src/utilunix.c

   1 /* Various utilities - Unix variants
   2    Copyright (C) 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003,
   3    2004, 2005, 2007 Free Software Foundation, Inc.
   4    Written 1994, 1995, 1996 by:
   5    Miguel de Icaza, Janne Kukonlehto, Dugan Porter,
   6    Jakub Jelinek, Mauricio Plaza.
   7
   8    The mc_realpath routine is mostly from uClibc package, written
   9    by Rick Sladkey <jrs@world.std.com>
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 2 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program; if not, write to the Free Software
  23    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  24
  25 #include <config.h>
  26
  27 #include <ctype.h>
  28 #include <errno.h>
  29 #include <limits.h>
  30 #include <signal.h>
  31 #include <stdarg.h>
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35
  36 #include <sys/param.h>
  37 #include <sys/types.h>
  38 #include <sys/stat.h>
  39 #ifdef HAVE_SYS_IOCTL_H
  40 #   include <sys/ioctl.h>
  41 #endif
  42 #include <unistd.h>
  43
  44 #include <mhl/types.h>
  45 #include <mhl/memory.h>
  46 #include <mhl/string.h>
  47
  48 #include "global.h"
  49 #include "execute.h"
  50 #include "wtools.h"             /* message() */
  51
  52 struct sigaction startup_handler;
  53
  54 #define UID_CACHE_SIZE 200
  55 #define GID_CACHE_SIZE 30
  56
  57 typedef struct {
  58     int  index;
  59     char *string;
  60 } int_cache;
  61
  62 static int_cache uid_cache [UID_CACHE_SIZE];
  63 static int_cache gid_cache [GID_CACHE_SIZE];
  64
  65 static char *i_cache_match (int id, int_cache *cache, int size)
  66 {
  67     int i;
  68
  69     for (i = 0; i < size; i++)
  70         if (cache [i].index == id)
  71             return cache [i].string;
  72     return 0;
  73 }
  74
  75 static void i_cache_add (int id, int_cache *cache, int size, char *text,
  76                          int *last)
  77 {
  78     g_free (cache [*last].string);
  79     cache [*last].string = mhl_str_dup (text);
  80     cache [*last].index = id;
  81     *last = ((*last)+1) % size;
  82 }
  83
  84 char *get_owner (int uid)
  85 {
  86     struct passwd *pwd;
  87     static char ibuf [10];
  88     char   *name;
  89     static int uid_last;
  90
  91     if ((name = i_cache_match (uid, uid_cache, UID_CACHE_SIZE)) != NULL)
  92         return name;
  93
  94     pwd = getpwuid (uid);
  95     if (pwd){
  96         i_cache_add (uid, uid_cache, UID_CACHE_SIZE, pwd->pw_name, &uid_last);
  97         return pwd->pw_name;
  98     }
  99     else {
 100         snprintf (ibuf, sizeof (ibuf), "%d", uid);
 101         return ibuf;
 102     }
 103 }
 104
 105 char *get_group (int gid)
 106 {
 107     struct group *grp;
 108     static char gbuf [10];
 109     char *name;
 110     static int  gid_last;
 111
 112     if ((name = i_cache_match (gid, gid_cache, GID_CACHE_SIZE)) != NULL)
 113         return name;
 114
 115     grp = getgrgid (gid);
 116     if (grp){
 117         i_cache_add (gid, gid_cache, GID_CACHE_SIZE, grp->gr_name, &gid_last);
 118         return grp->gr_name;
 119     } else {
 120         snprintf (gbuf, sizeof (gbuf), "%d", gid);
 121         return gbuf;
 122     }
 123 }
 124
 125 /* Since ncurses uses a handler that automatically refreshes the */
 126 /* screen after a SIGCONT, and we don't want this behavior when */
 127 /* spawning a child, we save the original handler here */
 128 void save_stop_handler (void)
