1 files changed, 63 insertions, 11 deletions

diff --git a/debuggerd/crasher.c b/debuggerd/crasher.c
index 00652e9..630d980 100644
--- a/debuggerd/crasher.c
+++ b/debuggerd/crasher.c
@@ -20,6 +20,7 @@
 void crash1(void);
 void crashnostack(void);
 void maybeabort(void);
+int do_action(const char* arg);
 
 static void debuggerd_connect()
 {
@@ -34,6 +35,18 @@ static void debuggerd_connect()
     }
 }
 
+int smash_stack(int i) {
+    printf("crasher: deliberately corrupting stack...\n");
+    // Unless there's a "big enough" buffer on the stack, gcc
+    // doesn't bother inserting checks.
+    char buf[8];
+    // If we don't write something relatively unpredicatable
+    // into the buffer and then do something with it, gcc
+    // optimizes everything away and just returns a constant.
+    *(int*)(&buf[7]) = (uintptr_t) &buf[0];
+    return *(int*)(&buf[0]);
+}
+
 void test_call1()
 {
     *((int*) 32) = 1;
@@ -74,24 +87,63 @@ int ctest()
     return 0;
 }
 
-int main(int argc, char **argv)
+static void* thread_callback(void* raw_arg)
+{
+    return (void*) do_action((const char*) raw_arg);
+}
+
+int do_action_on_thread(const char* arg)
 {
+    pthread_t t;
+    pthread_create(&t, NULL, thread_callback, (void*) arg);
+    void* result = NULL;
+    pthread_join(t, &result);
+    return (int) result;
+}
+
+__attribute__((noinline)) int crash3(int a) {
+   *((int*) 0xdead) = a;
+   return a*4;
+}
+
+__attribute__((noinline)) int crash2(int a) {
+   a = crash3(a) + 2;
+   return a*3;
+}
+
+__attribute__((noinline)) int crash(int a) {
+   a = crash2(a) + 1;
+   return a*2;
+}
+
+int do_action(const char* arg)
+{
+    if(!strncmp(arg, "thread-", strlen("thread-"))) {
+        return do_action_on_thread(arg + strlen("thread-"));
+    }
+
+    if(!strcmp(arg,"smash-stack")) return smash_stack(42);
+    if(!strcmp(arg,"nostack")) crashnostack();
+    if(!strcmp(arg,"ctest")) return ctest();
+    if(!strcmp(arg,"exit")) exit(1);
+    if(!strcmp(arg,"crash")) return crash(42);
+    if(!strcmp(arg,"abort")) maybeabort();
+
     pthread_t thr;
     pthread_attr_t attr;
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+    pthread_create(&thr, &attr, test_thread, 0);
+    while(1) sleep(1);
+}
 
-    fprintf(stderr,"crasher: " __TIME__ "!@\n");
+int main(int argc, char **argv)
+{
+    fprintf(stderr,"crasher: built at " __TIME__ "!@\n");
     fprintf(stderr,"crasher: init pid=%d tid=%d\n", getpid(), gettid());
 
     if(argc > 1) {
-        if(!strcmp(argv[1],"nostack")) crashnostack();
-        if(!strcmp(argv[1],"ctest")) return ctest();
-        if(!strcmp(argv[1],"exit")) exit(1);
-        if(!strcmp(argv[1],"abort")) maybeabort();
-        
-        pthread_attr_init(&attr);
-        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
-        pthread_create(&thr, &attr, test_thread, 0);
-        while(1) sleep(1);
+        return do_action(argv[1]);
     } else {
         crash1();
 //        *((int*) 0) = 42;