X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb%2Ftest%2Fexternal-agent.c;fp=ccan%2Ftdb%2Ftest%2Fexternal-agent.c;h=dd43c2043f570b364c4b508005c5da77b271cbd7;hp=0000000000000000000000000000000000000000;hb=a153d09b979182e8586d4501ea687bcdd466dabc;hpb=426c8dc977d0fb46286042f7072d86bc053836a1

diff --git a/ccan/tdb/test/external-agent.c b/ccan/tdb/test/external-agent.c
new file mode 100644
index 00000000..dd43c204
--- /dev/null
+++ b/ccan/tdb/test/external-agent.c
@@ -0,0 +1,209 @@
+#include "external-agent.h"
+#include "lock-tracking.h"
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <err.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <string.h>
+#include <errno.h>
+#include <ccan/tdb/tdb.h>
+#include <ccan/tdb/tdb_private.h>
+#include <ccan/tap/tap.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+static struct tdb_context *tdb;
+
+static void taplog(struct tdb_context *tdb,
+		   enum tdb_debug_level level,
+		   const char *fmt, ...)
+{
+	va_list ap;
+	char line[200];
+
+	va_start(ap, fmt);
+	vsprintf(line, fmt, ap);
+	va_end(ap);
+
+	diag("external: %s", line);
+}
+
+static enum agent_return do_operation(enum operation op, const char *name)
+{
+	struct tdb_logging_context logctx = { taplog, NULL };
+	TDB_DATA k;
+	enum agent_return ret;
+	TDB_DATA data;
+
+	if (op != OPEN && op != OPEN_WITH_CLEAR_IF_FIRST && !tdb) {
+		diag("external: No tdb open!");
+		return OTHER_FAILURE;
+	}
+
+	k.dptr = (void *)name;
+	k.dsize = strlen(name);
+
+	locking_would_block = 0;
+	switch (op) {
+	case OPEN:
+		if (tdb) {
+			diag("Already have tdb %s open", tdb_name(tdb));
+			return OTHER_FAILURE;
+		}
+		tdb = tdb_open_ex(name, 0, TDB_DEFAULT, O_RDWR, 0,
+				  &logctx, NULL);
+		if (!tdb) {
+			if (!locking_would_block)
+				diag("Opening tdb gave %s", strerror(errno));
+			ret = OTHER_FAILURE;
+		} else
+			ret = SUCCESS;
+		break;
+	case OPEN_WITH_CLEAR_IF_FIRST:
+		if (tdb)
+			return OTHER_FAILURE;
+		tdb = tdb_open_ex(name, 0, TDB_CLEAR_IF_FIRST, O_RDWR, 0,
+				  &logctx, NULL);
+		ret = tdb ? SUCCESS : OTHER_FAILURE;
+		break;
+	case TRANSACTION_START:
+		ret = tdb_transaction_start(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
+		break;
+	case FETCH:
+		data = tdb_fetch(tdb, k);
+		if (data.dptr == NULL) {
+			if (tdb_error(tdb) == TDB_ERR_NOEXIST)
+				ret = FAILED;
+			else
+				ret = OTHER_FAILURE;
+		} else if (data.dsize != k.dsize
+			   || memcmp(data.dptr, k.dptr, k.dsize) != 0) {
+			ret = OTHER_FAILURE;
+		} else {
+			ret = SUCCESS;
+		}
+		free(data.dptr);
+		break;
+	case STORE:
+		ret = tdb_store(tdb, k, k, 0) == 0 ? SUCCESS : OTHER_FAILURE;
+		break;
+	case TRANSACTION_COMMIT:
+		ret = tdb_transaction_commit(tdb)==0 ? SUCCESS : OTHER_FAILURE;
+		break;
+	case CHECK:
+		ret = tdb_check(tdb, NULL, NULL) == 0 ? SUCCESS : OTHER_FAILURE;
+		break;
+	case NEEDS_RECOVERY:
+		ret = tdb_needs_recovery(tdb) ? SUCCESS : FAILED;
+		break;
+	case CLOSE:
+		ret = tdb_close(tdb) == 0 ? SUCCESS : OTHER_FAILURE;
+		tdb = NULL;
+		break;
+	default:
+		ret = OTHER_FAILURE;
+	}
+
+	if (locking_would_block)
+		ret = WOULD_HAVE_BLOCKED;
+
+	return ret;
+}
+
+struct agent {
+	int cmdfd, responsefd;
+};
+
+/* Do this before doing any tdb stuff.  Return handle, or NULL. */
+struct agent *prepare_external_agent(void)
+{
+	int pid, ret;
+	int command[2], response[2];
+	char name[1+PATH_MAX];
+
+	if (pipe(command) != 0 || pipe(response) != 0)
+		return NULL;
+
+	pid = fork();
+	if (pid < 0)
+		return NULL;
+
+	if (pid != 0) {
+		struct agent *agent = malloc(sizeof(*agent));
+
+		close(command[0]);
+		close(response[1]);
+		agent->cmdfd = command[1];
+		agent->responsefd = response[0];
+		return agent;
+	}
+
+	close(command[1]);
+	close(response[0]);
+
+	/* We want to fail, not block. */
+	nonblocking_locks = true;
+	while ((ret = read(command[0], name, sizeof(name))) > 0) {
+		enum agent_return result;
+
+		result = do_operation(name[0], name+1);
+		if (write(response[1], &result, sizeof(result))
+		    != sizeof(result))
+			err(1, "Writing response");
+	}
+	exit(0);
+}
+
+/* Ask the external agent to try to do an operation. */
+enum agent_return external_agent_operation(struct agent *agent,
+					   enum operation op,
+					   const char *name)
+{
+	enum agent_return res;
+	unsigned int len;
+	char *string;
+
+	if (!name)
+		name = "";
+	len = 1 + strlen(name) + 1;
+	string = malloc(len);
+
+	string[0] = op;
+	strcpy(string+1, name);
+
+	if (write(agent->cmdfd, string, len) != len
+	    || read(agent->responsefd, &res, sizeof(res)) != sizeof(res))
+		res = AGENT_DIED;
+
+	free(string);
+	return res;
+}
+
+const char *agent_return_name(enum agent_return ret)
+{
+	return ret == SUCCESS ? "SUCCESS"
+		: ret == WOULD_HAVE_BLOCKED ? "WOULD_HAVE_BLOCKED"
+		: ret == AGENT_DIED ? "AGENT_DIED"
+		: ret == FAILED ? "FAILED"
+		: ret == OTHER_FAILURE ? "OTHER_FAILURE"
+		: "**INVALID**";
+}
+
+const char *operation_name(enum operation op)
+{
+	switch (op) {
+	case OPEN: return "OPEN";
+	case OPEN_WITH_CLEAR_IF_FIRST: return "OPEN_WITH_CLEAR_IF_FIRST";
+	case TRANSACTION_START: return "TRANSACTION_START";
+	case FETCH: return "FETCH";
+	case STORE: return "STORE";
+	case TRANSACTION_COMMIT: return "TRANSACTION_COMMIT";
+	case CHECK: return "CHECK";
+	case NEEDS_RECOVERY: return "NEEDS_RECOVERY";
+	case CLOSE: return "CLOSE";
+	}
+	return "**INVALID**";
+}