 129 {
 130     sigaction (SIGTSTP, NULL, &startup_handler);
 131 }
 132
 133 int my_system (int flags, const char *shell, const char *command)
 134 {
 135     struct sigaction ignore, save_intr, save_quit, save_stop;
 136     pid_t pid;
 137     int status = 0;
 138
 139     ignore.sa_handler = SIG_IGN;
 140     sigemptyset (&ignore.sa_mask);
 141     ignore.sa_flags = 0;
 142
 143     sigaction (SIGINT, &ignore, &save_intr);
 144     sigaction (SIGQUIT, &ignore, &save_quit);
 145
 146     /* Restore the original SIGTSTP handler, we don't want ncurses' */
 147     /* handler messing the screen after the SIGCONT */
 148     sigaction (SIGTSTP, &startup_handler, &save_stop);
 149
 150     if ((pid = fork ()) < 0){
 151         fprintf (stderr, "\n\nfork () = -1\n");
 152         return -1;
 153     }
 154     if (pid == 0){
 155         signal (SIGINT, SIG_DFL);
 156         signal (SIGQUIT, SIG_DFL);
 157         signal (SIGTSTP, SIG_DFL);
 158         signal (SIGCHLD, SIG_DFL);
 159
 160         if (flags & EXECUTE_AS_SHELL)
 161             execl (shell, shell, "-c", command, (char *) NULL);
 162         else
 163             execlp (shell, shell, command, (char *) NULL);
 164
 165         _exit (127);            /* Exec error */
 166     } else {
 167         while (waitpid (pid, &status, 0) < 0)
 168             if (errno != EINTR){
 169                 status = -1;
 170                 break;
 171             }
 172     }
 173     sigaction (SIGINT,  &save_intr, NULL);
 174     sigaction (SIGQUIT, &save_quit, NULL);
 175     sigaction (SIGTSTP, &save_stop, NULL);
 176
 177     return WEXITSTATUS(status);
 178 }
 179
 180
 181 /*
 182  * Perform tilde expansion if possible.
 183  * Always return a newly allocated string, even if it's unchanged.
 184  */
 185 char *
 186 tilde_expand (const char *directory)
 187 {
 188     struct passwd *passwd;
 189     const char *p, *q;
 190     char *name;
 191
 192     if (*directory != '~')
 193         return mhl_str_dup (directory);
 194
 195     p = directory + 1;
 196
 197     /* d = "~" or d = "~/" */
 198     if (!(*p) || (*p == PATH_SEP)) {
 199         passwd = getpwuid (geteuid ());
 200         q = (*p == PATH_SEP) ? p + 1 : "";
 201     } else {
 202         q = strchr (p, PATH_SEP);
 203         if (!q) {
 204             passwd = getpwnam (p);
 205         } else {
 206             name = g_strndup (p, q - p);
 207             passwd = getpwnam (name);
 208             q++;
 209             g_free (name);
 210         }
 211     }
 212
 213     /* If we can't figure the user name, leave tilde unexpanded */
 214     if (!passwd)
 215         return mhl_str_dup (directory);
 216
 217     return g_strconcat (passwd->pw_dir, PATH_SEP_STR, q, (char *) NULL);
 218 }
 219
 220 static void
 221 mc_setenv (const char *name, const char *value, int overwrite_flag)
 222 {
 223 #if defined(HAVE_SETENV)
 224     setenv (name, value, overwrite_flag);
 225 #else
 226     if (overwrite_flag || getenv (name) == NULL)
 227         putenv (g_strconcat (name, "=", value, (char *) NULL));
 228 #endif
 229 }
 230
 231 /*
 232  * Return the directory where mc should keep its temporary files.
 233  * This directory is (in Bourne shell terms) "${TMPDIR=/tmp}/mc-$USER"
 234  * When called the first time, the directory is created if needed.
 235  * The first call should be done early, since we are using fprintf()
 236  * and not message() to report possible problems.
