367 lines
11 KiB
C
367 lines
11 KiB
C
/* pseudo-reloc.c
|
|
|
|
Contributed by Egor Duda <deo@logos-m.ru>
|
|
Modified by addition of runtime_pseudo_reloc version 2
|
|
by Kai Tietz <kai.tietz@onevision.com>
|
|
|
|
THIS SOFTWARE IS NOT COPYRIGHTED
|
|
|
|
This source code is offered for use in the public domain. You may
|
|
use, modify or distribute it freely.
|
|
|
|
This code is distributed in the hope that it will be useful but
|
|
WITHOUT ANY WARRANTY. ALL WARRENTIES, EXPRESS OR IMPLIED ARE HEREBY
|
|
DISCLAMED. This includes but is not limited to warrenties of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
|
*/
|
|
|
|
#include <windows.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <stdarg.h>
|
|
#include <memory.h>
|
|
|
|
#if defined(__CYGWIN__)
|
|
#include <wchar.h>
|
|
#include <ntdef.h>
|
|
#include <sys/cygwin.h>
|
|
/* copied from winsup.h */
|
|
# define NO_COPY __attribute__((nocommon)) __attribute__((section(".data_cygwin_nocopy")))
|
|
/* custom status code: */
|
|
#define STATUS_ILLEGAL_DLL_PSEUDO_RELOCATION ((NTSTATUS) 0xe0000269)
|
|
#define SHORT_MSG_BUF_SZ 128
|
|
#else
|
|
# define NO_COPY
|
|
#endif
|
|
|
|
#ifdef __GNUC__
|
|
#define ATTRIBUTE_NORETURN __attribute__ ((noreturn))
|
|
#else
|
|
#define ATTRIBUTE_NORETURN
|
|
#endif
|
|
|
|
#ifndef __MINGW_LSYMBOL
|
|
#define __MINGW_LSYMBOL(sym) sym
|
|
#endif
|
|
|
|
extern char __RUNTIME_PSEUDO_RELOC_LIST__;
|
|
extern char __RUNTIME_PSEUDO_RELOC_LIST_END__;
|
|
extern char __MINGW_LSYMBOL(_image_base__);
|
|
|
|
void _pei386_runtime_relocator (void);
|
|
|
|
/* v1 relocation is basically:
|
|
* *(base + .target) += .addend
|
|
* where (base + .target) is always assumed to point
|
|
* to a DWORD (4 bytes).
|
|
*/
|
|
typedef struct {
|
|
DWORD addend;
|
|
DWORD target;
|
|
} runtime_pseudo_reloc_item_v1;
|
|
|
|
/* v2 relocation is more complex. In effect, it is
|
|
* *(base + .target) += *(base + .sym) - (base + .sym)
|
|
* with care taken in both reading, sign extension, and writing
|
|
* because .flags may indicate that (base + .target) may point
|
|
* to a BYTE, WORD, DWORD, or QWORD (w64).
|
|
*/
|
|
typedef struct {
|
|
DWORD sym;
|
|
DWORD target;
|
|
DWORD flags;
|
|
} runtime_pseudo_reloc_item_v2;
|
|
|
|
typedef struct {
|
|
DWORD magic1;
|
|
DWORD magic2;
|
|
DWORD version;
|
|
} runtime_pseudo_reloc_v2;
|
|
|
|
static void ATTRIBUTE_NORETURN
|
|
__report_error (const char *msg, ...)
|
|
{
|
|
#ifdef __CYGWIN__
|
|
/* This function is used to print short error messages
|
|
* to stderr, which may occur during DLL initialization
|
|
* while fixing up 'pseudo' relocations. This early, we
|
|
* may not be able to use cygwin stdio functions, so we
|
|
* use the win32 WriteFile api. This should work with both
|
|
* normal win32 console IO handles, redirected ones, and
|
|
* cygwin ptys.
