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authorUlrich Drepper <drepper@redhat.com>2000-05-08 04:50:45 +0000
committerUlrich Drepper <drepper@redhat.com>2000-05-08 04:50:45 +0000
commitd1c2a14cdfd71fea547c9ec0db7eff85991bdd11 (patch)
tree200fb3d55b6d160fec0cc21978851f589e48fc40 /nss/nss_db/db-open.c
parent93414bb97c8d4af09fbc6ed493e5c904f27a5173 (diff)
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Update.
2000-05-07 Mark Kettenis <kettenis@gnu.org> * nss/nss_db/db-open.c: Cleanup and add comments. Pretty print. Remove duplicate <errno.h> include. Remove inclusion of <libintl.h> and "nsswitch.h". (set_cloexec_flag): New function, broken out of dbopen. (dbopen): Changed return type to `enum nss_status'. Mostly rewritten to make sure that we do not report NSS_STATUS_SUCCESS if something went wrong. Remove unnecessary casts. (internal_setent): Change return type to nss_status. Document, and make sure that the function behaves accordingly. Make dynamically loading the database library really thread-safe and return NSS_STATUS_UNAVAIL if it failed. (db_cursor): Return ENOMEM is memory allocation failed. Remove unecessary casts. * nss/nss_db/dummy-db.h: Add copyright notice. Improve documentation. (struct dbc24, struct dbc27): Use DBT type in parameter lists for c_get function member. * nss/nss_db/nss_db.h: Add and tweak some comments. (DBT): Move typedef before NSS_DBC typedef. (NSS_DBC, NSS_DB): Use DBT in function member parameter lists.
Diffstat (limited to 'nss/nss_db/db-open.c')
-rw-r--r--nss/nss_db/db-open.c299
1 files changed, 145 insertions, 154 deletions
diff --git a/nss/nss_db/db-open.c b/nss/nss_db/db-open.c
index 470af043a6..6a21a0af58 100644
--- a/nss/nss_db/db-open.c
+++ b/nss/nss_db/db-open.c
@@ -20,35 +20,42 @@
#include <errno.h>
#include <fcntl.h>
#include <dlfcn.h>
-#include <errno.h>
#include <stdlib.h>
-#include <libintl.h>
+#include <string.h>
#include <bits/libc-lock.h>
#include "dummy-db.h"
-#include "nsswitch.h"
#include "nss_db.h"
/* This file contains the functions used to open and close the databases
- read by the rest of libnss_db. They are not thread safe; the caller
- must handle locking.
+ read by the rest of libnss_db. Not all of them are thread safe;
+ make sure the caller does the appropriate locking.
We dynamically load the database library, so that it does not have
- to be present when glibc is compiled. Once loaded, libdb is never
- unloaded again unless this library is unloaded (from the free_mem
- routine in nsswitch.c) - we catch the unload by providing a shlib
- destructor. (XXX Does it work?) */
-
+ to be present when glibc is compiled. Once loaded, the database
+ library is never never unloaded again until the libnss_db module is
+ unloaded (from the free_mem routine in nsswitch.c) -- we catch the
+ unload by providing a shlib destructor. (XXX Does that actually
+ work?) */
+
+/* Handle for the shared Berkeley DB library. If non-null, the
+ database library is completely loaded and ready to be used by
+ multithreaded code. */
static void *libdb_handle;
+
+/* The version of the Berkeley DB library we are using. */
enum {
nodb,
db24,
db27,
db30
} libdb_version;
+
+/* Pointer to the db_open function. For use with DB 2.x. */
static int (*libdb_db_open) (const char *, int,
uint32_t, int, void *, void *, void **);
+/* Pointer to the db_create function. For use with DB 3.x. */
static int (*libdb_db_create) (void *, void *, uint32_t);
/* Constants which vary from version to version are actually variables
@@ -65,13 +72,17 @@ int db_notfound;
/* Locks the static variables in this file. */
__libc_lock_define_initialized (static, lock)
-/* Dynamically load the database library.
