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#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <signal.h>
#include <sys/stat.h>
#include "lutil.h"
#ifndef LOCKDIR
#define LOCKDIR "/usr/spool/uucp"
#endif
#define LCKPREFIX LOCKDIR"/LCK.."
#define LCKTMP LOCKDIR"/TMP."
#ifdef DONT_HAVE_PID_T
#define pid_t int
#endif
int lock(line)
char *line;
{
pid_t mypid,rempid=0;
int tmppid;
char tmpname[256],lckname[256];
char *p;
int i,rc;
FILE *f;
rc=-1;
if ((p=strrchr(line,'/')) == NULL) p=line; else p++;
mypid=getpid();
sprintf(tmpname,"%s%d",LCKTMP,mypid);
if ((f=fopen(tmpname,"w")) == NULL)
{
debug(4,"lock cannot create %s",tmpname);
return(-1);
}
#if defined(ASCII_LOCKFILES)
fprintf(f,"%10d\n",mypid);
#elif defined(BINARY_LOCKFILES)
fwrite(&mypid,sizeof(mypid),1,f);
#else
#error Must define ASCII_LOCKFILES or BINARY_LOCKFILES
#endif
fclose(f);
chmod(tmpname,0444);
sprintf(lckname,"%s%s",LCKPREFIX,p);
p=lckname+strlen(lckname)-1;
*p=tolower(*p);
debug(4,"Trying to create %s for %d",lckname,mypid);
for (i=0; (i++<5) && ((rc=link(tmpname,lckname)) != 0) &&
(errno == EEXIST); )
{
if ((f=fopen(lckname,"r")) == NULL)
{
debug(4,"cannot open existing lock file");
}
else
{
#if defined(ASCII_LOCKFILES)
fscanf(f,"%d",&tmppid);
rempid=tmppid;
#elif defined(BINARY_LOCKFILES)
fread(&rempid,sizeof(rempid),1,f);
#endif
fclose(f);
debug(4,"lock file read for process %d",rempid);
}
if (kill(rempid,0) && (errno == ESRCH))
{
debug(4,"process inactive, unlink file");
unlink(lckname);
}
else
{
debug(4,"process active, sleep a bit");
sleep(2);
}
}
unlink(tmpname);
debug(4,"lock result %d (errno %d)",rc,errno);
return(rc);
}
int ulock(line)
char *line;
{
pid_t mypid,rempid;
int tmppid;
char lckname[256];
char *p;
int rc;
FILE *f;
rc=-1;
if ((p=strrchr(line,'/')) == NULL) p=line; else p++;
mypid=getpid();
sprintf(lckname,"%s%s",LCKPREFIX,p);
p=lckname+strlen(lckname)-1;
*p=tolower(*p);
if ((f=fopen(lckname,"r")) == NULL)
{
logerr("$cannot open lock file %s",lckname);
return rc;
}
#if defined(ASCII_LOCKFILES)
fscanf(f,"%d",&tmppid);
rempid=tmppid;
#elif defined(BINARY_LOCKFILES)
fread(&rempid,sizeof(rempid),1,f);
#endif
fclose(f);
if (rempid == mypid)
rc=unlink(lckname);
return(rc);
}
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