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/* Copyright (c) 1996-2004, Adaptec Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of the Adaptec Corporation nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* UNIX locking mechanism
*/
#include <sys/types.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include "lockunix.h"
static char Lock[] = "/tmp/%s.LOCK";
extern int errno;
static char *
getName(char * name)
{
extern char ** Argv;
if (name) {
return (name);
}
if ((name = strrchr (Argv[0], '/')) != (char *)NULL) {
return (name);
}
return (Argv[0]);
}
#if defined __GNUC__
int
MkLock __P((char * name))
#else
int
MkLock (char * name)
#endif
{
#if defined _DPT_SPARC
extern char * mktemp __P((char * origTemplate));
#endif //_DPT_SPARC
static char Template[] = "/tmp/%s.XXXXXX";
char buffer[10];
int fd;
char * Name = getName (name);
char * templateBuffer = (char *)malloc (strlen(Name)+sizeof(Template)-1);
char * lock;
if (templateBuffer == (char *)NULL) {
return (-1);
}
if ((lock = (char *)malloc (strlen(Name)+sizeof(Lock)-1)) == (char *)NULL) {
free (templateBuffer);
return (-1);
}
sprintf (templateBuffer, Template, Name);
if ((fd = open(mktemp (templateBuffer), O_WRONLY|O_CREAT|O_EXCL, 0644)) < 0) {
free (templateBuffer);
free (lock);
return (-1);
}
sprintf (buffer, "%d\n", (int)getpid());
write (fd, buffer, strlen(buffer));
close (fd);
sprintf (lock, Lock, Name);
if (link (templateBuffer, lock) == 0) {
unlink (templateBuffer);
free (templateBuffer);
free (lock);
return (0);
}
/* Check if the file is valid, and thus has a proper PID */
if ((fd = open(lock, O_RDONLY)) >= 0) {
read (fd, buffer, sizeof(buffer));
close (fd);
if ((fd = atoi (buffer)) == 0) { /* Empty file is a lock */
errno = EPERM;
} else if (kill (fd, 0) == 0) {
unlink (templateBuffer);
free (templateBuffer);
free (lock);
return (fd != getpid()); /* Is it me? */
}
/* Unlink the lock */
if (errno != EPERM) {
unlink (lock);
}
}
fd = link (templateBuffer, lock);
unlink (templateBuffer);
free (templateBuffer);
free (lock);
return (fd);
}
#if defined __GNUC__
void
RmLock __P((char * name))
#else
void
RmLock (char * name)
#endif
{ char * Name = getName (name);
char * lock = (char *)malloc (strlen(Name) + sizeof(Lock) - 1);
if (lock != (char *)NULL) {
sprintf (lock, Lock, Name);
unlink (lock);
free (lock);
}
}
#if defined __GNUC__
void
ChLock __P((char * name, int pid))
#else
void
ChLock (char * name, int pid)
#endif
{ char * Name = getName (name);
int fd;
char buffer[10];
char * lock = (char *)malloc (strlen(Name) + sizeof(Lock) - 1);
if (lock != (char *)NULL) {
sprintf (lock, Lock, Name);
if ((fd = open(lock, O_WRONLY|O_CREAT|O_TRUNC, 0644)) >= 0) {
sprintf (buffer, "%d\n", pid);
write (fd, buffer, strlen(buffer));
close (fd);
}
free (lock);
}
}
#if defined __GNUC__
int
IsLock __P((char * name))
#else
int
IsLock (char * name)
#endif
{ char * Name = getName (name);
int fd;
char buffer[10];
char * lock = (char *)malloc (strlen(Name) + sizeof(Lock) - 1);
if (lock == (char *)NULL) {
return (-1);
}
sprintf (lock, Lock, Name);
fd = open(lock, O_RDONLY);
free (lock);
if (fd < 0) {
return (0);
}
read (fd, buffer, sizeof(buffer));
close (fd);
if ((fd = atoi (buffer)) == 0) { /* Empty file is a lock */
return (-1); /* In transition, try again */
} else if (kill (fd, 0) == 0) {
return (1);
}
return (errno == EPERM); /* Not Locked, permission denied excepted */
}
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