phpdbg_sigsafe.c

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#include "phpdbg_sigsafe.h"
#include "phpdbg.h"
 
ZEND_EXTERN_MODULE_GLOBALS(phpdbg)
 
#define STR(x) #x
#define EXP_STR(x) STR(x)
 
static void* zend_mm_mem_alloc(zend_mm_storage *storage, size_t size, size_t alignment) {
 
    if (EXPECTED(size <= PHPDBG_SIGSAFE_MEM_SIZE && !PHPDBG_G(sigsafe_mem).allocated)) {
        PHPDBG_G(sigsafe_mem).allocated = 1;
        return (void *) (((size_t) PHPDBG_G(sigsafe_mem).mem & ~(alignment - 1)) + alignment);
    }
 
    zend_quiet_write(PHPDBG_G(io)[PHPDBG_STDERR].fd, ZEND_STRL("Tried to allocate more than " EXP_STR(PHPDBG_SIGSAFE_MEM_SIZE) " bytes from stack memory in signal handler ... bailing out of signal handler\n"));
 
    if (*EG(bailout)) {
        LONGJMP(*EG(bailout), FAILURE);
    }
 
    zend_quiet_write(PHPDBG_G(io)[PHPDBG_STDERR].fd, ZEND_STRL("Bailed out without a bailout address in signal handler!\n"));
 
    return NULL;
}
 
static void zend_mm_mem_free(zend_mm_storage *storage, void *ptr, size_t size) {
}
 
void phpdbg_set_sigsafe_mem(char *buffer) {
    phpdbg_signal_safe_mem *mem = &PHPDBG_G(sigsafe_mem);
    const zend_mm_handlers phpdbg_handlers = {
        zend_mm_mem_alloc,
        zend_mm_mem_free,
        NULL,
        NULL,
    };
 
    mem->mem = buffer;
    mem->allocated = 0;
 
    mem->heap = zend_mm_startup_ex(&phpdbg_handlers, NULL, 0);
 
    mem->old_heap = zend_mm_set_heap(mem->heap);
}
 
zend_mm_heap *phpdbg_original_heap_sigsafe_mem(void) {
    return PHPDBG_G(sigsafe_mem).old_heap;
}
 
void phpdbg_clear_sigsafe_mem(void) {
    zend_mm_set_heap(phpdbg_original_heap_sigsafe_mem());
    PHPDBG_G(sigsafe_mem).mem = NULL;
}
 
bool phpdbg_active_sigsafe_mem(void) {
    return !!PHPDBG_G(sigsafe_mem).mem;
}