diff options
Diffstat (limited to '')
| -rw-r--r-- | lock.c | 211 |
1 files changed, 0 insertions, 211 deletions
@@ -1,211 +0,0 @@ -/* $Id: lock.c,v 1.7 2004/03/03 03:47:04 reinelt Exp $ - * - * UUCP style locking - * - * Copyright 1999, 2000 Michael Reinelt <reinelt@eunet.at> - * - * This file is part of LCD4Linux. - * - * LCD4Linux 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, or (at your option) - * any later version. - * - * LCD4Linux 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., 675 Mass Ave, Cambridge, MA 02139, USA. - * - * - * $Log: lock.c,v $ - * Revision 1.7 2004/03/03 03:47:04 reinelt - * big patch from Martin Hejl: - * - use qprintf() where appropriate - * - save CPU cycles on gettimeofday() - * - add quit() functions to free allocated memory - * - fixed lots of memory leaks - * - * Revision 1.6 2004/01/29 04:40:02 reinelt - * every .c file includes "config.h" now - * - * Revision 1.5 2003/10/05 17:58:50 reinelt - * libtool junk; copyright messages cleaned up - * - * Revision 1.4 2003/09/19 08:40:32 reinelt - * - * - * increased version number to 0.9.12 - * port locking is done as /var/lock/LCK..usb_tts_0 for /dev/usb/tts/0 - * - * Revision 1.3 2001/04/27 05:04:57 reinelt - * - * replaced OPEN_MAX with sysconf() - * replaced mktemp() with mkstemp() - * unlock serial port if open() fails - * - * Revision 1.2 2000/08/10 09:44:09 reinelt - * - * new debugging scheme: error(), info(), debug() - * uses syslog if in daemon mode - * - * Revision 1.1 2000/04/07 05:42:20 reinelt - * - * UUCP style lockfiles for the serial port - * - */ - -/* - * exported functions: - * - * pid_t lock_port (char *port) - * returns 0 if port could be successfully locked - * otherwise returns PID of the process holding the lock - * - * pid_t unlock_port (char *port) - * returns 0 if port could be successfully unlocked - * otherwise returns PID of the process holding the lock - * - */ - - -#include "config.h" - -#include <stdlib.h> -#include <stdio.h> -#include <string.h> -#include <unistd.h> -#include <fcntl.h> -#include <errno.h> -#include <signal.h> -#include <sys/types.h> -#include <sys/stat.h> - - -#include "debug.h" -#include "lock.h" -#include "qprintf.h" - - -pid_t lock_port (char *Port) -{ - char lockfile[256]; - char tempfile[256]; - char buffer[16]; - char *port, *p; - int fd, len, pid; - - if (strncmp(Port, "/dev/", 5)==0) { - port=strdup(Port+5); - } else { - port=strdup(Port); - } - - while ((p=strchr(port, '/'))!=NULL) { - *p='_'; - } - - qprintf(lockfile, sizeof(lockfile), LOCK, port); - qprintf(tempfile, sizeof(tempfile), LOCK, "TMP.XXXXXX"); - - free (port); - - if ((fd=mkstemp(tempfile))==-1) { - error ("mkstemp(%s) failed: %s", tempfile, strerror(errno)); - return -1; - } - - if (fchmod(fd,S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)==-1) { - error ("fchmod(%s) failed: %s", tempfile, strerror(errno)); - close(fd); - unlink(tempfile); - return -1; - } - - snprintf (buffer, sizeof(buffer), "%10d\n", (int)getpid()); - if (write(fd, buffer, strlen(buffer))!=strlen(buffer)) { - error ("write(%s) failed: %s", tempfile, strerror(errno)); - close(fd); - unlink(tempfile); - return -1; - } - close (fd); - - - while (link(tempfile, lockfile)==-1) { - - if (errno!=EEXIST) { - error ("link(%s, %s) failed: %s", tempfile, lockfile, strerror(errno)); - unlink(tempfile); - return -1; - } - - if ((fd=open(lockfile, O_RDONLY))==-1) { - if (errno==ENOENT) continue; // lockfile disappared - error ("open(%s) failed: %s", lockfile, strerror(errno)); - unlink (tempfile); - return -1; - } - - len=read(fd, buffer, sizeof(buffer)-1); - if (len<0) { - error ("read(%s) failed: %s", lockfile, strerror(errno)); - unlink (tempfile); - return -1; - } - - buffer[len]='\0'; - if (sscanf(buffer, "%d", &pid)!=1 || pid==0) { - error ("scan(%s) failed.", lockfile); - unlink (tempfile); - return -1; - } - - if (pid==getpid()) { - error ("%s already locked by us. uh-oh...", lockfile); - unlink(tempfile); - return 0; - } - - if ((kill(pid, 0)==-1) && errno==ESRCH) { - error ("removing stale lockfile %s", lockfile); - if (unlink(lockfile)==-1 && errno!=ENOENT) { - error ("unlink(%s) failed: %s", lockfile, strerror(errno)); - unlink(tempfile); - return pid; - } - continue; - } - unlink (tempfile); - return pid; - } - - unlink (tempfile); - return 0; -} - - -pid_t unlock_port (char *Port) -{ - char lockfile[256]; - char *port, *p; - - if (strncmp(Port, "/dev/", 5)==0) { - port=strdup(Port+5); - } else { - port=strdup(Port); - } - - while ((p=strchr(port, '/'))!=NULL) { - *p='_'; - } - - qprintf(lockfile, sizeof(lockfile), LOCK, port); - unlink (lockfile); - free (port); - - return 0; -} |