shell_cmds/xargs/xargs.c

   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/param.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 #ifdef __APPLE__
  71 #include <get_compat.h>
  72 #else
  73 #define COMPAT_MODE(a,b) (1)
  74 #endif /* __APPLE__ */
  75
  76 static void     parse_input(int, char *[]);
  77 static void     prerun(int, char *[]);
  78 static int      prompt(void);
  79 static void     run(char **);
  80 static void     usage(void);
  81 void            strnsubst(char **, const char *, const char *, size_t);
  82 static pid_t  xwait(int block, int *status);
  83 static void   xexit(const char *, const int);
  84 static void     waitchildren(const char *, int);
  85 static void   pids_init(void);
  86 static int    pids_empty(void);
  87 static int    pids_full(void);
  88 static void   pids_add(pid_t pid);
  89 static int    pids_remove(pid_t pid);
  90 static int    findslot(pid_t pid);
  91 static int    findfreeslot(void);
  92 static void   clearslot(int slot);
  93
  94 static int last_was_newline = 1;
  95 static int last_was_blank = 0;
  96
  97 static char echo[] = _PATH_ECHO;
  98 static char **av, **bxp, **ep, **endxp, **xp;
  99 static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
 100 static const char *eofstr;
 101 static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
 102 static int cnt, Iflag, jfound, Lflag, Sflag, wasquoted, xflag;
 103 static int curprocs, maxprocs;
 104 static size_t pad9314053;
 105 static pid_t *childpids;
 106
 107 static volatile int childerr;
 108
 109 extern char **environ;
 110
 111 int
 112 main(int argc, char *argv[])
 113 {
 114         long arg_max;
 115         int ch, Jflag, nflag, nline;
 116         size_t nargs;
 117         size_t linelen;
 118         struct rlimit rl;
 119         char *endptr;
 120         const char *errstr;
 121
 122         inpline = replstr = NULL;
 123         ep = environ;
 124         eofstr = "";
 125         Jflag = nflag = 0;
 126
 127         (void)setlocale(LC_ALL, "");
 128
 129         /*
 130          * POSIX.2 limits the exec line length to ARG_MAX - 2K.  Running that
 131          * caused some E2BIG errors, so it was changed to ARG_MAX - 4K.  Given
 132          * that the smallest argument is 2 bytes in length, this means that
 133          * the number of arguments is limited to:
 134          *
 135          *       (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
 136          *
 137          * We arbitrarily limit the number of arguments to 5000.  This is
 138          * allowed by POSIX.2 as long as the resulting minimum exec line is
 139          * at least LINE_MAX.  Realloc'ing as necessary is possible, but
 140          * probably not worthwhile.
 141          */
 142         nargs = 5000;
 143         if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
 144                 errx(1, "sysconf(_SC_ARG_MAX) failed");
 145         nline = arg_max - MAXPATHLEN; /* for argv[0] from execvp() */
 146         pad9314053 = sizeof(char *); /* reserve for string area rounding */
 147         while (*ep != NULL) {
 148                 /* 1 byte for each '\0' */
 149                 nline -= strlen(*ep++) + 1 + sizeof(*ep);
 150         }
 151         nline -= pad9314053;
 152         maxprocs = 1;
 153         while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:S:s:rtx")) != -1)
 154                 switch (ch) {
 155                 case 'E':
 156                         eofstr = optarg;
 157                         break;
 158                 case 'I':
 159                         Jflag = 0;
 160                         Iflag = 1;
 161                         Lflag = 1;
 162                         replstr = optarg;
 163                         break;
 164                 case 'J':
 165                         Iflag = 0;
 166                         Jflag = 1;
 167                         replstr = optarg;
 168                         break;
 169                 case 'L':
 170                         Lflag = strtonum(optarg, 0, INT_MAX, &errstr);
 171                         if (errstr)
 172                                 errx(1, "-L %s: %s", optarg, errstr);
 173                         if (COMPAT_MODE("bin/xargs", "Unix2003")) {
 174                                 nflag = 0; /* Override */
 175                                 nargs = 5000;
 176                         }
 177                         break;
 178                 case 'n':
 179                         nflag = 1;
 180                         if ((nargs = strtol(optarg, NULL, 10)) <= 0)
 181                                 errx(1, "illegal argument count");
 182                         if (COMPAT_MODE("bin/xargs", "Unix2003")) {
 183                                 Lflag = 0; /* Override */
 184                         }
