1 | /* Copyright (C) 1996-2016 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. |
4 | |
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. |
9 | |
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. |
14 | |
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/>. */ |
18 | |
19 | #include <assert.h> |
20 | #include <atomic.h> |
21 | #include <errno.h> |
22 | #include <stdbool.h> |
23 | #include "nsswitch.h" |
24 | #include "sysdep.h" |
25 | #ifdef USE_NSCD |
26 | # include <nscd/nscd_proto.h> |
27 | #endif |
28 | #ifdef NEED__RES_HCONF |
29 | # include <resolv/res_hconf.h> |
30 | #endif |
31 | #ifdef NEED__RES |
32 | # include <resolv.h> |
33 | #endif |
34 | /*******************************************************************\ |
35 | |* Here we assume several symbols to be defined: *| |
36 | |* *| |
37 | |* LOOKUP_TYPE - the return type of the function *| |
38 | |* *| |
39 | |* FUNCTION_NAME - name of the non-reentrant function *| |
40 | |* *| |
41 | |* DATABASE_NAME - name of the database the function accesses *| |
42 | |* (e.g., host, services, ...) *| |
43 | |* *| |
44 | |* ADD_PARAMS - additional parameters, can vary in number *| |
45 | |* *| |
46 | |* ADD_VARIABLES - names of additional parameters *| |
47 | |* *| |
48 | |* Optionally the following vars can be defined: *| |
49 | |* *| |
50 | |* EXTRA_PARAMS - optional parameters, can vary in number *| |
51 | |* *| |
52 | |* EXTRA_VARIABLES - names of optional parameter *| |
53 | |* *| |
54 | |* FUNCTION2_NAME - alternative name of the non-reentrant function *| |
55 | |* *| |
56 | |* NEED_H_ERRNO - an extra parameter will be passed to point to *| |
57 | |* the global `h_errno' variable. *| |
58 | |* *| |
59 | |* NEED__RES - the global _res variable might be used so we *| |
60 | |* will have to initialize it if necessary *| |
61 | |* *| |
62 | |* PREPROCESS - code run before anything else *| |
63 | |* *| |
64 | |* POSTPROCESS - code run after the lookup *| |
65 | |* *| |
66 | \*******************************************************************/ |
67 | |
68 | /* To make the real sources a bit prettier. */ |
69 | #define REENTRANT_NAME APPEND_R (FUNCTION_NAME) |
70 | #ifdef FUNCTION2_NAME |
71 | # define REENTRANT2_NAME APPEND_R (FUNCTION2_NAME) |
72 | #else |
73 | # define REENTRANT2_NAME NULL |
74 | #endif |
75 | #define APPEND_R(name) APPEND_R1 (name) |
76 | #define APPEND_R1(name) name##_r |
77 | #define INTERNAL(name) INTERNAL1 (name) |
78 | #define INTERNAL1(name) __##name |
79 | #define NEW(name) NEW1 (name) |
80 | #define NEW1(name) __new_##name |
81 | |
82 | #ifdef USE_NSCD |
83 | # define NSCD_NAME ADD_NSCD (REENTRANT_NAME) |
84 | # define ADD_NSCD(name) ADD_NSCD1 (name) |
85 | # define ADD_NSCD1(name) __nscd_##name |
86 | # define NOT_USENSCD_NAME ADD_NOT_NSCDUSE (DATABASE_NAME) |
87 | # define ADD_NOT_NSCDUSE(name) ADD_NOT_NSCDUSE1 (name) |
88 | # define ADD_NOT_NSCDUSE1(name) __nss_not_use_nscd_##name |
89 | # define CONCAT2(arg1, arg2) CONCAT2_2 (arg1, arg2) |
90 | # define CONCAT2_2(arg1, arg2) arg1##arg2 |
91 | #endif |
92 | |
93 | #define FUNCTION_NAME_STRING STRINGIZE (FUNCTION_NAME) |
94 | #define REENTRANT_NAME_STRING STRINGIZE (REENTRANT_NAME) |
95 | #ifdef FUNCTION2_NAME |
96 | # define REENTRANT2_NAME_STRING STRINGIZE (REENTRANT2_NAME) |
97 | #else |
98 | # define REENTRANT2_NAME_STRING NULL |
99 | #endif |
100 | #define DATABASE_NAME_STRING STRINGIZE (DATABASE_NAME) |
101 | #define STRINGIZE(name) STRINGIZE1 (name) |
102 | #define STRINGIZE1(name) #name |
103 | |
104 | #ifndef DB_LOOKUP_FCT |
105 | # define DB_LOOKUP_FCT CONCAT3_1 (__nss_, DATABASE_NAME, _lookup2) |
106 | # define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post) |
107 | # define CONCAT3_2(Pre, Name, Post) Pre##Name##Post |
108 | #endif |
109 | |
110 | /* Sometimes we need to store error codes in the `h_errno' variable. */ |
