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;
}
