ust: collect many channels and start work on pipe listener

[ust.git] / libtracectl / tracectl.c

diff --git a/libtracectl/tracectl.c b/libtracectl/tracectl.c
index aca3abc207ae81ad60067778e717a7c11b3ebe92..46874d4ad4d56d15c2e6217906ebac8d898f719e 100644 (file)
--- 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();
 }