1 /* Copyright (C) 1996-2020 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
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 <https://www.gnu.org/licenses/>. */
23 #include <libc-lock.h>
26 #include <stdio_ext.h>
32 #include <netinet/ether.h>
36 #if !defined DO_STATIC_NSS || defined SHARED
37 # include <gnu/lib-names.h>
41 #include "../nscd/nscd_proto.h"
45 /* Prototypes for the local functions. */
46 static name_database *nss_parse_file (const char *fname);
47 static name_database_entry *nss_getline (char *line);
48 static service_user *nss_parse_service_list (const char *line);
49 #if !defined DO_STATIC_NSS || defined SHARED
50 static service_library *nss_new_service (name_database *database,
55 /* Declare external database variables. */
56 #define DEFINE_DATABASE(name) \
57 service_user *__nss_##name##_database attribute_hidden; \
58 weak_extern (__nss_##name##_database)
59 #include "databases.def"
60 #undef DEFINE_DATABASE
62 /* Structure to map database name to variable. */
69 #define DEFINE_DATABASE(name) \
70 { #name, &__nss_##name##_database },
71 #include "databases.def"
72 #undef DEFINE_DATABASE
74 #define ndatabases (sizeof (databases) / sizeof (databases[0]))
77 /* Flags whether custom rules for database is set. */
78 bool __nss_database_custom[NSS_DBSIDX_max];
82 __libc_lock_define_initialized (static, lock)
84 #if !defined DO_STATIC_NSS || defined SHARED
85 /* String with revision number of the shared object files. */
86 static const char *const __nss_shlib_revision = LIBNSS_FILES_SO + 15;
89 /* The root of the whole data base. */
90 static name_database *service_table;
92 /* List of default service lists that were generated by glibc because
93 /etc/nsswitch.conf did not provide a value.
94 The list is only maintained so we can free such service lists in
96 static name_database_entry *defconfig_entries;
99 #if defined USE_NSCD && (!defined DO_STATIC_NSS || defined SHARED)
100 /* Nonzero if this is the nscd process. */
102 /* The callback passed to the init functions when nscd is used. */
103 static void (*nscd_init_cb) (size_t, struct traced_file *);
107 /* -1 == database not found
108 0 == database entry pointer stored */
110 __nss_database_lookup2 (const char *database, const char *alternate_name,
111 const char *defconfig, service_user **ni)
113 /* Prevent multiple threads to change the service table. */
114 __libc_lock_lock (lock);
116 /* Reconsider database variable in case some other thread called
117 `__nss_configure_lookup' while we waited for the lock. */
120 __libc_lock_unlock (lock);
124 /* Are we initialized yet? */
125 if (service_table == NULL)
126 /* Read config file. */
127 service_table = nss_parse_file (_PATH_NSSWITCH_CONF);
129 /* Test whether configuration data is available. */
130 if (service_table != NULL)
132 /* Return first `service_user' entry for DATABASE. */
133 name_database_entry *entry;
135 /* XXX Could use some faster mechanism here. But each database is
136 only requested once and so this might not be critical. */
137 for (entry = service_table->entry; entry != NULL; entry = entry->next)
138 if (strcmp (database, entry->name) == 0)
139 *ni = entry->service;
141 if (*ni == NULL && alternate_name != NULL)
142 /* We haven't found an entry so far. Try to find it with the
144 for (entry = service_table->entry; entry != NULL; entry = entry->next)
145 if (strcmp (alternate_name, entry->name) == 0)
146 *ni = entry->service;
149 /* No configuration data is available, either because nsswitch.conf
150 doesn't exist or because it doesn't have a line for this database.
