X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fidcache.c;h=8c1315f25729ff431a91400e696764b33e16563d;hb=86627bb14a123f183bd094e582e4cd9f2aca489a;hp=d4a867d7b9f5e84f3da4d5e1fab843219a8baa1e;hpb=0632e115747ff96e93330c88f536d7354a7ce507;p=gnulib.git

diff --git a/lib/idcache.c b/lib/idcache.c
index d4a867d7b..8c1315f25 100644
--- a/lib/idcache.c
+++ b/lib/idcache.c
@@ -1,12 +1,12 @@
 /* idcache.c -- map user and group IDs, cached for speed
 
-   Copyright (C) 1985, 1988, 1989, 1990, 1997, 1998, 2003, 2005, 2006
-   Free Software Foundation, Inc.
+   Copyright (C) 1985, 1988-1990, 1997-1998, 2003, 2005-2007, 2009-2012 Free
+   Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   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
@@ -14,14 +14,14 @@
    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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 
+#include "idcache.h"
+#include <stddef.h>
 #include <stdio.h>
 #include <string.h>
-#include <sys/types.h>
 #include <pwd.h>
 #include <grp.h>
 
@@ -40,36 +40,59 @@ struct userid
       uid_t u;
       gid_t g;
     } id;
-  char *name;
   struct userid *next;
+  char name[FLEXIBLE_ARRAY_MEMBER];
 };
 
+/* FIXME: provide a function to free any malloc'd storage and reset lists,
+   so that an application can use code like this just before exiting:
+   #ifdef lint
+     idcache_clear ();
+   #endif
+*/
+
 static struct userid *user_alist;
 
-/* The members of this list have names not in the local passwd file.  */
+/* Each entry on list is a user name for which the first lookup failed.  */
 static struct userid *nouser_alist;
 
+/* Use the same struct as for userids.  */
+static struct userid *group_alist;
+
+/* Each entry on list is a group name for which the first lookup failed.  */
+static struct userid *nogroup_alist;
+
 /* Translate UID to a login name, with cache, or NULL if unresolved.  */
 
 char *
 getuser (uid_t uid)
 {
-  register struct userid *tail;
-  struct passwd *pwent;
+  struct userid *tail;
+  struct userid *match = NULL;
 
   for (tail = user_alist; tail; tail = tail->next)
-    if (tail->id.u == uid)
-      return tail->name;
+    {
+      if (tail->id.u == uid)
+        {
+          match = tail;
+          break;
+        }
+    }
 
-  pwent = getpwuid (uid);
-  tail = xmalloc (sizeof *tail);
-  tail->id.u = uid;
-  tail->name = pwent ? xstrdup (pwent->pw_name) : NULL;
+  if (match == NULL)
+    {
+      struct passwd *pwent = getpwuid (uid);
+      char const *name = pwent ? pwent->pw_name : "";
+      match = xmalloc (offsetof (struct userid, name) + strlen (name) + 1);
+      match->id.u = uid;
+      strcpy (match->name, name);
+
+      /* Add to the head of the list, so most recently used is first.  */
+      match->next = user_alist;
+      user_alist = match;
+    }
 
-  /* Add to the head of the list, so most recently used is first.  */
-  tail->next = user_alist;
-  user_alist = tail;
-  return tail->name;
+  return match->name[0] ? match->name : NULL;
 }
 
 /* Translate USER to a UID, with cache.
@@ -80,7 +103,7 @@ getuser (uid_t uid)
 uid_t *
 getuidbyname (const char *user)
 {
-  register struct userid *tail;
+  struct userid *tail;
   struct passwd *pwent;
 
   for (tail = user_alist; tail; tail = tail->next)
@@ -91,7 +114,7 @@ getuidbyname (const char *user)
   for (tail = nouser_alist; tail; tail = tail->next)
     /* Avoid a function call for the most common case.  */
     if (*tail->name == *user && !strcmp (tail->name, user))
-      return 0;
+      return NULL;
 
   pwent = getpwnam (user);
 #ifdef __DJGPP__
@@ -100,12 +123,12 @@ getuidbyname (const char *user)
   if (!pwent && strspn (user, digits) < strlen (user))
     {
       setenv ("USER", user, 1);
-      pwent = getpwnam (user);	/* now it will succeed */
+      pwent = getpwnam (user);  /* now it will succeed */
     }
 #endif
 
