diff options
Diffstat (limited to 'nss/nss_db/db-open.c')
| -rw-r--r-- | nss/nss_db/db-open.c | 377 |
1 files changed, 30 insertions, 347 deletions
diff --git a/nss/nss_db/db-open.c b/nss/nss_db/db-open.c index 94dfe5b7da..36ce494d02 100644 --- a/nss/nss_db/db-open.c +++ b/nss/nss_db/db-open.c @@ -1,5 +1,5 @@ /* Common database routines for nss_db. - Copyright (C) 2000 Free Software Foundation, Inc. + Copyright (C) 2000, 2011 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 @@ -22,368 +22,51 @@ #include <dlfcn.h> #include <stdlib.h> #include <string.h> -#include <bits/libc-lock.h> +#include <sys/mman.h> +#include <not-cancel.h> -#include "dummy-db.h" +#include <kernel-features.h> #include "nss_db.h" -/* This file contains the functions used to open and close the databases - 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, 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 - here. */ -int db_first; -int db_next; -int db_nooverwrite; -int db_truncate; -int db_rdonly; -/* Variables which keep track of the error values. */ -int db_keyexist; -int db_notfound; - -/* Locks the static variables in this file. */ -__libc_lock_define_initialized (static, lock) - -/* 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. */ - +/* Open the database stored in FILE. If succesful, store either a + pointer to the mapped file or a file handle for the file in H and + return NSS_STATUS_SUCCESS. On failure, return the appropriate + lookup status. */ enum nss_status -load_db (void) -{ - static const char *libnames[] = { "libdb.so.3", "libdb-3.0.so" }; - int x; - - for (x = 0; x < sizeof (libnames) / sizeof (libnames[0]); ++x) - { - libdb_handle = dlopen (libnames[x], RTLD_LAZY); - if (libdb_handle == NULL) - continue; - - /* 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. */ - libdb_db_open = dlsym (libdb_handle, "db_open"); - - if (libdb_db_open != NULL || libdb_db_create != NULL) - { - /* 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)); - switch (major) - { - case 2: - /* Sanity check: Do we have db_open? */ - if (libdb_db_open != NULL) - { - if (minor < 6 || (minor == 6 && subminor < 4)) - { - libdb_version = db24; - db_first = DB24_FIRST; - db_next = DB24_NEXT; - db_nooverwrite = DB24_NOOVERWRITE; - db_truncate = DB24_TRUNCATE; - } - else - { - libdb_version = db27; - db_first = DB27_FIRST; - db_next = DB27_NEXT; - db_nooverwrite = DB27_NOOVERWRITE; - db_truncate = DB27_TRUNCATE; - } - db_keyexist = DB2x_KEYEXIST; - db_notfound = DB2x_NOTFOUND; - db_rdonly = DB2x_RDONLY; - } - break; - - case 3: - /* Sanity check: Do we have db_create? */ - if (libdb_db_create != NULL) - { - libdb_version = db30; - db_first = DB30_FIRST; - db_next = DB30_NEXT; - db_keyexist = DB30_KEYEXIST; - db_notfound = DB30_NOTFOUND; - db_rdonly = DB30_RDONLY; - } - break; - - default: - break; - } - } - - if (libdb_version != nodb) - return NSS_STATUS_SUCCESS; - - /* Clear variables. */ - libdb_db_open = NULL; - libdb_db_create = NULL; - } - - dlclose (libdb_handle); - } - - (void) dlerror (); - 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) +internal_setent (const char *file, struct nss_db_map *mapping) { - 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. */ -static void __attribute__ ((destructor)) -unload_db (void) -{ - if (libdb_handle != NULL) + enum nss_status status = NSS_STATUS_UNAVAIL; + + int mode = O_RDONLY | O_LARGEFILE; +#ifdef O_CLOEXEC + mode |= O_CLOEXEC; +#endif + int fd = open_not_cancel_2 (file, mode); + if (fd != -1) { - libdb_db_open = NULL; - libdb_db_create = NULL; - libdb_version = nodb; - dlclose (libdb_handle); - } -} - -/* 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) -{ - enum nss_status status = NSS_STATUS_SUCCESS; + struct nss_db_header header; - if (*dbp == NULL) - { - if (libdb_db_open == NULL && libdb_db_create == NULL) + if (read (fd, &header, sizeof (header)) == sizeof (header)) { - __libc_lock_lock (lock); - - if (libdb_db_open == NULL && libdb_db_create == NULL) - status = load_db (); - - __libc_lock_unlock (lock); + mapping->header = mmap (NULL, header.allocate, PROT_READ, + MAP_PRIVATE, fd, 0); + mapping->len = header.allocate; + if (mapping->header != MAP_FAILED) + status = NSS_STATUS_SUCCESS; + else if (errno == ENOMEM) + status = NSS_STATUS_TRYAGAIN; } - if (status == NSS_STATUS_SUCCESS) - status = dbopen (file, db_rdonly, 0, dbp); + close_not_cancel_no_status (fd); } return status; } -/* Close the database *DBP. */ +/* Close the database. */ void -internal_endent (NSS_DB **dbp) -{ - NSS_DB *db = *dbp; - - if (db != NULL) - { - DL_CALL_FCT (db->close, (db->db, 0)); - *dbp = NULL; - } -} - -/* 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) -{ - 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, &dbc->cursor); - - if (ret == 0) - dbc->c_get = ((struct dbc24 *) dbc->cursor)->c_get; - break; - - case db27: - 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, &dbc->cursor, 0); - - if (ret == 0) - dbc->c_get = ((struct dbc30 *) dbc->cursor)->c_get; - break; - - default: - abort (); - } - - if (ret != 0) - { - free (dbc); - return ret; - } - - *dbcp = dbc; - - 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) +internal_endent (struct nss_db_map *mapping) { - int err; - int fd; - 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, &db->db)); - if (err != 0) - goto fail; - - if (libdb_version) - { - 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, (db->db, NULL, 0)); - if (err != 0) - 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) - goto fail; - break; - - default: - abort (); - } - - /* 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; - - *dbp = db; - - 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); - } - - /* Make sure `errno' is set. */ - if (err) - __set_errno (err); - - return err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL; + munmap (mapping->header, mapping->len); } |