nscd/nscd_getgr_r.c

   1 /* Copyright (C) 1998, 1999, 2000, 2002, 2003, 2004
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 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 Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the 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    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <alloca.h>
  22 #include <assert.h>
  23 #include <errno.h>
  24 #include <grp.h>
  25 #include <stdint.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30 #include <sys/mman.h>
  31 #include <sys/socket.h>
  32 #include <sys/uio.h>
  33 #include <sys/un.h>
  34 #include <not-cancel.h>
  35 #include <stdio-common/_itoa.h>
  36
  37 #include "nscd-client.h"
  38 #include "nscd_proto.h"
  39
  40 int __nss_not_use_nscd_group;
  41
  42 static int nscd_getgr_r (const char *key, size_t keylen, request_type type,
  43                          struct group *resultbuf, char *buffer,
  44                          size_t buflen, struct group **result)
  45      internal_function;
  46
  47
  48 int
  49 __nscd_getgrnam_r (const char *name, struct group *resultbuf, char *buffer,
  50                    size_t buflen, struct group **result)
  51 {
  52   return nscd_getgr_r (name, strlen (name) + 1, GETGRBYNAME, resultbuf,
  53                        buffer, buflen, result);
  54 }
  55
  56
  57 int
  58 __nscd_getgrgid_r (gid_t gid, struct group *resultbuf, char *buffer,
  59                    size_t buflen, struct group **result)
  60 {
  61   char buf[3 * sizeof (gid_t)];
  62   buf[sizeof (buf) - 1] = '\0';
  63   char *cp = _itoa_word (gid, buf + sizeof (buf) - 1, 10, 0);
  64
  65   return nscd_getgr_r (cp, buf + sizeof (buf) - cp, GETGRBYGID, resultbuf,
  66                        buffer, buflen, result);
  67 }
  68
  69
  70 libc_locked_map_ptr (,__gr_map_handle);
  71 /* Note that we only free the structure if necessary.  The memory
  72    mapping is not removed since it is not visible to the malloc
  73    handling.  */
  74 libc_freeres_fn (gr_map_free)
  75 {
  76   if (__gr_map_handle.mapped != NO_MAPPING)
  77     {
  78       void *p = __gr_map_handle.mapped;
  79       __gr_map_handle.mapped = NO_MAPPING;
  80       free (p);
  81     }
  82 }
  83
  84
  85 static int
  86 internal_function
  87 nscd_getgr_r (const char *key, size_t keylen, request_type type,
  88               struct group *resultbuf, char *buffer, size_t buflen,
  89               struct group **result)
  90 {
  91   int gc_cycle;
  92   const uint32_t *len = NULL;
  93   size_t lensize = 0;
  94
  95   /* If the mapping is available, try to search there instead of
  96      communicating with the nscd.  */
  97   struct mapped_database *mapped = __nscd_get_map_ref (GETFDGR, "group",
  98                                                        &__gr_map_handle,
  99                                                        &gc_cycle);
 100  retry:;
 101   const gr_response_header *gr_resp = NULL;
 102   const char *gr_name = NULL;
 103   size_t gr_name_len = 0;
 104   int retval = -1;
 105   const char *recend = (const char *) ~UINTMAX_C (0);
 106
 107   if (mapped != NO_MAPPING)
 108     {
 109       const struct datahead *found = __nscd_cache_search (type, key, keylen,
 110                                                           mapped);
 111       if (found != NULL)
 112         {
 113           gr_resp = &found->data[0].grdata;
 114           len = (const uint32_t *) (gr_resp + 1);
 115           /* The alignment is always sufficient.  */
 116           assert (((uintptr_t) len & (__alignof__ (*len) - 1)) == 0);
 117           gr_name = ((const char *) len
 118                      + gr_resp->gr_mem_cnt * sizeof (uint32_t));
 119           gr_name_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 120           recend = (const char *) found->data + found->recsize;
 121         }
 122     }
 123
 124   gr_response_header gr_resp_mem;
 125   int sock = -1;
 126   if (gr_resp == NULL)
 127     {
 128       sock = __nscd_open_socket (key, keylen, type, &gr_resp_mem,
 129                                  sizeof (gr_resp_mem));
 130       if (sock == -1)
 131         {
 132           __nss_not_use_nscd_group = 1;
 133           goto out;
 134         }
 135
 136       gr_resp = &gr_resp_mem;
 137     }
 138
 139   /* No value found so far.  */
 140   *result = NULL;
 141
 142   if (__builtin_expect (gr_resp->found == -1, 0))
 143     {
 144       /* The daemon does not cache this database.  */
 145       __nss_not_use_nscd_group = 1;
 146       goto out_close;
 147     }
 148
 149   if (gr_resp->found == 1)
 150     {
 151       struct iovec vec[2];
 152       char *p = buffer;
 153       size_t total_len;
 154       uintptr_t align;
 155       nscd_ssize_t cnt;
 156
 157       /* Now allocate the buffer the array for the group members.  We must
 158          align the pointer.  */
 159       align = ((__alignof__ (char *) - (p - ((char *) 0)))
 160                & (__alignof__ (char *) - 1));
