Implement caching of nscd

1 files changed, 290 insertions, 0 deletions

diff --git a/nscd/nscd_netgroup.c b/nscd/nscd_netgroup.c
new file mode 100644
index 0000000..8457cec
--- /dev/null
+++ b/nscd/nscd_netgroup.c
@@ -0,0 +1,290 @@
+/* Copyright (C) 2011 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <alloca.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <not-cancel.h>
+
+#include "nscd-client.h"
+#include "nscd_proto.h"
+
+int __nss_not_use_nscd_netgroup;
+
+
+libc_locked_map_ptr (static, map_handle);
+/* Note that we only free the structure if necessary.  The memory
+   mapping is not removed since it is not visible to the malloc
+   handling.  */
+libc_freeres_fn (pw_map_free)
+{
+  if (map_handle.mapped != NO_MAPPING)
+    {
+      void *p = map_handle.mapped;
+      map_handle.mapped = NO_MAPPING;
+      free (p);
+    }
+}
+
+
+int
+__nscd_setnetgrent (const char *group, struct __netgrent *datap)
+{
+  int gc_cycle;
+  int nretries = 0;
+  size_t group_len = strlen (group);
+
+  /* If the mapping is available, try to search there instead of
+     communicating with the nscd.  */
+  struct mapped_database *mapped;
+  mapped = __nscd_get_map_ref (GETFDNETGR, "netgroup", &map_handle, &gc_cycle);
+
+ retry:;
+  char *respdata = NULL;
+  int retval = -1;
+  netgroup_response_header netgroup_resp;
+
+  if (mapped != NO_MAPPING)
+    {
+      struct datahead *found = __nscd_cache_search (GETNETGRENT, group,
+						    group_len, mapped,
+						    sizeof netgroup_resp);
+      if (found != NULL)
+	{
+	  respdata = (char *) (&found->data[0].netgroupdata + 1);
+	  netgroup_resp = found->data[0].netgroupdata;
+	  /* Now check if we can trust pw_resp fields.  If GC is
+	     in progress, it can contain anything.  */
+	  if (mapped->head->gc_cycle != gc_cycle)
+	    {
+	      retval = -2;
+	      goto out;
+	    }
+	}
+    }
+
+  int sock = -1;
+  if (respdata == NULL)
+    {
+      sock = __nscd_open_socket (group, group_len, GETNETGRENT,
+				 &netgroup_resp, sizeof (netgroup_resp));
+      if (sock == -1)
+	{
+	  /* nscd not running or wrong version.  */
+	  __nss_not_use_nscd_netgroup = 1;
+	  goto out;
+	}
+    }
+
+  if (netgroup_resp.found == 1)
+    {
+      size_t datalen = netgroup_resp.result_len;
+
+      /* If we do not have to read the data here it comes from the
+	 mapped data and does not have to be freed.  */
+      if (respdata == NULL)
+	{
+	  /* The data will come via the socket.  */
+	  respdata = malloc (datalen);
+	  if (respdata == NULL)
+	    goto out_close;
+
+	  if ((size_t) __readall (sock, respdata, datalen) != datalen)
+	    {
+	      free (respdata);
+	      goto out_close;
+	    }
+	}
+
+      datap->data = respdata;
+      datap->data_size = datalen;
+      datap->cursor = respdata;
+      datap->first = 1;
+      datap->nip = (service_user *) -1l;
+      datap->known_groups = NULL;
+      datap->needed_groups = NULL;
+
+      retval = 1;
+    }
+  else
+    {
+      if (__builtin_expect (netgroup_resp.found == -1, 0))
+	{
+	  /* The daemon does not cache this database.  */
+	  __nss_not_use_nscd_netgroup = 1;
+	  goto out_close;
+	}
+
+      /* Set errno to 0 to indicate no error, just no found record.  */
+      __set_errno (0);
+      /* Even though we have not found anything, the result is zero.  */
+      retval = 0;
+    }
+
+ out_close:
+  if (sock != -1)
+    close_not_cancel_no_status (sock);
+ out:
+  if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
+    {
+      /* When we come here this means there has been a GC cycle while we
