
 665                 do res=getchar(); while(res!='\n' && res!=EOF);
 666                 return 0;
 667         }
 668 }
 669
 670 /* built-in 'set VAR=value' handler */
 671 static int builtin_set(struct child_prog *child)
 672 {
 673         char *temp = child->argv[1];
 674         struct variables *e;
 675
 676         if (temp == NULL)
 677                 for(e = top_vars; e; e=e->next)
 678                         printf("%s=%s\n", e->name, e->value);
 679         else
 680                 set_local_var(temp, 0);
 681
 682                 return EXIT_SUCCESS;
 683 }
 684
 685
 686 /* Built-in 'shift' handler */
 687 static int builtin_shift(struct child_prog *child)
 688 {
 689         int n=1;
 690         if (child->argv[1]) {
 691                 n=atoi(child->argv[1]);
 692         }
 693         if (n>=0 && n<global_argc) {
 694                 /* XXX This probably breaks $0 */
 695                 global_argc -= n;
 696                 global_argv += n;
 697                 return EXIT_SUCCESS;
 698         } else {
 699                 return EXIT_FAILURE;
 700         }
 701 }
 702
 703 /* Built-in '.' handler (read-in and execute commands from file) */
 704 static int builtin_source(struct child_prog *child)
 705 {
 706         FILE *input;
 707         int status;
 708
 709         if (child->argv[1] == NULL)
 710                 return EXIT_FAILURE;
 711
 712         /* XXX search through $PATH is missing */
 713         input = fopen(child->argv[1], "r");
 714         if (!input) {
 715                 bb_error_msg("Couldn't open file '%s'", child->argv[1]);
 716                 return EXIT_FAILURE;
 717         }
 718
 719         /* Now run the file */
 720         /* XXX argv and argc are broken; need to save old global_argv
 721          * (pointer only is OK!) on this stack frame,
 722          * set global_argv=child->argv+1, recurse, and restore. */
 723         mark_open(fileno(input));
 724         status = parse_file_outer(input);
 725         mark_closed(fileno(input));
 726         fclose(input);
 727         return (status);
 728 }
 729
 730 static int builtin_umask(struct child_prog *child)
 731 {
 732         mode_t new_umask;
 733         const char *arg = child->argv[1];
 734         char *end;
 735         if (arg) {
 736                 new_umask=strtoul(arg, &end, 8);
 737                 if (*end!='\0' || end == arg) {
 738                         return EXIT_FAILURE;
 739                 }
 740         } else {
 741                 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
 742         }
 743         umask(new_umask);
 744         return EXIT_SUCCESS;
 745 }
 746
 747 /* built-in 'unset VAR' handler */
 748 static int builtin_unset(struct child_prog *child)
 749 {
 750         /* bash returned already true */
 751         unset_local_var(child->argv[1]);
 752         return EXIT_SUCCESS;
 753 }
 754
 755 static int builtin_not_written(struct child_prog *child)
 756 {
 757         printf("builtin_%s not written\n",child->argv[0]);
 758         return EXIT_FAILURE;
 759 }
 760
 761 static int b_check_space(o_string *o, int len)
 762 {
 763         /* It would be easy to drop a more restrictive policy
 764          * in here, such as setting a maximum string length */
 765         if (o->length + len > o->maxlen) {
 766                 char *old_data = o->data;
 767                 /* assert (data == NULL || o->maxlen != 0); */
 768                 o->maxlen += max(2*len, B_CHUNK);
 769                 o->data = realloc(o->data, 1 + o->maxlen);
 770                 if (o->data == NULL) {
 771                         free(old_data);
 772                 }
 773         }
 774         return o->data == NULL;
 775 }
 776
 777 static int b_addchr(o_string *o, int ch)
 778 {
 779         debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
 780         if (b_check_space(o, 1)) return B_NOSPAC;
 781         o->data[o->length] = ch;
 782         o->length++;
 783         o->data[o->length] = '\0';
 784         return 0;
 785 }
 786
 787 static void b_reset(o_string *o)
 788 {
 789         o->length = 0;
 790         o->nonnull = 0;
 791         if (o->data != NULL) *o->data = '\0';
 792 }
 793
 794 static void b_free(o_string *o)
 795 {
 796         b_reset(o);
 797         free(o->data);
 798         o->data = NULL;
 799         o->maxlen = 0;
 800 }
 801
 802 /* My analysis of quoting semantics tells me that state information
 803  * is associated with a destination, not a source.
 804  */
 805 static int b_addqchr(o_string *o, int ch, int quote)
 806 {
 807         if (quote && strchr("*?[\\",ch)) {
 808                 int rc;
 809                 rc = b_addchr(o, '\\');
 810                 if (rc) return rc;
 811         }
 812         return b_addchr(o, ch);
 813 }
 814
 815 /* belongs in utility.c */
 816 static char *simple_itoa(unsigned int i)
 817 {
 818         /* 21 digits plus null terminator, good for 64-bit or smaller ints */
 819         static char local[22];
 820         char *p = &local[21];
 821         *p-- = '\0';
 822         do {
 823                 *p-- = '0' + i % 10;
 824                 i /= 10;
 825         } while (i > 0);
 826         return p + 1;
 827 }
 828
 829 static int b_adduint(o_string *o, unsigned int i)
 830 {
 831         int r;
 832         char *p = simple_itoa(i);
 833         /* no escape checking necessary */
 834         do r=b_addchr(o, *p++); while (r==0 && *p);
 835         return r;
 836 }
 837
 838 static int static_get(struct in_str *i)
 839 {
 840         int ch=*i->p++;
 841         if (ch=='\0') return EOF;
 842         return ch;
 843 }
 844
 845 static int static_peek(struct in_str *i)
 846 {
 847         return *i->p;
 848 }
 849
 850 static inline void cmdedit_set_initial_prompt(void)
 851 {
 852 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
 853         PS1 = NULL;
 854 #else
 855         PS1 = getenv("PS1");
 856         if(PS1==0)
 857                 PS1 = "\\w \\$ ";
 858 #endif
 859 }
 860
 861 static inline void setup_prompt_string(int promptmode, char **prompt_str)
 862 {
 863         debug_printf("setup_prompt_string %d ",promptmode);
 864 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
 865         /* Set up the prompt */
 866         if (promptmode == 1) {
 867                 free(PS1);
 868                 PS1=xmalloc(strlen(cwd)+4);
 869                 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
 870                 *prompt_str = PS1;
 871         } else {
 872                 *prompt_str = PS2;
 873         }
 874 #else
 875         *prompt_str = (promptmode==1)? PS1 : PS2;
 876 #endif
 877         debug_printf("result %s\n",*prompt_str);
 878 }
 879
 880 static void get_user_input(struct in_str *i)
 881 {
 882         char *prompt_str;
 883         static char the_command[BUFSIZ];
 884
 885         setup_prompt_string(i->promptmode, &prompt_str);
 886 #ifdef CONFIG_FEATURE_COMMAND_EDITING
 887         /*
 888          ** enable command line editing only while a command line
 889          ** is actually being read; otherwise, we'll end up bequeathing
 890          ** atexit() handlers and other unwanted stuff to our
 891          ** child processes (rob@sysgo.de)
 892          */
 893         cmdedit_read_input(prompt_str, the_command);
 894 #else
 895         fputs(prompt_str, stdout);
 896         fflush(stdout);
 897         the_command[0]=fgetc(i->file);
 898         the_command[1]='\0';
 899 #endif
 900         fflush(stdout);
 901         i->p = the_command;
 902 }
 903
 904 /* This is the magic location that prints prompts
 905  * and gets data back from the user */
 906 static int file_get(struct in_str *i)
 907 {
 908         int ch;
 909
 910         ch = 0;
 911         /* If there is data waiting, eat it up */
 912         if (i->p && *i->p) {
 913                 ch=*i->p++;
 914         } else {
 915                 /* need to double check i->file because we might be doing something
 916                  * more complicated by now, like sourcing or substituting. */
 917                 if (i->__promptme && interactive && i->file == stdin) {
 918                         while(! i->p || (interactive && strlen(i->p)==0) ) {
 919                                 get_user_input(i);
 920                         }
 921                         i->promptmode=2;
 922                         i->__promptme = 0;
 923                         if (i->p && *i->p) {
 924                                 ch=*i->p++;
 925                         }
 926                 } else {
 927                         ch = fgetc(i->file);
 928                 }
 929
 930                 debug_printf("b_getch: got a %d\n", ch);
 931         }
 932         if (ch == '\n') i->__promptme=1;
 933         return ch;
 934 }
 935
 936 /* All the callers guarantee this routine will never be
 937  * used right after a newline, so prompting is not needed.
