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 if (locking_would_block)
95 ret = WOULD_HAVE_BLOCKED;
101 int cmdfd, responsefd;
105 /* Do this before doing any tdb stuff. Return handle, or NULL. */
106 struct agent *prepare_external_agent(void)
109 int command[2], response[2];
110 char name[1+PATH_MAX];
111 struct agent *agent = malloc(sizeof(*agent));
113 if (pipe(command) != 0 || pipe(response) != 0) {
114 fprintf(stderr, "pipe failed: %s\n", strerror(errno));
119 if (agent->pid < 0) {
120 fprintf(stderr, "fork failed: %s\n", strerror(errno));
124 if (agent->pid != 0) {
127 agent->cmdfd = command[1];
128 agent->responsefd = response[0];
135 /* We want to fail, not block. */
136 nonblocking_locks = true;
137 log_prefix = "external: ";
138 while ((ret = read(command[0], name, sizeof(name))) > 0) {
139 enum agent_return result;
141 result = do_operation(name[0], name+1);
142 if (write(response[1], &result, sizeof(result))
149 void shutdown_agent(struct agent *agent)
154 close(agent->responsefd);
155 p = waitpid(agent->pid, NULL, WNOHANG);
157 kill(agent->pid, SIGKILL);
159 waitpid(agent->pid, NULL, 0);
163 /* Ask the external agent to try to do an operation. */
164 enum agent_return external_agent_operation(struct agent *agent,
168 enum agent_return res;
174 len = 1 + strlen(name) + 1;
175 string = malloc(len);
178 strcpy(string+1, name);
180 if (write(agent->cmdfd, string, len) != len
181 || read(agent->responsefd, &res, sizeof(res)) != sizeof(res))
188 const char *agent_return_name(enum agent_return ret)
190 return ret == SUCCESS ? "SUCCESS"
191 : ret == WOULD_HAVE_BLOCKED ? "WOULD_HAVE_BLOCKED"
192 : ret == AGENT_DIED ? "AGENT_DIED"
193 : ret == FAILED ? "FAILED"
194 : ret == OTHER_FAILURE ? "OTHER_FAILURE"
198 const char *operation_name(enum operation op)
201 case OPEN: return "OPEN";
202 case OPEN_WITH_CLEAR_IF_FIRST: return "OPEN_WITH_CLEAR_IF_FIRST";
203 case TRANSACTION_START: return "TRANSACTION_START";
204 case FETCH: return "FETCH";
205 case STORE: return "STORE";
206 case TRANSACTION_COMMIT: return "TRANSACTION_COMMIT";
207 case CHECK: return "CHECK";
208 case NEEDS_RECOVERY: return "NEEDS_RECOVERY";
209 case CLOSE: return "CLOSE";
211 return "**INVALID**";