Line data    Source code

       1             : #include "external-agent.h"
       2             : #include "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 "../common/tdb_private.h"
      13             : #include "tap-interface.h"
      14             : #include <stdio.h>
      15             : #include <stdarg.h>
      16             : 
      17             : static struct tdb_context *tdb;
      18             : 
      19         410 : 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         410 :         if (op != OPEN && op != OPEN_WITH_CLEAR_IF_FIRST && !tdb) {
      26           0 :                 diag("external: No tdb open!");
      27           0 :                 return OTHER_FAILURE;
      28             :         }
      29             : 
      30         410 :         k.dptr = discard_const_p(uint8_t, name);
      31         410 :         k.dsize = strlen(name);
      32             : 
      33         410 :         locking_would_block = 0;
      34         410 :         switch (op) {
      35          68 :         case OPEN:
      36          68 :                 if (tdb) {
      37           0 :                         diag("Already have tdb %s open", tdb_name(tdb));
      38           0 :                         return OTHER_FAILURE;
      39             :                 }
      40          68 :                 tdb = tdb_open_ex(name, 0, TDB_DEFAULT, O_RDWR, 0,
      41             :                                   &taplogctx, NULL);
      42          68 :                 if (!tdb) {
      43          10 :                         if (!locking_would_block)
      44           0 :                                 diag("Opening tdb gave %s", strerror(errno));
      45          10 :                         ret = OTHER_FAILURE;
      46             :                 } else
      47          58 :                         ret = SUCCESS;
      48          68 :                 break;
      49          12 :         case OPEN_WITH_CLEAR_IF_FIRST:
      50          12 :                 if (tdb)
      51           0 :                         return OTHER_FAILURE;
      52          12 :                 tdb = tdb_open_ex(name, 0, TDB_CLEAR_IF_FIRST, O_RDWR, 0,
      53             :                                   &taplogctx, NULL);
      54          12 :                 ret = tdb ? SUCCESS : OTHER_FAILURE;
      55          12 :                 break;
      56          26 :         case TRANSACTION_START:
      57          26 :                 ret = tdb_transaction_start(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
      58          26 :                 break;
      59          71 :         case FETCH:
      60          71 :                 data = tdb_fetch(tdb, k);
      61          71 :                 if (data.dptr == NULL) {
      62           0 :                         if (tdb_error(tdb) == TDB_ERR_NOEXIST)
      63           0 :                                 ret = FAILED;
      64             :                         else
      65           0 :                                 ret = OTHER_FAILURE;
      66          71 :                 } else if (data.dsize != k.dsize
      67          71 :                            || memcmp(data.dptr, k.dptr, k.dsize) != 0) {
      68           0 :                         ret = OTHER_FAILURE;
      69             :                 } else {
      70          71 :                         ret = SUCCESS;
      71             :                 }
      72          71 :                 free(data.dptr);
      73          71 :                 break;
      74          19 :         case STORE:
      75          19 :                 ret = tdb_store(tdb, k, k, 0) == 0 ? SUCCESS : OTHER_FAILURE;
      76          19 :                 break;
      77           3 :         case TRANSACTION_COMMIT:
      78           3 :                 ret = tdb_transaction_commit(tdb)==0 ? SUCCESS : OTHER_FAILURE;
      79           3 :                 break;
      80          51 :         case CHECK:
      81          51 :                 ret = tdb_check(tdb, NULL, NULL) == 0 ? SUCCESS : OTHER_FAILURE;
      82          51 :                 break;
      83         102 :         case NEEDS_RECOVERY:
      84         102 :                 ret = tdb_needs_recovery(tdb) ? SUCCESS : FAILED;
      85         102 :                 break;
      86          58 :         case CLOSE:
      87          58 :                 ret = tdb_close(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
      88          58 :                 tdb = NULL;
      89          58 :                 break;
      90           0 :         case PING:
      91           0 :                 ret = SUCCESS;
      92           0 :                 break;
      93           0 :         case UNMAP:
      94           0 :                 ret = tdb_munmap(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
      95           0 :                 if (ret == SUCCESS) {
      96           0 :                         tdb->flags |= TDB_NOMMAP;
      97             :                 }
      98           0 :                 break;
      99           0 :         default:
     100           0 :                 ret = OTHER_FAILURE;
     101             :         }
     102             : 
     103         410 :         if (locking_would_block)
     104          27 :                 ret = WOULD_HAVE_BLOCKED;
     105             : 
     106         410 :         return ret;
     107             : }
     108             : 
     109             : struct agent {
     110             :         int cmdfd, responsefd;
     111             :         pid_t pid;
     112             : };
     113             : 
     114             : /* Do this before doing any tdb stuff.  Return handle, or NULL. */
