Rework API for inline hooking

This both simplifies and complicates things, but probably hopefully
maybe simplifies things overall. Certainly in cases like the L4D1 demo
thing where there's 3 inline hooks at once, it seems simpler to be able
to batch the fallible stuff to avoid rollbacks. In cases where you only
need one hook, it's a bit more verbose, but what can you do.

Thanks bill for discussing this with me pretty exhaustively and giving a
lot of good input.

I think both of us still kind of hate it actually.

1 files changed, 16 insertions, 4 deletions

diff --git a/test/hook.test.c b/test/hook.test.c
index 9e7cfa9..625fdbf 100644
--- a/test/hook.test.c
+++ b/test/hook.test.c
@@ -30,16 +30,28 @@ __attribute__((noinline)) static int func2(int a, int b) { return a - b; }
 static int (*orig_func2)(int, int);
 static int hook2(int a, int b) { return orig_func2(a, b) + 5; }
 
+// basic reimplementation of old API to support existing test cases.
+// XXX: we could probably have tests at the boundaries of the new API too,
+// although the current tests are only testing for regressions in x86 jmp logic.
+static inline void *test_hook_inline(void *func, void *target) {
+	void *trampoline;
+	struct hook_inline_prep_ret prep = hook_inline_prep(func, &trampoline);
+	if (prep.err) return 0;
+	if (!hook_inline_mprot(prep.prologue)) return 0;
+	hook_inline_commit(prep.prologue, target);
+	return trampoline;
+}
+
 TEST("Inline hooks should be able to wrap the original function") {
 	if (!hook_init()) return false;
-	orig_func1 = (testfunc)hook_inline((void *)&func1, (void *)&hook1);
+	orig_func1 = (testfunc)test_hook_inline((void *)&func1, (void *)&hook1);
 	if (!orig_func1) return false;
 	return func1(5, 5) == 15;
 }
 
 TEST("Inline hooks should be removable again") {
 	if (!hook_init()) return false;
-	orig_func1 = (testfunc)hook_inline((void *)&func1, (void *)&hook1);
+	orig_func1 = (testfunc)test_hook_inline((void *)&func1, (void *)&hook1);
 	if (!orig_func1) return false;
 	unhook_inline((void *)orig_func1);
 	return func1(5, 5) == 10;
@@ -47,9 +59,9 @@ TEST("Inline hooks should be removable again") {
 
 TEST("Multiple functions should be able to be inline-hooked at once") {
 	if (!hook_init()) return false;
-	orig_func1 = (testfunc)hook_inline((void *)&func1, (void *)&hook1);
+	orig_func1 = (testfunc)test_hook_inline((void *)&func1, (void *)&hook1);
 	if (!orig_func1) return false;
-	orig_func2 = (testfunc)hook_inline((void *)&func2, (void *)&hook2);
+	orig_func2 = (testfunc)test_hook_inline((void *)&func2, (void *)&hook2);
 	if (!orig_func2) return false;
 	return func2(5, 5) == 5;
 }