Add clone arguments to callback hooks

include/libsyscall_intercept_hook_point.h

@@ -57,8 +57,12 @@ extern int (*intercept_hook_point)(long syscall_number,
 			long arg4, long arg5,
 			long *result);
 
-extern void (*intercept_hook_point_clone_child)(void);
-extern void (*intercept_hook_point_clone_parent)(long pid);
+extern void (*intercept_hook_point_clone_child)(
+		unsigned long clone_flags, unsigned long newsp,
+		void *parent_tid, void *child_tid, unsigned tid);
+extern void (*intercept_hook_point_clone_parent)(
+		long *pid, unsigned long clone_flags, unsigned long newsp,
+		void *parent_tid, void *child_tid, unsigned tid);
 
 /*
  * syscall_no_intercept - syscall without interception

src/intercept.c

@@ -67,9 +67,13 @@ int (*intercept_hook_point)(long syscall_number,
 			long *result)
 	__attribute__((visibility("default")));
 
-void (*intercept_hook_point_clone_child)(void)
+void (*intercept_hook_point_clone_child)(
+	unsigned long, unsigned long,
+	void *, void *, unsigned)
 	__attribute__((visibility("default")));
-void (*intercept_hook_point_clone_parent)(long)
+void (*intercept_hook_point_clone_parent)(
+	long *, unsigned long, unsigned long,
+	void *, void *, unsigned)
 	__attribute__((visibility("default")));
 
 bool debug_dumps_on;
@@ -701,12 +705,20 @@ intercept_routine(struct context *context)
 struct wrapper_ret
 intercept_routine_post_clone(struct context *context)
 {
+	struct syscall_desc desc;
+	get_syscall_in_context(context, &desc);
 	if (context->rax == 0) {
 		if (intercept_hook_point_clone_child != NULL)
-			intercept_hook_point_clone_child();
+			intercept_hook_point_clone_child(
+				desc.args[0], desc.args[1],
+				(void *)desc.args[2], (void *)desc.args[3],
+				desc.args[4]);
 	} else {
 		if (intercept_hook_point_clone_parent != NULL)
-			intercept_hook_point_clone_parent(context->rax);
+			intercept_hook_point_clone_parent(
+				&context->rax, desc.args[0], desc.args[1],
+				(void *)desc.args[2], (void *)desc.args[3],
+				desc.args[4]);
 	}
 
 	return (struct wrapper_ret){.rax = context->rax, .rdx = 1 };

test/test_clone_thread_preload.c

@@ -33,7 +33,8 @@
 /*
  * This library's purpose is to hook the syscalls of the program
  * built from test_clone_thread.c, and to check the
- * intercept_hook_point_clone_child hook point while doing so.
+ * intercept_hook_point_clone_child and intercept_hook_point_clone_parent
+ * hook point while doing so.
  *
  * See also: examples/fork_ban.c about forking a new process.
  */
@@ -48,7 +49,15 @@
 #include <syscall.h>
 #include <stdio.h>
 
-static long flags = -1;
+typedef struct {
+	unsigned long clone_flags;
+	unsigned long newsp;
+	void *parent_tid;
+	void *child_tid;
+	unsigned tid;
+} clone_args_t;
+
+static clone_args_t clone_args;
 
 static int
 hook(long syscall_number,
@@ -57,9 +66,6 @@ hook(long syscall_number,
 	long arg4, long arg5,
 	long *result)
 {
-	(void) arg2;
-	(void) arg3;
-	(void) arg4;
 	(void) arg5;
 	(void) result;
 
@@ -80,8 +86,13 @@ hook(long syscall_number,
 	 * therefore the return value (the child's pid) can not be observed,
 	 * or modified.
 	 */
-	if (syscall_number == SYS_clone && (arg1 != 0))
-		flags = arg0;
+	if (syscall_number == SYS_clone && (arg1 != 0)) {
+		clone_args.clone_flags = arg0;
+		clone_args.newsp = arg1;
+		clone_args.parent_tid = (void *) arg2;
+		clone_args.child_tid = (void *) arg3;
+		clone_args.tid = arg4;
+	}
 
 	return 1;
 }
@@ -96,11 +107,38 @@ hook(long syscall_number,
  * of the clone syscall.
  */
 static void
-hook_child(void)
+hook_child(unsigned long clone_flags,
+	unsigned long newsp,
+	void *parent_tid,
+	void *child_tid,
+	unsigned tid)
 {
+
 	static const char msg[] = "clone_hook_child called\n";
 
-	assert(flags != -1);
+	assert(clone_flags == clone_args.clone_flags);
+	assert(newsp == clone_args.newsp);
+	assert(parent_tid == clone_args.parent_tid);
+	assert(child_tid == clone_args.child_tid);
+	assert(tid == clone_args.tid);
+	syscall_no_intercept(SYS_write, 1, msg, sizeof(msg));
+}
+
+static void
+hook_parent(long *ret,
+	unsigned long clone_flags,
+	unsigned long newsp,
+	void *parent_tid,
+	void *child_tid,
+	unsigned tid) {
+	static const char msg[] = "clone_hook_parent called\n";
+
+	(void) ret;
+	assert(clone_flags == clone_args.clone_flags);
+	assert(newsp == clone_args.newsp);
+	assert(parent_tid == clone_args.parent_tid);
+	assert(child_tid == clone_args.child_tid);
+	assert(tid == clone_args.tid);
 	syscall_no_intercept(SYS_write, 1, msg, sizeof(msg));
 }
 
@@ -109,4 +147,5 @@ init(void)
 {
 	intercept_hook_point = hook;
 	intercept_hook_point_clone_child = hook_child;
+	intercept_hook_point_clone_parent = hook_parent;
 }