misc.c

   1 /* Miscellaneous generic support functions for GNU Make.
   2 Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
   3 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software
   4 Foundation, Inc.
   5 This file is part of GNU Make.
   6
   7 GNU Make is free software; you can redistribute it and/or modify it under the
   8 terms of the GNU General Public License as published by the Free Software
   9 Foundation; either version 2, or (at your option) any later version.
  10
  11 GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  13 A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License along with
  16 GNU Make; see the file COPYING.  If not, write to the Free Software
  17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.  */
  18
  19 #include "make.h"
  20 #include "dep.h"
  21 #include "debug.h"
  22
  23 /* Variadic functions.  We go through contortions to allow proper function
  24    prototypes for both ANSI and pre-ANSI C compilers, and also for those
  25    which support stdarg.h vs. varargs.h, and finally those which have
  26    vfprintf(), etc. and those who have _doprnt... or nothing.
  27
  28    This fancy stuff all came from GNU fileutils, except for the VA_PRINTF and
  29    VA_END macros used here since we have multiple print functions.  */
  30
  31 #if USE_VARIADIC
  32 # if HAVE_STDARG_H
  33 #  include <stdarg.h>
  34 #  define VA_START(args, lastarg) va_start(args, lastarg)
  35 # else
  36 #  include <varargs.h>
  37 #  define VA_START(args, lastarg) va_start(args)
  38 # endif
  39 # if HAVE_VPRINTF
  40 #  define VA_PRINTF(fp, lastarg, args) vfprintf((fp), (lastarg), (args))
  41 # else
  42 #  define VA_PRINTF(fp, lastarg, args) _doprnt((lastarg), (args), (fp))
  43 # endif
  44 # define VA_END(args) va_end(args)
  45 #else
  46 /* We can't use any variadic interface! */
  47 # define va_alist a1, a2, a3, a4, a5, a6, a7, a8
  48 # define va_dcl char *a1, *a2, *a3, *a4, *a5, *a6, *a7, *a8;
  49 # define VA_START(args, lastarg)
  50 # define VA_PRINTF(fp, lastarg, args) fprintf((fp), (lastarg), va_alist)
  51 # define VA_END(args)
  52 #endif
  53
  54
  55 /* Compare strings *S1 and *S2.
  56    Return negative if the first is less, positive if it is greater,
  57    zero if they are equal.  */
  58
  59 int
  60 alpha_compare (const void *v1, const void *v2)
  61 {
  62   const char *s1 = *((char **)v1);
  63   const char *s2 = *((char **)v2);
  64
  65   if (*s1 != *s2)
  66     return *s1 - *s2;
  67   return strcmp (s1, s2);
  68 }
  69 \f
  70 /* Discard each backslash-newline combination from LINE.
  71    Backslash-backslash-newline combinations become backslash-newlines.
  72    This is done by copying the text at LINE into itself.  */
  73
  74 void
  75 collapse_continuations (char *line)
  76 {
  77   register char *in, *out, *p;
  78   register int backslash;
  79   register unsigned int bs_write;
  80
  81   in = strchr (line, '\n');
  82   if (in == 0)
  83     return;
  84
  85   out = in;
  86   while (out > line && out[-1] == '\\')
  87     --out;
  88
  89   while (*in != '\0')
  90     {
  91       /* BS_WRITE gets the number of quoted backslashes at
  92          the end just before IN, and BACKSLASH gets nonzero
  93          if the next character is quoted.  */
  94       backslash = 0;
  95       bs_write = 0;
  96       for (p = in - 1; p >= line && *p == '\\'; --p)
  97         {
  98           if (backslash)
  99             ++bs_write;
 100           backslash = !backslash;
 101
 102           /* It should be impossible to go back this far without exiting,
 103              but if we do, we can't get the right answer.  */
 104           if (in == out - 1)
 105             abort ();
 106         }
 107
 108       /* Output the appropriate number of backslashes.  */
 109       while (bs_write-- > 0)
 110         *out++ = '\\';
 111
 112       /* Skip the newline.  */
 113       ++in;
 114
 115       /* If the newline is quoted, discard following whitespace
 116          and any preceding whitespace; leave just one space.  */
 117       if (backslash)
 118         {
 119           in = next_token (in);
 120           while (out > line && isblank ((unsigned char)out[-1]))
 121             --out;
 122           *out++ = ' ';
 123         }
 124       else
 125         /* If the newline isn't quoted, put it in the output.  */
 126         *out++ = '\n';
 127
 128       /* Now copy the following line to the output.