 938  */
 939 static int file_peek(struct in_str *i)
 940 {
 941         if (i->p && *i->p) {
 942                 return *i->p;
 943         } else {
 944                 i->peek_buf[0] = fgetc(i->file);
 945                 i->peek_buf[1] = '\0';
 946                 i->p = i->peek_buf;
 947                 debug_printf("b_peek: got a %d\n", *i->p);
 948                 return *i->p;
 949         }
 950 }
 951
 952 static void setup_file_in_str(struct in_str *i, FILE *f)
 953 {
 954         i->peek = file_peek;
 955         i->get = file_get;
 956         i->__promptme=1;
 957         i->promptmode=1;
 958         i->file = f;
 959         i->p = NULL;
 960 }
 961
 962 static void setup_string_in_str(struct in_str *i, const char *s)
 963 {
 964         i->peek = static_peek;
 965         i->get = static_get;
 966         i->__promptme=1;
 967         i->promptmode=1;
 968         i->p = s;
 969 }
 970
 971 static void mark_open(int fd)
 972 {
 973         struct close_me *new = xmalloc(sizeof(struct close_me));
 974         new->fd = fd;
 975         new->next = close_me_head;
 976         close_me_head = new;
 977 }
 978
 979 static void mark_closed(int fd)
 980 {
 981         struct close_me *tmp;
 982         if (close_me_head == NULL || close_me_head->fd != fd)
 983                 bb_error_msg_and_die("corrupt close_me");
 984         tmp = close_me_head;
 985         close_me_head = close_me_head->next;
 986         free(tmp);
 987 }
 988
 989 static void close_all(void)
 990 {
 991         struct close_me *c;
 992         for (c=close_me_head; c; c=c->next) {
 993                 close(c->fd);
 994         }
 995         close_me_head = NULL;
 996 }
 997
 998 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
 999  * and stderr if they are redirected. */
1000 static int setup_redirects(struct child_prog *prog, int squirrel[])
1001 {
1002         int openfd, mode;
1003         struct redir_struct *redir;
1004
1005         for (redir=prog->redirects; redir; redir=redir->next) {
1006                 if (redir->dup == -1 && redir->word.gl_pathv == NULL) {
1007                         /* something went wrong in the parse.  Pretend it didn't happen */
1008                         continue;
1009                 }
1010                 if (redir->dup == -1) {
1011                         mode=redir_table[redir->type].mode;
1012                         openfd = open(redir->word.gl_pathv[0], mode, 0666);
1013                         if (openfd < 0) {
1014                         /* this could get lost if stderr has been redirected, but
1015                            bash and ash both lose it as well (though zsh doesn't!) */
1016                                 bb_perror_msg("error opening %s", redir->word.gl_pathv[0]);
1017                                 return 1;
1018                         }
1019                 } else {
1020                         openfd = redir->dup;
1021                 }
1022
1023                 if (openfd != redir->fd) {
1024                         if (squirrel && redir->fd < 3) {
1025                                 squirrel[redir->fd] = dup(redir->fd);
1026                         }
1027                         if (openfd == -3) {
1028                                 close(openfd);
1029                         } else {
1030                                 dup2(openfd, redir->fd);
1031                                 if (redir->dup == -1)
1032                                         close (openfd);
1033                         }
1034                 }
1035         }
1036         return 0;
1037 }
1038
1039 static void restore_redirects(int squirrel[])
1040 {
1041         int i, fd;
1042         for (i=0; i<3; i++) {
1043                 fd = squirrel[i];
1044                 if (fd != -1) {
1045                         /* No error checking.  I sure wouldn't know what
1046                          * to do with an error if I found one! */
1047                         dup2(fd, i);
1048                         close(fd);
1049                 }
1050         }
1051 }
1052
1053 /* never returns */
1054 /* XXX no exit() here.  If you don't exec, use _exit instead.
1055  * The at_exit handlers apparently confuse the calling process,
1056  * in particular stdin handling.  Not sure why? */
1057 static void pseudo_exec(struct child_prog *child)
1058 {
1059         int i, rcode;
1060         char *p;
1061         const struct built_in_command *x;
1062         if (child->argv) {
1063                 for (i=0; is_assignment(child->argv[i]); i++) {
1064                         debug_printf("pid %d environment modification: %s\n",getpid(),child->argv[i]);
1065                         p = insert_var_value(child->argv[i]);
1066                         putenv(strdup(p));
1067                         if (p != child->argv[i]) free(p);
1068                 }
1069                 child->argv+=i;  /* XXX this hack isn't so horrible, since we are about
1070                                         to exit, and therefore don't need to keep data
1071                                         structures consistent for free() use. */
1072                 /* If a variable is assigned in a forest, and nobody listens,
1073                  * was it ever really set?
1074                  */
1075                 if (child->argv[0] == NULL) {
1076                         _exit(EXIT_SUCCESS);
1077                 }
1078
1079                 /*
1080                  * Check if the command matches any of the builtins.
1081                  * Depending on context, this might be redundant.  But it's
1082                  * easier to waste a few CPU cycles than it is to figure out
1083                  * if this is one of those cases.
1084                  */
1085                 for (x = bltins; x->cmd; x++) {
1086                         if (strcmp(child->argv[0], x->cmd) == 0 ) {
1087                                 debug_printf("builtin exec %s\n", child->argv[0]);
1088                                 rcode = x->function(child);
1089                                 fflush(stdout);
1090                                 _exit(rcode);
1091                         }
1092                 }
1093
1094                 /* Check if the command matches any busybox internal commands
1095                  * ("applets") here.
1096                  * FIXME: This feature is not 100% safe, since
1097                  * BusyBox is not fully reentrant, so we have no guarantee the things
1098                  * from the .bss are still zeroed, or that things from .data are still
1099                  * at their defaults.  We could exec ourself from /proc/self/exe, but I
1100                  * really dislike relying on /proc for things.  We could exec ourself
1101                  * from global_argv[0], but if we are in a chroot, we may not be able
1102                  * to find ourself... */
1103 #ifdef CONFIG_FEATURE_SH_STANDALONE_SHELL
1104                 {
1105                         int argc_l;
1106                         char** argv_l=child->argv;
1107                         char *name = child->argv[0];
1108
1109                         /* Count argc for use in a second... */
1110                         for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1111                         optind = 1;
1112                         debug_printf("running applet %s\n", name);
1113                         run_applet_by_name(name, argc_l, child->argv);
1114                 }
1115 #endif
1116                 debug_printf("exec of %s\n",child->argv[0]);
1117                 execvp(child->argv[0],child->argv);
1118                 bb_perror_msg("couldn't exec: %s",child->argv[0]);
1119                 _exit(1);
1120         } else if (child->group) {
1121                 debug_printf("runtime nesting to group\n");
1122                 interactive=0;    /* crucial!!!! */
1123                 rcode = run_list_real(child->group);
1124                 /* OK to leak memory by not calling free_pipe_list,
1125                  * since this process is about to exit */
1126                 _exit(rcode);
1127         } else {
1128                 /* Can happen.  See what bash does with ">foo" by itself. */
1129                 debug_printf("trying to pseudo_exec null command\n");
1130                 _exit(EXIT_SUCCESS);
1131         }
1132 }
1133
1134 static void insert_bg_job(struct pipe *pi)
1135 {
1136         struct pipe *thejob;
1137
1138         /* Linear search for the ID of the job to use */
1139         pi->jobid = 1;
1140         for (thejob = job_list; thejob; thejob = thejob->next)
1141                 if (thejob->jobid >= pi->jobid)
1142                         pi->jobid = thejob->jobid + 1;
1143
1144         /* add thejob to the list of running jobs */
1145         if (!job_list) {
1146                 thejob = job_list = xmalloc(sizeof(*thejob));
1147         } else {
1148                 for (thejob = job_list; thejob->next; thejob = thejob->next) /* nothing */;
1149                 thejob->next = xmalloc(sizeof(*thejob));
1150                 thejob = thejob->next;
1151         }
1152
1153         /* physically copy the struct job */
1154         memcpy(thejob, pi, sizeof(struct pipe));
1155         thejob->next = NULL;
1156         thejob->running_progs = thejob->num_progs;
1157         thejob->stopped_progs = 0;
1158         thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */
1159
1160         //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1161         {
1162                 char *bar=thejob->text;
1163                 char **foo=pi->progs[0].argv;
1164                 while(foo && *foo) {
1165                         bar += sprintf(bar, "%s ", *foo++);
1166                 }
1167         }
1168
1169         /* we don't wait for background thejobs to return -- append it
1170            to the list of backgrounded thejobs and leave it alone */
1171         printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1172         last_bg_pid = thejob->progs[0].pid;
1173         last_jobid = thejob->jobid;
1174 }
1175
1176 /* remove a backgrounded job */
1177 static void remove_bg_job(struct pipe *pi)
1178 {
1179         struct pipe *prev_pipe;
1180
1181         if (pi == job_list) {
1182                 job_list = pi->next;
1183         } else {
1184                 prev_pipe = job_list;
1185                 while (prev_pipe->next != pi)
1186                         prev_pipe = prev_pipe->next;
1187                 prev_pipe->next = pi->next;
1188         }
1189         if (job_list)
1190                 last_jobid = job_list->jobid;
1191         else
1192                 last_jobid = 0;
1193
1194         pi->stopped_progs = 0;
1195         free_pipe(pi, 0);
1196         free(pi);
1197 }
1198
1199 /* Checks to see if any processes have exited -- if they
1200    have, figure out why and see if a job has completed */
1201 static int checkjobs(struct pipe* fg_pipe)
1202 {
1203         int attributes;
1204         int status;
1205         int prognum = 0;
1206         struct pipe *pi;
1207         pid_t childpid;
1208
1209         attributes = WUNTRACED;
1210         if (fg_pipe==NULL) {
1211                 attributes |= WNOHANG;
1212         }
1213
1214         while ((childpid = waitpid(-1, &status, attributes)) > 0) {
1215                 if (fg_pipe) {
1216                         int i, rcode = 0;
1217                         for (i=0; i < fg_pipe->num_progs; i++) {
1218                                 if (fg_pipe->progs[i].pid == childpid) {
1219                                         if (i==fg_pipe->num_progs-1)
1220                                                 rcode=WEXITSTATUS(status);
1221                                         (fg_pipe->num_progs)--;
1222                                         return(rcode);
1223                                 }
1224                         }
1225                 }
1226
1227                 for (pi = job_list; pi; pi = pi->next) {
1228                         prognum = 0;
1229                         while (prognum < pi->num_progs && pi->progs[prognum].pid != childpid) {
1230                                 prognum++;
1231                         }
1232                         if (prognum < pi->num_progs)
1233                                 break;
1234                 }
1235
1236                 if(pi==NULL) {
1237                         debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
1238                         continue;
1239                 }
1240
1241                 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1242                         /* child exited */
1243                         pi->running_progs--;
1244                         pi->progs[prognum].pid = 0;
1245
1246                         if (!pi->running_progs) {
1247                                 printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
1248                                 remove_bg_job(pi);
1249                         }
1250                 } else {
1251                         /* child stopped */
1252                         pi->stopped_progs++;
1253                         pi->progs[prognum].is_stopped = 1;
1254
1255 #if 0
1256                         /* Printing this stuff is a pain, since it tends to
1257                          * overwrite the prompt an inconveinient moments.  So
1258                          * don't do that.  */
1259                         if (pi->stopped_progs == pi->num_progs) {
1260                                 printf("\n"JOB_STATUS_FORMAT, pi->jobid, "Stopped", pi->text);
1261                         }
1262 #endif
1263                 }
1264         }
1265
1266         if (childpid == -1 && errno != ECHILD)
1267                 bb_perror_msg("waitpid");
1268
1269         /* move the shell to the foreground */
1270         //if (interactive && tcsetpgrp(shell_terminal, getpgid(0)))
1271         //      bb_perror_msg("tcsetpgrp-2");
1272         return -1;
1273 }
1274
1275 /* Figure out our controlling tty, checking in order stderr,
1276  * stdin, and stdout.  If check_pgrp is set, also check that
1277  * we belong to the foreground process group associated with
1278  * that tty.  The value of shell_terminal is needed in order to call
1279  * tcsetpgrp(shell_terminal, ...); */
1280 #if 0
1281 static void controlling_tty(int check_pgrp)
1282 {
1283         pid_t curpgrp;
1284
1285         if ((curpgrp = tcgetpgrp(shell_terminal = 2)) < 0
1286                         && (curpgrp = tcgetpgrp(shell_terminal = 0)) < 0
1287                         && (curpgrp = tcgetpgrp(shell_terminal = 1)) < 0)
1288                 goto shell_terminal_error;
1289
1290         if (check_pgrp && curpgrp != getpgid(0))
1291                 goto shell_terminal_error;
1292
1293         return;
1294
1295 shell_terminal_error:
1296                 shell_terminal = -1;
1297                 return;
1298 }
1299 #endif
1300
1301 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1302  * to finish.  See checkjobs().