152 DEFCONFIG specifies the default service list for this database,
153 or null to use the most common default. */
156 *ni = nss_parse_service_list (defconfig ?: "files");
159 /* Record the memory we've just allocated in defconfig_entries list,
160 so we can free it later. */
161 name_database_entry *entry;
163 /* Allocate ENTRY plus size of name (1 here). */
164 entry = (name_database_entry *) malloc (sizeof (*entry) + 1);
168 entry->next = defconfig_entries;
169 entry->service = *ni;
170 entry->name[0] = '\0';
171 defconfig_entries = entry;
176 __libc_lock_unlock (lock);
178 return *ni != NULL ? 0 : -1;
180 libc_hidden_def (__nss_database_lookup2)
187 __nss_lookup (service_user **ni, const char *fct_name, const char *fct2_name,
190 *fctp = __nss_lookup_function (*ni, fct_name);
191 if (*fctp == NULL && fct2_name != NULL)
192 *fctp = __nss_lookup_function (*ni, fct2_name);
195 && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
196 && (*ni)->next != NULL)
200 *fctp = __nss_lookup_function (*ni, fct_name);
201 if (*fctp == NULL && fct2_name != NULL)
202 *fctp = __nss_lookup_function (*ni, fct2_name);
205 return *fctp != NULL ? 0 : (*ni)->next == NULL ? 1 : -1;
207 libc_hidden_def (__nss_lookup)
211 0 == adjusted for next function
214 __nss_next2 (service_user **ni, const char *fct_name, const char *fct2_name,
215 void **fctp, int status, int all_values)
219 if (nss_next_action (*ni, NSS_STATUS_TRYAGAIN) == NSS_ACTION_RETURN
220 && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_RETURN
221 && nss_next_action (*ni, NSS_STATUS_NOTFOUND) == NSS_ACTION_RETURN
222 && nss_next_action (*ni, NSS_STATUS_SUCCESS) == NSS_ACTION_RETURN)
227 /* This is really only for debugging. */
228 if (__builtin_expect (NSS_STATUS_TRYAGAIN > status
229 || status > NSS_STATUS_RETURN, 0))
230 __libc_fatal ("Illegal status in __nss_next.\n");
232 if (nss_next_action (*ni, status) == NSS_ACTION_RETURN)
236 if ((*ni)->next == NULL)
243 *fctp = __nss_lookup_function (*ni, fct_name);
244 if (*fctp == NULL && fct2_name != NULL)
245 *fctp = __nss_lookup_function (*ni, fct2_name);
248 && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
249 && (*ni)->next != NULL);
251 return *fctp != NULL ? 0 : -1;
253 libc_hidden_def (__nss_next2)
256 __nss_configure_lookup (const char *dbname, const char *service_line)
258 service_user *new_db;
261 for (cnt = 0; cnt < ndatabases; ++cnt)
263 int cmp = strcmp (dbname, databases[cnt].name);
268 __set_errno (EINVAL);
273 if (cnt == ndatabases)
275 __set_errno (EINVAL);
279 /* Test whether it is really used. */
280 if (databases[cnt].dbp == NULL)
281 /* Nothing to do, but we could do. */
284 /* Try to generate new data. */
285 new_db = nss_parse_service_list (service_line);
288 /* Illegal service specification. */
289 __set_errno (EINVAL);
293 /* Prevent multiple threads to change the service table. */
294 __libc_lock_lock (lock);
296 /* Install new rules. */
297 *databases[cnt].dbp = new_db;
299 __nss_database_custom[cnt] = true;
302 __libc_lock_unlock (lock);
308 /* Comparison function for searching NI->known tree. */
310 known_compare (const void *p1, const void *p2)
312 return p1 == p2 ? 0 : strcmp (*(const char *const *) p1,
313 *(const char *const *) p2);
317 #if !defined DO_STATIC_NSS || defined SHARED
320 nss_load_library (service_user *ni)
322 if (ni->library == NULL)
324 /* This service has not yet been used. Fetch the service
325 library for it, creating a new one if need be. If there
326 is no service table from the file, this static variable
327 holds the head of the service_library list made from the
328 default configuration. */
329 static name_database default_table;
330 ni->library = nss_new_service (service_table ?: &default_table,
332 if (ni->library == NULL)
336 if (ni->library->lib_handle == NULL)
338 /* Load the shared library. */
