#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"
#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)
{
{
}
+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)
/* 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;
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;
}
}
-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
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;
/* 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();
}