1303  *
1304  * return code is normally -1, when the caller has to wait for children
1305  * to finish to determine the exit status of the pipe.  If the pipe
1306  * is a simple builtin command, however, the action is done by the
1307  * time run_pipe_real returns, and the exit code is provided as the
1308  * return value.
1309  *
1310  * The input of the pipe is always stdin, the output is always
1311  * stdout.  The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1312  * because it tries to avoid running the command substitution in
1313  * subshell, when that is in fact necessary.  The subshell process
1314  * now has its stdout directed to the input of the appropriate pipe,
1315  * so this routine is noticeably simpler.
1316  */
1317 static int run_pipe_real(struct pipe *pi)
1318 {
1319         int i;
1320         int nextin, nextout;
1321         int pipefds[2];                         /* pipefds[0] is for reading */
1322         struct child_prog *child;
1323         const struct built_in_command *x;
1324         char *p;
1325
1326         nextin = 0;
1327         pi->pgrp = -1;
1328
1329         /* Check if this is a simple builtin (not part of a pipe).
1330          * Builtins within pipes have to fork anyway, and are handled in
1331          * pseudo_exec.  "echo foo | read bar" doesn't work on bash, either.
1332          */
1333         if (pi->num_progs == 1) child = & (pi->progs[0]);
1334         if (pi->num_progs == 1 && child->group && child->subshell == 0) {
1335                 int squirrel[] = {-1, -1, -1};
1336                 int rcode;
1337                 debug_printf("non-subshell grouping\n");
1338                 setup_redirects(child, squirrel);
1339                 /* XXX could we merge code with following builtin case,
1340                  * by creating a pseudo builtin that calls run_list_real? */
1341                 rcode = run_list_real(child->group);
1342                 restore_redirects(squirrel);
1343                 return rcode;
1344         } else if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1345                 for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
1346                 if (i!=0 && child->argv[i]==NULL) {
1347                         /* assignments, but no command: set the local environment */
1348                         for (i=0; child->argv[i]!=NULL; i++) {
1349
1350                                 /* Ok, this case is tricky.  We have to decide if this is a
1351                                  * local variable, or an already exported variable.  If it is
1352                                  * already exported, we have to export the new value.  If it is
1353                                  * not exported, we need only set this as a local variable.
1354                                  * This junk is all to decide whether or not to export this
1355                                  * variable. */
1356                                 int export_me=0;
1357                                 char *name, *value;
1358                                 name = bb_xstrdup(child->argv[i]);
1359                                 debug_printf("Local environment set: %s\n", name);
1360                                 value = strchr(name, '=');
1361                                 if (value)
1362                                         *value=0;
1363                                 if ( get_local_var(name)) {
1364                                         export_me=1;
1365                                 }
1366                                 free(name);
1367                                 p = insert_var_value(child->argv[i]);
1368                                 set_local_var(p, export_me);
1369                                 if (p != child->argv[i]) free(p);
1370                         }
1371                         return EXIT_SUCCESS;   /* don't worry about errors in set_local_var() yet */
1372                 }
1373                 for (i = 0; is_assignment(child->argv[i]); i++) {
1374                         p = insert_var_value(child->argv[i]);
1375                         putenv(strdup(p));
1376                         if (p != child->argv[i]) {
1377                                 child->sp--;
1378                                 free(p);
1379                         }
1380                 }
1381                 if (child->sp) {
1382                         char * str = NULL;
1383
1384                         str = make_string((child->argv + i));
1385                         parse_string_outer(str, FLAG_EXIT_FROM_LOOP | FLAG_REPARSING);
1386                         free(str);
1387                         return last_return_code;
1388                 }
1389                 for (x = bltins; x->cmd; x++) {
1390                         if (strcmp(child->argv[i], x->cmd) == 0 ) {
1391                                 int squirrel[] = {-1, -1, -1};
1392                                 int rcode;
1393                                 if (x->function == builtin_exec && child->argv[i+1]==NULL) {
1394                                         debug_printf("magic exec\n");
1395                                         setup_redirects(child,NULL);
1396                                         return EXIT_SUCCESS;
1397                                 }
1398                                 debug_printf("builtin inline %s\n", child->argv[0]);
1399                                 /* XXX setup_redirects acts on file descriptors, not FILEs.
1400                                  * This is perfect for work that comes after exec().
1401                                  * Is it really safe for inline use?  Experimentally,
1402                                  * things seem to work with glibc. */
1403                                 setup_redirects(child, squirrel);
1404                                 child->argv+=i;  /* XXX horrible hack */
1405                                 rcode = x->function(child);
1406                                 child->argv-=i;  /* XXX restore hack so free() can work right */
1407                                 restore_redirects(squirrel);
1408                                 return rcode;
1409                         }
1410                 }
1411         }
1412
1413         for (i = 0; i < pi->num_progs; i++) {
1414                 child = & (pi->progs[i]);
1415
1416                 /* pipes are inserted between pairs of commands */
1417                 if ((i + 1) < pi->num_progs) {
1418                         if (pipe(pipefds)<0) bb_perror_msg_and_die("pipe");
1419                         nextout = pipefds[1];
1420                 } else {
1421                         nextout=1;
1422                         pipefds[0] = -1;
1423                 }
1424
1425                 /* XXX test for failed fork()? */
1426 #if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
1427                 if (!(child->pid = fork()))
1428 #else
1429                 if (!(child->pid = vfork()))
1430 #endif
1431                 {
1432                         /* Set the handling for job control signals back to the default.  */
1433                         signal(SIGINT, SIG_DFL);
1434                         signal(SIGQUIT, SIG_DFL);
1435                         signal(SIGTERM, SIG_DFL);
1436                         signal(SIGTSTP, SIG_DFL);
1437                         signal(SIGTTIN, SIG_DFL);
1438                         signal(SIGTTOU, SIG_DFL);
1439                         signal(SIGCHLD, SIG_DFL);
1440
1441                         close_all();
1442
1443                         if (nextin != 0) {
1444                                 dup2(nextin, 0);
1445                                 close(nextin);
1446                         }
1447                         if (nextout != 1) {
1448                                 dup2(nextout, 1);
1449                                 close(nextout);
1450                         }
1451                         if (pipefds[0]!=-1) {
1452                                 close(pipefds[0]);  /* opposite end of our output pipe */
1453                         }
1454
1455                         /* Like bash, explicit redirects override pipes,
1456                          * and the pipe fd is available for dup'ing. */
1457                         setup_redirects(child,NULL);
1458
1459                         if (interactive && pi->followup!=PIPE_BG) {
1460                                 /* If we (the child) win the race, put ourselves in the process
1461                                  * group whose leader is the first process in this pipe. */
1462                                 if (pi->pgrp < 0) {
1463                                         pi->pgrp = getpid();
1464                                 }
1465                                 if (setpgid(0, pi->pgrp) == 0) {
1466                                         tcsetpgrp(2, pi->pgrp);
1467                                 }
1468                         }
1469
1470                         pseudo_exec(child);
1471                 }
1472
1473
1474                 /* put our child in the process group whose leader is the
1475                    first process in this pipe */
1476                 if (pi->pgrp < 0) {
1477                         pi->pgrp = child->pid;
1478                 }
1479                 /* Don't check for errors.  The child may be dead already,
1480                  * in which case setpgid returns error code EACCES. */
1481                 setpgid(child->pid, pi->pgrp);
1482
1483                 if (nextin != 0)
1484                         close(nextin);
1485                 if (nextout != 1)
1486                         close(nextout);
1487
1488                 /* If there isn't another process, nextin is garbage
1489                    but it doesn't matter */
1490                 nextin = pipefds[0];
1491         }
1492         return -1;
1493 }
1494
1495 static int run_list_real(struct pipe *pi)
1496 {
1497         char *save_name = NULL;
1498         char **list = NULL;
1499         char **save_list = NULL;
1500         struct pipe *rpipe;
1501         int flag_rep = 0;
1502         int save_num_progs;
1503         int rcode=0, flag_skip=1;
1504         int flag_restore = 0;
1505         int if_code=0, next_if_code=0;  /* need double-buffer to handle elif */
1506         reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1507         /* check syntax for "for" */
1508         for (rpipe = pi; rpipe; rpipe = rpipe->next) {
1509                 if ((rpipe->r_mode == RES_IN ||
1510                     rpipe->r_mode == RES_FOR) &&
1511                     (rpipe->next == NULL)) {
1512                                 syntax();