 129          Stop when we find backslashes followed by a newline.  */
 130       while (*in != '\0')
 131         if (*in == '\\')
 132           {
 133             p = in + 1;
 134             while (*p == '\\')
 135               ++p;
 136             if (*p == '\n')
 137               {
 138                 in = p;
 139                 break;
 140               }
 141             while (in < p)
 142               *out++ = *in++;
 143           }
 144         else
 145           *out++ = *in++;
 146     }
 147
 148   *out = '\0';
 149 }
 150 \f
 151 /* Print N spaces (used in debug for target-depth).  */
 152
 153 void
 154 print_spaces (unsigned int n)
 155 {
 156   while (n-- > 0)
 157     putchar (' ');
 158 }
 159
 160 \f
 161 /* Return a string whose contents concatenate those of s1, s2, s3.
 162    This string lives in static, re-used memory.  */
 163
 164 char *
 165 concat (const char *s1, const char *s2, const char *s3)
 166 {
 167   unsigned int len1, len2, len3;
 168   static unsigned int rlen = 0;
 169   static char *result = NULL;
 170
 171   len1 = (s1 && *s1 != '\0') ? strlen (s1) : 0;
 172   len2 = (s2 && *s2 != '\0') ? strlen (s2) : 0;
 173   len3 = (s3 && *s3 != '\0') ? strlen (s3) : 0;
 174
 175   if (len1 + len2 + len3 + 1 > rlen)
 176     result = xrealloc (result, (rlen = len1 + len2 + len3 + 10));
 177
 178   if (len1)
 179     memcpy (result, s1, len1);
 180   if (len2)
 181     memcpy (result + len1, s2, len2);
 182   if (len3)
 183     memcpy (result + len1 + len2, s3, len3);
 184
 185   result[len1+len2+len3] = '\0';
 186
 187   return result;
 188 }
 189 \f
 190 /* Print a message on stdout.  */
 191
 192 void
 193 #if HAVE_ANSI_COMPILER && USE_VARIADIC && HAVE_STDARG_H
 194 message (int prefix, const char *fmt, ...)
 195 #else
 196 message (prefix, fmt, va_alist)
 197      int prefix;
 198      const char *fmt;
 199      va_dcl
 200 #endif
 201 {
 202 #if USE_VARIADIC
 203   va_list args;
 204 #endif
 205
 206   log_working_directory (1);
 207
 208   if (fmt != 0)
 209     {
 210       if (prefix)
 211         {
 212           if (makelevel == 0)
 213             printf ("%s: ", program);
 214           else
 215             printf ("%s[%u]: ", program, makelevel);
 216         }
 217       VA_START (args, fmt);
 218       VA_PRINTF (stdout, fmt, args);
 219       VA_END (args);
 220       putchar ('\n');
 221     }
 222
 223   fflush (stdout);
 224 }
 225
 226 /* Print an error message.  */
 227
 228 void
 229 #if HAVE_ANSI_COMPILER && USE_VARIADIC && HAVE_STDARG_H
 230 error (const struct floc *flocp, const char *fmt, ...)
