1/* Copyright (C) 1996-2017 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 EXTRA_PARAMS
123#endif
124#ifndef EXTRA_VARIABLES
125# define EXTRA_VARIABLES
126#endif
127
128#ifdef HAVE_AF
129# define AF_VAL af
130#else
131# define AF_VAL AF_INET
132#endif
133
134
135/* Set defaults for merge functions that haven't been defined. */
136#ifndef DEEPCOPY_FN
137static inline int
138__copy_einval (LOOKUP_TYPE a,
139 const size_t b,
140 LOOKUP_TYPE *c,
141 char *d,
142 char **e)
143{
144 return EINVAL;
145}
146# define DEEPCOPY_FN __copy_einval
147#endif
148
149#ifndef MERGE_FN
150static inline int
151__merge_einval (LOOKUP_TYPE *a,
152 char *b,
153 char *c,
154 size_t d,
155 LOOKUP_TYPE *e,
156 char *f)
157{
158 return EINVAL;
159}
160# define MERGE_FN __merge_einval
161#endif
162
163#define CHECK_MERGE(err, status) \
164 ({ \
165 do \
166 { \
167 if (err) \
168 { \
169 __set_errno (err); \
170 if (err == ERANGE) \
171 status = NSS_STATUS_TRYAGAIN; \
172 else \
173 status = NSS_STATUS_UNAVAIL; \
174 break; \
175 } \
176 } \
177 while (0); \
178 })
179
180/* Type of the lookup function we need here. */
181typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,
182 size_t, int * H_ERRNO_PARM
183 EXTRA_PARAMS);
184
185/* The lookup function for the first entry of this service. */
186extern int DB_LOOKUP_FCT (service_user **nip, const char *name,
187 const char *name2, void **fctp)
188 internal_function;
189libc_hidden_proto (DB_LOOKUP_FCT)
190
191
192int
193INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
194 size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM
195 EXTRA_PARAMS)
196{
197 static bool startp_initialized;
198 static service_user *startp;
199 static lookup_function start_fct;
200 service_user *nip;
201 int do_merge = 0;
202 LOOKUP_TYPE mergegrp;
203 char *mergebuf = NULL;
204 char *endptr = NULL;
205 union
206 {
207 lookup_function l;
208 void *ptr;
209 } fct;
210 int no_more, err;
211 enum nss_status status = NSS_STATUS_UNAVAIL;
212#ifdef USE_NSCD
213 int nscd_status;
214#endif
215#ifdef NEED_H_ERRNO
216 bool any_service = false;
217#endif
218
219#ifdef PREPROCESS
220 PREPROCESS;
221#endif
222
223#ifdef HANDLE_DIGITS_DOTS
224 switch (__nss_hostname_digits_dots (name, resbuf, &buffer, NULL,
225 buflen, result, &status, AF_VAL,
226 H_ERRNO_VAR_P))
227 {
228 case -1:
229 return errno;
230 case 1:
231#ifdef NEED_H_ERRNO
232 any_service = true;
233#endif
234 goto done;
235 }
236#endif
237
238#ifdef USE_NSCD
239 if (NOT_USENSCD_NAME > 0 && ++NOT_USENSCD_NAME > NSS_NSCD_RETRY)
240 NOT_USENSCD_NAME = 0;
241
242 if (!NOT_USENSCD_NAME
243 && !__nss_database_custom[CONCAT2 (NSS_DBSIDX_, DATABASE_NAME)])
244 {
245 nscd_status = NSCD_NAME (ADD_VARIABLES, resbuf, buffer, buflen, result
246 H_ERRNO_VAR);
247 if (nscd_status >= 0)
248 return nscd_status;
249 }
250#endif
251
252 if (! startp_initialized)
253 {
254 no_more = DB_LOOKUP_FCT (&nip, REENTRANT_NAME_STRING,
255 REENTRANT2_NAME_STRING, &fct.ptr);
256 if (no_more)
257 {
258 void *tmp_ptr = (service_user *) -1l;
259#ifdef PTR_MANGLE
260 PTR_MANGLE (tmp_ptr);
261#endif
262 startp = tmp_ptr;
263 }
264 else
265 {
266#ifdef NEED__RES
267 /* The resolver code will really be used so we have to
268 initialize it. */
269 if (__res_maybe_init (&_res, 0) == -1)
270 {
271 *h_errnop = NETDB_INTERNAL;
272 *result = NULL;
273 return errno;
274 }
275#endif /* need _res */
276#ifdef NEED__RES_HCONF
277 _res_hconf_init ();
278#endif /* need _res_hconf */
279
280 void *tmp_ptr = fct.l;
281#ifdef PTR_MANGLE
282 PTR_MANGLE (tmp_ptr);
283#endif
284 start_fct = tmp_ptr;
285 tmp_ptr = nip;
286#ifdef PTR_MANGLE
287 PTR_MANGLE (tmp_ptr);
288#endif
289 startp = tmp_ptr;
290 }
291
292 /* Make sure start_fct and startp are written before
293 startp_initialized. */
294 atomic_write_barrier ();
295 startp_initialized = true;
296 }
297 else
298 {
299 fct.l = start_fct;
300 nip = startp;
301#ifdef PTR_DEMANGLE
302 PTR_DEMANGLE (fct.l);
303 PTR_DEMANGLE (nip);
304#endif
305 no_more = nip == (service_user *) -1l;
306 }
307
308 while (no_more == 0)
309 {
310#ifdef NEED_H_ERRNO
311 any_service = true;
312#endif
313
314 status = DL_CALL_FCT (fct.l, (ADD_VARIABLES, resbuf, buffer, buflen,
315 &errno H_ERRNO_VAR EXTRA_VARIABLES));
316
317 /* The status is NSS_STATUS_TRYAGAIN and errno is ERANGE the
318 provided buffer is too small. In this case we should give
319 the user the possibility to enlarge the buffer and we should
320 not simply go on with the next service (even if the TRYAGAIN
321 action tells us so). */
322 if (status == NSS_STATUS_TRYAGAIN
323#ifdef NEED_H_ERRNO
324 && *h_errnop == NETDB_INTERNAL
325#endif
326 && errno == ERANGE)
327 break;
328
329 if (do_merge)
330 {
331
332 if (status == NSS_STATUS_SUCCESS)
333 {
334 /* The previous loop saved a buffer for merging.
