/* Copyright (C) 1996-2012 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper , 1996. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if !defined DO_STATIC_NSS || defined SHARED # include #endif #include "nsswitch.h" #include "../nscd/nscd_proto.h" #include /* When OPTION_EGLIBC_NSSWITCH is disabled, we use fixed tables of databases and services, generated at library build time. Thus: - We can't reconfigure individual databases, so we don't need a name-to-database map. - We never add databases or service libraries, or look up functions at runtime, so there's no need for a lock to protect our tables. See ../option-groups.def for the details. */ #if __OPTION_EGLIBC_NSSWITCH /* Prototypes for the local functions. */ static name_database *nss_parse_file (const char *fname) internal_function; static name_database_entry *nss_getline (char *line) internal_function; static service_user *nss_parse_service_list (const char *line) internal_function; static service_library *nss_new_service (name_database *database, const char *name) internal_function; /* Declare external database variables. */ #define DEFINE_DATABASE(name) \ extern service_user *__nss_##name##_database attribute_hidden; \ weak_extern (__nss_##name##_database) #include "databases.def" #undef DEFINE_DATABASE /* Structure to map database name to variable. */ static const struct { const char name[10]; service_user **dbp; } databases[] = { #define DEFINE_DATABASE(name) \ { #name, &__nss_##name##_database }, #include "databases.def" #undef DEFINE_DATABASE }; #define ndatabases (sizeof (databases) / sizeof (databases[0])) /* Flags whether custom rules for database is set. */ bool __nss_database_custom[NSS_DBSIDX_max]; __libc_lock_define_initialized (static, lock) #define lock_nsswitch __libc_lock_lock (lock) #define unlock_nsswitch __libc_lock_unlock (lock) #if !defined DO_STATIC_NSS || defined SHARED /* String with revision number of the shared object files. */ static const char *const __nss_shlib_revision = LIBNSS_FILES_SO + 15; #endif /* The root of the whole data base. */ static name_database *service_table; /* List of default service lists that were generated by glibc because /etc/nsswitch.conf did not provide a value. The list is only maintained so we can free such service lists in __libc_freeres. */ static name_database_entry *defconfig_entries; #else /* __OPTION_EGLIBC_NSSWITCH */ /* Bring in the statically initialized service table we generated at build time. */ #include "fixed-nsswitch.h" const static name_database *service_table = &fixed_name_database; /* Nothing ever changes, so there's no need to lock anything. */ #define lock_nsswitch (0) #define unlock_nsswitch (0) #endif /* __OPTION_EGLIBC_NSSWITCH */ /* Nonzero if this is the nscd process. */ static bool is_nscd; /* The callback passed to the init functions when nscd is used. */ static void (*nscd_init_cb) (size_t, struct traced_file *); /* -1 == database not found 0 == database entry pointer stored */ int __nss_database_lookup (const char *database, const char *alternate_name, const char *defconfig, service_user **ni) { /* Prevent multiple threads to change the service table. */ lock_nsswitch; /* Reconsider database variable in case some other thread called `__nss_configure_lookup' while we waited for the lock. */ if (*ni != NULL) { unlock_nsswitch; return 0; } #if __OPTION_EGLIBC_NSSWITCH /* Are we initialized yet? */ if (service_table == NULL) /* Read config file. */ service_table = nss_parse_file (_PATH_NSSWITCH_CONF); #endif /* Test whether configuration data is available. */ if (service_table != NULL) { /* Return first `service_user' entry for DATABASE. */ name_database_entry *entry; /* XXX Could use some faster mechanism here. But each database is only requested once and so this might not be critical. */ for (entry = service_table->entry; entry != NULL; entry = entry->next) if (strcmp (database, entry->name) == 0) *ni = entry->service; if (*ni == NULL && alternate_name != NULL) /* We haven't found an entry so far. Try to find it with the alternative name. */ for (entry = service_table->entry; entry != NULL; entry = entry->next) if (strcmp (alternate_name, entry->name) == 0) *ni = entry->service; } #if __OPTION_EGLIBC_NSSWITCH /* No configuration data is available, either because nsswitch.conf doesn't exist or because it doesn't have a line for this database. DEFCONFIG specifies the default service list for this database, or null to use the most common default. */ if (*ni == NULL) { *ni = nss_parse_service_list (defconfig ?: "nis [NOTFOUND=return] files"); if (*ni != NULL) { /* Record the memory we've just allocated in defconfig_entries list, so we can free it later. */ name_database_entry *entry; /* Allocate ENTRY plus size of name (1 here). */ entry = (name_database_entry *) malloc (sizeof (*entry) + 1); if (entry != NULL) { entry->next = defconfig_entries; entry->service = *ni; entry->name[0] = '\0'; defconfig_entries = entry; } } } #else /* Without the dynamic behavior, we can't process defconfig. The databases the user specified at library build time are all you get. */ if (*ni == NULL) { unlock_nsswitch; return -1; } #endif unlock_nsswitch; return *ni != NULL ? 0 : -1; } libc_hidden_def (__nss_database_lookup) /* -1 == not found 0 == function found 1 == finished */ int __nss_lookup (service_user **ni, const char *fct_name, const char *fct2_name, void **fctp) { *fctp = __nss_lookup_function (*ni, fct_name); if (*fctp == NULL && fct2_name != NULL) *fctp = __nss_lookup_function (*ni, fct2_name); while (*fctp == NULL && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE && (*ni)->next != NULL) { *ni = (*ni)->next; *fctp = __nss_lookup_function (*ni, fct_name); if (*fctp == NULL && fct2_name != NULL) *fctp = __nss_lookup_function (*ni, fct2_name); } return *fctp != NULL ? 0 : (*ni)->next == NULL ? 1 : -1; } libc_hidden_def (__nss_lookup) /* -1 == not found 0 == adjusted for next function 1 == finished */ int __nss_next2 (service_user **ni, const char *fct_name, const char *fct2_name, void **fctp, int status, int all_values) { if (all_values) { if (nss_next_action (*ni, NSS_STATUS_TRYAGAIN) == NSS_ACTION_RETURN && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_RETURN && nss_next_action (*ni, NSS_STATUS_NOTFOUND) == NSS_ACTION_RETURN && nss_next_action (*ni, NSS_STATUS_SUCCESS) == NSS_ACTION_RETURN) return 1; } else { /* This is really only for debugging. */ if (__builtin_expect (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN, 0)) __libc_fatal ("illegal status in __nss_next"); if (nss_next_action (*ni, status) == NSS_ACTION_RETURN) return 1; } if ((*ni)->next == NULL) return -1; do { *ni = (*ni)->next; *fctp = __nss_lookup_function (*ni, fct_name); if (*fctp == NULL && fct2_name != NULL) *fctp = __nss_lookup_function (*ni, fct2_name); } while (*fctp == NULL && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE && (*ni)->next != NULL); return *fctp != NULL ? 