krb5_error_code
osa_adb_open_and_lock(osa_adb_princ_t db, int locktype)
{
int ret;
ret = osa_adb_get_lock(db, locktype);
if (ret != OSA_ADB_OK)
return ret;
if (db->opencnt)
goto open_ok;
db->db = dbopen(db->filename, O_RDWR, 0600, DB_BTREE, &db->btinfo);
if (db->db != NULL)
goto open_ok;
if (IS_EFTYPE(errno)) {
db->db = dbopen(db->filename, O_RDWR, 0600, DB_HASH, &db->info);
if (db->db != NULL)
goto open_ok;
} else {
(void) osa_adb_release_lock(db);
if (errno == EINVAL)
return OSA_ADB_BAD_DB;
return errno;
}
open_ok:
db->opencnt++;
return OSA_ADB_OK;
}
krb5_error_code
osa_adb_rename_db(char *filefrom, char *lockfrom, char *fileto, char *lockto,
int magic)
{
osa_adb_db_t fromdb, todb;
krb5_error_code ret;
/* make sure todb exists */
if ((ret = osa_adb_create_db(fileto, lockto, magic)) &&
ret != EEXIST)
return ret;
if ((ret = osa_adb_init_db(&fromdb, filefrom, lockfrom, magic)))
return ret;
if ((ret = osa_adb_init_db(&todb, fileto, lockto, magic))) {
(void) osa_adb_fini_db(fromdb, magic);
return ret;
}
if ((ret = osa_adb_get_lock(fromdb, KRB5_DB_LOCKMODE_PERMANENT))) {
(void) osa_adb_fini_db(fromdb, magic);
(void) osa_adb_fini_db(todb, magic);
return ret;
}
if ((ret = osa_adb_get_lock(todb, KRB5_DB_LOCKMODE_PERMANENT))) {
(void) osa_adb_fini_db(fromdb, magic);
(void) osa_adb_fini_db(todb, magic);
return ret;
}
if ((rename(filefrom, fileto) < 0)) {
(void) osa_adb_fini_db(fromdb, magic);
(void) osa_adb_fini_db(todb, magic);
return errno;
}
/*
* Do not release the lock on fromdb because it is being renamed
* out of existence; no one can ever use it again.
*/
if ((ret = osa_adb_release_lock(todb))) {
(void) osa_adb_fini_db(fromdb, magic);
(void) osa_adb_fini_db(todb, magic);
return ret;
}
(void) osa_adb_fini_db(fromdb, magic);
(void) osa_adb_fini_db(todb, magic);
return 0;
}
static krb5_error_code
ctx_lock(krb5_context context, krb5_db2_context *dbc, int lockmode)
{
krb5_error_code retval;
int kmode, tries;
if (lockmode == KRB5_DB_LOCKMODE_PERMANENT ||
lockmode == KRB5_DB_LOCKMODE_EXCLUSIVE)
kmode = KRB5_LOCKMODE_EXCLUSIVE;
else if (lockmode == KRB5_DB_LOCKMODE_SHARED)
kmode = KRB5_LOCKMODE_SHARED;
else
return EINVAL;
if (dbc->db_locks_held == 0 || dbc->db_lock_mode < kmode) {
/* Acquire or upgrade the lock. */
for (tries = 0; tries < MAX_LOCK_TRIES; tries++) {
retval = krb5_lock_file(context, dbc->db_lf_file,
kmode | KRB5_LOCKMODE_DONTBLOCK);
if (retval == 0)
break;
if (retval == EBADF && kmode == KRB5_LOCKMODE_EXCLUSIVE)
/* Tried to lock something we don't have write access to. */
return KRB5_KDB_CANTLOCK_DB;
sleep(1);
}
if (retval == EACCES)
return KRB5_KDB_CANTLOCK_DB;
else if (retval == EAGAIN || retval == EWOULDBLOCK)
return OSA_ADB_CANTLOCK_DB;
else if (retval)
return retval;
/* Open the DB (or re-open it for read/write). */
if (dbc->db != NULL)
dbc->db->close(dbc->db);
dbc->db = open_db(dbc,
kmode == KRB5_LOCKMODE_SHARED ? O_RDONLY : O_RDWR,
