Discussion:
[PATCH] Linux: Add gettid system call wrapper [BZ #6399]
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Florian Weimer
2018-12-05 10:53:15 UTC
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This commit adds gettid to <unistd.h> on Linux, and not to the
kernel-independent GNU API.

2018-12-05 Florian Weimer <***@redhat.com>

[BZ #6399]
Linux: Add gettid system call wrapper.
* posix/Makefile (headers): Add bits/unistd_ext.h.
* posix/bits/unistd_ext.h: New file.
* posix/unistd.h: Include it.
* sysdeps/unix/sysv/linux/Makefile [subdir == misc] (tests): Add
tst-gettid.
(tst-gettid): Link with $(shared-thread-library).
* sysdeps/unix/sysv/linux/Version (GLIBC_2.29): Export gettid.
* sysdeps/unix/sysv/linux/bits/unistd_ext.h: New file.
* sysdeps/unix/sysv/linux/bits/syscalls.list (gettid): Add.
* sysdeps/unix/sysv/linux/bits/tst-gettid.c: New file.
* sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.29):
Add gettid.
* sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/arm/libc.abilist (GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/hppa/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/i386/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/ia64/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/microblaze/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
(GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
(GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
(GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
(GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/nios2/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
(GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
(GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
(GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
(GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/sh/libc.abilist (GLIBC_2.29): Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist (GLIBC_2.29):
Likewise.
* sysdeps/unix/sysv/linux/tst-setgetname.c (gettid): Remove.

diff --git a/posix/Makefile b/posix/Makefile
index a8fb1e1839..49d7a91b77 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -31,7 +31,8 @@ headers := sys/utsname.h sys/times.h sys/wait.h sys/types.h unistd.h \
bits/local_lim.h tar.h bits/utsname.h bits/confname.h \
bits/waitflags.h bits/waitstatus.h sys/unistd.h sched.h \
bits/sched.h bits/cpu-set.h re_comp.h wait.h bits/environments.h \
- cpio.h spawn.h bits/unistd.h bits/types/struct_sched_param.h
+ cpio.h spawn.h bits/unistd.h bits/types/struct_sched_param.h \
+ bits/unistd_ext.h

routines := \
uname \
diff --git a/posix/bits/unistd_ext.h b/posix/bits/unistd_ext.h
new file mode 100644
index 0000000000..8019cfa758
--- /dev/null
+++ b/posix/bits/unistd_ext.h
@@ -0,0 +1,21 @@
+/* System-specific extensions of <unistd.h>, generic version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _UNISTD_H
+# error "Never include <bits/unistd_ext.h> directly; use <unistd.h> instead."
+#endif
diff --git a/posix/unistd.h b/posix/unistd.h
index a8cf28b5e7..127ed494ce 100644
--- a/posix/unistd.h
+++ b/posix/unistd.h
@@ -1166,6 +1166,9 @@ int getentropy (void *__buffer, size_t __length) __wur;
# include <bits/unistd.h>
#endif

+/* System-specific extensions. */
+#include <bits/unistd_ext.h>
+
__END_DECLS

#endif /* unistd.h */
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 362cf3b950..99884799e6 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -48,7 +48,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \
tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \
test-errno-linux tst-memfd_create tst-mlock2 tst-pkey \
- tst-rlimit-infinity tst-ofdlocks
+ tst-rlimit-infinity tst-ofdlocks tst-gettid
tests-internal += tst-ofdlocks-compat


@@ -100,6 +100,8 @@ $(objpfx)tst-sysconf-iov_max: $(objpfx)tst-sysconf-iov_max-uapi.o

$(objpfx)tst-pkey: $(shared-thread-library)

