usr.bin/xargs/xargs.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * John B. Roll Jr.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * $xMach: xargs.c,v 1.6 2002/02/23 05:27:47 tim Exp $
  37  *
  38  * @(#) Copyright (c) 1990, 1993 The Regents of the University of California.  All rights reserved.
  39  * @(#)xargs.c  8.1 (Berkeley) 6/6/93
  40  * $FreeBSD: src/usr.bin/xargs/xargs.c,v 1.9.2.6 2003/06/01 21:40:35 mux Exp $
  41  * $DragonFly: src/usr.bin/xargs/xargs.c,v 1.3 2004/07/27 21:42:48 dillon Exp $
  42  */
  43
  44 #include <sys/types.h>
  45 #include <sys/wait.h>
  46
  47 #include <err.h>
  48 #include <errno.h>
  49 #include <fcntl.h>
  50 #ifndef BOOTSTRAPPING
  51 #include <langinfo.h>
  52 #endif
  53 #include <locale.h>
  54 #include <paths.h>
  55 #include <regex.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59 #include <unistd.h>
  60
  61 #include "pathnames.h"
  62
  63 static void     parse_input(int, char *[]);
  64 static void     prerun(int, char *[]);
  65 static int      prompt(void);
  66 static void     run(char **);
  67 static void     usage(void);
  68 void            strnsubst(char **, const char *, const char *, size_t);
  69
  70 static char echo[] = _PATH_ECHO;
  71 static char **av, **bxp, **ep, **expx, **xp;
  72 static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
  73 static const char *eofstr;
  74 static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
  75 static int cnt, Iflag, jfound, Lflag, wasquoted, xflag;
  76
  77 extern char **environ;
  78
  79 int
  80 main(int argc, char *argv[])
  81 {
  82         char *tmp;
  83         long arg_max;
  84         int ch, Jflag, nargs, nflag, nline;
  85         size_t linelen;
  86
  87         inpline = replstr = NULL;
  88         ep = environ;
  89         eofstr = "";
  90         Jflag = nflag = 0;
  91
  92         (void)setlocale(LC_MESSAGES, "");
  93
  94         /*
  95          * POSIX.2 limits the exec line length to ARG_MAX - 2K.  Running that
  96          * caused some E2BIG errors, so it was changed to ARG_MAX - 4K.  Given
  97          * that the smallest argument is 2 bytes in length, this means that
  98          * the number of arguments is limited to:
  99          *
 100          *       (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
 101          *
 102          * We arbitrarily limit the number of arguments to 5000.  This is
 103          * allowed by POSIX.2 as long as the resulting minimum exec line is
 104          * at least LINE_MAX.  Realloc'ing as necessary is possible, but
 105          * probably not worthwhile.
 106          */
 107         nargs = 5000;
 108         if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
 109                 errx(1, "sysconf(_SC_ARG_MAX) failed");
 110         nline = arg_max - 4 * 1024;
 111         while (*ep != NULL) {
 112                 /* 1 byte for each '\0' */
 113                 nline -= strlen(*ep++) + 1 + sizeof(*ep);
 114         }
 115         while ((ch = getopt(argc, argv, "0E:I:J:L:n:opR:s:tx")) != -1)
 116                 switch(ch) {
 117                 case 'E':
 118                         eofstr = optarg;
 119                         break;
 120                 case 'I':
 121                         Jflag = 0;
 122                         Iflag = 1;
 123                         Lflag = 1;
 124                         replstr = optarg;
 125                         break;
 126                 case 'J':
 127                         Iflag = 0;
 128                         Jflag = 1;
 129                         replstr = optarg;
 130                         break;
 131                 case 'L':
 132                         Lflag = strtol(optarg, &tmp, 10);
 133                         if (*tmp != 0 || *optarg == 0)
 134                                 errx(1, "illegal argument count");
 135                         break;
 136                 case 'n':
 137                         nflag = 1;
 138                         if ((nargs = atoi(optarg)) <= 0)
 139                                 errx(1, "illegal argument count");
 140                         break;
 141                 case 'o':
 142                         oflag = 1;
 143                         break;
 144                 case 'p':
 145                         pflag = 1;
 146                         break;
 147                 case 'R':
 148                         if ((Rflag = atoi(optarg)) <= 0)
 149                                 errx(1, "illegal number of replacements");
 150                         break;
 151                 case 's':
 152                         nline = atoi(optarg);
 153                         break;
 154                 case 't':
 155                         tflag = 1;
 156                         break;
 157                 case 'x':
 158                         xflag = 1;
 159                         break;
 160                 case '0':
 161                         zflag = 1;
 162                         break;
 163                 case '?':
 164                 default:
 165                         usage();
 166         }
 167         argc -= optind;
 168         argv += optind;
 169
 170         if (!Iflag && Rflag)
 171                 usage();
 172         if (Iflag && !Rflag)
 173                 Rflag = 5;
 174         if (xflag && !nflag)
 175                 usage();
 176         if (Iflag || Lflag)
 177                 xflag = 1;
 178         if (replstr != NULL && *replstr == '\0')
 179                 errx(1, "replstr may not be empty");
 180
 181         /*
 182          * Allocate pointers for the utility name, the utility arguments,
 183          * the maximum arguments to be read from stdin and the trailing
 184          * NULL.
