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         long arg_max;
  83         int ch, Jflag, nargs, nflag, nline;
  84         size_t linelen;
  85
  86         inpline = replstr = NULL;
  87         ep = environ;
  88         eofstr = "";
  89         Jflag = nflag = 0;
  90
  91         (void)setlocale(LC_MESSAGES, "");
  92
  93         /*
  94          * POSIX.2 limits the exec line length to ARG_MAX - 2K.  Running that
  95          * caused some E2BIG errors, so it was changed to ARG_MAX - 4K.  Given
  96          * that the smallest argument is 2 bytes in length, this means that
  97          * the number of arguments is limited to:
  98          *
  99          *       (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
 100          *
 101          * We arbitrarily limit the number of arguments to 5000.  This is
 102          * allowed by POSIX.2 as long as the resulting minimum exec line is
 103          * at least LINE_MAX.  Realloc'ing as necessary is possible, but
 104          * probably not worthwhile.
 105          */
 106         nargs = 5000;
 107         if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
 108                 errx(1, "sysconf(_SC_ARG_MAX) failed");
 109         nline = arg_max - 4 * 1024;
 110         while (*ep != NULL) {
 111                 /* 1 byte for each '\0' */
 112                 nline -= strlen(*ep++) + 1 + sizeof(*ep);
 113         }
 114         while ((ch = getopt(argc, argv, "0E:I:J:L:n:opR:s:tx")) != -1)
 115                 switch(ch) {
 116                 case 'E':
 117                         eofstr = optarg;
 118                         break;
 119                 case 'I':
 120                         Jflag = 0;
 121                         Iflag = 1;
 122                         Lflag = 1;
 123                         replstr = optarg;
 124                         break;
 125                 case 'J':
 126                         Iflag = 0;
 127                         Jflag = 1;
 128                         replstr = optarg;
 129                         break;
 130                 case 'L':
 131                         Lflag = atoi(optarg);
 132                         break;
 133                 case 'n':
 134                         nflag = 1;
 135                         if ((nargs = atoi(optarg)) <= 0)
 136                                 errx(1, "illegal argument count");
 137                         break;
 138                 case 'o':
 139                         oflag = 1;
 140                         break;
 141                 case 'p':
 142                         pflag = 1;
 143                         break;
 144                 case 'R':
 145                         if ((Rflag = atoi(optarg)) <= 0)
 146                                 errx(1, "illegal number of replacements");
 147                         break;
 148                 case 's':
 149                         nline = atoi(optarg);
 150                         break;
 151                 case 't':
 152                         tflag = 1;
 153                         break;
 154                 case 'x':
 155                         xflag = 1;
 156                         break;
 157                 case '0':
 158                         zflag = 1;
 159                         break;
 160                 case '?':
 161                 default:
 162                         usage();
 163         }
 164         argc -= optind;
 165         argv += optind;
 166
 167         if (!Iflag && Rflag)
 168                 usage();
 169         if (Iflag && !Rflag)
 170                 Rflag = 5;
 171         if (xflag && !nflag)
 172                 usage();
 173         if (Iflag || Lflag)
 174                 xflag = 1;
 175         if (replstr != NULL && *replstr == '\0')
 176                 errx(1, "replstr may not be empty");
 177
 178         /*
 179          * Allocate pointers for the utility name, the utility arguments,
 180          * the maximum arguments to be read from stdin and the trailing
 181          * NULL.
 182          */
 183         linelen = 1 + argc + nargs + 1;
 184         if ((av = bxp = malloc(linelen * sizeof(char **))) == NULL)
 185                 errx(1, "malloc failed");
 186
 187         /*
 188          * Use the user's name for the utility as argv[0], just like the
 189          * shell.  Echo is the default.  Set up pointers for the user's
 190          * arguments.
