X-Git-Url: http://git.lttng.org/?p=ust.git;a=blobdiff_plain;f=libustcomm%2Fustcomm.c;h=2e490b56b7f3b9bde99a3db8ade8b66f99f090da;hp=d9c795633b238ac103a4315a7045fbe5e0c5afea;hb=68ab7a5d576faa16e0da19d0f824785eac215ae9;hpb=3847c3bab100bfb6b01b5654c2429a5d0d162ff5

diff --git a/libustcomm/ustcomm.c b/libustcomm/ustcomm.c
index d9c7956..2e490b5 100644
--- a/libustcomm/ustcomm.c
+++ b/libustcomm/ustcomm.c
@@ -1,3 +1,20 @@
+/* Copyright (C) 2009  Pierre-Marc Fournier
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
 #define _GNU_SOURCE
 #include <sys/types.h>
 #include <signal.h>
@@ -5,6 +22,8 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <unistd.h>
+#include <poll.h>
+#include <sys/stat.h>
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -15,11 +34,14 @@
 #include "localerr.h"
 
 #define UNIX_PATH_MAX 108
-#define SOCK_DIR "/tmp/socks"
-#define UST_SIGNAL SIGIO
 
 #define MSG_MAX 1000
 
+/* 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];
@@ -29,143 +51,300 @@
 //	backtrace_symbols_fd(buffer, result, STDERR_FILENO);
 //}
 
-static void signal_process(pid_t pid)
+char *strdup_malloc(const char *s)
+{
+	char *retval;
+
+	if(s == NULL)
+		return NULL;
+
+	retval = (char *) malloc(strlen(s)+1);
+
+	strcpy(retval, s);
+
+	return retval;
+}
+
+static int signal_process(pid_t pid)
 {
 	int result;
 
 	result = kill(pid, UST_SIGNAL);
 	if(result == -1) {
 		PERROR("kill");
-		return;
+		return -1;
 	}
 
-	sleep(1);
+	/* FIXME: should wait in a better way */
+	//sleep(1);
+
+	return 0;
 }
 
-int send_message_path(const char *path, const char *msg, char **reply, int signalpid)
+int pid_is_online(pid_t pid) {
+	return kill(pid, UST_SIGNAL) != -1;
+}
+
+static int send_message_fd(int fd, const char *msg)
 {
-	int fd;
 	int result;
-	struct sockaddr_un addr;
 
-	result = fd = socket(PF_UNIX, SOCK_DGRAM, 0);
+	result = send(fd, msg, strlen(msg), 0);
 	if(result == -1) {
-		PERROR("socket");
+		PERROR("send");
 		return -1;
 	}
+	else if(result == 0) {
+		return 0;
+	}
 
-	addr.sun_family = AF_UNIX;
+	return 1;
+}
+
+/* Called by an app to ask the consumer daemon to connect to it. */
+
+int ustcomm_request_consumer(pid_t pid, const char *channel)
+{
+	char path[UNIX_PATH_MAX];
+	int result;
+	char *msg=NULL;
+	int retval = 0;
+	struct ustcomm_connection conn;
+	char *explicit_daemon_socket_path;
+
+	explicit_daemon_socket_path = getenv("UST_DAEMON_SOCKET");
+	if(explicit_daemon_socket_path) {
+		/* user specified explicitly a socket path */
+		result = snprintf(path, UNIX_PATH_MAX, "%s", explicit_daemon_socket_path);
+	}
+	else {
+		/* just use the default path */
+		result = snprintf(path, UNIX_PATH_MAX, "%s/ustd", SOCK_DIR);
+	}
 
-	result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s", path);
 	if(result >= UNIX_PATH_MAX) {
 		ERR("string overflow allocating socket name");
 		return -1;
 	}
 
-	if(signalpid >= 0)
-		signal_process(signalpid);
+	asprintf(&msg, "collect %d %s", pid, channel); 
 