111 | #ifdef NEED_H_ERRNO |
112 | # define H_ERRNO_PARM , int *h_errnop |
113 | # define H_ERRNO_VAR , h_errnop |
114 | # define H_ERRNO_VAR_P h_errnop |
115 | #else |
116 | # define H_ERRNO_PARM |
117 | # define H_ERRNO_VAR |
118 | # define H_ERRNO_VAR_P NULL |
119 | #endif |
120 | |
121 | #ifndef EXTRA_PARAMS |
122 | # define |
123 | #endif |
124 | #ifndef EXTRA_VARIABLES |
125 | # define |
126 | #endif |
127 | |
128 | #ifdef HAVE_AF |
129 | # define AF_VAL af |
130 | #else |
131 | # define AF_VAL AF_INET |
132 | #endif |
133 | |
134 | /* Type of the lookup function we need here. */ |
135 | typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *, |
136 | size_t, int * H_ERRNO_PARM |
137 | EXTRA_PARAMS); |
138 | |
139 | /* The lookup function for the first entry of this service. */ |
140 | extern int DB_LOOKUP_FCT (service_user **nip, const char *name, |
141 | const char *name2, void **fctp) |
142 | internal_function; |
143 | libc_hidden_proto (DB_LOOKUP_FCT) |
144 | |
145 | |
146 | int |
147 | INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer, |
148 | size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM |
149 | EXTRA_PARAMS) |
150 | { |
151 | static bool startp_initialized; |
152 | static service_user *startp; |
153 | static lookup_function start_fct; |
154 | service_user *nip; |
155 | union |
156 | { |
157 | lookup_function l; |
158 | void *ptr; |
159 | } fct; |
160 | |
161 | int no_more; |
162 | enum nss_status status = NSS_STATUS_UNAVAIL; |
163 | #ifdef USE_NSCD |
164 | int nscd_status; |
165 | #endif |
166 | #ifdef NEED_H_ERRNO |
167 | bool any_service = false; |
168 | #endif |
169 | |
170 | #ifdef PREPROCESS |
171 | PREPROCESS; |
172 | #endif |
173 | |
174 | #ifdef HANDLE_DIGITS_DOTS |
175 | switch (__nss_hostname_digits_dots (name, resbuf, &buffer, NULL, |
176 | buflen, result, &status, AF_VAL, |
177 | H_ERRNO_VAR_P)) |
178 | { |
179 | case -1: |
180 | return errno; |
181 | case 1: |
182 | #ifdef NEED_H_ERRNO |
183 | any_service = true; |
184 | #endif |
185 | goto done; |
186 | } |
187 | #endif |
188 | |
189 | #ifdef USE_NSCD |
190 | if (NOT_USENSCD_NAME > 0 && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY) |
191 | NOT_USENSCD_NAME = 0; |
192 | |
193 | if (!NOT_USENSCD_NAME |
194 | && !__nss_database_custom[CONCAT2 (NSS_DBSIDX_, DATABASE_NAME)]) |
195 | { |
196 | nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen, result |
197 | H_ERRNO_VAR); |
198 | if (nscd_status >= 0) |
199 | return nscd_status; |
200 | } |
201 | #endif |
202 | |
203 | if (! startp_initialized) |
204 | { |
205 | no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING, |
206 | REENTRANT2_NAME_STRING, &fct.ptr); |
207 | if (no_more) |
208 | { |
209 | void *tmp_ptr = (service_user *) -1l; |
210 | #ifdef PTR_MANGLE |
211 | PTR_MANGLE (tmp_ptr); |
212 | #endif |
213 | startp = tmp_ptr; |
214 | } |
215 | else |
216 | { |
217 | #ifdef NEED__RES |
218 | /* The resolver code will really be used so we have to |
219 | initialize it. */ |
220 | if (__res_maybe_init (&_res, 0) == -1) |
221 | { |
222 | *h_errnop = NETDB_INTERNAL; |
223 | *result = NULL; |
224 | return errno; |
225 | } |
226 | #endif /* need _res */ |
227 | #ifdef NEED__RES_HCONF |
228 | if (!_res_hconf.initialized) |
229 | _res_hconf_init (); |
230 | #endif /* need _res_hconf */ |
231 | |
232 | void *tmp_ptr = fct.l; |
233 | #ifdef PTR_MANGLE |
234 | PTR_MANGLE (tmp_ptr); |
235 | #endif |
236 | start_fct = tmp_ptr; |
237 | tmp_ptr = nip; |
238 | #ifdef PTR_MANGLE |
239 | PTR_MANGLE (tmp_ptr); |
240 | #endif |
241 | startp = tmp_ptr; |
242 | } |
243 | |
244 | /* Make sure start_fct and startp are written before |
245 | startp_initialized. */ |
246 | atomic_write_barrier (); |
247 | startp_initialized = true; |
248 | } |
249 | else |
250 | { |
251 | fct.l = start_fct; |
252 | nip = startp; |
253 | #ifdef PTR_DEMANGLE |
