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 <assert.h>
  22 #include <errno.h>
  23 #include <grp.h>
  24 #include <stdint.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <sys/mman.h>
  30 #include <sys/socket.h>
  31 #include <sys/uio.h>
  32 #include <sys/un.h>
  33 #include <not-cancel.h>
  34 #include <stdio-common/_itoa.h>
  35
  36 #include "nscd-client.h"
  37 #include "nscd_proto.h"
  38
  39 int __nss_not_use_nscd_group;
  40
  41 static int nscd_getgr_r (const char *key, size_t keylen, request_type type,
  42                          struct group *resultbuf, char *buffer,
  43                          size_t buflen, struct group **result)
  44      internal_function;
  45
  46
  47 int
  48 __nscd_getgrnam_r (const char *name, struct group *resultbuf, char *buffer,
  49                    size_t buflen, struct group **result)
  50 {
  51   return nscd_getgr_r (name, strlen (name) + 1, GETGRBYNAME, resultbuf,
  52                        buffer, buflen, result);
  53 }
  54
  55
  56 int
  57 __nscd_getgrgid_r (gid_t gid, struct group *resultbuf, char *buffer,
  58                    size_t buflen, struct group **result)
  59 {
  60   char buf[3 * sizeof (gid_t)];
  61   buf[sizeof (buf) - 1] = '\0';
  62   char *cp = _itoa_word (gid, buf + sizeof (buf) - 1, 10, 0);
  63
  64   return nscd_getgr_r (cp, buf + sizeof (buf) - cp, GETGRBYGID, resultbuf,
  65                        buffer, buflen, result);
  66 }
  67
  68
  69 libc_locked_map_ptr (map_handle);
  70 /* Note that we only free the structure if necessary.  The memory
  71    mapping is not removed since it is not visible to the malloc
  72    handling.  */
  73 libc_freeres_fn (gr_map_free)
  74 {
  75
  76   if (map_handle.mapped != NO_MAPPING)
  77     free (map_handle.mapped);
  78 }
  79
  80
  81 static int
  82 internal_function
  83 nscd_getgr_r (const char *key, size_t keylen, request_type type,
  84               struct group *resultbuf, char *buffer, size_t buflen,
  85               struct group **result)
  86 {
  87   const gr_response_header *gr_resp = NULL;
  88   const uint32_t *len = NULL;
  89   const char *gr_name = NULL;
  90   size_t gr_name_len = 0;
  91   int retval = -1;
  92   int gc_cycle;
  93   const char *recend = (const char *) ~UINTMAX_C (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                                                        &map_handle, &gc_cycle);
  99  retry:
 100   if (mapped != NO_MAPPING)
 101     {
 102       const struct datahead *found = __nscd_cache_search (type, key, keylen,
 103                                                           mapped);
 104       if (found != NULL)
 105         {
 106           gr_resp = &found->data[0].grdata;
 107           len = (const uint32_t *) (gr_resp + 1);
 108           /* The alignment is always sufficient.  */
 109           assert (((uintptr_t) len & (__alignof__ (*len) - 1)) == 0);
 110           gr_name = ((const char *) len
 111                      + gr_resp->gr_mem_cnt * sizeof (uint32_t));
 112           gr_name_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 113           recend = (const char *) found->data + found->recsize;
 114         }
 115     }
 116
 117   gr_response_header gr_resp_mem;
 118   int sock = -1;
 119   if (gr_resp == NULL)
 120     {
 121       sock = __nscd_open_socket (key, keylen, type, &gr_resp_mem,
 122                                  sizeof (gr_resp_mem));
 123       if (sock == -1)
 124         {
 125           __nss_not_use_nscd_group = 1;
 126           goto out;
 127         }
 128
 129       gr_resp = &gr_resp_mem;
 130     }
 131
 132   /* No value found so far.  */
 133   *result = NULL;
 134
 135   if (__builtin_expect (gr_resp->found == -1, 0))
 136     {
 137       /* The daemon does not cache this database.  */
 138       __nss_not_use_nscd_group = 1;
 139       goto out_close;
 140     }
 141
 142   if (gr_resp->found == 1)
 143     {
 144       struct iovec vec[2];
 145       char *p = buffer;
 146       size_t total_len;
 147       uintptr_t align;
