1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * John B. Roll Jr. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * $xMach: xargs.c,v 1.6 2002/02/23 05:27:47 tim Exp $ 35 */ 36 37 #if 0 38 #ifndef lint 39 static const char copyright[] = 40 "@(#) Copyright (c) 1990, 1993\n\ 41 The Regents of the University of California. All rights reserved.\n"; 42 #endif /* not lint */ 43 44 #ifndef lint 45 static char sccsid[] = "@(#)xargs.c 8.1 (Berkeley) 6/6/93"; 46 #endif /* not lint */ 47 #endif 48 #include <sys/cdefs.h> 49 __FBSDID("$FreeBSD$"); 50 51 #include <sys/types.h> 52 #include <sys/wait.h> 53 #include <sys/time.h> 54 #include <sys/limits.h> 55 #include <sys/resource.h> 56 #include <err.h> 57 #include <errno.h> 58 #include <fcntl.h> 59 #include <langinfo.h> 60 #include <locale.h> 61 #include <paths.h> 62 #include <regex.h> 63 #include <stdio.h> 64 #include <stdlib.h> 65 #include <string.h> 66 #include <unistd.h> 67 68 #include "pathnames.h" 69 70 static void parse_input(int, char *[]); 71 static void prerun(int, char *[]); 72 static int prompt(void); 73 static void run(char **); 74 static void usage(void); 75 void strnsubst(char **, const char *, const char *, size_t); 76 static pid_t xwait(int block, int *status); 77 static void xexit(const char *, const int); 78 static void waitchildren(const char *, int); 79 static void pids_init(void); 80 static int pids_empty(void); 81 static int pids_full(void); 82 static void pids_add(pid_t pid); 83 static int pids_remove(pid_t pid); 84 static int findslot(pid_t pid); 85 static int findfreeslot(void); 86 static void clearslot(int slot); 87 88 static char echo[] = _PATH_ECHO; 89 static char **av, **bxp, **ep, **endxp, **xp; 90 static char *argp, *bbp, *ebp, *inpline, *p, *replstr; 91 static const char *eofstr; 92 static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag; 93 static int cnt, Iflag, jfound, Lflag, Sflag, wasquoted, xflag; 94 static int curprocs, maxprocs; 95 static pid_t *childpids; 96 97 static volatile int childerr; 98 99 extern char **environ; 100 101 int 102 main(int argc, char *argv[]) 103 { 104 long arg_max; 105 int ch, Jflag, nargs, nflag, nline; 106 size_t linelen; 107 struct rlimit rl; 108 char *endptr; 109 const char *errstr; 110 111 inpline = replstr = NULL; 112 ep = environ; 113 eofstr = ""; 114 Jflag = nflag = 0; 115 116 (void)setlocale(LC_ALL, ""); 117 118 /* 119 * POSIX.2 limits the exec line length to ARG_MAX - 2K. Running that 120 * caused some E2BIG errors, so it was changed to ARG_MAX - 4K. Given 121 * that the smallest argument is 2 bytes in length, this means that 122 * the number of arguments is limited to: 123 * 124 * (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2. 125 * 126 * We arbitrarily limit the number of arguments to 5000. This is 127 * allowed by POSIX.2 as long as the resulting minimum exec line is 128 * at least LINE_MAX. Realloc'ing as necessary is possible, but 129 * probably not worthwhile. 130 */ 131 nargs = 5000; 132 if ((arg_max = sysconf(_SC_ARG_MAX)) == -1) 133 errx(1, "sysconf(_SC_ARG_MAX) failed"); 134 nline = arg_max - 4 * 1024; 135 while (*ep != NULL) { 136 /* 1 byte for each '\0' */ 137 nline -= strlen(*ep++) + 1 + sizeof(*ep); 138 } 139 maxprocs = 1; 140 while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:S:s:rtx")) != -1) 141 switch (ch) { 142 case 'E': 143 eofstr = optarg; 144 break; 145 case 'I': 146 Jflag = 0; 147 Iflag = 1; 148 Lflag = 1; 149 replstr = optarg; 150 break; 151 case 'J': 152 Iflag = 0; 153 Jflag = 1; 154 replstr = optarg; 155 break; 156 case 'L': 157 Lflag = strtonum(optarg, 