Hi,
When I perform a full system rebuild with glibc-2.44 I notice m4-1.4.21
test suite cannot finish. Investigate shows the problem is a
posix_spawn_file_actions_addchdir_np infinitely recursively calling
itself. The root cause is:
- gnulib posix_spawn_faction_addchdir.m4 has:
AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_addchdir])
and:
if test $ac_cv_func_posix_spawn_file_actions_addchdir = yes; then
dnl This function is not yet standardized. Therefore override the
dnl system's implementation always.
REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR=1
else
HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR=0
fi
So it's checking the existence of posix_spawn_file_actions_addchdir w/o
including any headers.
- glibc-2.44 spawn.h has:
/* Add an action changing the directory to PATH during spawn. This
affects the subsequent file actions.
Alias of posix_spawn_file_actions_addchdir_np. */
extern int __REDIRECT_NTH (posix_spawn_file_actions_addchdir,
(posix_spawn_file_actions_t * __restrict __actions,
const char *__restrict __path),
posix_spawn_file_actions_addchdir_np);
This preprocess (with -D_GNU_SOURCE) to:
extern int posix_spawn_file_actions_addfchdir (
posix_spawn_file_actions_t *,
int __fd) __asm__ (""
"posix_spawn_file_actions_addfchdir_np")
__attribute__ ((__nothrow__, __leaf__));
;
I.e. libc.so.6 does not have posix_spawn_file_actions_addchdir symbol,
but this header magic makes GCC replace every occurrence of
posix_spawn_file_actions_addfchdir in the symtab with
posix_spawn_file_actions_addfchdir_np.
So AC_CHECK_FUNCS_ONCE([posix_spawn_file_actions_addchdir]) will return
"posix_spawn_file_actions_addchdir is NOT defined" and then
REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR will be NOT set.
- gnulib spawn_faction_addchdir.c has:
int
posix_spawn_file_actions_addchdir (posix_spawn_file_actions_t *file_actions,
const char *path)
#undef posix_spawn_file_actions_addchdir
{
#if !REPLACE_POSIX_SPAWN
return posix_spawn_file_actions_addchdir_np (file_actions, path);
#else
... ...
As REPLACE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR is not set,
posix_spawn_file_actions_addchdir is not defined to
rpl_posix_spawn_file_actions_addchdir.
So spawn_faction_addchdir.c ends up:
int
posix_spawn_file_actions_addchdir (posix_spawn_file_actions_t *file_actions,
const char *path)
{
return posix_spawn_file_actions_addchdir_np (file_actions, path);
}
and remember the symtab hack... this efficiently becomes:
int
posix_spawn_file_actions_addchdir_np (posix_spawn_file_actions_t *file_actions,
const char *path)
{
return posix_spawn_file_actions_addchdir_np (file_actions, path);
}
:-(
It can be worked around with
ac_cv_func_posix_spawn_file_actions_addchdir=yes (which basically tells
the configure system we have a posix_spawn_file_actions_addchdir, some
kind of a "fact" with glibc 2.44).
Thoughts on fix this?
--
Xi Ruoyao <[email protected]>