     115          37 : struct agent *prepare_external_agent(void)
     116             : {
     117             :         int ret;
     118             :         int command[2], response[2];
     119             :         char name[1+PATH_MAX];
     120          37 :         struct agent *agent = malloc(sizeof(*agent));
     121             : 
     122          37 :         if (pipe(command) != 0 || pipe(response) != 0) {
     123           0 :                 fprintf(stderr, "pipe failed: %s\n", strerror(errno));
     124           0 :                 exit(1);
     125             :         }
     126             : 
     127          37 :         agent->pid = fork();
     128          41 :         if (agent->pid < 0) {
     129           0 :                 fprintf(stderr, "fork failed: %s\n", strerror(errno));
     130           0 :                 exit(1);
     131             :         }
     132             : 
     133          41 :         if (agent->pid != 0) {
     134          37 :                 close(command[0]);
     135          37 :                 close(response[1]);
     136          37 :                 agent->cmdfd = command[1];
     137          37 :                 agent->responsefd = response[0];
     138          37 :                 return agent;
     139             :         }
     140             : 
     141           4 :         close(command[1]);
     142           4 :         close(response[0]);
     143             : 
     144             :         /* We want to fail, not block. */
     145           4 :         nonblocking_locks = true;
     146           4 :         log_prefix = "external: ";
     147         414 :         while ((ret = read(command[0], name, sizeof(name))) > 0) {
     148             :                 enum agent_return result;
     149             : 
     150         410 :                 result = do_operation(name[0], name+1);
     151         410 :                 if (write(response[1], &result, sizeof(result))
     152             :                     != sizeof(result))
     153           0 :                         abort();
     154             :         }
     155           4 :         exit(0);
     156             : }
     157             : 
     158          33 : void shutdown_agent(struct agent *agent)
     159             : {
     160             :         pid_t p;
     161             : 
     162          33 :         close(agent->cmdfd);
     163          33 :         close(agent->responsefd);
     164          33 :         p = waitpid(agent->pid, NULL, WNOHANG);
     165          33 :         if (p == 0) {
     166           1 :                 kill(agent->pid, SIGKILL);
     167             :         }
     168          33 :         waitpid(agent->pid, NULL, 0);
     169          33 :         free(agent);
     170          33 : }
     171             : 
     172             : /* Ask the external agent to try to do an operation. */
     173         532 : enum agent_return external_agent_operation(struct agent *agent,
     174             :                                            enum operation op,
     175             :                                            const char *name)
     176             : {
     177             :         enum agent_return res;
     178             :         unsigned int len;
     179             :         char *string;
     180             : 
     181         532 :         if (!name)
     182           4 :                 name = "";
     183         532 :         len = 1 + strlen(name) + 1;
     184         532 :         string = malloc(len);
     185             : 
     186         532 :         string[0] = op;
     187         532 :         strncpy(string+1, name, len - 1);
     188         532 :         string[len-1] = '\0';
     189             : 
     190         532 :         if (write(agent->cmdfd, string, len) != len
     191         532 :             || read(agent->responsefd, &res, sizeof(res)) != sizeof(res))
     192          32 :                 res = AGENT_DIED;
     193             : 
     194         532 :         free(string);
     195         532 :         return res;
     196             : }
     197             : 
     198          65 : const char *agent_return_name(enum agent_return ret)
     199             : {
     200             :         return ret == SUCCESS ? "SUCCESS"
     201         129 :                 : ret == WOULD_HAVE_BLOCKED ? "WOULD_HAVE_BLOCKED"
     202         128 :                 : ret == AGENT_DIED ? "AGENT_DIED"
     203          64 :                 : ret == FAILED ? "FAILED"
     204           0 :                 : ret == OTHER_FAILURE ? "OTHER_FAILURE"
     205           0 :                 : "**INVALID**";
     206             : }
     207             : 
     208           3 : const char *operation_name(enum operation op)
     209             : {
     210           3 :         switch (op) {
     211           0 :         case OPEN: return "OPEN";
     212           0 :         case OPEN_WITH_CLEAR_IF_FIRST: return "OPEN_WITH_CLEAR_IF_FIRST";
     213           1 :         case TRANSACTION_START: return "TRANSACTION_START";
     214           1 :         case FETCH: return "FETCH";
     215           1 :         case STORE: return "STORE";
     216           0 :         case TRANSACTION_COMMIT: return "TRANSACTION_COMMIT";
     217           0 :         case CHECK: return "CHECK";
     218           0 :         case NEEDS_RECOVERY: return "NEEDS_RECOVERY";
     219           0 :         case CLOSE: return "CLOSE";
     220           0 :         case PING: return "PING";
     221           0 :         case UNMAP: return "UNMAP";
     222             :         }
     223           0 :         return "**INVALID**";
     224             : }