Timeout error (#1173)

* Implement timeout state and new error for such case

* Adjust test_i386_loop sample

* Adjust test_i386_loop test

Backports commit 3a3bc0c22de5453335dfb597a95dbda07c9f47a2 from unicorn

include/uc_priv.h

@@ -262,6 +262,7 @@ struct uc_struct {
     bool stop_request;  // request to immediately stop emulation - for uc_emu_stop()
     bool quit_request;  // request to quit the current TB, but continue to emulate - for uc_mem_protect()
     bool emulation_done;  // emulation is done by uc_emu_start()
+    bool timed_out;     // emulation timed out, uc_emu_start() will result in EC_ERR_TIMEOUT
     QemuThread timer;   // timer for emulation timeout
     uint64_t timeout;   // timeout for uc_emu_start()
 

include/unicorn/unicorn.h

@@ -170,7 +170,8 @@ typedef enum uc_err {
     UC_ERR_FETCH_UNALIGNED,  // Unaligned fetch
     UC_ERR_HOOK_EXIST,  // hook for this event already existed
     UC_ERR_RESOURCE,    // Insufficient resource: uc_emu_start()
-    UC_ERR_EXCEPTION // Unhandled CPU exception
+    UC_ERR_EXCEPTION, // Unhandled CPU exception
+    UC_ERR_TIMEOUT // Emulation timed out
 } uc_err;
 
 

samples/sample_x86.c

@@ -382,9 +382,9 @@ static void test_i386_loop(void)
     // emulate machine code in 2 seconds, so we can quit even
     // if the code loops
     err = uc_emu_start(uc, ADDRESS, ADDRESS + sizeof(X86_CODE32_LOOP) - 1, 2 * UC_SECOND_SCALE, 0);
-    if (err) {
-        printf("Failed on uc_emu_start() with error returned %u: %s\n",
-                err, uc_strerror(err));
+    if (err != UC_ERR_TIMEOUT) {
+        printf("Failed on uc_emu_start() with error returned %u: %s, expected UC_ERR_TIMEOUT\n",
+               err, uc_strerror(err));
     }
 
     // now print out some registers

tests/unit/test_x86.c

@@ -379,7 +379,7 @@ static void test_i386_loop(void **state)
     // emulate machine code in 2 seconds, so we can quit even
     // if the code loops
     err = uc_emu_start(uc, address, address+sizeof(code), 2*UC_SECOND_SCALE, 0);
-    uc_assert_success(err);
+    uc_assert_err(err, UC_ERR_TIMEOUT);
 
     // verify register values
     uc_assert_success(uc_reg_read(uc, UC_X86_REG_ECX, &r_ecx));

uc.c

@@ -103,6 +103,8 @@ const char *uc_strerror(uc_err code)
             return "Insufficient resource (UC_ERR_RESOURCE)";
         case UC_ERR_EXCEPTION:
             return "Unhandled CPU exception (UC_ERR_EXCEPTION)";
+        case UC_ERR_TIMEOUT:
+            return "Emulation timed out (UC_ERR_TIMEOUT)";
     }
 }
 
@@ -530,6 +532,7 @@ static void *_timeout_fn(void *arg)
 
     // timeout before emulation is done?
     if (!uc->emulation_done) {
+        uc->timed_out = true;
         // force emulation to stop
         uc_emu_stop(uc);
     }
@@ -561,6 +564,7 @@ uc_err uc_emu_start(uc_engine* uc, uint64_t begin, uint64_t until, uint64_t time
     uc->invalid_error = UC_ERR_OK;
     uc->block_full = false;
     uc->emulation_done = false;
+    uc->timed_out = false;
 
     switch(uc->arch) {
         default:
@@ -663,6 +667,10 @@ uc_err uc_emu_start(uc_engine* uc, uint64_t begin, uint64_t until, uint64_t time
         qemu_thread_join(&uc->timer);
     }
 
+    if (uc->timed_out) {
+        return UC_ERR_TIMEOUT;
+    }
+
     return uc->invalid_error;
 }