1 | /* pidfile.c
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2 | *
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3 | * Functions to assist in the writing and removing of pidfiles.
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4 | *
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5 | * Russ Dill <Russ.Dill@asu.edu> September 2001
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6 | *
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7 | * This program is free software; you can redistribute it and/or modify
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8 | * it under the terms of the GNU General Public License as published by
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9 | * the Free Software Foundation; either version 2 of the License, or
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10 | * (at your option) any later version.
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11 | *
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12 | * This program is distributed in the hope that it will be useful,
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 | * GNU General Public License for more details.
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16 | *
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17 | * You should have received a copy of the GNU General Public License
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18 | * along with this program; if not, write to the Free Software
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19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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20 | */
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21 |
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22 | #include <sys/types.h>
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23 | #include <sys/stat.h>
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24 | #include <fcntl.h>
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25 | #include <unistd.h>
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26 | #include <stdio.h>
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27 | #include <stdlib.h>
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28 |
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29 | #include "common.h"
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30 | #include "pidfile.h"
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31 |
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32 | static char *saved_pidfile;
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33 |
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34 | static void pidfile_delete(void)
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35 | {
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36 | if (saved_pidfile) unlink(saved_pidfile);
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37 | }
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38 |
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39 |
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40 | int pidfile_acquire(const char *pidfile)
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41 | {
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42 | int pid_fd;
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43 | if (!pidfile) return -1;
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44 |
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45 | pid_fd = open(pidfile, O_CREAT | O_WRONLY, 0644);
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46 | if (pid_fd < 0) {
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47 | LOG(LOG_ERR, "Unable to open pidfile %s: %m\n", pidfile);
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48 | } else {
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49 | lockf(pid_fd, F_LOCK, 0);
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50 | if (!saved_pidfile)
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51 | atexit(pidfile_delete);
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52 | saved_pidfile = (char *) pidfile;
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53 | }
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54 |
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55 | return pid_fd;
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56 | }
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57 |
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58 |
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59 | void pidfile_write_release(int pid_fd)
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60 | {
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61 | FILE *out;
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62 |
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63 | if (pid_fd < 0) return;
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64 |
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65 | if ((out = fdopen(pid_fd, "w")) != NULL) {
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66 | fprintf(out, "%d\n", getpid());
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67 | fclose(out);
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68 | }
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69 | lockf(pid_fd, F_UNLCK, 0);
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70 | close(pid_fd);
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71 | }
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72 |
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73 |
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74 |
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75 |
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