diff options
Diffstat (limited to 'camel/camel-lock.c')
-rw-r--r-- | camel/camel-lock.c | 407 |
1 files changed, 0 insertions, 407 deletions
diff --git a/camel/camel-lock.c b/camel/camel-lock.c deleted file mode 100644 index 1bb2ebc35b..0000000000 --- a/camel/camel-lock.c +++ /dev/null @@ -1,407 +0,0 @@ -/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- - * - * Author: Michael Zucchi <notzed@ximian.com> - * - * Copyright (C) 1999 Ximian (www.ximian.com/). - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License as - * published by the Free Software Foundation; either version 2 of the - * License, or (at your option) any later version. - * - * This program 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 General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 - * USA - */ - -#ifdef HAVE_CONFIG_H -#include <config.h> -#endif - -#include <stdio.h> -#include <stdlib.h> -#include <string.h> - -#include <sys/stat.h> -#include <unistd.h> -#include <errno.h> -#ifdef HAVE_ALLOCA_H -#include <alloca.h> -#endif -#include <time.h> - -#ifdef USE_DOT -#include <sys/types.h> -#include <sys/stat.h> -#include <fcntl.h> -#endif - -#ifdef USE_FCNTL -#include <unistd.h> -#include <fcntl.h> -#endif - -#ifdef USE_FLOCK -#include <sys/file.h> -#endif - -#include "camel-lock.h" - -/* dunno where this fucking thing is got from */ -#define _(x) (x) - -#define d(x) /*(printf("%s(%d): ", __FILE__, __LINE__),(x))*/ - -/** - * camel_lock_dot: - * @path: - * @ex: - * - * Create an exclusive lock using .lock semantics. - * All locks are equivalent to write locks (exclusive). - * - * Return value: -1 on error, sets @ex appropriately. - **/ -int -camel_lock_dot(const char *path, CamelException *ex) -{ -#ifdef USE_DOT - char *locktmp, *lock; - int retry = 0; - int fdtmp; - struct stat st; - - /* TODO: Is there a reliable way to refresh the lock, if we're still busy with it? - Does it matter? We will normally also use fcntl too ... */ - - /* use alloca, save cleaning up afterwards */ - lock = alloca(strlen(path) + strlen(".lock") + 1); - sprintf(lock, "%s.lock", path); - locktmp = alloca(strlen(path) + strlen("XXXXXX") + 1); - -#ifndef HAVE_MKSTEMP - sprintf(locktmp, "%sXXXXXX", path); - if (mktemp(locktmp) == NULL) { - /* well, this is really only a programatic error */ - camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM, _("Could not create lock file for %s: %s"), path, strerror(errno)); - return -1; - } -#endif - - while (retry < CAMEL_LOCK_DOT_RETRY) { - - d(printf("trying to lock '%s', attempt %d\n", lock, retry)); - - if (retry > 0) - sleep(CAMEL_LOCK_DOT_DELAY); - -#ifdef HAVE_MKSTEMP - sprintf(locktmp, "%sXXXXXX", path); - fdtmp = mkstemp(locktmp); -#else - fdtmp = open(locktmp, O_RDWR|O_CREAT|O_EXCL, 0600); -#endif - if (fdtmp == -1) { - camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM, _("Could not create lock file for %s: %s"), path, strerror(errno)); - return -1; - } - close(fdtmp); - - /* apparently return code from link can be unreliable for nfs (see link(2)), so we ignore it */ - link(locktmp, lock); - - /* but we check stat instead (again, see link(2)) */ - if (stat(locktmp, &st) == -1) { - d(printf("Out lock file %s vanished!?\n", locktmp)); - - /* well that was unexpected, try cleanup/retry */ - unlink(locktmp); - unlink(lock); - } else { - d(printf("tmp lock created, link count is %d\n", st.st_nlink)); - - unlink(locktmp); - - /* if we had 2 links, we have created the .lock, return ok, otherwise we need to keep trying */ - if (st.st_nlink == 2) - return 0; - } - - /* check for stale lock, kill it */ - if (stat(lock, &st) == 0) { - time_t now = time(0); - (printf("There is an existing lock %ld seconds old\n", now-st.st_ctime)); - if (st.st_ctime < now - CAMEL_LOCK_DOT_STALE) { - d(printf("Removing it now\n")); - unlink(lock); - } - } - - retry++; - } - - d(printf("failed to get lock after %d retries\n", retry)); - - camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM, _("Timed out trying to get lock file on %s. Try again later."), path); - return -1; -#else /* ! USE_DOT */ - return 0; -#endif -} - -/** - * camel_unlock_dot: - * @path: - * - * Attempt to unlock a .lock lock. - **/ -void -camel_unlock_dot(const char *path) -{ -#ifdef USE_DOT - char *lock; - - lock = alloca(strlen(path) + strlen(".lock") + 1); - sprintf(lock, "%s.lock", path); - d(printf("unlocking %s\n", lock)); - (void)unlink(lock); -#endif -} - -/** - * camel_lock_fcntl: - * @fd: - * @type: - * @ex: - * - * Create a lock using fcntl(2). - * - * @type is CAMEL_LOCK_WRITE or CAMEL_LOCK_READ, - * to create exclusive or shared read locks - * - * Return value: -1 on error. - **/ -int -camel_lock_fcntl(int fd, CamelLockType