+/* Dynamically load the database library. Return zero if successful,
+ non-zero if no suitable version of the library could be loaded.
+ Must be called with the above lock held if it might run in a
+ multithreaded context.
+
We try currently:
- libdb.so.3: the name used by glibc 2.1
- libdb-3.0.so: the name used by db-3.0.x
and maybe others in the future. */
-
-int
+
+enum nss_status
load_db (void)
{
static const char *libnames[] = { "libdb.so.3", "libdb-3.0.so" };
@@ -83,11 +94,11 @@ load_db (void)
if (libdb_handle == NULL)
continue;
- /* db 3.0 has db_create instead of db_open. */
+ /* DB 3.0 has db_create instead of db_open. */
libdb_db_create = dlsym (libdb_handle, "db_create");
if (libdb_db_create == NULL)
- /* db 2.x uses db_open. */
+ /* DB 2.x uses db_open. */
libdb_db_open = dlsym (libdb_handle, "db_open");
if (libdb_db_open != NULL || libdb_db_create != NULL)
@@ -129,6 +140,7 @@ load_db (void)
db_rdonly = DB2x_RDONLY;
}
break;
+
case 3:
/* Sanity check: Do we have db_create? */
if (libdb_db_create != NULL)
@@ -141,12 +153,14 @@ load_db (void)
db_rdonly = DB30_RDONLY;
}
break;
+
default:
break;
}
}
+
if (libdb_version != nodb)
- return 0;
+ return NSS_STATUS_SUCCESS;
/* Clear variables. */
libdb_db_open = NULL;
@@ -157,7 +171,22 @@ load_db (void)
}
(void) dlerror ();
- return 1;
+ return NSS_STATUS_UNAVAIL;
+}
+
+/* Set the `FD_CLOEXEC' flag of FD. Return 0 on success, or -1 on
+ error with `errno' set. */
+static int
+set_cloexec_flag (int fd)
+{
+ int oldflags = fcntl (fd, F_GETFD, 0);
+
+ if (oldflags < 0)
+ return oldflags;
+
+ oldflags |= FD_CLOEXEC;
+
+ return fcntl (fd, F_SETFD, oldflags);
}
/* Make sure we don't use the library anymore once we are shutting down. */
@@ -173,6 +202,9 @@ unload_db (void)
}
}
+/* Open the database stored in FILE. If succesful, store the database
+ handle in *DBP and return NSS_STATUS_SUCCESS. On failure, return
+ the appropriate lookup status. */
enum nss_status
internal_setent (const char *file, NSS_DB **dbp)
{
@@ -184,26 +216,26 @@ internal_setent (const char *file, NSS_DB **dbp)
{
__libc_lock_lock (lock);
- status = load_db ();
+ if (libdb_db_open == NULL && libdb_db_create == NULL)
+ status = load_db ();
__libc_lock_unlock (lock);
-
- if (status != 0)
- return status;
}
- status = dbopen (file, db_rdonly, 0, dbp);
+ if (status == NSS_STATUS_SUCCESS)
+ status = dbopen (file, db_rdonly, 0, dbp);
}
return status;
}
-/* Close the database file. */
+/* Close the database *DBP. */
void
internal_endent (NSS_DB **dbp)
{
NSS_DB *db = *dbp;
+
if (db != NULL)
{
DL_CALL_FCT (db->close, (db->db, 0));
@@ -211,188 +243,147 @@ internal_endent (NSS_DB **dbp)
}
}
+/* Allocate a cursor for database DB and transaction TXN. On success,
+ store the cursor in *DBCP and return zero. Otherwise return an
+ error value. */
int
db_cursor (void *db, void *txn, NSS_DBC **dbcp)
{
- void *ptr;
- NSS_DBC *dbc = NULL;
+ NSS_DBC *dbc;
int ret;
+ dbc = (NSS_DBC *) malloc (sizeof (NSS_DBC));
+ if (dbc == NULL)