 191          */
 192         if (*argv == NULL)
 193                 cnt = strlen(*bxp++ = echo);
 194         else {
 195                 do {
 196                         if (Jflag && strcmp(*argv, replstr) == 0) {
 197                                 char **avj;
 198                                 jfound = 1;
 199                                 argv++;
 200                                 for (avj = argv; *avj; avj++)
 201                                         cnt += strlen(*avj) + 1;
 202                                 break;
 203                         }
 204                         cnt += strlen(*bxp++ = *argv) + 1;
 205                 } while (*++argv != NULL);
 206         }
 207
 208         /*
 209          * Set up begin/end/traversing pointers into the array.  The -n
 210          * count doesn't include the trailing NULL pointer, so the malloc
 211          * added in an extra slot.
 212          */
 213         expx = (xp = bxp) + nargs;
 214
 215         /*
 216          * Allocate buffer space for the arguments read from stdin and the
 217          * trailing NULL.  Buffer space is defined as the default or specified
 218          * space, minus the length of the utility name and arguments.  Set up
 219          * begin/end/traversing pointers into the array.  The -s count does
 220          * include the trailing NULL, so the malloc didn't add in an extra
 221          * slot.
 222          */
 223         nline -= cnt;
 224         if (nline <= 0)
 225                 errx(1, "insufficient space for command");
 226
 227         if ((bbp = malloc((size_t)(nline + 1))) == NULL)
 228                 errx(1, "malloc failed");
 229         ebp = (argp = p = bbp) + nline - 1;
 230         for (;;)
 231                 parse_input(argc, argv);
 232 }
 233
 234 static void
 235 parse_input(int argc, char *argv[])
 236 {
 237         int ch, foundeof;
 238         char **avj;
 239
 240         foundeof = 0;
 241
 242         switch(ch = getchar()) {
 243         case EOF:
 244                 /* No arguments since last exec. */
 245                 if (p == bbp)
 246                         exit(rval);
 247                 goto arg1;
 248         case ' ':
 249         case '\t':
 250                 /* Quotes escape tabs and spaces. */
 251                 if (insingle || indouble || zflag)
 252                         goto addch;
 253                 goto arg2;
 254         case '\0':
 255                 if (zflag)
 256                         goto arg2;
 257                 goto addch;
 258         case '\n':
 259                 count++;
 260                 if (zflag)
 261                         goto addch;
 262
 263                 /* Quotes do not escape newlines. */
 264 arg1:           if (insingle || indouble)
 265                         errx(1, "unterminated quote");
 266 arg2:
 267                 foundeof = *eofstr != '\0' &&
 268                     strcmp(argp, eofstr) == 0;
 269
 270                 /* Do not make empty args unless they are quoted */
 271                 if ((argp != p || wasquoted) && !foundeof) {
 272                         *p++ = '\0';
 273                         *xp++ = argp;
 274                         if (Iflag) {
 275                                 size_t curlen;
 276
 277                                 if (inpline == NULL)
 278                                         curlen = 0;
 279                                 else {
 280                                         /*
 281                                          * If this string is not zero
 282                                          * length, append a space for
 283                                          * separation before the next
 284                                          * argument.
 285                                          */
 286                                         if ((curlen = strlen(inpline)))
 287                                                 strcat(inpline, " ");
 288                                 }
 289                                 curlen++;
 290                                 /*
 291                                  * Allocate enough to hold what we will
 292                                  * be holding in a second, and to append
 293                                  * a space next time through, if we have
 294                                  * to.
 295                                  */
 296                                 inpline = realloc(inpline, curlen + 2 +
 297                                     strlen(argp));
 298                                 if (inpline == NULL)
 299                                         errx(1, "realloc failed");
 300                                 if (curlen == 1)
 301                                         strcpy(inpline, argp);
 302                                 else
 303                                         strcat(inpline, argp);
 304                         }
 305                 }
 306
 307                 /*
 308                  * If max'd out on args or buffer, or reached EOF,
 309                  * run the command.  If xflag and max'd out on buffer
 310                  * but not on args, object.  Having reached the limit
 311                  * of input lines, as specified by -L is the same as
 312                  * maxing out on arguments.