-	result = sendto(fd, msg, strlen(msg), 0, (struct sockaddr *)&addr, sizeof(addr));
+	/* don't signal it because it's the daemon */
+	result = ustcomm_connect_path(path, &conn, -1);
 	if(result == -1) {
-		PERROR("sendto");
-		return -1;
+		WARN("ustcomm_connect_path failed");
+		retval = -1;
+		goto del_string;
 	}
 
-	if(!reply)
-		return 0;
-
-	*reply = (char *) malloc(MSG_MAX+1);
-	result = recvfrom(fd, *reply, MSG_MAX, 0, NULL, NULL);
+	result = ustcomm_send_request(&conn, msg, NULL);
 	if(result == -1) {
-		PERROR("recvfrom");
-		return -1;
+		WARN("ustcomm_send_request failed");
+		retval = -1;
+		goto disconnect;
 	}
-	
-	(*reply)[result] = '\0';
 
-	return 0;
+	disconnect:
+	ustcomm_disconnect(&conn);
+	del_string:
+	free(msg);
+
+	return retval;
 }
 
-/* pid: the pid of the trace process that must receive the msg
-   msg: pointer to a null-terminated message to send
-   reply: location where to put the null-terminated string of the reply;
-	  it must be free'd after usage
+/* returns 1 to indicate a message was received
+ * returns 0 to indicate no message was received (cannot happen)
+ * returns -1 to indicate an error
  */
 
-int send_message(pid_t pid, const char *msg, char **reply)
+static int recv_message_fd(int fd, char **msg, struct ustcomm_source *src)
 {
 	int result;
-	char path[UNIX_PATH_MAX];
 
-	result = snprintf(path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
-	if(result >= UNIX_PATH_MAX) {
-		fprintf(stderr, "string overflow allocating socket name");
+	*msg = (char *) malloc(MSG_MAX+1);
+
+	result = recv(fd, *msg, MSG_MAX, 0);
+	if(result == -1) {
+		PERROR("recv");
 		return -1;
 	}
 
-	send_message_path(path, msg, reply, pid);
+	(*msg)[result] = '\0';
+	
+	DBG("ustcomm_app_recv_message: result is %d, message is %s", result, (*msg));
 
-	return 0;
-}
+	if(src)
+		src->fd = fd;
 
-/* Called by an app to ask the consumer daemon to connect to it. */
+	return 1;
+}
 
-int ustcomm_request_consumer(pid_t pid, const char *channel)
+int ustcomm_send_reply(struct ustcomm_server *server, char *msg, struct ustcomm_source *src)
 {
-	char path[UNIX_PATH_MAX];
 	int result;
-	char *msg;
 
-	result = snprintf(path, UNIX_PATH_MAX, "%s/ustd", SOCK_DIR);
-	if(result >= UNIX_PATH_MAX) {
-		fprintf(stderr, "string overflow allocating socket name");
+	result = send_message_fd(src->fd, msg);
+	if(result < 0) {
+		ERR("error in send_message_fd");
 		return -1;
 	}
 
-	asprintf(&msg, "collect %d %s", pid, channel); 
+	return 0;
+} 
 
-	send_message_path(path, msg, NULL, -1);
-	free(msg);
+/* Called after a fork. */
+
+int ustcomm_close_all_connections(struct ustcomm_server *server)
+{
+	struct ustcomm_connection *conn;
+	struct ustcomm_connection *deletable_conn = NULL;
+
+	list_for_each_entry(conn, &server->connections, list) {
+		free(deletable_conn);
+		deletable_conn = conn;
+		close(conn->fd);
+		list_del(&conn->list);
+	}
 
