Fix indentation in previous patch.

[gnulib.git] / lib / getgroups.c

diff --git a/lib/getgroups.c b/lib/getgroups.c
index a72bddb..482b24a 100644 (file)
--- a/lib/getgroups.c
+++ b/lib/getgroups.c
@@ -1,10 +1,11 @@
 /* provide consistent interface to getgroups for systems that don't allow N==0
-   Copyright (C) 1996 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   Copyright (C) 1996, 1999, 2003, 2006-2013 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -12,48 +13,119 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software Foundation,
-   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 /* written by Jim Meyering */
 
 #include <config.h>
-#include <stdio.h>
-#include <sys/types.h>
 
-char *xmalloc ();
+#include <unistd.h>
+
+#include <errno.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+#if !HAVE_GETGROUPS
+
+/* Provide a stub that fails with ENOSYS, since there is no group
+   information available on mingw.  */
+int
+getgroups (int n _GL_UNUSED, GETGROUPS_T *groups _GL_UNUSED)
+{
+  errno = ENOSYS;
+  return -1;
+}
+
+#else /* HAVE_GETGROUPS */
 
-/* On at least Ultrix 4.3 and NextStep 3.2, getgroups (0, 0) always fails.
-   On other systems, it returns the number of supplemental groups for the
-   process is returned.
-   This function handles that special case and lets the system-
-   provided function handle all others.  */
+# undef getgroups
+# ifndef GETGROUPS_ZERO_BUG
+#  define GETGROUPS_ZERO_BUG 0
+# endif
+
+/* On OS X 10.6 and later, use the usual getgroups, not the one
+   supplied when _DARWIN_C_SOURCE is defined.  _DARWIN_C_SOURCE is
+   normally defined, since it means "conform to POSIX, but add
+   non-POSIX extensions even if that violates the POSIX namespace
+   rules", which is what we normally want.  But with getgroups there
+   is an inconsistency, and _DARWIN_C_SOURCE means "change getgroups()
+   so that it no longer works right".  The BUGS section of compat(5)
+   says that the behavior is dubious if you compile different sections
+   of a program with different _DARWIN_C_SOURCE settings, so fix only
+   the offending symbol.  */
+# ifdef __APPLE__
+int posix_getgroups (int, gid_t []) __asm ("_getgroups");
+#  define getgroups posix_getgroups
+# endif
+
+/* On at least Ultrix 4.3 and NextStep 3.2, getgroups (0, NULL) always
+   fails.  On other systems, it returns the number of supplemental
+   groups for the process.  This function handles that special case
+   and lets the system-provided function handle all others.  However,
+   it can fail with ENOMEM if memory is tight.  It is unspecified
+   whether the effective group id is included in the list.  */
 
 int
-getgroups (n, group)
-     size_t n;
-     GETGROUPS_T *group;
+rpl_getgroups (int n, gid_t *group)
 {
   int n_groups;
   GETGROUPS_T *gbuf;
+  int saved_errno;
+
+  if (n < 0)
+    {
+      errno = EINVAL;
+      return -1;
+    }
 
-#undef getgroups
+  if (n != 0 || !GETGROUPS_ZERO_BUG)
+    {
+      int result;
+      if (sizeof *group == sizeof *gbuf)
+        return getgroups (n, (GETGROUPS_T *) group);
 
-  if (n != 0)
-    return getgroups (n, group);
+      if (SIZE_MAX / sizeof *gbuf <= n)
+        {
+          errno = ENOMEM;
+          return -1;
+        }
+      gbuf = malloc (n * sizeof *gbuf);
+      if (!gbuf)
+        return -1;
+      result = getgroups (n, gbuf);
+      if (0 <= result)
+        {
+          n = result;
+          while (n--)
+            group[n] = gbuf[n];
+        }
+      saved_errno = errno;
+      free (gbuf);
+      errno = saved_errno;
+      return result;
+    }
 
   n = 20;
-  gbuf = NULL;
   while (1)
     {
-      gbuf = (GETGROUPS_T *) xrealloc (gbuf, n * sizeof (GETGROUPS_T));
+      /* No need to worry about address arithmetic overflow here,
+         since the ancient systems that we're running on have low
+         limits on the number of secondary groups.  */
+      gbuf = malloc (n * sizeof *gbuf);
+      if (!gbuf)
+        return -1;
       n_groups = getgroups (n, gbuf);
-      if (n_groups < n)
-       break;
-      n += 10;
+      if (n_groups == -1 ? errno != EINVAL : n_groups < n)
+        break;
+      free (gbuf);
+      n *= 2;
     }
 
+  saved_errno = errno;
   free (gbuf);
+  errno = saved_errno;
 
   return n_groups;
 }
+
+#endif /* HAVE_GETGROUPS */