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 <err.h>
   8 #include <fcntl.h>
   9 #include <stdlib.h>
  10 #include <limits.h>
  11 #include <string.h>
  12 #include <errno.h>
  13 #include <ccan/tdb2/tdb1_private.h>
  14 #include <ccan/tap/tap.h>
  15 #include <stdio.h>
  16 #include <stdarg.h>
  17
  18 static struct tdb_context *tdb;
  19
  20 static enum agent_return do_operation(enum operation op, const char *name)
  21 {
  22         TDB_DATA k;
  23         enum agent_return ret;
  24         TDB_DATA data;
  25
  26         if (op != OPEN && !tdb) {
  27                 diag("external: No tdb open!");
  28                 return OTHER_FAILURE;
  29         }
  30
  31         k.dptr = (void *)name;
  32         k.dsize = strlen(name);
  33
  34         locking_would_block1 = 0;
  35         switch (op) {
  36         case OPEN:
  37                 if (tdb) {
  38                         diag("Already have tdb %s open", tdb->name);
  39                         return OTHER_FAILURE;
  40                 }
  41                 tdb = tdb_open(name, TDB_VERSION1, O_RDWR, 0, &tap_log_attr);
  42                 if (!tdb) {
  43                         if (!locking_would_block1)
  44                                 diag("Opening tdb gave %s", strerror(errno));
  45                         ret = OTHER_FAILURE;
  46                 } else
  47                         ret = SUCCESS;
  48                 break;
  49         case TRANSACTION_START:
  50                 ret = tdb_transaction_start(tdb) == TDB_SUCCESS ? SUCCESS : OTHER_FAILURE;
  51                 break;
  52         case FETCH:
  53                 if (tdb_fetch(tdb, k, &data) != TDB_SUCCESS) {
  54                         if (tdb->last_error == TDB_ERR_NOEXIST)
  55                                 ret = FAILED;
  56                         else
  57                                 ret = OTHER_FAILURE;
  58                 } else if (data.dsize != k.dsize
  59                            || memcmp(data.dptr, k.dptr, k.dsize) != 0) {
  60                         ret = OTHER_FAILURE;
  61                 } else {
  62                         ret = SUCCESS;
  63                 }
  64                 free(data.dptr);
  65                 break;
  66         case STORE:
  67                 if (tdb_store(tdb, k, k, 0) == TDB_SUCCESS)
  68                         ret = SUCCESS;
  69                 else
  70                         ret = OTHER_FAILURE;
  71                 break;
  72         case TRANSACTION_COMMIT:
  73                 ret = tdb_transaction_commit(tdb) == TDB_SUCCESS ? SUCCESS : OTHER_FAILURE;
  74                 break;
  75         case CHECK:
  76                 ret = tdb_check(tdb, NULL, NULL) == TDB_SUCCESS ? SUCCESS : OTHER_FAILURE;
  77                 break;
  78         case NEEDS_RECOVERY:
  79                 ret = tdb1_needs_recovery(tdb) ? SUCCESS : FAILED;
  80                 break;
  81         case CLOSE:
  82                 ret = tdb_close(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
  83                 tdb = NULL;
  84                 break;
  85         default:
  86                 ret = OTHER_FAILURE;
  87         }
  88
  89         if (locking_would_block1)
  90                 ret = WOULD_HAVE_BLOCKED;
  91
  92         return ret;
  93 }
  94
  95 struct agent {
  96         int cmdfd, responsefd;
  97 };
  98
  99 /* Do this before doing any tdb stuff.  Return handle, or NULL. */
 100 struct agent *prepare_external_agent1(void)
 101 {
 102         int pid, ret;
 103         int command[2], response[2];
 104         char name[1+PATH_MAX];
 105
 106         if (pipe(command) != 0 || pipe(response) != 0)
 107                 return NULL;
 108
 109         pid = fork();
 110         if (pid < 0)
 111                 return NULL;
 112
 113         if (pid != 0) {
 114                 struct agent *agent = malloc(sizeof(*agent));
 115
 116                 close(command[0]);
 117                 close(response[1]);
 118                 agent->cmdfd = command[1];
 119                 agent->responsefd = response[0];
 120                 return agent;
 121         }
 122
 123         close(command[1]);
 124         close(response[0]);
 125
 126         /* We want to fail, not block. */
 127         nonblocking_locks1 = true;
 128         log_prefix = "external: ";
 129         while ((ret = read(command[0], name, sizeof(name))) > 0) {
 130                 enum agent_return result;
 131
 132                 result = do_operation(name[0], name+1);
 133                 if (write(response[1], &result, sizeof(result))
 134                     != sizeof(result))
 135                         err(1, "Writing response");
 136         }
 137         exit(0);
 138 }
 139
 140 /* Ask the external agent to try to do an operation. */
 141 enum agent_return external_agent_operation1(struct agent *agent,
 142                                            enum operation op,
 143                                            const char *name)
 144 {
 145         enum agent_return res;
 146         unsigned int len;
 147         char *string;
 148
 149         if (!name)
 150                 name = "";
 151         len = 1 + strlen(name) + 1;
 152         string = malloc(len);
 153
 154         string[0] = op;
 155         strcpy(string+1, name);
 156
 157         if (write(agent->cmdfd, string, len) != len
 158             || read(agent->responsefd, &res, sizeof(res)) != sizeof(res))
 159                 res = AGENT_DIED;
 160
 161         free(string);
 162         return res;
 163 }
 164
 165 const char *agent_return_name1(enum agent_return ret)
 166 {
 167         return ret == SUCCESS ? "SUCCESS"
 168                 : ret == WOULD_HAVE_BLOCKED ? "WOULD_HAVE_BLOCKED"
 169                 : ret == AGENT_DIED ? "AGENT_DIED"
 170                 : ret == FAILED ? "FAILED"
 171                 : ret == OTHER_FAILURE ? "OTHER_FAILURE"
 172                 : "**INVALID**";
 173 }
 174
 175 const char *operation_name1(enum operation op)
 176 {
 177         switch (op) {
 178         case OPEN: return "OPEN";
 179         case TRANSACTION_START: return "TRANSACTION_START";
 180         case FETCH: return "FETCH";
 181         case STORE: return "STORE";
 182         case TRANSACTION_COMMIT: return "TRANSACTION_COMMIT";
 183         case CHECK: return "CHECK";
 184         case NEEDS_RECOVERY: return "NEEDS_RECOVERY";
 185         case CLOSE: return "CLOSE";
 186         }
 187         return "**INVALID**";
 188 }