Mercurial > mbsePi-apps / file comparison
comparison: brewco/lock.c
brewco/lock.c
- changeset 487
- d5bc44183aa4
- parent 486
- 5a237a99a793
- child 488
- bee1f70fb42b
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| 486:5a237a99a793 | 487:d5bc44183aa4 |
|---|---|
| 1 /***************************************************************************** | |
| 2 * Copyright (C) 2015 | |
| 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 ThermFerm; 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 "lock.h" | |
| 24 #include "brewco.h" | |
| 25 | |
| 26 extern char *varpath; | |
| 27 | |
| 28 | |
| 29 /* | |
| 30 * Put a lock on this program. | |
| 31 */ | |
| 32 int lockprog(char *name) | |
| 33 { | |
| 34 char *tempfile, *lockfile; | |
| 35 FILE *fp; | |
| 36 pid_t oldpid; | |
| 37 | |
| 38 tempfile = calloc(PATH_MAX, sizeof(char)); | |
| 39 lockfile = calloc(PATH_MAX, sizeof(char)); | |
| 40 | |
| 41 snprintf(tempfile, PATH_MAX, "%s%s.tmp", varpath, name); | |
| 42 snprintf(lockfile, PATH_MAX, "%s%s.pid", varpath, name); | |
| 43 | |
| 44 if ((fp = fopen(tempfile, "w")) == NULL) { | |
| 45 perror(name); | |
| 46 printf("Can't create lockfile \"%s\"\n", tempfile); | |
| 47 free(tempfile); | |
| 48 free(lockfile); | |
| 49 return 1; | |
| 50 } | |
| 51 fprintf(fp, "%10u\n", getpid()); | |
| 52 fclose(fp); | |
| 53 | |
| 54 while (TRUE) { | |
| 55 if (link(tempfile, lockfile) == 0) { | |
| 56 unlink(tempfile); | |
| 57 free(tempfile); | |
| 58 free(lockfile); | |
| 59 return 0; | |
| 60 } | |
| 61 if ((fp = fopen(lockfile, "r")) == NULL) { | |
| 62 perror(name); | |
| 63 printf("Can't open lockfile \"%s\"\n", tempfile); | |
| 64 unlink(tempfile); | |
| 65 free(tempfile); | |
| 66 free(lockfile); | |
| 67 return 1; | |
| 68 } | |
| 69 if (fscanf(fp, "%u", &oldpid) != 1) { | |
| 70 perror(name); | |
| 71 printf("Can't read old pid from \"%s\"\n", tempfile); | |
| 72 fclose(fp); | |
| 73 unlink(tempfile); | |
| 74 free(tempfile); | |
| 75 free(lockfile); | |
| 76 return 1; | |
| 77 } | |
| 78 fclose(fp); | |
| 79 if (kill(oldpid,0) == -1) { | |
| 80 if (errno == ESRCH) { | |
| 81 printf("Stale lock found for pid %u\n", oldpid); | |
| 82 unlink(lockfile); | |
| 83 /* no return, try lock again */ | |
| 84 } else { | |
| 85 perror(name); | |
| 86 printf("Kill for %u failed\n",oldpid); | |
| 87 unlink(tempfile); | |
| 88 free(tempfile); | |
| 89 free(lockfile); | |
| 90 return 1; | |
| 91 } | |
| 92 } else { | |
| 93 printf("Another %s is already running, pid=%u\n", name, oldpid); | |
| 94 unlink(tempfile); | |
| 95 free(tempfile); | |
| 96 free(lockfile); | |
| 97 return 1; | |
| 98 } | |
| 99 } | |
| 100 } | |
| 101 | |
| 102 | |
| 103 | |
| 104 void ulockprog(char *name) | |
| 105 { | |
| 106 char *lockfile; | |
| 107 pid_t oldpid; | |
| 108 FILE *fp; | |
| 109 | |
| 110 lockfile = calloc(PATH_MAX, sizeof(char)); | |
| 111 snprintf(lockfile, PATH_MAX, "%s%s.pid", varpath, name); | |
| 112 | |
| 113 if ((fp = fopen(lockfile, "r")) == NULL) { | |
| 114 syslog(LOG_NOTICE, "Can't open lockfile \"%s\"", lockfile); | |
| 115 free(lockfile); | |
| 116 return; | |
| 117 } | |
| 118 | |
| 119 if (fscanf(fp, "%u", &oldpid) != 1) { | |
| 120 syslog(LOG_NOTICE, "Can't read old pid from \"%s\"", lockfile); | |
| 121 fclose(fp); | |
| 122 unlink(lockfile); | |
| 123 free(lockfile); | |
| 124 return; | |
| 125 } | |
| 126 | |
| 127 fclose(fp); | |
| 128 | |
| 129 if (oldpid == getpid()) { | |
| 130 (void)unlink(lockfile); | |
| 131 } | |
| 132 | |
| 133 free(lockfile); | |
| 134 } | |
| 135 | |
| 136 |
