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https://github.com/samba-team/samba.git
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1e47a1b3f6
Signed-off-by: Martin Schwenke <martin@meltin.net> Reviewed-by: Amitay Isaacs <amitay@gmail.com>
348 lines
7.2 KiB
C
348 lines
7.2 KiB
C
/*
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ctdb lock helper
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Copyright (C) Amitay Isaacs 2013
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "replace.h"
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#include "system/filesys.h"
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#include "system/network.h"
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#include "system/wait.h"
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#include <talloc.h>
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#include <tevent.h>
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#include <tdb.h>
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#include "lib/util/sys_rw.h"
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#include "lib/util/tevent_unix.h"
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#include "protocol/protocol.h"
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#include "common/system.h"
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static bool realtime = true;
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struct lock_state {
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struct tdb_context *tdb;
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TDB_DATA key;
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};
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static void set_priority(void)
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{
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const char *ptr;
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ptr = getenv("CTDB_NOSETSCHED");
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if (ptr != NULL) {
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realtime = false;
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}
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if (! realtime) {
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return;
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}
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realtime = set_scheduler();
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if (! realtime) {
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fprintf(stderr,
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"locking: Unable to set real-time scheduler priority\n");
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}
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}
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static void reset_priority(void)
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{
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if (realtime) {
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reset_scheduler();
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}
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}
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static void send_result(int fd, char result)
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{
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sys_write(fd, &result, 1);
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if (result == 1) {
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exit(1);
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}
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}
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static void usage(const char *progname)
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{
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fprintf(stderr, "\n");
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fprintf(stderr, "Usage: %s <ctdbd-pid> <output-fd> RECORD <db-path> <db-flags> <db-key>\n", progname);
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fprintf(stderr, " %s <ctdbd-pid> <output-fd> DB <db-path> <db-flags>\n", progname);
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}
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static uint8_t *hex_decode_talloc(TALLOC_CTX *mem_ctx,
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const char *hex_in, size_t *len)
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{
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unsigned int i;
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int num;
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uint8_t *buffer;
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*len = strlen(hex_in) / 2;
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buffer = talloc_array(mem_ctx, unsigned char, *len);
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for (i=0; i<*len; i++) {
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sscanf(&hex_in[i*2], "%02X", &num);
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buffer[i] = (uint8_t)num;
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}
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return buffer;
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}
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static int lock_record(const char *dbpath, const char *dbflags,
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const char *dbkey, struct lock_state *state)
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{
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int tdb_flags;
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/* No error checking since CTDB always passes sane values */
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tdb_flags = strtol(dbflags, NULL, 0);
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/* Convert hex key to key */
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if (strcmp(dbkey, "NULL") == 0) {
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state->key.dptr = NULL;
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state->key.dsize = 0;
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} else {
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state->key.dptr = hex_decode_talloc(NULL, dbkey,
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&state->key.dsize);
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}
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state->tdb = tdb_open(dbpath, 0, tdb_flags, O_RDWR, 0600);
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if (state->tdb == NULL) {
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fprintf(stderr, "locking: Error opening database %s\n", dbpath);
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return 1;
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}
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set_priority();
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if (tdb_chainlock(state->tdb, state->key) < 0) {
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fprintf(stderr, "locking: Error getting record lock (%s)\n",
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tdb_errorstr(state->tdb));
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return 1;
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}
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reset_priority();
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return 0;
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}
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static int lock_db(const char *dbpath, const char *dbflags,
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struct lock_state *state)
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{
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int tdb_flags;
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/* No error checking since CTDB always passes sane values */
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tdb_flags = strtol(dbflags, NULL, 0);
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state->tdb = tdb_open(dbpath, 0, tdb_flags, O_RDWR, 0600);
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if (state->tdb == NULL) {
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fprintf(stderr, "locking: Error opening database %s\n", dbpath);
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return 1;
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}
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set_priority();
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if (tdb_lockall(state->tdb) < 0) {
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fprintf(stderr, "locking: Error getting db lock (%s)\n",
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tdb_errorstr(state->tdb));
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return 1;
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}
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reset_priority();
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return 0;
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}
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struct wait_for_parent_state {
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struct tevent_context *ev;
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pid_t ppid;
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};
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static void wait_for_parent_check(struct tevent_req *subreq);
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static struct tevent_req *wait_for_parent_send(TALLOC_CTX *mem_ctx,
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struct tevent_context *ev,
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pid_t ppid)
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{
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struct tevent_req *req, *subreq;
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struct wait_for_parent_state *state;
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req = tevent_req_create(mem_ctx, &state, struct wait_for_parent_state);
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if (req == NULL) {
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return NULL;
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}
