1 #include "external-agent.h"
2 #include "lock-tracking.h"
12 #include "../common/tdb_private.h"
13 #include "tap-interface.h"
17 static struct tdb_context *tdb;
19 static enum agent_return do_operation(enum operation op, const char *name)
22 enum agent_return ret;
25 if (op != OPEN && op != OPEN_WITH_CLEAR_IF_FIRST && !tdb) {
26 diag("external: No tdb open!");
30 k.dptr = discard_const_p(uint8_t, name);
31 k.dsize = strlen(name);
33 locking_would_block = 0;
37 diag("Already have tdb %s open", tdb_name(tdb));
40 tdb = tdb_open_ex(name, 0, TDB_DEFAULT, O_RDWR, 0,
43 if (!locking_would_block)
44 diag("Opening tdb gave %s", strerror(errno));
49 case OPEN_WITH_CLEAR_IF_FIRST:
52 tdb = tdb_open_ex(name, 0, TDB_CLEAR_IF_FIRST, O_RDWR, 0,
54 ret = tdb ? SUCCESS : OTHER_FAILURE;
56 case TRANSACTION_START:
57 ret = tdb_transaction_start(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
60 data = tdb_fetch(tdb, k);
61 if (data.dptr == NULL) {
62 if (tdb_error(tdb) == TDB_ERR_NOEXIST)
66 } else if (data.dsize != k.dsize
67 || memcmp(data.dptr, k.dptr, k.dsize) != 0) {
75 ret = tdb_store(tdb, k, k, 0) == 0 ? SUCCESS : OTHER_FAILURE;
77 case TRANSACTION_COMMIT:
78 ret = tdb_transaction_commit(tdb)==0 ? SUCCESS : OTHER_FAILURE;
81 ret = tdb_check(tdb, NULL, NULL) == 0 ? SUCCESS : OTHER_FAILURE;
84 ret = tdb_needs_recovery(tdb) ? SUCCESS : FAILED;
87 ret = tdb_close(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
94 ret = tdb_munmap(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
96 tdb->flags |= TDB_NOMMAP;
103 if (locking_would_block)
104 ret = WOULD_HAVE_BLOCKED;
110 int cmdfd, responsefd;
114 /* Do this before doing any tdb stuff. Return handle, or NULL. */
115 struct agent *prepare_external_agent(void)
118 int command[2], response[2];
119 char name[1+PATH_MAX];
120 struct agent *agent = malloc(sizeof(*agent));
122 if (pipe(command) != 0 || pipe(response) != 0) {
123 fprintf(stderr, "pipe failed: %s\n", strerror(errno));
128 if (agent->pid < 0) {
129 fprintf(stderr, "fork failed: %s\n", strerror(errno));
133 if (agent->pid != 0) {
136 agent->cmdfd = command[1];
137 agent->responsefd = response[0];
144 /* We want to fail, not block. */
145 nonblocking_locks = true;
146 log_prefix = "external: ";
147 while ((ret = read(command[0], name, sizeof(name))) > 0) {
148 enum agent_return result;
150 result = do_operation(name[0], name+1);
151 if (write(response[1], &result, sizeof(result))
158 void shutdown_agent(struct agent *agent)
163 close(agent->responsefd);
164 p = waitpid(agent->pid, NULL, WNOHANG);
166 kill(agent->pid, SIGKILL);
168 waitpid(agent->pid, NULL, 0);
172 /* Ask the external agent to try to do an operation. */
173 enum agent_return external_agent_operation(struct agent *agent,
177 enum agent_return res;
183 len = 1 + strlen(name) + 1;
184 string = malloc(len);
187 strncpy(string+1, name, len - 1);
188 string[len-1] = '\0';
190 if (write(agent->cmdfd, string, len) != len
191 || read(agent->responsefd, &res, sizeof(res)) != sizeof(res))
198 const char *agent_return_name(enum agent_return ret)
200 return ret == SUCCESS ? "SUCCESS"
201 : ret == WOULD_HAVE_BLOCKED ? "WOULD_HAVE_BLOCKED"
202 : ret == AGENT_DIED ? "AGENT_DIED"
203 : ret == FAILED ? "FAILED"
204 : ret == OTHER_FAILURE ? "OTHER_FAILURE"
208 const char *operation_name(enum operation op)
211 case OPEN: return "OPEN";
212 case OPEN_WITH_CLEAR_IF_FIRST: return "OPEN_WITH_CLEAR_IF_FIRST";
213 case TRANSACTION_START: return "TRANSACTION_START";
214 case FETCH: return "FETCH";
215 case STORE: return "STORE";
216 case TRANSACTION_COMMIT: return "TRANSACTION_COMMIT";
217 case CHECK: return "CHECK";
218 case NEEDS_RECOVERY: return "NEEDS_RECOVERY";
219 case CLOSE: return "CLOSE";
220 case PING: return "PING";
221 case UNMAP: return "UNMAP";
223 return "**INVALID**";