 185          */
 186         linelen = 1 + argc + nargs + 1;
 187         if ((av = bxp = malloc(linelen * sizeof(char **))) == NULL)
 188                 errx(1, "malloc failed");
 189
 190         /*
 191          * Use the user's name for the utility as argv[0], just like the
 192          * shell.  Echo is the default.  Set up pointers for the user's
 193          * arguments.
 194          */
 195         if (*argv == NULL)
 196                 cnt = strlen(*bxp++ = echo);
 197         else {
 198                 do {
 199                         if (Jflag && strcmp(*argv, replstr) == 0) {
 200                                 char **avj;
 201                                 jfound = 1;
 202                                 argv++;
 203                                 for (avj = argv; *avj; avj++)
 204                                         cnt += strlen(*avj) + 1;
 205                                 break;
 206                         }
 207                         cnt += strlen(*bxp++ = *argv) + 1;
 208                 } while (*++argv != NULL);
 209         }
 210
 211         /*
 212          * Set up begin/end/traversing pointers into the array.  The -n
 213          * count doesn't include the trailing NULL pointer, so the malloc
 214          * added in an extra slot.
 215          */
 216         expx = (xp = bxp) + nargs;
 217
 218         /*
 219          * Allocate buffer space for the arguments read from stdin and the
 220          * trailing NULL.  Buffer space is defined as the default or specified
 221          * space, minus the length of the utility name and arguments.  Set up
 222          * begin/end/traversing pointers into the array.  The -s count does
 223          * include the trailing NULL, so the malloc didn't add in an extra
 224          * slot.
 225          */
 226         nline -= cnt;
 227         if (nline <= 0)
 228                 errx(1, "insufficient space for command");
 229
 230         if ((bbp = malloc((size_t)(nline + 1))) == NULL)
 231                 errx(1, "malloc failed");
 232         ebp = (argp = p = bbp) + nline - 1;
 233         for (;;)
 234                 parse_input(argc, argv);
 235 }
 236
 237 static void
 238 parse_input(int argc, char *argv[])
 239 {
 240         int ch, foundeof;
 241         char **avj;
 242
 243         foundeof = 0;
 244
 245         switch(ch = getchar()) {
 246         case EOF:
 247                 /* No arguments since last exec. */
 248                 if (p == bbp)
 249                         exit(rval);
 250                 goto arg1;
 251         case ' ':
 252         case '\t':
 253                 /* Quotes escape tabs and spaces. */
 254                 if (insingle || indouble || zflag)
 255                         goto addch;
 256                 goto arg2;
 257         case '\0':
 258                 if (zflag)
 259                         goto arg2;
 260                 goto addch;
 261         case '\n':
 262                 count++;
 263                 if (zflag)
 264                         goto addch;
 265
 266                 /* Quotes do not escape newlines. */
 267 arg1:           if (insingle || indouble)
 268                         errx(1, "unterminated quote");
 269 arg2:
 270                 foundeof = *eofstr != '\0' &&
 271                     strcmp(argp, eofstr) == 0;
 272
 273                 /* Do not make empty args unless they are quoted */
 274                 if ((argp != p || wasquoted) && !foundeof) {
 275                         *p++ = '\0';
 276                         *xp++ = argp;
 277                         if (Iflag) {
 278                                 size_t curlen;
 279
 280                                 if (inpline == NULL)
 281                                         curlen = 0;
 282                                 else {
 283                                         /*
 284                                          * If this string is not zero
 285                                          * length, append a space for
 286                                          * separation before the next
 287                                          * argument.
 288                                          */
 289                                         if ((curlen = strlen(inpline)))
 290                                                 strcat(inpline, " ");
 291                                 }
 292                                 curlen++;
 293                                 /*
 294                                  * Allocate enough to hold what we will
 295                                  * be holding in a second, and to append
 296                                  * a space next time through, if we have
 297                                  * to.