1513                                 return 1;
1514                 }
1515                 if ((rpipe->r_mode == RES_IN &&
1516                         (rpipe->next->r_mode == RES_IN &&
1517                         rpipe->next->progs->argv != NULL))||
1518                         (rpipe->r_mode == RES_FOR &&
1519                         rpipe->next->r_mode != RES_IN)) {
1520                                 syntax();
1521                                 return 1;
1522                 }
1523         }
1524         for (; pi; pi = (flag_restore != 0) ? rpipe : pi->next) {
1525                 if (pi->r_mode == RES_WHILE || pi->r_mode == RES_UNTIL ||
1526                         pi->r_mode == RES_FOR) {
1527                                 flag_restore = 0;
1528                                 if (!rpipe) {
1529                                         flag_rep = 0;
1530                                         rpipe = pi;
1531                                 }
1532                 }
1533                 rmode = pi->r_mode;
1534                 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);
1535                 if (rmode == skip_more_in_this_rmode && flag_skip) {
1536                         if (pi->followup == PIPE_SEQ) flag_skip=0;
1537                         continue;
1538                 }
1539                 flag_skip = 1;
1540                 skip_more_in_this_rmode = RES_XXXX;
1541                 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1542                 if (rmode == RES_THEN &&  if_code) continue;
1543                 if (rmode == RES_ELSE && !if_code) continue;
1544                 if (rmode == RES_ELIF && !if_code) break;
1545                 if (rmode == RES_FOR && pi->num_progs) {
1546                         if (!list) {
1547                                 /* if no variable values after "in" we skip "for" */
1548                                 if (!pi->next->progs->argv) continue;
1549                                 /* create list of variable values */
1550                                 list = make_list_in(pi->next->progs->argv,
1551                                         pi->progs->argv[0]);
1552                                 save_list = list;
1553                                 save_name = pi->progs->argv[0];
1554                                 pi->progs->argv[0] = NULL;
1555                                 flag_rep = 1;
1556                         }
1557                         if (!(*list)) {
1558                                 free(pi->progs->argv[0]);
1559                                 free(save_list);
1560                                 list = NULL;
1561                                 flag_rep = 0;
1562                                 pi->progs->argv[0] = save_name;
1563                                 pi->progs->glob_result.gl_pathv[0] =
1564                                         pi->progs->argv[0];
1565                                 continue;
1566                         } else {
1567                                 /* insert new value from list for variable */
1568                                 if (pi->progs->argv[0])
1569                                         free(pi->progs->argv[0]);
1570                                 pi->progs->argv[0] = *list++;
1571                                 pi->progs->glob_result.gl_pathv[0] =
1572                                         pi->progs->argv[0];
1573                         }
1574                 }
1575                 if (rmode == RES_IN) continue;
1576                 if (rmode == RES_DO) {
1577                         if (!flag_rep) continue;
1578                 }
1579                 if ((rmode == RES_DONE)) {
1580                         if (flag_rep) {
1581                                 flag_restore = 1;
1582                         } else {
1583                                 rpipe = NULL;
1584                         }
1585                 }
1586                 if (pi->num_progs == 0) continue;
1587                 save_num_progs = pi->num_progs; /* save number of programs */
1588                 rcode = run_pipe_real(pi);
1589                 debug_printf("run_pipe_real returned %d\n",rcode);
1590                 if (rcode!=-1) {
1591                         /* We only ran a builtin: rcode was set by the return value
1592                          * of run_pipe_real(), and we don't need to wait for anything. */
1593                 } else if (pi->followup==PIPE_BG) {
1594                         /* XXX check bash's behavior with nontrivial pipes */
1595                         /* XXX compute jobid */
1596                         /* XXX what does bash do with attempts to background builtins? */
1597                         insert_bg_job(pi);
1598                         rcode = EXIT_SUCCESS;
1599                 } else {
1600                         if (interactive) {
1601                                 /* move the new process group into the foreground */
1602                                 if (tcsetpgrp(shell_terminal, pi->pgrp) && errno != ENOTTY)
1603                                         bb_perror_msg("tcsetpgrp-3");
1604                                 rcode = checkjobs(pi);
1605                                 /* move the shell to the foreground */
1606                                 if (tcsetpgrp(shell_terminal, getpgid(0)) && errno != ENOTTY)
1607                                         bb_perror_msg("tcsetpgrp-4");
1608                         } else {
1609                                 rcode = checkjobs(pi);
1610                         }
1611                         debug_printf("checkjobs returned %d\n",rcode);
1612                 }
1613                 last_return_code=rcode;
1614                 pi->num_progs = save_num_progs; /* restore number of programs */
1615                 if ( rmode == RES_IF || rmode == RES_ELIF )
1616                         next_if_code=rcode;  /* can be overwritten a number of times */
1617                 if (rmode == RES_WHILE)
1618                         flag_rep = !last_return_code;
1619                 if (rmode == RES_UNTIL)
1620                         flag_rep = last_return_code;
1621                 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1622                      (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1623                         skip_more_in_this_rmode=rmode;
1624                 checkjobs(NULL);
1625         }
1626         return rcode;
1627 }
1628
1629 /* broken, of course, but OK for testing */
1630 static char *indenter(int i)
1631 {
1632         static char blanks[]="                                    ";
1633         return &blanks[sizeof(blanks)-i-1];
1634 }
1635
1636 /* return code is the exit status of the pipe */
1637 static int free_pipe(struct pipe *pi, int indent)
1638 {
1639         char **p;
1640         struct child_prog *child;
1641         struct redir_struct *r, *rnext;
1642         int a, i, ret_code=0;
1643         char *ind = indenter(indent);
1644
1645         if (pi->stopped_progs > 0)
1646                 return ret_code;
1647         final_printf("%s run pipe: (pid %d)\n",ind,getpid());
1648         for (i=0; i<pi->num_progs; i++) {
1649                 child = &pi->progs[i];
1650                 final_printf("%s  command %d:\n",ind,i);
1651                 if (child->argv) {
1652                         for (a=0,p=child->argv; *p; a++,p++) {
1653                                 final_printf("%s   argv[%d] = %s\n",ind,a,*p);
1654                         }
1655                         globfree(&child->glob_result);
1656                         child->argv=NULL;
1657                 } else if (child->group) {
1658                         final_printf("%s   begin group (subshell:%d)\n",ind, child->subshell);
1659                         ret_code = free_pipe_list(child->group,indent+3);
1660                         final_printf("%s   end group\n",ind);
1661                 } else {
1662                         final_printf("%s   (nil)\n",ind);
1663                 }
1664                 for (r=child->redirects; r; r=rnext) {
1665                         final_printf("%s   redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
1666                         if (r->dup == -1) {
1667                                 /* guard against the case >$FOO, where foo is unset or blank */
1668                                 if (r->word.gl_pathv) {
1669                                         final_printf(" %s\n", *r->word.gl_pathv);
1670                                         globfree(&r->word);
1671                                 }
1672                         } else {
1673                                 final_printf("&%d\n", r->dup);
1674                         }
1675                         rnext=r->next;
1676                         free(r);
1677                 }
1678                 child->redirects=NULL;
1679         }
1680         free(pi->progs);   /* children are an array, they get freed all at once */
1681         pi->progs=NULL;
1682         return ret_code;
1683 }
1684
1685 static int free_pipe_list(struct pipe *head, int indent)
1686 {
1687         int rcode=0;   /* if list has no members */
1688         struct pipe *pi, *next;
1689         char *ind = indenter(indent);
1690         for (pi=head; pi; pi=next) {
1691                 final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
1692                 rcode = free_pipe(pi, indent);
1693                 final_printf("%s pipe followup code %d\n", ind, pi->followup);
1694                 next=pi->next;
1695                 pi->next=NULL;
1696                 free(pi);
1697         }
1698         return rcode;
1699 }
1700
1701 /* Select which version we will use */
1702 static int run_list(struct pipe *pi)
1703 {
1704         int rcode=0;
1705         if (fake_mode==0) {
1706                 rcode = run_list_real(pi);
1707         }
1708         /* free_pipe_list has the side effect of clearing memory
1709          * In the long run that function can be merged with run_list_real,
1710          * but doing that now would hobble the debugging effort. */
1711         free_pipe_list(pi,0);
1712         return rcode;
1713 }
1714
1715 /* The API for glob is arguably broken.  This routine pushes a non-matching
1716  * string into the output structure, removing non-backslashed backslashes.
1717  * If someone can prove me wrong, by performing this function within the
1718  * original glob(3) api, feel free to rewrite this routine into oblivion.
1719  * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1720  * XXX broken if the last character is '\\', check that before calling.
