findutils/xargs.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini xargs implementation for busybox
   4  * Options are supported: "-prtx -n max_arg -s max_chars -e[ouf_str]"
   5  *
   6  * (C) 2002,2003 by Vladimir Oleynik <dzo@simtreas.ru>
   7  *
   8  * Special thanks
   9  * - Mark Whitley and Glenn McGrath for stimulus to rewrite :)
  10  * - Mike Rendell <michael@cs.mun.ca>
  11  * and David MacKenzie <djm@gnu.ai.mit.edu>.
  12  *
  13  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  14  *
  15  * xargs is described in the Single Unix Specification v3 at
  16  * http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html
  17  *
  18  */
  19
  20 #include "busybox.h"
  21
  22 /* This is a NOEXEC applet. Be very careful! */
  23
  24
  25 /* COMPAT:  SYSV version defaults size (and has a max value of) to 470.
  26    We try to make it as large as possible. */
  27 #if !defined(ARG_MAX) && defined(_SC_ARG_MAX)
  28 #define ARG_MAX sysconf (_SC_ARG_MAX)
  29 #endif
  30 #ifndef ARG_MAX
  31 #define ARG_MAX 470
  32 #endif
  33
  34
  35 #ifdef TEST
  36 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
  37 #  define ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION 1
  38 # endif
  39 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
  40 #  define ENABLE_FEATURE_XARGS_SUPPORT_QUOTES 1
  41 # endif
  42 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
  43 #  define ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT 1
  44 # endif
  45 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
  46 #  define ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM 1
  47 # endif
  48 #endif
  49
  50 /*
  51    This function has special algorithm.
  52    Don't use fork and include to main!
  53 */
  54 static int xargs_exec(char **args)
  55 {
  56         int status;
  57
  58         status = spawn_and_wait(args);
  59         if (status < 0) {
  60                 bb_perror_msg("%s", args[0]);
  61                 return errno == ENOENT ? 127 : 126;
  62         }
  63         if (status == 255) {
  64                 bb_error_msg("%s: exited with status 255; aborting", args[0]);
  65                 return 124;
  66         }
  67 /* Huh? I think we won't see this, ever. We don't wait with WUNTRACED!
  68         if (WIFSTOPPED(status)) {
  69                 bb_error_msg("%s: stopped by signal %d",
  70                         args[0], WSTOPSIG(status));
  71                 return 125;
  72         }
  73 */
  74         if (status >= 1000) {
  75                 bb_error_msg("%s: terminated by signal %d",
  76                         args[0], status - 1000);
  77                 return 125;
  78         }
  79         if (status)
  80                 return 123;
  81         return 0;
  82 }
  83
  84
  85 typedef struct xlist_t {
  86         char *data;
  87         size_t length;
  88         struct xlist_t *link;
  89 } xlist_t;
  90
  91 static smallint eof_stdin_detected;
  92
  93 #define ISBLANK(c) ((c) == ' ' || (c) == '\t')
  94 #define ISSPACE(c) (ISBLANK(c) || (c) == '\n' || (c) == '\r' \
  95                     || (c) == '\f' || (c) == '\v')
  96
  97 #if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
  98 static xlist_t *process_stdin(xlist_t *list_arg,
  99         const char *eof_str, size_t mc, char *buf)
 100 {
 101 #define NORM      0
 102 #define QUOTE     1
 103 #define BACKSLASH 2
 104 #define SPACE     4
 105
 106         char *s = NULL;         /* start word */
 107         char *p = NULL;         /* pointer to end word */
 108         char q = 0;             /* quote char */
 109         char state = NORM;
 110         char eof_str_detected = 0;
 111         size_t line_l = 0;      /* size loaded args line */
 112         int c;                  /* current char */
 113         xlist_t *cur;
 114         xlist_t *prev;
 115
 116         prev = cur = list_arg;
 117         while (1) {
 118                 if (!cur) break;
 119                 prev = cur;
 120                 line_l += cur->length;
 121                 cur = cur->link;
 122         }
 123
 124         while (!eof_stdin_detected) {
 125                 c = getchar();
 126                 if (c == EOF) {
 127                         eof_stdin_detected = 1;
 128                         if (s)
 129                                 goto unexpected_eof;
 130                         break;
 131                 }
 132                 if (eof_str_detected)
 133                         continue;
 134                 if (state == BACKSLASH) {
 135                         state = NORM;
 136                         goto set;
 137                 } else if (state == QUOTE) {
 138                         if (c == q) {
 139                                 q = 0;
 140                                 state = NORM;
 141                         } else {
 142                                 goto set;
 143                         }
 144                 } else { /* if (state == NORM) */
 145                         if (ISSPACE(c)) {
 146                                 if (s) {
 147 unexpected_eof:
 148                                         state = SPACE;
 149                                         c = 0;
 150                                         goto set;
 151                                 }
 152                         } else {
