X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libtracectl%2Ftracectl.c;h=46874d4ad4d56d15c2e6217906ebac8d898f719e;hb=98963de4a2dfae12d8aafa0f9a6d97cf4a44e12d;hp=aca3abc207ae81ad60067778e717a7c11b3ebe92;hpb=9c67dc50afb2eaa1c3966ee73fac3ce55935556c;p=ust.git

diff --git a/libtracectl/tracectl.c b/libtracectl/tracectl.c
index aca3abc..46874d4 100644
--- a/libtracectl/tracectl.c
+++ b/libtracectl/tracectl.c
@@ -4,6 +4,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include <sched.h>
 #define UNIX_PATH_MAX 108
 
 //#define SOCKETDIR "/var/run/ust/socks"
@@ -16,14 +17,32 @@
 #define ERR(fmt, args...) fprintf(stderr, "usertrace: ERROR: " fmt "\n", ## args)
 #define PERROR(call) perror("usertrace: ERROR: " call)
 
+#define MAX_MSG_SIZE (100)
+#define MSG_NOTIF 1
+#define MSG_REGISTER_NOTIF 2
+
 struct tracecmd { /* no padding */
 	uint32_t size;
 	uint16_t command;
 };
 
+//struct listener_arg {
+//	int pipe_fd;
+//};
+
+struct trctl_msg {
+	/* size: the size of all the fields except size itself */
+	uint32_t size;
+	uint16_t type;
+	/* Only the necessary part of the payload is transferred. It
+         * may even be none of it.
+         */
+	char payload[94];
+};
 
 pid_t mypid;
 char mysocketfile[UNIX_PATH_MAX] = "";
+int pfd = -1;
 
 void do_command(struct tracecmd *cmd)
 {
@@ -33,6 +52,94 @@ void receive_commands()
 {
 }
 
+int fd_notif = -1;
+void notif_cb(void)
+{
+	int result;
+	struct trctl_msg msg;
+
+	/* FIXME: fd_notif should probably be protected by a spinlock */
+
+	if(fd_notif == -1)
+		return;
+
+	msg.type = MSG_NOTIF;
+	msg.size = sizeof(msg.type);
+
+	/* FIXME: don't block here */
+	result = write(fd_notif, &msg, msg.size+sizeof(msg.size));
+	if(result == -1) {
+		PERROR("write");
+		return;
+	}
+}
+
+int listener_main(void *p)
+{
+	int result;
+
+	/* Allowing only 1 connection for now. */
+	result = listen(pfd, 1);
+	if(result == -1) {
+		PERROR("listen");
+		return 1;
+	}
+
+	for(;;) {
+
+		uint32_t size;
+		int fd;
+		struct sockaddr_un addr;
+		socklen_t addrlen = sizeof(addr);
+
+		result = fd = accept(pfd, (struct sockaddr *)&addr, &addrlen);
+		if(result == -1) {
+			PERROR("accept");
+			continue;
+		}
+
+		for(;;) {
+			struct trctl_msg msg;
+			unsigned char dontclose=0;
+
+			result = read(fd, &msg.size, sizeof(msg.size));
+			if(result == -1) {
+				PERROR("read");
+				continue;
+			}
+
+			if(size > MAX_MSG_SIZE) {
+				ERR("trctl message too big");
+				break;
+			}
+
+			result = read(fd, &msg.type, sizeof(msg.type));
+			if(result == -1) {
+				PERROR("read");
+				continue;
+			}
+
+			switch(msg.type) {
+				case MSG_REGISTER_NOTIF:
+					/* TODO: put it in notif mode */
+					goto next_conn;
+			};
+		}
+		next_conn:;
+	}
+}
+
+void create_listener(void)
+{
+	int result;
+	static char listener_stack[16384];
+
+	result = clone(listener_main, listener_stack+sizeof(listener_stack)-1, CLONE_FS | CLONE_FILES | CLONE_VM, NULL);
+	if(result == -1) {
+		perror("clone");
+	}
+}
+
 /* The signal handler itself. */
 
 void sighandler(int sig)
@@ -43,12 +150,12 @@ void sighandler(int sig)
 
 /* Called by the app signal handler to chain it to us. */
 
-void chain_signal()
+void chain_signal(void)
 {
 	sighandler(USTSIGNAL);
 }
 
-int init_socket()
+static int init_socket(void)
 {
 	int result;
 	int fd;
@@ -80,13 +187,16 @@ int init_socket()
 
 	strcpy(mysocketfile, addr.sun_path);
 
+	pfd = fd;
+	return 0;
+
 	close_sock:
 	close(fd);
 
 	return -1;
 }
 
-void destroy_socket()
+static void destroy_socket(void)
 {
 	int result;
 
@@ -99,7 +209,7 @@ void destroy_socket()
 	}
 }
 
-int init_signal_handler(void)
+static int init_signal_handler(void)
 {
 	/* Attempt to handler SIGIO. If the main program wants to
 	 * handle it, fine, it'll override us. They it'll have to
@@ -130,15 +240,25 @@ int init_signal_handler(void)
 	return 0;
 }
 
-void __attribute__((constructor)) init()
+static void __attribute__((constructor)) init()
 {
 	int result;
 
 	mypid = getpid();
 
-	/* if using instead seperate thread, then should create thread */
-	result = init_signal_handler();
+	/* Must create socket before signal handler to prevent races
+         * on pfd variable.
+         */
 	result = init_socket();
+	if(result == -1) {
+		ERR("init_socket error");
+		return;
+	}
+	result = init_signal_handler();
+	if(result == -1) {
+		ERR("init_signal_handler error");
+		return;
+	}
 
 	return;
 
@@ -149,7 +269,7 @@ void __attribute__((constructor)) init()
 /* This is only called if we terminate normally, not with an unhandled signal,
  * so we cannot rely on it. */
 
-void __attribute__((destructor)) fini()
+static void __attribute__((destructor)) fini()
 {
 	destroy_socket();
 }