|
|
*/
|
|
char buf[SHORT_MSG_BUF_SZ];
|
|
wchar_t module[MAX_PATH];
|
|
char * posix_module = NULL;
|
|
static const char * UNKNOWN_MODULE = "<unknown module>: ";
|
|
static const char CYGWIN_FAILURE_MSG[] = "Cygwin runtime failure: ";
|
|
static const size_t CYGWIN_FAILURE_MSG_LEN = sizeof (CYGWIN_FAILURE_MSG) - 1;
|
|
DWORD len;
|
|
DWORD done;
|
|
va_list args;
|
|
HANDLE errh = GetStdHandle (STD_ERROR_HANDLE);
|
|
ssize_t modulelen = GetModuleFileNameW (NULL, module, sizeof (module));
|
|
|
|
if (errh == INVALID_HANDLE_VALUE)
|
|
cygwin_internal (CW_EXIT_PROCESS,
|
|
STATUS_ILLEGAL_DLL_PSEUDO_RELOCATION,
|
|
1);
|
|
|
|
if (modulelen > 0)
|
|
posix_module = cygwin_create_path (CCP_WIN_W_TO_POSIX, module);
|
|
|
|
va_start (args, msg);
|
|
len = (DWORD) vsnprintf (buf, SHORT_MSG_BUF_SZ, msg, args);
|
|
va_end (args);
|
|
buf[SHORT_MSG_BUF_SZ-1] = '\0'; /* paranoia */
|
|
|
|
if (posix_module)
|
|
{
|
|
WriteFile (errh, (PCVOID)CYGWIN_FAILURE_MSG,
|
|
CYGWIN_FAILURE_MSG_LEN, &done, NULL);
|
|
WriteFile (errh, (PCVOID)posix_module,
|
|
strlen(posix_module), &done, NULL);
|
|
WriteFile (errh, (PCVOID)": ", 2, &done, NULL);
|
|
WriteFile (errh, (PCVOID)buf, len, &done, NULL);
|
|
free (posix_module);
|
|
}
|
|
else
|
|
{
|
|
WriteFile (errh, (PCVOID)CYGWIN_FAILURE_MSG,
|
|
CYGWIN_FAILURE_MSG_LEN, &done, NULL);
|
|
WriteFile (errh, (PCVOID)UNKNOWN_MODULE,
|
|
sizeof(UNKNOWN_MODULE), &done, NULL);
|
|
WriteFile (errh, (PCVOID)buf, len, &done, NULL);
|
|
}
|
|
WriteFile (errh, (PCVOID)"\n", 1, &done, NULL);
|
|
|
|
cygwin_internal (CW_EXIT_PROCESS,
|
|
STATUS_ILLEGAL_DLL_PSEUDO_RELOCATION,
|
|
1);
|
|
/* not reached, but silences noreturn warning */
|
|
abort ();
|
|
#else
|
|
va_list argp;
|
|
va_start (argp, msg);
|
|
# ifdef __MINGW64_VERSION_MAJOR
|
|
fprintf (stderr, "Mingw-w64 runtime failure:\n");
|
|
# else
|
|
fprintf (stderr, "Mingw runtime failure:\n");
|
|
# endif
|
|
vfprintf (stderr, msg, argp);
|
|
va_end (argp);
|
|
abort ();
|
|
#endif
|
|
}
|
|
|
|
/* This function temporarily marks the page containing addr
|
|
* writable, before copying len bytes from *src to *addr, and
|
|
* then restores the original protection settings to the page.
|
|
*
|
|
* Using this function eliminates the requirement with older
|
|
* pseudo-reloc implementations, that sections containing
|
|
* pseudo-relocs (such as .text and .rdata) be permanently
|
|
* marked writable. This older behavior sabotaged any memory
|
|
* savings achieved by shared libraries on win32 -- and was
|
|
* slower, too. However, on cygwin as of binutils 2.20 the
|
|
* .text section is still marked writable, and the .rdata section
|
|
* is folded into the (writable) .data when --enable-auto-import.