 153                                 if (s == NULL)
 154                                         s = p = buf;
 155                                 if (c == '\\') {
 156                                         state = BACKSLASH;
 157                                 } else if (c == '\'' || c == '"') {
 158                                         q = c;
 159                                         state = QUOTE;
 160                                 } else {
 161 set:
 162                                         if ((size_t)(p - buf) >= mc)
 163                                                 bb_error_msg_and_die("argument line too long");
 164                                         *p++ = c;
 165                                 }
 166                         }
 167                 }
 168                 if (state == SPACE) {   /* word's delimiter or EOF detected */
 169                         if (q) {
 170                                 bb_error_msg_and_die("unmatched %s quote",
 171                                         q == '\'' ? "single" : "double");
 172                         }
 173                         /* word loaded */
 174                         if (eof_str) {
 175                                 eof_str_detected = (strcmp(s, eof_str) == 0);
 176                         }
 177                         if (!eof_str_detected) {
 178                                 size_t length = (p - buf);
 179 // TODO: smarter llist_t
 180                                 cur = xzalloc(sizeof(xlist_t) + length);
 181                                 cur->data = memcpy(cur + 1, s, length);
 182                                 cur->length = length;
 183                                 /*cur->link = NULL;*/
 184                                 if (prev == NULL) {
 185                                         list_arg = cur;
 186                                 } else {
 187                                         prev->link = cur;
 188                                 }
 189                                 prev = cur;
 190                                 line_l += length;
 191                                 if (line_l > mc) {
 192                                         /* stop memory usage :-) */
 193                                         break;
 194                                 }
 195                         }
 196                         s = NULL;
 197                         state = NORM;
 198                 }
 199         }
 200         return list_arg;
 201 }
 202 #else
 203 /* The variant does not support single quotes, double quotes or backslash */
 204 static xlist_t *process_stdin(xlist_t *list_arg,
 205                 const char *eof_str, size_t mc, char *buf)
 206 {
 207
 208         int c;                  /* current char */
 209         char eof_str_detected = 0;
 210         char *s = NULL;         /* start word */
 211         char *p = NULL;         /* pointer to end word */
 212         size_t line_l = 0;      /* size loaded args line */
 213         xlist_t *cur;
 214         xlist_t *prev;
 215
 216         prev = cur = list_arg;
 217         while (1) {
 218                 if (!cur) break;
 219                 prev = cur;
 220                 line_l += cur->length;
 221                 cur = cur->link;
 222         }
 223
 224         while (!eof_stdin_detected) {
 225                 c = getchar();
 226                 if (c == EOF) {
 227                         eof_stdin_detected = 1;
 228                 }
 229                 if (eof_str_detected)
 230                         continue;
 231                 if (c == EOF || ISSPACE(c)) {
 232                         if (s == NULL)
 233                                 continue;
 234                         c = EOF;
 235                 }
 236                 if (s == NULL)
 237                         s = p = buf;
 238                 if ((p - buf) >= mc)
 239                         bb_error_msg_and_die("argument line too long");
 240                 *p++ = c == EOF ? 0 : c;
 241                 if (c == EOF) { /* word's delimiter or EOF detected */
 242                         /* word loaded */
 243                         if (eof_str) {
 244                                 eof_str_detected = (strcmp(s, eof_str) == 0);
 245                         }
 246                         if (!eof_str_detected) {
 247                                 size_t length = (p - buf);
 248
 249                                 cur = xzalloc(sizeof(xlist_t) + length);
 250 // TODO: smarter llist_t
 251                                 cur->data = memcpy(cur + 1, s, length);
 252                                 cur->length = length;
 253                                 /*cur->link = NULL;*/
 254                                 if (prev == NULL) {
 255                                         list_arg = cur;
 256                                 } else {
 257                                         prev->link = cur;
 258                                 }
 259                                 prev = cur;
 260                                 line_l += length;
 261                                 if (line_l > mc) {
 262                                         /* stop memory usage :-) */
 263                                         break;
 264                                 }
 265                                 s = NULL;
