lib/tdb2/test/tdb1-external-agent.c

   1 #include "tdb1-external-agent.h"
   2 #include "tdb1-lock-tracking.h"
   3 #include "logging.h"
   4 #include <sys/types.h>
   5 #include <sys/wait.h>
   6 #include <unistd.h>
   7 #include <fcntl.h>
   8 #include <stdlib.h>
   9 #include <limits.h>
  10 #include <string.h>
  11 #include <errno.h>
  12 #include "tdb1_private.h"
  13 #include "tap-interface.h"
  14 #include <stdio.h>
  15 #include <stdarg.h>
  16
  17 static struct tdb_context *tdb;
  18
  19 static enum agent_return do_operation(enum operation op, const char *name)
  20 {
  21         TDB_DATA k;
  22         enum agent_return ret;
  23         TDB_DATA data;
  24
  25         if (op != OPEN && !tdb) {
  26                 diag("external: No tdb open!");
  27                 return OTHER_FAILURE;
  28         }
  29
  30         k = tdb_mkdata(name, strlen(name));
  31
  32         locking_would_block1 = 0;
  33         switch (op) {
  34         case OPEN:
  35                 if (tdb) {
  36                         diag("Already have tdb %s open", tdb->name);
  37                         return OTHER_FAILURE;
  38                 }
  39                 tdb = tdb_open(name, TDB_VERSION1, O_RDWR, 0, &tap_log_attr);
  40                 if (!tdb) {
  41                         if (!locking_would_block1)
  42                                 diag("Opening tdb gave %s", strerror(errno));
  43                         ret = OTHER_FAILURE;
  44                 } else
  45                         ret = SUCCESS;
  46                 break;
  47         case TRANSACTION_START:
  48                 ret = tdb_transaction_start(tdb) == TDB_SUCCESS ? SUCCESS : OTHER_FAILURE;
  49                 break;
  50         case FETCH:
  51                 if (tdb_fetch(tdb, k, &data) != TDB_SUCCESS) {
  52                         if (tdb->last_error == TDB_ERR_NOEXIST)
  53                                 ret = FAILED;
  54                         else
  55                                 ret = OTHER_FAILURE;
  56                 } else if (data.dsize != k.dsize
  57                            || memcmp(data.dptr, k.dptr, k.dsize) != 0) {
  58                         ret = OTHER_FAILURE;
  59                 } else {
  60                         ret = SUCCESS;
  61                 }
  62                 free(data.dptr);
  63                 break;
  64         case STORE:
  65                 if (tdb_store(tdb, k, k, 0) == TDB_SUCCESS)
  66                         ret = SUCCESS;
  67                 else
  68                         ret = OTHER_FAILURE;
  69                 break;
  70         case TRANSACTION_COMMIT:
  71                 ret = tdb_transaction_commit(tdb) == TDB_SUCCESS ? SUCCESS : OTHER_FAILURE;
  72                 break;
  73         case CHECK:
  74                 ret = tdb_check(tdb, NULL, NULL) == TDB_SUCCESS ? SUCCESS : OTHER_FAILURE;
  75                 break;
  76         case NEEDS_RECOVERY:
  77                 ret = external_agent_needs_rec(tdb);
  78                 break;
  79         case CLOSE:
  80                 ret = tdb_close(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
  81                 tdb = NULL;
  82                 break;
  83         default:
  84                 ret = OTHER_FAILURE;
  85         }
  86
  87         if (locking_would_block1)
  88                 ret = WOULD_HAVE_BLOCKED;
  89
  90         return ret;
  91 }
  92
  93 struct agent {
  94         int cmdfd, responsefd;
  95 };
  96
  97 /* Do this before doing any tdb stuff.  Return handle, or NULL. */
  98 struct agent *prepare_external_agent1(void)
  99 {
 100         int pid, ret;
 101         int command[2], response[2];
 102         char name[1+PATH_MAX];
 103
 104         if (pipe(command) != 0 || pipe(response) != 0)
 105                 return NULL;
 106
 107         pid = fork();
 108         if (pid < 0)
 109                 return NULL;
 110
 111         if (pid != 0) {
 112                 struct agent *agent = malloc(sizeof(*agent));
 113
 114                 close(command[0]);
 115                 close(response[1]);
 116                 agent->cmdfd = command[1];
 117                 agent->responsefd = response[0];
 118                 return agent;
 119         }
 120
 121         close(command[1]);
 122         close(response[0]);
 123
 124         /* We want to fail, not block. */
 125         nonblocking_locks1 = true;
 126         log_prefix = "external: ";
 127         while ((ret = read(command[0], name, sizeof(name))) > 0) {
 128                 enum agent_return result;
 129
 130                 result = do_operation(name[0], name+1);
 131                 if (write(response[1], &result, sizeof(result))
 132                     != sizeof(result))
 133                         err(1, "Writing response");
 134         }
 135         exit(0);
 136 }
 137
 138 /* Ask the external agent to try to do an operation. */
 139 enum agent_return external_agent_operation1(struct agent *agent,
 140                                            enum operation op,
 141                                            const char *name)
 142 {
 143         enum agent_return res;
 144         unsigned int len;
 145         char *string;
 146
 147         if (!name)
 148                 name = "";
 149         len = 1 + strlen(name) + 1;
 150         string = malloc(len);
 151
 152         string[0] = op;
 153         strcpy(string+1, name);
 154
 155         if (write(agent->cmdfd, string, len) != len
 156             || read(agent->responsefd, &res, sizeof(res)) != sizeof(res))
 157                 res = AGENT_DIED;
 158
 159         free(string);
 160         return res;
 161 }
 162
 163 const char *agent_return_name1(enum agent_return ret)
 164 {
 165         return ret == SUCCESS ? "SUCCESS"
 166                 : ret == WOULD_HAVE_BLOCKED ? "WOULD_HAVE_BLOCKED"
 167                 : ret == AGENT_DIED ? "AGENT_DIED"
 168                 : ret == FAILED ? "FAILED"
 169                 : ret == OTHER_FAILURE ? "OTHER_FAILURE"
 170                 : "**INVALID**";
 171 }
 172
 173 const char *operation_name1(enum operation op)
 174 {
 175         switch (op) {
 176         case OPEN: return "OPEN";
 177         case TRANSACTION_START: return "TRANSACTION_START";
 178         case FETCH: return "FETCH";
 179         case STORE: return "STORE";
 180         case TRANSACTION_COMMIT: return "TRANSACTION_COMMIT";
 181         case CHECK: return "CHECK";
 182         case NEEDS_RECOVERY: return "NEEDS_RECOVERY";
 183         case CLOSE: return "CLOSE";
 184         }
 185         return "**INVALID**";
 186 }