 	return 0;
 }
 
-static int recv_message_fd(int fd, char **msg)
+/* @timeout: max blocking time in milliseconds, -1 means infinity
+ *
+ * returns 1 to indicate a message was received
+ * returns 0 to indicate no message was received
+ * returns -1 to indicate an error
+ */
+
+int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustcomm_source *src, int timeout)
 {
+	struct pollfd *fds;
+	struct ustcomm_connection *conn;
 	int result;
-
-	*msg = (char *) malloc(MSG_MAX+1);
-	result = recvfrom(fd, *msg, MSG_MAX, 0, NULL, NULL);
-	if(result == -1) {
-		PERROR("recvfrom");
-		return -1;
+	int retval;
+
+	for(;;) {
+		int idx = 0;
+		int n_fds = 1;
+
+		list_for_each_entry(conn, &server->connections, list) {
+			n_fds++;
+		}
+
+		fds = (struct pollfd *) malloc(n_fds * sizeof(struct pollfd));
+		if(fds == NULL) {
+			ERR("malloc returned NULL");
+			return -1;
+		}
+
+		/* special idx 0 is for listening socket */
+		fds[idx].fd = server->listen_fd;
+		fds[idx].events = POLLIN;
+		idx++;
+
+		list_for_each_entry(conn, &server->connections, list) {
+			fds[idx].fd = conn->fd;
+			fds[idx].events = POLLIN;
+			idx++;
+		}
+
+		while((result = poll(fds, n_fds, timeout)) == -1 && errno == EINTR)
+			/* nothing */;
+		if(result == -1) {
+			PERROR("poll");
+			return -1;
+		}
+
+		if(result == 0)
+			return 0;
+
+		if(fds[0].revents) {
+			struct ustcomm_connection *newconn;
+			int newfd;
+
+			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;
+			}
+
+			newconn->fd = newfd;
+
+			list_add(&newconn->list, &server->connections);
+		}
+
+		for(idx=1; idx<n_fds; idx++) {
+			if(fds[idx].revents) {
+				retval = recv_message_fd(fds[idx].fd, msg, src);
+				if(**msg == 0) {
+					/* connection finished */
+					close(fds[idx].fd);
+
+					list_for_each_entry(conn, &server->connections, list) {
+						if(conn->fd == fds[idx].fd) {
+							list_del(&conn->list);
+							break;
+						}
+					}
+				}
+				else {
+					goto free_fds_return;
+				}
+			}
+		}
+
+		free(fds);
 	}
 
-	(*msg)[result] = '\0';
-	
-	DBG("ustcomm_app_recv_message: result is %d, message is %s", result, (*msg));
+free_fds_return:
+	free(fds);
+	return retval;
+}
 
-	return 0;
+int ustcomm_ustd_recv_message(struct ustcomm_ustd *ustd, char **msg, struct ustcomm_source *src, int timeout)
+{
+	return ustcomm_recv_message(&ustd->server, msg, src, timeout);
 }
 
-int ustcomm_ustd_recv_message(struct ustcomm_ustd *ustd, char **msg)
+int ustcomm_app_recv_message(struct ustcomm_app *app, char **msg, struct ustcomm_source *src, int timeout)
 {
-	return recv_message_fd(ustd->fd, msg);
+	return ustcomm_recv_message(&app->server, msg, src, timeout);
 }
 
-int ustcomm_app_recv_message(struct ustcomm_app *app, char **msg)
+/* This removes src from the list of active connections of app.
+ */
+
+int ustcomm_app_detach_client(struct ustcomm_app *app, struct ustcomm_source *src)
 {
-	return recv_message_fd(app->fd, msg);
+	struct ustcomm_server *server = (struct ustcomm_server *)app;
+	struct ustcomm_connection *conn;
+
+	list_for_each_entry(conn, &server->connections, list) {
+		if(conn->fd == src->fd) {
+			list_del(&conn->list);
+			goto found;
+		}
+	}
+
+	return -1;
+found:
+	return src->fd;
 }
 
-static int init_named_socket(char *name, char **path_out)
+static int init_named_socket(const char *name, char **path_out)
 {
 	int result;
 	int fd;
 
 	struct sockaddr_un addr;
 	