1721  */
1722 static int globhack(const char *src, int flags, glob_t *pglob)
1723 {
1724         int cnt=0, pathc;
1725         const char *s;
1726         char *dest;
1727         for (cnt=1, s=src; s && *s; s++) {
1728                 if (*s == '\\') s++;
1729                 cnt++;
1730         }
1731         dest = malloc(cnt);
1732         if (!dest) return GLOB_NOSPACE;
1733         if (!(flags & GLOB_APPEND)) {
1734                 pglob->gl_pathv=NULL;
1735                 pglob->gl_pathc=0;
1736                 pglob->gl_offs=0;
1737                 pglob->gl_offs=0;
1738         }
1739         pathc = ++pglob->gl_pathc;
1740         pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1741         if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1742         pglob->gl_pathv[pathc-1]=dest;
1743         pglob->gl_pathv[pathc]=NULL;
1744         for (s=src; s && *s; s++, dest++) {
1745                 if (*s == '\\') s++;
1746                 *dest = *s;
1747         }
1748         *dest='\0';
1749         return 0;
1750 }
1751
1752 /* XXX broken if the last character is '\\', check that before calling */
1753 static int glob_needed(const char *s)
1754 {
1755         for (; *s; s++) {
1756                 if (*s == '\\') s++;
1757                 if (strchr("*[?",*s)) return 1;
1758         }
1759         return 0;
1760 }
1761
1762 #if 0
1763 static void globprint(glob_t *pglob)
1764 {
1765         int i;
1766         debug_printf("glob_t at %p:\n", pglob);
1767         debug_printf("  gl_pathc=%d  gl_pathv=%p  gl_offs=%d  gl_flags=%d\n",
1768                 pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
1769         for (i=0; i<pglob->gl_pathc; i++)
1770                 debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
1771                         pglob->gl_pathv[i], pglob->gl_pathv[i]);
1772 }
1773 #endif
1774
1775 static int xglob(o_string *dest, int flags, glob_t *pglob)
1776 {
1777         int gr;
1778
1779         /* short-circuit for null word */
1780         /* we can code this better when the debug_printf's are gone */
1781         if (dest->length == 0) {
1782                 if (dest->nonnull) {
1783                         /* bash man page calls this an "explicit" null */
1784                         gr = globhack(dest->data, flags, pglob);
1785                         debug_printf("globhack returned %d\n",gr);
1786                 } else {
1787                         return 0;
1788                 }
1789         } else if (glob_needed(dest->data)) {
1790                 gr = glob(dest->data, flags, NULL, pglob);
1791                 debug_printf("glob returned %d\n",gr);
1792                 if (gr == GLOB_NOMATCH) {
1793                         /* quote removal, or more accurately, backslash removal */
1794                         gr = globhack(dest->data, flags, pglob);
1795                         debug_printf("globhack returned %d\n",gr);
1796                 }
1797         } else {
1798                 gr = globhack(dest->data, flags, pglob);
1799                 debug_printf("globhack returned %d\n",gr);
1800         }
1801         if (gr == GLOB_NOSPACE)
1802                 bb_error_msg_and_die("out of memory during glob");
1803         if (gr != 0) { /* GLOB_ABORTED ? */
1804                 bb_error_msg("glob(3) error %d",gr);
1805         }
1806         /* globprint(glob_target); */
1807         return gr;
1808 }
1809
1810 /* This is used to get/check local shell variables */
1811 static char *get_local_var(const char *s)
1812 {
1813         struct variables *cur;
1814
1815         if (!s)
1816                 return NULL;
1817         for (cur = top_vars; cur; cur=cur->next)
1818                 if(strcmp(cur->name, s)==0)
1819                         return cur->value;
1820         return NULL;
1821 }
1822
1823 /* This is used to set local shell variables
1824    flg_export==0 if only local (not exporting) variable
1825    flg_export==1 if "new" exporting environ
1826    flg_export>1  if current startup environ (not call putenv()) */
1827 static int set_local_var(const char *s, int flg_export)
1828 {
1829         char *name, *value;
1830         int result=0;
1831         struct variables *cur;
1832
1833         name=strdup(s);
1834
1835         /* Assume when we enter this function that we are already in
1836          * NAME=VALUE format.  So the first order of business is to
1837          * split 's' on the '=' into 'name' and 'value' */
1838         value = strchr(name, '=');
1839         if (value==0 && ++value==0) {
1840                 free(name);
1841                 return -1;
1842         }
1843         *value++ = 0;
1844
1845         for(cur = top_vars; cur; cur = cur->next) {
1846                 if(strcmp(cur->name, name)==0)
1847                         break;
1848         }
1849
1850         if(cur) {
1851                 if(strcmp(cur->value, value)==0) {
1852                         if(flg_export>0 && cur->flg_export==0)
1853                                 cur->flg_export=flg_export;
1854                         else
1855                                 result++;
1856                 } else {
1857                         if(cur->flg_read_only) {
1858                                 bb_error_msg("%s: readonly variable", name);
1859                                 result = -1;
1860                         } else {
1861                                 if(flg_export>0 || cur->flg_export>1)
1862                                         cur->flg_export=1;
1863                                 free(cur->value);
1864
1865                                 cur->value = strdup(value);
1866                         }
1867                 }
1868         } else {
1869                 cur = malloc(sizeof(struct variables));
1870                 if(!cur) {
1871                         result = -1;
1872                 } else {
1873                         cur->name = strdup(name);
1874                         if(cur->name == 0) {
1875                                 free(cur);
1876                                 result = -1;
1877                         } else {
1878                                 struct variables *bottom = top_vars;
1879                                 cur->value = strdup(value);
1880                                 cur->next = 0;
1881                                 cur->flg_export = flg_export;
1882                                 cur->flg_read_only = 0;
1883                                 while(bottom->next) bottom=bottom->next;
1884                                 bottom->next = cur;
1885                         }
1886                 }
1887         }
1888
1889         if(result==0 && cur->flg_export==1) {
1890                 *(value-1) = '=';
1891                 result = putenv(name);
1892         } else {
1893                 free(name);
1894                 if(result>0)            /* equivalent to previous set */
1895                         result = 0;
1896         }
1897         return result;
1898 }
1899
1900 static void unset_local_var(const char *name)
1901 {
1902         struct variables *cur;
1903
1904         if (name) {
1905                 for (cur = top_vars; cur; cur=cur->next) {
1906                         if(strcmp(cur->name, name)==0)
1907                                 break;
1908                 }
1909                 if(cur!=0) {
1910                         struct variables *next = top_vars;
1911                         if(cur->flg_read_only) {
1912                                 bb_error_msg("%s: readonly variable", name);
1913                                 return;
1914                         } else {
1915                                 if(cur->flg_export)
1916                                         unsetenv(cur->name);
1917                                 free(cur->name);
1918                                 free(cur->value);
1919                                 while (next->next != cur)
1920                                         next = next->next;
1921                                 next->next = cur->next;
1922                         }
1923                         free(cur);
1924                 }
1925         }
1926 }
1927
1928 static int is_assignment(const char *s)
1929 {
1930         if (s==NULL || !isalpha(*s)) return 0;
1931         ++s;
1932         while(isalnum(*s) || *s=='_') ++s;
1933         return *s=='=';
1934 }
1935
1936 /* the src parameter allows us to peek forward to a possible &n syntax
1937  * for file descriptor duplication, e.g., "2>&1".
1938  * Return code is 0 normally, 1 if a syntax error is detected in src.
1939  * Resource errors (in xmalloc) cause the process to exit */
1940 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1941         struct in_str *input)
1942 {
1943         struct child_prog *child=ctx->child;
1944         struct redir_struct *redir = child->redirects;
1945         struct redir_struct *last_redir=NULL;
1946
1947         /* Create a new redir_struct and drop it onto the end of the linked list */
1948         while(redir) {
1949                 last_redir=redir;
1950                 redir=redir->next;
1951         }
1952         redir = xmalloc(sizeof(struct redir_struct));
1953         redir->next=NULL;
1954         redir->word.gl_pathv=NULL;
1955         if (last_redir) {
1956                 last_redir->next=redir;
1957         } else {
1958                 child->redirects=redir;
1959         }
1960
1961         redir->type=style;
1962         redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1963
1964         debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1965
1966         /* Check for a '2>&1' type redirect */
1967         redir->dup = redirect_dup_num(input);
1968         if (redir->dup == -2) return 1;  /* syntax error */
1969         if (redir->dup != -1) {
1970                 /* Erik had a check here that the file descriptor in question
1971                  * is legit; I postpone that to "run time"
1972                  * A "-" representation of "close me" shows up as a -3 here */
1973                 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
1974         } else {
1975                 /* We do _not_ try to open the file that src points to,
1976                  * since we need to return and let src be expanded first.
1977                  * Set ctx->pending_redirect, so we know what to do at the
1978                  * end of the next parsed word.
1979                  */
1980                 ctx->pending_redirect = redir;
1981         }
1982         return 0;
1983 }
1984
1985 static struct pipe *new_pipe(void) {
1986         struct pipe *pi;
1987         pi = xmalloc(sizeof(struct pipe));
1988         pi->num_progs = 0;
1989         pi->progs = NULL;
1990         pi->next = NULL;
1991         pi->followup = 0;  /* invalid */
1992         pi->r_mode = RES_NONE;
1993         return pi;
1994 }
1995
1996 static void initialize_context(struct p_context *ctx)
1997 {
1998         ctx->pipe=NULL;
1999         ctx->pending_redirect=NULL;
2000         ctx->child=NULL;
2001         ctx->list_head=new_pipe();
2002         ctx->pipe=ctx->list_head;
2003         ctx->w=RES_NONE;
2004         ctx->stack=NULL;
2005         ctx->old_flag=0;
2006         done_command(ctx);   /* creates the memory for working child */
2007 }
2008
2009 /* normal return is 0
2010  * if a reserved word is found, and processed, return 1
2011  * should handle if, then, elif, else, fi, for, while, until, do, done.
2012  * case, function, and select are obnoxious, save those for later.
2013  */
2014 static int reserved_word(o_string *dest, struct p_context *ctx)
2015 {
2016         struct reserved_combo {
2017                 char *literal;
2018                 int code;
2019                 long flag;
2020         };
2021         /* Mostly a list of accepted follow-up reserved words.
2022          * FLAG_END means we are done with the sequence, and are ready
2023          * to turn the compound list into a command.
2024          * FLAG_START means the word must start a new compound list.
2025          */
2026         static struct reserved_combo reserved_list[] = {
2027                 { "if",    RES_IF,    FLAG_THEN | FLAG_START },
2028                 { "then",  RES_THEN,  FLAG_ELIF | FLAG_ELSE | FLAG_FI },
2029                 { "elif",  RES_ELIF,  FLAG_THEN },
2030                 { "else",  RES_ELSE,  FLAG_FI   },
2031                 { "fi",    RES_FI,    FLAG_END  },
2032                 { "for",   RES_FOR,   FLAG_IN   | FLAG_START },
2033                 { "while", RES_WHILE, FLAG_DO   | FLAG_START },
2034                 { "until", RES_UNTIL, FLAG_DO   | FLAG_START },
2035                 { "in",    RES_IN,    FLAG_DO   },
2036                 { "do",    RES_DO,    FLAG_DONE },
2037                 { "done",  RES_DONE,  FLAG_END  }
2038         };
2039         struct reserved_combo *r;
2040         for (r=reserved_list;
2041 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
2042                 r<reserved_list+NRES; r++) {
2043                 if (strcmp(dest->data, r->literal) == 0) {
2044                         debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
2045                         if (r->flag & FLAG_START) {
2046                                 struct p_context *new = xmalloc(sizeof(struct p_context));
2047                                 debug_printf("push stack\n");
2048                                 if (ctx->w == RES_IN || ctx->w == RES_FOR) {
2049                                         syntax();
2050                                         free(new);
2051                                         ctx->w = RES_SNTX;
2052                                         b_reset(dest);
2053                                         return 1;
2054                                 }
2055                                 *new = *ctx;   /* physical copy */
2056                                 initialize_context(ctx);
2057                                 ctx->stack=new;
2058                         } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
2059                                 syntax();
2060                                 ctx->w = RES_SNTX;
2061                                 b_reset(dest);
2062                                 return 1;
2063                         }
2064                         ctx->w=r->code;
2065                         ctx->old_flag = r->flag;
2066                         if (ctx->old_flag & FLAG_END) {
2067                                 struct p_context *old;
2068                                 debug_printf("pop stack\n");
2069                                 done_pipe(ctx,PIPE_SEQ);
2070                                 old = ctx->stack;
2071                                 old->child->group = ctx->list_head;
2072                                 old->child->subshell = 0;
2073                                 *ctx = *old;   /* physical copy */
2074                                 free(old);
2075                         }
2076                         b_reset (dest);
2077                         return 1;
2078                 }
2079         }
2080         return 0;
2081 }
2082
2083 /* normal return is 0.
