nscd/grpcache.c

   1 /* Cache handling for group lookup.
   2    Copyright (C) 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <assert.h>
  22 #include <errno.h>
  23 #include <error.h>
  24 #include <grp.h>
  25 #include <stddef.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30
  31 #include "nscd.h"
  32 #include "dbg_log.h"
  33
  34 /* This is the standard reply in case the service is disabled.  */
  35 static const gr_response_header disabled =
  36 {
  37   version: NSCD_VERSION,
  38   found: -1,
  39   gr_name_len: 0,
  40   gr_passwd_len: 0,
  41   gr_gid: -1,
  42   gr_mem_cnt: 0,
  43 };
  44
  45 /* This is the struct describing how to write this record.  */
  46 const struct iovec grp_iov_disabled =
  47 {
  48   iov_base: (void *) &disabled,
  49   iov_len: sizeof (disabled)
  50 };
  51
  52
  53 /* This is the standard reply in case we haven't found the dataset.  */
  54 static const gr_response_header notfound =
  55 {
  56   version: NSCD_VERSION,
  57   found: 0,
  58   gr_name_len: 0,
  59   gr_passwd_len: 0,
  60   gr_gid: -1,
  61   gr_mem_cnt: 0,
  62 };
  63
  64 /* This is the struct describing how to write this record.  */
  65 static const struct iovec iov_notfound =
  66 {
  67   iov_base: (void *) &notfound,
  68   iov_len: sizeof (notfound)
  69 };
  70
  71
  72 struct groupdata
  73 {
  74   gr_response_header resp;
  75   char strdata[0];
  76 };
  77
  78
  79 static void
  80 cache_addgr (struct database *db, int fd, request_header *req, void *key,
  81              struct group *grp)
  82 {
  83   ssize_t total;
  84   ssize_t written;
  85   time_t t = time (NULL);
  86
  87   if (grp == NULL)
  88     {
  89       /* We have no data.  This means we send the standard reply for this
  90          case.  */
  91       void *copy;
  92
  93       total = sizeof (notfound);
  94
  95       written = writev (fd, &iov_notfound, 1);
  96
  97       copy = malloc (req->key_len);
  98       if (copy == NULL)
  99         error (EXIT_FAILURE, errno, _("while allocating key copy"));
 100       memcpy (copy, key, req->key_len);
 101
 102       /* Compute the timeout time.  */
 103       t += db->negtimeout;
 104
 105       /* Now get the lock to safely insert the records.  */
 106       pthread_rwlock_rdlock (&db->lock);
 107
 108       cache_add (req->type, copy, req->key_len, &iov_notfound,
 109                  sizeof (notfound), (void *) -1, 0, t, db);
 110
 111       pthread_rwlock_unlock (&db->lock);
 112     }
 113   else
 114     {
 115       /* Determine the I/O structure.  */
 116       struct groupdata *data;
 117       size_t gr_name_len = strlen (grp->gr_name) + 1;
 118       size_t gr_passwd_len = strlen (grp->gr_passwd) + 1;
 119       size_t gr_mem_cnt = 0;
 120       size_t *gr_mem_len;
 121       size_t gr_mem_len_total = 0;
 122       char *gr_name;
 123       char *cp;
 124       char buf[12];
 125       ssize_t n;
 126       size_t cnt;
 127
 128       /* We need this to insert the `bygid' entry.  */
 129       n = snprintf (buf, sizeof (buf), "%d", grp->gr_gid) + 1;
 130
 131       /* Determine the length of all members.  */
 132       while (grp->gr_mem[gr_mem_cnt])
 133         ++gr_mem_cnt;
 134       gr_mem_len = (size_t *) alloca (gr_mem_cnt * sizeof (size_t));
 135       for (gr_mem_cnt = 0; grp->gr_mem[gr_mem_cnt]; ++gr_mem_cnt)
 136         {
 137           gr_mem_len[gr_mem_cnt] = strlen (grp->gr_mem[gr_mem_cnt]) + 1;
 138           gr_mem_len_total += gr_mem_len[gr_mem_cnt];
 139         }
 140
 141       /* We allocate all data in one memory block: the iov vector,
 142          the response header and the dataset itself.  */
 143       total = (sizeof (struct groupdata)