|
|
*/
|
|
static void
|
|
__write_memory (void *addr, const void *src, size_t len)
|
|
{
|
|
MEMORY_BASIC_INFORMATION b;
|
|
DWORD oldprot;
|
|
|
|
if (!len)
|
|
return;
|
|
|
|
if (!VirtualQuery (addr, &b, sizeof(b)))
|
|
{
|
|
__report_error (" VirtualQuery failed for %d bytes at address %p",
|
|
(int) sizeof(b), addr);
|
|
}
|
|
|
|
/* Temporarily allow write access to read-only protected memory. */
|
|
if (b.Protect != PAGE_EXECUTE_READWRITE && b.Protect != PAGE_READWRITE)
|
|
VirtualProtect (b.BaseAddress, b.RegionSize, PAGE_EXECUTE_READWRITE,
|
|
&oldprot);
|
|
/* write the data. */
|
|
memcpy (addr, src, len);
|
|
/* Restore original protection. */
|
|
if (b.Protect != PAGE_EXECUTE_READWRITE && b.Protect != PAGE_READWRITE)
|
|
VirtualProtect (b.BaseAddress, b.RegionSize, oldprot, &oldprot);
|
|
}
|
|
|
|
#define RP_VERSION_V1 0
|
|
#define RP_VERSION_V2 1
|
|
|
|
static void
|
|
do_pseudo_reloc (void * start, void * end, void * base)
|
|
{
|
|
ptrdiff_t addr_imp, reldata;
|
|
ptrdiff_t reloc_target = (ptrdiff_t) ((char *)end - (char*)start);
|
|
runtime_pseudo_reloc_v2 *v2_hdr = (runtime_pseudo_reloc_v2 *) start;
|
|
runtime_pseudo_reloc_item_v2 *r;
|
|
|
|
/* A valid relocation list will contain at least one entry, and
|
|
* one v1 data structure (the smallest one) requires two DWORDs.
|
|
* So, if the relocation list is smaller than 8 bytes, bail.
|
|
*/
|
|
if (reloc_target < 8)
|
|
return;
|
|
|
|
/* Check if this is the old pseudo relocation version. */
|
|
/* There are two kinds of v1 relocation lists:
|
|
* 1) With a (v2-style) version header. In this case, the
|
|
* first entry in the list is a 3-DWORD structure, with
|
|
* value:
|
|
* { 0, 0, RP_VERSION_V1 }
|
|
* In this case, we skip to the next entry in the list,
|
|
* knowing that all elements after the head item can
|
|
* be cast to runtime_pseudo_reloc_item_v1.
|
|
* 2) Without a (v2-style) version header. In this case, the
|
|
* first element in the list IS an actual v1 relocation
|
|
* record, which is two DWORDs. Because there will never
|
|
* be a case where a v1 relocation record has both
|
|
* addend == 0 and target == 0, this case will not be
|
|
* confused with the prior one.
|
|
* All current binutils, when generating a v1 relocation list,
|
|
* use the second (e.g. original) form -- that is, without the
|
|
* v2-style version header.
|
|
*/
|
|
if (reloc_target >= 12
|
|
&& v2_hdr->magic1 == 0 && v2_hdr->magic2 == 0
|
|
&& v2_hdr->version == RP_VERSION_V1)
|
|
{
|
|
/* We have a list header item indicating that the rest
|
|
* of the list contains v1 entries. Move the pointer to
|
|
* the first true v1 relocation record. By definition,
|
|
* that v1 element will not have both addend == 0 and
|
|
* target == 0 (and thus, when interpreted as a
|
|
* runtime_pseudo_reloc_v2, it will not have both
|
|
* magic1 == 0 and magic2 == 0).