 231 #else
 232 error (flocp, fmt, va_alist)
 233      const struct floc *flocp;
 234      const char *fmt;
 235      va_dcl
 236 #endif
 237 {
 238 #if USE_VARIADIC
 239   va_list args;
 240 #endif
 241
 242   log_working_directory (1);
 243
 244   if (flocp && flocp->filenm)
 245     fprintf (stderr, "%s:%lu: ", flocp->filenm, flocp->lineno);
 246   else if (makelevel == 0)
 247     fprintf (stderr, "%s: ", program);
 248   else
 249     fprintf (stderr, "%s[%u]: ", program, makelevel);
 250
 251   VA_START(args, fmt);
 252   VA_PRINTF (stderr, fmt, args);
 253   VA_END (args);
 254
 255   putc ('\n', stderr);
 256   fflush (stderr);
 257 }
 258
 259 /* Print an error message and exit.  */
 260
 261 void
 262 #if HAVE_ANSI_COMPILER && USE_VARIADIC && HAVE_STDARG_H
 263 fatal (const struct floc *flocp, const char *fmt, ...)
 264 #else
 265 fatal (flocp, fmt, va_alist)
 266      const struct floc *flocp;
 267      const char *fmt;
 268      va_dcl
 269 #endif
 270 {
 271 #if USE_VARIADIC
 272   va_list args;
 273 #endif
 274
 275   log_working_directory (1);
 276
 277   if (flocp && flocp->filenm)
 278     fprintf (stderr, "%s:%lu: *** ", flocp->filenm, flocp->lineno);
 279   else if (makelevel == 0)
 280     fprintf (stderr, "%s: *** ", program);
 281   else
 282     fprintf (stderr, "%s[%u]: *** ", program, makelevel);
 283
 284   VA_START(args, fmt);
 285   VA_PRINTF (stderr, fmt, args);
 286   VA_END (args);
 287
 288   fputs (_(".  Stop.\n"), stderr);
 289
 290   die (2);
 291 }
 292
 293 #ifndef HAVE_STRERROR
 294
 295 #undef  strerror
 296
 297 char *
 298 strerror (int errnum)
 299 {
 300   extern int errno, sys_nerr;
 301 #ifndef __DECC
 302   extern char *sys_errlist[];
 303 #endif
 304   static char buf[] = "Unknown error 12345678901234567890";
 305
 306   if (errno < sys_nerr)
 307     return sys_errlist[errnum];
 308
 309   sprintf (buf, _("Unknown error %d"), errnum);
 310   return buf;
 311 }
 312 #endif
 313
 314 /* Print an error message from errno.  */
 315
 316 void
 317 perror_with_name (const char *str, const char *name)
 318 {
 319   error (NILF, _("%s%s: %s"), str, name, strerror (errno));
 320 }
 321
 322 /* Print an error message from errno and exit.  */
 323
 324 void
 325 pfatal_with_name (const char *name)
 326 {
 327   fatal (NILF, _("%s: %s"), name, strerror (errno));
 328
 329   /* NOTREACHED */
 330 }
 331 \f
 332 /* Like malloc but get fatal error if memory is exhausted.  */
 333 /* Don't bother if we're using dmalloc; it provides these for us.  */
 334
 335 #ifndef HAVE_DMALLOC_H
 336
 337 #undef xmalloc
 338 #undef xrealloc
 339 #undef xstrdup
 340
 341 void *
 342 xmalloc (unsigned int size)
 343 {
 344   /* Make sure we don't allocate 0, for pre-ANSI libraries.  */
 345   void *result = malloc (size ? size : 1);
 346   if (result == 0)
 347     fatal (NILF, _("virtual memory exhausted"));
 348   return result;
 349 }
 350
 351
 352 void *
 353 xrealloc (void *ptr, unsigned int size)
 354 {
 355   void *result;
 356
 357   /* Some older implementations of realloc() don't conform to ANSI.  */
 358   if (! size)
 359     size = 1;
 360   result = ptr ? realloc (ptr, size) : malloc (size);
 361   if (result == 0)
 362     fatal (NILF, _("virtual memory exhausted"));
 363   return result;
 364 }
 365
 366
 367 char *
 368 xstrdup (const char *ptr)
 369 {
 370   char *result;
 371
 372 #ifdef HAVE_STRDUP
 373   result = strdup (ptr);
 374 #else
 375   result = malloc (strlen (ptr) + 1);
 376 #endif
 377
 378   if (result == 0)
 379     fatal (NILF, _("virtual memory exhausted"));
 380
 381 #ifdef HAVE_STRDUP
 382   return result;
 383 #else
 384   return strcpy (result, ptr);
 385 #endif
 386 }
 387
 388 #endif  /* HAVE_DMALLOC_H */
 389
 390 char *
 391 savestring (const char *str, unsigned int length)
 392 {
 393   char *out = xmalloc (length + 1);
 394   if (length > 0)
 395     memcpy (out, str, length);
 396   out[length] = '\0';
 397   return out;
 398 }
 399 \f
 400
 401 /* Limited INDEX:
 402    Search through the string STRING, which ends at LIMIT, for the character C.
 403    Returns a pointer to the first occurrence, or nil if none is found.
 404    Like INDEX except that the string searched ends where specified
 405    instead of at the first null.  */
 406
 407 char *
 408 lindex (const char *s, const char *limit, int c)
 409 {
 410   while (s < limit)
 411     if (*s++ == c)
 412       return (char *)(s - 1);
 413
 414   return 0;
 415 }
 416 \f
 417 /* Return the address of the first whitespace or null in the string S.  */
 418
 419 char *
 420 end_of_token (const char *s)
 421 {
 422   while (*s != '\0' && !isblank ((unsigned char)*s))
 423     ++s;
 424   return (char *)s;
 425 }
 426
 427 #ifdef WINDOWS32
 428 /*
 429  * Same as end_of_token, but take into account a stop character
 430  */
 431 char *
 432 end_of_token_w32 (const char *s, char stopchar)
 433 {
 434   const char *p = s;
 435   int backslash = 0;
 436
 437   while (*p != '\0' && *p != stopchar
 438          && (backslash || !isblank ((unsigned char)*p)))
 439     {
 440       if (*p++ == '\\')
 441         {
 442           backslash = !backslash;
 443           while (*p == '\\')
 444             {
 445               backslash = !backslash;
 446               ++p;
 447             }
 448         }
 449       else
 450         backslash = 0;
 451     }
 452
 453   return (char *)p;
 454 }
 455 #endif
 456
 457 /* Return the address of the first nonwhitespace or null in the string S.  */
 458
 459 char *
 460 next_token (const char *s)
 461 {
 462   while (isblank ((unsigned char)*s))
 463     ++s;
 464   return (char *)s;
 465 }
 466
 467 /* Find the next token in PTR; return the address of it, and store the length
 468    of the token into *LENGTHPTR if LENGTHPTR is not nil.  Set *PTR to the end
 469    of the token, so this function can be called repeatedly in a loop.  */
 470
 471 char *
 472 find_next_token (const char **ptr, unsigned int *lengthptr)
 473 {
 474   const char *p = next_token (*ptr);
 475
 476   if (*p == '\0')
 477     return 0;
 478
 479   *ptr = end_of_token (p);
 480   if (lengthptr != 0)
 481     *lengthptr = *ptr - p;
 482
 483   return (char *)p;
 484 }
 485 \f
 486
 487 /* Allocate a new `struct dep' with all fields initialized to 0.   */
 488
 489 struct dep *
 490 alloc_dep ()
 491 {
 492   struct dep *d = xmalloc (sizeof (struct dep));
 493   memset (d, '\0', sizeof (struct dep));
 494   return d;
 495 }
 496
 497
 498 /* Free `struct dep' along with `name' and `stem'.   */
 499
 500 void
 501 free_dep (struct dep *d)
 502 {
 503   free (d);
 504 }
 505
 506 /* Copy a chain of `struct dep', making a new chain
 507    with the same contents as the old one.  */
 508
 509 struct dep *
 510 copy_dep_chain (const struct dep *d)
 511 {
 512   struct dep *firstnew = 0;
 513   struct dep *lastnew = 0;
 514
 515   while (d != 0)
 516     {
 517       struct dep *c = xmalloc (sizeof (struct dep));
 518       memcpy (c, d, sizeof (struct dep));
 519
 520       c->next = 0;
 521       if (firstnew == 0)
 522         firstnew = lastnew = c;
 523       else
 524         lastnew = lastnew->next = c;
 525
 526       d = d->next;
 527     }
 528
 529   return firstnew;
 530 }
 531
 532 /* Free a chain of 'struct dep'.  */
 533
 534 void
 535 free_dep_chain (struct dep *d)
 536 {
 537   while (d != 0)
 538     {
 539       struct dep *df = d;
 540       d = d->next;
 541       free_dep (df);
 542     }
 543 }
 544
 545 /* Free a chain of struct nameseq.
