linux-user: Use public sigev_notify_thread_id member if available

_sigev_un._tid is an internal glibc field and is not available on
musl libc. The sigevent(7) man page and Linux UAPI headers both use
sigev_notify_thread_id as a public way to access this field.

musl libc supports this field since 1.2.2[0], and glibc plans to
add support as well[1][2].

If sigev_notify_thread_id is not available, fall back to _sigev_un._tid
as before.

[0] http://git.musl-libc.org/cgit/musl/commit/?id=7c71792e87691451f2a6b76348e83ad1889f1dcb
[1] https://www.openwall.com/lists/musl/2019/08/01/5
[2] https://sourceware.org/bugzilla/show_bug.cgi?id=27417

Signed-off-by: Michael Forney <mforney@mforney.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20210526035556.7931-1-mforney@mforney.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
master
Michael Forney 2021-05-25 20:55:56 -07:00 committed by Laurent Vivier
parent febf6fade6
commit 96ff758c6e
2 changed files with 21 additions and 1 deletions

16
configure vendored
View File

@ -4440,6 +4440,19 @@ if compile_prog "" "" ; then
st_atim=yes
fi
##########################################
# check if we have sigev_notify_thread_id
sigev_notify_thread_id=no
cat > $TMPC << EOF
#include <stddef.h>
#include <signal.h>
int main(void) { return offsetof(struct sigevent, sigev_notify_thread_id); }
EOF
if compile_prog "" "" ; then
sigev_notify_thread_id=yes
fi
##########################################
# check if trace backend exists
@ -5692,6 +5705,9 @@ fi
if test "$st_atim" = "yes" ; then
echo "HAVE_STRUCT_STAT_ST_ATIM=y" >> $config_host_mak
fi
if test "$sigev_notify_thread_id" = "yes" ; then
echo "HAVE_SIGEV_NOTIFY_THREAD_ID=y" >> $config_host_mak
fi
if test "$byteswap_h" = "yes" ; then
echo "CONFIG_BYTESWAP_H=y" >> $config_host_mak
fi

View File

@ -7405,6 +7405,10 @@ static inline abi_long host_to_target_timex64(abi_long target_addr,
}
#endif
#ifndef HAVE_SIGEV_NOTIFY_THREAD_ID
#define sigev_notify_thread_id _sigev_un._tid
#endif
static inline abi_long target_to_host_sigevent(struct sigevent *host_sevp,
abi_ulong target_addr)
{
@ -7425,7 +7429,7 @@ static inline abi_long target_to_host_sigevent(struct sigevent *host_sevp,
host_sevp->sigev_signo =
target_to_host_signal(tswap32(target_sevp->sigev_signo));
host_sevp->sigev_notify = tswap32(target_sevp->sigev_notify);
host_sevp->_sigev_un._tid = tswap32(target_sevp->_sigev_un._tid);
host_sevp->sigev_notify_thread_id = tswap32(target_sevp->_sigev_un._tid);
unlock_user_struct(target_sevp, target_addr, 1);
return 0;