diff options
Diffstat (limited to 'lib/objc.c')
| -rw-r--r-- | lib/objc.c | 205 |
1 files changed, 0 insertions, 205 deletions
diff --git a/lib/objc.c b/lib/objc.c deleted file mode 100644 index 398e3e7..0000000 --- a/lib/objc.c +++ /dev/null @@ -1,205 +0,0 @@ -#if defined(__APPLE__) -#include "substitute.h" -#include "substitute-internal.h" -#include "objc.h" -#include <stddef.h> -#include <pthread.h> -#include <mach/mach.h> -#include <sys/mman.h> -#include <sys/queue.h> -#include <errno.h> - -/* These trampolines will call e->func(e->arg1, e->arg2), and jump to there, - * preserving all arguments. imp_implementationWithBlock would be easier and - * maybe a bit faster, but it's impossible to avoid throwing away registers - * without having to ask whether the selector is stret or not. */ - -struct tramp_info_page_header { - uint32_t magic; - uint32_t version; - struct tramp_info_page_entry *first_free; - size_t nfree; - LIST_ENTRY(tramp_info_page_header) free_pages; -}; - -enum { - TRAMP_MAGIC = 0xf00df17e, - TRAMP_VERSION = 0, -}; - -struct tramp_info_page_entry { - union { - struct tramp_info_page_entry *next_free; - void *func; - }; - void *arg1; - void *arg2; -}; - -_Static_assert(TRAMP_INFO_PAGE_ENTRY_SIZE == sizeof(struct tramp_info_page_entry), - "TRAMP_INFO_PAGE_ENTRY_SIZE"); -_Static_assert(sizeof(struct tramp_info_page_header) + - TRAMPOLINES_PER_PAGE * sizeof(struct tramp_info_page_entry) <= _PAGE_SIZE, - "header+entries too big"); - -static pthread_mutex_t tramp_mutex = PTHREAD_MUTEX_INITIALIZER; -LIST_HEAD(tramp_info_page_list, tramp_info_page_header) - tramp_free_page_list = LIST_HEAD_INITIALIZER(tramp_info_page_list); - -extern char remap_start[]; - -static int get_trampoline(void *func, void *arg1, void *arg2, void *tramp_ptr) { - int ret, rerrno = 0; - pthread_mutex_lock(&tramp_mutex); - - struct tramp_info_page_header *header = LIST_FIRST(&tramp_free_page_list); - if (!header) { - if (PAGE_SIZE > _PAGE_SIZE) - panic("%s: strange PAGE_SIZE %x\n", __func__, PAGE_SIZE); - void *new_pages = mmap(NULL, _PAGE_SIZE * 2, PROT_READ | PROT_WRITE, - MAP_SHARED | MAP_ANON, -1, 0); - if (new_pages == MAP_FAILED) { - ret = SUBSTITUTE_ERR_OOM; - rerrno = errno; - goto out; - } - vm_address_t tramp_page = (vm_address_t) new_pages; - vm_prot_t cur_prot, max_prot; - kern_return_t kr = vm_remap( - mach_task_self(), - &tramp_page, - _PAGE_SIZE, - _PAGE_SIZE - 1, - VM_FLAGS_OVERWRITE | VM_FLAGS_FIXED, - mach_task_self(), - (vm_address_t) remap_start, - FALSE, /* copy */ - &cur_prot, - &max_prot, - VM_INHERIT_NONE); - if (kr != KERN_SUCCESS || tramp_page != (vm_address_t) new_pages) { - ret = SUBSTITUTE_ERR_VM; - goto out; - } - header = new_pages + _PAGE_SIZE * 2 - sizeof(*header); - header->magic = TRAMP_MAGIC; - header->version = TRAMP_VERSION; - header->first_free = NULL; - header->nfree = TRAMPOLINES_PER_PAGE; - LIST_INSERT_HEAD(&tramp_free_page_list, header, free_pages); - } - - void *page = (void *) (((uintptr_t) header) & ~(_PAGE_SIZE - 1)); - struct tramp_info_page_entry *entries = page; - struct tramp_info_page_entry *entry = header->first_free; - if (entry == NULL) { - entry = &entries[TRAMPOLINES_PER_PAGE - header->nfree]; - entry->next_free = NULL; - } - - header->first_free = entry->next_free; - if (--header->nfree == 0) - LIST_REMOVE(header, free_pages); - - entry->func = func; - entry->arg1 = arg1; - entry->arg2 = arg2; - void *tramp = (page - PAGE_SIZE) + (entry - entries) * TRAMPOLINE_SIZE; -#ifdef __arm__ - tramp += 1; -#endif - *(void **) tramp_ptr = tramp; - ret = SUBSTITUTE_OK; -out: - pthread_mutex_unlock(&tramp_mutex); - errno = rerrno; - return ret; -} - -static void free_trampoline(void *tramp) { - pthread_mutex_lock(&tramp_mutex); - void *page = (void *) (((uintptr_t) tramp) & ~(_PAGE_SIZE - 1)); - size_t i = (tramp - page) / TRAMPOLINE_SIZE; - struct tramp_info_page_entry *entries = page + _PAGE_SIZE; - struct tramp_info_page_entry *entry = &entries[i]; - struct tramp_info_page_header *header = page + 2 * _PAGE_SIZE - sizeof(*header); - - if (header->magic != TRAMP_MAGIC) - panic("%s: bad pointer\n", __func__); - if (header->version != TRAMP_VERSION) { - /* shouldn't happen, but just in case multiple versions of this library - * are mixed up */ - return; - } - - entry->next_free = header->first_free; - header->first_free = entry; - header->nfree++; - if (header->nfree == 1) - LIST_INSERT_HEAD(&tramp_free_page_list, header, free_pages); - else if (header->nfree == TRAMPOLINES_PER_PAGE && - /* have others? */ - (LIST_FIRST(&tramp_free_page_list) != header || - LIST_NEXT(header, free_pages))) { - /* free the trampoline and info pages */ - LIST_REMOVE(header, free_pages); - munmap(page, 2 * _PAGE_SIZE); - } - - pthread_mutex_unlock(&tramp_mutex); -} - -static IMP dereference(IMP *old_ptr, UNUSED void *_) { - return *old_ptr; -} - -EXPORT -int substitute_hook_objc_message(Class class, SEL selector, void *replacement, - void *old_ptr, bool *created_imp_ptr) { - int ret; - Method meth = class_getInstanceMethod(class, selector); - if (meth == NULL) - return SUBSTITUTE_ERR_NO_SUCH_SELECTOR; - const char *types = method_getTypeEncoding(meth); - - if (created_imp_ptr) - *created_imp_ptr = false; - - /* temporary trampoline just tries again */ - IMP temp = NULL; - if (old_ptr) { - if ((ret = get_trampoline(dereference, old_ptr, NULL, &temp))) - return ret; - *(IMP *) old_ptr = temp; - } - - IMP old = class_replaceMethod(class, selector, replacement, types); - if (old) { - if (old_ptr) - *(IMP *) old_ptr = old; - } else { - if (old_ptr) { - Class super = class_getSuperclass(class); - if (!super) { - /* this ought to only be possible if the method was removed in - * the meantime, since we found the method above and it - * couldn't have been found in a superclass, but the objc2 - * runtime doesn't allow removing methods. */ - panic("%s: no superclass but the method didn't exist\n", __func__); - } - ret = get_trampoline(class_getMethodImplementation, super, selector, old_ptr); - if (created_imp_ptr) - *created_imp_ptr = true; - } - } - - if (temp) - free_trampoline(temp); - return SUBSTITUTE_OK; -} - -EXPORT -void substitute_free_created_imp(IMP imp) { - free_trampoline(imp); -} -#endif |