vshost-util-vserver

Build script and sources for util-vserver.
git clone https://ccx.te2000.cz/git/vshost-util-vserver
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util-lockfile.c (2147B)

      1 // $Id$    --*- c -*--
      2 
      3 // Copyright (C) 2004 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
      4 //  
      5 // This program is free software; you can redistribute it and/or modify
      6 // it under the terms of the GNU General Public License as published by
      7 // the Free Software Foundation; version 2 of the License.
      8 //  
      9 // This program is distributed in the hope that it will be useful,
     10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
     11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     12 // GNU General Public License for more details.
     13 //  
     14 // You should have received a copy of the GNU General Public License
     15 // along with this program; if not, write to the Free Software
     16 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
     17 
     18 
     19 #ifdef HAVE_CONFIG_H
     20 #  include <config.h>
     21 #endif
     22 
     23 #include "util-lockfile.h"
     24 #include "errinfo.h"
     25 
     26 #include <signal.h>
     27 #include <stdlib.h>
     28 #include <unistd.h>
     29 #include <fcntl.h>
     30 #include <sys/file.h>
     31 #include <errno.h>
     32 
     33 static volatile sig_atomic_t	alarm_flag = 0;
     34 
     35 static void
     36 alarmFunc(int UNUSED sig)
     37 {
     38   alarm_flag = 1;
     39   signal(SIGALRM, alarmFunc);
     40 }
     41 
     42 bool
     43 lockfile(int *fd, char const *filename, int op, long timeout,
     44 	 struct ErrorInformation *err)
     45 {
     46   char const	*errstr = 0;
     47   void		(*old_sighandler)(int) = 0;
     48 
     49   errstr = "open()";
     50   *fd = open(filename, O_CREAT|O_RDONLY|O_NOFOLLOW|O_NONBLOCK, 0644);
     51   if (*fd==-1) goto err;
     52 
     53   if (timeout!=-1) {
     54     errstr = "siginterrupt()";
     55     if (siginterrupt(SIGALRM, 1)==-1) goto err;
     56 
     57     errstr = "signal()";
     58     old_sighandler = signal(SIGALRM, alarmFunc);
     59     if (old_sighandler==SIG_ERR) goto err;
     60 
     61     alarm(timeout);
     62   }
     63 
     64   errstr = "lockf()";
     65   while (lockf(*fd, op, 0)==-1) {
     66     if ((errno!=EINTR && errno!=EINTR) || alarm_flag) goto err;
     67   }
     68 
     69   if (timeout!=-1 && old_sighandler!=0)
     70     signal(SIGALRM, old_sighandler);
     71 
     72   errstr = "fcntl()";
     73   if (fcntl(*fd, F_SETFD, FD_CLOEXEC)==-1) goto err;
     74 
     75   return true;
     76 
     77   err:
     78   if (err) {
     79     err->pos = errstr;
     80     err->id  = errno;
     81   }
     82   if (timeout!=-1 && old_sighandler!=0)
     83     signal(SIGALRM, old_sighandler);
     84   if (*fd!=-1) close(*fd);
     85   return false;
     86 }