Viewing file:  ex_lock.c (5.19 KB) -rw-r--r--
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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997-2004
* Sleepycat Software. All rights reserved.
*
* $Id: ex_lock.c,v 11.21 2004/09/17 22:00:28 mjc Exp $
*/
#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
extern int getopt(int, char * const *, const char *);
#else
#include <unistd.h>
#endif
#include <db.h>
int db_init __P((const char *, u_int32_t, int));
int main __P((int, char *[]));
int usage __P((void));
DB_ENV *dbenv;
const char
*progname = "ex_lock"; /* Program name. */
int
main(argc, argv)
int argc;
char *argv[];
{
extern char *optarg;
extern int optind;
DBT lock_dbt;
DB_LOCK lock;
DB_LOCK *locks;
db_lockmode_t lock_type;
long held;
size_t len;
u_int32_t locker, maxlocks;
int ch, do_unlink, did_get, i, lockid, lockcount, ret;
const char *home;
char opbuf[16], objbuf[1024], lockbuf[16];
home = "TESTDIR";
maxlocks = 0;
do_unlink = 0;
while ((ch = getopt(argc, argv, "h:m:u")) != EOF)
switch (ch) {
case 'h':
home = optarg;
break;
case 'm':
if ((i = atoi(optarg)) <= 0)
return (usage());
maxlocks = (u_int32_t)i; /* XXX: possible overflow. */
break;
case 'u':
do_unlink = 1;
break;
case '?':
default:
return (usage());
}
argc -= optind;
argv += optind;
if (argc != 0)
return (usage());
/* Initialize the database environment. */
if ((ret = db_init(home, maxlocks, do_unlink)) != 0)
return (ret);
locks = 0;
lockcount = 0;
/*
* Accept lock requests.
*/
if ((ret = dbenv->lock_id(dbenv, &locker)) != 0) {
dbenv->err(dbenv, ret, "unable to get locker id");
(void)dbenv->close(dbenv, 0);
return (EXIT_FAILURE);
}
lockid = -1;
memset(&lock_dbt, 0, sizeof(lock_dbt));
for (held = 0, did_get = 0;;) {
printf("Operation get/release [get]> ");
fflush(stdout);
if (fgets(opbuf, sizeof(opbuf), stdin) == NULL)
break;
if ((len = strlen(opbuf)) <= 1 || strcmp(opbuf, "get\n") == 0) {
/* Acquire a lock. */
printf("input object (text string) to lock> ");
fflush(stdout);
if (fgets(objbuf, sizeof(objbuf), stdin) == NULL)
break;
if ((len = strlen(objbuf)) <= 1)
continue;
do {
printf("lock type read/write [read]> ");
fflush(stdout);
if (fgets(lockbuf,
sizeof(lockbuf), stdin) == NULL)
break;
len = strlen(lockbuf);
} while (len > 1 &&
strcmp(lockbuf, "read\n") != 0 &&
strcmp(lockbuf, "write\n") != 0);
if (len == 1 || strcmp(lockbuf, "read\n") == 0)
lock_type = DB_LOCK_READ;
else
lock_type = DB_LOCK_WRITE;
lock_dbt.data = objbuf;
lock_dbt.size = (u_int32_t)strlen(objbuf);
ret = dbenv->lock_get(dbenv, locker,
DB_LOCK_NOWAIT, &lock_dbt, lock_type, &lock);
if (ret == 0) {
did_get = 1;
lockid = lockcount++;
if (locks == NULL)
locks =
(DB_LOCK *)malloc(sizeof(DB_LOCK));
else
locks = (DB_LOCK *)realloc(locks,
lockcount * sizeof(DB_LOCK));
locks[lockid] = lock;
}
} else {
/* Release a lock. */
do {
printf("input lock to release> ");
fflush(stdout);
if (fgets(objbuf,
sizeof(objbuf), stdin) == NULL)
break;
} while ((len = strlen(objbuf)) <= 1);
lockid = strtol(objbuf, NULL, 16);
if (lockid < 0 || lockid >= lockcount) {
printf("Lock #%d out of range\n", lockid);
continue;
}
lock = locks[lockid];
ret = dbenv->lock_put(dbenv, &lock);
did_get = 0;
}
switch (ret) {
case 0:
printf("Lock #%d %s\n", lockid,
did_get ? "granted" : "released");
held += did_get ? 1 : -1;
break;
case DB_LOCK_NOTGRANTED:
dbenv->err(dbenv, ret, NULL);
break;
case DB_LOCK_DEADLOCK:
dbenv->err(dbenv, ret,
"lock_%s", did_get ? "get" : "put");
break;
default:
dbenv->err(dbenv, ret,
"lock_%s", did_get ? "get" : "put");
(void)dbenv->close(dbenv, 0);
return (EXIT_FAILURE);
}
}
printf("\nClosing lock region %ld locks held\n", held);
if (locks != NULL)
free(locks);
if ((ret = dbenv->close(dbenv, 0)) != 0) {
fprintf(stderr,
"%s: dbenv->close: %s\n", progname, db_strerror(ret));
return (EXIT_FAILURE);
}
return (EXIT_SUCCESS);
}
/*
* db_init --
* Initialize the environment.
*/
int
db_init(home, maxlocks, do_unlink)
const char *home;
u_int32_t maxlocks;
int do_unlink;
{
int ret;
if ((ret = db_env_create(&dbenv, 0)) != 0) {
fprintf(stderr, "%s: db_env_create: %s\n",
progname, db_strerror(ret));
return (EXIT_FAILURE);
}
if (do_unlink) {
if ((ret = dbenv->remove(dbenv, home, DB_FORCE)) != 0) {
fprintf(stderr, "%s: dbenv->remove: %s\n",
progname, db_strerror(ret));
return (EXIT_FAILURE);
}
if ((ret = db_env_create(&dbenv, 0)) != 0) {
fprintf(stderr, "%s: db_env_create: %s\n",
progname, db_strerror(ret));
return (EXIT_FAILURE);
}
}
dbenv->set_errfile(dbenv, stderr);
dbenv->set_errpfx(dbenv, progname);
if (maxlocks != 0)
dbenv->set_lk_max_locks(dbenv, maxlocks);
if ((ret =
dbenv->open(dbenv, home, DB_CREATE | DB_INIT_LOCK, 0)) != 0) {
dbenv->err(dbenv, ret, NULL);
(void)dbenv->close(dbenv, 0);
return (EXIT_FAILURE);
}
return (0);
}
int
usage()
{
(void)fprintf(stderr,
"usage: %s [-u] [-h home] [-m maxlocks]\n", progname);
return (EXIT_FAILURE);
}
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