resolv: Suppress maybe uninitialized warning
[glibc.git] / nscd / nscd_getgr_r.c
blobd9b91a470f0273709e57cdeae73d5af131046e7d
1 /* Copyright (C) 1998-2014 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 1998.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
19 #include <alloca.h>
20 #include <assert.h>
21 #include <errno.h>
22 #include <grp.h>
23 #include <stdint.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <unistd.h>
28 #include <sys/mman.h>
29 #include <sys/socket.h>
30 #include <sys/uio.h>
31 #include <sys/un.h>
32 #include <not-cancel.h>
33 #include <_itoa.h>
35 #include "nscd-client.h"
36 #include "nscd_proto.h"
38 int __nss_not_use_nscd_group;
40 static int nscd_getgr_r (const char *key, size_t keylen, request_type type,
41 struct group *resultbuf, char *buffer,
42 size_t buflen, struct group **result)
43 internal_function;
46 int
47 __nscd_getgrnam_r (const char *name, struct group *resultbuf, char *buffer,
48 size_t buflen, struct group **result)
50 return nscd_getgr_r (name, strlen (name) + 1, GETGRBYNAME, resultbuf,
51 buffer, buflen, result);
55 int
56 __nscd_getgrgid_r (gid_t gid, struct group *resultbuf, char *buffer,
57 size_t buflen, struct group **result)
59 char buf[3 * sizeof (gid_t)];
60 buf[sizeof (buf) - 1] = '\0';
61 char *cp = _itoa_word (gid, buf + sizeof (buf) - 1, 10, 0);
63 return nscd_getgr_r (cp, buf + sizeof (buf) - cp, GETGRBYGID, resultbuf,
64 buffer, buflen, result);
68 libc_locked_map_ptr (,__gr_map_handle) attribute_hidden;
69 /* Note that we only free the structure if necessary. The memory
70 mapping is not removed since it is not visible to the malloc
71 handling. */
72 libc_freeres_fn (gr_map_free)
74 if (__gr_map_handle.mapped != NO_MAPPING)
76 void *p = __gr_map_handle.mapped;
77 __gr_map_handle.mapped = NO_MAPPING;
78 free (p);
83 static int
84 internal_function
85 nscd_getgr_r (const char *key, size_t keylen, request_type type,
86 struct group *resultbuf, char *buffer, size_t buflen,
87 struct group **result)
89 int gc_cycle;
90 int nretries = 0;
91 const uint32_t *len = NULL;
92 size_t lensize = 0;
94 /* If the mapping is available, try to search there instead of
95 communicating with the nscd. */
96 struct mapped_database *mapped = __nscd_get_map_ref (GETFDGR, "group",
97 &__gr_map_handle,
98 &gc_cycle);
99 retry:;
100 const char *gr_name = NULL;
101 size_t gr_name_len = 0;
102 int retval = -1;
103 const char *recend = (const char *) ~UINTMAX_C (0);
104 gr_response_header gr_resp;
106 if (mapped != NO_MAPPING)
108 struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
109 sizeof gr_resp);
110 if (found != NULL)
112 len = (const uint32_t *) (&found->data[0].grdata + 1);
113 gr_resp = found->data[0].grdata;
114 gr_name = ((const char *) len
115 + gr_resp.gr_mem_cnt * sizeof (uint32_t));
116 gr_name_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
117 recend = (const char *) found->data + found->recsize;
118 /* Now check if we can trust gr_resp fields. If GC is
119 in progress, it can contain anything. */
120 if (mapped->head->gc_cycle != gc_cycle)
122 retval = -2;
123 goto out;
126 /* The alignment is always sufficient, unless GC is in progress. */
127 assert (((uintptr_t) len & (__alignof__ (*len) - 1)) == 0);
131 int sock = -1;
132 if (gr_name == NULL)
134 sock = __nscd_open_socket (key, keylen, type, &gr_resp,
135 sizeof (gr_resp));
136 if (sock == -1)
138 __nss_not_use_nscd_group = 1;
139 goto out;
143 /* No value found so far. */
144 *result = NULL;
146 if (__glibc_unlikely (gr_resp.found == -1))
148 /* The daemon does not cache this database. */
149 __nss_not_use_nscd_group = 1;
150 goto out_close;
153 if (gr_resp.found == 1)
155 struct iovec vec[2];
156 char *p = buffer;
157 size_t total_len;
158 uintptr_t align;
159 nscd_ssize_t cnt;
161 /* Now allocate the buffer the array for the group members. We must
162 align the pointer. */
163 align = ((__alignof__ (char *) - (p - ((char *) 0)))
164 & (__alignof__ (char *) - 1));
165 total_len = (align + (1 + gr_resp.gr_mem_cnt) * sizeof (char *)
166 + gr_resp.gr_name_len + gr_resp.gr_passwd_len);
167 if (__glibc_unlikely (buflen < total_len))
169 no_room:
170 __set_errno (ERANGE);
171 retval = ERANGE;