 237  */
 238 const char *
 239 mc_tmpdir (void)
 240 {
 241     static char buffer[64];
 242     static const char *tmpdir;
 243     const char *sys_tmp;
 244     struct passwd *pwd;
 245     struct stat st;
 246     const char *error = NULL;
 247
 248     /* Check if already correctly initialized */
 249     if (tmpdir && lstat (tmpdir, &st) == 0 && S_ISDIR (st.st_mode) &&
 250         st.st_uid == getuid () && (st.st_mode & 0777) == 0700)
 251         return tmpdir;
 252
 253     sys_tmp = getenv ("TMPDIR");
 254     if (!sys_tmp || sys_tmp[0] != '/') {
 255         sys_tmp = TMPDIR_DEFAULT;
 256     }
 257
 258     pwd = getpwuid (getuid ());
 259
 260     if (pwd)
 261         snprintf (buffer, sizeof (buffer), "%s/mc-%s", sys_tmp,
 262                 pwd->pw_name);
 263     else
 264         snprintf (buffer, sizeof (buffer), "%s/mc-%lu", sys_tmp,
 265                 (unsigned long) getuid ());
 266
 267     canonicalize_pathname (buffer);
 268
 269     if (lstat (buffer, &st) == 0) {
 270         /* Sanity check for existing directory */
 271         if (!S_ISDIR (st.st_mode))
 272             error = _("%s is not a directory\n");
 273         else if (st.st_uid != getuid ())
 274             error = _("Directory %s is not owned by you\n");
 275         else if (((st.st_mode & 0777) != 0700)
 276                  && (chmod (buffer, 0700) != 0))
 277             error = _("Cannot set correct permissions for directory %s\n");
 278     } else {
 279         /* Need to create directory */
 280         if (mkdir (buffer, S_IRWXU) != 0) {
 281             fprintf (stderr,
 282                      _("Cannot create temporary directory %s: %s\n"),
 283                      buffer, unix_error_string (errno));
 284             error = "";
 285         }
 286     }
 287
 288     if (error != NULL) {
 289         int test_fd;
 290         char *test_fn, *fallback_prefix;
 291         int fallback_ok = 0;
 292
 293         if (*error)
 294             fprintf (stderr, error, buffer);
 295
 296         /* Test if sys_tmp is suitable for temporary files */
 297         fallback_prefix = g_strdup_printf ("%s/mctest", sys_tmp);
 298         test_fd = mc_mkstemps (&test_fn, fallback_prefix, NULL);
 299         g_free (fallback_prefix);
 300         if (test_fd != -1) {
 301             close (test_fd);
 302             test_fd = open (test_fn, O_RDONLY);
 303             if (test_fd != -1) {
 304                 close (test_fd);
 305                 unlink (test_fn);
 306                 fallback_ok = 1;
 307             }
 308         }
 309
 310         if (fallback_ok) {
 311             fprintf (stderr, _("Temporary files will be created in %s\n"),
 312                      sys_tmp);
 313             snprintf (buffer, sizeof (buffer), "%s", sys_tmp);
 314             error = NULL;
 315         } else {
 316             fprintf (stderr, _("Temporary files will not be created\n"));
 317             snprintf (buffer, sizeof (buffer), "%s", "/dev/null/");
 318         }
 319
 320         fprintf (stderr, "%s\n", _("Press any key to continue..."));
 321         getc (stdin);
 322     }
 323
 324     tmpdir = buffer;
 325
 326     if (!error)
 327         mc_setenv ("MC_TMPDIR", tmpdir, 1);
 328
 329     return tmpdir;
 330 }
 331
 332
 333 /* Pipes are guaranteed to be able to hold at least 4096 bytes */
 334 /* More than that would be unportable */
 335 #define MAX_PIPE_SIZE 4096
 336
 337 static int error_pipe[2];       /* File descriptors of error pipe */
 338 static int old_error;           /* File descriptor of old standard error */
 339
 340 /* Creates a pipe to hold standard error for a later analysis. */
 341 /* The pipe can hold 4096 bytes. Make sure no more is written */
 342 /* or a deadlock might occur. */
 343 void open_error_pipe (void)
 344 {
 345     if (pipe (error_pipe) < 0){
 346         message (D_NORMAL, _("Warning"), _(" Pipe failed "));
 347     }
 348     old_error = dup (2);
 349     if(old_error < 0 || close(2) || dup (error_pipe[1]) != 2){
 350         message (D_NORMAL, _("Warning"), _(" Dup failed "));
 351         close (error_pipe[0]);
 352         close (error_pipe[1]);
 353     }
 354     close (error_pipe[1]);
 355 }
 356
 357 /*
 358  * Returns true if an error was displayed
 359  * error: -1 - ignore errors, 0 - display warning, 1 - display error
 360  * text is prepended to the error message from the pipe
 361  */
 362 int
 363 close_error_pipe (int error, const char *text)
 364 {
 365     const char *title;
 366     char msg[MAX_PIPE_SIZE];
 367     int len = 0;
 368
 369     if (error)
 370         title = MSG_ERROR;
 371     else
 372         title = _("Warning");
 373     if (old_error >= 0){
 374         close (2);
 375         dup (old_error);
 376         close (old_error);
 377         len = read (error_pipe[0], msg, MAX_PIPE_SIZE - 1);
 378
 379         if (len >= 0)
 380             msg[len] = 0;
 381         close (error_pipe[0]);
 382     }
 383     if (error < 0)
 384         return 0;       /* Just ignore error message */
 385     if (text == NULL){
 386         if (len <= 0)
 387             return 0;   /* Nothing to show */
 388
 389         /* Show message from pipe */
 390         message (error, title, "%s", msg);
 391     } else {
 392         /* Show given text and possible message from pipe */
 393         message (error, title, " %s \n %s ", text, msg);
 394     }
 395     return 1;
 396 }
 397
 398 /*
 399  * Canonicalize path, and return a new path.  Do everything in place.