0 : -1; } libc_hidden_def (__nss_next2) #if __OPTION_EGLIBC_NSSWITCH int attribute_compat_text_section __nss_next (service_user **ni, const char *fct_name, void **fctp, int status, int all_values) { return __nss_next2 (ni, fct_name, NULL, fctp, status, all_values); } int __nss_configure_lookup (const char *dbname, const char *service_line) { service_user *new_db; size_t cnt; for (cnt = 0; cnt < ndatabases; ++cnt) { int cmp = strcmp (dbname, databases[cnt].name); if (cmp == 0) break; if (cmp < 0) { __set_errno (EINVAL); return -1; } } if (cnt == ndatabases) { __set_errno (EINVAL); return -1; } /* Test whether it is really used. */ if (databases[cnt].dbp == NULL) /* Nothing to do, but we could do. */ return 0; /* Try to generate new data. */ new_db = nss_parse_service_list (service_line); if (new_db == NULL) { /* Illegal service specification. */ __set_errno (EINVAL); return -1; } /* Prevent multiple threads to change the service table. */ lock_nsswitch; /* Install new rules. */ *databases[cnt].dbp = new_db; __nss_database_custom[cnt] = true; unlock_nsswitch; return 0; } /* Comparison function for searching NI->known tree. */ static int known_compare (const void *p1, const void *p2) { return p1 == p2 ? 0 : strcmp (*(const char *const *) p1, *(const char *const *) p2); } #if !defined DO_STATIC_NSS || defined SHARED /* Load library. */ static int nss_load_library (service_user *ni) { if (ni->library == NULL) { /* This service has not yet been used. Fetch the service library for it, creating a new one if need be. If there is no service table from the file, this static variable holds the head of the service_library list made from the default configuration. */ static name_database default_table; ni->library = nss_new_service (service_table ?: &default_table, ni->name); if (ni->library == NULL) return -1; } if (ni->library->lib_handle == NULL) { /* Load the shared library. */ size_t shlen = (7 + strlen (ni->name) + 3 + strlen (__nss_shlib_revision) + 1); int saved_errno = errno; char shlib_name[shlen]; /* Construct shared object name. */ __stpcpy (__stpcpy (__stpcpy (__stpcpy (shlib_name, "libnss_"), ni->name), ".so"), __nss_shlib_revision); ni->library->lib_handle = __libc_dlopen (shlib_name); if (ni->library->lib_handle == NULL) { /* Failed to load the library. */ ni->library->lib_handle = (void *) -1l; __set_errno (saved_errno); } else if (is_nscd) { /* Call the init function when nscd is used. */ size_t initlen = (5 + strlen (ni->name) + strlen ("_init") + 1); char init_name[initlen]; /* Construct the init function name. */ __stpcpy (__stpcpy (__stpcpy (init_name, "_nss_"), ni->name), "_init"); /* Find the optional init function. */ void (*ifct) (void (*) (size_t, struct traced_file *)) = __libc_dlsym (ni->library->lib_handle, init_name); if (ifct != NULL) { void (*cb) (size_t, struct traced_file *) = nscd_init_cb; # ifdef PTR_DEMANGLE PTR_DEMANGLE (cb); # endif ifct (cb); } } } return 0; } #endif void * __nss_lookup_function (service_user *ni, const char *fct_name) { void **found, *result; /* We now modify global data. Protect it. */ lock_nsswitch; /* Search the tree of functions previously requested. Data in the tree are `known_function' structures, whose first member is a `const char *', the lookup key. The search returns a pointer to the tree node structure; the first member of the is a pointer to our structure (i.e. what will be a `known_function'); since the first member of that is the lookup key string, &FCT_NAME is close enough to a pointer to our structure to use as a lookup key that will be passed to `known_compare' (above). */ found = __tsearch (&fct_name, &ni->known.tree, &known_compare); if (found == NULL) /* This means out-of-memory. */ result = NULL; else if (*found != &fct_name) { /* The search found an existing structure in the tree. */ result = ((known_function *) *found)->fct_ptr; PTR_DEMANGLE (result); } else { /* This name was not known before. Now we have a node in the tree (in the proper sorted position for FCT_NAME) that points to &FCT_NAME instead of any real `known_function' structure. Allocate a new structure and fill it in. */ known_function *known = malloc (sizeof *known); if (! known) { remove_from_tree: /* Oops. We can't instantiate this node properly. Remove it from the tree. */ __tdelete (&fct_name, &ni->known.tree, &known_compare); free (known); result = NULL; } else { /* Point the tree node at this new structure. */ *found = known; known->fct_name = fct_name; #if !defined DO_STATIC_NSS || defined SHARED /* Load the appropriate library. */ if (nss_load_library (ni) != 0) /* This only happens when out of memory. */ goto remove_from_tree; if (ni->library->lib_handle == (void *) -1l) /* Library not found => function not found. */ result = NULL; else { /* Get the desired function. */ size_t namlen = (5 + strlen (ni->name) + 1 + strlen (fct_name) + 1); char name[namlen]; /* Construct the function name. */ __stpcpy (__stpcpy (__stpcpy (__stpcpy (name, "_nss_"), ni->name), "_"), fct_name); /* Look up the symbol. */ result = __libc_dlsym (ni->library->lib_handle, name); } #else /* We can't get function address dynamically in static linking. */ { # define DEFINE_ENT(h,nm) \ { #h"_get"#nm"ent_r", _nss_##h##_get##nm##ent_r }, \ { #h"_end"#nm"ent", _nss_##h##_end##nm##ent }, \ { #h"_set"#nm"ent", _nss_##h##_set##nm##ent }, # define DEFINE_GET(h,nm) \ { #h"_get"#nm"_r", _nss_##h##_get##nm##_r }, # define DEFINE_GETBY(h,nm,ky) \ { #h"_get"#nm"by"#ky"_r", _nss_##h##_get##nm##by##ky##_r }, static struct fct_tbl { const char *fname; void *fp; } *tp, tbl[] = { # include "function.def" { NULL, NULL } }; size_t namlen = (5 + strlen (ni->name) + 1 + strlen (fct_name) + 1); char name[namlen]; /* Construct the function name. */ __stpcpy (__stpcpy (__stpcpy (name, ni->name), "_"), fct_name); result = NULL; for (tp = &tbl[0]; tp->fname; tp++) if (strcmp (tp->fname, name) == 0) { result = tp->fp; break; } } #endif /* Remember function pointer for later calls. Even if null, we record it so a second try needn't search the library again. */ known->fct_ptr = result; PTR_MANGLE (known->fct_ptr); } } /* Remove the lock. */ unlock_nsswitch; return result; } libc_hidden_def (__nss_lookup_function) #else /* below if ! __OPTION_EGLIBC_NSSWITCH */ int __nss_configure_lookup (const char *dbname, const char *service_line) { /* We can't dynamically configure lookup without OPTION_EGLIBC_NSSWITCH. */ __set_errno (EINVAL); return -1; } void * __nss_lookup_function (service_user *ni, const char *fct_name) { int i; const known_function **known = ni->known.array; for (i = 0; known[i]; i++) if (strcmp (fct_name, known[i]->fct_name) == 0) return known[i]->fct_ptr; return NULL; } libc_hidden_def (__nss_lookup_function) #endif #if __OPTION_EGLIBC_NSSWITCH static name_database * internal_function nss_parse_file (const char *fname) { FILE *fp; name_database *result; name_database_entry *last; char *line; size_t len; /* Open the configuration file. */ fp = fopen (fname, "rce"); if (fp == NULL) return NULL; /* No threads use this stream. */ __fsetlocking (fp, FSETLOCKING_BYCALLER); result = (name_database *) malloc (sizeof (name_database)); if (result == NULL) { fclose (fp); return NULL; } result->entry = NULL; result->library = NULL; last = NULL; line = NULL; len = 0; do { name_database_entry *this; ssize_t n; n = __getline (&line, &len, fp); if (n < 0) break; if (line[n - 1] == '\n') line[n - 1] = '\0'; /* Because the file format does not know any form of quoting we can search forward for the next '#' character and if found make it terminating the line. */ *__strchrnul (line, '#') = '\0'; /* If the line is blank it is ignored. */ if (line[0] == '\0') continue; /* Each line completely specifies the actions for a database. */ this = nss_getline (line); if (this != NULL) { if (last != NULL) last->next = this; else result->entry = this; last = this; } } while (!feof_unlocked (fp)); /* Free the buffer. */ free (line); /* Close configuration file. */ fclose (fp); return result; } /* Read the source names: `( ( "[" "!"