2084  * Syntax or xglob errors return 1. */
2085 static int done_word(o_string *dest, struct p_context *ctx)
2086 {
2087         struct child_prog *child=ctx->child;
2088         glob_t *glob_target;
2089         int gr, flags = 0;
2090
2091         debug_printf("done_word: %s %p\n", dest->data, child);
2092         if (dest->length == 0 && !dest->nonnull) {
2093                 debug_printf("  true null, ignored\n");
2094                 return 0;
2095         }
2096         if (ctx->pending_redirect) {
2097                 glob_target = &ctx->pending_redirect->word;
2098         } else {
2099                 if (child->group) {
2100                         syntax();
2101                         return 1;  /* syntax error, groups and arglists don't mix */
2102                 }
2103                 if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) {
2104                         debug_printf("checking %s for reserved-ness\n",dest->data);
2105                         if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
2106                 }
2107                 glob_target = &child->glob_result;
2108                 if (child->argv) flags |= GLOB_APPEND;
2109         }
2110         gr = xglob(dest, flags, glob_target);
2111         if (gr != 0) return 1;
2112
2113         b_reset(dest);
2114         if (ctx->pending_redirect) {
2115                 ctx->pending_redirect=NULL;
2116                 if (glob_target->gl_pathc != 1) {
2117                         bb_error_msg("ambiguous redirect");
2118                         return 1;
2119                 }
2120         } else {
2121                 child->argv = glob_target->gl_pathv;
2122         }
2123         if (ctx->w == RES_FOR) {
2124                 done_word(dest,ctx);
2125                 done_pipe(ctx,PIPE_SEQ);
2126         }
2127         return 0;
2128 }
2129
2130 /* The only possible error here is out of memory, in which case
2131  * xmalloc exits. */
2132 static int done_command(struct p_context *ctx)
2133 {
2134         /* The child is really already in the pipe structure, so
2135          * advance the pipe counter and make a new, null child.
2136          * Only real trickiness here is that the uncommitted
2137          * child structure, to which ctx->child points, is not
2138          * counted in pi->num_progs. */
2139         struct pipe *pi=ctx->pipe;
2140         struct child_prog *prog=ctx->child;
2141
2142         if (prog && prog->group == NULL
2143                  && prog->argv == NULL
2144                  && prog->redirects == NULL) {
2145                 debug_printf("done_command: skipping null command\n");
2146                 return 0;
2147         } else if (prog) {
2148                 pi->num_progs++;
2149                 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
2150         } else {
2151                 debug_printf("done_command: initializing\n");
2152         }
2153         pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
2154
2155         prog = pi->progs + pi->num_progs;
2156         prog->redirects = NULL;
2157         prog->argv = NULL;
2158         prog->is_stopped = 0;
2159         prog->group = NULL;
2160         prog->glob_result.gl_pathv = NULL;
2161         prog->family = pi;
2162         prog->sp = 0;
2163         ctx->child = prog;
2164         prog->type = ctx->type;
2165
2166         /* but ctx->pipe and ctx->list_head remain unchanged */
2167         return 0;
2168 }
2169
2170 static int done_pipe(struct p_context *ctx, pipe_style type)
2171 {
2172         struct pipe *new_p;
2173         done_command(ctx);  /* implicit closure of previous command */
2174         debug_printf("done_pipe, type %d\n", type);
2175         ctx->pipe->followup = type;
2176         ctx->pipe->r_mode = ctx->w;
2177         new_p=new_pipe();
2178         ctx->pipe->next = new_p;
2179         ctx->pipe = new_p;
2180         ctx->child = NULL;
2181         done_command(ctx);  /* set up new pipe to accept commands */
2182         return 0;
2183 }
2184
2185 /* peek ahead in the in_str to find out if we have a "&n" construct,
2186  * as in "2>&1", that represents duplicating a file descriptor.
2187  * returns either -2 (syntax error), -1 (no &), or the number found.
2188  */
2189 static int redirect_dup_num(struct in_str *input)
2190 {
2191         int ch, d=0, ok=0;
2192         ch = b_peek(input);
2193         if (ch != '&') return -1;
2194
2195         b_getch(input);  /* get the & */
2196         ch=b_peek(input);
2197         if (ch == '-') {
2198                 b_getch(input);
2199                 return -3;  /* "-" represents "close me" */
2200         }
2201         while (isdigit(ch)) {
2202                 d = d*10+(ch-'0');
2203                 ok=1;
2204                 b_getch(input);
2205                 ch = b_peek(input);
2206         }
2207         if (ok) return d;
2208
2209         bb_error_msg("ambiguous redirect");
2210         return -2;
2211 }
2212
2213 /* If a redirect is immediately preceded by a number, that number is
2214  * supposed to tell which file descriptor to redirect.  This routine
2215  * looks for such preceding numbers.  In an ideal world this routine
2216  * needs to handle all the following classes of redirects...
2217  *     echo 2>foo     # redirects fd  2 to file "foo", nothing passed to echo
2218  *     echo 49>foo    # redirects fd 49 to file "foo", nothing passed to echo
2219  *     echo -2>foo    # redirects fd  1 to file "foo",    "-2" passed to echo
2220  *     echo 49x>foo   # redirects fd  1 to file "foo",   "49x" passed to echo
2221  * A -1 output from this program means no valid number was found, so the
2222  * caller should use the appropriate default for this redirection.
2223  */
2224 static int redirect_opt_num(o_string *o)
2225 {
2226         int num;
2227
2228         if (o->length==0) return -1;
2229         for(num=0; num<o->length; num++) {
2230                 if (!isdigit(*(o->data+num))) {
2231                         return -1;
2232                 }
2233         }
2234         /* reuse num (and save an int) */
2235         num=atoi(o->data);
2236         b_reset(o);
2237         return num;
2238 }
2239
2240 static FILE *generate_stream_from_list(struct pipe *head)
2241 {
2242         FILE *pf;
2243         int pid, channel[2];
2244         if (pipe(channel)<0) bb_perror_msg_and_die("pipe");
2245 #if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
2246         pid=fork();
2247 #else
2248         pid=vfork();
2249 #endif
2250         if (pid<0) {
2251                 bb_perror_msg_and_die("fork");
2252         } else if (pid==0) {
2253                 close(channel[0]);
2254                 if (channel[1] != 1) {
2255                         dup2(channel[1],1);
2256                         close(channel[1]);
2257                 }
2258 #if 0
2259 #define SURROGATE "surrogate response"
2260                 write(1,SURROGATE,sizeof(SURROGATE));
2261                 _exit(run_list(head));
2262 #else
2263                 _exit(run_list_real(head));   /* leaks memory */
2264 #endif
2265         }
2266         debug_printf("forked child %d\n",pid);
2267         close(channel[1]);
2268         pf = fdopen(channel[0],"r");
2269         debug_printf("pipe on FILE *%p\n",pf);
2270         return pf;
2271 }
2272
2273 /* this version hacked for testing purposes */
2274 /* return code is exit status of the process that is run. */
2275 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2276 {
2277         int retcode;
2278         o_string result=NULL_O_STRING;
2279         struct p_context inner;
2280         FILE *p;
2281         struct in_str pipe_str;
2282         initialize_context(&inner);
2283
2284         /* recursion to generate command */
2285         retcode = parse_stream(&result, &inner, input, subst_end);
2286         if (retcode != 0) return retcode;  /* syntax error or EOF */
2287         done_word(&result, &inner);
2288         done_pipe(&inner, PIPE_SEQ);
2289         b_free(&result);
2290
2291         p=generate_stream_from_list(inner.list_head);
2292         if (p==NULL) return 1;
2293         mark_open(fileno(p));
2294         setup_file_in_str(&pipe_str, p);
2295
2296         /* now send results of command back into original context */
2297         retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2298         /* XXX In case of a syntax error, should we try to kill the child?
2299          * That would be tough to do right, so just read until EOF. */
2300         if (retcode == 1) {
2301                 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
2302         }
2303
2304         debug_printf("done reading from pipe, pclose()ing\n");
2305         /* This is the step that wait()s for the child.  Should be pretty
2306          * safe, since we just read an EOF from its stdout.  We could try
2307          * to better, by using wait(), and keeping track of background jobs
2308          * at the same time.  That would be a lot of work, and contrary
2309          * to the KISS philosophy of this program. */
2310         mark_closed(fileno(p));
2311         retcode=pclose(p);
2312         free_pipe_list(inner.list_head,0);
2313         debug_printf("pclosed, retcode=%d\n",retcode);
2314         /* XXX this process fails to trim a single trailing newline */
2315         return retcode;
2316 }
2317
2318 static int parse_group(o_string *dest, struct p_context *ctx,
2319         struct in_str *input, int ch)
2320 {
2321         int rcode, endch=0;
2322         struct p_context sub;
2323         struct child_prog *child = ctx->child;
2324         if (child->argv) {
2325                 syntax();
2326                 return 1;  /* syntax error, groups and arglists don't mix */
2327         }
2328         initialize_context(&sub);
2329         switch(ch) {
2330                 case '(': endch=')'; child->subshell=1; break;
2331                 case '{': endch='}'; break;
2332                 default: syntax();   /* really logic error */
2333         }
2334         rcode=parse_stream(dest,&sub,input,endch);
2335         done_word(dest,&sub); /* finish off the final word in the subcontext */
2336         done_pipe(&sub, PIPE_SEQ);  /* and the final command there, too */
2337         child->group = sub.list_head;
2338         return rcode;
2339         /* child remains "open", available for possible redirects */
2340 }
2341
2342 /* basically useful version until someone wants to get fancier,
2343  * see the bash man page under "Parameter Expansion" */
2344 static char *lookup_param(char *src)
2345 {
2346         char *p=NULL;
2347         if (src) {
2348                 p = getenv(src);
2349                 if (!p)
2350                         p = get_local_var(src);
2351         }
2352         return p;
2353 }
2354
2355 /* return code: 0 for OK, 1 for syntax error */
2356 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2357 {
2358         int i, advance=0;
2359         char sep[]=" ";
2360         int ch = input->peek(input);  /* first character after the $ */
2361         debug_printf("handle_dollar: ch=%c\n",ch);
2362         if (isalpha(ch)) {
2363                 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2364                 ctx->child->sp++;
2365                 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
2366                         b_getch(input);
2367                         b_addchr(dest,ch);
2368                 }
2369                 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2370         } else if (isdigit(ch)) {
2371                 i = ch-'0';  /* XXX is $0 special? */
2372                 if (i<global_argc) {
2373                         parse_string(dest, ctx, global_argv[i]); /* recursion */
2374                 }
2375                 advance = 1;
2376         } else switch (ch) {
2377                 case '$':
2378                         b_adduint(dest,getpid());
2379                         advance = 1;
2380                         break;
2381                 case '!':
2382                         if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2383                         advance = 1;
2384                         break;
2385                 case '?':
2386                         b_adduint(dest,last_return_code);
2387                         advance = 1;
2388                         break;
2389                 case '#':
2390                         b_adduint(dest,global_argc ? global_argc-1 : 0);
2391                         advance = 1;
2392                         break;
2393                 case '{':
2394                         b_addchr(dest, SPECIAL_VAR_SYMBOL);
2395                         ctx->child->sp++;
2396                         b_getch(input);
2397                         /* XXX maybe someone will try to escape the '}' */
2398                         while(ch=b_getch(input),ch!=EOF && ch!='}') {
2399                                 b_addchr(dest,ch);
2400                         }
2401                         if (ch != '}') {
2402                                 syntax();
2403                                 return 1;
2404                         }
2405                         b_addchr(dest, SPECIAL_VAR_SYMBOL);
2406                         break;
2407                 case '(':
2408                         b_getch(input);
2409                         process_command_subs(dest, ctx, input, ')');
2410                         break;
2411                 case '*':
2412                         sep[0]=ifs[0];
2413                         for (i=1; i<global_argc; i++) {
2414                                 parse_string(dest, ctx, global_argv[i]);
2415                                 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2416                         }
2417                         break;
2418                 case '@':
2419                 case '-':
2420                 case '_':
2421                         /* still unhandled, but should be eventually */
2422                         bb_error_msg("unhandled syntax: $%c",ch);
2423                         return 1;
2424                         break;
2425                 default:
2426                         b_addqchr(dest,'$',dest->quote);
2427         }
2428         /* Eat the character if the flag was set.  If the compiler
2429          * is smart enough, we could substitute "b_getch(input);"
2430          * for all the "advance = 1;" above, and also end up with
2431          * a nice size-optimized program.  Hah!  That'll be the day.
