koekeishiya#725 cleanup mach bootstrap code

src/osax/mach_bootstrap.c

@@ -1,9 +1,10 @@
 #include <mach/mach.h>
 #include <pthread.h>
+#include <pthread_spis.h>
 #include <unistd.h>
 #include <dlfcn.h>
 
-extern void _pthread_set_self(char *);
+extern void _pthread_set_self(pthread_t *);
 
 static void drop_privileges(void)
 {
@@ -23,22 +24,10 @@ static void *mach_load_payload(void *context)
     return NULL;
 }
 
-void mach_bootstrap_entry_point(char *param)
+void mach_bootstrap_entry_point(void)
 {
-    int policy;
     pthread_t thread;
-    pthread_attr_t attr;
-    struct sched_param sched;
-
-    _pthread_set_self(param);
-    pthread_attr_init(&attr);
-    pthread_attr_getschedpolicy(&attr, &policy);
-    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
-    pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
-    sched.sched_priority = sched_get_priority_max(policy);
-    pthread_attr_setschedparam(&attr, &sched);
-    pthread_create(&thread, &attr, &mach_load_payload, NULL);
-    pthread_attr_destroy(&attr);
-
+    _pthread_set_self(&thread);
+    pthread_create_from_mach_thread(&thread, NULL, &mach_load_payload, NULL);
     thread_suspend(mach_thread_self());
 }

src/osax/mach_loader.c

@@ -97,9 +97,8 @@ bool mach_loader_inject_payload(pid_t pid)
 
 #ifdef __arm64__
     arm_thread_state64_t thread_state = {};
-    thread_state.__x[0] = (uint64_t) stack;
     thread_state.__pc = (uint64_t) code + (uint64_t)(((void *) bootstrap_entry) - image);
-    thread_state.__sp = (uint64_t) (stack + (stack_size / 2) - 8);
+    thread_state.__sp = (uint64_t) (stack + (stack_size / 2));
 
     kern_return_t error = thread_create_running(task, ARM_THREAD_STATE64, (thread_state_t)&thread_state, ARM_THREAD_STATE64_COUNT, &thread);
     if (error != KERN_SUCCESS) {
@@ -108,7 +107,6 @@ bool mach_loader_inject_payload(pid_t pid)
     }
 #else
     x86_thread_state64_t thread_state = {};
-    thread_state.__rdi = (uint64_t) stack;
     thread_state.__rip = (uint64_t) code + (uint64_t)(((void *) bootstrap_entry) - image);
     thread_state.__rsp = (uint64_t) (stack + (stack_size / 2) - 8);