 185                         break;
 186                 case 'o':
 187                         oflag = 1;
 188                         break;
 189                 case 'P':
 190                         maxprocs = strtonum(optarg, 0, INT_MAX, &errstr);
 191                         if (errstr)
 192                                 errx(1, "-P %s: %s", optarg, errstr);
 193                         if (getrlimit(RLIMIT_NPROC, &rl) != 0)
 194                                 errx(1, "getrlimit failed");
 195                         if (maxprocs == 0 || maxprocs > rl.rlim_cur)
 196                                 maxprocs = rl.rlim_cur;
 197                         break;
 198                 case 'p':
 199                         pflag = 1;
 200                         break;
 201                 case 'R':
 202                         Rflag = strtol(optarg, &endptr, 10);
 203                         if (*endptr != '\0')
 204                                 errx(1, "replacements must be a number");
 205                         break;
 206                 case 'r':
 207                         /* GNU compatibility */
 208                         break;
 209                 case 'S':
 210                         Sflag = strtoul(optarg, &endptr, 10);
 211                         if (*endptr != '\0')
 212                                 errx(1, "replsize must be a number");
 213                         break;
 214                 case 's':
 215                         nline = strtonum(optarg, 0, INT_MAX, &errstr);
 216                         if (errstr)
 217                                 errx(1, "-s %s: %s", optarg, errstr);
 218                         pad9314053 = 0; /* assume the -s value is valid */
 219                         break;
 220                 case 't':
 221                         tflag = 1;
 222                         break;
 223                 case 'x':
 224                         xflag = 1;
 225                         break;
 226                 case '0':
 227                         zflag = 1;
 228                         break;
 229                 case '?':
 230                 default:
 231                         usage();
 232         }
 233         argc -= optind;
 234         argv += optind;
 235
 236         if (!Iflag && Rflag)
 237                 usage();
 238         if (!Iflag && Sflag)
 239                 usage();
 240         if (Iflag && !Rflag)
 241                 Rflag = 5;
 242         if (Iflag && !Sflag)
 243                 Sflag = 255;
 244         if (xflag && !nflag)
 245                 usage();
 246         if (Iflag || Lflag)
 247                 xflag = 1;
 248         if (replstr != NULL && *replstr == '\0')
 249                 errx(1, "replstr may not be empty");
 250
 251         pids_init();
 252
 253         /*
 254          * Allocate pointers for the utility name, the utility arguments,
 255          * the maximum arguments to be read from stdin and the trailing
 256          * NULL.
 257          */
 258         linelen = 1 + argc + nargs + 1;
 259         if ((av = bxp = malloc(linelen * sizeof(char *))) == NULL)
 260                 errx(1, "malloc failed");
 261
 262         /*
 263          * Use the user's name for the utility as argv[0], just like the
 264          * shell.  Echo is the default.  Set up pointers for the user's
 265          * arguments.
 266          */
 267         if (*argv == NULL)
 268                 cnt = strlen(*bxp++ = echo) + pad9314053;
 269         else {
 270                 do {
 271                         if (Jflag && strcmp(*argv, replstr) == 0) {
 272                                 char **avj;
 273                                 jfound = 1;
 274                                 argv++;
 275                                 for (avj = argv; *avj; avj++)
 276                                         cnt += strlen(*avj) + 1 + pad9314053;
 277                                 break;
 278                         }
 279                         cnt += strlen(*bxp++ = *argv) + 1 + pad9314053;
 280                 } while (*++argv != NULL);
 281         }
 282
 283         /*
 284          * Set up begin/end/traversing pointers into the array.  The -n
 285          * count doesn't include the trailing NULL pointer, so the malloc
 286          * added in an extra slot.
 287          */
 288         endxp = (xp = bxp) + nargs;
 289
 290         /*
 291          * Allocate buffer space for the arguments read from stdin and the
 292          * trailing NULL.  Buffer space is defined as the default or specified
 293          * space, minus the length of the utility name and arguments.  Set up
 294          * begin/end/traversing pointers into the array.  The -s count does
 295          * include the trailing NULL, so the malloc didn't add in an extra
 296          * slot.
