Add cacheid

The idea is to allow a client to disconnect
and reconnect without losing its cache.

Change-Id: I017176e5eb5f553b961a32ee466d1b7a175532bb
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

11 files changed, 116 insertions, 41 deletions

diff --git a/src/agent-at.c b/src/agent-at.c
index f671fc7..02bcc6c 100644
--- a/src/agent-at.c
+++ b/src/agent-at.c
@@ -16,6 +16,7 @@
  */
 
 #include <stdlib.h>
+#include <stdint.h>
 #include <stdbool.h>
 #include <time.h>
 #include <string.h>
diff --git a/src/cache.c b/src/cache.c
index b57536d..c8e7550 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -60,10 +60,11 @@ typedef struct item item_t;
 /**
  * The cache structure is a blob of memory ('content')
  * of 'count' bytes of only 'used' bytes.
- * That blob containts at sequence of records of variable length
+ * That blob contains at sequence of records of variable length
  */
 struct cache
 {
+	uint32_t cacheid;
 	uint32_t used;
 	uint32_t count;
 	uint8_t content[1];
@@ -264,10 +265,13 @@ cache_search(
 
 void
 cache_clear(
-	cache_t *cache
+	cache_t *cache,
+	uint32_t cacheid
 ) {
-	if (cache)
+	if (cache && (!cacheid || cache->cacheid != cacheid)) {
+		cache->cacheid = cacheid;
 		cache->used = 0;
+	}
 }
 
 int
@@ -286,8 +290,10 @@ cache_resize(
 		return -ENOMEM;
 
 	nc->count = newsize;
-	if (!c)
+	if (!c) {
+		nc->cacheid = 0;
 		nc->used = 0;
+	}
 	*cache = nc;
 	return 0;
 }
diff --git a/src/cache.h b/src/cache.h
index bf85e8e..4ddaa1e 100644
--- a/src/cache.h
+++ b/src/cache.h
@@ -39,7 +39,8 @@ cache_put(
 extern
 void
 cache_clear(
-	cache_t *cache
+	cache_t *cache,
+	uint32_t cacheid
 );
 
 extern
diff --git a/src/cyn.c b/src/cyn.c
index f853a53..6b6b17a 100644
--- a/src/cyn.c
+++ b/src/cyn.c
@@ -17,6 +17,7 @@
 
 #include <assert.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include <string.h>
@@ -52,6 +53,9 @@ static const void *lock;
 static struct callback *awaiters;
 static struct callback *observers;
 static struct agent *agents;
+static uint32_t last_changeid;
+static uint32_t last_changeid_string;
+static char changeid_string[12];
 
 static
 int
@@ -92,6 +96,17 @@ addcb(
 	return 0;
 }
 
+static
+void
+changed(
+) {
+	struct callback *c;
+
+	++last_changeid;
+	for (c = observers; c ; c = c->next)
+		c->on_change_cb(c->closure);
+}
+
 /** enter critical recoverable section */
 int
 cyn_enter(
@@ -147,7 +162,7 @@ cyn_leave(
 	bool commit
 ) {
 	int rc, rcp;
-	struct callback *c, *e, **p;
+	struct callback *e, **p;
 
 	if (!magic)
 		return -EINVAL;
@@ -164,10 +179,8 @@ cyn_leave(
 		if (rc == 0) {
 			rcp = queue_play();
 			rc = db_transaction_end(rcp == 0) ?: rcp;
-			if (rcp == 0) {
-				for (c = observers; c ; c = c->next)
-					c->on_change_cb(c->closure);
-			}
+			if (rcp == 0)
+				changed();
 		}
 	}
 	queue_clear();
@@ -472,3 +485,26 @@ cyn_agent_remove(
 	free(agent);
 	return 0;
 }
+
+void
+cyn_changeid_reset(
+) {
+	last_changeid = 1;
+}
+
+uint32_t
+cyn_changeid(
+) {
+	return last_changeid;
+}
+
+extern
+const char *
+cyn_changeid_string(
+) {
+	if (last_changeid != last_changeid_string) {
+		last_changeid_string = last_changeid;
+		snprintf(changeid_string, sizeof changeid_string, "%u", last_changeid);
+	}
+	return changeid_string;
+}
\ No newline at end of file
diff --git a/src/cyn.h b/src/cyn.h
index 2dbfa62..810026a 100644
--- a/src/cyn.h
+++ b/src/cyn.h
@@ -128,3 +128,17 @@ cyn_agent_remove(
 	const char *name
 );
 
