[821] | 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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