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macos: support bounds checking

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* non-process-shared POSIX semaphores aren't supported on
  Darwin, we use the dispatch framework
* dlsym segfaults with RTLD_NEXT from JIT code, so we must not
  even try this for -run.  So we need to know in __bound_init
  if called from -run code, or from normal code, which means passing
  this down also from __bt_init and hence from the stub added in
  tcc_add_btstub
* Darwin uses different structures for <ctype.h> facilities, this
  merely adds a warning about this
* __libc_freeres doesn't exist
* for non -run modus the context (.prog_base member) is constructed
  incorrectly (uses symbol zero for trying to get at the load bias,
  which doesn't really work that way), on Mach-O this errors out
  (and could also error out on ELF).  For now deactivate this, which
  makes backtraces not be symbolic on MacOS for not -run.
This commit is contained in:
Michael Matz 2020-05-22 05:06:08 +02:00
parent 0b3c8360a0
commit 57ba50e611
5 changed files with 36 additions and 17 deletions
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2
lib/Makefile
View File

@ -54,7 +54,7 @@ WIN_O = crt1.o crt1w.o wincrt1.o wincrt1w.o dllcrt1.o dllmain.o
OBJ-i386 = $(I386_O) $(BCHECK_O) $(DSO_O)
OBJ-x86_64 = $(X86_64_O) va_list.o $(BCHECK_O) $(DSO_O)
OBJ-x86_64-osx = $(X86_64_O) va_list.o
OBJ-x86_64-osx = $(X86_64_O) va_list.o $(BCHECK_O)
OBJ-i386-win32 = $(I386_O) chkstk.o $(B_O) $(WIN_O)
OBJ-x86_64-win32 = $(X86_64_O) chkstk.o $(B_O) $(WIN_O)
OBJ-arm64 = $(ARM64_O) $(BCHECK_O) $(DSO_O)

34
lib/bcheck.c
View File

@ -27,6 +27,7 @@
&& !defined(__FreeBSD_kernel__) \
&& !defined(__DragonFly__) \
&& !defined(__OpenBSD__) \
&& !defined(__APPLE__) \
&& !defined(__NetBSD__)
#include <malloc.h>
#endif
@ -98,7 +99,14 @@ static CRITICAL_SECTION bounds_sem;
#include <pthread.h>
#include <dlfcn.h>
#include <errno.h>
#if 0
#ifdef __APPLE__
#include <dispatch/dispatch.h>
static dispatch_semaphore_t bounds_sem;
#define INIT_SEM() bounds_sem = dispatch_semaphore_create(1)
#define EXIT_SEM() dispatch_release(*(dispatch_object_t*)&bounds_sem)
#define WAIT_SEM() if (use_sem) dispatch_semaphore_wait(bounds_sem, DISPATCH_TIME_FOREVER)
#define POST_SEM() if (use_sem) dispatch_semaphore_signal(bounds_sem)
#elif 0
#include <semaphore.h>
static sem_t bounds_sem;
#define INIT_SEM() sem_init (&bounds_sem, 0, 1)
@ -198,7 +206,7 @@ DLL_EXPORT void * __bound_ptr_indir12(void *p, size_t offset);
DLL_EXPORT void * __bound_ptr_indir16(void *p, size_t offset);
DLL_EXPORT void FASTCALL __bound_local_new(void *p1);
DLL_EXPORT void FASTCALL __bound_local_delete(void *p1);
void __bound_init(size_t *);
void __bound_init(size_t *, int);
void __bound_main_arg(char **p);
void __bound_exit(void);
#if !defined(_WIN32)
@ -780,9 +788,10 @@ void __bound_siglongjmp(jmp_buf env, int val)
#pragma GCC diagnostic pop
#endif
void __bound_init(size_t *p)
void __bound_init(size_t *p, int mode)
{
dprintf(stderr, "%s, %s(): start\n", __FILE__, __FUNCTION__);
dprintf(stderr, "%s, %s(): start %s\n", __FILE__, __FUNCTION__,
mode < 0 ? "lazy" : mode == 0 ? "normal use" : "for -run");
if (inited) {
WAIT_SEM();
@ -800,9 +809,12 @@ void __bound_init(size_t *p)
#if MALLOC_REDIR
{
void *addr = RTLD_NEXT;
void *addr = mode > 0 ? RTLD_DEFAULT : RTLD_NEXT;
/* tcc -run required RTLD_DEFAULT. Normal usage requires RTLD_NEXT */
/* tcc -run required RTLD_DEFAULT. Normal usage requires RTLD_NEXT,
but using RTLD_NEXT with -run segfaults on MacOS in dyld as the
generated code segment isn't registered with dyld and hence the
caller image of dlsym isn't known to it */
*(void **) (&malloc_redir) = dlsym (addr, "malloc");
if (malloc_redir == NULL) {
dprintf(stderr, "%s, %s(): use RTLD_DEFAULT\n",
@ -877,6 +889,9 @@ void __bound_init(size_t *p)
WAIT_SEM ();
#if HAVE_CTYPE
#ifdef __APPLE__
#warning fill out for MacOS (see <_ctype.h> and <runetype.h>)
#else
/* XXX: Does not work if locale is changed */
tree = splay_insert((size_t) __ctype_b_loc(),
sizeof (unsigned short *), tree);
@ -891,6 +906,7 @@ void __bound_init(size_t *p)
tree = splay_insert((size_t) (*__ctype_toupper_loc() - 128),
384 * sizeof (__int32_t), tree);
#endif
#endif
#if HAVE_ERRNO
tree = splay_insert((size_t) (&errno), sizeof (int), tree);
#endif
@ -985,7 +1001,7 @@ void __attribute__((destructor)) __bound_exit(void)
dprintf(stderr, "%s, %s():\n", __FILE__, __FUNCTION__);
if (inited) {
#if !defined(_WIN32)
#if !defined(_WIN32) && !defined(__APPLE__)
if (print_heap) {
extern void __libc_freeres (void);
__libc_freeres ();
@ -1097,7 +1113,7 @@ void *__bound_malloc(size_t size, const void *caller)
#if MALLOC_REDIR
/* This will catch the first dlsym call from __bound_init */
if (malloc_redir == NULL) {
__bound_init (0);
__bound_init (0, -1);
if (malloc_redir == NULL) {
ptr = &initial_pool[pool_index];
pool_index = (pool_index + size + 15) & ~15;
@ -1259,7 +1275,7 @@ void *__bound_calloc(size_t nmemb, size_t size)
#if MALLOC_REDIR
/* This will catch the first dlsym call from __bound_init */
if (malloc_redir == NULL) {
__bound_init (0);
__bound_init (0, -1);
if (malloc_redir == NULL) {
ptr = &initial_pool[pool_index];
pool_index = (pool_index + size + 15) & ~15;

