ld.so symbols to be overriden by libc need to be extern to really get
overriden. __access happens to have never been exposed, putting it to
GLIBC_PRIVATE.
The function maybe_enable_malloc_check, which is called by
__tunables_init, calls __access_noerrno. It isn't problem when
symbol is is in ld.so, which has a special version of __access_noerrno
without stack protector. But when glibc is built with stack protector,
maybe_enable_malloc_check in libc.a can't call the regular version of
__access_noerrno with stack protector.
This patch changes how Linux defines the __access_noerrno to be an
inline call instead and thus preventing defining different build
rules for ld/static and shared.
H.J. Lu <hongjiu.lu@intel.com>
Adhemerval Zanella <adhemerval.zanella@linaro.org>
[BZ #21744]
* elf/dl-tunables.c: Include not-errno.h header.
* include/unistd.h (__access_noerrno): Remove definition.
* sysdeps/unix/sysv/linux/access.c (__access_noerrno): Likewise.
* sysdeps/generic/not-errno.h: New file.
* sysdeps/unix/sysv/linux/not-errno.h: Likewise.
Implement an internal version of __access called __access_noerrno that
avoids setting errno. This is useful to check accessibility of files
very early on in process startup i.e. before TLS setup. This allows
tunables to replace MALLOC_CHECK_ safely (i.e. check existence of
/etc/suid-debug to enable/disable MALLOC_CHECK) and at the same time
initialize very early so that it can override IFUNCs.
Checked on x86_64.
* hurd/hurd.h (__hurd_fail_noerrno): New function.
* include/unistd.h [IS_IN (rtld) || !defined SHARED]: Declare
__access_noerrno.
* io/access.c (__access_noerrno): New function.
* sysdeps/mach/hurd/access.c (hurd_fail_seterrno): New function.
(hurd_fail_seterrno): Likewise.
(access_common): Likewise.
(__access_noerrno): Likewise.
* sysdeps/nacl/access.c (__access_noerrno): Likewise.
* sysdeps/unix/sysv/linux/access.c (__access_noerrno): Likewise.
* sysdeps/nacl/nacl-interfaces.h (NACL_CALL_NOERRNO): New
macro.
This patch consolidates the Linux access implementation on
sysdeps/unix/sysv/linux/access.c. Similar to auto-generation through
syscalls.list, __NR_access is check and __NR_faccessat is used only
for newer architectures (where __NR_access is not defined).
Checked on x86_64.
* sysdeps/unix/sysv/linux/access.c: New file.
* sysdeps/unix/sysv/linux/generic/access.c: Remove file.
