1 #include "external-agent.h"
2 #include "lock-tracking.h"
12 #include <ccan/tdb/tdb.h>
13 #include <ccan/tdb/tdb_private.h>
14 #include <ccan/tap/tap.h>
18 static struct tdb_context *tdb;
20 static void taplog(struct tdb_context *tdb,
21 enum tdb_debug_level level,
28 vsprintf(line, fmt, ap);
31 diag("external: %s", line);
34 static enum agent_return do_operation(enum operation op, const char *name)
36 struct tdb_logging_context logctx = { taplog, NULL };
38 enum agent_return ret;
41 if (op != OPEN && op != OPEN_WITH_CLEAR_IF_FIRST && !tdb) {
42 diag("external: No tdb open!");
46 k.dptr = (void *)name;
47 k.dsize = strlen(name);
49 locking_would_block = 0;
53 diag("Already have tdb %s open", tdb_name(tdb));
56 tdb = tdb_open_ex(name, 0, TDB_DEFAULT, O_RDWR, 0,
59 if (!locking_would_block)
60 diag("Opening tdb gave %s", strerror(errno));
65 case OPEN_WITH_CLEAR_IF_FIRST:
68 tdb = tdb_open_ex(name, 0, TDB_CLEAR_IF_FIRST, O_RDWR, 0,
70 ret = tdb ? SUCCESS : OTHER_FAILURE;
72 case TRANSACTION_START:
73 ret = tdb_transaction_start(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
76 data = tdb_fetch(tdb, k);
77 if (data.dptr == NULL) {
78 if (tdb_error(tdb) == TDB_ERR_NOEXIST)
82 } else if (data.dsize != k.dsize
83 || memcmp(data.dptr, k.dptr, k.dsize) != 0) {
91 ret = tdb_store(tdb, k, k, 0) == 0 ? SUCCESS : OTHER_FAILURE;
93 case TRANSACTION_COMMIT:
94 ret = tdb_transaction_commit(tdb)==0 ? SUCCESS : OTHER_FAILURE;
97 ret = tdb_check(tdb, NULL, NULL) == 0 ? SUCCESS : OTHER_FAILURE;
100 ret = tdb_needs_recovery(tdb) ? SUCCESS : FAILED;
103 ret = tdb_close(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
110 if (locking_would_block)
111 ret = WOULD_HAVE_BLOCKED;
117 int cmdfd, responsefd;
120 /* Do this before doing any tdb stuff. Return handle, or NULL. */
121 struct agent *prepare_external_agent(void)
124 int command[2], response[2];
125 char name[1+PATH_MAX];
127 if (pipe(command) != 0 || pipe(response) != 0)
135 struct agent *agent = malloc(sizeof(*agent));
139 agent->cmdfd = command[1];
140 agent->responsefd = response[0];
147 /* We want to fail, not block. */
148 nonblocking_locks = true;
149 while ((ret = read(command[0], name, sizeof(name))) > 0) {
150 enum agent_return result;
152 result = do_operation(name[0], name+1);
153 if (write(response[1], &result, sizeof(result))
155 err(1, "Writing response");
160 /* Ask the external agent to try to do an operation. */
161 enum agent_return external_agent_operation(struct agent *agent,
165 enum agent_return res;
171 len = 1 + strlen(name) + 1;
172 string = malloc(len);
175 strcpy(string+1, name);
177 if (write(agent->cmdfd, string, len) != len
178 || read(agent->responsefd, &res, sizeof(res)) != sizeof(res))
185 const char *agent_return_name(enum agent_return ret)
187 return ret == SUCCESS ? "SUCCESS"
188 : ret == WOULD_HAVE_BLOCKED ? "WOULD_HAVE_BLOCKED"
189 : ret == AGENT_DIED ? "AGENT_DIED"
190 : ret == FAILED ? "FAILED"
191 : ret == OTHER_FAILURE ? "OTHER_FAILURE"
195 const char *operation_name(enum operation op)
198 case OPEN: return "OPEN";
199 case OPEN_WITH_CLEAR_IF_FIRST: return "OPEN_WITH_CLEAR_IF_FIRST";
200 case TRANSACTION_START: return "TRANSACTION_START";
201 case FETCH: return "FETCH";
202 case STORE: return "STORE";
203 case TRANSACTION_COMMIT: return "TRANSACTION_COMMIT";
204 case CHECK: return "CHECK";
205 case NEEDS_RECOVERY: return "NEEDS_RECOVERY";
206 case CLOSE: return "CLOSE";
208 return "**INVALID**";