2432          */
2433         if (advance) b_getch(input);
2434         return 0;
2435 }
2436
2437 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2438 {
2439         struct in_str foo;
2440         setup_string_in_str(&foo, src);
2441         return parse_stream(dest, ctx, &foo, '\0');
2442 }
2443
2444 /* return code is 0 for normal exit, 1 for syntax error */
2445 int parse_stream(o_string *dest, struct p_context *ctx,
2446         struct in_str *input, int end_trigger)
2447 {
2448         int ch, m;
2449         int redir_fd;
2450         redir_type redir_style;
2451         int next;
2452
2453         /* Only double-quote state is handled in the state variable dest->quote.
2454          * A single-quote triggers a bypass of the main loop until its mate is
2455          * found.  When recursing, quote state is passed in via dest->quote. */
2456
2457         debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2458         while ((ch=b_getch(input))!=EOF) {
2459                 m = map[ch];
2460                 next = (ch == '\n') ? 0 : b_peek(input);
2461                 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2462                         ch,ch,m,dest->quote);
2463                 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2464                         b_addqchr(dest, ch, dest->quote);
2465                 } else {
2466                         if (m==2) {  /* unquoted IFS */
2467                                 if (done_word(dest, ctx)) {
2468                                         return 1;
2469                                 }
2470                                 /* If we aren't performing a substitution, treat a newline as a
2471                                  * command separator.  */
2472                                 if (end_trigger != '\0' && ch=='\n')
2473                                         done_pipe(ctx,PIPE_SEQ);
2474                         }
2475                         if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2476                                 debug_printf("leaving parse_stream (triggered)\n");
2477                                 return 0;
2478                         }
2479 #if 0
2480                         if (ch=='\n') {
2481                                 /* Yahoo!  Time to run with it! */
2482                                 done_pipe(ctx,PIPE_SEQ);
2483                                 run_list(ctx->list_head);
2484                                 initialize_context(ctx);
2485                         }
2486 #endif
2487                         if (m!=2) switch (ch) {
2488                 case '#':
2489                         if (dest->length == 0 && !dest->quote) {
2490                                 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2491                         } else {
2492                                 b_addqchr(dest, ch, dest->quote);
2493                         }
2494                         break;
2495                 case '\\':
2496                         if (next == EOF) {
2497                                 syntax();
2498                                 return 1;
2499                         }
2500                         b_addqchr(dest, '\\', dest->quote);
2501                         b_addqchr(dest, b_getch(input), dest->quote);
2502                         break;
2503                 case '$':
2504                         if (handle_dollar(dest, ctx, input)!=0) return 1;
2505                         break;
2506                 case '\'':
2507                         dest->nonnull = 1;
2508                         while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2509                                 b_addchr(dest,ch);
2510                         }
2511                         if (ch==EOF) {
2512                                 syntax();
2513                                 return 1;
2514                         }
2515                         break;
2516                 case '"':
2517                         dest->nonnull = 1;
2518                         dest->quote = !dest->quote;
2519                         break;
2520                 case '`':
2521                         process_command_subs(dest, ctx, input, '`');
2522                         break;
2523                 case '>':
2524                         redir_fd = redirect_opt_num(dest);
2525                         done_word(dest, ctx);
2526                         redir_style=REDIRECT_OVERWRITE;
2527                         if (next == '>') {
2528                                 redir_style=REDIRECT_APPEND;
2529                                 b_getch(input);
2530                         } else if (next == '(') {
2531                                 syntax();   /* until we support >(list) Process Substitution */
2532                                 return 1;
2533                         }
2534                         setup_redirect(ctx, redir_fd, redir_style, input);
2535                         break;
2536                 case '<':
2537                         redir_fd = redirect_opt_num(dest);
2538                         done_word(dest, ctx);
2539                         redir_style=REDIRECT_INPUT;
2540                         if (next == '<') {
2541                                 redir_style=REDIRECT_HEREIS;
2542                                 b_getch(input);
2543                         } else if (next == '>') {
2544                                 redir_style=REDIRECT_IO;
2545                                 b_getch(input);
2546                         } else if (next == '(') {
2547                                 syntax();   /* until we support <(list) Process Substitution */
2548                                 return 1;
2549                         }
2550                         setup_redirect(ctx, redir_fd, redir_style, input);
2551                         break;
2552                 case ';':
2553                         done_word(dest, ctx);
2554                         done_pipe(ctx,PIPE_SEQ);
2555                         break;
2556                 case '&':
2557                         done_word(dest, ctx);
2558                         if (next=='&') {
2559                                 b_getch(input);
2560                                 done_pipe(ctx,PIPE_AND);
2561                         } else {
2562                                 done_pipe(ctx,PIPE_BG);
2563                         }
2564                         break;
2565                 case '|':
2566                         done_word(dest, ctx);
2567                         if (next=='|') {
2568                                 b_getch(input);
2569                                 done_pipe(ctx,PIPE_OR);
2570                         } else {
2571                                 /* we could pick up a file descriptor choice here
2572                                  * with redirect_opt_num(), but bash doesn't do it.
2573                                  * "echo foo 2| cat" yields "foo 2". */
2574                                 done_command(ctx);
2575                         }
2576                         break;
2577                 case '(':
2578                 case '{':
2579                         if (parse_group(dest, ctx, input, ch)!=0) return 1;
2580                         break;
2581                 case ')':
2582                 case '}':
2583                         syntax();   /* Proper use of this character caught by end_trigger */
2584                         return 1;
2585                         break;
2586                 default:
2587                         syntax();   /* this is really an internal logic error */
2588                         return 1;
2589                         }
2590                 }
2591         }
2592         /* complain if quote?  No, maybe we just finished a command substitution
2593          * that was quoted.  Example:
2594          * $ echo "`cat foo` plus more"
2595          * and we just got the EOF generated by the subshell that ran "cat foo"
2596          * The only real complaint is if we got an EOF when end_trigger != '\0',
2597          * that is, we were really supposed to get end_trigger, and never got
2598          * one before the EOF.  Can't use the standard "syntax error" return code,
2599          * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2600         debug_printf("leaving parse_stream (EOF)\n");
2601         if (end_trigger != '\0') return -1;
2602         return 0;
2603 }
2604
2605 static void mapset(const char *set, int code)
2606 {
2607         const unsigned char *s;
2608         for (s = (const unsigned char *)set; *s; s++) map[(int)*s] = code;
2609 }
2610
2611 static void update_ifs_map(void)
2612 {
2613         /* char *ifs and char map[256] are both globals. */
2614         ifs = getenv("IFS");
2615         if (ifs == NULL) ifs=" \t\n";
2616         /* Precompute a list of 'flow through' behavior so it can be treated
2617          * quickly up front.  Computation is necessary because of IFS.
2618          * Special case handling of IFS == " \t\n" is not implemented.
2619          * The map[] array only really needs two bits each, and on most machines
2620          * that would be faster because of the reduced L1 cache footprint.
