X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=libustcomm%2Fustcomm.c;h=d537eebf8a7164b0acf02c415889e6fb632e62fb;hb=93e5ce29599beb7b32858b3074b8433dfffdab34;hp=ba98098b2d3a76387d57a40d3f811f16a4b1e0c8;hpb=c555b1339182be95b625dc4c1d6ac7217d3f471b;p=ust.git

diff --git a/libustcomm/ustcomm.c b/libustcomm/ustcomm.c
index ba98098..d537eeb 100644
--- a/libustcomm/ustcomm.c
+++ b/libustcomm/ustcomm.c
@@ -15,6 +15,8 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
+/* API used by UST components to communicate with each other via sockets. */
+
 #define _GNU_SOURCE
 #include <sys/types.h>
 #include <signal.h>
@@ -33,25 +35,10 @@
 #include "ustcomm.h"
 #include "usterr.h"
 #include "share.h"
+#include "multipoll.h"
 
 #define UNIX_PATH_MAX 108
 
-#define MSG_MAX 10000
-
-/* FIXME: ustcomm blocks on message sending, which might be problematic in
- * some cases. Fix the poll() usage so sends are buffered until they don't
- * block.
- */
-
-//static void bt(void)
-//{
-//	void *buffer[100];
-//	int result;
-//
-//	result = backtrace(&buffer, 100);
-//	backtrace_symbols_fd(buffer, result, STDERR_FILENO);
-//}
-
 static int mkdir_p(const char *path, mode_t mode)
 {
 	const char *path_p;
@@ -101,23 +88,16 @@ static int mkdir_p(const char *path, mode_t mode)
 	return retval;
 }
 
-char *strdup_malloc(const char *s)
+static int signal_process(pid_t pid)
 {
-	char *retval;
-
-	if(s == NULL)
-		return NULL;
-
-	retval = (char *) malloc(strlen(s)+1);
-
-	strcpy(retval, s);
-
-	return retval;
+	return 0;
 }
 
-static int signal_process(pid_t pid)
+void ustcomm_init_connection(struct ustcomm_connection *conn)
 {
-	return 0;
+	conn->recv_buf = NULL;
+	conn->recv_buf_size = 0;
+	conn->recv_buf_alloc = 0;
 }
 
 int pid_is_online(pid_t pid) {
@@ -210,65 +190,92 @@ int ustcomm_request_consumer(pid_t pid, const char *channel)
  * returns -1 to indicate an error
  */
 
-#define RECV_INCREMENT 1
+#define RECV_INCREMENT 1000
 #define RECV_INITIAL_BUF_SIZE 10
 
-static int recv_message_fd(int fd, char **msg)
+static int recv_message_fd(int fd, char **recv_buf, int *recv_buf_size, int *recv_buf_alloc, char **msg)
 {
 	int result;
-	int buf_alloc_size = 0;
-	char *buf = NULL;
-	int buf_used_size = 0;
 
-	buf = malloc(RECV_INITIAL_BUF_SIZE);
-	buf_alloc_size = RECV_INITIAL_BUF_SIZE;
+	/* 1. Check if there is a message in the buf */
+	/* 2. If not, do:
+           2.1 receive chunk and put it in buffer
+	   2.2 process full message if there is one
+	   -- while no message arrived
+	*/
 
 	for(;;) {
-		if(buf_used_size + RECV_INCREMENT > buf_alloc_size) {
-			char *new_buf;
-			buf_alloc_size *= 2;
-			new_buf = (char *) realloc(buf, buf_alloc_size);
-			if(new_buf == NULL) {
-				ERR("realloc returned NULL");
-				free(buf);
-				return -1;
+		int i;
+		int nulfound = 0;
+
+		/* Search for full message in buffer */
+		for(i=0; i<*recv_buf_size; i++) {
+			if((*recv_buf)[i] == '\0') {
+				nulfound = 1;
+				break;
 			}
-			buf = new_buf;
 		}
 
