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

2 files changed, 49 insertions, 6 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
diff --git a/lib/darwin/inject.c b/lib/darwin/inject.c
index 4e715d5..a74b057 100644
--- a/lib/darwin/inject.c
+++ b/lib/darwin/inject.c
@@ -390,7 +390,7 @@ got_symbol:;
 static int do_baton(const char *filename, size_t filelen, bool is64,
                     mach_vm_address_t target_stackpage_end,
                     mach_vm_address_t *target_stack_top_p,
-                    uint64_t sym_addrs[static 4],
+                    uint64_t sym_addrs[static 5],
                     const struct shuttle *shuttle, size_t nshuttle,
                     struct shuttle **target_shuttle_p,
                     semaphore_t *sem_port_p,
@@ -398,7 +398,7 @@ static int do_baton(const char *filename, size_t filelen, bool is64,
                     char **error) {
     int ret;
 
-    size_t baton_len = 7 * (is64 ? 8 : 4);
+    size_t baton_len = 8 * (is64 ? 8 : 4);
     size_t shuttles_len = nshuttle * sizeof(struct shuttle);
     size_t filelen_rounded = (filelen + 7) & ~7;
     size_t total_len = baton_len + shuttles_len + filelen_rounded;
@@ -480,6 +480,7 @@ static int do_baton(const char *filename, size_t filelen, bool is64,
         sym_addrs[1],
         sym_addrs[2],
         sym_addrs[3],
+        sym_addrs[4],
         target_stack_top + baton_len + shuttles_len,
         sem_port,
         nshuttle
@@ -544,10 +545,12 @@ int substitute_dlopen_in_pid(int pid, const char *filename, int options,
     if ((ret = find_foreign_images(task, images, 3, error)) > 0)
         goto fail;
 
-    uint64_t pthread_create_addr, dlopen_addr, dlsym_addr, munmap_addr;
+    uint64_t pthread_create_addr, pthread_detach_addr;
+    uint64_t dlopen_addr, dlsym_addr, munmap_addr;
     cpu_type_t cputype;
     if (ret == FFI_SHORT_CIRCUIT) {
         pthread_create_addr = (uint64_t) pthread_create;
+        pthread_detach_addr = (uint64_t) pthread_detach;
         dlopen_addr = (uint64_t) dlopen;
         dlsym_addr = (uint64_t) dlsym;
         munmap_addr = (uint64_t) munmap;
@@ -570,7 +573,7 @@ int substitute_dlopen_in_pid(int pid, const char *filename, int options,
             } syms[2];
         } libs[3] = {
             {images[0].address, 2, {{"_dlopen", 0}, {"_dlsym", 0}}},
-            {images[1].address, 1, {{"_pthread_create", 0}}},
+            {images[1].address, 2, {{"_pthread_create", 0}, {"_pthread_detach", 0}}},
             {images[2].address, 1, {{"_munmap", 0}}},
         };
 
@@ -602,6 +605,8 @@ int substitute_dlopen_in_pid(int pid, const char *filename, int options,
         dlopen_addr = libs[0].syms[0].symaddr;
         dlsym_addr = libs[0].syms[1].symaddr;
         pthread_create_addr = libs[1].syms[0].symaddr;
+        pthread_detach_addr = libs[1].syms[1].symaddr;
+        munmap_addr = libs[2].syms[0].symaddr;
     }
 
     UNUSED
@@ -632,7 +637,11 @@ int substitute_dlopen_in_pid(int pid, const char *filename, int options,
         goto fail;
     }
 
-    uint64_t sym_addrs[] = {pthread_create_addr, dlopen_addr, dlsym_addr, munmap_addr};
+    uint64_t sym_addrs[] = {pthread_create_addr,
+                            pthread_detach_addr,
+                            dlopen_addr,
+                            dlsym_addr,
+                            munmap_addr};
     mach_vm_address_t target_stack_top;
     if ((ret = do_baton(filename, filelen, cputype & CPU_ARCH_ABI64,
                         target_code_page, &target_stack_top,