+	 were looking for the data.  This means the data might have been
+	 inconsistent.  Retry if possible.  */
+      if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
+	{
+	  /* nscd is just running gc now.  Disable using the mapping.  */
+	  if (atomic_decrement_val (&mapped->counter) == 0)
+	    __nscd_unmap (mapped);
+	  mapped = NO_MAPPING;
+	}
+
+      if (retval != -1)
+	goto retry;
+    }
+
+  return retval;
+}
+
+
+int
+__nscd_innetgr (const char *netgroup, const char *host, const char *user,
+		const char *domain)
+{
+  size_t key_len = (strlen (netgroup) + strlen (host ?: "")
+		    + strlen (user ?: "") + strlen (domain ?: "") + 7);
+  char *key;
+  bool use_alloca = __libc_use_alloca (key_len);
+  if (use_alloca)
+    key = alloca (key_len);
+  else
+    {
+      key = malloc (key_len);
+      if (key == NULL)
+	return -1;
+    }
+  char *wp = stpcpy (key, netgroup) + 1;
+  if (host != NULL)
+    {
+      *wp++ = '\1';
+      wp = stpcpy (wp, host) + 1;
+    }
+  else
+    *wp++ = '\0';
+  if (user != NULL)
+    {
+      *wp++ = '\1';
+      wp = stpcpy (wp, user) + 1;
+    }
+  else
+    *wp++ = '\0';
+  if (domain != NULL)
+    {
+      *wp++ = '\1';
+      wp = stpcpy (wp, domain) + 1;
+    }
+  else
+    *wp++ = '\0';
+  key_len = wp - key;
+
+  /* If the mapping is available, try to search there instead of
+     communicating with the nscd.  */
+  int gc_cycle;
+  int nretries = 0;
+  struct mapped_database *mapped;
+  mapped = __nscd_get_map_ref (GETFDNETGR, "netgroup", &map_handle, &gc_cycle);
+
+ retry:;
+  int retval = -1;
+  innetgroup_response_header innetgroup_resp;
+  int sock = -1;
+
+  if (mapped != NO_MAPPING)
+    {
+      struct datahead *found = __nscd_cache_search (INNETGR, key,
+						    key_len, mapped,
+						    sizeof innetgroup_resp);
+      if (found != NULL)
+	{
+	  innetgroup_resp = found->data[0].innetgroupdata;
+	  /* Now check if we can trust pw_resp fields.  If GC is
+	     in progress, it can contain anything.  */
+	  if (mapped->head->gc_cycle != gc_cycle)
+	    {
+	      retval = -2;
+	      goto out;
+	    }
+
+	  goto found_entry;
+	}
+    }
+
+  sock = __nscd_open_socket (key, key_len, INNETGR,
+			     &innetgroup_resp, sizeof (innetgroup_resp));
+  if (sock == -1)
+    {
+      /* nscd not running or wrong version.  */
+      __nss_not_use_nscd_netgroup = 1;
+      goto out;
+    }
+
+ found_entry:
+  if (innetgroup_resp.found == 1)
+    retval = innetgroup_resp.result;
+  else
+    {
+      if (__builtin_expect (innetgroup_resp.found == -1, 0))
+	{
+	  /* The daemon does not cache this database.  */
+	  __nss_not_use_nscd_netgroup = 1;
+	  goto out_close;
+	}
+
+      /* Set errno to 0 to indicate no error, just no found record.  */
+      __set_errno (0);
+      /* Even though we have not found anything, the result is zero.  */
+      retval = 0;
+    }
+
+ out_close:
+  if (sock != -1)
+    close_not_cancel_no_status (sock);
+ out:
+  if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
+    {
+      /* When we come here this means there has been a GC cycle while we
+	 were looking for the data.  This means the data might have been
+	 inconsistent.  Retry if possible.  */
+      if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
+	{
+	  /* nscd is just running gc now.  Disable using the mapping.  */
+	  if (atomic_decrement_val (&mapped->counter) == 0)
+	    __nscd_unmap (mapped);
+	  mapped = NO_MAPPING;
+	}
+
+      if (retval != -1)
+	goto retry;
+    }
+
+  if (! use_alloca)
+    free (key);
+
+  return retval;
+}