1 /* Copyright (C) 2007-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
21 #include <not-cancel.h>
25 #include "nscd-client.h"
26 #include "nscd_proto.h"
29 int __nss_not_use_nscd_services
;
32 static int nscd_getserv_r (const char *crit
, size_t critlen
, const char *proto
,
33 request_type type
, struct servent
*resultbuf
,
34 char *buf
, size_t buflen
, struct servent
**result
);
38 __nscd_getservbyname_r (const char *name
, const char *proto
,
39 struct servent
*result_buf
, char *buf
, size_t buflen
,
40 struct servent
**result
)
42 return nscd_getserv_r (name
, strlen (name
), proto
, GETSERVBYNAME
, result_buf
,
48 __nscd_getservbyport_r (int port
, const char *proto
,
49 struct servent
*result_buf
, char *buf
, size_t buflen
,
50 struct servent
**result
)
52 char portstr
[3 * sizeof (int) + 2];
53 portstr
[sizeof (portstr
) - 1] = '\0';
54 char *cp
= _itoa_word (port
, portstr
+ sizeof (portstr
) - 1, 10, 0);
56 return nscd_getserv_r (cp
, portstr
+ sizeof (portstr
) - 1 - cp
, proto
,
57 GETSERVBYPORT
, result_buf
, buf
, buflen
, result
);
61 libc_locked_map_ptr (, __serv_map_handle
) attribute_hidden
;
62 /* Note that we only free the structure if necessary. The memory
63 mapping is not removed since it is not visible to the malloc
66 __nscd_serv_map_freemem (void)
68 if (__serv_map_handle
.mapped
!= NO_MAPPING
)
70 void *p
= __serv_map_handle
.mapped
;
71 __serv_map_handle
.mapped
= NO_MAPPING
;
78 nscd_getserv_r (const char *crit
, size_t critlen
, const char *proto
,
79 request_type type
, struct servent
*resultbuf
,
80 char *buf
, size_t buflen
, struct servent
**result
)
84 size_t alloca_used
= 0;
86 /* If the mapping is available, try to search there instead of
87 communicating with the nscd. */
88 struct mapped_database
*mapped
;
89 mapped
= __nscd_get_map_ref (GETFDSERV
, "services", &__serv_map_handle
,
91 size_t protolen
= proto
== NULL
? 0 : strlen (proto
);
92 size_t keylen
= critlen
+ 1 + protolen
+ 1;
93 int alloca_key
= __libc_use_alloca (keylen
);
96 key
= alloca_account (keylen
, alloca_used
);
99 key
= malloc (keylen
);
103 memcpy (__mempcpy (__mempcpy (key
, crit
, critlen
),
104 "/", 1), proto
?: "", protolen
+ 1);
107 const char *s_name
= NULL
;
108 const char *s_proto
= NULL
;
109 int alloca_aliases_len
= 0;
110 const uint32_t *aliases_len
= NULL
;
111 const char *aliases_list
= NULL
;
113 const char *recend
= (const char *) ~UINTMAX_C (0);
115 serv_response_header serv_resp
;
117 if (mapped
!= NO_MAPPING
)
119 struct datahead
*found
= __nscd_cache_search (type
, key
, keylen
, mapped
,
124 s_name
= (char *) (&found
->data
[0].servdata
+ 1);
125 serv_resp
= found
->data
[0].servdata
;
126 s_proto
= s_name
+ serv_resp
.s_name_len
;
127 alloca_aliases_len
= 1;
128 aliases_len
= (uint32_t *) (s_proto
+ serv_resp
.s_proto_len
);
129 aliases_list
= ((char *) aliases_len
130 + serv_resp
.s_aliases_cnt
* sizeof (uint32_t));
131 recend
= (const char *) found
->data
+ found
->recsize
;
132 /* Now check if we can trust serv_resp fields. If GC is
133 in progress, it can contain anything. */
134 if (mapped
->head
->gc_cycle
!= gc_cycle
)
139 if (__builtin_expect ((const char *) aliases_len
140 + serv_resp
.s_aliases_cnt
* sizeof (uint32_t)
144 /* The aliases_len array in the mapped database might very
145 well be unaligned. We will access it word-wise so on
146 platforms which do not tolerate unaligned accesses we
147 need to make an aligned copy. */
148 if (((uintptr_t) aliases_len
& (__alignof__ (*aliases_len
) - 1))
153 = __libc_use_alloca (alloca_used
154 + (serv_resp
.s_aliases_cnt
155 * sizeof (uint32_t)));
156 if (alloca_aliases_len
)
157 tmp
= alloca_account (serv_resp
.s_aliases_cnt
162 tmp
= malloc (serv_resp
.s_aliases_cnt
* sizeof (uint32_t));
169 aliases_len
= memcpy (tmp
, aliases_len
,
170 serv_resp
.s_aliases_cnt
171 * sizeof (uint32_t));
178 sock
= __nscd_open_socket (key
, keylen
, type
, &serv_resp
,
182 __nss_not_use_nscd_services
= 1;
187 /* No value found so far. */
190 if (__glibc_unlikely (serv_resp
.found
== -1))
192 /* The daemon does not cache this database. */