 546    For struct dep chains use free_dep_chain.  */
 547
 548 void
 549 free_ns_chain (struct nameseq *ns)
 550 {
 551   while (ns != 0)
 552     {
 553       struct nameseq *t = ns;
 554       ns = ns->next;
 555       free (t);
 556     }
 557 }
 558 \f
 559 #ifdef  GETLOADAVG_PRIVILEGED
 560
 561 #ifdef POSIX
 562
 563 /* Hopefully if a system says it's POSIX.1 and has the setuid and setgid
 564    functions, they work as POSIX.1 says.  Some systems (Alpha OSF/1 1.2,
 565    for example) which claim to be POSIX.1 also have the BSD setreuid and
 566    setregid functions, but they don't work as in BSD and only the POSIX.1
 567    way works.  */
 568
 569 #undef HAVE_SETREUID
 570 #undef HAVE_SETREGID
 571
 572 #else   /* Not POSIX.  */
 573
 574 /* Some POSIX.1 systems have the seteuid and setegid functions.  In a
 575    POSIX-like system, they are the best thing to use.  However, some
 576    non-POSIX systems have them too but they do not work in the POSIX style
 577    and we must use setreuid and setregid instead.  */
 578
 579 #undef HAVE_SETEUID
 580 #undef HAVE_SETEGID
 581
 582 #endif  /* POSIX.  */
 583
 584 #ifndef HAVE_UNISTD_H
 585 extern int getuid (), getgid (), geteuid (), getegid ();
 586 extern int setuid (), setgid ();
 587 #ifdef HAVE_SETEUID
 588 extern int seteuid ();
 589 #else
 590 #ifdef  HAVE_SETREUID
 591 extern int setreuid ();
 592 #endif  /* Have setreuid.  */
 593 #endif  /* Have seteuid.  */
 594 #ifdef HAVE_SETEGID
 595 extern int setegid ();
 596 #else
 597 #ifdef  HAVE_SETREGID
 598 extern int setregid ();
 599 #endif  /* Have setregid.  */
 600 #endif  /* Have setegid.  */
 601 #endif  /* No <unistd.h>.  */
 602
 603 /* Keep track of the user and group IDs for user- and make- access.  */
 604 static int user_uid = -1, user_gid = -1, make_uid = -1, make_gid = -1;
 605 #define access_inited   (user_uid != -1)
 606 static enum { make, user } current_access;
 607
 608
 609 /* Under -d, write a message describing the current IDs.  */
 610
 611 static void
 612 log_access (const char *flavor)
 613 {
 614   if (! ISDB (DB_JOBS))
 615     return;
 616
 617   /* All the other debugging messages go to stdout,
 618      but we write this one to stderr because it might be
 619      run in a child fork whose stdout is piped.  */
 620
 621   fprintf (stderr, _("%s: user %lu (real %lu), group %lu (real %lu)\n"),
 622            flavor, (unsigned long) geteuid (), (unsigned long) getuid (),
 623            (unsigned long) getegid (), (unsigned long) getgid ());
 624   fflush (stderr);
 625 }
 626
 627
 628 static void
 629 init_access (void)
 630 {
 631 #ifndef VMS
 632   user_uid = getuid ();
 633   user_gid = getgid ();
 634
 635   make_uid = geteuid ();
 636   make_gid = getegid ();
 637
 638   /* Do these ever fail?  */
 639   if (user_uid == -1 || user_gid == -1 || make_uid == -1 || make_gid == -1)
 640     pfatal_with_name ("get{e}[gu]id");
 641
 642   log_access (_("Initialized access"));
 643
 644   current_access = make;
 645 #endif
 646 }
 647
 648 #endif  /* GETLOADAVG_PRIVILEGED */
 649
 650 /* Give the process appropriate permissions for access to
 651    user data (i.e., to stat files, or to spawn a child process).  */
 652 void
 653 user_access (void)
 654 {
 655 #ifdef  GETLOADAVG_PRIVILEGED
 656
 657   if (!access_inited)
 658     init_access ();
 659
 660   if (current_access == user)
 661     return;
 662
 663   /* We are in "make access" mode.  This means that the effective user and
 664      group IDs are those of make (if it was installed setuid or setgid).