339 size_t shlen = (7 + strlen (ni->name) + 3
340 + strlen (__nss_shlib_revision) + 1);
341 int saved_errno = errno;
342 char shlib_name[shlen];
344 /* Construct shared object name. */
345 __stpcpy (__stpcpy (__stpcpy (__stpcpy (shlib_name,
349 __nss_shlib_revision);
351 ni->library->lib_handle = __libc_dlopen (shlib_name);
352 if (ni->library->lib_handle == NULL)
354 /* Failed to load the library. */
355 ni->library->lib_handle = (void *) -1l;
356 __set_errno (saved_errno);
361 /* Call the init function when nscd is used. */
362 size_t initlen = (5 + strlen (ni->name)
363 + strlen ("_init") + 1);
364 char init_name[initlen];
366 /* Construct the init function name. */
367 __stpcpy (__stpcpy (__stpcpy (init_name,
372 /* Find the optional init function. */
373 void (*ifct) (void (*) (size_t, struct traced_file *))
374 = __libc_dlsym (ni->library->lib_handle, init_name);
377 void (*cb) (size_t, struct traced_file *) = nscd_init_cb;
393 __nss_lookup_function (service_user *ni, const char *fct_name)
395 void **found, *result;
397 /* We now modify global data. Protect it. */
398 __libc_lock_lock (lock);
400 /* Search the tree of functions previously requested. Data in the
401 tree are `known_function' structures, whose first member is a
402 `const char *', the lookup key. The search returns a pointer to
403 the tree node structure; the first member of the is a pointer to
404 our structure (i.e. what will be a `known_function'); since the
405 first member of that is the lookup key string, &FCT_NAME is close
406 enough to a pointer to our structure to use as a lookup key that
407 will be passed to `known_compare' (above). */
409 found = __tsearch (&fct_name, &ni->known, &known_compare);
411 /* This means out-of-memory. */
413 else if (*found != &fct_name)
415 /* The search found an existing structure in the tree. */
416 result = ((known_function *) *found)->fct_ptr;
418 PTR_DEMANGLE (result);
423 /* This name was not known before. Now we have a node in the tree
424 (in the proper sorted position for FCT_NAME) that points to
425 &FCT_NAME instead of any real `known_function' structure.
426 Allocate a new structure and fill it in. */
428 known_function *known = malloc (sizeof *known);
431 #if !defined DO_STATIC_NSS || defined SHARED
434 /* Oops. We can't instantiate this node properly.
435 Remove it from the tree. */
436 __tdelete (&fct_name, &ni->known, &known_compare);
442 /* Point the tree node at this new structure. */
444 known->fct_name = fct_name;
446 #if !defined DO_STATIC_NSS || defined SHARED
447 /* Load the appropriate library. */
448 if (nss_load_library (ni) != 0)
449 /* This only happens when out of memory. */
450 goto remove_from_tree;
452 if (ni->library->lib_handle == (void *) -1l)
453 /* Library not found => function not found. */
457 /* Get the desired function. */
458 size_t namlen = (5 + strlen (ni->name) + 1
459 + strlen (fct_name) + 1);
462 /* Construct the function name. */
463 __stpcpy (__stpcpy (__stpcpy (__stpcpy (name, "_nss_"),
468 /* Look up the symbol. */
469 result = __libc_dlsym (ni->library->lib_handle, name);
472 /* We can't get function address dynamically in static linking. */
474 # define DEFINE_ENT(h,nm) \
475 { #h"_get"#nm"ent_r", _nss_##h##_get##nm##ent_r }, \
476 { #h"_end"#nm"ent", _nss_##h##_end##nm##ent }, \
477 { #h"_set"#nm"ent", _nss_##h##_set##nm##ent },
478 # define DEFINE_GET(h,nm) \
479 { #h"_get"#nm"_r", _nss_##h##_get##nm##_r },
480 # define DEFINE_GETBY(h,nm,ky) \
481 { #h"_get"#nm"by"#ky"_r", _nss_##h##_get##nm##by##ky##_r },
482 static struct fct_tbl { const char *fname; void *fp; } *tp, tbl[] =
484 # include "function.def"
487 size_t namlen = (5 + strlen (ni->name) + 1
488 + strlen (fct_name) + 1);
491 /* Construct the function name. */
492 __stpcpy (__stpcpy (__stpcpy (name, ni->name),
497 for (tp = &tbl[0]; tp->fname; tp++)
