[A mod for Fallout: New Vegas relies on rewind not modifying the first argument passed to it.](https://github.com/jazzisparis/UIO-User-Interface-Organizer/blob/426d96391f9...) Since it only links to api-ms-win-crt-stdio I've kept the thunk usage to just ucrtbase.
-- v6: msvcrt, ucrtbase: Introduce rewind_preserve_stack.
From: Victor Chiletto v@hnn.net.br
This is a small thunk to rewind that preserves the first argument passed. This is needed because on some versions of GCC, rewind's call to _unlock_file is tail-call optimized, which modifies the stack. --- dlls/msvcrt/file.c | 17 ++++++++++++++ dlls/ucrtbase/tests/misc.c | 44 +++++++++++++++++++++++++++++++++++++ dlls/ucrtbase/ucrtbase.spec | 3 ++- 3 files changed, 63 insertions(+), 1 deletion(-)
diff --git a/dlls/msvcrt/file.c b/dlls/msvcrt/file.c index 58a607e3bbe..d1b78e707eb 100644 --- a/dlls/msvcrt/file.c +++ b/dlls/msvcrt/file.c @@ -45,6 +45,10 @@
#include "wine/debug.h"
+#if defined(__i386__) +#include "wine/asm.h" +#endif + WINE_DEFAULT_DEBUG_CHANNEL(msvcrt);
#undef _fstat @@ -1658,6 +1662,19 @@ int CDECL clearerr_s(FILE* file) return 0; }
+#if defined(__i386__) +/* Stack preserving thunk for rewind + * needed for the UIO mod for Fallout: New Vegas + */ +__ASM_GLOBAL_FUNC(rewind_preserve_stack, + "pushl 4(%esp)\n\t" + __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t") + "call "__ASM_NAME("rewind") "\n\t" + "addl $4,%esp\n\t" + __ASM_CFI(".cfi_adjust_cfa_offset -4\n\t") + "ret") +#endif + /********************************************************************* * rewind (MSVCRT.@) */ diff --git a/dlls/ucrtbase/tests/misc.c b/dlls/ucrtbase/tests/misc.c index 069de0787b7..86cdec88108 100644 --- a/dlls/ucrtbase/tests/misc.c +++ b/dlls/ucrtbase/tests/misc.c @@ -1591,6 +1591,47 @@ static void test_fopen_exclusive( void ) unlink(path); }
+#if defined(__i386__) +#include "pshpack1.h" +struct rewind_thunk { + BYTE push_esp[4]; /* push [esp+0x4] */ + BYTE call_rewind; /* call */ + DWORD rewind_addr; /* relative addr of rewind */ + BYTE pop_eax; /* pop eax */ + BYTE ret; /* ret */ +}; +#include "poppack.h" + +static FILE * (CDECL *test_rewind_wrapper)(FILE *fp); + +static void test_rewind_i386_abi(void) +{ + FILE *fp_in, *fp_out; + + struct rewind_thunk *thunk = VirtualAlloc(NULL, sizeof(*thunk), MEM_COMMIT, PAGE_EXECUTE_READWRITE); + + thunk->push_esp[0] = 0xff; + thunk->push_esp[1] = 0x74; + thunk->push_esp[2] = 0x24; + thunk->push_esp[3] = 0x04; + + thunk->call_rewind = 0xe8; + thunk->rewind_addr = (BYTE *) rewind - (BYTE *) (&thunk->rewind_addr + 1); + + thunk->pop_eax = 0x58; + thunk->ret = 0xc3; + + test_rewind_wrapper = (void *) thunk; + + fp_in = fopen("rewind_abi.tst", "wb"); + fp_out = test_rewind_wrapper(fp_in); + ok(fp_in == fp_out, "rewind modified the first argument in the stack\n"); + + fclose(fp_in); + unlink("rewind_abi.tst"); +} +#endif + START_TEST(misc) { int arg_c; @@ -1633,4 +1674,7 @@ START_TEST(misc) test_thread_storage(); test_fenv(); test_fopen_exclusive(); +#if defined(__i386__) + test_rewind_i386_abi(); +#endif } diff --git a/dlls/ucrtbase/ucrtbase.spec b/dlls/ucrtbase/ucrtbase.spec index bb505b42afb..3d4ea0d93d3 100644 --- a/dlls/ucrtbase/ucrtbase.spec +++ b/dlls/ucrtbase/ucrtbase.spec @@ -2470,7 +2470,8 @@ @ cdecl remquof(float float ptr) @ cdecl remquol(double double ptr) remquo @ cdecl rename(str str) -@ cdecl rewind(ptr) +@ cdecl -arch=i386 rewind(ptr) rewind_preserve_stack +@ cdecl -arch=!i386 rewind(ptr) @ cdecl rint(double) MSVCRT_rint @ cdecl rintf(float) @ cdecl rintl(double) MSVCRT_rint
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Victor Chiletto -
Victor Hermann Chiletto (＠vitorhnn)