diff options
Diffstat (limited to 'nss/nss_db/db-open.c')
| -rw-r--r-- | nss/nss_db/db-open.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/nss/nss_db/db-open.c b/nss/nss_db/db-open.c new file mode 100644 index 0000000000..2d96ffdd1b --- /dev/null +++ b/nss/nss_db/db-open.c @@ -0,0 +1,229 @@ +/* Common database open/close routines for nss_db. + Copyright (C) 1999, 2000 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <fcntl.h> +#include <dlfcn.h> +#include <errno.h> +#include <stdlib.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. + + 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?) */ + +static void *libdb_handle; +enum { + nodb, + db24, + db27 +} libdb_version; +static int (*libdb_db_open) (const char *, int, + uint32_t, int, void *, void *, void **); + +/* Locks the static variables in this file. */ +__libc_lock_define_initialized (static, lock) + +/* Dynamically load the database library. + We try libdb2.so.3, maybe others in the future. */ +static int +load_db (void) +{ + static const char *libnames[] = { "libdb.so.3" }; + int x; + + for(x = 0; x < 1; ++x) + { + libdb_handle = dlopen (libnames[x], RTLD_LAZY); + if (libdb_handle == NULL) + continue; + + libdb_db_open = dlsym (libdb_handle, "db_open"); + if (libdb_db_open) + { + /* Alright, we got a library. Now find out which version it is. */ + const char *(*db_version) (int *, int *, int *); + + db_version = dlsym (libdb_handle, "db_version"); + if (db_version != NULL) + { + /* Call the function and get the information. */ + int major, minor, subminor; + + DL_CALL_FCT (db_version, (&major, &minor, &subminor)); + if (major == 2) + { + /* We currently cannot handle other versions than the + 2.x series. */ + if (minor < 6 || (minor == 6 && subminor < 4)) + libdb_version = db24; + else + libdb_version = db27; + } + } + + if (libdb_version != nodb) + return 0; + } + + dlclose (libdb_handle); + } + + (void) dlerror (); + return 1; +} + + +/* Make sure we don't use the library anymore once we are shutting down. */ +static void __attribute__ ((destructor)) +unload_db (void) +{ + if (libdb_handle != NULL) + { + libdb_db_open = NULL; + libdb_version = nodb; + dlclose (libdb_handle); + } +} + + +enum nss_status +internal_setent (const char *file, NSS_DB **dbp) +{ + enum nss_status status = NSS_STATUS_SUCCESS; + int err; + void *db; + + if (*dbp == NULL) + { + if (libdb_db_open == NULL) + { + __libc_lock_lock (lock); + + err = load_db (); + + __libc_lock_unlock (lock); + + if (err != 0) + return NSS_STATUS_UNAVAIL; + } + + /* Open the database. Fortunately this interface seems to be the + same for all supported versions. */ + err = DL_CALL_FCT (libdb_db_open, + (file, DB_BTREE, DB_RDONLY, 0, NULL, NULL, &db)); + + /* Construct the object we pass up. */ + *dbp = (NSS_DB *) malloc (sizeof (NSS_DB)); + if (*dbp != NULL) + { + (*dbp)->db = db; + + /* The functions are at different positions for the different + versions. Sigh. */ + switch (libdb_version) + { + case db24: + (*dbp)->close = + (int (*) (void *, uint32_t)) ((struct db24 *) db)->close; + (*dbp)->fd = + (int (*) (void *, int *)) ((struct db24 *) db)->fd; + (*dbp)->get = + (int (*) (void *, void *, void *, void *, uint32_t)) + ((struct db24 *) db)->get; + break; + case db27: + (*dbp)->close = + (int (*) (void *, uint32_t)) ((struct db27 *) db)->close; + (*dbp)->fd = + (int (*) (void *, int *)) ((struct db27 *) db)->fd; + (*dbp)->get = + (int (*) (void *, void *, void *, void *, uint32_t)) + ((struct db27 *) db)->get; + break; + default: + abort (); + } + } + + if (err != 0) + { + __set_errno (err); + *dbp = NULL; + status = err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL; + } + else + { + /* We have to make sure the file is `closed on exec'. */ + int fd; + int result; + + err = DL_CALL_FCT ((*dbp)->fd, (db, &fd)); + if (err != 0) + { + __set_errno (err); + result = -1; + } + else + { + int flags = result = fcntl (fd, F_GETFD, 0); + + 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 ((*dbp)->close, (db, 0)); + status = NSS_STATUS_UNAVAIL; + } + + if (result < 0) + *dbp = NULL; + } + } + + return status; +} + + +/* Close the database file. */ +void +internal_endent (NSS_DB **dbp) +{ + NSS_DB *db = *dbp; + if (db != NULL) + { + DL_CALL_FCT (db->close, (db->db, 0)); + *dbp = NULL; + } +} |