498 if (strcmp (tp->fname, name) == 0)
506 /* Remember function pointer for later calls. Even if null, we
507 record it so a second try needn't search the library again. */
508 known->fct_ptr = result;
510 PTR_MANGLE (known->fct_ptr);
515 /* Remove the lock. */
516 __libc_lock_unlock (lock);
520 libc_hidden_def (__nss_lookup_function)
523 static name_database *
524 nss_parse_file (const char *fname)
527 name_database *result;
528 name_database_entry *last;
532 /* Open the configuration file. */
533 fp = fopen (fname, "rce");
537 /* No threads use this stream. */
538 __fsetlocking (fp, FSETLOCKING_BYCALLER);
540 result = (name_database *) malloc (sizeof (name_database));
547 result->entry = NULL;
548 result->library = NULL;
554 name_database_entry *this;
557 n = __getline (&line, &len, fp);
560 if (line[n - 1] == '\n')
563 /* Because the file format does not know any form of quoting we
564 can search forward for the next '#' character and if found
565 make it terminating the line. */
566 *__strchrnul (line, '#') = '\0';
568 /* If the line is blank it is ignored. */
572 /* Each line completely specifies the actions for a database. */
573 this = nss_getline (line);
579 result->entry = this;
584 while (!__feof_unlocked (fp));
586 /* Free the buffer. */
588 /* Close configuration file. */
595 /* Read the source names:
596 `( <source> ( "[" "!"? (<status> "=" <action> )+ "]" )? )*'
598 static service_user *
599 nss_parse_service_list (const char *line)
601 service_user *result = NULL, **nextp = &result;
605 service_user *new_service;
608 while (isspace (line[0]))
611 /* No source specified. */
614 /* Read <source> identifier. */
616 while (line[0] != '\0' && !isspace (line[0]) && line[0] != '[')
622 new_service = (service_user *) malloc (sizeof (service_user)
623 + (line - name + 1));
624 if (new_service == NULL)
627 *((char *) __mempcpy (new_service->name, name, line - name)) = '\0';
629 /* Set default actions. */
630 new_service->actions[2 + NSS_STATUS_TRYAGAIN] = NSS_ACTION_CONTINUE;
631 new_service->actions[2 + NSS_STATUS_UNAVAIL] = NSS_ACTION_CONTINUE;
632 new_service->actions[2 + NSS_STATUS_NOTFOUND] = NSS_ACTION_CONTINUE;
633 new_service->actions[2 + NSS_STATUS_SUCCESS] = NSS_ACTION_RETURN;
634 new_service->actions[2 + NSS_STATUS_RETURN] = NSS_ACTION_RETURN;
635 new_service->library = NULL;
636 new_service->known = NULL;
637 new_service->next = NULL;
639 while (isspace (line[0]))
644 /* Read criterions. */
647 while (line[0] != '\0' && isspace (line[0]));
652 enum nss_status status;
653 lookup_actions action;
655 /* Grok ! before name to mean all statii but that one. */
656 not = line[0] == '!';
660 /* Read status name. */
662 while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
666 /* Compare with known statii. */
667 if (line - name == 7)
669 if (__strncasecmp (name, "SUCCESS", 7) == 0)
670 status = NSS_STATUS_SUCCESS;
671 else if (__strncasecmp (name, "UNAVAIL", 7) == 0)
672 status = NSS_STATUS_UNAVAIL;
676 else if (line - name == 8)
678 if (__strncasecmp (name, "NOTFOUND", 8) == 0)
679 status = NSS_STATUS_NOTFOUND;
680 else if (__strncasecmp (name, "TRYAGAIN", 8) == 0)
681 status = NSS_STATUS_TRYAGAIN;
688 while (isspace (line[0]))
694 while (isspace (line[0]));
697 while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
701 if (line - name == 6 && __strncasecmp (name, "RETURN", 6) == 0)
702 action = NSS_ACTION_RETURN;
703 else if (line - name == 8
704 && __strncasecmp (name, "CONTINUE", 8) == 0)
705 action = NSS_ACTION_CONTINUE;
706 else if (line - name == 5
707 && __strncasecmp (name, "MERGE", 5) == 0)
708 action = NSS_ACTION_MERGE;
714 /* Save the current action setting for this status,
715 set them all to the given action, and reset this one. */
716 const lookup_actions save = new_service->actions[2 + status];