 400  * The new path differs from path in:
 401  *      Multiple `/'s are collapsed to a single `/'.
 402  *      Leading `./'s and trailing `/.'s are removed.
 403  *      Trailing `/'s are removed.
 404  *      Non-leading `../'s and trailing `..'s are handled by removing
 405  *      portions of the path.
 406  * Well formed UNC paths are modified only in the local part.
 407  */
 408 void
 409 canonicalize_pathname (char *path)
 410 {
 411     char *p, *s;
 412     int len;
 413     char *lpath = path; /* path without leading UNC part */
 414
 415     /* Detect and preserve UNC paths: //server/... */
 416     if (path[0] == PATH_SEP && path[1] == PATH_SEP) {
 417         p = path + 2;
 418         while (p[0] && p[0] != '/')
 419             p++;
 420         if (p[0] == '/' && p > path + 2)
 421             lpath = p;
 422     }
 423
 424     if (!lpath[0] || !lpath[1])
 425         return;
 426
 427     /* Collapse multiple slashes */
 428     p = lpath;
 429     while (*p) {
 430         if (p[0] == PATH_SEP && p[1] == PATH_SEP) {
 431             s = p + 1;
 432             while (*(++s) == PATH_SEP);
 433             mhl_strmove (p + 1, s);
 434         }
 435         p++;
 436     }
 437
 438     /* Collapse "/./" -> "/" */
 439     p = lpath;
 440     while (*p) {
 441         if (p[0] == PATH_SEP && p[1] == '.' && p[2] == PATH_SEP)
 442             mhl_strmove (p, p + 2);
 443         else
 444             p++;
 445     }
 446
 447     /* Remove trailing slashes */
 448     p = lpath + strlen (lpath) - 1;
 449     while (p > lpath && *p == PATH_SEP)
 450         *p-- = 0;
 451
 452     /* Remove leading "./" */
 453     if (lpath[0] == '.' && lpath[1] == PATH_SEP) {
 454         if (lpath[2] == 0) {
 455             lpath[1] = 0;
 456             return;
 457         } else {
 458             mhl_strmove (lpath, lpath + 2);
 459         }
 460     }
 461
 462     /* Remove trailing "/" or "/." */
 463     len = strlen (lpath);
 464     if (len < 2)
 465         return;
 466     if (lpath[len - 1] == PATH_SEP) {
 467         lpath[len - 1] = 0;
 468     } else {
 469         if (lpath[len - 1] == '.' && lpath[len - 2] == PATH_SEP) {
 470             if (len == 2) {
 471                 lpath[1] = 0;
 472                 return;
 473             } else {
 474                 lpath[len - 2] = 0;
 475             }
 476         }
 477     }
 478
 479     /* Collapse "/.." with the previous part of path */
 480     p = lpath;
 481     while (p[0] && p[1] && p[2]) {
 482         if ((p[0] != PATH_SEP || p[1] != '.' || p[2] != '.')