-	result = fd = socket(PF_UNIX, SOCK_DGRAM, 0);
+	result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 	if(result == -1) {
 		PERROR("socket");
 		return -1;
@@ -176,15 +355,31 @@ static int init_named_socket(char *name, char **path_out)
 	strncpy(addr.sun_path, name, UNIX_PATH_MAX);
 	addr.sun_path[UNIX_PATH_MAX-1] = '\0';
 
+	result = access(name, F_OK);
+	if(result == 0) {
+		/* file exists */
+		result = unlink(name);
+		if(result == -1) {
+			PERROR("unlink of socket file");
+			goto close_sock;
+		}
+		WARN("socket already exists; overwriting");
+	}
+
 	result = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
 	if(result == -1) {
 		PERROR("bind");
 		goto close_sock;
 	}
 
+	result = listen(fd, 1);
+	if(result == -1) {
+		PERROR("listen");
+		goto close_sock;
+	}
+
 	if(path_out) {
-		*path_out = "";
-		*path_out = strdupa(addr.sun_path);
+		*path_out = strdup(addr.sun_path);
 	}
 
 	return fd;
@@ -195,6 +390,109 @@ static int init_named_socket(char *name, char **path_out)
 	return -1;
 }
 
+/*
+ * Return value:
+ *   0: Success, but no reply because recv() returned 0
+ *   1: Success
+ *   -1: Error
+ *
+ * On error, the error message is printed, except on
+ * ECONNRESET, which is normal when the application dies.
+ */
+
+int ustcomm_send_request(struct ustcomm_connection *conn, const char *req, char **reply)
+{
+	int result;
+
+	result = send(conn->fd, req, strlen(req), MSG_NOSIGNAL);
+	if(result == -1) {
+		if(errno != EPIPE)
+			PERROR("send");
+		return -1;
+	}
+
+	if(!reply)
+		return 1;
+
+	*reply = (char *) malloc(MSG_MAX+1);
+	result = recv(conn->fd, *reply, MSG_MAX, 0);
+	if(result == -1) {
+		if(errno != ECONNRESET)
+			PERROR("recv");
+		return -1;
+	}
+	else if(result == 0) {
+		return 0;
+	}
+	
+	(*reply)[result] = '\0';
+
+	return 1;
+}
+
+int ustcomm_connect_path(const char *path, struct ustcomm_connection *conn, pid_t signalpid)
+{
+	int fd;
+	int result;
+	struct sockaddr_un addr;
+
+	result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
+	if(result == -1) {
+		PERROR("socket");
+		return -1;
+	}
+
+	addr.sun_family = AF_UNIX;
+
+	result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s", path);
+	if(result >= UNIX_PATH_MAX) {
+		ERR("string overflow allocating socket name");
+		return -1;
+	}
+
+	if(signalpid >= 0) {
+		result = signal_process(signalpid);
+		if(result == -1) {
+			ERR("could not signal process");
+			return -1;
+		}
+	}
+
+	result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
+	if(result == -1) {
+		PERROR("connect");
+		return -1;
+	}
+
+	conn->fd = fd;
+
+	return 0;
+}
+
+int ustcomm_disconnect(struct ustcomm_connection *conn)
+{
+	return close(conn->fd);
+}
+
+int ustcomm_connect_app(pid_t pid, struct ustcomm_connection *conn)
+{
+	int result;
+	char path[UNIX_PATH_MAX];
+
+
+	result = snprintf(path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
+	if(result >= UNIX_PATH_MAX) {
+		ERR("string overflow allocating socket name");
+		return -1;
+	}
+
+	return ustcomm_connect_path(path, conn, pid);
+}
+
+/* Called by an application to initialize its server so daemons can
+ * connect to it.
+ */
+
 int ustcomm_init_app(pid_t pid, struct ustcomm_app *handle)
 {
 	int result;
@@ -206,12 +504,15 @@ int ustcomm_init_app(pid_t pid, struct ustcomm_app *handle)
 		return -1;
 	}
 