+ return ENOMEM;
+
switch (libdb_version)
{
case db24:
- ret = ((struct db24 *) db)->cursor (db, txn, &ptr);
+ ret = ((struct db24 *) db)->cursor (db, txn, &dbc->cursor);
+
+ if (ret == 0)
+ dbc->c_get = ((struct dbc24 *) dbc->cursor)->c_get;
break;
+
case db27:
- ret = ((struct db27 *) db)->cursor (db, txn, &ptr, 0);
+ ret = ((struct db27 *) db)->cursor (db, txn, &dbc->cursor, 0);
+
+ if (ret == 0)
+ dbc->c_get = ((struct dbc27 *) dbc->cursor)->c_get;
break;
+
case db30:
- ret = ((struct db30 *) db)->cursor (db, txn, &ptr, 0);
+ ret = ((struct db30 *) db)->cursor (db, txn, &dbc->cursor, 0);
+
+ if (ret == 0)
+ dbc->c_get = ((struct dbc30 *) dbc->cursor)->c_get;
break;
+
default:
abort ();
}
- if (ret == 0)
+ if (ret != 0)
{
- dbc = (NSS_DBC *) malloc (sizeof (NSS_DBC));
- if (dbc == NULL)
- return 1;
- dbc->cursor = ptr;
-
- switch (libdb_version)
- {
- case db24:
- dbc->c_get =
- (int (*) (void *, void *, void *, uint32_t))
- ((struct dbc24 *) ptr)->c_get;
- break;
- case db27:
- dbc->c_get =
- (int (*) (void *, void *, void *, uint32_t))
- ((struct dbc27 *) ptr)->c_get;
- break;
- case db30:
- dbc->c_get =
- (int (*) (void *, void *, void *, uint32_t))
- ((struct dbc30 *) ptr)->c_get;
- default:
- abort ();
- }
+ free (dbc);
+ return ret;
}
*dbcp = dbc;
- return ret;
+ return 0;
}
+/* Open the database in FNAME, for access specified by FLAGS. If
+ opening the database causes the file FNAME to be created, it is
+ created with MODE. If succesful, store the database handle in *DBP
+ and return NSS_STATUS_SUCCESS. On failure, return the appropriate
+ lookup status. */
int
dbopen (const char *fname, int oper, int mode, NSS_DB **dbp)
{
int err;
- int result;
int fd;
- void *odb;
- enum nss_status status = NSS_STATUS_SUCCESS;
NSS_DB *db;
+ /* Construct the object we pass up. */
+ db = (NSS_DB *) calloc (1, sizeof (NSS_DB));
+ if (db == NULL)
+ return NSS_STATUS_UNAVAIL;
+
+ /* Initialize the object. */
+ db->cursor = db_cursor;
+
/* Actually open the database. */
switch (libdb_version)
{
case db24:
case db27:
err = DL_CALL_FCT (libdb_db_open,
- (fname, DB_BTREE, oper, mode, NULL, NULL, &odb));
+ (fname, DB_BTREE, oper, mode, NULL, NULL, &db->db));
if (err != 0)
+ goto fail;
+
+ if (libdb_version)
{
- __set_errno (err);
- *dbp = NULL;
- return err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
+ db->close = ((struct db24 *) db->db)->close;
+ db->fd = ((struct db24 *) db->db)->fd;
+ db->get = ((struct db24 *) db->db)->get;
+ db->put = ((struct db24 *) db->db)->put;
+ }
+ else
+ {
+ db->close = ((struct db27 *) db->db)->close;
+ db->fd = ((struct db27 *) db->db)->fd;
+ db->get = ((struct db27 *) db->db)->get;
+ db->put = ((struct db27 *) db->db)->put;
}
break;
+
case db30:
- err = DL_CALL_FCT (libdb_db_create, (&odb, NULL, 0));
+ err = DL_CALL_FCT (libdb_db_create, (db->db, NULL, 0));
if (err != 0)
- {
- __set_errno (err);
- *dbp = NULL;
- return err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
- }