-  tail = xmalloc (sizeof *tail);
-  tail->name = xstrdup (user);
+  tail = xmalloc (offsetof (struct userid, name) + strlen (user) + 1);
+  strcpy (tail->name, user);
 
   /* Add to the head of the list, so most recently used is first.  */
   if (pwent)
@@ -118,34 +141,40 @@ getuidbyname (const char *user)
 
   tail->next = nouser_alist;
   nouser_alist = tail;
-  return 0;
+  return NULL;
 }
 
-/* Use the same struct as for userids.  */
-static struct userid *group_alist;
-static struct userid *nogroup_alist;
-
 /* Translate GID to a group name, with cache, or NULL if unresolved.  */
 
 char *
 getgroup (gid_t gid)
 {
-  register struct userid *tail;
-  struct group *grent;
+  struct userid *tail;
+  struct userid *match = NULL;
 
   for (tail = group_alist; tail; tail = tail->next)
-    if (tail->id.g == gid)
-      return tail->name;
+    {
+      if (tail->id.g == gid)
+        {
+          match = tail;
+          break;
+        }
+    }
 
-  grent = getgrgid (gid);
-  tail = xmalloc (sizeof *tail);
-  tail->id.g = gid;
-  tail->name = grent ? xstrdup (grent->gr_name) : NULL;
+  if (match == NULL)
+    {
+      struct group *grent = getgrgid (gid);
+      char const *name = grent ? grent->gr_name : "";
+      match = xmalloc (offsetof (struct userid, name) + strlen (name) + 1);
+      match->id.g = gid;
+      strcpy (match->name, name);
+
+      /* Add to the head of the list, so most recently used is first.  */
+      match->next = group_alist;
+      group_alist = match;
+    }
 
-  /* Add to the head of the list, so most recently used is first.  */
-  tail->next = group_alist;
-  group_alist = tail;
-  return tail->name;
+  return match->name[0] ? match->name : NULL;
 }
 
 /* Translate GROUP to a GID, with cache.
@@ -156,7 +185,7 @@ getgroup (gid_t gid)
 gid_t *
 getgidbyname (const char *group)
 {
-  register struct userid *tail;
+  struct userid *tail;
   struct group *grent;
 
   for (tail = group_alist; tail; tail = tail->next)
@@ -167,21 +196,21 @@ getgidbyname (const char *group)
   for (tail = nogroup_alist; tail; tail = tail->next)
     /* Avoid a function call for the most common case.  */
     if (*tail->name == *group && !strcmp (tail->name, group))
-      return 0;
+      return NULL;
 
   grent = getgrnam (group);
 #ifdef __DJGPP__
   /* We need to pretend to belong to group GROUP, to make
-     grp functions know about any arbitrary group name.  */
+     grp functions know about an arbitrary group name.  */
   if (!grent && strspn (group, digits) < strlen (group))
     {
       setenv ("GROUP", group, 1);
-      grent = getgrnam (group);	/* now it will succeed */
+      grent = getgrnam (group); /* now it will succeed */
     }
 #endif
 
-  tail = xmalloc (sizeof *tail);
-  tail->name = xstrdup (group);
+  tail = xmalloc (offsetof (struct userid, name) + strlen (group) + 1);
+  strcpy (tail->name, group);
 
   /* Add to the head of the list, so most recently used is first.  */
   if (grent)
@@ -194,5 +223,5 @@ getgidbyname (const char *group)
 
   tail->next = nogroup_alist;
   nogroup_alist = tail;
-  return 0;
+  return NULL;
 }