Mercurial > mbsePi-apps / file comparison
comparison: lib/lock.c
lib/lock.c
- changeset 51
- a03b6dac5398
- parent 50
- 8b5e8f1e172d
- child 52
- 4387a6b11eb3
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| 50:8b5e8f1e172d | 51:a03b6dac5398 |
|---|---|
| 1 /***************************************************************************** | |
| 2 * Copyright (C) 2014 | |
| 3 * | |
| 4 * Michiel Broek <mbroek at mbse dot eu> | |
| 5 * | |
| 6 * This file is part of the mbsePi-apps | |
| 7 * | |
| 8 * This is free software; you can redistribute it and/or modify it | |
| 9 * under the terms of the GNU General Public License as published by the | |
| 10 * Free Software Foundation; either version 2, or (at your option) any | |
| 11 * later version. | |
| 12 * | |
| 13 * mbsePi-apps is distributed in the hope that it will be useful, but | |
| 14 * WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 16 * General Public License for more details. | |
| 17 * | |
| 18 * You should have received a copy of the GNU General Public License | |
| 19 * along with EC-65K; see the file COPYING. If not, write to the Free | |
| 20 * Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. | |
| 21 *****************************************************************************/ | |
| 22 | |
| 23 #include "../config.h" | |
| 24 #include "mbselib.h" | |
| 25 | |
| 26 /* | |
| 27 * Put a lock on this program. | |
| 28 */ | |
| 29 int lockprog(char *name) | |
| 30 { | |
| 31 char *tempfile, *lockfile; | |
| 32 FILE *fp; | |
| 33 pid_t oldpid; | |
| 34 | |
| 35 tempfile = calloc(PATH_MAX, sizeof(char)); | |
| 36 lockfile = calloc(PATH_MAX, sizeof(char)); | |
| 37 | |
| 38 snprintf(tempfile, PATH_MAX, "/var/run/%s.tmp", name); | |
| 39 snprintf(lockfile, PATH_MAX, "/var/run/%s.pid", name); | |
| 40 | |
| 41 if ((fp = fopen(tempfile, "w")) == NULL) { | |
| 42 perror(name); | |
| 43 printf("Can't create lockfile \"%s\"\n", tempfile); | |
| 44 free(tempfile); | |
| 45 free(lockfile); | |
| 46 return 1; | |
| 47 } | |
| 48 fprintf(fp, "%10u\n", getpid()); | |
| 49 fclose(fp); | |
| 50 | |
| 51 while (TRUE) { | |
| 52 if (link(tempfile, lockfile) == 0) { | |
| 53 unlink(tempfile); | |
| 54 free(tempfile); | |
| 55 free(lockfile); | |
| 56 return 0; | |
| 57 } | |
| 58 if ((fp = fopen(lockfile, "r")) == NULL) { | |
| 59 perror(name); | |
| 60 printf("Can't open lockfile \"%s\"\n", tempfile); | |
| 61 unlink(tempfile); | |
| 62 free(tempfile); | |
| 63 free(lockfile); | |
| 64 return 1; | |
| 65 } | |
| 66 if (fscanf(fp, "%u", &oldpid) != 1) { | |
| 67 perror(name); | |
| 68 printf("Can't read old pid from \"%s\"\n", tempfile); | |
| 69 fclose(fp); | |
| 70 unlink(tempfile); | |
| 71 free(tempfile); | |
| 72 free(lockfile); | |
| 73 return 1; | |
| 74 } | |
| 75 fclose(fp); | |
| 76 if (kill(oldpid,0) == -1) { | |
| 77 if (errno == ESRCH) { | |
| 78 printf("Stale lock found for pid %u\n", oldpid); | |
| 79 unlink(lockfile); | |
| 80 /* no return, try lock again */ | |
| 81 } else { | |
| 82 perror(name); | |
| 83 printf("Kill for %u failed\n",oldpid); | |
| 84 unlink(tempfile); | |
| 85 free(tempfile); | |
| 86 free(lockfile); | |
| 87 return 1; | |
| 88 } | |
| 89 } else { | |
| 90 printf("Another %s is already running, pid=%u\n", name, oldpid); | |
| 91 unlink(tempfile); | |
| 92 free(tempfile); | |
| 93 free(lockfile); | |
| 94 return 1; | |
| 95 } | |
| 96 } | |
| 97 } | |
| 98 | |
| 99 | |
| 100 | |
| 101 void ulockprog(char *name) | |
| 102 { | |
| 103 char *lockfile; | |
| 104 pid_t oldpid; | |
| 105 FILE *fp; | |
| 106 | |
| 107 lockfile = calloc(PATH_MAX, sizeof(char)); | |
| 108 snprintf(lockfile, PATH_MAX, "/var/run/%s.pid", name); | |
| 109 | |
| 110 if ((fp = fopen(lockfile, "r")) == NULL) { | |
| 111 syslog(LOG_NOTICE, "Can't open lockfile \"%s\"", lockfile); | |
| 112 free(lockfile); | |
| 113 return; | |
| 114 } | |
| 115 | |
| 116 if (fscanf(fp, "%u", &oldpid) != 1) { | |
| 117 syslog(LOG_NOTICE, "Can't read old pid from \"%s\"", lockfile); | |
| 118 fclose(fp); | |
| 119 unlink(lockfile); | |
| 120 free(lockfile); | |
| 121 return; | |
| 122 } | |
| 123 | |
| 124 fclose(fp); | |
| 125 | |
| 126 if (oldpid == getpid()) { | |
| 127 (void)unlink(lockfile); | |
| 128 } | |
| 129 | |
| 130 free(lockfile); | |
| 131 } | |
| 132 | |
| 133 |