 298                                  */
 299                                 inpline = realloc(inpline, curlen + 2 +
 300                                     strlen(argp));
 301                                 if (inpline == NULL)
 302                                         errx(1, "realloc failed");
 303                                 if (curlen == 1)
 304                                         strcpy(inpline, argp);
 305                                 else
 306                                         strcat(inpline, argp);
 307                         }
 308                 }
 309
 310                 /*
 311                  * If max'd out on args or buffer, or reached EOF,
 312                  * run the command.  If xflag and max'd out on buffer
 313                  * but not on args, object.  Having reached the limit
 314                  * of input lines, as specified by -L is the same as
 315                  * maxing out on arguments.
 316                  */
 317                 if (xp == expx || p > ebp || ch == EOF ||
 318                     (Lflag <= count && xflag) || foundeof) {
 319                         if (xflag && xp != expx && p > ebp)
 320                                 errx(1, "insufficient space for arguments");
 321                         if (jfound) {
 322                                 for (avj = argv; *avj; avj++)
 323                                         *xp++ = *avj;
 324                         }
 325                         prerun(argc, av);
 326                         if (ch == EOF || foundeof)
 327                                 exit(rval);
 328                         p = bbp;
 329                         xp = bxp;
 330                         count = 0;
 331                 }
 332                 argp = p;
 333                 wasquoted = 0;
 334                 break;
 335         case '\'':
 336                 if (indouble || zflag)
 337                         goto addch;
 338                 insingle = !insingle;
 339                 wasquoted = 1;
 340                 break;
 341         case '"':
 342                 if (insingle || zflag)
 343                         goto addch;
 344                 indouble = !indouble;
 345                 wasquoted = 1;
 346                 break;
 347         case '\\':
 348                 if (zflag)
 349                         goto addch;
 350                 /* Backslash escapes anything, is escaped by quotes. */
 351                 if (!insingle && !indouble && (ch = getchar()) == EOF)
 352                         errx(1, "backslash at EOF");
 353                 /* FALLTHROUGH */
 354         default:
 355 addch:          if (p < ebp) {
 356                         *p++ = ch;
 357                         break;
 358                 }
 359
 360                 /* If only one argument, not enough buffer space. */
 361                 if (bxp == xp)
 362                         errx(1, "insufficient space for argument");
 363                 /* Didn't hit argument limit, so if xflag object. */
 364                 if (xflag)
 365                         errx(1, "insufficient space for arguments");
 366
 367                 if (jfound) {
 368                         for (avj = argv; *avj; avj++)
 369                                 *xp++ = *avj;
 370                 }
 371                 prerun(argc, av);
 372                 xp = bxp;
 373                 cnt = ebp - argp;
 374                 memcpy(bbp, argp, (size_t)cnt);
 375                 p = (argp = bbp) + cnt;
 376                 *p++ = ch;
 377                 break;
 378         }
 379         return;
 380 }
 381
 382 /*
 383  * Do things necessary before run()'ing, such as -I substitution,
 384  * and then call run().
 385  */
 386 static void
 387 prerun(int argc, char *argv[])
 388 {
 389         char **tmp, **tmp2, **avj;
 390         int repls;
 391
 392         repls = Rflag;
 393
 394         if (argc == 0 || repls == 0) {
 395                 *xp = NULL;
 396                 run(argv);
 397                 return;
 398         }
 399
 400         avj = argv;
 401
 402         /*
 403          * Allocate memory to hold the argument list, and
 404          * a NULL at the tail.
 405          */
 406         tmp = malloc((argc + 1) * sizeof(char**));
 407         if (tmp == NULL)
 408                 errx(1, "malloc failed");
 409         tmp2 = tmp;
 410
 411         /*
 412          * Save the first argument and iterate over it, we
 413          * cannot do strnsubst() to it.
 414          */
 415         if ((*tmp++ = strdup(*avj++)) == NULL)
 416                 errx(1, "strdup failed");
 417
 418         /*
 419          * For each argument to utility, if we have not used up
 420          * the number of replacements we are allowed to do, and
 421          * if the argument contains at least one occurrence of
 422          * replstr, call strnsubst(), else just save the string.
 423          * Iterations over elements of avj and tmp are done
 424          * where appropriate.
