stat() returning EFAULT?

[Sjors Gielen <mailinglist at dazjorz dot com>]

Hey all,

I noticed this weird cygwinism and wrote a little test case. It seems 
stat() is returning EFAULT on some of my files. I've done some digging 
through Cygwin source but couldn't see the source of the problem.

The testcase is a simple test.c which is compiled to test.exe. After 
that, it does a stat("test") and a stat("test.exe"). It doesn't matter 
if it runs stat on itself or on a different binary, so I chose to keep 
things simple.

Here's the test case and output:

#include <errno.h>
int main() {
	if(stat("test") != 0) perror("Calling stat() on test");
	if(stat("test.exe") != 0) perror("Calling stat() on test.exe");
	return 0;
}
// Calling stat() on test: Bad address
// Calling stat() on test.exe: Bad address

As far as I could see, the strace wasn't very informative. I've attached 
the relevant parts.

This is Cygwin from the current bleeding-edge CVS. Could anybody explain 
why stat() is returning -1 with errno set to EFAULT?

Sjors
// stat("test")

   27   36374 [main] test 2236 dll_crt0_1: user_data->main 0x401050
   23   36397 [main] test 2236 __set_errno: void dll_crt0_1(void*):908 val 0
   62   36459 [main] test 2236 stat64: entering
   26   36485 [main] test 2236 normalize_posix_path: src test
   24   36509 [main] test 2236 cwdstuff::get: posix /home/Sjors/tests/statefault
   22   36531 [main] test 2236 cwdstuff::get: (/home/Sjors/tests/statefault) = cwdstuff::get (0xC90008, 32768, 1, 0), errno 0
   24   36555 [main] test 2236 normalize_posix_path: /home/Sjors/tests/statefault/test = normalize_posix_path (test)
   22   36577 [main] test 2236 mount_info::conv_to_win32_path: conv_to_win32_path (/home/Sjors/tests/statefault/test)
   24   36601 [main] test 2236 set_flags: flags: binary (0x2)
   22   36623 [main] test 2236 mount_info::conv_to_win32_path: src_path /home/Sjors/tests/statefault/test, dst E:\overig\cygwin\root\home\Sjors\tests\statefault\test, flags 0xA, rc 0
   43   36666 [main] test 2236 symlink_info::check: 0xC0000034 = NtQueryInformationFile (\??\E:\overig\cygwin\root\home\Sjors\tests\statefault\test)
   46   36712 [main] test 2236 symlink_info::check: not a symlink
   33   36745 [main] test 2236 symlink_info::check: 0 = symlink.check (E:\overig\cygwin\root\home\Sjors\tests\statefault\test.exe, 0x223BA0) (0xA)
   25   36770 [main] test 2236 path_conv::check: this->path(E:\overig\cygwin\root\home\Sjors\tests\statefault\test.exe), has_acls(1)
   41   36811 [main] test 2236 build_fh_pc: fh 0x6123C564
   26   36837 [main] test 2236 stat_worker: (\??\E:\overig\cygwin\root\home\Sjors\tests\statefault\test.exe, 0x57, 0x6123C564), file_attributes 544
--- Process 2236, exception C0000005 at 611046AC
   80   36917 [main] test 2236 _cygtls::handle_exceptions: In cygwin_except_handler exc 0xC0000005 at 0x611046AC sp 0x224AD4
   25   36942 [main] test 2236 _cygtls::handle_exceptions: In cygwin_except_handler sig 11 at 0x611046AC
   28   36970 [main] test 2236 _cygtls::handle_exceptions: In cygwin_except_handler calling 0x0
   23   36993 [main] test 2236 __set_errno: void _cygtls::return_from_fault():259 val 14
   23   37016 [main] test 2236 stat_worker: -1 = (\??\E:\overig\cygwin\root\home\Sjors\tests\statefault\test.exe, 0x57)

// perror("Calling stat() on test")

   75   37091 [main] test 2236 fhandler_base::write: binary write
calling stat() on test  101   37192 [main] test 2236 fhandler_base::write: binary write
:    95   37287 [main] test 2236 fhandler_base::write: binary write
Bad address  134   37421 [main] test 2236 fhandler_base::write: binary write

// stat("test.exe")

   94   37515 [main] test 2236 stat64: entering
   23   37538 [main] test 2236 normalize_posix_path: src test.exe
   22   37560 [main] test 2236 cwdstuff::get: posix /home/Sjors/tests/statefault
   22   37582 [main] test 2236 cwdstuff::get: (/home/Sjors/tests/statefault) = cwdstuff::get (0xC90008, 32768, 1, 0), errno 14
   24   37606 [main] test 2236 normalize_posix_path: /home/Sjors/tests/statefault/test.exe = normalize_posix_path (test.exe)
   23   37629 [main] test 2236 mount_info::conv_to_win32_path: conv_to_win32_path (/home/Sjors/tests/statefault/test.exe)
   22   37651 [main] test 2236 set_flags: flags: binary (0x2)
   23   37674 [main] test 2236 mount_info::conv_to_win32_path: src_path /home/Sjors/tests/statefault/test.exe, dst E:\overig\cygwin\root\home\Sjors\tests\statefault\test.exe, flags 0xA, rc 0
   45   37719 [main] test 2236 symlink_info::check: not a symlink
   32   37751 [main] test 2236 symlink_info::check: 0 = symlink.check (E:\overig\cygwin\root\home\Sjors\tests\statefault\test.exe, 0x223BA0) (0xA)
   25   37776 [main] test 2236 path_conv::check: this->path(E:\overig\cygwin\root\home\Sjors\tests\statefault\test.exe), has_acls(1)
   40   37816 [main] test 2236 build_fh_pc: fh 0x6124C674
   24   37840 [main] test 2236 stat_worker: (\??\E:\overig\cygwin\root\home\Sjors\tests\statefault\test.exe, 0x57, 0x6124C674), file_attributes 544
--- Process 2236, exception C0000005 at 611046AC
   85   37925 [main] test 2236 _cygtls::handle_exceptions: In cygwin_except_handler exc 0xC0000005 at 0x611046AC sp 0x224AD4
   25   37950 [main] test 2236 _cygtls::handle_exceptions: In cygwin_except_handler sig 11 at 0x611046AC
   23   37973 [main] test 2236 _cygtls::handle_exceptions: In cygwin_except_handler calling 0x0
   23   37996 [main] test 2236 __set_errno: void _cygtls::return_from_fault():259 val 14
   23   38019 [main] test 2236 stat_worker: -1 = (\??\E:\overig\cygwin\root\home\Sjors\tests\statefault\test.exe, 0x57)

// perror("Calling stat() on test.exe");

   58   38077 [main] test 2236 fhandler_base::write: binary write
calling stat() on test.exe   96   38173 [main] test 2236 fhandler_base::write: binary write
:    95   38268 [main] test 2236 fhandler_base::write: binary write
Bad address  126   38394 [main] test 2236 fhandler_base::write: binary write

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