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 "ctdb_private.h"
  24
  25 static char *progname = NULL;
  26
  27 static void send_result(int fd, char result)
  28 {
  29         sys_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 <log-fd> <ctdbd-pid> <output-fd> RECORD <db-path> <db-flags> <db-key>\n",
  40                 progname);
  41         fprintf(stderr, "       %s <log-fd> <ctdbd-pid> <output-fd> DB <db1-path> <db1-flags> [<db2-path> <db2-flags>...]\n",
  42                 progname);
  43 }
  44
  45 static uint8_t *hex_decode_talloc(TALLOC_CTX *mem_ctx,
  46                                   const char *hex_in, size_t *len)
  47 {
  48         int i, num;
  49         uint8_t *buffer;
  50
  51         *len = strlen(hex_in) / 2;
  52         buffer = talloc_array(mem_ctx, unsigned char, *len);
  53
  54         for (i=0; i<*len; i++) {
  55                 sscanf(&hex_in[i*2], "%02X", &num);
  56                 buffer[i] = (uint8_t)num;
  57         }
  58
  59         return buffer;
  60 }
  61
  62 static int lock_record(const char *dbpath, const char *dbflags, const char *dbkey)
  63 {
  64         TDB_DATA key;
  65         struct tdb_context *tdb;
  66         int tdb_flags;
  67
  68         /* No error checking since CTDB always passes sane values */
  69         tdb_flags = strtol(dbflags, NULL, 0);
  70
  71         /* Convert hex key to key */
  72         if (strcmp(dbkey, "NULL") == 0) {
  73                 key.dptr = NULL;
  74                 key.dsize = 0;
  75         } else {
  76                 key.dptr = hex_decode_talloc(NULL, dbkey, &key.dsize);
  77         }
  78
  79         tdb = tdb_open(dbpath, 0, tdb_flags, O_RDWR, 0600);
  80         if (tdb == NULL) {
  81                 fprintf(stderr, "%s: Error opening database %s\n", progname, dbpath);
  82                 return 1;
  83         }
  84
  85         if (tdb_chainlock(tdb, key) < 0) {
  86                 fprintf(stderr, "%s: Error getting record lock (%s)\n",
  87                         progname, tdb_errorstr(tdb));
  88                 return 1;
  89         }
  90
  91         return 0;
  92
  93 }
  94
  95
  96 static int lock_db(const char *dbpath, const char *dbflags)
  97 {
  98         struct tdb_context *tdb;
  99         int tdb_flags;
 100
 101         /* No error checking since CTDB always passes sane values */
 102         tdb_flags = strtol(dbflags, NULL, 0);
 103
 104         tdb = tdb_open(dbpath, 0, tdb_flags, O_RDWR, 0600);
 105         if (tdb == NULL) {
 106                 fprintf(stderr, "%s: Error opening database %s\n", progname, dbpath);
 107                 return 1;
 108         }
 109
 110         if (tdb_lockall(tdb) < 0) {
 111                 fprintf(stderr, "%s: Error getting db lock (%s)\n",
 112                         progname, tdb_errorstr(tdb));
 113                 return 1;
 114         }
 115
 116         return 0;
 117 }
 118
 119
 120 int main(int argc, char *argv[])
 121 {
 122         int write_fd, log_fd;
 123         char result = 0;
 124         int ppid;
 125         const char *lock_type;
 126
 127         progname = argv[0];
 128
 129         if (argc < 5) {
 130                 usage();
 131                 exit(1);
 132         }
 133
 134         if (!set_scheduler()) {
 135                 fprintf(stderr, "%s: Unable to set real-time scheduler priority\n",
 136                         progname);
 137         }
 138
 139         log_fd = atoi(argv[1]);
 140         close(STDOUT_FILENO);
 141         close(STDERR_FILENO);
 142         dup2(log_fd, STDOUT_FILENO);
 143         dup2(log_fd, STDERR_FILENO);
 144         close(log_fd);
 145
 146         ppid = atoi(argv[2]);
 147         write_fd = atoi(argv[3]);
 148         lock_type = argv[4];
 149
 150         if (strcmp(lock_type, "RECORD") == 0) {
 151                 if (argc != 8) {
 152                         fprintf(stderr, "%s: Invalid number of arguments (%d)\n",
 153                                 progname, argc);
 154                         usage();
 155                         exit(1);
 156                 }
 157                 result = lock_record(argv[5], argv[6], argv[7]);
 158
 159         } else if (strcmp(lock_type, "DB") == 0) {
 160                 int n;
 161
 162                 /* If there are no databases specified, no need for lock */
 163                 if (argc > 5) {
 164                         for (n=5; n+1<argc; n+=2) {
 165                                 result = lock_db(argv[n], argv[n+1]);
 166                                 if (result != 0) {
 167                                         break;
 168                                 }
 169                         }
 170                 }
 171
 172         } else {
 173                 fprintf(stderr, "%s: Invalid lock-type '%s'\n", progname, lock_type);
 174                 usage();
 175                 exit(1);
 176         }
 177
 178         send_result(write_fd, result);
 179
 180         while (kill(ppid, 0) == 0 || errno != ESRCH) {
 181                 sleep(5);
 182         }
 183         return 0;
 184 }