 161       total_len = (align + (1 + gr_resp->gr_mem_cnt) * sizeof (char *)
 162                    + gr_resp->gr_name_len + gr_resp->gr_passwd_len);
 163       if (__builtin_expect (buflen < total_len, 0))
 164         {
 165         no_room:
 166           __set_errno (ERANGE);
 167           retval = ERANGE;
 168           goto out_close;
 169         }
 170       buflen -= total_len;
 171
 172       p += align;
 173       resultbuf->gr_mem = (char **) p;
 174       p += (1 + gr_resp->gr_mem_cnt) * sizeof (char *);
 175
 176       /* Set pointers for strings.  */
 177       resultbuf->gr_name = p;
 178       p += gr_resp->gr_name_len;
 179       resultbuf->gr_passwd = p;
 180       p += gr_resp->gr_passwd_len;
 181
 182       /* Fill in what we know now.  */
 183       resultbuf->gr_gid = gr_resp->gr_gid;
 184
 185       /* Read the length information, group name, and password.  */
 186       if (gr_name == NULL)
 187         {
 188           /* Allocate array to store lengths.  */
 189           if (lensize == 0)
 190             {
 191               lensize = gr_resp->gr_mem_cnt * sizeof (uint32_t);
 192               len = (uint32_t *) alloca (lensize);
 193             }
 194           else if (gr_resp->gr_mem_cnt * sizeof (uint32_t) > lensize)
 195             len = extend_alloca (len, lensize,
 196                                  gr_resp->gr_mem_cnt * sizeof (uint32_t));
 197
 198           vec[0].iov_base = (void *) len;
 199           vec[0].iov_len = gr_resp->gr_mem_cnt * sizeof (uint32_t);
 200           vec[1].iov_base = resultbuf->gr_name;
 201           vec[1].iov_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 202           total_len = vec[0].iov_len + vec[1].iov_len;
 203
 204           /* Get this data.  */
 205           size_t n = TEMP_FAILURE_RETRY (__readv (sock, vec, 2));
 206           if (__builtin_expect (n != total_len, 0))
 207             goto out_close;
 208         }
 209       else
 210         /* We already have the data.  Just copy the group name and
 211            password.  */
 212         memcpy (resultbuf->gr_name, gr_name,
 213                 gr_resp->gr_name_len + gr_resp->gr_passwd_len);
 214
 215       /* Clear the terminating entry.  */
 216       resultbuf->gr_mem[gr_resp->gr_mem_cnt] = NULL;
 217
 218       /* Prepare reading the group members.  */
 219       total_len = 0;
 220       for (cnt = 0; cnt < gr_resp->gr_mem_cnt; ++cnt)
 221         {
 222           resultbuf->gr_mem[cnt] = p;
 223           total_len += len[cnt];
 224           p += len[cnt];
 225         }
 226
 227       if (__builtin_expect (gr_name + gr_name_len + total_len > recend, 0))
 228         goto out_close;
 229       if (__builtin_expect (total_len > buflen, 0))
 230         goto no_room;
 231
 232       retval = 0;
 233       if (gr_name == NULL)
 234         {
 235           size_t n = TEMP_FAILURE_RETRY (__read (sock, resultbuf->gr_mem[0],
 236                                                  total_len));
 237           if (__builtin_expect (n != total_len, 0))
 238             {
 239               /* The `errno' to some value != ERANGE.  */
 240               __set_errno (ENOENT);
 241               retval = ENOENT;
 242             }
 243           else
 244             *result = resultbuf;
 245         }
 246       else
 247         {
 248           /* Copy the group member names.  */
 249           memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
 250
 251           /* Try to detect corrupt databases.  */
 252           if (resultbuf->gr_name[gr_name_len - 1] != '\0'
 253               || resultbuf->gr_passwd[gr_resp->gr_passwd_len - 1] != '\0'
 254               || ({for (cnt = 0; cnt < gr_resp->gr_mem_cnt; ++cnt)
 255                      if (resultbuf->gr_mem[cnt][len[cnt] - 1] != '\0')
 256                        break;
 257                    cnt < gr_resp->gr_mem_cnt; }))
 258             {
 259               /* We cannot use the database.  */
 260               retval = -1;
 261               goto out_close;
 262             }
 263
 264           *result = resultbuf;
 265         }
 266     }
 267   else
 268     {
 269       /* The `errno' to some value != ERANGE.  */
 270       __set_errno (ENOENT);
 271       /* Even though we have not found anything, the result is zero.  */
 272       retval = 0;
 273     }
 274
 275  out_close:
 276   if (sock != -1)
 277     close_not_cancel_no_status (sock);
 278  out:
 279   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0 && retval != -1)
 280     {
 281       /* When we come here this means there has been a GC cycle while we
 282          were looking for the data.  This means the data might have been
 283          inconsistent.  Retry if possible.  */
 284       if ((gc_cycle & 1) != 0)
 285         {
 286           /* nscd is just running gc now.  Disable using the mapping.  */
 287           __nscd_unmap (mapped);
 288           mapped = NO_MAPPING;
 289         }
 290
 291       goto retry;
 292     }
 293
 294   return retval;
 295 }