 266                         }
 267                 }
 268         }
 269         return list_arg;
 270 }
 271 #endif /* FEATURE_XARGS_SUPPORT_QUOTES */
 272
 273
 274 #if ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
 275 /* Prompt the user for a response, and
 276    if the user responds affirmatively, return true;
 277    otherwise, return false. Uses "/dev/tty", not stdin. */
 278 static int xargs_ask_confirmation(void)
 279 {
 280         FILE *tty_stream;
 281         int c, savec;
 282
 283         tty_stream = xfopen(CURRENT_TTY, "r");
 284         fputs(" ?...", stderr);
 285         fflush(stderr);
 286         c = savec = getc(tty_stream);
 287         while (c != EOF && c != '\n')
 288                 c = getc(tty_stream);
 289         fclose(tty_stream);
 290         return (savec == 'y' || savec == 'Y');
 291 }
 292 #else
 293 # define xargs_ask_confirmation() 1
 294 #endif /* FEATURE_XARGS_SUPPORT_CONFIRMATION */
 295
 296 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
 297 static xlist_t *process0_stdin(xlist_t *list_arg,
 298                 const char *eof_str ATTRIBUTE_UNUSED, size_t mc, char *buf)
 299 {
 300         int c;                  /* current char */
 301         char *s = NULL;         /* start word */
 302         char *p = NULL;         /* pointer to end word */
 303         size_t line_l = 0;      /* size loaded args line */
 304         xlist_t *cur;
 305         xlist_t *prev;
 306
 307         prev = cur = list_arg;
 308         while (1) {
 309                 if (!cur) break;
 310                 prev = cur;
 311                 line_l += cur->length;
 312                 cur = cur->link;
 313         }
 314
 315         while (!eof_stdin_detected) {
 316                 c = getchar();
 317                 if (c == EOF) {
 318                         eof_stdin_detected = 1;
 319                         if (s == NULL)
 320                                 break;
 321                         c = 0;
 322                 }
 323                 if (s == NULL)
 324                         s = p = buf;
 325                 if ((size_t)(p - buf) >= mc)
 326                         bb_error_msg_and_die("argument line too long");
 327                 *p++ = c;
 328                 if (c == 0) {   /* word's delimiter or EOF detected */
 329                         /* word loaded */
 330                         size_t length = (p - buf);
 331
 332                         cur = xzalloc(sizeof(xlist_t) + length);
 333 // TODO: smarter llist_t
 334                         cur->data = memcpy(cur + 1, s, length);
 335                         cur->length = length;
 336                         /*cur->link = NULL;*/
 337                         if (prev == NULL) {
 338                                 list_arg = cur;
 339                         } else {
 340                                 prev->link = cur;
 341                         }
 342                         prev = cur;
 343                         line_l += length;
 344                         if (line_l > mc) {
 345                                 /* stop memory usage :-) */
 346                                 break;
 347                         }
 348                         s = NULL;
 349                 }
 350         }
 351         return list_arg;
 352 }
 353 #endif /* FEATURE_XARGS_SUPPORT_ZERO_TERM */
 354
 355 /* Correct regardless of combination of CONFIG_xxx */
 356 enum {
 357         OPTBIT_VERBOSE = 0,
 358         OPTBIT_NO_EMPTY,
 359         OPTBIT_UPTO_NUMBER,
 360         OPTBIT_UPTO_SIZE,
 361         OPTBIT_EOF_STRING,
 362         USE_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,)
 363         USE_FEATURE_XARGS_SUPPORT_TERMOPT(     OPTBIT_TERMINATE  ,)
 364         USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(   OPTBIT_ZEROTERM   ,)
 365
 366         OPT_VERBOSE     = 1<<OPTBIT_VERBOSE    ,
 367         OPT_NO_EMPTY    = 1<<OPTBIT_NO_EMPTY   ,
 368         OPT_UPTO_NUMBER = 1<<OPTBIT_UPTO_NUMBER,
 369         OPT_UPTO_SIZE   = 1<<OPTBIT_UPTO_SIZE  ,
 370         OPT_EOF_STRING  = 1<<OPTBIT_EOF_STRING ,
 371         OPT_INTERACTIVE = USE_FEATURE_XARGS_SUPPORT_CONFIRMATION((1<<OPTBIT_INTERACTIVE)) + 0,
 372         OPT_TERMINATE   = USE_FEATURE_XARGS_SUPPORT_TERMOPT(     (1<<OPTBIT_TERMINATE  )) + 0,
 373         OPT_ZEROTERM    = USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(   (1<<OPTBIT_ZEROTERM   )) + 0,
 374 };
 375 #define OPTION_STR "+trn:s:e::" \
 376         USE_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \
 377         USE_FEATURE_XARGS_SUPPORT_TERMOPT(     "x") \
 378         USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(   "0")
 379
 380 int xargs_main(int argc, char **argv);
 381 int xargs_main(int argc, char **argv)
 382 {
 383         char **args;
 384         int i, n;
 385         xlist_t *list = NULL;
 386         xlist_t *cur;
 387         int child_error = 0;
 388         char *max_args, *max_chars;
 389         int n_max_arg;
 390         size_t n_chars = 0;
 391         long orig_arg_max;
 392         const char *eof_str = "_";
 393         unsigned opt;
 394         size_t n_max_chars;
 395 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
 396         xlist_t* (*read_args)(xlist_t*, const char*, size_t, char*) = process_stdin;
 397 #else
