diff options
Diffstat (limited to 'grp/initgroups.c')
| -rw-r--r-- | grp/initgroups.c | 67 |
1 files changed, 45 insertions, 22 deletions
diff --git a/grp/initgroups.c b/grp/initgroups.c index 5af1926742..a700557924 100644 --- a/grp/initgroups.c +++ b/grp/initgroups.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1989, 1991, 1993 Free Software Foundation, Inc. +/* Copyright (C) 1989, 1991, 1993, 1996 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -31,43 +31,66 @@ int DEFUN(initgroups, (user, group), CONST char *user AND gid_t group) { -#ifdef NGROUPS_MAX -#if NGROUPS_MAX == 0 +#if defined (NGROUPS_MAX) && NGROUPS_MAX == 0 + + /* No extra groups allowed. */ return 0; + #else - static PTR info = NULL; - register FILE *stream; - register struct group *g; - gid_t groups[NGROUPS_MAX]; + + struct group *g; register size_t n; +#ifdef NGROUPS_MAX + gid_t groups[NGROUPS_MAX]; +#else + long int limit = sysconf (_SC_NGROUPS_MAX); + gid_t *groups; + size_t ngroups; - if (info == NULL) - { - info = __grpalloc(); - if (info == NULL) - return -1; - } + if (limit > 0) + ngroups = limit; + else + /* No fixed limit on groups. Pick a starting buffer size. */ + ngroups = 16; - stream = __grpopen(); - if (stream == NULL) - return -1; + groups = __alloca (ngroups * sizeof *groups); +#endif + + setgrent (); n = 0; groups[n++] = group; - while (n < NGROUPS_MAX && (g = __grpread(stream, info)) != NULL) + while ((g = getgrent ()) != NULL) if (g->gr_gid != group) { register char **m; for (m = g->gr_mem; *m != NULL; ++m) - if (!strcmp(*m, user)) + if (!strcmp (*m, user)) + break; + + if (*m == NULL) + { + /* Matched the user. Insert this group. */ + if (n == ngroups && limit <= 0) + { + /* Need a bigger buffer. */ + groups = memcpy (__alloca (ngroups * 2 * sizeof *groups), + groups, ngroups * sizeof *groups); + ngroups *= 2; + } + groups[n++] = g->gr_gid; + + if (n == limit) + /* Can't take any more groups; stop searching. */ + break; + } } - return setgroups(n, groups); -#endif -#else - return 0; + endgrent (); + + return setgroups (n, groups); #endif } |