254 | PTR_DEMANGLE (fct.l); |
255 | PTR_DEMANGLE (nip); |
256 | #endif |
257 | no_more = nip == (service_user *) -1l; |
258 | } |
259 | |
260 | while (no_more == 0) |
261 | { |
262 | #ifdef NEED_H_ERRNO |
263 | any_service = true; |
264 | #endif |
265 | |
266 | status = DL_CALL_FCT (fct.l, (ADD_VARIABLES, resbuf, buffer, buflen, |
267 | &errno H_ERRNO_VAR EXTRA_VARIABLES)); |
268 | |
269 | /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the |
270 | provided buffer is too small. In this case we should give |
271 | the user the possibility to enlarge the buffer and we should |
272 | not simply go on with the next service (even if the TRYAGAIN |
273 | action tells us so). */ |
274 | if (status == NSS_STATUS_TRYAGAIN |
275 | #ifdef NEED_H_ERRNO |
276 | && *h_errnop == NETDB_INTERNAL |
277 | #endif |
278 | && errno == ERANGE) |
279 | break; |
280 | |
281 | no_more = __nss_next2 (&nip, REENTRANT_NAME_STRING, |
282 | REENTRANT2_NAME_STRING, &fct.ptr, status, 0); |
283 | } |
284 | |
285 | #ifdef HANDLE_DIGITS_DOTS |
286 | done: |
287 | #endif |
288 | *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL; |
289 | #ifdef NEED_H_ERRNO |
290 | if (status == NSS_STATUS_UNAVAIL && !any_service && errno != ENOENT) |
291 | /* This happens when we weren't able to use a service for reasons other |
292 | than the module not being found. In such a case, we'd want to tell the |
293 | caller that errno has the real reason for failure. */ |
294 | *h_errnop = NETDB_INTERNAL; |
295 | else if (status != NSS_STATUS_SUCCESS && !any_service) |
296 | /* We were not able to use any service. */ |
297 | *h_errnop = NO_RECOVERY; |
298 | #endif |
299 | #ifdef POSTPROCESS |
300 | POSTPROCESS; |
301 | #endif |
302 | |
303 | int res; |
304 | if (status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND) |
305 | res = 0; |
306 | /* Don't pass back ERANGE if this is not for a too-small buffer. */ |
307 | else if (errno == ERANGE && status != NSS_STATUS_TRYAGAIN) |
308 | res = EINVAL; |
309 | #ifdef NEED_H_ERRNO |
310 | /* These functions only set errno if h_errno is NETDB_INTERNAL. */ |
311 | else if (status == NSS_STATUS_TRYAGAIN && *h_errnop != NETDB_INTERNAL) |
312 | res = EAGAIN; |
313 | #endif |
314 | else |
315 | return errno; |
316 | |
317 | __set_errno (res); |
318 | return res; |
319 | } |
320 | |
321 | |
322 | #ifdef NO_COMPAT_NEEDED |
323 | strong_alias (INTERNAL (REENTRANT_NAME), REENTRANT_NAME); |
324 | #elif !defined FUNCTION2_NAME |
325 | # include <shlib-compat.h> |
326 | # if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2) |
327 | # define OLD(name) OLD1 (name) |
328 | # define OLD1(name) __old_##name |
329 | |
330 | int |
331 | attribute_compat_text_section |
332 | OLD (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer, |
333 | size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM) |
334 | { |
335 | int ret = INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, resbuf, buffer, |
336 | buflen, result H_ERRNO_VAR); |
337 | |
338 | if (ret != 0 || result == NULL) |
339 | ret = -1; |
340 | |
341 | return ret; |
342 | } |
343 | |
344 | # define do_symbol_version(real, name, version) \ |
345 | compat_symbol (libc, real, name, version) |
346 | do_symbol_version (OLD (REENTRANT_NAME), REENTRANT_NAME, GLIBC_2_0); |
347 | # endif |
348 | |
349 | /* As INTERNAL (REENTRANT_NAME) may be hidden, we need an alias |
350 | in between so that the REENTRANT_NAME@@GLIBC_2.1.2 is not |
351 | hidden too. */ |
352 | strong_alias (INTERNAL (REENTRANT_NAME), NEW (REENTRANT_NAME)); |
353 | |
354 | # define do_default_symbol_version(real, name, version) \ |
355 | versioned_symbol (libc, real, name, version) |
356 | do_default_symbol_version (NEW (REENTRANT_NAME), |
357 | REENTRANT_NAME, GLIBC_2_1_2); |
358 | #endif |
359 | |
360 | nss_interface_function (REENTRANT_NAME) |
361 | |