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uucplock.c
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C/C++ Source or Header
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1993-06-07
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5KB
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186 lines
/*
* uucplock.c, uubatch version 1.0.5 :
*
* This code is a modified version of the bsd tip uucplock.c source.
* I got this source from UUNET and modified it a bit, making it
* a complete executable program that locks/unlocks an "object".
*
* Below is the original Copyright found in the original file :
*
*/
/*
* Copyright (c) 1988 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement: ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. Neither the name of the University 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include <sys/types.h>
#include <sys/file.h>
#include <sys/dir.h>
#include <errno.h>
#ifndef NOHDB
#include <stdio.h>
#endif
#ifdef SCO
#include <limits.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#define PMAX _POSIX_PATH_MAX
#define SetPosition SEEK_SET
#define index(_a,_b) strchr(_a,_b)
#else
#define PMAX MAXNAMLEN
#define SetPosition L_SET
#endif
#include "patchlevel.h"
/*
* uucp style locking routines
* return: 0 - success
* -1 - failure
*/
uu_lock(objname)
char *objname;
{
extern int errno;
int fd, pid;
char spid[256];
char tbuf[sizeof(_PATH_LOCKDIRNAME) + PMAX];
off_t lseek();
#ifndef NOHDB
FILE *ffd;
#endif
(void)sprintf(tbuf, _PATH_LOCKDIRNAME, objname);
fd = open(tbuf, O_RDWR|O_CREAT|O_EXCL, 0666);
if (fd < 0) {
/*
* file is already locked
* check to see if the process holding the lock still exists
*/
fd = open(tbuf, O_RDWR, 0);
if (fd < 0) {
perror("lock open");
return(-1);
}
#ifdef NOHDB
/* this is old BSD code, it reads the number in binary */
/* form. This does not go well with HDB... */
if (read(fd, &pid, sizeof(pid)) != sizeof(pid)) {
#else
/* This is code for HDB UUCP, it puts the pid in as text : */
if (!(ffd=fdopen(fd,"r+"))) {
perror("fdopen : lock open");
return(-1);
}
if (!fscanf(ffd,"%d",&pid)) {
#endif
(void)close(fd);
perror("lock read");
return(-1);
}
if (kill(pid, 0) == 0 || errno != ESRCH) {
(void)close(fd); /* process is still running */
return(-1);
}
/*
* The process that locked the file isn't running, so
* we'll lock it ourselves
*/
if (lseek(fd, 0L, SetPosition) < 0) {
(void)close(fd);
perror("lock lseek");
return(-1);
}
/* fall out and finish the locking process */
}
pid = getppid(); /* Parent process is the shell */
#ifdef NOHDB
/* this is old BSD lock code, it writes the number in in binary */
/* form. This does not go well with HDB... */
if (write(fd, (char *)&pid, sizeof(pid)) != sizeof(pid)) {
(void)close(fd);
(void)unlink(tbuf);
perror("lock write");
return(-1);
}
#else
/* This is for HDB UUCP : it puts the pid in as text... */
sprintf(spid,"%10d\n",pid);
if (write(fd, spid, strlen(spid)) != strlen(spid)) {
(void)close(fd);
(void)unlink(tbuf);
perror("lock write");
return(-1);
}
#endif
(void)close(fd);
return(0);
}
uu_unlock(objname)
char *objname;
{
char tbuf[sizeof(_PATH_LOCKDIRNAME) + PMAX];
(void)sprintf(tbuf, _PATH_LOCKDIRNAME, objname);
return(unlink(tbuf));
}
p_usage(s)
char *s;
{
fprintf(stderr," FAILED. Wrong usage.\n");
fprintf(stderr," Usage : %s lock|unlock objname\n");
fprintf(stderr," Will return SUCCES or FAILED string.\n");
exit(-1);
}
main(argc,argv)
int argc;
char **argv;
{
int failed;
if (argc!=3)
p_usage(argv[0]);
if (!strcmp(argv[1],"lock"))
{
fprintf(stderr,"lock : %s\n",
(failed=uu_lock(argv[2])) ? "FAILED" : "SUCCESS" );
exit(failed ? 1 : 0);
}
if (!strcmp(argv[1],"unlock"))
{
fprintf(stderr,"unlock : %s\n",
(failed=uu_unlock(argv[2])) ? "FAILED" : "SUCCESS" );
exit(failed ? 1 : 0);
}
/* If we get here then wrong usage : */
p_usage(argv[0]);
}