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Address #466? 

Do not restore pc when returning from top most fiber frame.

Also add JANET_DEBUG config define for various debugging related
configurations. In fiber.c, when debug is enabled we reallocate the
entire stack everytime we push a frame to help uncover use after free
errors.
This commit is contained in:
Calvin Rose 2020-08-17 07:01:58 -05:00
parent 58374623b7
commit 5377e10532
3 changed files with 38 additions and 4 deletions
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1
src/conf/janetconf.h
View File

@ -57,6 +57,7 @@
/* #define JANET_NO_UMASK */
/* Other settings */
/* #define JANET_DEBUG */
/* #define JANET_PRF */
/* #define JANET_NO_UTC_MKTIME */
/* #define JANET_OUT_OF_MEMORY do { printf("janet out of memory\n"); exit(1); } while (0) */

28
src/core/fiber.c
View File

@ -85,6 +85,22 @@ JanetFiber *janet_fiber(JanetFunction *callee, int32_t capacity, int32_t argc, c
return janet_fiber_reset(fiber_alloc(capacity), callee, argc, argv);
}
#ifdef JANET_DEBUG
/* Test for memory issues by reallocating fiber every time we push a stack frame */
static void janet_fiber_refresh_memory(JanetFiber *fiber) {
int32_t n = fiber->capacity;
if (n) {
Janet *newData = malloc(sizeof(Janet) * n);
if (NULL == newData) {
JANET_OUT_OF_MEMORY;
}
memcpy(newData, fiber->data, fiber->capacity * sizeof(Janet));
free(fiber->data);
fiber->data = newData;
}
}
#endif
/* Ensure that the fiber has enough extra capacity */
void janet_fiber_setcapacity(JanetFiber *fiber, int32_t n) {
Janet *newData = realloc(fiber->data, sizeof(Janet) * n);
@ -173,6 +189,10 @@ int janet_fiber_funcframe(JanetFiber *fiber, JanetFunction *func) {
if (fiber->capacity < nextstacktop) {
janet_fiber_setcapacity(fiber, 2 * nextstacktop);
#ifdef JANET_DEBUG
} else {
janet_fiber_refresh_memory(fiber);
#endif
}
/* Nil unset stack arguments (Needed for gc correctness) */
@ -305,6 +325,10 @@ int janet_fiber_funcframe_tail(JanetFiber *fiber, JanetFunction *func) {
if (fiber->capacity < nextstacktop) {
janet_fiber_setcapacity(fiber, 2 * nextstacktop);
#ifdef JANET_DEBUG
} else {
janet_fiber_refresh_memory(fiber);
#endif
}
Janet *stack = fiber->data + fiber->frame;
@ -367,6 +391,10 @@ void janet_fiber_cframe(JanetFiber *fiber, JanetCFunction cfun) {
if (fiber->capacity < nextstacktop) {
janet_fiber_setcapacity(fiber, 2 * nextstacktop);
#ifdef JANET_DEBUG
} else {
janet_fiber_refresh_memory(fiber);
#endif
}
/* Set the next frame */

13
src/core/vm.c
View File

@ -95,6 +95,10 @@ JANET_THREAD_LOCAL jmp_buf *janet_vm_jmp_buf = NULL;
vm_commit(); \
return (sig); \
} while (0)
#define vm_return_no_restore(sig, val) do { \
janet_vm_return_reg[0] = (val); \
return (sig); \
} while (0)
/* Next instruction variations */
#define maybe_collect() do {\
@ -623,7 +627,7 @@ static JanetSignal run_vm(JanetFiber *fiber, Janet in) {
Janet retval = stack[D];
int entrance_frame = janet_stack_frame(stack)->flags & JANET_STACKFRAME_ENTRANCE;
janet_fiber_popframe(fiber);
if (entrance_frame) vm_return(JANET_SIGNAL_OK, retval);
if (entrance_frame) vm_return_no_restore(JANET_SIGNAL_OK, retval);
vm_restore();
stack[A] = retval;
vm_checkgc_pcnext();
@ -633,7 +637,7 @@ static JanetSignal run_vm(JanetFiber *fiber, Janet in) {
Janet retval = janet_wrap_nil();
int entrance_frame = janet_stack_frame(stack)->flags & JANET_STACKFRAME_ENTRANCE;
janet_fiber_popframe(fiber);
if (entrance_frame) vm_return(JANET_SIGNAL_OK, retval);
if (entrance_frame) vm_return_no_restore(JANET_SIGNAL_OK, retval);
vm_restore();
stack[A] = retval;
vm_checkgc_pcnext();
@ -1011,8 +1015,9 @@ static JanetSignal run_vm(JanetFiber *fiber, Janet in) {
retreg = call_nonfn(fiber, callee);
}
janet_fiber_popframe(fiber);
if (entrance_frame)
vm_return(JANET_SIGNAL_OK, retreg);
if (entrance_frame) {
vm_return_no_restore(JANET_SIGNAL_OK, retreg);
}
vm_restore();
stack[A] = retreg;
vm_checkgc_pcnext();