172 goto out_close;
174 buflen -= total_len;
176 p += align;
177 resultbuf->gr_mem = (char **) p;
178 p += (1 + gr_resp.gr_mem_cnt) * sizeof (char *);
180 /* Set pointers for strings. */
181 resultbuf->gr_name = p;
182 p += gr_resp.gr_name_len;
183 resultbuf->gr_passwd = p;
184 p += gr_resp.gr_passwd_len;
186 /* Fill in what we know now. */
187 resultbuf->gr_gid = gr_resp.gr_gid;
189 /* Read the length information, group name, and password. */
190 if (gr_name == NULL)
192 /* Handle a simple, usual case: no group members. */
193 if (__glibc_likely (gr_resp.gr_mem_cnt == 0))
195 size_t n = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
196 if (__builtin_expect (__readall (sock, resultbuf->gr_name, n)
197 != (ssize_t) n, 0))
198 goto out_close;
200 else
202 /* Allocate array to store lengths. */
203 if (lensize == 0)
205 lensize = gr_resp.gr_mem_cnt * sizeof (uint32_t);
206 len = (uint32_t *) alloca (lensize);
208 else if (gr_resp.gr_mem_cnt * sizeof (uint32_t) > lensize)
209 len = extend_alloca (len, lensize,
210 gr_resp.gr_mem_cnt * sizeof (uint32_t));
212 vec[0].iov_base = (void *) len;
213 vec[0].iov_len = gr_resp.gr_mem_cnt * sizeof (uint32_t);
214 vec[1].iov_base = resultbuf->gr_name;
215 vec[1].iov_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
216 total_len = vec[0].iov_len + vec[1].iov_len;
218 /* Get this data. */
219 size_t n = __readvall (sock, vec, 2);
220 if (__glibc_unlikely (n != total_len))
221 goto out_close;
224 else
225 /* We already have the data. Just copy the group name and
226 password. */
227 memcpy (resultbuf->gr_name, gr_name,
228 gr_resp.gr_name_len + gr_resp.gr_passwd_len);
230 /* Clear the terminating entry. */
231 resultbuf->gr_mem[gr_resp.gr_mem_cnt] = NULL;
233 /* Prepare reading the group members. */
234 total_len = 0;
235 for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
237 resultbuf->gr_mem[cnt] = p;
238 total_len += len[cnt];
239 p += len[cnt];
242 if (__glibc_unlikely (gr_name + gr_name_len + total_len > recend))
244 /* len array might contain garbage during nscd GC cycle,
245 retry rather than fail in that case. */
246 if (gr_name != NULL && mapped->head->gc_cycle != gc_cycle)
247 retval = -2;
248 goto out_close;
250 if (__glibc_unlikely (total_len > buflen))
252 /* len array might contain garbage during nscd GC cycle,
253 retry rather than fail in that case. */
254 if (gr_name != NULL && mapped->head->gc_cycle != gc_cycle)
256 retval = -2;
257 goto out_close;
259 else
260 goto no_room;
263 retval = 0;
265 /* If there are no group members TOTAL_LEN is zero. */
266 if (gr_name == NULL)
268 if (total_len > 0
269 && __builtin_expect (__readall (sock, resultbuf->gr_mem[0],
270 total_len) != total_len, 0))
272 /* The `errno' to some value != ERANGE. */
273 __set_errno (ENOENT);
274 retval = ENOENT;
276 else
277 *result = resultbuf;
279 else
281 /* Copy the group member names. */
282 memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
284 /* Try to detect corrupt databases. */
285 if (resultbuf->gr_name[gr_name_len - 1] != '\0'
286 || resultbuf->gr_passwd[gr_resp.gr_passwd_len - 1] != '\0'
287 || ({for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
288 if (resultbuf->gr_mem[cnt][len[cnt] - 1] != '\0')
289 break;
290 cnt < gr_resp.gr_mem_cnt; }))
292 /* We cannot use the database. */
293 retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1;
294 goto out_close;
297 *result = resultbuf;
300 else
302 /* Set errno to 0 to indicate no error, just no found record. */
303 __set_errno (0);
304 /* Even though we have not found anything, the result is zero. */
305 retval = 0;
308 out_close:
309 if (sock != -1)
310 close_not_cancel_no_status (sock);
311 out:
312 if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
314 /* When we come here this means there has been a GC cycle while we
315 were looking for the data. This means the data might have been
316 inconsistent. Retry if possible. */
317 if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
319 /* nscd is just running gc now. Disable using the mapping. */
320 if (atomic_decrement_val (&mapped->counter) == 0)
321 __nscd_unmap (mapped);
322 mapped = NO_MAPPING;
325 if (retval != -1)
326 goto retry;
329 return retval;