1 #include "external-agent.h"
3 #include "lock-tracking.h"
13 #include <ccan/tdb2/private.h>
14 #include <ccan/tap/tap.h>
18 static struct tdb_context *tdb;
20 static enum agent_return do_operation(enum operation op, const char *name)
23 enum agent_return ret;
27 if (op != OPEN && !tdb) {
28 diag("external: No tdb open!");
32 diag("external: %s", operation_name(op));
34 k = tdb_mkdata(name, strlen(name));
36 locking_would_block = 0;
40 diag("Already have tdb %s open", tdb->name);
43 tdb = tdb_open(name, TDB_DEFAULT, O_RDWR, 0, &tap_log_attr);
45 if (!locking_would_block)
46 diag("Opening tdb gave %s", strerror(errno));
53 ecode = tdb_fetch(tdb, k, &data);
54 if (ecode == TDB_ERR_NOEXIST) {
56 } else if (ecode < 0) {
58 } else if (!tdb_deq(data, k)) {
67 ret = tdb_store(tdb, k, k, 0) == 0 ? SUCCESS : OTHER_FAILURE;
69 case TRANSACTION_START:
70 ret = tdb_transaction_start(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
72 case TRANSACTION_COMMIT:
73 ret = tdb_transaction_commit(tdb)==0 ? SUCCESS : OTHER_FAILURE;
76 ret = tdb_needs_recovery(tdb) ? SUCCESS : FAILED;
79 ret = tdb_check(tdb, NULL, NULL) == 0 ? SUCCESS : OTHER_FAILURE;
82 ret = tdb_close(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
89 if (locking_would_block)
90 ret = WOULD_HAVE_BLOCKED;
96 int cmdfd, responsefd;
99 /* Do this before doing any tdb stuff. Return handle, or NULL. */
100 struct agent *prepare_external_agent(void)
103 int command[2], response[2];
104 char name[1+PATH_MAX];
106 if (pipe(command) != 0 || pipe(response) != 0)
114 struct agent *agent = malloc(sizeof(*agent));
118 agent->cmdfd = command[1];
119 agent->responsefd = response[0];
126 /* We want to fail, not block. */
127 nonblocking_locks = true;
128 log_prefix = "external: ";
129 while ((ret = read(command[0], name, sizeof(name))) > 0) {
130 enum agent_return result;
132 result = do_operation(name[0], name+1);
133 if (write(response[1], &result, sizeof(result))
135 err(1, "Writing response");
140 /* Ask the external agent to try to do an operation. */
141 enum agent_return external_agent_operation(struct agent *agent,
145 enum agent_return res;
151 len = 1 + strlen(name) + 1;
152 string = malloc(len);
155 strcpy(string+1, name);
157 if (write(agent->cmdfd, string, len) != len
158 || read(agent->responsefd, &res, sizeof(res)) != sizeof(res))
165 const char *agent_return_name(enum agent_return ret)
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"
175 const char *operation_name(enum operation op)
178 case OPEN: return "OPEN";
179 case FETCH: return "FETCH";
180 case STORE: return "STORE";
181 case CHECK: return "CHECK";
182 case TRANSACTION_START: return "TRANSACTION_START";
183 case TRANSACTION_COMMIT: return "TRANSACTION_COMMIT";
184 case NEEDS_RECOVERY: return "NEEDS_RECOVERY";
185 case CLOSE: return "CLOSE";
187 return "**INVALID**";
190 void free_external_agent(struct agent *agent)
193 close(agent->responsefd);