 483             || (p[3] != PATH_SEP && p[3] != 0)) {
 484             p++;
 485             continue;
 486         }
 487
 488         /* search for the previous token */
 489         s = p - 1;
 490         while (s >= lpath && *s != PATH_SEP)
 491             s--;
 492
 493         s++;
 494
 495         /* If the previous token is "..", we cannot collapse it */
 496         if (s[0] == '.' && s[1] == '.' && s + 2 == p) {
 497             p += 3;
 498             continue;
 499         }
 500
 501         if (p[3] != 0) {
 502             if (s == lpath && *s == PATH_SEP) {
 503                 /* "/../foo" -> "/foo" */
 504                 mhl_strmove (s + 1, p + 4);
 505             } else {
 506                 /* "token/../foo" -> "foo" */
 507                 mhl_strmove (s, p + 4);
 508             }
 509             p = (s > lpath) ? s - 1 : s;
 510             continue;
 511         }
 512
 513         /* trailing ".." */
 514         if (s == lpath) {
 515             /* "token/.." -> "." */
 516             if (lpath[0] != PATH_SEP) {
 517                 lpath[0] = '.';
 518             }
 519             lpath[1] = 0;
 520         } else {
 521             /* "foo/token/.." -> "foo" */
 522             if (s == lpath + 1)
 523                 s[0] = 0;
 524             else
 525                 s[-1] = 0;
 526             break;
 527         }
 528
 529         break;
 530     }
 531 }
 532
 533 #ifdef HAVE_GET_PROCESS_STATS
 534 #    include <sys/procstats.h>
 535
 536 int gettimeofday (struct timeval *tp, void *tzp)
 537 {
 538   return get_process_stats(tp, PS_SELF, 0, 0);
 539 }
 540 #endif /* HAVE_GET_PROCESS_STATS */
 541
 542 #ifndef HAVE_PUTENV
 543
 544 /* The following piece of code was copied from the GNU C Library */
 545 /* And is provided here for nextstep who lacks putenv */
 546
 547 extern char **environ;
 548
 549 #ifndef HAVE_GNU_LD
 550 #define __environ       environ
 551 #endif
 552
 553
 554 /* Put STRING, which is of the form "NAME=VALUE", in the environment.  */
 555 int
 556 putenv (char *string)
 557 {
 558     const char *const name_end = strchr (string, '=');
 559     register size_t size;
 560     register char **ep;
 561
 562     if (name_end == NULL){
 563         /* Remove the variable from the environment.  */
 564         size = strlen (string);
 565         for (ep = __environ; *ep != NULL; ++ep)
 566             if (!strncmp (*ep, string, size) && (*ep)[size] == '='){
 567                 while (ep[1] != NULL){
 568                     ep[0] = ep[1];
 569                     ++ep;
 570                 }
 571                 *ep = NULL;
 572                 return 0;
 573             }
 574     }
 575
 576     size = 0;
 577     for (ep = __environ; *ep != NULL; ++ep)
 578         if (!strncmp (*ep, string, name_end - string) &&
 579             (*ep)[name_end - string] == '=')
 580             break;
 581         else
 582             ++size;
 583
 584     if (*ep == NULL){
 585         static char **last_environ = NULL;
 586         char **new_environ = g_new (char *, size + 2);
 587         if (new_environ == NULL)
 588             return -1;
 589         (void) memcpy ((void *) new_environ, (void *) __environ,
 590                        size * sizeof (char *));
 591         new_environ[size] = (char *) string;
 592         new_environ[size + 1] = NULL;
 593         g_free ((void *) last_environ);
 594         last_environ = new_environ;
 595         __environ = new_environ;
 596     }
 597     else
 598         *ep = (char *) string;
 599
 600     return 0;
 601 }
 602 #endif /* !HAVE_PUTENV */
 603
 604 char *
 605 mc_realpath (const char *path, char resolved_path[])
 606 {
 607 #ifdef  USE_SYSTEM_REALPATH
 608     return realpath (path, resolved_path);
 609 #else
 610     char copy_path[PATH_MAX];
 611     char link_path[PATH_MAX];
 612     char got_path[PATH_MAX];
 613     char *new_path = got_path;
 614     char *max_path;
 615     int readlinks = 0;
 616     int n;
 617
 618     /* Make a copy of the source path since we may need to modify it. */
 619     if (strlen (path) >= PATH_MAX - 2) {
 620         errno = ENAMETOOLONG;
 621         return NULL;
 622     }
 623     strcpy (copy_path, path);
 624     path = copy_path;
 625     max_path = copy_path + PATH_MAX - 2;
 626     /* If it's a relative pathname use getwd for starters. */
 627     if (*path != '/') {
 628         /* Ohoo... */
 629 #ifdef HAVE_GETCWD
 630         getcwd (new_path, PATH_MAX - 1);
 631 #else
 632         getwd (new_path);
 633 #endif
 634         new_path += strlen (new_path);