 665      We now want to set the effective user and group IDs to the real IDs,
 666      which are the IDs of the process that exec'd make.  */
 667
 668 #ifdef  HAVE_SETEUID
 669
 670   /* Modern systems have the seteuid/setegid calls which set only the
 671      effective IDs, which is ideal.  */
 672
 673   if (seteuid (user_uid) < 0)
 674     pfatal_with_name ("user_access: seteuid");
 675
 676 #else   /* Not HAVE_SETEUID.  */
 677
 678 #ifndef HAVE_SETREUID
 679
 680   /* System V has only the setuid/setgid calls to set user/group IDs.
 681      There is an effective ID, which can be set by setuid/setgid.
 682      It can be set (unless you are root) only to either what it already is
 683      (returned by geteuid/getegid, now in make_uid/make_gid),
 684      the real ID (return by getuid/getgid, now in user_uid/user_gid),
 685      or the saved set ID (what the effective ID was before this set-ID
 686      executable (make) was exec'd).  */
 687
 688   if (setuid (user_uid) < 0)
 689     pfatal_with_name ("user_access: setuid");
 690
 691 #else   /* HAVE_SETREUID.  */
 692
 693   /* In 4BSD, the setreuid/setregid calls set both the real and effective IDs.
 694      They may be set to themselves or each other.  So you have two alternatives
 695      at any one time.  If you use setuid/setgid, the effective will be set to
 696      the real, leaving only one alternative.  Using setreuid/setregid, however,
 697      you can toggle between your two alternatives by swapping the values in a
 698      single setreuid or setregid call.  */
 699
 700   if (setreuid (make_uid, user_uid) < 0)
 701     pfatal_with_name ("user_access: setreuid");
 702
 703 #endif  /* Not HAVE_SETREUID.  */
 704 #endif  /* HAVE_SETEUID.  */
 705
 706 #ifdef  HAVE_SETEGID
 707   if (setegid (user_gid) < 0)
 708     pfatal_with_name ("user_access: setegid");
 709 #else
 710 #ifndef HAVE_SETREGID
 711   if (setgid (user_gid) < 0)
 712     pfatal_with_name ("user_access: setgid");
 713 #else
 714   if (setregid (make_gid, user_gid) < 0)
 715     pfatal_with_name ("user_access: setregid");
 716 #endif
 717 #endif
 718
 719   current_access = user;
 720
 721   log_access (_("User access"));
 722
 723 #endif  /* GETLOADAVG_PRIVILEGED */
 724 }
 725
 726 /* Give the process appropriate permissions for access to
 727    make data (i.e., the load average).  */
 728 void
 729 make_access (void)
 730 {
 731 #ifdef  GETLOADAVG_PRIVILEGED
 732
 733   if (!access_inited)
 734     init_access ();
 735
 736   if (current_access == make)
 737     return;
 738
 739   /* See comments in user_access, above.  */
 740
 741 #ifdef  HAVE_SETEUID
 742   if (seteuid (make_uid) < 0)
 743     pfatal_with_name ("make_access: seteuid");
 744 #else
 745 #ifndef HAVE_SETREUID
 746   if (setuid (make_uid) < 0)
 747     pfatal_with_name ("make_access: setuid");
 748 #else
 749   if (setreuid (user_uid, make_uid) < 0)
 750     pfatal_with_name ("make_access: setreuid");
 751 #endif
 752 #endif
 753
 754 #ifdef  HAVE_SETEGID
 755   if (setegid (make_gid) < 0)
 756     pfatal_with_name ("make_access: setegid");
 757 #else
 758 #ifndef HAVE_SETREGID
 759   if (setgid (make_gid) < 0)
 760     pfatal_with_name ("make_access: setgid");
 761 #else
 762   if (setregid (user_gid, make_gid) < 0)
 763     pfatal_with_name ("make_access: setregid");
 764 #endif
 765 #endif
 766
 767   current_access = make;
 768
 769   log_access (_("Make access"));
 770
 771 #endif  /* GETLOADAVG_PRIVILEGED */
 772 }
 773
 774 /* Give the process appropriate permissions for a child process.