0600);
if (dbc->db == NULL) {
retval = errno;
dbc->db_locks_held = 0;
dbc->db_lock_mode = 0;
(void) osa_adb_release_lock(dbc->policy_db);
(void) krb5_lock_file(context, dbc->db_lf_file,
KRB5_LOCKMODE_UNLOCK);
return retval;
}
dbc->db_lock_mode = kmode;
}
dbc->db_locks_held++;
/* Acquire or upgrade the policy lock. */
retval = osa_adb_get_lock(dbc->policy_db, lockmode);
if (retval)
(void) ctx_unlock(context, dbc);
return retval;
}
static krb5_error_code
ctx_lock(krb5_context context, krb5_db2_context *dbc, int lockmode)
{
krb5_error_code retval;
int kmode;
if (lockmode == KRB5_DB_LOCKMODE_PERMANENT ||
lockmode == KRB5_DB_LOCKMODE_EXCLUSIVE)
kmode = KRB5_LOCKMODE_EXCLUSIVE;
else if (lockmode == KRB5_DB_LOCKMODE_SHARED)
kmode = KRB5_LOCKMODE_SHARED;
else
return EINVAL;
if (dbc->db_locks_held == 0 || dbc->db_lock_mode < kmode) {
/* Acquire or upgrade the lock. */
retval = krb5_lock_file(context, dbc->db_lf_file, kmode);
/* Check if we tried to lock something not open for write. */
if (retval == EBADF && kmode == KRB5_LOCKMODE_EXCLUSIVE)
return KRB5_KDB_CANTLOCK_DB;
else if (retval == EACCES || retval == EAGAIN || retval == EWOULDBLOCK)
return KRB5_KDB_CANTLOCK_DB;
else if (retval)
return retval;
/* Open the DB (or re-open it for read/write). */
if (dbc->db != NULL)
dbc->db->close(dbc->db);
dbc->db = open_db(dbc,
kmode == KRB5_LOCKMODE_SHARED ? O_RDONLY : O_RDWR,
0600);
if (dbc->db == NULL) {
retval = errno;
dbc->db_locks_held = 0;
dbc->db_lock_mode = 0;
(void) osa_adb_release_lock(dbc->policy_db);
(void) krb5_lock_file(context, dbc->db_lf_file,
KRB5_LOCKMODE_UNLOCK);
return retval;
}
dbc->db_lock_mode = kmode;
}
dbc->db_locks_held++;
/* Acquire or upgrade the policy lock. */
retval = osa_adb_get_lock(dbc->policy_db, lockmode);
if (retval) {
(void) ctx_unlock(context, dbc);
if (retval == OSA_ADB_NOEXCL_PERM || retval == OSA_ADB_CANTLOCK_DB ||
retval == OSA_ADB_NOLOCKFILE)
retval = KRB5_KDB_CANTLOCK_DB;
}
return retval;
}
krb5_error_code
krb5_db2_lock(krb5_context context, int in_mode)
{
krb5_db2_context *db_ctx;
int krb5_lock_mode;
DB *db;
krb5_error_code retval;
time_t mod_time;
int mode, gotlock, tries;
switch (in_mode) {
case KRB5_DB_LOCKMODE_PERMANENT:
mode = KRB5_DB_LOCKMODE_EXCLUSIVE;
break;
case KRB5_DB_LOCKMODE_EXCLUSIVE:
mode = KRB5_LOCKMODE_EXCLUSIVE;
break;
case KRB5_DB_LOCKMODE_SHARED:
mode = KRB5_LOCKMODE_SHARED;
break;
default:
return EINVAL;
}
if (!k5db2_inited(context))
return KRB5_KDB_DBNOTINITED;
db_ctx = context->dal_handle->db_context;
if (db_ctx->db_locks_held && (db_ctx->db_lock_mode >= mode)) {
/* No need to upgrade lock, just return */
db_ctx->db_locks_held++;
goto policy_lock;
}
if ((mode != KRB5_LOCKMODE_SHARED) && (mode != KRB5_LOCKMODE_EXCLUSIVE))
return KRB5_KDB_BADLOCKMODE;
krb5_lock_mode = mode | KRB5_LOCKMODE_DONTBLOCK;
for (gotlock = tries = 0; tries < MAX_LOCK_TRIES; tries++) {
