mirror of
https://github.com/alliedmodders/metamod-source.git
synced 2024-11-29 11:24:19 +01:00
341 lines
7.8 KiB
C++
341 lines
7.8 KiB
C++
/* ======== SourceHook ========
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* Copyright (C) 2004-2008 Metamod:Source Development Team
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* No warranties of any kind
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*
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* License: zlib/libpng
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*
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* Author(s): Pavol "PM OnoTo" Marko, Scott "Damaged Soul" Ehlert
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* Contributors: lancevorgin, XAD, theqizmo
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* ============================
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*/
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#ifndef __SHINT_MEMORY_H__
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#define __SHINT_MEMORY_H__
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// Feb 17 / 2005:
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// Unprotect now sets to readwrite
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// The vtable doesn't need to be executable anyway
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# if SH_XP == SH_XP_WINAPI
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# include <windows.h>
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# define SH_MEM_READ 1
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# define SH_MEM_WRITE 2
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# define SH_MEM_EXEC 4
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# elif SH_XP == SH_XP_POSIX
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# include <sys/mman.h>
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# include <stdio.h>
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# include <signal.h>
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# include <setjmp.h>
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# include <stdint.h>
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// http://www.die.net/doc/linux/man/man2/mprotect.2.html
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# include <limits.h>
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# ifndef PAGESIZE
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# define PAGESIZE 4096
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# endif
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# define SH_MEM_READ PROT_READ
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# define SH_MEM_WRITE PROT_WRITE
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# define SH_MEM_EXEC PROT_EXEC
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// We need to align addr down to pagesize on linux
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// We assume PAGESIZE is a power of two
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# define SH_LALIGN(x) (void*)((uintptr_t)(x) & ~(PAGESIZE-1))
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# define SH_LALDIF(x) ((uintptr_t)(x) & (PAGESIZE-1))
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# else
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# error Unsupported OS/Compiler
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# endif
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namespace SourceHook
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{
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static inline bool GetPageBits(void *addr, int *bits)
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{
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#if SH_SYS == SH_SYS_LINUX
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// On linux, first check /proc/self/maps
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unsigned long laddr = reinterpret_cast<unsigned long>(addr);
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FILE *pF = fopen("/proc/self/maps", "r");
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if (pF) {
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// Linux /proc/self/maps -> parse
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// Format:
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// lower upper prot stuff path
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// 08048000-0804c000 r-xp 00000000 03:03 1010107 /bin/cat
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unsigned long rlower, rupper;
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char r, w, x;
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while (fscanf(pF, "%lx-%lx %c%c%c", &rlower, &rupper, &r, &w, &x) != EOF) {
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// Check whether we're IN THERE!
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if (laddr >= rlower && laddr < rupper) {
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fclose(pF);
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*bits = 0;
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if (r == 'r')
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*bits |= SH_MEM_READ;
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if (w == 'w')
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*bits |= SH_MEM_WRITE;
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if (x == 'x')
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*bits |= SH_MEM_EXEC;
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return true;
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}
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// Read to end of line
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int c;
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while ((c = fgetc(pF)) != '\n') {
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if (c == EOF)
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break;
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}
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if (c == EOF)
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break;
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}
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fclose(pF);
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return false;
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}
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pF = fopen("/proc/curproc/map", "r");
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if (pF) {
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// FreeBSD /proc/curproc/map -> parse
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// 0x804800 0x805500 13 15 0xc6e18960 r-x 21 0x0 COW NC vnode
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unsigned long rlower, rupper, ignoreLong;
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int ignoreInt;
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char r, w, x;
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while (fscanf(pF, "0x%lx 0x%lx %d %d 0x%lx %c%c%c", &rlower, &rupper, &ignoreInt,
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&ignoreInt, &ignoreLong, &r, &w, &x) != EOF) {
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// Check whether we're IN THERE!