 297          */
 298         nline -= cnt;
 299         if (nline <= 0)
 300                 errx(1, "insufficient space for command");
 301
 302         if ((bbp = malloc((size_t)(nline + 1))) == NULL)
 303                 errx(1, "malloc failed");
 304         ebp = (argp = p = bbp) + nline - 1;
 305         for (;;)
 306                 parse_input(argc, argv);
 307 }
 308
 309 static void
 310 parse_input(int argc, char *argv[])
 311 {
 312         int ch, foundeof;
 313         char **avj;
 314         int last_was_backslashed = 0;
 315
 316         foundeof = 0;
 317
 318         switch (ch = getchar()) {
 319         case EOF:
 320                 /* No arguments since last exec. */
 321                 if (p == bbp)
 322                         xexit(*av, rval);
 323                 goto arg1;
 324         case ' ':
 325                 last_was_blank = 1;
 326         case '\t':
 327                 /* Quotes escape tabs and spaces. */
 328                 if (insingle || indouble || zflag)
 329                         goto addch;
 330                 goto arg2;
 331         case '\0':
 332                 if (zflag) {
 333                         /*
 334                          * Increment 'count', so that nulls will be treated
 335                          * as end-of-line, as well as end-of-argument.  This
 336                          * is needed so -0 works properly with -I and -L.
 337                          */
 338                         count++;
 339                         goto arg2;
 340                 }
 341                 goto addch;
 342         case '\n':
 343                 if (zflag)
 344                         goto addch;
 345                 if (COMPAT_MODE("bin/xargs", "Unix2003")) {
 346                         if (last_was_newline) {
 347                                 /* don't count empty line */
 348                                 break;
 349                         }
 350                         if (!last_was_blank ) {
 351                                 /* only count if NOT continuation line */
 352                                 count++;
 353                         }
 354                 } else {
 355                         count++;
 356                 }
 357                 last_was_newline = 1;
 358
 359                 /* Quotes do not escape newlines. */
 360 arg1:           if (insingle || indouble) {
 361                         warnx("unterminated quote");
 362                         xexit(*av, 1);
 363                 }
 364 arg2:
 365                 foundeof = *eofstr != '\0' &&
 366                     strncmp(argp, eofstr, p - argp) == 0;
 367
 368 #ifdef __APPLE__
 369                 /* 6591323: -I specifies that it processes the entire line,
 370                  * so only recognize eofstr at the end of a line. */
 371                 if (Iflag && !last_was_newline)
 372                         foundeof = 0;
 373
 374                 /* 6591323: Essentially the same as the EOF handling above. */
 375                 if (foundeof && (p - strlen(eofstr) == bbp)) {
 376                         waitchildren(*argv, 1);
 377                         exit(rval);
 378                 }
 379 #endif
 380
 381                 /* Do not make empty args unless they are quoted */
 382                 if ((argp != p || wasquoted) && !foundeof) {
 383                         *p++ = '\0';
 384                         *xp++ = argp;
 385                         if (Iflag) {
 386                                 size_t curlen;
 387
 388                                 if (inpline == NULL)
 389                                         curlen = 0;
 390                                 else {
 391                                         /*
 392                                          * If this string is not zero
 393                                          * length, append a space for
 394                                          * separation before the next
 395                                          * argument.
 396                                          */
 397                                         if ((curlen = strlen(inpline)))
 398                                                 strcat(inpline, " ");
 399                                 }
 400                                 curlen++;
 401                                 /*
 402                                  * Allocate enough to hold what we will
 403                                  * be holding in a second, and to append
 404                                  * a space next time through, if we have
 405                                  * to.
 406                                  */
 407                                 inpline = realloc(inpline, curlen + 2 +
 408                                     strlen(argp));
 409                                 if (inpline == NULL) {
 410                                         warnx("realloc failed");
 411                                         xexit(*av, 1);
 412                                 }
 413                                 if (curlen == 1)
 414                                         strcpy(inpline, argp);
 415                                 else
 416                                         strcat(inpline, argp);
 417                         }
 418                 }
 419
 420                 /*
 421                  * If max'd out on args or buffer, or reached EOF,
 422                  * run the command.  If xflag and max'd out on buffer
 423                  * but not on args, object.  Having reached the limit
 424                  * of input lines, as specified by -L is the same as
 425                  * maxing out on arguments.
