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 (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 (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   int gc_cycle;
  88   const uint32_t *len = NULL;
  89   size_t lensize = 0;
  90
  91   /* If the mapping is available, try to search there instead of
  92      communicating with the nscd.  */
  93   struct mapped_database *mapped = __nscd_get_map_ref (GETFDGR, "group",
  94                                                        &map_handle, &gc_cycle);
  95  retry:;
  96   const gr_response_header *gr_resp = NULL;
  97   const char *gr_name = NULL;
  98   size_t gr_name_len = 0;
  99   int retval = -1;
 100   const char *recend = (const char *) ~UINTMAX_C (0);
 101
 102   if (mapped != NO_MAPPING)
 103     {
 104       const struct datahead *found = __nscd_cache_search (type, key, keylen,
 105                                                           mapped);
 106       if (found != NULL)
 107         {
 108           gr_resp = &found->data[0].grdata;
 109           len = (const uint32_t *) (gr_resp + 1);
 110           /* The alignment is always sufficient.  */
 111           assert (((uintptr_t) len & (__alignof__ (*len) - 1)) == 0);
 112           gr_name = ((const char *) len
 113                      + gr_resp->gr_mem_cnt * sizeof (uint32_t));
 114           gr_name_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 115           recend = (const char *) found->data + found->recsize;
 116         }
 117     }
 118
 119   gr_response_header gr_resp_mem;
 120   int sock = -1;
 121   if (gr_resp == NULL)
 122     {
 123       sock = __nscd_open_socket (key, keylen, type, &gr_resp_mem,
 124                                  sizeof (gr_resp_mem));
 125       if (sock == -1)
 126         {
 127           __nss_not_use_nscd_group = 1;
 128           goto out;
 129         }
 130
 131       gr_resp = &gr_resp_mem;
 132     }
 133
 134   /* No value found so far.  */
 135   *result = NULL;
 136
 137   if (__builtin_expect (gr_resp->found == -1, 0))
 138     {
 139       /* The daemon does not cache this database.  */
 140       __nss_not_use_nscd_group = 1;
 141       goto out_close;
 142     }
 143
 144   if (gr_resp->found == 1)
 145     {
 146       struct iovec vec[2];
 147       char *p = buffer;
 148       size_t total_len;
 149       uintptr_t align;
 150       nscd_ssize_t cnt;
 151
 152       /* Now allocate the buffer the array for the group members.  We must
 153          align the pointer.  */
 154       align = ((__alignof__ (char *) - (p - ((char *) 0)))
 155                & (__alignof__ (char *) - 1));
 156       total_len = (align + (1 + gr_resp->gr_mem_cnt) * sizeof (char *)
 157                    + gr_resp->gr_name_len + gr_resp->gr_passwd_len);
 158       if (__builtin_expect (buflen < total_len, 0))
 159         {
 160         no_room:
 161           __set_errno (ERANGE);
 162           retval = ERANGE;
 163           goto out_close;
 164         }
 165       buflen -= total_len;
 166
 167       p += align;
 168       resultbuf->gr_mem = (char **) p;
 169       p += (1 + gr_resp->gr_mem_cnt) * sizeof (char *);
 170
 171       /* Set pointers for strings.  */
 172       resultbuf->gr_name = p;
 173       p += gr_resp->gr_name_len;
 174       resultbuf->gr_passwd = p;
 175       p += gr_resp->gr_passwd_len;
 176
 177       /* Fill in what we know now.  */
 178       resultbuf->gr_gid = gr_resp->gr_gid;
 179
 180       /* Read the length information, group name, and password.  */
 181       if (gr_name == NULL)
 182         {
 183           /* Allocate array to store lengths.  */
 184           if (lensize == 0)
 185             {
 186               lensize = gr_resp->gr_mem_cnt * sizeof (uint32_t);
 187               len = (uint32_t *) alloca (lensize);
 188             }
 189           else if (gr_resp->gr_mem_cnt * sizeof (uint32_t) > lensize)
 190             len = extend_alloca (len, lensize,
 191                                  gr_resp->gr_mem_cnt * sizeof (uint32_t));
 192
 193           vec[0].iov_base = (void *) len;
 194           vec[0].iov_len = gr_resp->gr_mem_cnt * sizeof (uint32_t);
 195           vec[1].iov_base = resultbuf->gr_name;
 196           vec[1].iov_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 197           total_len = vec[0].iov_len + vec[1].iov_len;
 198
 199           /* Get this data.  */
 200           size_t n = TEMP_FAILURE_RETRY (__readv (sock, vec, 2));
 201           if (__builtin_expect (n != total_len, 0))
 202             goto out_close;
 203         }
 204       else
 205         /* We already have the data.  Just copy the group name and
 206            password.  */
 207         memcpy (resultbuf->gr_name, gr_name, gr_name_len);
 208
 209       /* Clear the terminating entry.  */
 210       resultbuf->gr_mem[gr_resp->gr_mem_cnt] = NULL;
 211
 212       /* Prepare reading the group members.  */
 213       total_len = 0;
 214       for (cnt = 0; cnt < gr_resp->gr_mem_cnt; ++cnt)
 215         {
 216           resultbuf->gr_mem[cnt] = p;
 217           total_len += len[cnt];
 218           p += len[cnt];
 219         }
 220
 221       if (__builtin_expect (gr_name + gr_name_len + total_len > recend, 0))
 222         goto out_close;
 223       if (__builtin_expect (total_len > buflen, 0))
 224         goto no_room;
 225
 226       retval = 0;
 227       if (gr_name == NULL)
 228         {
 229           size_t n = TEMP_FAILURE_RETRY (__read (sock, resultbuf->gr_mem[0],
 230                                                  total_len));
 231           if (__builtin_expect (n != total_len, 0))
 232             {
 233               /* The `errno' to some value != ERANGE.  */
 234               __set_errno (ENOENT);
 235               retval = ENOENT;
 236             }
 237           else
 238             *result = resultbuf;
 239         }
 240       else
 241         {
 242           /* Copy the group member names.  */
 243           memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
 244
 245           *result = resultbuf;
 246         }
 247     }
 248   else
 249     {
 250       /* The `errno' to some value != ERANGE.  */
 251       __set_errno (ENOENT);
 252       /* Even though we have not found anything, the result is zero.  */
 253       retval = 0;
 254     }
 255
 256  out_close:
 257   if (sock != -1)
 258     close_not_cancel_no_status (sock);
 259  out:
 260   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0 && retval != -1)
 261     {
 262       /* When we come here this means there has been a GC cycle while we
 263          were looking for the data.  This means the data might have been
 264          inconsistent.  Retry if possible.  */
 265       if ((gc_cycle & 1) != 0)
 266         {
 267           /* nscd is just running gc now.  Disable using the mapping.  */
 268           __nscd_unmap (mapped);
 269           mapped = NO_MAPPING;
 270         }
 271
 272       goto retry;
 273     }
 274
 275   return retval;
 276 }