-		/* FIXME: this is really inefficient; but with count>1 we would
-		 * need a buffering mechanism */
-		result = recv(fd, buf+buf_used_size, RECV_INCREMENT, 0);
+		/* Process found message */
+		if(nulfound == 1) {
+			char *newbuf;
+
+			if(i == 0) {
+				/* problem */
+				WARN("received empty message");
+			}
+			*msg = strndup(*recv_buf, i);
+
+			/* Remove processed message from buffer */
+			newbuf = (char *) malloc(*recv_buf_size - (i+1));
+			memcpy(newbuf, *recv_buf + (i+1), *recv_buf_size - (i+1));
+			free(*recv_buf);
+			*recv_buf = newbuf;
+			*recv_buf_size -= (i+1);
+			*recv_buf_alloc -= (i+1);
+
+			return 1;
+		}
+
+		/* Receive a chunk from the fd */
+		if(*recv_buf_alloc - *recv_buf_size < RECV_INCREMENT) {
+			*recv_buf_alloc += RECV_INCREMENT - (*recv_buf_alloc - *recv_buf_size);
+			*recv_buf = (char *) realloc(*recv_buf, *recv_buf_alloc);
+		}
+
+		result = recv(fd, *recv_buf+*recv_buf_size, RECV_INCREMENT, 0);
 		if(result == -1) {
-			free(buf);
-			if(errno != ECONNRESET)
+			if(errno == ECONNRESET) {
+				*recv_buf_size = 0;
+				return 0;
+			}
+			else if(errno == EINTR) {
+				return -1;
+			}
+			else {
 				PERROR("recv");
-			return -1;
+				return -1;
+			}
 		}
 		if(result == 0) {
-			if(buf_used_size)
-				goto ret;
-			else {
-				free(buf);
-				return 0;
-			}
+			return 0;
 		}
+		*recv_buf_size += result;
 
-		buf_used_size += result;
-
-		if(buf[buf_used_size-1] == 0) {
-			goto ret;
-		}
+		/* Go back to the beginning to check if there is a full message in the buffer */
 	}
 
-ret:
-	*msg = buf;
-	DBG("received message \"%s\"", buf);
+	DBG("received message \"%s\"", *recv_buf);
 
 	return 1;
 
 }
 
+static int recv_message_conn(struct ustcomm_connection *conn, char **msg)
+{
+	return recv_message_fd(conn->fd, &conn->recv_buf, &conn->recv_buf_size, &conn->recv_buf_alloc, msg);
+}
+
 int ustcomm_send_reply(struct ustcomm_server *server, char *msg, struct ustcomm_source *src)
 {
 	int result;
@@ -292,7 +299,7 @@ int ustcomm_close_all_connections(struct ustcomm_server *server)
 	list_for_each_entry(conn, &server->connections, list) {
 		free(deletable_conn);
 		deletable_conn = conn;
-		close(conn->fd);
+		ustcomm_close_app(conn);
 		list_del(&conn->list);
 	}
 
@@ -309,6 +316,7 @@ int ustcomm_close_all_connections(struct ustcomm_server *server)
 int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustcomm_source *src, int timeout)
 {
 	struct pollfd *fds;
+	struct ustcomm_connection **conn_table;
 	struct ustcomm_connection *conn;
 	int result;
 	int retval;
@@ -327,6 +335,13 @@ int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustco
 			return -1;
 		}
 
+		conn_table = (struct ustcomm_connection **) malloc(n_fds * sizeof(struct ustcomm_connection *));
+		if(conn_table == NULL) {
+			ERR("malloc returned NULL");
+			retval = -1;
+			goto free_fds_return;
+		}
+
 		/* special idx 0 is for listening socket */
 		fds[idx].fd = server->listen_fd;
 		fds[idx].events = POLLIN;
@@ -335,18 +350,25 @@ int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustco
 		list_for_each_entry(conn, &server->connections, list) {
 			fds[idx].fd = conn->fd;
 			fds[idx].events = POLLIN;
+			conn_table[idx] = conn;
 			idx++;
 		}
 
-		while((result = poll(fds, n_fds, timeout)) == -1 && errno == EINTR)
-			/* nothing */;
-		if(result == -1) {
+		result = poll(fds, n_fds, timeout);
+		if(result == -1 && errno == EINTR) {
+			/* That's ok. ustd receives signals to notify it must shutdown. */
+			retval = -1;
+			goto free_conn_table_return;
+		}
+		else if(result == -1) {
 			PERROR("poll");
-			return -1;
+			retval = -1;
+			goto free_conn_table_return;
+		}
+		else if(result == 0) {
+			retval = 0;
+			goto free_conn_table_return;
 		}
-
-		if(result == 0)
-			return 0;
 
 		if(fds[0].revents) {
 			struct ustcomm_connection *newconn;
@@ -355,7 +377,8 @@ int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustco
 			result = newfd = accept(server->listen_fd, NULL, NULL);
 			if(result == -1) {
 				PERROR("accept");
-				return -1;
+				retval = -1;
+				goto free_conn_table_return;
 			}
 
 			newconn = (struct ustcomm_connection *) malloc(sizeof(struct ustcomm_connection));
@@ -364,6 +387,7 @@ int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustco
 				return -1;
 			}
 