+extern
+void
+cyn_changeid_reset(
+);
+
+extern
+uint32_t
+cyn_changeid(
+);
+
+extern
+const char *
+cyn_changeid_string(
+);
diff --git a/src/db.c b/src/db.c
index e6eb3d1..aebead2 100644
--- a/src/db.c
+++ b/src/db.c
@@ -55,7 +55,7 @@ db_open(
 
 	rc = memdb_create(&memdb);
 	if (!rc) {
-		rc = filedb_create(&filedb, directory, "CYNARA");
+		rc = filedb_create(&filedb, directory, NULL);
 		if (rc)
 			anydb_destroy(memdb);
 	}
diff --git a/src/main-cynarad.c b/src/main-cynarad.c
index 75b0169..19f0f4d 100644
--- a/src/main-cynarad.c
+++ b/src/main-cynarad.c
@@ -38,6 +38,7 @@
 
 #include "data.h"
 #include "db.h"
+#include "cyn.h"
 #include "rcyn-server.h"
 #include "rcyn-protocol.h"
 #include "dbinit.h"
@@ -303,21 +304,8 @@ int main(int ac, char **av)
 	cap_clear(caps);
 	rc = cap_set_proc(caps);
 
-	/* initialize server */
-	signal(SIGPIPE, SIG_IGN); /* avoid SIGPIPE! */
-	rc = rcyn_server_create(&server, spec_socket_admin, spec_socket_check, spec_socket_agent);
-	if (rc < 0) {
-		fprintf(stderr, "can't initialise server: %m\n");
-		return 1;
-	}
-
 	/* connection to the database */
-	rc = chdir(dbdir);
-	if (rc < 0) {
-		fprintf(stderr, "can not chroot to database directory %s: %m\n", dbdir);
-		return 1;
-	}
-	rc = db_open(".");
+	rc = db_open(dbdir);
 	if (rc < 0) {
 		fprintf(stderr, "can not open database of directory %s: %m\n", dbdir);
 		return 1;
@@ -332,6 +320,17 @@ int main(int ac, char **av)
 		}
 	}
 
+	/* reset the change ids */
+	cyn_changeid_reset();
+
+	/* initialize server */
+	signal(SIGPIPE, SIG_IGN); /* avoid SIGPIPE! */
+	rc = rcyn_server_create(&server, spec_socket_admin, spec_socket_check, spec_socket_agent);
+	if (rc < 0) {
+		fprintf(stderr, "can't initialise server: %m\n");
+		return 1;
+	}
+
 	/* ready ! */
 #if defined(WITH_SYSTEMD_ACTIVATION)
 	if (systemd)
diff --git a/src/rcyn-client.c b/src/rcyn-client.c
index baffb83..575d72c 100644
--- a/src/rcyn-client.c
+++ b/src/rcyn-client.c
@@ -256,19 +256,23 @@ int
 get_reply(
 	rcyn_t *rcyn
 ) {
+	;
 	int rc;
 
