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-rw-r--r--grp/initgroups.c67
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
}