 426                  */
 427                 if (xp == endxp || p + (count * pad9314053) > ebp || ch == EOF ||
 428                     (Lflag <= count && xflag) || foundeof) {
 429                         if (xflag && xp != endxp && p + (count * pad9314053) > ebp) {
 430                                 warnx("insufficient space for arguments");
 431                                 xexit(*av, 1);
 432                         }
 433                         if (jfound) {
 434                                 for (avj = argv; *avj; avj++)
 435                                         *xp++ = *avj;
 436                         }
 437                         prerun(argc, av);
 438                         if (ch == EOF || foundeof)
 439                                 xexit(*av, rval);
 440                         p = bbp;
 441                         xp = bxp;
 442                         count = 0;
 443                 }
 444                 argp = p;
 445                 wasquoted = 0;
 446                 break;
 447         case '\'':
 448                 if (indouble || zflag)
 449                         goto addch;
 450                 insingle = !insingle;
 451                 wasquoted = 1;
 452                 break;
 453         case '"':
 454                 if (insingle || zflag)
 455                         goto addch;
 456                 indouble = !indouble;
 457                 wasquoted = 1;
 458                 break;
 459         case '\\':
 460                 last_was_backslashed = 1;
 461                 if (zflag)
 462                         goto addch;
 463                 /* Backslash escapes anything, is escaped by quotes. */
 464                 if (!insingle && !indouble && (ch = getchar()) == EOF) {
 465                         warnx("backslash at EOF");
 466                         xexit(*av, 1);
 467                 }
 468                 /* FALLTHROUGH */
 469         default:
 470 addch:          if (p < ebp) {
 471                         *p++ = ch;
 472                         break;
 473                 }
 474
 475                 /* If only one argument, not enough buffer space. */
 476                 if (bxp == xp) {
 477                         warnx("insufficient space for argument");
 478                         xexit(*av, 1);
 479                 }
 480                 /* Didn't hit argument limit, so if xflag object. */
 481                 if (xflag) {
 482                         warnx("insufficient space for arguments");
 483                         xexit(*av, 1);
 484                 }
 485
 486                 if (jfound) {
 487                         for (avj = argv; *avj; avj++)
 488                                 *xp++ = *avj;
 489                 }
 490                 prerun(argc, av);
 491                 xp = bxp;
 492                 cnt = ebp - argp;
 493                 memcpy(bbp, argp, (size_t)cnt);
 494                 p = (argp = bbp) + cnt;
 495                 *p++ = ch;
 496                 break;
 497         }
 498         if (ch != ' ')
 499                 last_was_blank = 0;
 500         if (ch != '\n' || last_was_backslashed)
 501                 last_was_newline = 0;
 502 }
 503
 504 /*
 505  * Do things necessary before run()'ing, such as -I substitution,
 506  * and then call run().
 507  */
 508 static void
 509 prerun(int argc, char *argv[])
 510 {
 511         char **tmp, **tmp2, **avj;
 512         int repls;
 513
 514         repls = Rflag;
 515
 516         if (argc == 0 || repls == 0) {
 517                 *xp = NULL;
 518                 run(argv);
 519                 return;
 520         }
 521
 522         avj = argv;
 523
 524         /*
 525          * Allocate memory to hold the argument list, and
 526          * a NULL at the tail.
 527          */
 528         tmp = malloc((argc + 1) * sizeof(char *));
 529         if (tmp == NULL) {
 530                 warnx("malloc failed");
 531                 xexit(*argv, 1);
 532         }
 533         tmp2 = tmp;
 534
 535         /*
 536          * Save the first argument and iterate over it, we
 537          * cannot do strnsubst() to it.
 538          */
 539         if ((*tmp++ = strdup(*avj++)) == NULL) {
 540                 warnx("strdup failed");
 541                 xexit(*argv, 1);
 542         }
 543
 544         /*
 545          * For each argument to utility, if we have not used up
 546          * the number of replacements we are allowed to do, and
 547          * if the argument contains at least one occurrence of
 548          * replstr, call strnsubst(), else just save the string.
