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-rw-r--r--nss/nsswitch.c116
1 files changed, 86 insertions, 30 deletions
diff --git a/nss/nsswitch.c b/nss/nsswitch.c
index 1349e0c..0a4c948 100644
--- a/nss/nsswitch.c
+++ b/nss/nsswitch.c
@@ -19,6 +19,7 @@ Boston, MA 02111-1307, USA. */
#include <ctype.h>
#include <dlfcn.h>
+#include <errno.h>
#include <netdb.h>
#include <libc-lock.h>
#include <search.h>
@@ -30,7 +31,6 @@ Boston, MA 02111-1307, USA. */
#include "../elf/link.h" /* We need some help from ld.so. */
/* Prototypes for the local functions. */
-static void nss_init (void);
static void *nss_lookup_function (service_user *ni, const char *fct_name);
static name_database *nss_parse_file (const char *fname);
static name_database_entry *nss_getline (char *line);
@@ -39,6 +39,27 @@ static service_library *nss_new_service (name_database *database,
const char *name);
+/* Declare external database variables. */
+#define DEFINE_DATABASE(name) \
+ extern service_user *__nss_##name##_database; \
+ weak_extern (__nss_##name##_database)
+#include "databases.def"
+#undef DEFINE_DATABASE
+
+/* Structure to map database name to variable. */
+static struct
+{
+ const char *name;
+ service_user **dbp;
+} databases[] =
+{
+#define DEFINE_DATABASE(name) \
+ { #name, &__nss_##name##_database },
+#include "databases.def"
+#undef DEFINE_DATABASE
+};
+
+
__libc_lock_define_initialized (static, lock)
@@ -50,35 +71,29 @@ static int nss_initialized;
static name_database *service_table;
-static void
-nss_init (void)
-{
- /* Prevent multiple threads to change the service table. */
- __libc_lock_lock (lock);
-
- if (service_table == NULL)
- service_table = nss_parse_file (_PATH_NSSWITCH_CONF);
-
- __libc_lock_unlock (lock);
-}
-
-
/* -1 == database not found
0 == database entry pointer stored */
int
__nss_database_lookup (const char *database, const char *defconfig,
service_user **ni)
{
- name_database_entry *entry;
+ /* Prevent multiple threads to change the service table. */
+ __libc_lock_lock (lock);
- if (nss_initialized == 0)
- nss_init ();
+ /* Reconsider database variable in case some other thread called
+ `__nss_configure_lookup' while we waited for the lock. */
+ if (*ni != NULL)
+ return 0;
+
+ if (nss_initialized == 0 && service_table == NULL)
+ /* Read config file. */
+ service_table = nss_parse_file (_PATH_NSSWITCH_CONF);
/* Test whether configuration data is available. */
- if (service_table)
+ if (service_table != NULL)
{
- /* Return first `service_user' entry for DATABASE.
- XXX Will use perfect hashing function for known databases. */
+ /* 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. */
@@ -91,17 +106,14 @@ __nss_database_lookup (const char *database, const char *defconfig,
}
/* No configuration data is available, either because nsswitch.conf
- doesn't exist or because it doesn't have a line for this database. */
- entry = malloc (sizeof *entry);
- if (entry == NULL)
- return -1;
- entry->name = database;
- /* DEFCONFIG specifies the default service list for this database,
+ doesn't exist or because it doesn't has a line for this database.
+
+ DEFCONFIG specifies the default service list for this database,
or null to use the most common default. */
- entry->service = nss_parse_service_list (defconfig ?:
- "compat [NOTFOUND=return] files");
+ *ni = nss_parse_service_list (defconfig ?: "compat [NOTFOUND=return] files");
+
+ __libc_lock_unlock (lock);
- *ni = entry->service;
return 0;
}
@@ -168,6 +180,48 @@ __nss_next (service_user **ni, const char *fct_name, void **fctp, int status,
}
+int
+__nss_configure_lookup (const char *dbname, const char *service_line)
+{
+ service_user *new_db;
+ size_t cnt;
+
+ for (cnt = 0; cnt < sizeof databases; ++cnt)
+ if (strcmp (dbname, databases[cnt].name) == 0)
+ break;
+
+ if (cnt == sizeof databases)
+ {
+ 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. */
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* Prevent multiple threads to change the service table. */
+ __libc_lock_lock (lock);
+
+ /* Install new rules. */
+ *databases[cnt].dbp = new_db;
+
+ __libc_lock_unlock (lock);
+
+ return 0;
+}
+
+
static int
nss_dlerror_run (void (*operate) (void))
{
@@ -385,7 +439,9 @@ nss_parse_file (const char *fname)
}
-/* Read the source names: `<source> ( "[" <status> "=" <action> "]" )*'. */
+/* Read the source names:
+ `( <source> ( "[" "!"? (<status> "=" <action> )+ "]" )? )*'
+ */
static service_user *
nss_parse_service_list (const char *line)
{