193 __nss_not_use_nscd_services
= 1;
197 if (serv_resp
.found
== 1)
206 /* A first check whether the buffer is sufficiently large is possible. */
207 /* Now allocate the buffer the array for the group members. We must
208 align the pointer and the base of the h_addr_list pointers. */
209 align1
= ((__alignof__ (char *) - ((uintptr_t) cp
))
210 & (__alignof__ (char *) - 1));
211 align2
= ((__alignof__ (char *) - ((uintptr_t) (cp
+ align1
+ serv_resp
.s_name_len
212 + serv_resp
.s_proto_len
)))
213 & (__alignof__ (char *) - 1));
214 if (buflen
< (align1
+ serv_resp
.s_name_len
+ serv_resp
.s_proto_len
216 + (serv_resp
.s_aliases_cnt
+ 1) * sizeof (char *)))
219 __set_errno (ERANGE
);
225 /* Prepare the result as far as we can. */
226 resultbuf
->s_aliases
= (char **) cp
;
227 cp
+= (serv_resp
.s_aliases_cnt
+ 1) * sizeof (char *);
229 resultbuf
->s_name
= cp
;
230 cp
+= serv_resp
.s_name_len
;
231 resultbuf
->s_proto
= cp
;
232 cp
+= serv_resp
.s_proto_len
+ align2
;
233 resultbuf
->s_port
= serv_resp
.s_port
;
239 vec
[0].iov_base
= resultbuf
->s_name
;
240 vec
[0].iov_len
= serv_resp
.s_name_len
+ serv_resp
.s_proto_len
;
241 total_len
= vec
[0].iov_len
;
244 if (serv_resp
.s_aliases_cnt
> 0)
246 assert (alloca_aliases_len
== 0);
248 = __libc_use_alloca (alloca_used
249 + (serv_resp
.s_aliases_cnt
250 * sizeof (uint32_t)));
251 if (alloca_aliases_len
)
252 aliases_len
= alloca_account (serv_resp
.s_aliases_cnt
257 aliases_len
= malloc (serv_resp
.s_aliases_cnt
258 * sizeof (uint32_t));
259 if (aliases_len
== NULL
)
265 vec
[n
].iov_base
= (void *) aliases_len
;
266 vec
[n
].iov_len
= serv_resp
.s_aliases_cnt
* sizeof (uint32_t);
268 total_len
+= serv_resp
.s_aliases_cnt
* sizeof (uint32_t);
272 if ((size_t) __readvall (sock
, vec
, n
) != total_len
)
276 memcpy (resultbuf
->s_name
, s_name
,
277 serv_resp
.s_name_len
+ serv_resp
.s_proto_len
);
279 /* Now we also can read the aliases. */
281 for (cnt
= 0; cnt
< serv_resp
.s_aliases_cnt
; ++cnt
)
283 resultbuf
->s_aliases
[cnt
] = cp
;
284 cp
+= aliases_len
[cnt
];
285 total_len
+= aliases_len
[cnt
];
287 resultbuf
->s_aliases
[cnt
] = NULL
;
289 if (__builtin_expect ((const char *) aliases_list
+ total_len
> recend
,
292 /* aliases_len array might contain garbage during nscd GC cycle,
293 retry rather than fail in that case. */
294 if (aliases_list
!= NULL
&& mapped
->head
->gc_cycle
!= gc_cycle
)
299 /* See whether this would exceed the buffer capacity. */
300 if (__glibc_unlikely (cp
> buf
+ buflen
))
302 /* aliases_len array might contain garbage during nscd GC cycle,
303 retry rather than fail in that case. */
304 if (aliases_list
!= NULL
&& mapped
->head
->gc_cycle
!= gc_cycle
)
312 /* And finally read the aliases. */
313 if (aliases_list
== NULL
)
316 || ((size_t) __readall (sock
, resultbuf
->s_aliases
[0], total_len
)
325 memcpy (resultbuf
->s_aliases
[0], aliases_list
, total_len
);
327 /* Try to detect corrupt databases. */
328 if (resultbuf
->s_name
[serv_resp
.s_name_len
- 1] != '\0'
329 || resultbuf
->s_proto
[serv_resp
.s_proto_len
- 1] != '\0'
330 || ({for (cnt
= 0; cnt
< serv_resp
.s_aliases_cnt
; ++cnt
)
331 if (resultbuf
->s_aliases
[cnt
][aliases_len
[cnt
] - 1]
334 cnt
< serv_resp
.s_aliases_cnt
; }))
336 /* We cannot use the database. */
337 if (mapped
->head
->gc_cycle
!= gc_cycle
)
348 /* Set errno to 0 to indicate no error, just no found record. */
350 /* Even though we have not found anything, the result is zero. */
356 __close_nocancel_nostatus (sock
);
358 if (__nscd_drop_map_ref (mapped
, &gc_cycle
) != 0)
360 /* When we come here this means there has been a GC cycle while we
361 were looking for the data. This means the data might have been
362 inconsistent. Retry if possible. */
363 if ((gc_cycle
& 1) != 0 || ++nretries
== 5 || retval
== -1)
365 /* nscd is just running gc now. Disable using the mapping. */
366 if (atomic_fetch_add_relaxed (&mapped
->counter
, -1) == 1)
367 __nscd_unmap (mapped
);
373 if (!alloca_aliases_len
)
374 free ((void *) aliases_len
);
379 if (!alloca_aliases_len
)
380 free ((void *) aliases_len
);