 148       nscd_ssize_t cnt;
 149
 150       /* Now allocate the buffer the array for the group members.  We must
 151          align the pointer.  */
 152       align = ((__alignof__ (char *) - (p - ((char *) 0)))
 153                & (__alignof__ (char *) - 1));
 154       total_len = (align + (1 + gr_resp->gr_mem_cnt) * sizeof (char *)
 155                    + gr_resp->gr_name_len + gr_resp->gr_passwd_len);
 156       if (__builtin_expect (buflen < total_len, 0))
 157         {
 158         no_room:
 159           __set_errno (ERANGE);
 160           retval = ERANGE;
 161           goto out_close;
 162         }
 163       buflen -= total_len;
 164
 165       p += align;
 166       resultbuf->gr_mem = (char **) p;
 167       p += (1 + gr_resp->gr_mem_cnt) * sizeof (char *);
 168
 169       /* Set pointers for strings.  */
 170       resultbuf->gr_name = p;
 171       p += gr_resp->gr_name_len;
 172       resultbuf->gr_passwd = p;
 173       p += gr_resp->gr_passwd_len;
 174
 175       /* Fill in what we know now.  */
 176       resultbuf->gr_gid = gr_resp->gr_gid;
 177
 178       /* Read the length information, group name, and password.  */
 179       if (len == NULL)
 180         {
 181           /* Allocate array to store lengths.  */
 182           len = (uint32_t *) alloca (gr_resp->gr_mem_cnt * sizeof (uint32_t));
 183
 184           vec[0].iov_base = (void *) len;
 185           vec[0].iov_len = gr_resp->gr_mem_cnt * sizeof (uint32_t);
 186           vec[1].iov_base = resultbuf->gr_name;
 187           vec[1].iov_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 188           total_len = vec[0].iov_len + vec[1].iov_len;
 189
 190           /* Get this data.  */
 191           size_t n = TEMP_FAILURE_RETRY (__readv (sock, vec, 2));
 192           if (__builtin_expect (n != total_len, 0))
 193             goto out_close;
 194         }
 195       else
 196         /* We already have the data.  Just copy the group name and
 197            password.  */
 198         memcpy (resultbuf->gr_name, gr_name, gr_name_len);
 199
 200       /* Clear the terminating entry.  */
 201       resultbuf->gr_mem[gr_resp->gr_mem_cnt] = NULL;
 202
 203       /* Prepare reading the group members.  */
 204       total_len = 0;
 205       for (cnt = 0; cnt < gr_resp->gr_mem_cnt; ++cnt)
 206         {
 207           resultbuf->gr_mem[cnt] = p;
 208           total_len += len[cnt];
 209           p += len[cnt];
 210         }
 211
 212       if (__builtin_expect (gr_name + gr_name_len + total_len > recend, 0))
 213         goto out_close;
 214       if (__builtin_expect (total_len > buflen, 0))
 215         goto no_room;
 216
 217       retval = 0;
 218       if (gr_name == NULL)
 219         {
 220           size_t n = TEMP_FAILURE_RETRY (__read (sock, resultbuf->gr_mem[0],
 221                                                  total_len));
 222           if (__builtin_expect (n != total_len, 0))
 223             {
 224               /* The `errno' to some value != ERANGE.  */
 225               __set_errno (ENOENT);
 226               retval = ENOENT;
 227             }
 228           else
 229             *result = resultbuf;
 230         }
 231       else
 232         {
 233           /* Copy the group member names.  */
 234           memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
 235
 236           *result = resultbuf;
 237         }
 238     }
 239   else
 240     {
 241       /* The `errno' to some value != ERANGE.  */
 242       __set_errno (ENOENT);
 243       /* Even though we have not found anything, the result is zero.  */
 244       retval = 0;
 245     }
 246
 247  out_close:
 248   if (sock != -1)
 249     close_not_cancel_no_status (sock);
 250  out:
 251   if (__nscd_drop_map_ref (mapped, gc_cycle) != 0)
 252     /* When we come here this means there has been a GC cycle while we
 253        were looking for the data.  This means the data might have been
 254        inconsistent.  Retry.  */
 255     goto retry;
 256
 257   return retval;
 258 }