0, INT_MAX, &errstr); 158 if (errstr) 159 errx(1, "-L %s: %s", optarg, errstr); 160 break; 161 case 'n': 162 nflag = 1; 163 nargs = strtonum(optarg, 1, INT_MAX, &errstr); 164 if (errstr) 165 errx(1, "-n %s: %s", optarg, errstr); 166 break; 167 case 'o': 168 oflag = 1; 169 break; 170 case 'P': 171 maxprocs = strtonum(optarg, 0, INT_MAX, &errstr); 172 if (errstr) 173 errx(1, "-P %s: %s", optarg, errstr); 174 if (getrlimit(RLIMIT_NPROC, &rl) != 0) 175 errx(1, "getrlimit failed"); 176 if (maxprocs == 0 || maxprocs > rl.rlim_cur) 177 maxprocs = rl.rlim_cur; 178 break; 179 case 'p': 180 pflag = 1; 181 break; 182 case 'R': 183 Rflag = strtol(optarg, &endptr, 10); 184 if (*endptr != '\0') 185 errx(1, "replacements must be a number"); 186 break; 187 case 'r': 188 /* GNU compatibility */ 189 break; 190 case 'S': 191 Sflag = strtoul(optarg, &endptr, 10); 192 if (*endptr != '\0') 193 errx(1, "replsize must be a number"); 194 break; 195 case 's': 196 nline = strtonum(optarg, 0, INT_MAX, &errstr); 197 if (errstr) 198 errx(1, "-s %s: %s", optarg, errstr); 199 break; 200 case 't': 201 tflag = 1; 202 break; 203 case 'x': 204 xflag = 1; 205 break; 206 case '0': 207 zflag = 1; 208 break; 209 case '?': 210 default: 211 usage(); 212 } 213 argc -= optind; 214 argv += optind; 215 216 if (!Iflag && Rflag) 217 usage(); 218 if (!Iflag && Sflag) 219 usage(); 220 if (Iflag && !Rflag) 221 Rflag = 5; 222 if (Iflag && !Sflag) 223 Sflag = 255; 224 if (xflag && !nflag) 225 usage(); 226 if (Iflag || Lflag) 227 xflag = 1; 228 if (replstr != NULL && *replstr == '\0') 229 errx(1, "replstr may not be empty"); 230 231 pids_init(); 232 233 /* 234 * Allocate pointers for the utility name, the utility arguments, 235 * the maximum arguments to be read from stdin and the trailing 236 * NULL. 237 */ 238 linelen = 1 + argc + nargs + 1; 239 if ((av = bxp = malloc(linelen * sizeof(char *))) == NULL) 240 errx(1, "malloc failed"); 241 242 /* 243 * Use the user's name for the utility as argv[0], just like the 244 * shell. Echo is the default. Set up pointers for the user's 245 * arguments. 246 */ 247 if (*argv == NULL) 248 cnt = strlen(*bxp++ = echo); 249 else { 250 do { 251 if (Jflag && strcmp(*argv, replstr) == 0) { 252 char **avj; 253 jfound = 1; 254 argv++; 255 for (avj = argv; *avj; avj++) 256 cnt += strlen(*avj) + 1; 257 break; 258 } 259 cnt += strlen(*bxp++ = *argv) + 1; 260 } while (*++argv != NULL); 261 } 262 263 /* 264 * Set up begin/end/traversing pointers into the array. The -n 265 * count doesn't include the trailing NULL pointer, so the malloc 266 * added in an extra slot. 267 */ 268 endxp = (xp = bxp) + nargs; 269 270 /* 271 * Allocate buffer space for the arguments read from stdin and the 272 * trailing NULL. Buffer space is defined as the default or specified 273 * space, minus the length of the utility name and arguments. Set up 274 * begin/end/traversing pointers into the array. The -s count does 275 * include the trailing NULL, so the malloc didn't add in an extra 276 * slot. 277 */ 278 nline -= cnt; 279 if (nline <= 0) 280 errx(1, "insufficient space for command"); 281 282 if ((bbp = malloc((size_t)(nline + 1))) == NULL) 283 errx(1, "malloc failed"); 284 ebp = (argp = p = bbp) + nline - 1; 285 for (;;) 286 parse_input(argc, argv); 287 } 288 289 static void 290 parse_input(int argc, char *argv[]) 291 { 292 int ch, foundeof; 293 char **avj; 294 295 foundeof = 0; 296 297 switch (ch = getchar()) { 298 case EOF: 299 /* No arguments since last exec. */ 300 if (p == bbp) 301 xexit(*av, rval); 302 goto arg1; 303 case ' ': 304 case '\t': 305 /* Quotes escape tabs and spaces. */ 306 if (insingle || indouble || zflag) 307 goto addch; 308 goto arg2; 309 case '\0': 310 if (zflag) { 311 /* 312 * Increment 'count', so that nulls will be treated 313 * as end-of-line, as well as end-of-argument. This 314 * is needed so -0 works properly with -I and -L. 315 */ 316 count++; 317 goto arg2; 318 } 319 goto addch; 320 case '\n': 321 if (zflag) 322 goto addch; 323 count++; /* Indicate end-of-line (used by -L) */ 324 325 /* Quotes do not escape newlines. */ 326 arg1: if (insingle || indouble) { 327 warnx("unterminated quote"); 328 xexit(*av, 1); 329 } 330 arg2: 331 foundeof = *eofstr != '\0' && 332 strncmp(argp, eofstr, p - argp) == 0; 333 334 /* Do not make empty args unless they are quoted */ 335 if ((argp != p || wasquoted) && !foundeof) { 336 *p++ = '\0'; 337 *xp++ = argp; 338 if (Iflag) { 339 size_t curlen; 340 341 if (inpline == NULL) 342 curlen = 0; 343 else { 344 /* 345 * If this string is not zero 346 * length, append a space for 347 * separation before the next 348 * argument. 349 */ 350 if ((curlen = strlen(inpline))) 351 strcat(inpline, " "); 352 } 353 curlen++; 354 /* 355 * Allocate enough to hold what we will 356 * be holding in a second, and to append 357 * a space next time through, if we have 358 * to. 359 */ 360 inpline = realloc(inpline, curlen + 2 + 361 strlen(argp)); 362 if (inpline == NULL) { 363 warnx("realloc failed"); 364 xexit(*av, 1); 365 } 366 if (curlen == 1) 367 strcpy(inpline, argp); 368 else 369 strcat(inpline, argp); 370 } 371 } 372 373 /* 374 * If max'd out on args or buffer, or reached EOF, 375 * run the command. If xflag and max'd out on buffer 376 * but not on args, object. Having reached the limit 377 * of input lines, as specified by -L is the same as 378 * maxing out on arguments. 379 */ 380 if (xp == endxp || p > ebp || ch == EOF || 381 (Lflag <= count && xflag) || foundeof) { 382 if (xflag && xp != endxp && p > ebp) { 383 warnx("insufficient space for arguments"); 384 xexit(*av, 1); 385 } 386 if (jfound) { 387 for (avj = argv; *avj; avj++) 388 *xp++ = *avj; 389 } 390 prerun(argc, av); 391 if (ch == EOF || foundeof) 392 xexit(*av, rval); 393 p = bbp; 394 xp = bxp; 395 count = 0; 396 } 397 argp = p; 398 wasquoted = 0; 399 break; 400 case '\'': 401 if (indouble || zflag) 402 goto addch; 403 insingle = !insingle; 404 wasquoted = 1; 405 break; 406 case '"': 407 if (insingle || zflag) 408 goto addch; 409 indouble = !indouble; 410 wasquoted = 1; 411 break; 412 case '\\': 413 if (zflag) 414 goto addch; 415 /* Backslash escapes anything, is escaped by quotes. */ 416 if (!insingle && !indouble && (ch = getchar()) == EOF) { 417 warnx("backslash at EOF"); 418 xexit(*av, 1); 419 } 420 /* FALLTHROUGH */ 421 default: 422 addch: if (p < ebp) { 423 *p++ = ch; 424 break; 425 } 426 427 /* If only one argument, not enough buffer space. */ 428 if (bxp == xp) { 429 warnx("insufficient space for argument"); 430 xexit(*av, 1); 431 } 432 /* Didn't hit argument limit, so if xflag object. */ 433 if (xflag) { 434 warnx("insufficient space for arguments"); 435 xexit(*av, 1); 436 } 437 438 if (jfound) { 439 for (avj = argv; *avj; avj++) 440 *xp++ = *avj; 441 } 442 prerun(argc, av); 443 xp = bxp; 444 cnt = ebp - argp; 445 memcpy(bbp, argp, (size_t)cnt); 446 p = (argp = bbp) + cnt; 447 *p++ = ch; 448 break; 449 } 450 } 451 452 /* 453 * Do things necessary before run()'ing, such as -I substitution, 454 * and then call run(). 