+			ustcomm_init_connection(newconn);
 			newconn->fd = newfd;
 
 			list_add(&newconn->list, &server->connections);
@@ -371,30 +395,33 @@ int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustco
 
 		for(idx=1; idx<n_fds; idx++) {
 			if(fds[idx].revents) {
-				retval = recv_message_fd(fds[idx].fd, msg);
+				retval = recv_message_conn(conn_table[idx], msg);
 				if(src)
 					src->fd = fds[idx].fd;
 
 				if(retval == 0) {
 					/* connection finished */
-					close(fds[idx].fd);
-
 					list_for_each_entry(conn, &server->connections, list) {
 						if(conn->fd == fds[idx].fd) {
+							ustcomm_close_app(conn);
 							list_del(&conn->list);
+							free(conn);
 							break;
 						}
 					}
 				}
 				else {
-					goto free_fds_return;
+					goto free_conn_table_return;
 				}
 			}
 		}
 
 		free(fds);
+		free(conn_table);
 	}
 
+free_conn_table_return:
+	free(conn_table);
 free_fds_return:
 	free(fds);
 	return retval;
@@ -456,7 +483,7 @@ static int init_named_socket(const char *name, char **path_out)
 			PERROR("unlink of socket file");
 			goto close_sock;
 		}
-		WARN("socket already exists; overwriting");
+		DBG("socket already exists; overwriting");
 	}
 
 	result = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
@@ -505,7 +532,7 @@ int ustcomm_send_request(struct ustcomm_connection *conn, const char *req, char
 	if(!reply)
 		return 1;
 
-	result = recv_message_fd(conn->fd, reply);
+	result = recv_message_conn(conn, reply);
 	if(result == -1) {
 		return -1;
 	}
@@ -516,12 +543,19 @@ int ustcomm_send_request(struct ustcomm_connection *conn, const char *req, char
 	return 1;
 }
 
+/* Return value:
+ *  0: success
+ * -1: error
+ */
+
 int ustcomm_connect_path(const char *path, struct ustcomm_connection *conn, pid_t signalpid)
 {
 	int fd;
 	int result;
 	struct sockaddr_un addr;
 
+	ustcomm_init_connection(conn);
+
 	result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 	if(result == -1) {
 		PERROR("socket");
@@ -560,6 +594,13 @@ int ustcomm_disconnect(struct ustcomm_connection *conn)
 	return close(conn->fd);
 }
 
+/* Open a connection to a traceable app.
+ *
+ * Return value:
+ *  0: success
+ * -1: error
+ */
+
 int ustcomm_connect_app(pid_t pid, struct ustcomm_connection *conn)
 {
 	int result;
@@ -575,6 +616,19 @@ int ustcomm_connect_app(pid_t pid, struct ustcomm_connection *conn)
 	return ustcomm_connect_path(path, conn, pid);
 }
 
+/* Close a connection to a traceable app. It frees the
+ * resources. It however does not free the
+ * ustcomm_connection itself.
+ */
+
+int ustcomm_close_app(struct ustcomm_connection *conn)
+{
+	close(conn->fd);
+	free(conn->recv_buf);
+
+	return 0;
+}
+
 static int ensure_dir_exists(const char *dir)
 {
 	struct stat st;
@@ -678,31 +732,55 @@ free_name:
 	return retval;
 }
 
-void ustcomm_fini_app(struct ustcomm_app *handle)
+static void ustcomm_fini_server(struct ustcomm_server *server, int keep_socket_file)
 {
 	int result;
 	struct stat st;
 
-	/* Destroy socket */
-	result = stat(handle->server.socketpath, &st);
-	if(result == -1) {
-		PERROR("stat (%s)", handle->server.socketpath);
-		return;
-	}
+	if(!keep_socket_file) {
+		/* Destroy socket */
+		result = stat(server->socketpath, &st);
+		if(result == -1) {
+			PERROR("stat (%s)", server->socketpath);
+			return;
+		}
 