2621          */
2622         memset(map,0,sizeof(map)); /* most characters flow through always */
2623         mapset("\\$'\"`", 3);      /* never flow through */
2624         mapset("<>;&|(){}#", 1);   /* flow through if quoted */
2625         mapset(ifs, 2);            /* also flow through if quoted */
2626 }
2627
2628 /* most recursion does not come through here, the exception is
2629  * from builtin_source() */
2630 int parse_stream_outer(struct in_str *inp, int flag)
2631 {
2632
2633         struct p_context ctx;
2634         o_string temp=NULL_O_STRING;
2635         int rcode;
2636         do {
2637                 ctx.type = flag;
2638                 initialize_context(&ctx);
2639                 update_ifs_map();
2640                 if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING)) mapset(";$&|", 0);
2641                 inp->promptmode=1;
2642                 rcode = parse_stream(&temp, &ctx, inp, '\n');
2643                 if (rcode != 1 && ctx.old_flag != 0) {
2644                         syntax();
2645                 }
2646                 if (rcode != 1 && ctx.old_flag == 0) {
2647                         done_word(&temp, &ctx);
2648                         done_pipe(&ctx,PIPE_SEQ);
2649                         run_list(ctx.list_head);
2650                 } else {
2651                         if (ctx.old_flag != 0) {
2652                                 free(ctx.stack);
2653                                 b_reset(&temp);
2654                         }
2655                         temp.nonnull = 0;
2656                         temp.quote = 0;
2657                         inp->p = NULL;
2658                         free_pipe_list(ctx.list_head,0);
2659                 }
2660                 b_free(&temp);
2661         } while (rcode != -1 && !(flag & FLAG_EXIT_FROM_LOOP));   /* loop on syntax errors, return on EOF */
2662         return 0;
2663 }
2664
2665 static int parse_string_outer(const char *s, int flag)
2666 {
2667         struct in_str input;
2668         setup_string_in_str(&input, s);
2669         return parse_stream_outer(&input, flag);
2670 }
2671
2672 static int parse_file_outer(FILE *f)
2673 {
2674         int rcode;
2675         struct in_str input;
2676         setup_file_in_str(&input, f);
2677         rcode = parse_stream_outer(&input, FLAG_PARSE_SEMICOLON);
2678         return rcode;
2679 }
2680
2681 /* Make sure we have a controlling tty.  If we get started under a job
2682  * aware app (like bash for example), make sure we are now in charge so
2683  * we don't fight over who gets the foreground */
2684 static void setup_job_control(void)
2685 {
2686         static pid_t shell_pgrp;
2687         /* Loop until we are in the foreground.  */
2688         while (tcgetpgrp (shell_terminal) != (shell_pgrp = getpgrp ()))
2689                 kill (- shell_pgrp, SIGTTIN);
2690
2691         /* Ignore interactive and job-control signals.  */
2692         signal(SIGINT, SIG_IGN);
2693         signal(SIGQUIT, SIG_IGN);
2694         signal(SIGTERM, SIG_IGN);
2695         signal(SIGTSTP, SIG_IGN);
2696         signal(SIGTTIN, SIG_IGN);
2697         signal(SIGTTOU, SIG_IGN);
2698         signal(SIGCHLD, SIG_IGN);
2699
2700         /* Put ourselves in our own process group.  */
2701         setsid();
2702         shell_pgrp = getpid ();
2703         setpgid (shell_pgrp, shell_pgrp);
2704
2705         /* Grab control of the terminal.  */
2706         tcsetpgrp(shell_terminal, shell_pgrp);
2707 }
2708
2709 int hush_main(int argc, char **argv)
2710 {
2711         int opt;
2712         FILE *input;
2713         char **e = environ;
2714
2715         /* XXX what should these be while sourcing /etc/profile? */
2716         global_argc = argc;
2717         global_argv = argv;
2718
2719         /* (re?) initialize globals.  Sometimes hush_main() ends up calling
2720          * hush_main(), therefore we cannot rely on the BSS to zero out this
2721          * stuff.  Reset these to 0 every time. */
2722         ifs = NULL;
2723         /* map[] is taken care of with call to update_ifs_map() */
2724         fake_mode = 0;
2725         interactive = 0;
2726         close_me_head = NULL;
2727         last_bg_pid = 0;
2728         job_list = NULL;
2729         last_jobid = 0;
2730
2731         /* Initialize some more globals to non-zero values */
2732         set_cwd();
2733 #ifdef CONFIG_FEATURE_COMMAND_EDITING
2734         cmdedit_set_initial_prompt();
2735 #else
2736         PS1 = NULL;
2737 #endif
2738         PS2 = "> ";
2739
2740         /* initialize our shell local variables with the values
2741          * currently living in the environment */
2742         if (e) {
2743                 for (; *e; e++)
2744                         set_local_var(*e, 2);   /* without call putenv() */
2745         }
2746
2747         last_return_code=EXIT_SUCCESS;
2748
2749
2750         if (argv[0] && argv[0][0] == '-') {
2751                 debug_printf("\nsourcing /etc/profile\n");
2752                 if ((input = fopen("/etc/profile", "r")) != NULL) {
2753                         mark_open(fileno(input));
2754                         parse_file_outer(input);
2755                         mark_closed(fileno(input));
2756                         fclose(input);
2757                 }
2758         }
2759         input=stdin;
2760
2761         while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2762                 switch (opt) {
2763                         case 'c':
2764                                 {
2765                                         global_argv = argv+optind;
2766                                         global_argc = argc-optind;
2767                                         opt = parse_string_outer(optarg, FLAG_PARSE_SEMICOLON);
2768                                         goto final_return;
2769                                 }
2770                                 break;
2771                         case 'i':
2772                                 interactive++;
2773                                 break;
2774                         case 'f':
2775                                 fake_mode++;
2776                                 break;
2777                         default:
2778 #ifndef BB_VER
2779                                 fprintf(stderr, "Usage: sh [FILE]...\n"
2780                                                 "   or: sh -c command [args]...\n\n");
2781                                 exit(EXIT_FAILURE);
2782 #else
2783                                 bb_show_usage();
2784 #endif
2785                 }
2786         }
2787         /* A shell is interactive if the `-i' flag was given, or if all of
2788          * the following conditions are met:
2789          *        no -c command
2790          *    no arguments remaining or the -s flag given
2791          *    standard input is a terminal
2792          *    standard output is a terminal
2793          *    Refer to Posix.2, the description of the `sh' utility. */
2794         if (argv[optind]==NULL && input==stdin &&
2795                         isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
2796                 interactive++;
2797         }
2798
2799         debug_printf("\ninteractive=%d\n", interactive);
2800         if (interactive) {
2801                 /* Looks like they want an interactive shell */
2802 #ifndef CONFIG_FEATURE_SH_EXTRA_QUIET
2803                 printf( "\n\n%s hush - the humble shell v0.01 (testing)\n",
2804                         BB_BANNER);
2805                 printf( "Enter 'help' for a list of built-in commands.\n\n");
2806 #endif
2807                 setup_job_control();
2808         }
2809
2810         if (argv[optind]==NULL) {
2811                 opt=parse_file_outer(stdin);
2812                 goto final_return;
2813         }
2814
2815         debug_printf("\nrunning script '%s'\n", argv[optind]);
2816         global_argv = argv+optind;
2817         global_argc = argc-optind;
2818         input = bb_xfopen(argv[optind], "r");
2819         opt = parse_file_outer(input);
2820
2821 #ifdef CONFIG_FEATURE_CLEAN_UP
2822         fclose(input);
2823         if (cwd && cwd != bb_msg_unknown)
2824                 free((char*)cwd);
2825         {
2826                 struct variables *cur, *tmp;
2827                 for(cur = top_vars; cur; cur = tmp) {
2828                         tmp = cur->next;
2829                         if (!cur->flg_read_only) {
2830                                 free(cur->name);
2831                                 free(cur->value);
2832                                 free(cur);
2833                         }
2834                 }
2835         }
2836 #endif
2837
2838 final_return:
2839         return(opt?opt:last_return_code);
2840 }
2841
2842 static char *insert_var_value(char *inp)
2843 {
2844         int res_str_len = 0;
2845         int len;
2846         int done = 0;
2847         char *p, *p1, *res_str = NULL;
2848
2849         while ((p = strchr(inp, SPECIAL_VAR_SYMBOL))) {
2850                 if (p != inp) {
2851                         len = p - inp;
2852                         res_str = xrealloc(res_str, (res_str_len + len));
2853                         strncpy((res_str + res_str_len), inp, len);
2854                         res_str_len += len;
2855                 }
2856                 inp = ++p;
2857                 p = strchr(inp, SPECIAL_VAR_SYMBOL);
2858                 *p = '\0';
2859                 if ((p1 = lookup_param(inp))) {
2860                         len = res_str_len + strlen(p1);
2861                         res_str = xrealloc(res_str, (1 + len));
2862                         strcpy((res_str + res_str_len), p1);
2863                         res_str_len = len;
2864                 }
2865                 *p = SPECIAL_VAR_SYMBOL;
2866                 inp = ++p;
2867                 done = 1;
2868         }
2869         if (done) {
2870                 res_str = xrealloc(res_str, (1 + res_str_len + strlen(inp)));
2871                 strcpy((res_str + res_str_len), inp);
2872                 while ((p = strchr(res_str, '\n'))) {
2873                         *p = ' ';
2874                 }
2875         }
2876         return (res_str == NULL) ? inp : res_str;
2877 }
2878
2879 static char **make_list_in(char **inp, char *name)
2880 {
2881         int len, i;
2882         int name_len = strlen(name);
2883         int n = 0;
2884         char **list;
2885         char *p1, *p2, *p3;
2886
2887         /* create list of variable values */
2888         list = xmalloc(sizeof(*list));
2889         for (i = 0; inp[i]; i++) {
2890                 p3 = insert_var_value(inp[i]);
2891                 p1 = p3;
2892                 while (*p1) {
2893                         if ((*p1 == ' ')) {
2894                                 p1++;
2895                                 continue;
2896                         }
2897                         if ((p2 = strchr(p1, ' '))) {
2898                                 len = p2 - p1;
2899                         } else {
2900                                 len = strlen(p1);
2901                                 p2 = p1 + len;
2902                         }
2903                         /* we use n + 2 in realloc for list,because we add
2904                          * new element and then we will add NULL element */
2905                         list = xrealloc(list, sizeof(*list) * (n + 2));
2906                         list[n] = xmalloc(2 + name_len + len);
2907                         strcpy(list[n], name);
2908                         strcat(list[n], "=");
2909                         strncat(list[n], p1, len);
2910                         list[n++][name_len + len + 1] = '\0';
2911                         p1 = p2;
2912                 }
2913                 if (p3 != inp[i]) free(p3);
2914         }
2915         list[n] = NULL;
2916         return list;
2917 }
2918
2919 /* Make new string for parser */
2920 static char * make_string(char ** inp)
2921 {
2922         char *p;
2923         char *str = NULL;
2924         int n;
2925         int len = 2;
2926
2927         for (n = 0; inp[n]; n++) {
2928                 p = insert_var_value(inp[n]);
2929                 str = xrealloc(str, (len + strlen(p)));
2930                 if (n) {
2931                         strcat(str, " ");
2932                 } else {
2933                         *str = '\0';
2934                 }
2935                 strcat(str, p);
2936                 len = strlen(str) + 3;
2937                 if (p != inp[n]) free(p);
2938         }
2939         len = strlen(str);
2940         *(str + len) = '\n';
2941         *(str + len + 1) = '\0';
2942         return str;
2943 }