 549          * Iterations over elements of avj and tmp are done
 550          * where appropriate.
 551          */
 552         while (--argc) {
 553                 *tmp = *avj++;
 554                 if (repls && strstr(*tmp, replstr) != NULL) {
 555                         strnsubst(tmp++, replstr, inpline, (size_t)Sflag);
 556                         if (repls > 0)
 557                                 repls--;
 558                 } else {
 559                         if ((*tmp = strdup(*tmp)) == NULL) {
 560                                 warnx("strdup failed");
 561                                 xexit(*argv, 1);
 562                         }
 563                         tmp++;
 564                 }
 565         }
 566
 567         /*
 568          * Run it.
 569          */
 570         *tmp = NULL;
 571         run(tmp2);
 572
 573         /*
 574          * Walk from the tail to the head, free along the way.
 575          */
 576         for (; tmp2 != tmp; tmp--)
 577                 free(*tmp);
 578         /*
 579          * Now free the list itself.
 580          */
 581         free(tmp2);
 582
 583         /*
 584          * Free the input line buffer, if we have one.
 585          */
 586         if (inpline != NULL) {
 587                 free(inpline);
 588                 inpline = NULL;
 589         }
 590 }
 591
 592 static void
 593 run(char **argv)
 594 {
 595         pid_t pid;
 596         int fd;
 597         char **avec;
 598
 599         /*
 600          * If the user wants to be notified of each command before it is
 601          * executed, notify them.  If they want the notification to be
 602          * followed by a prompt, then prompt them.
 603          */
 604         if (tflag || pflag) {
 605                 (void)fprintf(stderr, "%s", *argv);
 606                 for (avec = argv + 1; *avec != NULL; ++avec)
 607                         (void)fprintf(stderr, " %s", *avec);
 608                 /*
 609                  * If the user has asked to be prompted, do so.
 610                  */
 611                 if (pflag)
 612                         /*
 613                          * If they asked not to exec, return without execution
 614                          * but if they asked to, go to the execution.  If we
 615                          * could not open their tty, break the switch and drop
 616                          * back to -t behaviour.
 617                          */
 618                         switch (prompt()) {
 619                         case 0:
 620                                 return;
 621                         case 1:
 622                                 goto exec;
 623                         case 2:
 624                                 break;
 625                         }
 626                 (void)fprintf(stderr, "\n");
 627                 (void)fflush(stderr);
 628         }
 629 exec:
 630         childerr = 0;
 631         switch (pid = vfork()) {
 632         case -1:
 633                 warn("vfork");
 634                 xexit(*argv, 1);
 635         case 0:
 636                 if (oflag) {
 637                         if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
 638                                 err(1, "can't open /dev/tty");
 639                 } else {
 640                         fd = open(_PATH_DEVNULL, O_RDONLY);
 641                 }
 642                 if (fd > STDIN_FILENO) {
 643                         if (dup2(fd, STDIN_FILENO) != 0)
 644                                 err(1, "can't dup2 to stdin");
 645                         close(fd);
 646                 }
 647                 execvp(argv[0], argv);
 648                 childerr = errno;
 649                 _exit(1);
 650         }
 651         pids_add(pid);
 652         waitchildren(*argv, 0);
 653 }
 654
 655 /*
 656  * Wait for a tracked child to exit and return its pid and exit status.
 657  *
 658  * Ignores (discards) all untracked child processes.
 659  * Returns -1 and sets errno to ECHILD if no tracked children exist.
 660  * If block is set, waits indefinitely for a child process to exit.
 661  * If block is not set and no children have exited, returns 0 immediately.
 662  */
 663 static pid_t
 664 xwait(int block, int *status) {
 665         pid_t pid;
 666
 667         if (pids_empty()) {
 668                 errno = ECHILD;
 669                 return (-1);
 670         }
 671
 672         while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0)
 673                 if (pids_remove(pid))
 674                         break;
 675
 676         return (pid);
 677 }
 678
 679 static void
 680 xexit(const char *name, const int exit_code) {
 681         waitchildren(name, 1);
 682         exit(exit_code);
 683 }
 684
 685 static void
 686 waitchildren(const char *name, int waitall)
 687 {
 688         pid_t pid;
 689         int status;
 690         int cause_exit = 0;
 691
 692         while ((pid = xwait(waitall || pids_full(), &status)) > 0) {
 693                 /*
 694                  * If we couldn't invoke the utility or if utility exited
 695                  * because of a signal or with a value of 255, warn (per
 696                  * POSIX), and then wait until all other children have
 697                  * exited before exiting 1-125. POSIX requires us to stop
 698                  * reading if child exits because of a signal or with 255,
 699                  * but it does not require us to exit immediately; waiting
 700                  * is preferable to orphaning.