 775    This is like user_access, but you can't get back to make_access.  */
 776 void
 777 child_access (void)
 778 {
 779 #ifdef  GETLOADAVG_PRIVILEGED
 780
 781   if (!access_inited)
 782     abort ();
 783
 784   /* Set both the real and effective UID and GID to the user's.
 785      They cannot be changed back to make's.  */
 786
 787 #ifndef HAVE_SETREUID
 788   if (setuid (user_uid) < 0)
 789     pfatal_with_name ("child_access: setuid");
 790 #else
 791   if (setreuid (user_uid, user_uid) < 0)
 792     pfatal_with_name ("child_access: setreuid");
 793 #endif
 794
 795 #ifndef HAVE_SETREGID
 796   if (setgid (user_gid) < 0)
 797     pfatal_with_name ("child_access: setgid");
 798 #else
 799   if (setregid (user_gid, user_gid) < 0)
 800     pfatal_with_name ("child_access: setregid");
 801 #endif
 802
 803   log_access (_("Child access"));
 804
 805 #endif  /* GETLOADAVG_PRIVILEGED */
 806 }
 807 \f
 808 #ifdef NEED_GET_PATH_MAX
 809 unsigned int
 810 get_path_max (void)
 811 {
 812   static unsigned int value;
 813
 814   if (value == 0)
 815     {
 816       long int x = pathconf ("/", _PC_PATH_MAX);
 817       if (x > 0)
 818         value = x;
 819       else
 820         return MAXPATHLEN;
 821     }
 822
 823   return value;
 824 }
 825 #endif
 826 \f
 827
 828 /* This code is stolen from gnulib.
 829    If/when we abandon the requirement to work with K&R compilers, we can
 830    remove this (and perhaps other parts of GNU make!) and migrate to using
 831    gnulib directly.
 832
 833    This is called only through atexit(), which means die() has already been
 834    invoked.  So, call exit() here directly.  Apparently that works...?
 835 */
 836
 837 /* Close standard output, exiting with status 'exit_failure' on failure.
 838    If a program writes *anything* to stdout, that program should close
 839    stdout and make sure that it succeeds before exiting.  Otherwise,
 840    suppose that you go to the extreme of checking the return status
 841    of every function that does an explicit write to stdout.  The last
 842    printf can succeed in writing to the internal stream buffer, and yet
 843    the fclose(stdout) could still fail (due e.g., to a disk full error)
 844    when it tries to write out that buffered data.  Thus, you would be
 845    left with an incomplete output file and the offending program would
 846    exit successfully.  Even calling fflush is not always sufficient,
 847    since some file systems (NFS and CODA) buffer written/flushed data
 848    until an actual close call.
 849
 850    Besides, it's wasteful to check the return value from every call
 851    that writes to stdout -- just let the internal stream state record
 852    the failure.  That's what the ferror test is checking below.
 853
 854    It's important to detect such failures and exit nonzero because many
 855    tools (most notably `make' and other build-management systems) depend
 856    on being able to detect failure in other tools via their exit status.  */
 857
 858 void
 859 close_stdout (void)
 860 {
 861   int prev_fail = ferror (stdout);
 862   int fclose_fail = fclose (stdout);
 863
 864   if (prev_fail || fclose_fail)
 865     {
 866       if (fclose_fail)
 867         error (NILF, _("write error: %s"), strerror (errno));
 868       else
 869         error (NILF, _("write error"));
 870       exit (EXIT_FAILURE);
 871     }
 872 }