335 Perform the merge now. */
336 err = MERGE_FN (&mergegrp, mergebuf, endptr, buflen, resbuf,
337 buffer);
338 CHECK_MERGE (err,status);
339 do_merge = 0;
340 }
341 else
342 {
343 /* If the result wasn't SUCCESS, copy the saved buffer back
344 into the result buffer and set the status back to
345 NSS_STATUS_SUCCESS to match the previous pass through the
346 loop.
347 * If the next action is CONTINUE, it will overwrite the value
348 currently in the buffer and return the new value.
349 * If the next action is RETURN, we'll return the previously-
350 acquired values.
351 * If the next action is MERGE, then it will be added to the
352 buffer saved from the previous source. */
353 err = DEEPCOPY_FN (mergegrp, buflen, resbuf, buffer, NULL);
354 CHECK_MERGE (err, status);
355 status = NSS_STATUS_SUCCESS;
356 }
357 }
358
359 /* If we were are configured to merge this value with the next one,
360 save the current value of the group struct. */
361 if (nss_next_action (nip, status) == NSS_ACTION_MERGE
362 && status == NSS_STATUS_SUCCESS)
363 {
364 /* Copy the current values into a buffer to be merged with the next
365 set of retrieved values. */
366 if (mergebuf == NULL)
367 {
368 /* Only allocate once and reuse it for as many merges as we need
369 to perform. */
370 mergebuf = malloc (buflen);
371 if (mergebuf == NULL)
372 {
373 __set_errno (ENOMEM);
374 status = NSS_STATUS_UNAVAIL;
375 break;
376 }
377 }
378
379 err = DEEPCOPY_FN (*resbuf, buflen, &mergegrp, mergebuf, &endptr);
380 CHECK_MERGE (err, status);
381 do_merge = 1;
382 }
383
384 no_more = __nss_next2 (&nip, REENTRANT_NAME_STRING,
385 REENTRANT2_NAME_STRING, &fct.ptr, status, 0);
386 }
387 free (mergebuf);
388 mergebuf = NULL;
389
390#ifdef HANDLE_DIGITS_DOTS
391done:
392#endif
393 *result = status == NSS_STATUS_SUCCESS ? resbuf : NULL;
394#ifdef NEED_H_ERRNO
395 if (status == NSS_STATUS_UNAVAIL && !any_service && errno != ENOENT)
396 /* This happens when we weren't able to use a service for reasons other
397 than the module not being found. In such a case, we'd want to tell the
398 caller that errno has the real reason for failure. */
399 *h_errnop = NETDB_INTERNAL;
400 else if (status != NSS_STATUS_SUCCESS && !any_service)
401 /* We were not able to use any service. */
402 *h_errnop = NO_RECOVERY;
403#endif
404#ifdef POSTPROCESS
405 POSTPROCESS;
406#endif
407
408 int res;
409 if (status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND)
410 res = 0;
411 /* Don't pass back ERANGE if this is not for a too-small buffer. */
412 else if (errno == ERANGE && status != NSS_STATUS_TRYAGAIN)
413 res = EINVAL;
414#ifdef NEED_H_ERRNO
415 /* These functions only set errno if h_errno is NETDB_INTERNAL. */
416 else if (status == NSS_STATUS_TRYAGAIN && *h_errnop != NETDB_INTERNAL)
417 res = EAGAIN;
418#endif
419 else
420 return errno;
421
422 __set_errno (res);
423 return res;
424}
425
426
427#ifdef NO_COMPAT_NEEDED
428strong_alias (INTERNAL (REENTRANT_NAME), REENTRANT_NAME);
429#elif !defined FUNCTION2_NAME
430# include <shlib-compat.h>
431# if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1_2)
432# define OLD(name) OLD1 (name)
433# define OLD1(name) __old_##name
434
435int
436attribute_compat_text_section
437OLD (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf, char *buffer,
438 size_t buflen, LOOKUP_TYPE **result H_ERRNO_PARM)
439{
440 int ret = INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, resbuf, buffer,
441 buflen, result H_ERRNO_VAR);
442
443 if (ret != 0 || result == NULL)
444 ret = -1;
445
446 return ret;
447}
448
449# define do_symbol_version(real, name, version) \
450 compat_symbol (libc, real, name, version)
451do_symbol_version (OLD (REENTRANT_NAME), REENTRANT_NAME, GLIBC_2_0);
452# endif
453
454/* As INTERNAL (REENTRANT_NAME) may be hidden, we need an alias
455 in between so that the REENTRANT_NAME@@GLIBC_2.1.2 is not
456 hidden too. */
457strong_alias (INTERNAL (REENTRANT_NAME), NEW (REENTRANT_NAME));
458
459# define do_default_symbol_version(real, name, version) \
460 versioned_symbol (libc, real, name, version)
461do_default_symbol_version (NEW (REENTRANT_NAME),
462 REENTRANT_NAME, GLIBC_2_1_2);
463#endif
464
465nss_interface_function (REENTRANT_NAME)
466