 313                  */
 314                 if (xp == expx || p > ebp || ch == EOF ||
 315                     (Lflag <= count && xflag) || foundeof) {
 316                         if (xflag && xp != expx && p > ebp)
 317                                 errx(1, "insufficient space for arguments");
 318                         if (jfound) {
 319                                 for (avj = argv; *avj; avj++)
 320                                         *xp++ = *avj;
 321                         }
 322                         prerun(argc, av);
 323                         if (ch == EOF || foundeof)
 324                                 exit(rval);
 325                         p = bbp;
 326                         xp = bxp;
 327                         count = 0;
 328                 }
 329                 argp = p;
 330                 wasquoted = 0;
 331                 break;
 332         case '\'':
 333                 if (indouble || zflag)
 334                         goto addch;
 335                 insingle = !insingle;
 336                 wasquoted = 1;
 337                 break;
 338         case '"':
 339                 if (insingle || zflag)
 340                         goto addch;
 341                 indouble = !indouble;
 342                 wasquoted = 1;
 343                 break;
 344         case '\\':
 345                 if (zflag)
 346                         goto addch;
 347                 /* Backslash escapes anything, is escaped by quotes. */
 348                 if (!insingle && !indouble && (ch = getchar()) == EOF)
 349                         errx(1, "backslash at EOF");
 350                 /* FALLTHROUGH */
 351         default:
 352 addch:          if (p < ebp) {
 353                         *p++ = ch;
 354                         break;
 355                 }
 356
 357                 /* If only one argument, not enough buffer space. */
 358                 if (bxp == xp)
 359                         errx(1, "insufficient space for argument");
 360                 /* Didn't hit argument limit, so if xflag object. */
 361                 if (xflag)
 362                         errx(1, "insufficient space for arguments");
 363
 364                 if (jfound) {
 365                         for (avj = argv; *avj; avj++)
 366                                 *xp++ = *avj;
 367                 }
 368                 prerun(argc, av);
 369                 xp = bxp;
 370                 cnt = ebp - argp;
 371                 memcpy(bbp, argp, (size_t)cnt);
 372                 p = (argp = bbp) + cnt;
 373                 *p++ = ch;
 374                 break;
 375         }
 376         return;
 377 }
 378
 379 /*
 380  * Do things necessary before run()'ing, such as -I substitution,
 381  * and then call run().
 382  */
 383 static void
 384 prerun(int argc, char *argv[])
 385 {
 386         char **tmp, **tmp2, **avj;
 387         int repls;
 388
 389         repls = Rflag;
 390
 391         if (argc == 0 || repls == 0) {
 392                 *xp = NULL;
 393                 run(argv);
 394                 return;
 395         }
 396
 397         avj = argv;
 398
 399         /*
 400          * Allocate memory to hold the argument list, and
 401          * a NULL at the tail.
 402          */
 403         tmp = malloc((argc + 1) * sizeof(char**));
 404         if (tmp == NULL)
 405                 errx(1, "malloc failed");
 406         tmp2 = tmp;
 407
 408         /*
 409          * Save the first argument and iterate over it, we
 410          * cannot do strnsubst() to it.
 411          */
 412         if ((*tmp++ = strdup(*avj++)) == NULL)
 413                 errx(1, "strdup failed");
 414
 415         /*
 416          * For each argument to utility, if we have not used up
 417          * the number of replacements we are allowed to do, and
 418          * if the argument contains at least one occurrence of
 419          * replstr, call strnsubst(), else just save the string.
 420          * Iterations over elements of avj and tmp are done
 421          * where appropriate.
 422          */
 423         while (--argc) {
 424                 *tmp = *avj++;
 425                 if (repls && strstr(*tmp, replstr) != NULL) {
 426                         strnsubst(tmp++, replstr, inpline, (size_t)255);
 427                         repls--;
 428                 } else {
 429                         if ((*tmp = strdup(*tmp)) == NULL)
 430                                 errx(1, "strdup failed");
 431                         tmp++;
 432                 }
 433         }
 434
 435         /*
 436          * Run it.
 437          */
 438         *tmp = NULL;
 439         run(tmp2);
 440
 441         /*
 442          * Walk from the tail to the head, free along the way.
