diff options
Diffstat (limited to 'lib/builtins/enable_execute_stack.c')
| -rw-r--r-- | lib/builtins/enable_execute_stack.c | 77 |
1 files changed, 36 insertions, 41 deletions
diff --git a/lib/builtins/enable_execute_stack.c b/lib/builtins/enable_execute_stack.c index 327d460b4..e18de4eae 100644 --- a/lib/builtins/enable_execute_stack.c +++ b/lib/builtins/enable_execute_stack.c @@ -1,12 +1,10 @@ -/* ===-- enable_execute_stack.c - Implement __enable_execute_stack ---------=== - * - * The LLVM Compiler Infrastructure - * - * This file is dual licensed under the MIT and the University of Illinois Open - * Source Licenses. See LICENSE.TXT for details. - * - * ===----------------------------------------------------------------------=== - */ +//===-- enable_execute_stack.c - Implement __enable_execute_stack ---------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// #include "int_lib.h" @@ -14,10 +12,9 @@ #include <sys/mman.h> #endif -/* #include "config.h" - * FIXME: CMake - include when cmake system is ready. - * Remove #define HAVE_SYSCONF 1 line. - */ +// #include "config.h" +// FIXME: CMake - include when cmake system is ready. +// Remove #define HAVE_SYSCONF 1 line. #define HAVE_SYSCONF 1 #ifdef _WIN32 @@ -26,47 +23,45 @@ #else #ifndef __APPLE__ #include <unistd.h> -#endif /* __APPLE__ */ -#endif /* _WIN32 */ +#endif // __APPLE__ +#endif // _WIN32 #if __LP64__ - #define TRAMPOLINE_SIZE 48 +#define TRAMPOLINE_SIZE 48 #else - #define TRAMPOLINE_SIZE 40 +#define TRAMPOLINE_SIZE 40 #endif -/* - * The compiler generates calls to __enable_execute_stack() when creating - * trampoline functions on the stack for use with nested functions. - * It is expected to mark the page(s) containing the address - * and the next 48 bytes as executable. Since the stack is normally rw- - * that means changing the protection on those page(s) to rwx. - */ +// The compiler generates calls to __enable_execute_stack() when creating +// trampoline functions on the stack for use with nested functions. +// It is expected to mark the page(s) containing the address +// and the next 48 bytes as executable. Since the stack is normally rw- +// that means changing the protection on those page(s) to rwx. -COMPILER_RT_ABI void -__enable_execute_stack(void* addr) -{ +COMPILER_RT_ABI void __enable_execute_stack(void *addr) { #if _WIN32 - MEMORY_BASIC_INFORMATION mbi; - if (!VirtualQuery (addr, &mbi, sizeof(mbi))) - return; /* We should probably assert here because there is no return value */ - VirtualProtect (mbi.BaseAddress, mbi.RegionSize, PAGE_EXECUTE_READWRITE, &mbi.Protect); + MEMORY_BASIC_INFORMATION mbi; + if (!VirtualQuery(addr, &mbi, sizeof(mbi))) + return; // We should probably assert here because there is no return value + VirtualProtect(mbi.BaseAddress, mbi.RegionSize, PAGE_EXECUTE_READWRITE, + &mbi.Protect); #else #if __APPLE__ - /* On Darwin, pagesize is always 4096 bytes */ - const uintptr_t pageSize = 4096; + // On Darwin, pagesize is always 4096 bytes + const uintptr_t pageSize = 4096; #elif !defined(HAVE_SYSCONF) #error "HAVE_SYSCONF not defined! See enable_execute_stack.c" #else - const uintptr_t pageSize = sysconf(_SC_PAGESIZE); -#endif /* __APPLE__ */ + const uintptr_t pageSize = sysconf(_SC_PAGESIZE); +#endif // __APPLE__ - const uintptr_t pageAlignMask = ~(pageSize-1); - uintptr_t p = (uintptr_t)addr; - unsigned char* startPage = (unsigned char*)(p & pageAlignMask); - unsigned char* endPage = (unsigned char*)((p+TRAMPOLINE_SIZE+pageSize) & pageAlignMask); - size_t length = endPage - startPage; - (void) mprotect((void *)startPage, length, PROT_READ | PROT_WRITE | PROT_EXEC); + const uintptr_t pageAlignMask = ~(pageSize - 1); + uintptr_t p = (uintptr_t)addr; + unsigned char *startPage = (unsigned char *)(p & pageAlignMask); + unsigned char *endPage = + (unsigned char *)((p + TRAMPOLINE_SIZE + pageSize) & pageAlignMask); + size_t length = endPage - startPage; + (void)mprotect((void *)startPage, length, PROT_READ | PROT_WRITE | PROT_EXEC); #endif } |