455 */ 456 static void 457 prerun(int argc, char *argv[]) 458 { 459 char **tmp, **tmp2, **avj; 460 int repls; 461 462 repls = Rflag; 463 464 if (argc == 0 || repls == 0) { 465 *xp = NULL; 466 run(argv); 467 return; 468 } 469 470 avj = argv; 471 472 /* 473 * Allocate memory to hold the argument list, and 474 * a NULL at the tail. 475 */ 476 tmp = malloc((argc + 1) * sizeof(char *)); 477 if (tmp == NULL) { 478 warnx("malloc failed"); 479 xexit(*argv, 1); 480 } 481 tmp2 = tmp; 482 483 /* 484 * Save the first argument and iterate over it, we 485 * cannot do strnsubst() to it. 486 */ 487 if ((*tmp++ = strdup(*avj++)) == NULL) { 488 warnx("strdup failed"); 489 xexit(*argv, 1); 490 } 491 492 /* 493 * For each argument to utility, if we have not used up 494 * the number of replacements we are allowed to do, and 495 * if the argument contains at least one occurrence of 496 * replstr, call strnsubst(), else just save the string. 497 * Iterations over elements of avj and tmp are done 498 * where appropriate. 499 */ 500 while (--argc) { 501 *tmp = *avj++; 502 if (repls && strstr(*tmp, replstr) != NULL) { 503 strnsubst(tmp++, replstr, inpline, (size_t)Sflag); 504 if (repls > 0) 505 repls--; 506 } else { 507 if ((*tmp = strdup(*tmp)) == NULL) { 508 warnx("strdup failed"); 509 xexit(*argv, 1); 510 } 511 tmp++; 512 } 513 } 514 515 /* 516 * Run it. 517 */ 518 *tmp = NULL; 519 run(tmp2); 520 521 /* 522 * Walk from the tail to the head, free along the way. 523 */ 524 for (; tmp2 != tmp; tmp--) 525 free(*tmp); 526 /* 527 * Now free the list itself. 528 */ 529 free(tmp2); 530 531 /* 532 * Free the input line buffer, if we have one. 533 */ 534 if (inpline != NULL) { 535 free(inpline); 536 inpline = NULL; 537 } 538 } 539 540 static void 541 run(char **argv) 542 { 543 pid_t pid; 544 int fd; 545 char **avec; 546 547 /* 548 * If the user wants to be notified of each command before it is 549 * executed, notify them. If they want the notification to be 550 * followed by a prompt, then prompt them. 551 */ 552 if (tflag || pflag) { 553 (void)fprintf(stderr, "%s", *argv); 554 for (avec = argv + 1; *avec != NULL; ++avec) 555 (void)fprintf(stderr, " %s", *avec); 556 /* 557 * If the user has asked to be prompted, do so. 558 */ 559 if (pflag) 560 /* 561 * If they asked not to exec, return without execution 562 * but if they asked to, go to the execution. If we 563 * could not open their tty, break the switch and drop 564 * back to -t behaviour. 565 */ 566 switch (prompt()) { 567 case 0: 568 return; 569 case 1: 570 goto exec; 571 case 2: 572 break; 573 } 574 (void)fprintf(stderr, "\n"); 575 (void)fflush(stderr); 576 } 577 exec: 578 childerr = 0; 579 switch (pid = vfork()) { 580 case -1: 581 warn("vfork"); 582 xexit(*argv, 1); 583 case 0: 584 if (oflag) { 585 if ((fd = open(_PATH_TTY, O_RDONLY)) == -1) 586 err(1, "can't open /dev/tty"); 587 } else { 588 fd = open(_PATH_DEVNULL, O_RDONLY); 589 } 590 if (fd > STDIN_FILENO) { 591 if (dup2(fd, STDIN_FILENO) != 0) 592 err(1, "can't dup2 to stdin"); 593 close(fd); 594 } 595 execvp(argv[0], argv); 596 childerr = errno; 597 _exit(1); 598 } 599 pids_add(pid); 600 waitchildren(*argv, 0); 601 } 602 603 /* 604 * Wait for a tracked child to exit and return its pid and exit status. 605 * 606 * Ignores (discards) all untracked child processes. 607 * Returns -1 and sets errno to ECHILD if no tracked children exist. 608 * If block is set, waits indefinitely for a child process to exit. 609 * If block is not set and no children have exited, returns 0 immediately. 