 443          */
 444         for (; tmp2 != tmp; tmp--)
 445                 free(*tmp);
 446         /*
 447          * Now free the list itself.
 448          */
 449         free(tmp2);
 450
 451         /*
 452          * Free the input line buffer, if we have one.
 453          */
 454         if (inpline != NULL) {
 455                 free(inpline);
 456                 inpline = NULL;
 457         }
 458 }
 459
 460 static void
 461 run(char **argv)
 462 {
 463         volatile int childerr;
 464         char **avec;
 465         pid_t pid;
 466         int status;
 467
 468         /*
 469          * If the user wants to be notified of each command before it is
 470          * executed, notify them.  If they want the notification to be
 471          * followed by a prompt, then prompt them.
 472          */
 473         if (tflag || pflag) {
 474                 (void)fprintf(stderr, "%s", *argv);
 475                 for (avec = argv + 1; *avec != NULL; ++avec)
 476                         (void)fprintf(stderr, " %s", *avec);
 477                 /*
 478                  * If the user has asked to be prompted, do so.
 479                  */
 480                 if (pflag)
 481                         /*
 482                          * If they asked not to exec, return without execution
 483                          * but if they asked to, go to the execution.  If we
 484                          * could not open their tty, break the switch and drop
 485                          * back to -t behaviour.
 486                          */
 487                         switch (prompt()) {
 488                         case 0:
 489                                 return;
 490                         case 1:
 491                                 goto exec;
 492                         case 2:
 493                                 break;
 494                         }
 495                 (void)fprintf(stderr, "\n");
 496                 (void)fflush(stderr);
 497         }
 498 exec:
 499         childerr = 0;
 500         switch(pid = vfork()) {
 501         case -1:
 502                 err(1, "vfork");
 503         case 0:
 504                 close(0);
 505                 if (oflag) {
 506                         if (open("/dev/tty", O_RDONLY) == -1)
 507                                 err(1, "open /dev/tty");
 508                 } else {
 509                         if (open("/dev/null", O_RDONLY) == -1)
 510                                 err(1, "open /dev/null");
 511                 }
 512                 execvp(argv[0], argv);
 513                 childerr = errno;
 514                 _exit(1);
 515         }
 516         pid = waitpid(pid, &status, 0);
 517         if (pid == -1)
 518                 err(1, "waitpid");
 519         /* If we couldn't invoke the utility, exit. */
 520         if (childerr != 0)
 521                 err(childerr == ENOENT ? 127 : 126, "%s", *argv);
 522         /* If utility signaled or exited with a value of 255, exit 1-125. */
 523         if (WIFSIGNALED(status) || WEXITSTATUS(status) == 255)
 524                 exit(1);
 525         if (WEXITSTATUS(status))
 526                 rval = 1;
 527 }
 528
 529 /*
 530  * Prompt the user about running a command.
 531  */
 532 static int
 533 prompt(void)
 534 {
 535         regex_t cre;
 536         size_t rsize;
 537         int match;
 538         char *response;
 539         FILE *ttyfp;
 540
 541         if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
 542                 return (2);     /* Indicate that the TTY failed to open. */
 543         (void)fprintf(stderr, "?...");
 544         (void)fflush(stderr);
 545         if ((response = fgetln(ttyfp, &rsize)) == NULL ||
 546             regcomp(&cre,
 547 #ifdef BOOTSTRAPPING
 548                 "^[yY]",
 549 #else
 550                 nl_langinfo(YESEXPR),
 551 #endif
 552                 REG_BASIC) != 0) {
 553                 (void)fclose(ttyfp);
 554                 return (0);
 555         }
 556         match = regexec(&cre, response, 0, NULL, 0);
 557         (void)fclose(ttyfp);
 558         regfree(&cre);
 559         return (match == 0);
 560 }
 561
 562 static void
 563 usage(void)
 564 {
 565         fprintf(stderr,
 566 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr]\n"
 567 "             [-L number] [-n number [-x] [-s size] [utility [argument ...]]\n");
 568         exit(1);
 569 }