lkl: hijack: move dbg_handler out of liblkl

tools/lkl/include/lkl.h

@@ -835,18 +835,6 @@ lkl_netdev_wintap_create(const char *ifparams)
 }
 #endif
 
-
-/*
- * lkl_register_dbg_handler- register a signal handler that loads a debug lib.
- *
- * The signal handler is triggered by Ctrl-Z. It creates a new pthread which
- * call dbg_entrance().
- *
- * If you run the program from shell script, make sure you ignore SIGTSTP by
- * "trap '' TSTP" in the shell script.
- */
-void lkl_register_dbg_handler(void);
-
 /**
  * lkl_add_neighbor - add a permanent arp entry
  * @ifindex - the ifindex of the interface

tools/lkl/lib/Build

@@ -11,8 +11,6 @@ liblkl-$(LKL_HOST_CONFIG_NT) += nt-host.o
 liblkl-y += utils.o
 liblkl-y += virtio_blk.o
 liblkl-y += virtio.o
-liblkl-y += dbg.o
-liblkl-y += dbg_handler.o
 liblkl-$(LKL_HOST_CONFIG_VIRTIO_NET) += virtio_net.o
 liblkl-$(LKL_HOST_CONFIG_VIRTIO_NET_FD) += virtio_net_fd.o
 liblkl-$(LKL_HOST_CONFIG_VIRTIO_NET_FD) += virtio_net_tap.o

tools/lkl/lib/hijack/Build

@@ -2,8 +2,10 @@ liblkl-hijack-y += preload.o
 liblkl-hijack-y += hijack.o
 liblkl-hijack-y += init.o
 liblkl-hijack-y += xlate.o
+liblkl-hijack-y += dbg_handler.o
 
 liblkl-zpoline-y += zpoline.o
 liblkl-zpoline-y += hijack.o
 liblkl-zpoline-y += init.o
 liblkl-zpoline-y += xlate.o
+liblkl-zpoline-y += dbg_handler.o

tools/lkl/lib/dbg.c → tools/lkl/lib/hijack/dbg_handler.c

@@ -2,9 +2,11 @@
 #include <lkl.h>
 #include <limits.h>
 #include <string.h>
-#include <stdio.h>
 #include <stdlib.h>
+#include <stdio.h>
+#include <lkl_host.h>
 
+static int dbg_running = 0;
 static const char* PROMOTE = "$";
 #define str(x) #x
 #define xstr(s) str(s)
@@ -248,7 +250,7 @@ static void run_cmd() {
 	}
 }
 
-void dbg_entrance() {
+static void dbg_entrance() {
 	char input[MAX_BUF + 1];
 	int ret;
 	int c;
@@ -272,3 +274,37 @@ void dbg_entrance() {
 		run_cmd();
 	} while(1);
 }
+
+static void dbg_thread(void* arg) {
+	lkl_host_ops.thread_detach();
+	printf("======Enter Debug======\n");
+	dbg_entrance();
+	printf("======Exit Debug======\n");
+	dbg_running = 0;
+}
+
+void dbg_handler(int signum) {
+	/* We don't care about the possible race on dbg_running. */
+	if (dbg_running) {
+		fprintf(stderr, "A debug lib is running\n");
+		return;
+	}
+	dbg_running = 1;
+	lkl_host_ops.thread_create(&dbg_thread, NULL);
+}
+
+#ifndef __MINGW32__
+#include <signal.h>
+void lkl_register_dbg_handler() {
+	struct sigaction sa;
+	sigemptyset(&sa.sa_mask);
+	sa.sa_handler = dbg_handler;
+	if (sigaction(SIGTSTP, &sa, NULL) == -1) {
+		perror("sigaction");
+	}
+}
+#else
+void lkl_register_dbg_handler() {
+	fprintf(stderr, "lkl_register_dbg_handler is not implemented.\n");
+}
+#endif

tools/lkl/lib/hijack/init.h

@@ -7,4 +7,15 @@ extern int dual_fds[];
 void __hijack_init(void);
 void __hijack_fini(void);
 
+/*
+ * lkl_register_dbg_handler- register a signal handler that loads a debug lib.
+ *
+ * The signal handler is triggered by Ctrl-Z. It creates a new pthread which
+ * call dbg_entrance().
+ *
+ * If you run the program from shell script, make sure you ignore SIGTSTP by
+ * "trap '' TSTP" in the shell script.
+ */
+void lkl_register_dbg_handler(void);
+
 #endif /*_LKL_HIJACK_INIT_H */