type, CamelException *ex) -{ -#ifdef USE_FCNTL - struct flock lock; - - d(printf("fcntl locking %d\n", fd)); - - memset(&lock, 0, sizeof(lock)); - lock.l_type = type==CAMEL_LOCK_READ?F_RDLCK:F_WRLCK; - if (fcntl(fd, F_SETLK, &lock) == -1) { - camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM, _("Failed to get lock using fcntl(2): %s"), strerror(errno)); - return -1; - } -#endif - return 0; -} - -/** - * camel_unlock_fcntl: - * @fd: - * - * Unlock an fcntl lock. - **/ -void -camel_unlock_fcntl(int fd) -{ -#ifdef USE_FCNTL - struct flock lock; - - d(printf("fcntl unlocking %d\n", fd)); - - memset(&lock, 0, sizeof(lock)); - lock.l_type = F_UNLCK; - fcntl(fd, F_SETLK, &lock); -#endif -} - -/** - * camel_lock_flock: - * @fd: - * @type: - * @ex: - * - * Create a lock using flock(2). - * - * @type is CAMEL_LOCK_WRITE or CAMEL_LOCK_READ, - * to create exclusive or shared read locks - * - * Return value: -1 on error. - **/ -int -camel_lock_flock(int fd, CamelLockType type, CamelException *ex) -{ -#ifdef USE_FLOCK - int op; - - d(printf("flock locking %d\n", fd)); - - if (type == CAMEL_LOCK_READ) - op = LOCK_SH|LOCK_NB; - else - op = LOCK_EX|LOCK_NB; - - if (flock(fd, op) == -1) { - camel_exception_setv(ex, CAMEL_EXCEPTION_SYSTEM, _("Failed to get lock using flock(2): %s"), strerror(errno)); - return -1; - } -#endif - return 0; -} - -/** - * camel_unlock_flock: - * @fd: - * - * Unlock an flock lock. - **/ -void -camel_unlock_flock(int fd) -{ -#ifdef USE_FLOCK - d(printf("flock unlocking %d\n", fd)); - - (void)flock(fd, LOCK_UN); -#endif -} - -/** - * camel_lock_folder: - * @path: Path to the file to lock (used for .locking only). - * @fd: Open file descriptor of the right type to lock. - * @type: Type of lock, CAMEL_LOCK_READ or CAMEL_LOCK_WRITE. - * @ex: - * - * Attempt to lock a folder, multiple attempts will be made using all - * locking strategies available. - * - * Return value: -1 on error, @ex will describe the locking system that failed. - **/ -int -camel_lock_folder(const char *path, int fd, CamelLockType type, CamelException *ex) -{ - int retry = 0; - - while (retry < CAMEL_LOCK_RETRY) { - if (retry > 0) - sleep(CAMEL_LOCK_DELAY); - - camel_exception_clear(ex); - - if (camel_lock_fcntl(fd, type, ex) == 0) { - if (camel_lock_flock(fd, type, ex) == 0) { - if (camel_lock_dot(path, ex) == 0) - return 0; - camel_unlock_flock(fd); - } - camel_unlock_fcntl(fd); - } - retry++; - } - - return -1; -} - -/** - * camel_unlock_folder: - * @path: Filename of folder. - * @fd: Open descrptor on which locks were placed. - * - * Free a lock on a folder. - **/ -void -camel_unlock_folder(const char *path, int fd) -{ - camel_unlock_dot(path); - camel_unlock_flock(fd); - camel_unlock_fcntl(fd); -} - -#if 0 -int main(int argc, char **argv) -{ - CamelException *ex; - int fd1, fd2; - - ex = camel_exception_new(); - -#if 0 - if (camel_lock_dot("mylock", ex) == 0) { - if (camel_lock_dot("mylock", ex) == 0) { - printf("Got lock twice?\n"); - } else { - printf("failed to get lock 2: %s\n", camel_exception_get_description(ex)); - } - camel_unlock_dot("mylock"); - } else { - printf("failed to get lock 1: %s\n", camel_exception_get_description(ex)); - } - - camel_exception_clear(ex); -#endif - - fd1 = open("mylock", O_RDWR); - fd2 = open("mylock", O_RDWR); - - if (camel_lock_fcntl(fd1, CAMEL_LOCK_WRITE, ex) == 0) { - printf("got fcntl write lock once\n"); - sleep(5); - if (camel_lock_fcntl(fd2, CAMEL_LOCK_WRITE, ex) == 0) { - printf("got fcntl write lock twice!\n"); - } else { - printf("failed to get write lock: %s\n", camel_exception_get_description(ex)); - } - - camel_exception_clear(ex); - - if (camel_lock_fcntl(fd2, CAMEL_LOCK_READ, ex) == 0) { - printf("got fcntl read lock as well?\n"); - camel_unlock_fcntl(fd2); - } else { - printf("failed to get read lock: %s\n", camel_exception_get_description(ex)); - } - - camel_exception_clear(ex); - camel_unlock_fcntl(fd1); - } else { - printf("failed to get write lock at all: %s\n", camel_exception_get_description(ex)); - } - - if (camel_lock_fcntl(fd1, CAMEL_LOCK_READ, ex) == 0) { - printf("got fcntl read lock once\n"); - sleep(5); - if (camel_lock_fcntl(fd2, CAMEL_LOCK_WRITE, ex) == 0) { - printf("got fcntl write lock too?!\n"); - } else { - printf("failed to get write lock: %s\n", camel_exception_get_description(ex)); - } - - camel_exception_clear(ex); - - if (camel_lock_fcntl(fd2, CAMEL_LOCK_READ, ex) == 0) { - printf("got fcntl read lock twice\n"); - camel_unlock_fcntl(fd2); - } else { - printf("failed to get read lock: %s\n", camel_exception_get_description(ex)); - } - - camel_exception_clear(ex); - camel_unlock_fcntl(fd1); - } - - close(fd1); - close(fd2); - - return 0; -} -#endif |