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/*
Copyright (C) Andrew Tridgell 1998
This program 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 of the License, or
(at your option) any later version.
This program 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.
*/
/* support the max connections option */
#include "rsync.h"
int yield_connection(char *fname, int max_connections)
{
int fd, i;
pid_t mypid=getpid(), pid=0;
if (max_connections <= 0)
return 1;
fd = open(fname,O_RDWR);
if (fd == -1) {
rprintf(FERROR,"Couldn't open lock file %s (%s)\n",fname,strerror(errno));
return 0;
}
if (!lock_file(fd)) {
rprintf(FERROR,"failed to lock %s\n", fname);
close(fd);
return 0;
}
/* find the right spot */
for (i=0;i<max_connections;i++) {
if (read(fd, &pid, sizeof(pid)) != sizeof(pid)) {
unlock_file(fd);
close(fd);
return 0;
}
if (pid == mypid) break;
}
if (i == max_connections) {
rprintf(FERROR,"Entry not found in lock file %s\n",fname);
unlock_file(fd);
close(fd);
return 0;
}
pid = 0;
/* remove our mark */
if (lseek(fd,i*sizeof(pid),SEEK_SET) != i*sizeof(pid) ||
write(fd, &pid,sizeof(pid)) != sizeof(pid)) {
rprintf(FERROR,"Couldn't update lock file %s (%s)\n",fname,strerror(errno));
unlock_file(fd);
close(fd);
return 0;
}
unlock_file(fd);
close(fd);
return 1;
}
/****************************************************************************
simple routine to do connection counting
****************************************************************************/
int claim_connection(char *fname,int max_connections)
{
int fd, i;
pid_t pid;
if (max_connections <= 0)
return 1;
fd = open(fname,O_RDWR|O_CREAT, 0600);
if (fd == -1) {
return 0;
}
if (!lock_file(fd)) {
rprintf(FERROR,"failed to lock %s\n", fname);
close(fd);
return 0;
}
/* find a free spot */
for (i=0;i<max_connections;i++) {
if (read(fd,&pid,sizeof(pid)) != sizeof(pid)) break;
if (pid == 0 || !process_exists(pid)) break;
}
if (i == max_connections) {
unlock_file(fd);
close(fd);
return 0;
}
pid = getpid();
if (lseek(fd,i*sizeof(pid),SEEK_SET) != i*sizeof(pid) ||
write(fd, &pid,sizeof(pid)) != sizeof(pid)) {
unlock_file(fd);
close(fd);
return 0;
}
unlock_file(fd);
close(fd);
return 1;
}
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