Strengthen unhook smoke with pre/post verification

Author: YinMo19

.github/workflows/ci.yml

@@ -63,6 +63,7 @@ jobs:
           DYLIB="$PWD/target/aarch64-apple-darwin/debug/examples/libinstrument_unhook_restore.dylib"
           OUT=$(DYLD_INSERT_LIBRARIES="$DYLIB" examples/instrument_unhook_restore/app)
           echo "$OUT"
+          [[ "$OUT" == *"hooked_calc(3, 4) = 123"* ]]
           [[ "$OUT" == *"calc(3, 4) = 7"* ]]
 
           cc -O0 -fno-inline examples/inline_hook_far/target.c -o examples/inline_hook_far/app
@@ -137,6 +138,7 @@ jobs:
           DYLIB="$PWD/target/x86_64-apple-darwin/debug/examples/libinstrument_unhook_restore.dylib"
           OUT=$(DYLD_INSERT_LIBRARIES="$DYLIB" examples/instrument_unhook_restore/app)
           echo "$OUT"
+          [[ "$OUT" == *"hooked_calc(3, 4) = 123"* ]]
           [[ "$OUT" == *"calc(3, 4) = 7"* ]]
 
           cc -O0 -fno-inline examples/inline_hook_far/target.c -o examples/inline_hook_far/app
@@ -201,6 +203,13 @@ jobs:
           echo "$OUT"
           [[ "$OUT" == *"calc(4, 5) = 99"* ]]
 
+          cc -O0 -fno-inline -rdynamic examples/instrument_unhook_restore/target.c -o examples/instrument_unhook_restore/app
+          SO="$PWD/target/x86_64-unknown-linux-gnu/debug/examples/libinstrument_unhook_restore.so"
+          OUT=$(LD_PRELOAD="$SO" examples/instrument_unhook_restore/app)
+          echo "$OUT"
+          [[ "$OUT" == *"hooked_calc(3, 4) = 123"* ]]
+          [[ "$OUT" == *"calc(3, 4) = 7"* ]]
+
           cc -O0 -fno-inline -rdynamic examples/inline_hook_far/target.c -o examples/inline_hook_far/app
           SO="$PWD/target/x86_64-unknown-linux-gnu/debug/examples/libinline_hook_far.so"
           OUT=$(LD_PRELOAD="$SO" examples/inline_hook_far/app)
@@ -273,6 +282,7 @@ jobs:
           SO="$PWD/target/aarch64-unknown-linux-gnu/debug/examples/libinstrument_unhook_restore.so"
           OUT=$(LD_PRELOAD="$SO" examples/instrument_unhook_restore/app)
           echo "$OUT"
+          [[ "$OUT" == *"hooked_calc(3, 4) = 123"* ]]
           [[ "$OUT" == *"calc(3, 4) = 7"* ]]
 
           cc -O0 -fno-inline -rdynamic examples/instrument_adrp_no_original/target.c -o examples/instrument_adrp_no_original/app

examples/README.md

@@ -40,7 +40,7 @@ Available examples:
 - `x86_64-apple-darwin`: compile coverage for all 4 examples, plus optional `patch_asm` build
 - `aarch64-unknown-linux-gnu`: runtime smoke coverage for all 6 core examples (CI, includes `instrument_adrp_no_original`)
 - `aarch64-unknown-linux-gnu`: plus optional `patch_asm` smoke (`--features patch_asm`)
-- `x86_64-unknown-linux-gnu`: runtime smoke coverage for 4 base examples (CI), plus optional `patch_asm` smoke (`--features patch_asm`)
+- `x86_64-unknown-linux-gnu`: runtime smoke coverage for 5 base examples (CI), plus optional `patch_asm` smoke (`--features patch_asm`)
 
 ## Notes by architecture
 

examples/instrument_unhook_restore/README.md

@@ -5,15 +5,19 @@ Demonstrates `sighook::instrument` + `sighook::unhook`.
 Flow:
 
 1. install an instruction hook
-2. immediately call `unhook` on the same patchpoint
-3. execute target function and verify original behavior is restored
+2. call `calc(3, 4)` once while hook is active and verify hooked value `123`
+3. call `unhook` on the same patchpoint
+4. execute target function again and verify original behavior is restored (`7`)
 
 The callback would force result to `123` if triggered:
 
 - `aarch64`: set `x8 = 120`, `x9 = 3`, then original `add w0, w8, w9` runs
 - `linux x86_64`: set `rax = 123`
 
-Expected runtime output proves callback is not reached after unhook.
+Expected runtime output proves both stages:
+
+- callback is reached before unhook (`hooked_calc(3, 4) = 123`)
+- original behavior is restored after unhook (`calc(3, 4) = 7`)
 
 ## Run (from repository root)
 
@@ -36,5 +40,6 @@ LD_PRELOAD="$PWD/target/debug/examples/libinstrument_unhook_restore.so" examples
 Expected output:
 
 ```text
+hooked_calc(3, 4) = 123
 calc(3, 4) = 7
 ```

examples/instrument_unhook_restore/main.rs

@@ -34,6 +34,12 @@ static INIT_ARRAY: extern "C" fn() = init;
 
 extern "C" fn init() {
     unsafe {
+        let calc_symbol = libc::dlsym(libc::RTLD_DEFAULT, c"calc".as_ptr());
+        if calc_symbol.is_null() {
+            return;
+        }
+        let calc_fn: extern "C" fn(i32, i32) -> i32 = std::mem::transmute(calc_symbol);
+
         let target_address = {
             #[cfg(all(
                 any(target_os = "linux", target_os = "android"),
@@ -66,7 +72,11 @@ extern "C" fn init() {
             }
         };
 
-        if instrument(target_address, on_hit_should_not_run).is_err() {
+        let _ = instrument(target_address, on_hit_should_not_run);
+
+        let hooked = calc_fn(3, 4);
+        println!("hooked_calc(3, 4) = {hooked}");
+        if hooked != 123 {
             return;
         }