This patch uses posix_spawn on system implementation. On Linux this has
the advantage of much lower memory consumption (usually 32 Kb minimum for
the mmap stack area).
Although POSIX does not require, glibc system implementation aims to be
thread and cancellation safe. The cancellation code is moved to generic
implementation and enabled iff SIGCANCEL is defined (similar on how the
cancellation handler is enabled on nptl-init.c).
Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
arm-linux-gnueabihf, and powerpc64le-linux-gnu.
* sysdeps/unix/sysv/linux/spawni.c (__spawni_child): Use
__sigismember instead of sigismember.
* sysdeps/posix/system.c [SIGCANCEL] (cancel_handler_args,
cancel_handler): New definitions.
(CLEANUP_HANDLER, CLEANUP_RESET): Likewise.
(DO_LOCK, DO_UNLOCK, INIT_LOCK, ADD_REF, SUB_REF): Remove.
(do_system): Use posix_spawn instead of fork and execl and remove
reentracy code.
* sysdeps/generic/not-errno.h (__kill_noerrno): New prototype.
* sysdeps/unix/sysv/linux/not-errno.h (__kill_noerrno): Likewise.
* sysdeps/unix/sysv/linux/ia64/system.c: Remove file.
* sysdeps/unix/sysv/linux/s390/system.c: Likewise.
* sysdeps/unix/sysv/linux/sparc/system.c: Likewise.
* sysdeps/unix/sysv/linux/system.c: Likewise.
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.
