ctdb/server/ctdb_lock_helper.c

   1 /*
   2    ctdb lock helper
   3
   4    Copyright (C) Amitay Isaacs  2013
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "tdb.h"
  22 #include "system/filesys.h"
  23 #include "../include/ctdb_private.h"
  24
  25 static char *progname = NULL;
  26
  27 static void send_result(int fd, char result)
  28 {
  29         write(fd, &result, 1);
  30         if (result == 1) {
  31                 exit(1);
  32         }
  33 }
  34
  35
  36 static void usage(void)
  37 {
  38         fprintf(stderr, "\n");
  39         fprintf(stderr, "Usage: %s <ctdbd-pid> <output-fd> RECORD <db-path> <db-key>\n",
  40                 progname);
  41         fprintf(stderr, "       %s <ctdbd-pid> <output-fd> DB <db1-path> [<db2-path> ...]\n",
  42                 progname);
  43 }
  44
  45
  46 static int lock_record(const char *dbpath, const char *dbkey)
  47 {
  48         TDB_DATA key;
  49         struct tdb_context *tdb;
  50
  51         /* Convert hex key to key */
  52         if (strcmp(dbkey, "NULL") == 0) {
  53                 key.dptr = NULL;
  54                 key.dsize = 0;
  55         } else {
  56                 key.dptr = hex_decode_talloc(NULL, dbkey, &key.dsize);
  57         }
  58
  59         tdb = tdb_open(dbpath, 0, TDB_DEFAULT, O_RDWR, 0600);
  60         if (tdb == NULL) {
  61                 fprintf(stderr, "%s: Error opening database %s\n", progname, dbpath);
  62                 return 1;
  63         }
  64
  65         if (tdb_chainlock(tdb, key) < 0) {
  66                 fprintf(stderr, "%s: Error getting record lock (%s)\n",
  67                         progname, tdb_errorstr(tdb));
  68                 return 1;
  69         }
  70
  71         return 0;
  72
  73 }
  74
  75
  76 static int lock_db(const char *dbpath)
  77 {
  78         struct tdb_context *tdb;
  79
  80         tdb = tdb_open(dbpath, 0, TDB_DEFAULT, O_RDWR, 0600);
  81         if (tdb == NULL) {
  82                 fprintf(stderr, "%s: Error opening database %s\n", progname, dbpath);
  83                 return 1;
  84         }
  85
  86         if (tdb_lockall(tdb) < 0) {
  87                 fprintf(stderr, "%s: Error getting db lock (%s)\n",
  88                         progname, tdb_errorstr(tdb));
  89                 return 1;
  90         }
  91
  92         return 0;
  93 }
  94
  95
  96 int main(int argc, char *argv[])
  97 {
  98         int write_fd;
  99         char result = 0;
 100         int ppid;
 101         const char *lock_type;
 102
 103         progname = argv[0];
 104
 105         if (argc < 4) {
 106                 usage();
 107                 exit(1);
 108         }
 109
 110         ppid = atoi(argv[1]);
 111         write_fd = atoi(argv[2]);
 112         lock_type = argv[3];
 113
 114         if (strcmp(lock_type, "RECORD") == 0) {
 115                 if (argc != 6) {
 116                         fprintf(stderr, "%s: Invalid number of arguments (%d)\n",
 117                                 progname, argc);
 118                         usage();
 119                         exit(1);
 120                 }
 121                 result = lock_record(argv[4], argv[5]);
 122
 123         } else if (strcmp(lock_type, "DB") == 0) {
 124                 int n;
 125
 126                 /* If there are no databases specified, no need for lock */
 127                 if (argc > 4) {
 128                         for (n=4; n<argc; n++) {
 129                                 result = lock_db(argv[n]);
 130                                 if (result != 0) {
 131                                         break;
 132                                 }
 133                         }
 134                 }
 135
 136         } else {
 137                 fprintf(stderr, "%s: Invalid lock-type '%s'\n", progname, lock_type);
 138                 usage();
 139                 exit(1);
 140         }
 141
 142         send_result(write_fd, result);
 143
 144         while (kill(ppid, 0) == 0 || errno != ESRCH) {
 145                 sleep(5);
 146         }
 147         return 0;
 148 }