|
|
*/
|
|
v2_hdr++;
|
|
}
|
|
|
|
if (v2_hdr->magic1 != 0 || v2_hdr->magic2 != 0)
|
|
{
|
|
/*************************
|
|
* Handle v1 relocations *
|
|
*************************/
|
|
runtime_pseudo_reloc_item_v1 * o;
|
|
for (o = (runtime_pseudo_reloc_item_v1 *) v2_hdr;
|
|
o < (runtime_pseudo_reloc_item_v1 *)end;
|
|
o++)
|
|
{
|
|
DWORD newval;
|
|
reloc_target = (ptrdiff_t) base + o->target;
|
|
newval = (*((DWORD*) reloc_target)) + o->addend;
|
|
__write_memory ((void *) reloc_target, &newval, sizeof(DWORD));
|
|
}
|
|
return;
|
|
}
|
|
|
|
/* If we got this far, then we have relocations of version 2 or newer */
|
|
|
|
/* Check if this is a known version. */
|
|
if (v2_hdr->version != RP_VERSION_V2)
|
|
{
|
|
__report_error (" Unknown pseudo relocation protocol version %d.\n",
|
|
(int) v2_hdr->version);
|
|
return;
|
|
}
|
|
|
|
/*************************
|
|
* Handle v2 relocations *
|
|
*************************/
|
|
|
|
/* Walk over header. */
|
|
r = (runtime_pseudo_reloc_item_v2 *) &v2_hdr[1];
|
|
|
|
for (; r < (runtime_pseudo_reloc_item_v2 *) end; r++)
|
|
{
|
|
/* location where new address will be written */
|
|
reloc_target = (ptrdiff_t) base + r->target;
|
|
|
|
/* get sym pointer. It points either to the iat entry
|
|
* of the referenced element, or to the stub function.
|
|
*/
|
|
addr_imp = (ptrdiff_t) base + r->sym;
|
|
addr_imp = *((ptrdiff_t *) addr_imp);
|
|
|
|
/* read existing relocation value from image, casting to the
|
|
* bitsize indicated by the 8 LSBs of flags. If the value is
|
|
* negative, manually sign-extend to ptrdiff_t width. Raise an
|
|
* error if the bitsize indicated by the 8 LSBs of flags is not
|
|
* supported.
|
|
*/
|
|
switch ((r->flags & 0xff))
|
|
{
|
|
case 8:
|
|
reldata = (ptrdiff_t) (*((unsigned char *)reloc_target));
|
|
if ((reldata & 0x80) != 0)
|
|
reldata |= ~((ptrdiff_t) 0xff);
|
|
break;
|
|
case 16:
|
|
reldata = (ptrdiff_t) (*((unsigned short *)reloc_target));
|
|
if ((reldata & 0x8000) != 0)
|
|
reldata |= ~((ptrdiff_t) 0xffff);
|
|
break;
|
|
case 32:
|
|
reldata = (ptrdiff_t) (*((unsigned int *)reloc_target));
|
|
#ifdef _WIN64
|
|
if ((reldata & 0x80000000) != 0)
|
|
reldata |= ~((ptrdiff_t) 0xffffffff);
|
|
#endif
|
|
break;
|
|
#ifdef _WIN64
|
|
case 64:
|
|
reldata = (ptrdiff_t) (*((unsigned long long *)reloc_target));
|
|
break;
|
|
#endif
|
|
default:
|
|
reldata=0;
|
|
__report_error (" Unknown pseudo relocation bit size %d.\n",
|
|
(int) (r->flags & 0xff));
|
|
break;
|
|
}
|
|
|
|
/* Adjust the relocation value */
|
|
reldata -= ((ptrdiff_t) base + r->sym);
|
|
reldata += addr_imp;
|
|
|
|
/* Write the new relocation value back to *reloc_target */
|
|
switch ((r->flags & 0xff))
|
|
{
|
|
case 8:
|
|
__write_memory ((void *) reloc_target, &reldata, 1);
|
|
break;
|
|
case 16:
|
|
__write_memory ((void *) reloc_target, &reldata, 2);
|
|
break;
|
|
case 32:
|
|
__write_memory ((void *) reloc_target, &reldata, 4);
|
|
break;
|
|
#ifdef _WIN64
|
|
case 64:
|
|
__write_memory ((void *) reloc_target, &reldata, 8);
|
|
break;
|
|
#endif
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
_pei386_runtime_relocator (void)
|
|
{
|
|
static NO_COPY int was_init = 0;
|
|
if (was_init)
|
|
return;
|
|
++was_init;
|
|
do_pseudo_reloc (&__RUNTIME_PSEUDO_RELOC_LIST__,
|
|
&__RUNTIME_PSEUDO_RELOC_LIST_END__,
|
|
&__MINGW_LSYMBOL(_image_base__));
|
|
}
|