 635         if (new_path[-1] != '/')
 636             *new_path++ = '/';
 637     } else {
 638         *new_path++ = '/';
 639         path++;
 640     }
 641     /* Expand each slash-separated pathname component. */
 642     while (*path != '\0') {
 643         /* Ignore stray "/". */
 644         if (*path == '/') {
 645             path++;
 646             continue;
 647         }
 648         if (*path == '.') {
 649             /* Ignore ".". */
 650             if (path[1] == '\0' || path[1] == '/') {
 651                 path++;
 652                 continue;
 653             }
 654             if (path[1] == '.') {
 655                 if (path[2] == '\0' || path[2] == '/') {
 656                     path += 2;
 657                     /* Ignore ".." at root. */
 658                     if (new_path == got_path + 1)
 659                         continue;
 660                     /* Handle ".." by backing up. */
 661                     while ((--new_path)[-1] != '/');
 662                     continue;
 663                 }
 664             }
 665         }
 666         /* Safely copy the next pathname component. */
 667         while (*path != '\0' && *path != '/') {
 668             if (path > max_path) {
 669                 errno = ENAMETOOLONG;
 670                 return NULL;
 671             }
 672             *new_path++ = *path++;
 673         }
 674 #ifdef S_IFLNK
 675         /* Protect against infinite loops. */
 676         if (readlinks++ > MAXSYMLINKS) {
 677             errno = ELOOP;
 678             return NULL;
 679         }
 680         /* See if latest pathname component is a symlink. */
 681         *new_path = '\0';
 682         n = readlink (got_path, link_path, PATH_MAX - 1);
 683         if (n < 0) {
 684             /* EINVAL means the file exists but isn't a symlink. */
 685             if (errno != EINVAL) {
 686                 /* Make sure it's null terminated. */
 687                 *new_path = '\0';
 688                 strcpy (resolved_path, got_path);
 689                 return NULL;
 690             }
 691         } else {
 692             /* Note: readlink doesn't add the null byte. */
 693             link_path[n] = '\0';
 694             if (*link_path == '/')
 695                 /* Start over for an absolute symlink. */
 696                 new_path = got_path;
 697             else
 698                 /* Otherwise back up over this component. */
 699                 while (*(--new_path) != '/');
 700             /* Safe sex check. */
 701             if (strlen (path) + n >= PATH_MAX - 2) {
 702                 errno = ENAMETOOLONG;
 703                 return NULL;
 704             }
 705             /* Insert symlink contents into path. */
 706             strcat (link_path, path);
 707             strcpy (copy_path, link_path);
 708             path = copy_path;
 709         }
 710 #endif                          /* S_IFLNK */
 711         *new_path++ = '/';
 712     }
 713     /* Delete trailing slash but don't whomp a lone slash. */
 714     if (new_path != got_path + 1 && new_path[-1] == '/')
 715         new_path--;
 716     /* Make sure it's null terminated. */
 717     *new_path = '\0';
 718     strcpy (resolved_path, got_path);
 719     return resolved_path;
 720 #endif  /* USE_SYSTEM_REALPATH */
 721 }
 722
 723 /* Return the index of the permissions triplet */
 724 int
 725 get_user_permissions (struct stat *st) {
 726     static bool initialized = FALSE;
 727     static gid_t *groups;
 728     static int ngroups;
 729     static uid_t uid;
 730     int i;
 731
 732     if (!initialized) {
 733         uid = geteuid ();
 734
 735         ngroups = getgroups (0, NULL);
 736         if (ngroups == -1)
 737             ngroups = 0;        /* ignore errors */
 738
 739         /* allocate space for one element in addition to what
 740          * will be filled by getgroups(). */
 741         groups = g_new (gid_t, ngroups + 1);
 742
 743         if (ngroups != 0) {
 744             ngroups = getgroups (ngroups, groups);
 745             if (ngroups == -1)
 746                 ngroups = 0;    /* ignore errors */
 747         }
 748
 749         /* getgroups() may or may not return the effective group ID,
 750          * so we always include it at the end of the list. */
 751         groups[ngroups++] = getegid ();
 752
 753         initialized = TRUE;
 754     }
 755
 756     if (st->st_uid == uid || uid == 0)
 757        return 0;
 758
 759     for (i = 0; i < ngroups; i++) {
 760         if (st->st_gid == groups[i])
 761             return 1;
 762     }
 763
 764     return 2;
 765 }