int sem_close (sem_t *sem) { int result = 0; /* Get the lock. */ lll_lock (__sem_mappings_lock, LLL_PRIVATE); /* Locate the entry for the mapping the caller provided. */ rec = NULL; the_sem = sem; __twalk (__sem_mappings, walker); if (rec != NULL) { /* Check the reference counter. If it is going to be zero, free all the resources. */ if (--rec->refcnt == 0) { /* Remove the record from the tree. */ (void) __tdelete (rec, &__sem_mappings, __sem_search); result = munmap (rec->sem, sizeof (sem_t)); free (rec); } } else { /* This is no valid semaphore. */ result = -1; __set_errno (EINVAL); } /* Release the lock. */ lll_unlock (__sem_mappings_lock, LLL_PRIVATE); return result; }
void * __nss_lookup_function (service_user *ni, const char *fct_name) { void **found, *result; /* We now modify global data. Protect it. */ __libc_lock_lock (lock); /* 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, (void **) &ni->known, &known_compare); if (*found != &fct_name) /* The search found an existing structure in the tree. */ result = ((known_function *) *found)->fct_ptr; 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, (void **) &ni->known, &known_compare); result = NULL; } else { /* Point the tree node at this new structure. */ *found = known; known->fct_name = fct_name; 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) { /* This only happens when out of memory. */ free (known); goto remove_from_tree; } } #if !defined DO_STATIC_NSS || defined SHARED if (ni->library->lib_handle == NULL) { /* Load the shared library. */ size_t shlen = (7 + strlen (ni->library->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->library->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); } } 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->library->name) + 1 + strlen (fct_name) + 1); char name[namlen]; /* Construct the function name. */ __stpcpy (__stpcpy (__stpcpy (__stpcpy (name, "_nss_"), ni->library->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->library->name) + 1 + strlen (fct_name) + 1); char name[namlen]; /* Construct the function name. */ __stpcpy (__stpcpy (__stpcpy (name, ni->library->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; } } /* Remove the lock. */ __libc_lock_unlock (lock); return result; }