- err = ((struct db30 *) odb)->open (odb, fname, NULL, DB_BTREE,
- oper, mode);
+ goto fail;
+
+ db->close = ((struct db30 *) db->db)->close;
+ db->fd = ((struct db30 *) db->db)->fd;
+ db->get = ((struct db30 *) db->db)->get;
+ db->put = ((struct db30 *) db->db)->put;
+
+ err = ((struct db30 *) db->db)->open (db->db, fname, NULL, DB_BTREE,
+ oper, mode);
if (err != 0)
- {
- __set_errno (err);
- /* Free all resources. */
- ((struct db30 *) odb)->close (odb, 0);
- *dbp = NULL;
- return NSS_STATUS_UNAVAIL;
- }
+ goto fail;
break;
+
default:
abort ();
}
-
- /* Construct the object we pass up. */
- db = (NSS_DB *) malloc (sizeof (NSS_DB));
- if (db != NULL)
- {
- db->db = odb;
- /* The functions are at different positions for the different
- versions. Sigh. */
- switch (libdb_version)
- {
- case db24:
- db->close =
- (int (*) (void *, uint32_t)) ((struct db24 *) odb)->close;
- db->fd =
- (int (*) (void *, int *)) ((struct db24 *) odb)->fd;
- db->get =
- (int (*) (void *, void *, void *, void *, uint32_t))
- ((struct db24 *) odb)->get;
- db->put =
- (int (*) (void *, void *, void *, void *, uint32_t))
- ((struct db24 *) odb)->put;
- break;
- case db27:
- db->close =
- (int (*) (void *, uint32_t)) ((struct db27 *) odb)->close;
- db->fd =
- (int (*) (void *, int *)) ((struct db27 *) odb)->fd;
- db->get =
- (int (*) (void *, void *, void *, void *, uint32_t))
- ((struct db27 *) odb)->get;
- db->put =
- (int (*) (void *, void *, void *, void *, uint32_t))
- ((struct db27 *) odb)->put;
- break;
- case db30:
- db->close =
- (int (*) (void *, uint32_t)) ((struct db30 *) odb)->close;
- db->fd =
- (int (*) (void *, int *)) ((struct db30 *) odb)->fd;
- db->get =
- (int (*) (void *, void *, void *, void *, uint32_t))
- ((struct db30 *) odb)->get;
- db->put =
- (int (*) (void *, void *, void *, void *, uint32_t))
- ((struct db30 *) odb)->put;
- break;
- default:
- abort ();
- }
- db->cursor = db_cursor;
+ /* We have to make sure the file is `closed on exec'. */
+ err = DL_CALL_FCT (db->fd, (db->db, &fd));
+ if (err != 0)
+ goto fail;
+ if (set_cloexec_flag (fd) < 0)
+ goto fail;
- /* We have to make sure the file is `closed on exec'. */
- err = DL_CALL_FCT (db->fd, (odb, &fd));
- if (err != 0)
- {
- __set_errno (err);
- result = -1;
- }
- else
- {
- int flags = result = fcntl (fd, F_GETFD, 0);
+ *dbp = db;
- if (result >= 0)
- {
- flags |= FD_CLOEXEC;
- result = fcntl (fd, F_SETFD, flags);
- }
- }
- if (result < 0)
- {
- /* Something went wrong. Close the stream and return a
- failure. */
- DL_CALL_FCT (db->close, (odb, 0));
- free (db);
- status = NSS_STATUS_UNAVAIL;
- db = NULL;
- }
+ return NSS_STATUS_UNAVAIL;
+
+ fail:
+ /* Something went wrong. Close the database if necessary. */
+ if (db)
+ {
+ if (db->db && db->close)
+ DL_CALL_FCT (db->close, (db->db, 0));
+ free (db);
}
- *dbp = db;
-
- return status;
+
+ /* Make sure `errno' is set. */
+ if (err)
+ __set_errno (err);
+
+ return err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
}