-	/* Paranoid check before deleting. */
-	result = S_ISSOCK(st.st_mode);
-	if(!result) {
-		ERR("The socket we are about to delete is not a socket.");
-		return;
+		/* Paranoid check before deleting. */
+		result = S_ISSOCK(st.st_mode);
+		if(!result) {
+			ERR("The socket we are about to delete is not a socket.");
+			return;
+		}
+
+		result = unlink(server->socketpath);
+		if(result == -1) {
+			PERROR("unlink");
+		}
 	}
 
-	result = unlink(handle->server.socketpath);
+	free(server->socketpath);
+
+	result = close(server->listen_fd);
 	if(result == -1) {
-		PERROR("unlink");
+		PERROR("close");
+		return;
 	}
 }
 
+/* Free a traceable application server */
+
+void ustcomm_fini_app(struct ustcomm_app *handle, int keep_socket_file)
+{
+	ustcomm_fini_server(&handle->server, keep_socket_file);
+}
+
+/* Free a ustd server */
+
+void ustcomm_fini_ustd(struct ustcomm_ustd *handle)
+{
+	ustcomm_fini_server(&handle->server, 0);
+}
+
 static const char *find_tok(const char *str)
 {
 	while(*str == ' ') {
@@ -787,3 +865,88 @@ char *nth_token(const char *str, int tok_no)
 	return retval;
 }
 
+/* Callback from multipoll.
+ * Receive a new connection on the listening socket.
+ */
+
+static int process_mp_incoming_conn(void *priv, int fd, short events)
+{
+	struct ustcomm_connection *newconn;
+	struct ustcomm_server *server = (struct ustcomm_server *) priv;
+	int newfd;
+	int result;
+
+	result = newfd = accept(server->listen_fd, NULL, NULL);
+	if(result == -1) {
+		PERROR("accept");
+		return -1;
+	}
+
+	newconn = (struct ustcomm_connection *) malloc(sizeof(struct ustcomm_connection));
+	if(newconn == NULL) {
+		ERR("malloc returned NULL");
+		return -1;
+	}
+
+	ustcomm_init_connection(newconn);
+	newconn->fd = newfd;
+
+	list_add(&newconn->list, &server->connections);
+
+	return 0;
+}
+
+/* Callback from multipoll.
+ * Receive a message on an existing connection.
+ */
+
+static int process_mp_conn_msg(void *priv, int fd, short revents)
+{
+	struct ustcomm_multipoll_conn_info *mpinfo = (struct ustcomm_multipoll_conn_info *) priv;
+	int result;
+	char *msg;
+	struct ustcomm_source src;
+
+	if(revents) {
+		src.fd = fd;
+
+		result = recv_message_conn(mpinfo->conn, &msg);
+		if(result == -1) {
+			ERR("error in recv_message_conn");
+		}
+
+		else if(result == 0) {
+			/* connection finished */
+			ustcomm_close_app(mpinfo->conn);
+			list_del(&mpinfo->conn->list);
+			free(mpinfo->conn);
+		}
+		else {
+			mpinfo->cb(msg, &src);
+			free(msg);
+		}
+	}
+
+	return 0;
+}
+
+int free_ustcomm_client_poll(void *data)
+{
+	free(data);
+	return 0;
+}
+
+void ustcomm_mp_add_app_clients(struct mpentries *ent, struct ustcomm_app *app, int (*cb)(char *recvbuf, struct ustcomm_source *src))
+{
+	struct ustcomm_connection *conn;
+
+	/* add listener socket */
+	multipoll_add(ent, app->server.listen_fd, POLLIN, process_mp_incoming_conn, &app->server, NULL);
+
+	list_for_each_entry(conn, &app->server.connections, list) {
+		struct ustcomm_multipoll_conn_info *mpinfo = (struct ustcomm_multipoll_conn_info *) malloc(sizeof(struct ustcomm_multipoll_conn_info));
+		mpinfo->conn = conn;
+		mpinfo->cb = cb;
+		multipoll_add(ent, conn->fd, POLLIN, process_mp_conn_msg, mpinfo, free_ustcomm_client_poll);
+	}
+}