 425          */
 426         while (--argc) {
 427                 *tmp = *avj++;
 428                 if (repls && strstr(*tmp, replstr) != NULL) {
 429                         strnsubst(tmp++, replstr, inpline, (size_t)255);
 430                         repls--;
 431                 } else {
 432                         if ((*tmp = strdup(*tmp)) == NULL)
 433                                 errx(1, "strdup failed");
 434                         tmp++;
 435                 }
 436         }
 437
 438         /*
 439          * Run it.
 440          */
 441         *tmp = NULL;
 442         run(tmp2);
 443
 444         /*
 445          * Walk from the tail to the head, free along the way.
 446          */
 447         for (; tmp2 != tmp; tmp--)
 448                 free(*tmp);
 449         /*
 450          * Now free the list itself.
 451          */
 452         free(tmp2);
 453
 454         /*
 455          * Free the input line buffer, if we have one.
 456          */
 457         if (inpline != NULL) {
 458                 free(inpline);
 459                 inpline = NULL;
 460         }
 461 }
 462
 463 static void
 464 run(char **argv)
 465 {
 466         volatile int childerr;
 467         char **avec;
 468         pid_t pid;
 469         int status;
 470
 471         /*
 472          * If the user wants to be notified of each command before it is
 473          * executed, notify them.  If they want the notification to be
 474          * followed by a prompt, then prompt them.
 475          */
 476         if (tflag || pflag) {
 477                 (void)fprintf(stderr, "%s", *argv);
 478                 for (avec = argv + 1; *avec != NULL; ++avec)
 479                         (void)fprintf(stderr, " %s", *avec);
 480                 /*
 481                  * If the user has asked to be prompted, do so.
 482                  */
 483                 if (pflag)
 484                         /*
 485                          * If they asked not to exec, return without execution
 486                          * but if they asked to, go to the execution.  If we
 487                          * could not open their tty, break the switch and drop
 488                          * back to -t behaviour.
 489                          */
 490                         switch (prompt()) {
 491                         case 0:
 492                                 return;
 493                         case 1:
 494                                 goto exec;
 495                         case 2:
 496                                 break;
 497                         }
 498                 (void)fprintf(stderr, "\n");
 499                 (void)fflush(stderr);
 500         }
 501 exec:
 502         childerr = 0;
 503         switch(pid = vfork()) {
 504         case -1:
 505                 err(1, "vfork");
 506         case 0:
 507                 close(0);
 508                 if (oflag) {
 509                         if (open("/dev/tty", O_RDONLY) == -1)
 510                                 err(1, "open /dev/tty");
 511                 } else {
 512                         if (open("/dev/null", O_RDONLY) == -1)
 513                                 err(1, "open /dev/null");
 514                 }
 515                 execvp(argv[0], argv);
 516                 childerr = errno;
 517                 _exit(1);
 518         }
 519         pid = waitpid(pid, &status, 0);
 520         if (pid == -1)
 521                 err(1, "waitpid");
 522         /* If we couldn't invoke the utility, exit. */
 523         if (childerr != 0)
 524                 err(childerr == ENOENT ? 127 : 126, "%s", *argv);
 525         /* If utility signaled or exited with a value of 255, exit 1-125. */
 526         if (WIFSIGNALED(status) || WEXITSTATUS(status) == 255)
 527                 exit(1);
 528         if (WEXITSTATUS(status))
 529                 rval = 1;
 530 }
 531
 532 /*
 533  * Prompt the user about running a command.
 534  */
 535 static int
 536 prompt(void)
 537 {
 538         regex_t cre;
 539         size_t rsize;
 540         int match;
 541         char *response;
 542         FILE *ttyfp;
 543
 544         if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
 545                 return (2);     /* Indicate that the TTY failed to open. */
 546         (void)fprintf(stderr, "?...");
 547         (void)fflush(stderr);
 548         if ((response = fgetln(ttyfp, &rsize)) == NULL ||
 549             regcomp(&cre,
 550 #ifdef BOOTSTRAPPING
 551                 "^[yY]",
 552 #else
 553                 nl_langinfo(YESEXPR),
 554 #endif
 555                 REG_BASIC) != 0) {
 556                 (void)fclose(ttyfp);
 557                 return (0);
 558         }
 559         match = regexec(&cre, response, 0, NULL, 0);
 560         (void)fclose(ttyfp);
 561         regfree(&cre);
 562         return (match == 0);
 563 }
 564
 565 static void
 566 usage(void)
 567 {
 568         fprintf(stderr,
 569 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr]\n"
 570 "             [-L number] [-n number [-x] [-s size] [utility [argument ...]]\n");
 571         exit(1);
 572 }