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 <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 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 *dbkey)
  63 {
  64         TDB_DATA key;
  65         struct tdb_context *tdb;
  66
  67         /* Convert hex key to key */
  68         if (strcmp(dbkey, "NULL") == 0) {
  69                 key.dptr = NULL;
  70                 key.dsize = 0;
  71         } else {
  72                 key.dptr = hex_decode_talloc(NULL, dbkey, &key.dsize);
  73         }
  74
  75         tdb = tdb_open(dbpath, 0, TDB_DEFAULT, O_RDWR, 0600);
  76         if (tdb == NULL) {
  77                 fprintf(stderr, "%s: Error opening database %s\n", progname, dbpath);
  78                 return 1;
  79         }
  80
  81         if (tdb_chainlock(tdb, key) < 0) {
  82                 fprintf(stderr, "%s: Error getting record lock (%s)\n",
  83                         progname, tdb_errorstr(tdb));
  84                 return 1;
  85         }
  86
  87         return 0;
  88
  89 }
  90
  91
  92 static int lock_db(const char *dbpath)
  93 {
  94         struct tdb_context *tdb;
  95
  96         tdb = tdb_open(dbpath, 0, TDB_DEFAULT, O_RDWR, 0600);
  97         if (tdb == NULL) {
  98                 fprintf(stderr, "%s: Error opening database %s\n", progname, dbpath);
  99                 return 1;
 100         }
 101
 102         if (tdb_lockall(tdb) < 0) {
 103                 fprintf(stderr, "%s: Error getting db lock (%s)\n",
 104                         progname, tdb_errorstr(tdb));
 105                 return 1;
 106         }
 107
 108         return 0;
 109 }
 110
 111
 112 int main(int argc, char *argv[])
 113 {
 114         int write_fd;
 115         char result = 0;
 116         int ppid;
 117         const char *lock_type;
 118
 119         progname = argv[0];
 120
 121         if (argc < 4) {
 122                 usage();
 123                 exit(1);
 124         }
 125
 126         ppid = atoi(argv[1]);
 127         write_fd = atoi(argv[2]);
 128         lock_type = argv[3];
 129
 130         if (strcmp(lock_type, "RECORD") == 0) {
 131                 if (argc != 6) {
 132                         fprintf(stderr, "%s: Invalid number of arguments (%d)\n",
 133                                 progname, argc);
 134                         usage();
 135                         exit(1);
 136                 }
 137                 result = lock_record(argv[4], argv[5]);
 138
 139         } else if (strcmp(lock_type, "DB") == 0) {
 140                 int n;
 141
 142                 /* If there are no databases specified, no need for lock */
 143                 if (argc > 4) {
 144                         for (n=4; n<argc; n++) {
 145                                 result = lock_db(argv[n]);
 146                                 if (result != 0) {
 147                                         break;
 148                                 }
 149                         }
 150                 }
 151
 152         } else {
 153                 fprintf(stderr, "%s: Invalid lock-type '%s'\n", progname, lock_type);
 154                 usage();
 155                 exit(1);
 156         }
 157
 158         send_result(write_fd, result);
 159
 160         while (kill(ppid, 0) == 0 || errno != ESRCH) {
 161                 sleep(5);
 162         }
 163         return 0;
 164 }