right, fix cleanup. (compared to the old system, this avoids busywaiting, and properly frees the thread resources)

1 files changed, 35 insertions, 1 deletions

diff --git a/lib/darwin/inject-asm-raw.c b/lib/darwin/inject-asm-raw.c
index 9b272e7..ca316f1 100644
--- a/lib/darwin/inject-asm-raw.c
+++ b/lib/darwin/inject-asm-raw.c
@@ -6,8 +6,14 @@
 #define _PAGE_SIZE 0x1000
 #endif
 
+/* This is somewhat more complicated than it has to be because it does not use
+ * pthread_join, which depends on pthread_self, which would need to be
+ * initialized manually; the format of this has changed in the past, and could
+ * again. */
+
 struct baton {
     int (*pthread_create)(int *, void *, void *(*)(void *), void *);
+    int (*pthread_detach)(int);
     void *(*dlopen)(const char *, int);
     void *(*dlsym)(void *, const char *);
     int (*munmap)(void *, long);
@@ -22,8 +28,9 @@ static int bsd_thread_func(void *);
 __attribute__((fastcall))
 #endif
 void entry(struct baton *baton) {
-    int pt;
+    int pt = 0;
     baton->pthread_create(&pt, 0, (void *) bsd_thread_func, baton);
+    baton->pthread_detach(pt);
     manual_syscall(361 /* bsdthread_terminate */, 0, 0, 0, baton->sem_port);
     ((void (*)()) 0xbad)();
 }
@@ -39,6 +46,33 @@ static int bsd_thread_func(void *arg) {
 
     }
     manual_syscall(-36 /* semaphore_wait_trap */, baton->sem_port, 0, 0, 0);
+#ifndef __i386__
+    /* since we're munmapping our own code, this must be optimized into a jump
+     * (taill call elimination) */
     unsigned long ptr = (unsigned long) baton & ~(_PAGE_SIZE - 1);
     return baton->munmap((void *) ptr, 0x2000);
+#else
+    /* i386 can't normally eliminate tail calls in caller-cleanup calling
+     * conventions, unless the number of arguments is the same, so use a nasty
+     * hack */
+    extern int jump_to_munmap(void *);
+    return jump_to_munmap(baton);
+#endif
 }
+#ifdef __i386__
+/* yuck */
+asm("jmp _entry;"
+    ".globl _jump_to_munmap;"
+    "_jump_to_munmap:"
+        "push %ebp;"
+        "mov %esp, %ebp;"
+        "sub $0x400, %ebp;"
+        "mov 8(%esp), %edx;" /* baton */
+        "mov 16(%edx), %eax;" /* munmap */
+        "and $~0xfff, %edx;"
+        "mov %edx, 8(%ebp);"
+        "movl $0x2000, 12(%ebp);"
+        "add $3, %eax;" /* !? */
+        "jmp *%eax;"
+);
+#endif