/* pseudo-reloc.c
- Written by Egor Duda <deo@logos-m.ru>
+ 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
*/
#include <windows.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#if defined(__CYGWIN__)
+#include <wchar.h>
+#include <ntdef.h>
+#include <stdarg.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)
+#else
+# define NO_COPY
+#endif
extern char __RUNTIME_PSEUDO_RELOC_LIST__;
extern char __RUNTIME_PSEUDO_RELOC_LIST_END__;
extern char _image_base__;
-typedef struct
- {
- DWORD addend;
- DWORD target;
- }
-runtime_pseudo_reloc;
+/* 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;
-void
-do_pseudo_reloc (void* start, void* end, void* base)
+/* 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;
+
+#if defined(__CYGWIN__)
+#define SHORT_MSG_BUF_SZ 128
+/* 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.
+ */
+static BOOL
+__print_reloc_error (const char *fmt, ...)
{
- DWORD reloc_target;
- runtime_pseudo_reloc* r;
- for (r = (runtime_pseudo_reloc*) start; r < (runtime_pseudo_reloc*) end; r++)
+ char buf[SHORT_MSG_BUF_SZ];
+ wchar_t module[MAX_PATH];
+ char * posix_module = NULL;
+ BOOL rVal = FALSE;
+ static const char * UNKNOWN_MODULE = "<unknown module>: ";
+ 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)
+ return FALSE;
+
+ if (modulelen > 0)
+ posix_module = cygwin_create_path (CCP_WIN_W_TO_POSIX, module);
+
+ va_start (args, fmt);
+ len = (DWORD) vsnprintf (buf, SHORT_MSG_BUF_SZ, fmt, args);
+ va_end (args);
+ buf[SHORT_MSG_BUF_SZ-1] = '\0'; /* paranoia */
+
+ if (posix_module)
{
- reloc_target = (DWORD) base + r->target;
- *((DWORD*) reloc_target) += r->addend;
+ rVal = 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
+ {
+ rVal = WriteFile (errh, (PCVOID)UNKNOWN_MODULE,
+ sizeof(UNKNOWN_MODULE), &done, NULL) &&
+ WriteFile (errh, (PCVOID)buf, len, &done, NULL);
+ }
+ return rVal;
}
+#endif /* __CYGWIN__ */
+
+/* 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;
+ SIZE_T memsz;
+
+ if (!len)
+ return;
+
+ memsz = VirtualQuery (addr, &b, sizeof(b));
+
+#if defined(__CYGWIN__)
+ /* CYGWIN: If error, print error message and die. */
+ if (memsz == 0)
+ {
+ __print_reloc_error (
+ "error while loading shared libraries: bad address specified 0x%08x.\n",
+ addr);
+ cygwin_internal (CW_EXIT_PROCESS,
+ STATUS_ILLEGAL_DLL_PSEUDO_RELOCATION,
+ 1);
+ }
+#else
+ /* MINGW: If error, die. assert() may print error message when !NDEBUG */
+ assert (memsz);
+#endif
+
+ /* 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)
+ {
+#if defined(__CYGWIN__)
+ /* CYGWIN: Print error message and die, even when !DEBUGGING */
+ __print_reloc_error (
+ "error while loading shared libraries: invalid pseudo_reloc version %d.\n",
+ (int) v2_hdr->version);
+ cygwin_internal (CW_EXIT_PROCESS,
+ STATUS_ILLEGAL_DLL_PSEUDO_RELOCATION,
+ 1);
+#else
+# if defined(DEBUG)
+ /* MINGW: Don't die; just return to caller. If DEBUG, print error message. */
+ fprintf (stderr, "internal mingw runtime error:"
+ "psuedo_reloc version %d is unknown to this runtime.\n",
+ (int) v2_hdr->version);
+# endif
+#endif
+ 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;
+#if defined(__CYGWIN__)
+ /* Print error message and die, even when !DEBUGGING */
+ __print_reloc_error (
+ "error while loading shared libraries: unknown pseudo_reloc bit size %d.\n",
+ (int) (r->flags & 0xff));
+ cygwin_internal (CW_EXIT_PROCESS,
+ STATUS_ILLEGAL_DLL_PSEUDO_RELOCATION,
+ 1);
+#else
+# ifdef DEBUG
+ /* MINGW: If error, don't die; just print message if DEBUG */
+ fprintf(stderr, "internal mingw runtime error: "
+ "unknown pseudo_reloc bit size %d\n",
+ (int) (r->flags & 0xff));
+# endif
+#endif
+ 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 ()
{
+ 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__,
&_image_base__);
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