 701                  */
 702                 if (childerr != 0 && cause_exit == 0) {
 703                         errno = childerr;
 704                         waitall = 1;
 705                         cause_exit = errno == ENOENT ? 127 : 126;
 706                         warn("%s", name);
 707                 } else if (WIFSIGNALED(status)) {
 708                         waitall = cause_exit = 1;
 709                         warnx("%s: terminated with signal %d; aborting",
 710                             name, WTERMSIG(status));
 711                 } else if (WEXITSTATUS(status) == 255) {
 712                         waitall = cause_exit = 1;
 713                         warnx("%s: exited with status 255; aborting", name);
 714                 } else if (WEXITSTATUS(status))
 715                         rval = 1;
 716         }
 717
 718         if (cause_exit)
 719                 exit(cause_exit);
 720         if (pid == -1 && errno != ECHILD)
 721                 err(1, "waitpid");
 722 }
 723
 724 #define NOPID   (0)
 725
 726 static void
 727 pids_init(void)
 728 {
 729         int i;
 730
 731         if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL)
 732                 errx(1, "malloc failed");
 733
 734         for (i = 0; i < maxprocs; i++)
 735                 clearslot(i);
 736 }
 737
 738 static int
 739 pids_empty(void)
 740 {
 741
 742         return (curprocs == 0);
 743 }
 744
 745 static int
 746 pids_full(void)
 747 {
 748
 749         return (curprocs >= maxprocs);
 750 }
 751
 752 static void
 753 pids_add(pid_t pid)
 754 {
 755         int slot;
 756
 757         slot = findfreeslot();
 758         childpids[slot] = pid;
 759         curprocs++;
 760 }
 761
 762 static int
 763 pids_remove(pid_t pid)
 764 {
 765         int slot;
 766
 767         if ((slot = findslot(pid)) < 0)
 768                 return (0);
 769
 770         clearslot(slot);
 771         curprocs--;
 772         return (1);
 773 }
 774
 775 static int
 776 findfreeslot(void)
 777 {
 778         int slot;
 779
 780         if ((slot = findslot(NOPID)) < 0)
 781                 errx(1, "internal error: no free pid slot");
 782         return (slot);
 783 }
 784
 785 static int
 786 findslot(pid_t pid)
 787 {
 788         int slot;
 789
 790         for (slot = 0; slot < maxprocs; slot++)
 791                 if (childpids[slot] == pid)
 792                         return (slot);
 793         return (-1);
 794 }
 795
 796 static void
 797 clearslot(int slot)
 798 {
 799
 800         childpids[slot] = NOPID;
 801 }
 802
 803 /*
 804  * Prompt the user about running a command.
 805  */
 806 static int
 807 prompt(void)
 808 {
 809         regex_t cre;
 810         size_t rsize;
 811         int match;
 812         char *response;
 813         FILE *ttyfp;
 814
 815         if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
 816                 return (2);     /* Indicate that the TTY failed to open. */
 817         (void)fprintf(stderr, "?...");
 818         (void)fflush(stderr);
 819         if ((response = fgetln(ttyfp, &rsize)) == NULL ||
 820             regcomp(&cre, nl_langinfo(YESEXPR), REG_BASIC) != 0) {
 821                 (void)fclose(ttyfp);
 822                 return (0);
 823         }
 824         response[rsize - 1] = '\0';
 825         match = regexec(&cre, response, 0, NULL, 0);
 826         (void)fclose(ttyfp);
 827         regfree(&cre);
 828         return (match == 0);
 829 }
 830
 831 static void
 832 usage(void)
 833 {
 834
 835         fprintf(stderr,
 836 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n"
 837 "             [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n"
 838 "             [-s size] [utility [argument ...]]\n");
 839         exit(1);
 840 }