717 new_service->actions[2 + NSS_STATUS_TRYAGAIN] = action;
718 new_service->actions[2 + NSS_STATUS_UNAVAIL] = action;
719 new_service->actions[2 + NSS_STATUS_NOTFOUND] = action;
720 new_service->actions[2 + NSS_STATUS_SUCCESS] = action;
721 new_service->actions[2 + status] = save;
724 new_service->actions[2 + status] = action;
726 /* Skip white spaces. */
727 while (isspace (line[0]))
730 while (line[0] != ']');
736 *nextp = new_service;
737 nextp = &new_service->next;
746 static name_database_entry *
747 nss_getline (char *line)
750 name_database_entry *result;
753 /* Ignore leading white spaces. ATTENTION: this is different from
754 what is implemented in Solaris. The Solaris man page says a line
755 beginning with a white space character is ignored. We regard
756 this as just another misfeature in Solaris. */
757 while (isspace (line[0]))
760 /* Recognize `<database> ":"'. */
762 while (line[0] != '\0' && !isspace (line[0]) && line[0] != ':')
764 if (line[0] == '\0' || name == line)
769 len = strlen (name) + 1;
771 result = (name_database_entry *) malloc (sizeof (name_database_entry) + len);
775 /* Save the database name. */
776 memcpy (result->name, name, len);
778 /* Parse the list of services. */
779 result->service = nss_parse_service_list (line);
786 #if !defined DO_STATIC_NSS || defined SHARED
787 static service_library *
788 nss_new_service (name_database *database, const char *name)
790 service_library **currentp = &database->library;
792 while (*currentp != NULL)
794 if (strcmp ((*currentp)->name, name) == 0)
796 currentp = &(*currentp)->next;
799 /* We have to add the new service. */
800 *currentp = (service_library *) malloc (sizeof (service_library));
801 if (*currentp == NULL)
804 (*currentp)->name = name;
805 (*currentp)->lib_handle = NULL;
806 (*currentp)->next = NULL;
813 #if defined SHARED && defined USE_NSCD
814 /* Load all libraries for the service. */
816 nss_load_all_libraries (const char *service, const char *def)
818 service_user *ni = NULL;
820 if (__nss_database_lookup2 (service, NULL, def, &ni) == 0)
823 nss_load_library (ni);
829 /* Called by nscd and nscd alone. */
831 __nss_disable_nscd (void (*cb) (size_t, struct traced_file *))
839 /* Find all the relevant modules so that the init functions are called. */
840 nss_load_all_libraries ("passwd", "files");
841 nss_load_all_libraries ("group", "files");
842 nss_load_all_libraries ("hosts", "dns [!UNAVAIL=return] files");
843 nss_load_all_libraries ("services", NULL);
845 /* Disable all uses of NSCD. */
846 __nss_not_use_nscd_passwd = -1;
847 __nss_not_use_nscd_group = -1;
848 __nss_not_use_nscd_hosts = -1;
849 __nss_not_use_nscd_services = -1;
850 __nss_not_use_nscd_netgroup = -1;
855 free_database_entries (name_database_entry *entry)
857 while (entry != NULL)
859 name_database_entry *olde = entry;
860 service_user *service = entry->service;
862 while (service != NULL)
864 service_user *olds = service;
866 if (service->known != NULL)
867 __tdestroy (service->known, free);
869 service = service->next;
878 /* Free all resources if necessary. */
879 libc_freeres_fn (free_defconfig)
881 name_database_entry *entry = defconfig_entries;
884 /* defconfig was not used. */
887 /* Don't disturb ongoing other threads (if there are any). */
888 defconfig_entries = NULL;
890 free_database_entries (entry);
893 libc_freeres_fn (free_mem)
895 name_database *top = service_table;
896 service_library *library;
899 /* Maybe we have not read the nsswitch.conf file. */
902 /* Don't disturb ongoing other threads (if there are any). */
903 service_table = NULL;
905 free_database_entries (top->entry);
907 library = top->library;
908 while (library != NULL)
910 service_library *oldl = library;
912 if (library->lib_handle && library->lib_handle != (void *) -1l)
913 __libc_dlclose (library->lib_handle);
915 library = library->next;