retval = krb5_lock_file(context, db_ctx->db_lf_file, krb5_lock_mode);
if (retval == 0) {
gotlock++;
break;
} else if (retval == EBADF && mode == KRB5_DB_LOCKMODE_EXCLUSIVE)
/* tried to exclusive-lock something we don't have */
/* write access to */
return KRB5_KDB_CANTLOCK_DB;
sleep(1);
}
if (retval == EACCES)
return KRB5_KDB_CANTLOCK_DB;
else if (retval == EAGAIN || retval == EWOULDBLOCK)
return OSA_ADB_CANTLOCK_DB;
else if (retval != 0)
return retval;
if ((retval = krb5_db2_get_age(context, NULL, &mod_time)))
goto lock_error;
db = k5db2_dbopen(db_ctx, db_ctx->db_name,
mode == KRB5_LOCKMODE_SHARED ? O_RDONLY : O_RDWR, 0600, db_ctx->tempdb);
if (db) {
db_ctx->db_lf_time = mod_time;
db_ctx->db = db;
} else {
retval = errno;
db_ctx->db = NULL;
goto lock_error;
}
db_ctx->db_lock_mode = mode;
db_ctx->db_locks_held++;
policy_lock:
if ((retval = osa_adb_get_lock(db_ctx->policy_db, in_mode))) {
krb5_db2_unlock(context);
}
return retval;
lock_error:;
db_ctx->db_lock_mode = 0;
db_ctx->db_locks_held = 0;
krb5_db2_unlock(context);
return retval;
}
/* Initialize dbc by locking and creating the DB. If the DB already exists,
* clear it out if dbc->tempdb is set; otherwise return EEXIST. */
static krb5_error_code
ctx_create_db(krb5_context context, krb5_db2_context *dbc)
{
krb5_error_code retval = 0;
char *dbname = NULL, *polname = NULL, *plockname = NULL;
retval = ctx_allfiles(dbc, &dbname, &dbc->db_lf_name, &polname,
&plockname);
if (retval)
return retval;
dbc->db_lf_file = open(dbc->db_lf_name, O_CREAT | O_RDWR | O_TRUNC,
0600);
if (dbc->db_lf_file < 0) {
retval = errno;
goto cleanup;
}
retval = krb5_lock_file(context, dbc->db_lf_file,
KRB5_LOCKMODE_EXCLUSIVE | KRB5_LOCKMODE_DONTBLOCK);
if (retval != 0)
goto cleanup;
set_cloexec_fd(dbc->db_lf_file);
dbc->db_lock_mode = KRB5_LOCKMODE_EXCLUSIVE;
dbc->db_locks_held = 1;
if (dbc->tempdb) {
/* Temporary DBs are locked for their whole lifetime. Since we have
* the lock, any remnant files can be safely destroyed. */
(void) destroy_file(dbname);
(void) unlink(polname);
(void) unlink(plockname);
}
dbc->db = open_db(dbc, O_RDWR | O_CREAT | O_EXCL, 0600);
if (dbc->db == NULL) {
retval = errno;
goto cleanup;
}
/* Create the policy database, initialize a handle to it, and lock it. */
retval = osa_adb_create_db(polname, plockname, OSA_ADB_POLICY_DB_MAGIC);
if (retval)
goto cleanup;
retval = osa_adb_init_db(&dbc->policy_db, polname, plockname,
OSA_ADB_POLICY_DB_MAGIC);
if (retval)
goto cleanup;
retval = osa_adb_get_lock(dbc->policy_db, KRB5_DB_LOCKMODE_EXCLUSIVE);
if (retval)
goto cleanup;
dbc->db_inited = 1;
cleanup:
if (retval) {
if (dbc->db != NULL)
dbc->db->close(dbc->db);
if (dbc->db_locks_held > 0) {
(void) krb5_lock_file(context, dbc->db_lf_file,
KRB5_LOCKMODE_UNLOCK);
}
if (dbc->db_lf_file >= 0)
close(dbc->db_lf_file);
ctx_clear(dbc);
}
free(dbname);
free(polname);
free(plockname);
return retval;
}