 144                + gr_mem_cnt * sizeof (size_t)
 145                + gr_name_len + gr_passwd_len + gr_mem_len_total);
 146       data = (struct groupdata *) malloc (total + n);
 147       if (data == NULL)
 148         /* There is no reason to go on.  */
 149         error (EXIT_FAILURE, errno, _("while allocating cache entry"));
 150
 151       data->resp.found = 1;
 152       data->resp.gr_name_len = gr_name_len;
 153       data->resp.gr_passwd_len = gr_passwd_len;
 154       data->resp.gr_gid = grp->gr_gid;
 155       data->resp.gr_mem_cnt = gr_mem_cnt;
 156
 157       cp = data->strdata;
 158
 159       /* This is the member string length array.  */
 160       cp = mempcpy (cp, gr_mem_len, gr_mem_cnt * sizeof (size_t));
 161       gr_name = cp = mempcpy (cp, grp->gr_name, gr_name_len);
 162       cp = mempcpy (cp, grp->gr_passwd, gr_passwd_len);
 163
 164       for (cnt = 0; cnt < gr_mem_cnt; ++cnt)
 165         cp = mempcpy (cp, grp->gr_mem[cnt], gr_mem_len[cnt]);
 166
 167       /* Finally the stringified GID value.  */
 168       memcpy (cp, buf, n);
 169
 170       /* Write the result.  */
 171       written = write (fd, &data->resp, total);
 172
 173       /* Compute the timeout time.  */
 174       t += db->postimeout;
 175
 176       /* Now get the lock to safely insert the records.  */
 177       pthread_rwlock_rdlock (&db->lock);
 178
 179       /* We have to add the value for both, byname and byuid.  */
 180       cache_add (GETGRBYNAME, gr_name, gr_name_len, data,
 181                  total, data, 0, t, db);
 182
 183       cache_add (GETGRBYGID, cp, n, data, total, data, 1, t, db);
 184
 185       pthread_rwlock_unlock (&db->lock);
 186     }
 187
 188   if (written != total)
 189     {
 190       char buf[256];
 191       dbg_log (_("short write in %s: %s"),  __FUNCTION__,
 192                strerror_r (errno, buf, sizeof (buf)));
 193     }
 194 }
 195
 196
 197 void
 198 addgrbyname (struct database *db, int fd, request_header *req, void *key)
 199 {
 200   /* Search for the entry matching the key.  Please note that we don't
 201      look again in the table whether the dataset is now available.  We
 202      simply insert it.  It does not matter if it is in there twice.  The
 203      pruning function only will look at the timestamp.  */
 204   int buflen = 256;
 205   char *buffer = alloca (buflen);
 206   struct group resultbuf;
 207   struct group *grp;
 208
 209   if (debug_level > 0)
 210     dbg_log (_("Haven't found \"%s\" in group cache!"), key);
 211
 212   while (getgrnam_r (key, &resultbuf, buffer, buflen, &grp) != 0
 213          && errno == ERANGE)
 214     {
 215       errno = 0;
 216       buflen += 256;
 217       buffer = alloca (buflen);
 218     }
 219
 220   cache_addgr (db, fd, req, key, grp);
 221 }
 222
 223
 224 void
 225 addgrbygid (struct database *db, int fd, request_header *req, void *key)
 226 {
 227   /* Search for the entry matching the key.  Please note that we don't
 228      look again in the table whether the dataset is now available.  We
 229      simply insert it.  It does not matter if it is in there twice.  The
 230      pruning function only will look at the timestamp.  */
 231   int buflen = 256;
 232   char *buffer = alloca (buflen);
 233   struct group resultbuf;
 234   struct group *grp;
 235   gid_t gid = atol (key);
 236
 237   if (debug_level > 0)
 238     dbg_log (_("Haven't found \"%d\" in group cache!"), gid);
 239
 240   while (getgrgid_r (gid, &resultbuf, buffer, buflen, &grp) != 0
 241          && errno == ERANGE)
 242     {
 243       errno = 0;
 244       buflen += 256;
 245       buffer = alloca (buflen);
 246     }
 247
 248   cache_addgr (db, fd, req, key, grp);
 249 }