 398 #define read_args process_stdin
 399 #endif
 400
 401         opt = getopt32(argc, argv, OPTION_STR, &max_args, &max_chars, &eof_str);
 402
 403         if (opt & OPT_ZEROTERM)
 404                 USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin);
 405
 406         argv += optind;
 407         argc -= optind;
 408         if (!argc) {
 409                 /* default behavior is to echo all the filenames */
 410                 *argv = (char*)"echo";
 411                 argc++;
 412         }
 413
 414         orig_arg_max = ARG_MAX;
 415         if (orig_arg_max == -1)
 416                 orig_arg_max = LONG_MAX;
 417         orig_arg_max -= 2048;   /* POSIX.2 requires subtracting 2048 */
 418
 419         if (opt & OPT_UPTO_SIZE) {
 420                 n_max_chars = xatoul_range(max_chars, 1, orig_arg_max);
 421                 for (i = 0; i < argc; i++) {
 422                         n_chars += strlen(*argv) + 1;
 423                 }
 424                 if (n_max_chars < n_chars) {
 425                         bb_error_msg_and_die("cannot fit single argument within argument list size limit");
 426                 }
 427                 n_max_chars -= n_chars;
 428         } else {
 429                 /* Sanity check for systems with huge ARG_MAX defines (e.g., Suns which
 430                    have it at 1 meg).  Things will work fine with a large ARG_MAX but it
 431                    will probably hurt the system more than it needs to; an array of this
 432                    size is allocated.  */
 433                 if (orig_arg_max > 20 * 1024)
 434                         orig_arg_max = 20 * 1024;
 435                 n_max_chars = orig_arg_max;
 436         }
 437         max_chars = xmalloc(n_max_chars);
 438
 439         if (opt & OPT_UPTO_NUMBER) {
 440                 n_max_arg = xatoul_range(max_args, 1, INT_MAX);
 441         } else {
 442                 n_max_arg = n_max_chars;
 443         }
 444
 445         while ((list = read_args(list, eof_str, n_max_chars, max_chars)) != NULL ||
 446                 !(opt & OPT_NO_EMPTY))
 447         {
 448                 opt |= OPT_NO_EMPTY;
 449                 n = 0;
 450                 n_chars = 0;
 451 #if ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
 452                 for (cur = list; cur;) {
 453                         n_chars += cur->length;
 454                         n++;
 455                         cur = cur->link;
 456                         if (n_chars > n_max_chars || (n == n_max_arg && cur)) {
 457                                 if (opt & OPT_TERMINATE)
 458                                         bb_error_msg_and_die("argument list too long");
 459                                 break;
 460                         }
 461                 }
 462 #else
 463                 for (cur = list; cur; cur = cur->link) {
 464                         n_chars += cur->length;
 465                         n++;
 466                         if (n_chars > n_max_chars || n == n_max_arg) {
 467                                 break;
 468                         }
 469                 }
 470 #endif /* FEATURE_XARGS_SUPPORT_TERMOPT */
 471
 472                 /* allocate pointers for execvp:
 473                    argc*arg, n*arg from stdin, NULL */
 474                 args = xzalloc((n + argc + 1) * sizeof(char *));
 475
 476                 /* store the command to be executed
 477                    (taken from the command line) */
 478                 for (i = 0; i < argc; i++)
 479                         args[i] = argv[i];
 480                 /* (taken from stdin) */
 481                 for (cur = list; n; cur = cur->link) {
 482                         args[i++] = cur->data;
 483                         n--;
 484                 }
 485
 486                 if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) {
 487                         for (i = 0; args[i]; i++) {
 488                                 if (i)
 489                                         fputc(' ', stderr);
 490                                 fputs(args[i], stderr);
 491                         }
 492                         if (!(opt & OPT_INTERACTIVE))
 493                                 fputc('\n', stderr);
 494                 }
 495                 if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) {
 496                         child_error = xargs_exec(args);
 497                 }
 498
 499                 /* clean up */
 500                 for (i = argc; args[i]; i++) {
 501                         cur = list;
 502                         list = list->link;
 503                         free(cur);
 504                 }
 505                 free(args);
 506                 if (child_error > 0 && child_error != 123) {
 507                         break;
 508                 }
 509         }
 510         if (ENABLE_FEATURE_CLEAN_UP)
 511                 free(max_chars);
 512         return child_error;
 513 }
 514
 515
 516 #ifdef TEST
 517
 518 const char *applet_name = "debug stuff usage";
 519
 520 void bb_show_usage(void)
 521 {
 522         fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
 523                 applet_name);
 524         exit(1);
 525 }
 526
 527 int main(int argc, char **argv)
 528 {
 529         return xargs_main(argc, argv);
 530 }
 531 #endif /* TEST */