Mercurial > mbsePi-apps / file comparison
comparison: thermferm/lock.c
thermferm/lock.c
- changeset 51
- a03b6dac5398
- child 106
- 1bd9a16f5061
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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 "thermferm.h" | |
| 24 | |
| 25 /* | |
| 26 * Put a lock on this program. | |
| 27 */ | |
| 28 int lockprog(char *name) | |
| 29 { | |
| 30 char *tempfile, *lockfile; | |
| 31 FILE *fp; | |
| 32 pid_t oldpid; | |
| 33 | |
| 34 tempfile = calloc(PATH_MAX, sizeof(char)); | |
| 35 lockfile = calloc(PATH_MAX, sizeof(char)); | |
| 36 | |
| 37 snprintf(tempfile, PATH_MAX, "/var/run/%s.tmp", name); | |
| 38 snprintf(lockfile, PATH_MAX, "/var/run/%s.pid", name); | |
| 39 | |
| 40 if ((fp = fopen(tempfile, "w")) == NULL) { | |
| 41 perror(name); | |
| 42 printf("Can't create lockfile \"%s\"\n", tempfile); | |
| 43 free(tempfile); | |
| 44 free(lockfile); | |
| 45 return 1; | |
| 46 } | |
| 47 fprintf(fp, "%10u\n", getpid()); | |
| 48 fclose(fp); | |
| 49 | |
| 50 while (TRUE) { | |
| 51 if (link(tempfile, lockfile) == 0) { | |
| 52 unlink(tempfile); | |
| 53 free(tempfile); | |
| 54 free(lockfile); | |
| 55 return 0; | |
| 56 } | |
| 57 if ((fp = fopen(lockfile, "r")) == NULL) { | |
| 58 perror(name); | |
| 59 printf("Can't open lockfile \"%s\"\n", tempfile); | |
| 60 unlink(tempfile); | |
| 61 free(tempfile); | |
| 62 free(lockfile); | |
| 63 return 1; | |
| 64 } | |
| 65 if (fscanf(fp, "%u", &oldpid) != 1) { | |
| 66 perror(name); | |
| 67 printf("Can't read old pid from \"%s\"\n", tempfile); | |
| 68 fclose(fp); | |
| 69 unlink(tempfile); | |
| 70 free(tempfile); | |
| 71 free(lockfile); | |
| 72 return 1; | |
| 73 } | |
| 74 fclose(fp); | |
| 75 if (kill(oldpid,0) == -1) { | |
| 76 if (errno == ESRCH) { | |
| 77 printf("Stale lock found for pid %u\n", oldpid); | |
| 78 unlink(lockfile); | |
| 79 /* no return, try lock again */ | |
| 80 } else { | |
| 81 perror(name); | |
| 82 printf("Kill for %u failed\n",oldpid); | |
| 83 unlink(tempfile); | |
| 84 free(tempfile); | |
| 85 free(lockfile); | |
| 86 return 1; | |
| 87 } | |
| 88 } else { | |
| 89 printf("Another %s is already running, pid=%u\n", name, oldpid); | |
| 90 unlink(tempfile); | |
| 91 free(tempfile); | |
| 92 free(lockfile); | |
| 93 return 1; | |
| 94 } | |
| 95 } | |
| 96 } | |
| 97 | |
| 98 | |
| 99 | |
| 100 void ulockprog(char *name) | |
| 101 { | |
| 102 char *lockfile; | |
| 103 pid_t oldpid; | |
| 104 FILE *fp; | |
| 105 | |
| 106 lockfile = calloc(PATH_MAX, sizeof(char)); | |
| 107 snprintf(lockfile, PATH_MAX, "/var/run/%s.pid", name); | |
| 108 | |
| 109 if ((fp = fopen(lockfile, "r")) == NULL) { | |
| 110 syslog(LOG_NOTICE, "Can't open lockfile \"%s\"", lockfile); | |
| 111 free(lockfile); | |
| 112 return; | |
| 113 } | |
| 114 | |
| 115 if (fscanf(fp, "%u", &oldpid) != 1) { | |
| 116 syslog(LOG_NOTICE, "Can't read old pid from \"%s\"", lockfile); | |
| 117 fclose(fp); | |
| 118 unlink(lockfile); | |
| 119 free(lockfile); | |
| 120 return; | |
| 121 } | |
| 122 | |
| 123 fclose(fp); | |
| 124 | |
| 125 if (oldpid == getpid()) { | |
| 126 (void)unlink(lockfile); | |
| 127 } | |
| 128 | |
| 129 free(lockfile); | |
| 130 } | |
| 131 | |
| 132 |