 	prot_next(rcyn->prot);
-	rc = rcyn->reply.count = prot_get(rcyn->prot, &rcyn->reply.fields);
-	if (rc <= 0)
-		return rc;
-	if (0 != strcmp(rcyn->reply.fields[0], _clear_)) {
-		if (0 != strcmp(rcyn->reply.fields[0], _item_))
-			rcyn->pending--;
-		return rc;
+	rc = prot_get(rcyn->prot, &rcyn->reply.fields);
+	if (rc > 0) {
+		if (0 == strcmp(rcyn->reply.fields[0], _clear_)) {
+			cache_clear(rcyn->cache,
+				rc > 1 ? (uint32_t)atol(rcyn->reply.fields[1]) : 0);
+			rc = 0;
+		} else {
+			if (0 != strcmp(rcyn->reply.fields[0], _item_))
+				rcyn->pending--;
+		}
 	}
-	cache_clear(rcyn->cache);
-	return rcyn->reply.count = 0;
+	rcyn->reply.count = rc;
+	return rc;
 }
 
 static
@@ -406,7 +410,6 @@ connection(
 	/* init the client */
 	rcyn->pending = 0;
 	rcyn->reply.count = -1;
-	cache_clear(rcyn->cache);
 	prot_reset(rcyn->prot);
 	rcyn->fd = socket_open(rcyn->socketspec, 0);
 	if (rcyn->fd < 0)
@@ -418,9 +421,11 @@ connection(
 		rc = wait_pending_reply(rcyn);
 		if (rc >= 0) {
 			rc = -EPROTO;
-			if (rcyn->reply.count == 2
+			if (rcyn->reply.count >= 2
 			 && 0 == strcmp(rcyn->reply.fields[0], _yes_)
 			 && 0 == strcmp(rcyn->reply.fields[1], "1")) {
+				cache_clear(rcyn->cache,
+					rcyn->reply.count > 2 ? (uint32_t)atol(rcyn->reply.fields[2]) : 0);
 				rc = async(rcyn, EPOLL_CTL_ADD, EPOLLIN);
 				if (rc >= 0)
 					return 0;
@@ -498,6 +503,13 @@ error:
 }
 
 void
+rcyn_disconnect(
+	rcyn_t *rcyn
+) {
+	disconnection(rcyn);
+}
+
+void
 rcyn_close(
 	rcyn_t *rcyn
 ) {
@@ -701,7 +713,7 @@ void
 rcyn_cache_clear(
 	rcyn_t *rcyn
 ) {
-	cache_clear(rcyn->cache);
+	cache_clear(rcyn->cache, 0);
 }
 
 int
diff --git a/src/rcyn-client.h b/src/rcyn-client.h
index a48d007..ad93689 100644
--- a/src/rcyn-client.h
+++ b/src/rcyn-client.h
@@ -52,6 +52,12 @@ rcyn_open(
 
 extern
 void
+rcyn_disconnect(
+	rcyn_t *rcyn
+);
+
+extern
+void
 rcyn_close(
 	rcyn_t *rcyn
 );
diff --git a/src/rcyn-protocol.txt b/src/rcyn-protocol.txt
index 50fd918..72789a2 100644
--- a/src/rcyn-protocol.txt
+++ b/src/rcyn-protocol.txt
@@ -4,11 +4,11 @@ protocol
 hello:
 
   c->s rcyn 1
-  s->c yes 1
+  s->c yes 1 CACHEID
 
 invalidate cache:
 
-  s->c clear
+  s->c clear CACHEID
   
 test a permission:
 
diff --git a/src/rcyn-server.c b/src/rcyn-server.c
index 4ea49b0..8f14fdb 100644
--- a/src/rcyn-server.c
+++ b/src/rcyn-server.c
@@ -299,7 +299,7 @@ onrequest(
 	if (!cli->version) {
 		if (!ckarg(args[0], _rcyn_, 0) || count != 2 || !ckarg(args[1], "1", 0))
 			goto invalid;
-		putx(cli, _yes_, "1", NULL);
+		putx(cli, _yes_, "1", cyn_changeid_string(), NULL);
 		flushw(cli);
 		cli->version = 1;
 		return;
@@ -426,7 +426,7 @@ onchange(
 	client_t *cli = closure;
 	if (cli->checked) {
 		cli->checked = false;
-		putx(cli, _clear_, NULL);
+		putx(cli, _clear_, cyn_changeid_string(), NULL);
 		flushw(cli);
 	}
 }