8
lib/bt-exe.c
View File

@ -12,12 +12,12 @@ int (*__rt_error)(void*, void*, const char *, va_list);
#endif
__declspec(dllexport)
void __bt_init(rt_context *p, int num_callers)
void __bt_init(rt_context *p, int num_callers, int mode)
{
__attribute__((weak)) int main();
__attribute__((weak)) void __bound_init(void*);
__attribute__((weak)) void __bound_init(void*, int);
struct rt_context *rc = &g_rtctxt;
//fprintf(stderr, "__bt_init %d %p %p\n", num_callers, p->stab_sym, p->bounds_start), fflush(stderr);
//fprintf(stderr, "__bt_init %d %p %p %d\n", num_callers, p->stab_sym, p->bounds_start, mode), fflush(stderr);
if (num_callers) {
memcpy(rc, p, offsetof(rt_context, next));
rc->num_callers = num_callers - 1;
@ -28,7 +28,7 @@ void __bt_init(rt_context *p, int num_callers)
p->next = rc->next, rc->next = p;
}
if (__bound_init && p->bounds_start)
__bound_init(p->bounds_start);
__bound_init(p->bounds_start, mode);
}
/* copy a string and truncate it. */

7
tccelf.c
View File

@ -1388,7 +1388,10 @@ ST_FUNC void tcc_add_btstub(TCCState *s1)
put_ptr(s1, stab_section->link, 0);
section_ptr_add(s, 3 * PTR_SIZE);
/* prog_base */
#ifndef TCC_TARGET_MACHO
/* XXX this relocation is wrong, it uses sym-index 0 (local,undef) */
put_elf_reloc(s1->symtab, s, s->data_offset, R_DATA_PTR, 0);
#endif
section_ptr_add(s, PTR_SIZE);
n = 2 * PTR_SIZE;
#ifdef CONFIG_TCC_BCHECK
@ -1411,11 +1414,11 @@ ST_FUNC void tcc_add_btstub(TCCState *s1)
cstr_printf(&cstr, "__bt_init_dll(0);");
#endif
#endif
cstr_printf(&cstr, "__bt_init(__rt_info,%d);}",
cstr_printf(&cstr, "__bt_init(__rt_info,%d, 0);}",
s1->output_type == TCC_OUTPUT_DLL ? 0 : s1->rt_num_callers + 1);
tcc_compile_string(s1, cstr.data);
cstr_free(&cstr);
set_local_sym(s1, "__rt_info", s, o);
set_local_sym(s1, "___rt_info" + !s1->leading_underscore, s, o);
}
#endif

2
tccrun.c
View File

@ -172,7 +172,7 @@ LIBTCCAPI int tcc_run(TCCState *s1, int argc, char **argv)
#ifdef CONFIG_TCC_BCHECK
if (s1->do_bounds_check) {
if ((p = tcc_get_symbol(s1, "__bound_init")))
((void(*)(void*))p)(bounds_section->data);
((void(*)(void*, int))p)(bounds_section->data, 1);
}
#endif
set_exception_handler();