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if (laddr >= rlower && laddr < rupper) {
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fclose(pF);
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*bits = 0;
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if (r == 'r')
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*bits |= SH_MEM_READ;
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if (r == 'w')
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*bits |= SH_MEM_WRITE;
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if (r == 'x')
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*bits |= SH_MEM_EXEC;
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return true;
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}
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// Read to end of line
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int c;
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while ((c = fgetc(pF)) != '\n') {
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if (c == EOF)
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break;
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}
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if (c == EOF)
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break;
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}
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fclose(pF);
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return false;
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}
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return false;
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#elif SH_SYS == SH_SYS_APPLE
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#elif SH_XP == SH_XP_WINAPI
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SYSTEM_INFO info;
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GetSystemInfo(&info);
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MEMORY_BASIC_INFORMATION mem;
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size_t base = size_t(addr) & ~size_t(info.dwPageSize - 1);
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if (!VirtualQuery((void *)base, &mem, sizeof(mem)))
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return false;
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switch (mem.Protect) {
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case PAGE_EXECUTE:
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*bits = SH_MEM_EXEC;
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break;
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case PAGE_EXECUTE_READ:
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*bits = SH_MEM_EXEC | SH_MEM_READ;
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break;
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case PAGE_EXECUTE_READWRITE:
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case PAGE_EXECUTE_WRITECOPY:
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*bits = SH_MEM_EXEC | SH_MEM_READ | SH_MEM_WRITE;
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break;
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case PAGE_NOACCESS:
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*bits = 0;
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break;
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case PAGE_READONLY:
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*bits = SH_MEM_READ;
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break;
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case PAGE_READWRITE:
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case PAGE_WRITECOPY:
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*bits = SH_MEM_READ | SH_MEM_WRITE;
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break;
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default:
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return false;
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}
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return true;
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#endif
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}
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inline bool SetMemAccess(void *addr, size_t len, int access)
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{
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# if SH_XP == SH_XP_POSIX
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return mprotect(SH_LALIGN(addr), len + SH_LALDIF(addr), access)==0 ? true : false;
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# else
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DWORD tmp;
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DWORD prot;
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switch (access)
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{
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case SH_MEM_READ:
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prot = PAGE_READONLY; break;
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case SH_MEM_READ | SH_MEM_WRITE:
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prot = PAGE_READWRITE; break;
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case SH_MEM_READ | SH_MEM_EXEC:
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prot = PAGE_EXECUTE_READ; break;
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default:
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case SH_MEM_READ | SH_MEM_WRITE | SH_MEM_EXEC:
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prot = PAGE_EXECUTE_READWRITE; break;
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}
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return VirtualProtect(addr, len, prot, &tmp) ? true : false;
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# endif
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}
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inline bool MakePageWritable(void *addr)
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{
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int bits;
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if (GetPageBits(addr, &bits)) {
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if (bits & SH_MEM_WRITE)
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return true;
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bits |= SH_MEM_WRITE;
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} else {
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bits = SH_MEM_READ | SH_MEM_WRITE | SH_MEM_EXEC;
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}
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return SetMemAccess(addr, sizeof(void *), bits);
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}
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#if SH_XP == SH_XP_POSIX
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namespace
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{
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bool g_BadReadCalled;
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jmp_buf g_BadReadJmpBuf;
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# if SH_SYS == SH_SYS_LINUX
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static void BadReadHandler(int sig)
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{
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if (g_BadReadCalled)
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longjmp(g_BadReadJmpBuf, 1);
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}
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# elif SH_SYS == SH_SYS_APPLE
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static void BadReadHandler(int signal, siginfo_t* my_siginfo, void* my_context)
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{
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if (g_BadReadCalled)
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longjmp(g_BadReadJmpBuf, 1);
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}
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# endif
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}
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#endif
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/**
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* @brief Checks whether the specified memory region is (still) accessible
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*
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* @param addr The lower boundary
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* @param len Length of the region to be checked
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*/
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namespace
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{
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bool ModuleInMemory(char *addr, size_t len)
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{
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#if SH_SYS == SH_SYS_LINUX
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// On linux, first check /proc/self/maps
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long lower = reinterpret_cast<long>(addr);
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long upper = lower + len;
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FILE *pF = fopen("/proc/self/maps", "r");
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if (pF)
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{
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// Linux /proc/self/maps -> parse
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// Format:
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// lower upper prot stuff path
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// 08048000-0804c000 r-xp 00000000 03:03 1010107 /bin/cat
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long rlower, rupper;
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while (fscanf(pF, "%lx-%lx", &rlower, &rupper) != EOF)
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{
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// Check whether we're IN THERE!
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if (lower >= rlower && upper <= rupper)
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{
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fclose(pF);
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return true;
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}
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// Read to end of line
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int c;
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while ((c = fgetc(pF)) != '\n')
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{
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if (c == EOF)
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break;
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}
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if (c == EOF)
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break;
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}
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fclose(pF);
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return false;
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}
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pF = fopen("/proc/curproc/map", "r");
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if (pF)
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{
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// FreeBSD /proc/curproc/map -> parse
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// 0x804800 0x805500 13 15 0xc6e18960 r-x 21 0x0 COW NC vnode
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long rlower, rupper;
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while (fscanf(pF, "0x%lx 0x%lx", &rlower, &rupper) != EOF)
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{
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// Check whether we're IN THERE!
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if (lower >= rlower && upper <= rupper)
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{
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fclose(pF);
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return true;
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}
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// Read to end of line
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int c;
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while ((c = fgetc(pF)) != '\n')
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{
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if (c == EOF)
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break;
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}
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if (c == EOF)
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break;
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}
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fclose(pF);
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return false;
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}
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// Both of the above failed, try to actually read and trap sigsegv (implemented by Damaged Soul)
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void(*prevHandler)(int sig);
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g_BadReadCalled = true;
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if (setjmp(g_BadReadJmpBuf))
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return true;
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prevHandler = signal(SIGSEGV, BadReadHandler);
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volatile const char *p = reinterpret_cast<const char*>(addr);
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char dummy;
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for (size_t i = 0; i < len; i++)
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dummy = p[i];
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g_BadReadCalled = false;
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signal(SIGSEGV, prevHandler);
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return false;
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#elif SH_SYS == SH_SYS_APPLE
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struct sigaction sa, osa;
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sa.sa_sigaction = BadReadHandler;
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sa.sa_flags = SA_SIGINFO | SA_RESTART;
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g_BadReadCalled = true;
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if (setjmp(g_BadReadJmpBuf))
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return false;
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if (sigaction(SIGBUS, &sa, &osa) == -1)
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return false;
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volatile const char *p = reinterpret_cast<const char *>(addr);
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char dummy;
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for (size_t i = 0; i < len; i++)
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dummy = p[i];
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g_BadReadCalled = false;
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return true;
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#elif SH_XP == SH_XP_WINAPI
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// On Win32, simply use IsBadReadPtr
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return !IsBadReadPtr(addr, len);
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#endif
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}
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}
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}
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#endif
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