andre@1160: /* Copyright (C) 2014 by Bundesamt für Sicherheit in der Informationstechnik
andre@1160:  * Software engineering by Intevation GmbH
andre@1160:  *
andre@1160:  * This file is Free Software under the GNU GPL (v>=2)
andre@1160:  * and comes with ABSOLUTELY NO WARRANTY!
andre@1160:  * See LICENSE.txt for details.
andre@1160:  */
andre@1160: 
wilde@782: #ifndef WIN32
wilde@782: 
wilde@782: #include <fcntl.h>
wilde@782: #include <stdio.h>
wilde@782: #include <sys/types.h>
wilde@782: #include <unistd.h>
andre@1332: #include <string.h>
wilde@782: 
wilde@782: #include "logging.h"
andre@1332: #include "util.h"
andre@1332: #include "strhelp.h"
wilde@782: 
wilde@782: int
wilde@782: open_lockfile(char *path)
wilde@782: {
wilde@782:   int fd;
wilde@782:   char pidstr[20];
wilde@782:   size_t pidstrlen;
wilde@782:   struct flock lk;
wilde@782:   fd = open(path, O_RDWR | O_CREAT, 0600);
wilde@782:   if (fd != -1)
wilde@782:     {
wilde@782:       /* Get an exclusive lock on the whole file. */
wilde@782:       lk.l_type = F_WRLCK;
wilde@782:       lk.l_whence = SEEK_SET;
wilde@782:       lk.l_start = 0;
wilde@782:       lk.l_len = 0;
andre@1332:       fcntl(fd, F_SETLK, &lk);
wilde@782:       if (fcntl(fd, F_SETLK, &lk) != -1)
andre@1332:          {
andre@1332:            char oldpid[20];
andre@1332:            FILE *f = fopen(path, "r");
andre@1332:            size_t bytes_read;
andre@1332:            if (f)
andre@1332:              {
andre@1332:                bytes_read = fread(oldpid, 1, sizeof(oldpid), f);
andre@1333:                fclose(f);
andre@1332:                if (bytes_read)
andre@1332:                  {
andre@1332:                    char *oldPath,
andre@1332:                         *newPath;
andre@1332:                    if (bytes_read == sizeof(oldpid))
andre@1332:                      {
andre@1332:                        ERRORPRINTF ("Bad information in pidfile\n");
andre@1332:                      }
andre@1332:                    else
andre@1332:                      {
andre@1332:                        oldpid[bytes_read] = '\0';
andre@1332:                        oldPath = get_proc_install_dir(oldpid);
andre@1332:                        newPath = get_install_dir();
andre@1332:                        if (oldPath && newPath && strcmp(oldPath, newPath) == 0)
andre@1332:                          {
andre@1332:                            DEBUGPRINTF("Got lock but process from %s is still"
andre@1332:                                        "running.\n", oldPath);
andre@1332:                            xfree(oldPath);
andre@1332:                            xfree(newPath);
andre@1332:                            return -1;
andre@1332:                          }
andre@1332:                        xfree(oldPath);
andre@1332:                        xfree(newPath);
andre@1332:                      }
andre@1332:                  }
andre@1332:              }
andre@1332: 
andre@1332:            ftruncate(fd, 0);
andre@1332:            pidstrlen = (size_t)snprintf(pidstr, sizeof(pidstr), "%d",
andre@1332:                                         getpid());
andre@1332:            write(fd, pidstr, pidstrlen);
andre@1332:          }
andre@1332:        else
andre@1332:          {
andre@1332:            /* Lock can not be acquired.  Bail out... */
andre@1332:            close(fd);
andre@1332:            DEBUGPRINTF("Could not get an exclusive lock on %s.\n", path);
andre@1332:            return -1;
andre@1332:          }
wilde@782:     }
wilde@782:   else
wilde@782:     {
wilde@782:       DEBUGPRINTF("Failed to open lock file: %s.\n", path);
wilde@782:     }
wilde@782:   return fd;
wilde@782: }
wilde@782: 
wilde@782: void
wilde@782: close_lockfile(int fd)
wilde@782: {
wilde@782:   struct flock lk;
wilde@782: 
wilde@782:   /* Delete the PID from file. */
wilde@782:   /* We do this instead of trying to unlink the file. */
wilde@782:   ftruncate(fd, 0);
wilde@782: 
wilde@782:   /* Remove lock from the file. */
wilde@782:   lk.l_type = F_UNLCK;
wilde@782:   lk.l_whence = SEEK_SET;
wilde@782:   lk.l_start = 0;
wilde@782:   lk.l_len = 0;
wilde@782:   if (fcntl(fd, F_SETLK, &lk) == -1)
wilde@782:     {
andre@1250:       /* Lock can not be removed */
andre@1250:       DEBUGPRINTF("Could not remove lock from pid file.\n");
wilde@782:     }
wilde@782:   close(fd);
wilde@782: }
wilde@782: 
wilde@782: #endif /* Not WIN32 */