-	handle->fd = init_named_socket(name, &(handle->socketpath));
-	if(handle->fd < 0) {
+	handle->server.listen_fd = init_named_socket(name, &(handle->server.socketpath));
+	if(handle->server.listen_fd < 0) {
+		ERR("Error initializing named socket (%s). Check that directory exists and that it is writable.", name);
 		goto free_name;
 	}
 	free(name);
 
+	INIT_LIST_HEAD(&handle->server.connections);
+
 	return 0;
 
 free_name:
@@ -219,21 +520,143 @@ free_name:
 	return -1;
 }
 
-int ustcomm_init_ustd(struct ustcomm_ustd *handle)
+/* Used by the daemon to initialize its server so applications
+ * can connect to it.
+ */
+
+int ustcomm_init_ustd(struct ustcomm_ustd *handle, const char *sock_path)
 {
-	int result;
 	char *name;
+	int retval = 0;
 
-	result = asprintf(&name, "%s/%s", SOCK_DIR, "ustd");
-	if(result >= UNIX_PATH_MAX) {
-		ERR("string overflow allocating socket name");
-		return -1;
+	if(sock_path) {
+		asprintf(&name, "%s", sock_path);
+	}
+	else {
+		asprintf(&name, "%s/%s", SOCK_DIR, "ustd");
+	}
+
+	handle->server.listen_fd = init_named_socket(name, &handle->server.socketpath);
+	if(handle->server.listen_fd < 0) {
+		ERR("error initializing named socket at %s", name);
+		retval = -1;
+		goto free_name;
 	}
 
-	handle->fd = init_named_socket(name, &handle->socketpath);
-	if(handle->fd < 0)
-		return handle->fd;
+	INIT_LIST_HEAD(&handle->server.connections);
+
+free_name:
 	free(name);
 
-	return 0;
+	return retval;
+}
+
+void ustcomm_fini_app(struct ustcomm_app *handle)
+{
+	int result;
+	struct stat st;
+
+	/* Destroy socket */
+	result = stat(handle->server.socketpath, &st);
+	if(result == -1) {
+		PERROR("stat (%s)", handle->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;
+	}
+
+	result = unlink(handle->server.socketpath);
+	if(result == -1) {
+		PERROR("unlink");
+	}
+}
+
+static char *find_tok(char *str)
+{
+	while(*str == ' ') {
+		str++;
+
+		if(*str == 0)
+			return NULL;
+	}
+
+	return str;
+}
+
+static char *find_sep(char *str)
+{
+	while(*str != ' ') {
+		str++;
+
+		if(*str == 0)
+			break;
+	}
+
+	return str;
+}
+
+int nth_token_is(char *str, char *token, int tok_no)
+{
+	int i;
+	char *start;
+	char *end;
+
+	for(i=0; i<=tok_no; i++) {
+		str = find_tok(str);
+		if(str == NULL)
+			return -1;
+
+		start = str;
+
+		str = find_sep(str);
+		if(str == NULL)
+			return -1;
+
+		end = str;
+	}
+
+	if(end-start != strlen(token))
+		return 0;
+
+	if(strncmp(start, token, end-start))
+		return 0;
+
+	return 1;
+}
+
+char *nth_token(char *str, int tok_no)
+{
+	static char *retval = NULL;
+	int i;
+	char *start;
+	char *end;
+
+	for(i=0; i<=tok_no; i++) {
+		str = find_tok(str);
+		if(str == NULL)
+			return NULL;
+
+		start = str;
+
+		str = find_sep(str);
+		if(str == NULL)
+			return NULL;
+
+		end = str;
+	}
+
+	if(retval) {
+		free(retval);
+		retval = NULL;
+	}
+
+	asprintf(&retval, "%.*s", (int)(end-start), start);
+
+	return retval;
 }
+