610 */ 611 static pid_t 612 xwait(int block, int *status) { 613 pid_t pid; 614 615 if (pids_empty()) { 616 errno = ECHILD; 617 return (-1); 618 } 619 620 while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0) 621 if (pids_remove(pid)) 622 break; 623 624 return (pid); 625 } 626 627 static void 628 xexit(const char *name, const int exit_code) { 629 waitchildren(name, 1); 630 exit(exit_code); 631 } 632 633 static void 634 waitchildren(const char *name, int waitall) 635 { 636 pid_t pid; 637 int status; 638 int cause_exit = 0; 639 640 while ((pid = xwait(waitall || pids_full(), &status)) > 0) { 641 /* 642 * If we couldn't invoke the utility or if utility exited 643 * because of a signal or with a value of 255, warn (per 644 * POSIX), and then wait until all other children have 645 * exited before exiting 1-125. POSIX requires us to stop 646 * reading if child exits because of a signal or with 255, 647 * but it does not require us to exit immediately; waiting 648 * is preferable to orphaning. 649 */ 650 if (childerr != 0 && cause_exit == 0) { 651 errno = childerr; 652 waitall = 1; 653 cause_exit = errno == ENOENT ? 127 : 126; 654 warn("%s", name); 655 } else if (WIFSIGNALED(status)) { 656 waitall = cause_exit = 1; 657 warnx("%s: terminated with signal %d; aborting", 658 name, WTERMSIG(status)); 659 } else if (WEXITSTATUS(status) == 255) { 660 waitall = cause_exit = 1; 661 warnx("%s: exited with status 255; aborting", name); 662 } else if (WEXITSTATUS(status)) 663 rval = 1; 664 } 665 666 if (cause_exit) 667 exit(cause_exit); 668 if (pid == -1 && errno != ECHILD) 669 err(1, "waitpid"); 670 } 671 672 #define NOPID (0) 673 674 static void 675 pids_init(void) 676 { 677 int i; 678 679 if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL) 680 errx(1, "malloc failed"); 681 682 for (i = 0; i < maxprocs; i++) 683 clearslot(i); 684 } 685 686 static int 687 pids_empty(void) 688 { 689 690 return (curprocs == 0); 691 } 692 693 static int 694 pids_full(void) 695 { 696 697 return (curprocs >= maxprocs); 698 } 699 700 static void 701 pids_add(pid_t pid) 702 { 703 int slot; 704 705 slot = findfreeslot(); 706 childpids[slot] = pid; 707 curprocs++; 708 } 709 710 static int 711 pids_remove(pid_t pid) 712 { 713 int slot; 714 715 if ((slot = findslot(pid)) < 0) 716 return (0); 717 718 clearslot(slot); 719 curprocs--; 720 return (1); 721 } 722 723 static int 724 findfreeslot(void) 725 { 726 int slot; 727 728 if ((slot = findslot(NOPID)) < 0) 729 errx(1, "internal error: no free pid slot"); 730 return (slot); 731 } 732 733 static int 734 findslot(pid_t pid) 735 { 736 int slot; 737 738 for (slot = 0; slot < maxprocs; slot++) 739 if (childpids[slot] == pid) 740 return (slot); 741 return (-1); 742 } 743 744 static void 745 clearslot(int slot) 746 { 747 748 childpids[slot] = NOPID; 749 } 750 751 /* 752 * Prompt the user about running a command. 753 */ 754 static int 755 prompt(void) 756 { 757 regex_t cre; 758 size_t rsize; 759 int match; 760 char *response; 761 FILE *ttyfp; 762 763 if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL) 764 return (2); /* Indicate that the TTY failed to open. */ 765 (void)fprintf(stderr, "?..."); 766 (void)fflush(stderr); 767 if ((response = fgetln(ttyfp, &rsize)) == NULL || 768 regcomp(&cre, nl_langinfo(YESEXPR), REG_BASIC) != 0) { 769 (void)fclose(ttyfp); 770 return (0); 771 } 772 response[rsize - 1] = '\0'; 773 match = regexec(&cre, response, 0, NULL, 0); 774 (void)fclose(ttyfp); 775 regfree(&cre); 776 return (match == 0); 777 } 778 779 static void 780 usage(void) 781 { 782 783 fprintf(stderr, 784 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n" 785 " [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n" 786 " [-s size] [utility [argument ...]]\n"); 787 exit(1); 788 } 789