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state->ev = ev;
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state->ppid = ppid;
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if (ppid == 1) {
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tevent_req_done(req);
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return tevent_req_post(req, ev);
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}
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subreq = tevent_wakeup_send(state, ev,
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tevent_timeval_current_ofs(5,0));
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if (tevent_req_nomem(subreq, req)) {
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return tevent_req_post(req, ev);
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}
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tevent_req_set_callback(subreq, wait_for_parent_check, req);
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return req;
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}
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static void wait_for_parent_check(struct tevent_req *subreq)
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{
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struct tevent_req *req = tevent_req_callback_data(
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subreq, struct tevent_req);
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struct wait_for_parent_state *state = tevent_req_data(
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req, struct wait_for_parent_state);
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bool status;
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status = tevent_wakeup_recv(subreq);
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TALLOC_FREE(subreq);
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if (! status) {
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/* Ignore error */
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fprintf(stderr, "locking: tevent_wakeup_recv() failed\n");
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}
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if (kill(state->ppid, 0) == -1 && errno == ESRCH) {
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tevent_req_done(req);
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return;
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}
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subreq = tevent_wakeup_send(state, state->ev,
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tevent_timeval_current_ofs(5,0));
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if (tevent_req_nomem(subreq, req)) {
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return;
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}
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tevent_req_set_callback(subreq, wait_for_parent_check, req);
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}
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static bool wait_for_parent_recv(struct tevent_req *req)
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{
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if (tevent_req_is_unix_error(req, NULL)) {
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return false;
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}
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return true;
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}
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static void cleanup(struct lock_state *state)
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{
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if (state->tdb != NULL) {
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if (state->key.dsize == 0) {
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tdb_unlockall(state->tdb);
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} else {
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tdb_chainunlock(state->tdb, state->key);
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}
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tdb_close(state->tdb);
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}
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}
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static void signal_handler(struct tevent_context *ev,
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struct tevent_signal *se,
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int signum, int count, void *siginfo,
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void *private_data)
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{
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struct lock_state *state = (struct lock_state *)private_data;
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cleanup(state);
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exit(0);
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}
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int main(int argc, char *argv[])
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{
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struct tevent_context *ev;
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struct tevent_signal *se;
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struct tevent_req *req;
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struct lock_state state = { 0 };
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int write_fd;
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char result = 0;
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int ppid;
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const char *lock_type;
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bool status;
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reset_scheduler();
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if (argc < 4) {
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usage(argv[0]);
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exit(1);
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}
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ppid = atoi(argv[1]);
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write_fd = atoi(argv[2]);
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lock_type = argv[3];
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ev = tevent_context_init(NULL);
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if (ev == NULL) {
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fprintf(stderr, "locking: tevent_context_init() failed\n");
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exit(1);
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}
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se = tevent_add_signal(ev, ev, SIGTERM, 0,
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signal_handler, &state);
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if (se == NULL) {
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fprintf(stderr, "locking: tevent_add_signal() failed\n");
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talloc_free(ev);
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exit(1);
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}
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if (strcmp(lock_type, "RECORD") == 0) {
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if (argc != 7) {
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fprintf(stderr,
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"locking: Invalid number of arguments (%d)\n",
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argc);
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usage(argv[0]);
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exit(1);
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}
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result = lock_record(argv[4], argv[5], argv[6], &state);
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} else if (strcmp(lock_type, "DB") == 0) {
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if (argc != 6) {
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fprintf(stderr,
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"locking: Invalid number of arguments (%d)\n",
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argc);
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usage(argv[0]);
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exit(1);
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}
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result = lock_db(argv[4], argv[5], &state);
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} else {
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fprintf(stderr, "locking: Invalid lock-type '%s'\n", lock_type);
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usage(argv[0]);
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exit(1);
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}
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send_result(write_fd, result);
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req = wait_for_parent_send(ev, ev, ppid);
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if (req == NULL) {
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fprintf(stderr, "locking: wait_for_parent_send() failed\n");
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cleanup(&state);
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exit(1);
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}
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tevent_req_poll(req, ev);
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status = wait_for_parent_recv(req);
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if (! status) {
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fprintf(stderr, "locking: wait_for_parent_recv() failed\n");
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}
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talloc_free(ev);
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cleanup(&state);
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return 0;
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}
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