? ( "=" )+ "]" )? )*' */ static service_user * internal_function nss_parse_service_list (const char *line) { service_user *result = NULL, **nextp = &result; while (1) { service_user *new_service; const char *name; while (isspace (line[0])) ++line; if (line[0] == '\0') /* No source specified. */ return result; /* Read identifier. */ name = line; while (line[0] != '\0' && !isspace (line[0]) && line[0] != '[') ++line; if (name == line) return result; new_service = (service_user *) malloc (sizeof (service_user) + (line - name + 1)); if (new_service == NULL) return result; new_service->name = (char *) (new_service + 1); *((char *) __mempcpy ((char *) new_service->name, name, line - name)) = '\0'; /* Set default actions. */ new_service->actions[2 + NSS_STATUS_TRYAGAIN] = NSS_ACTION_CONTINUE; new_service->actions[2 + NSS_STATUS_UNAVAIL] = NSS_ACTION_CONTINUE; new_service->actions[2 + NSS_STATUS_NOTFOUND] = NSS_ACTION_CONTINUE; new_service->actions[2 + NSS_STATUS_SUCCESS] = NSS_ACTION_RETURN; new_service->actions[2 + NSS_STATUS_RETURN] = NSS_ACTION_RETURN; new_service->library = NULL; new_service->known.tree = NULL; new_service->next = NULL; while (isspace (line[0])) ++line; if (line[0] == '[') { /* Read criterions. */ do ++line; while (line[0] != '\0' && isspace (line[0])); do { int not; enum nss_status status; lookup_actions action; /* Grok ! before name to mean all statii but that one. */ not = line[0] == '!'; if (not) ++line; /* Read status name. */ name = line; while (line[0] != '\0' && !isspace (line[0]) && line[0] != '=' && line[0] != ']') ++line; /* Compare with known statii. */ if (line - name == 7) { if (__strncasecmp (name, "SUCCESS", 7) == 0) status = NSS_STATUS_SUCCESS; else if (__strncasecmp (name, "UNAVAIL", 7) == 0) status = NSS_STATUS_UNAVAIL; else goto finish; } else if (line - name == 8) { if (__strncasecmp (name, "NOTFOUND", 8) == 0) status = NSS_STATUS_NOTFOUND; else if (__strncasecmp (name, "TRYAGAIN", 8) == 0) status = NSS_STATUS_TRYAGAIN; else goto finish; } else goto finish; while (isspace (line[0])) ++line; if (line[0] != '=') goto finish; do ++line; while (isspace (line[0])); name = line; while (line[0] != '\0' && !isspace (line[0]) && line[0] != '=' && line[0] != ']') ++line; if (line - name == 6 && __strncasecmp (name, "RETURN", 6) == 0) action = NSS_ACTION_RETURN; else if (line - name == 8 && __strncasecmp (name, "CONTINUE", 8) == 0) action = NSS_ACTION_CONTINUE; else goto finish; if (not) { /* Save the current action setting for this status, set them all to the given action, and reset this one. */ const lookup_actions save = new_service->actions[2 + status]; new_service->actions[2 + NSS_STATUS_TRYAGAIN] = action; new_service->actions[2 + NSS_STATUS_UNAVAIL] = action; new_service->actions[2 + NSS_STATUS_NOTFOUND] = action; new_service->actions[2 + NSS_STATUS_SUCCESS] = action; new_service->actions[2 + status] = save; } else new_service->actions[2 + status] = action; /* Skip white spaces. */ while (isspace (line[0])) ++line; } while (line[0] != ']'); /* Skip the ']'. */ ++line; } *nextp = new_service; nextp = &new_service->next; continue; finish: free (new_service); return result; } } static name_database_entry * internal_function nss_getline (char *line) { const char *name; name_database_entry *result; size_t len; /* Ignore leading white spaces. ATTENTION: this is different from what is implemented in Solaris. The Solaris man page says a line beginning with a white space character is ignored. We regard this as just another misfeature in Solaris. */ while (isspace (line[0])) ++line; /* Recognize ` ":"'. */ name = line; while (line[0] != '\0' && !isspace (line[0]) && line[0] != ':') ++line; if (line[0] == '\0' || name == line) /* Syntax error. */ return NULL; *line++ = '\0'; len = strlen (name) + 1; result = (name_database_entry *) malloc (sizeof (name_database_entry) + len); if (result == NULL) return NULL; result->name = (char *) (result + 1); /* Save the database name. */ memcpy ((char *) result->name, name, len); /* Parse the list of services. */ result->service = nss_parse_service_list (line); result->next = NULL; return result; } static service_library * internal_function nss_new_service (name_database *database, const char *name) { service_library **currentp = &database->library; while (*currentp != NULL) { if (strcmp ((*currentp)->name, name) == 0) return *currentp; currentp = &(*currentp)->next; } /* We have to add the new service. */ *currentp = (service_library *) malloc (sizeof (service_library)); if (*currentp == NULL) return NULL; (*currentp)->name = name; (*currentp)->lib_handle = NULL; (*currentp)->next = NULL; return *currentp; } #endif /* __OPTION_EGLIBC_NSSWITCH */ #ifdef SHARED /* Load all libraries for the service. */ static void nss_load_all_libraries (const char *service, const char *def) { service_user *ni = NULL; if (__nss_database_lookup (service, NULL, def, &ni) == 0) while (ni != NULL) { nss_load_library (ni); ni = ni->next; } } #if __OPTION_EGLIBC_INET /* Called by nscd and nscd alone. */ void __nss_disable_nscd (void (*cb) (size_t, struct traced_file *)) { # ifdef PTR_MANGLE PTR_MANGLE (cb); # endif nscd_init_cb = cb; is_nscd = true; /* Find all the relevant modules so that the init functions are called. */ nss_load_all_libraries ("passwd", "compat [NOTFOUND=return] files"); nss_load_all_libraries ("group", "compat [NOTFOUND=return] files"); nss_load_all_libraries ("hosts", "dns [!UNAVAIL=return] files"); nss_load_all_libraries ("services", NULL); /* Disable all uses of NSCD. */ __nss_not_use_nscd_passwd = -1; __nss_not_use_nscd_group = -1; __nss_not_use_nscd_hosts = -1; __nss_not_use_nscd_services = -1; __nss_not_use_nscd_netgroup = -1; } #endif /* __OPTION_EGLIBC_INET */ #endif #if __OPTION_EGLIBC_NSSWITCH static void free_database_entries (name_database_entry *entry) { while (entry != NULL) { name_database_entry *olde = entry; service_user *service = entry->service; while (service != NULL) { service_user *olds = service; if (service->known.tree != NULL) __tdestroy (service->known.tree, free); service = service->next; free (olds); } entry = entry->next; free (olde); } } /* Free all resources if necessary. */ libc_freeres_fn (free_defconfig) { name_database_entry *entry = defconfig_entries; if (entry == NULL) /* defconfig was not used. */ return; /* Don't disturb ongoing other threads (if there are any). */ defconfig_entries = NULL; free_database_entries (entry); } libc_freeres_fn (free_mem) { name_database *top = service_table; service_library *library; if (top == NULL) /* Maybe we have not read the nsswitch.conf file. */ return; /* Don't disturb ongoing other threads (if there are any). */ service_table = NULL; free_database_entries (top->entry); library = top->library; while (library != NULL) { service_library *oldl = library; if (library->lib_handle && library->lib_handle != (void *) -1l) __libc_dlclose (library->lib_handle); library = library->next; free (oldl); } free (top); } #endif /* __OPTION_EGLIBC_NSSWITCH */