Stephen Smalley <sds@xxxxxxxxxxxxx> writes:
On 3/11/19 11:00 AM, Petr Lautrbach wrote:
Since version 2.30 glibc implements gettid() system call
wrapper, see
https://sourceware.org/bugzilla/show_bug.cgi?id=6399
Fixes:
cc -O2 -g -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
-fstack-protector-strong -grecord-gcc-switches
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64
-mtune=generic -fasynchronous-unwind-tables
-fstack-clash-protection -fcf-protection -I../include
-D_GNU_SOURCE -DNO_ANDROID_BACKEND -c -o procattr.o
procattr.c
procattr.c:28:14: error: static declaration of ‘gettid’ follows
non-static declaration
28 | static pid_t gettid(void)
| ^~~~~~
In file included from /usr/include/unistd.h:1170,
from procattr.c:2:
/usr/include/bits/unistd_ext.h:34:16: note: previous
declaration of ‘gettid’ was here
34 | extern __pid_t gettid (void) __THROW;
| ^~~~~~
Signed-off-by: Petr Lautrbach <plautrba@xxxxxxxxxx>
I assume the glibc change will break a lot of software out there
that assumed
that "never" meant "never" and rolled their own gettid()
wrapper. Would have
been nice if they had at least added some #define to indicate
that it is now
provided for easy testing rather than needing to test minor
version number.
Anyway, regardless,
I asked for an advice from glibc Fedora maintainer [1] as the
current
version is Fedora Rawhide is still 2.29 but it already ships
gettid
wrapped linked as gettid@@GLIBC_2.30. The response was that I
should
rename libselinux gettid() to something else in order to prevent
such
conflict. It would mean that libselinux won't depend on glibc
implementation. But I decided to test the minor version and use
the new glibc wrapper when it's possible.
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1685594
Acked-by: Stephen Smalley <sds@xxxxxxxxxxxxx>
---
libselinux/src/procattr.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/libselinux/src/procattr.c
b/libselinux/src/procattr.c
index 48dd8aff..c6799ef2 100644
--- a/libselinux/src/procattr.c
+++ b/libselinux/src/procattr.c
@@ -22,8 +22,19 @@ static pthread_key_t destructor_key;
static int destructor_key_initialized = 0;
static __thread char destructor_initialized;
-#ifndef __BIONIC__
-/* Bionic declares this in unistd.h and has a definition for
it */
+/* Bionic and glibc >= 2.30 declare gettid() system call
wrapper in unistd.h and
+ * has a definition for it */
+#ifdef __BIONIC__
+ #define OVERRIDE_GETTID 0
+#elif !defined(__GLIBC_PREREQ)
+ #define OVERRIDE_GETTID 1
+#elif !__GLIBC_PREREQ(2,30)
+ #define OVERRIDE_GETTID 1
+#else
+ #define OVERRIDE_GETTID 0
+#endif
+
+#if OVERRIDE_GETTID
static pid_t gettid(void)
{
return syscall(__NR_gettid);
