mirror of
https://github.com/netfun2000/lcd4linux.git
synced 2026-02-27 09:44:34 +08:00
6d5d1055ea
git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@840 3ae390bd-cb1e-0410-b409-cd5a39f66f1f
151 lines
3.4 KiB
C
151 lines
3.4 KiB
C
/* $Id$
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* $URL$
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*
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* PID file handling
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*
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* Copyright (C) 1999, 2000 Michael Reinelt <michael@reinelt.co.at>
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*
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* This file is part of LCD4Linux.
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*
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* LCD4Linux 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 2, or (at your option)
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* any later version.
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*
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* LCD4Linux 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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*
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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, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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/*
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* exported functions:
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*
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* int pid_init (const char *pidfile)
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* returns 0 if PID file could be successfully created
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* returns PID of an already running process
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* returns -1 in case of an error
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* int pid_exit (const char *pidfile)
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* returns 0 if PID file could be successfully deleted
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* otherwise returns error from unlink() call
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*
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*/
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#include "config.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include "debug.h"
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#include "pid.h"
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#include "qprintf.h"
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#ifdef WITH_DMALLOC
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#include <dmalloc.h>
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#endif
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int pid_init(const char *pidfile)
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{
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char tmpfile[256];
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char buffer[16];
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int fd, len, pid;
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qprintf(tmpfile, sizeof(tmpfile), "%s.%s", pidfile, "XXXXXX");
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if ((fd = mkstemp(tmpfile)) == -1) {
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error("mkstemp(%s) failed: %s", tmpfile, strerror(errno));
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return -1;
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}
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if (fchmod(fd, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) == -1) {
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error("fchmod(%s) failed: %s", tmpfile, strerror(errno));
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close(fd);
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unlink(tmpfile);
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return -1;
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}
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qprintf(buffer, sizeof(buffer), "%d\n", (int) getpid());
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len = strlen(buffer);
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if (write(fd, buffer, len) != len) {
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error("write(%s) failed: %s", tmpfile, strerror(errno));
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close(fd);
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unlink(tmpfile);
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return -1;
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}
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close(fd);
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while (link(tmpfile, pidfile) == -1) {
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if (errno != EEXIST) {
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error("link(%s, %s) failed: %s", tmpfile, pidfile, strerror(errno));
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unlink(tmpfile);
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return -1;
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}
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if ((fd = open(pidfile, O_RDONLY)) == -1) {
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if (errno == ENOENT)
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continue; /* pidfile disappared */
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error("open(%s) failed: %s", pidfile, strerror(errno));
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unlink(tmpfile);
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return -1;
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}
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len = read(fd, buffer, sizeof(buffer) - 1);
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if (len < 0) {
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error("read(%s) failed: %s", pidfile, strerror(errno));
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unlink(tmpfile);
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return -1;
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}
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buffer[len] = '\0';
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if (sscanf(buffer, "%d", &pid) != 1 || pid == 0) {
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error("scan(%s) failed.", pidfile);
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unlink(tmpfile);
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return -1;
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}
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if (pid == getpid()) {
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error("%s already locked by us. uh-oh...", pidfile);
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unlink(tmpfile);
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return 0;
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}
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if ((kill(pid, 0) == -1) && errno == ESRCH) {
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error("removing stale PID file %s", pidfile);
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if (unlink(pidfile) == -1 && errno != ENOENT) {
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error("unlink(%s) failed: %s", pidfile, strerror(errno));
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unlink(tmpfile);
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return pid;
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}
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continue;
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}
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unlink(tmpfile);
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return pid;
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}
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unlink(tmpfile);
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return 0;
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}
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int pid_exit(const char *pidfile)
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{
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return unlink(pidfile);
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}
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