+$(objpfx)tst-gettid: $(shared-thread-library)
+
endif # $(subdir) == misc

ifeq ($(subdir),time)
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index 336c13b57d..6b5cd99b51 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -171,6 +171,9 @@ libc {
mlock2;
pkey_alloc; pkey_free; pkey_set; pkey_get; pkey_mprotect;
}
+ GLIBC_2.29 {
+ gettid;
+ }
GLIBC_PRIVATE {
# functions used in other libraries
__syscall_rt_sigqueueinfo;
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index e66c741d04..a9851a9450 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2138,4 +2138,5 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index 8df162fe99..b9cdd685e4 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2033,6 +2033,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist
index 43c804f9dc..958d9d4f2b 100644
--- a/sysdeps/unix/sysv/linux/arm/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/libc.abilist
@@ -123,6 +123,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.4 _Exit F
GLIBC_2.4 _IO_2_1_stderr_ D 0xa0
diff --git a/sysdeps/unix/sysv/linux/bits/unistd_ext.h b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
new file mode 100644
index 0000000000..5f964bca94
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
@@ -0,0 +1,32 @@
+/* System-specific extensions of <unistd.h>, Linux version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _UNISTD_H
+# error "Never include <bits/unistd_ext.h> directly; use <unistd.h> instead."
+#endif
+
+#ifdef __USE_GNU
+
+/* Return the kernel thread ID (TID) of the current thread. The
+ returned value is not subject to caching. Note that a TID uniquely
+ identifies a thread only while this thread is running; a TID can be
+ reused once a thread has exited, even if the thread is not detached
+ and has not been joined. */
+extern __pid_t gettid (void) __THROW;
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index 88b01c2e75..ff3656d3bb 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -1880,6 +1880,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index 6d02f31612..9abad3352d 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2045,6 +2045,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index 4249712611..1c1018e84e 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -1914,6 +1914,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index d47b808862..f8f6c42be4 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -124,6 +124,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.4 _Exit F
GLIBC_2.4 _IO_2_1_stderr_ D 0x98
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
index d5e38308be..8d73f730b7 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -1989,6 +1989,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
index 8596b84399..21daf81c03 100644
--- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
@@ -2130,4 +2130,5 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index 88e0f896d5..0e519f164b 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -1967,6 +1967,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
index aff7462c34..da97eae834 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -1965,6 +1965,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
index 71d82444aa..d522182d71 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -1973,6 +1973,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
index de6c53d293..b284b21f78 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -1968,6 +1968,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist
index e724bab9fb..dbbe729e18 100644
--- a/sysdeps/unix/sysv/linux/nios2/libc.abilist
+++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist
@@ -2171,4 +2171,5 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
index e9ecbccb71..35231739ea 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
@@ -1993,6 +1993,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
index da83ea6028..cea0accf60 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
@@ -1997,6 +1997,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
index 4535b40d15..55d2d0c621 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
@@ -2228,4 +2228,5 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
index 65725de4f0..a4962c13a8 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
@@ -123,6 +123,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 _Exit F
GLIBC_2.3 _IO_2_1_stderr_ D 0xe0
diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
index bbb3c4a8e7..06372f7b97 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
@@ -2100,4 +2100,5 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
index e85ac2a178..403f30aa3e 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
@@ -2002,6 +2002,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
index d56931022c..c5095fad6f 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
@@ -1908,6 +1908,7 @@ GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
GLIBC_2.29 __fentry__ F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist
index ff939a15c4..9b4b9328d3 100644
--- a/sysdeps/unix/sysv/linux/sh/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/libc.abilist
@@ -1884,6 +1884,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
index 64fa9e10a5..5c3480af84 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
@@ -1996,6 +1996,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
index db909d1506..2928506213 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
@@ -1937,6 +1937,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index e24ea29e35..544ab5d54a 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -112,3 +112,4 @@ process_vm_writev EXTRA process_vm_writev i:ipipii process_vm_writev
memfd_create EXTRA memfd_create i:si memfd_create
pkey_alloc EXTRA pkey_alloc i:ii pkey_alloc
pkey_free EXTRA pkey_free i:i pkey_free
+gettid EXTRA gettid Ei: __gettid gettid
diff --git a/sysdeps/unix/sysv/linux/tst-gettid.c b/sysdeps/unix/sysv/linux/tst-gettid.c
new file mode 100644
index 0000000000..78bbaee4f3
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-gettid.c
@@ -0,0 +1,79 @@
+/* Smoke test for the gettid system call.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <support/check.h>
+#include <support/namespace.h>
+#include <support/xthread.h>
+#include <support/xunistd.h>
+
+/* TID of the initial (main) thread. */
+static pid_t initial_tid;
+
+/* Check that PID and TID are the same in a subprocess. */
+static void
+subprocess (void *closure)
+{
+ TEST_COMPARE (getpid (), gettid ());
+ TEST_VERIFY (gettid () != initial_tid);
+}
+
+/* Check that the TID changes in a new thread. */
+static void *
+threadfunc (void *closure)
+{
+ TEST_VERIFY (getpid () != gettid ());
+ TEST_VERIFY (gettid () != initial_tid);
+ return NULL;
+}
+
+/* Check for interactions with vfork. */
+static void
+test_vfork (void)
+{
+ pid_t proc = vfork ();
+ if (proc == 0)
+ {
+ if (getpid () != gettid ())
+ _exit (1);
+ if (gettid () == initial_tid)
+ _exit (2);
+ _exit (0);
+ }
+ int status;
+ xwaitpid (proc, &status, 0);
+ TEST_COMPARE (status, 0);
+}
+
+static int
+do_test (void)
+{
+ initial_tid = gettid ();
+
+ /* The main thread has the same TID as the PID. */
+ TEST_COMPARE (getpid (), gettid ());
+
+ test_vfork ();
+
+ support_isolate_in_subprocess (subprocess, NULL);
+
+ xpthread_join (xpthread_create (NULL, threadfunc, NULL));
+
+ return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/unix/sysv/linux/tst-setgetname.c b/sysdeps/unix/sysv/linux/tst-setgetname.c
index b80ff59074..95d8bb9ba4 100644
--- a/sysdeps/unix/sysv/linux/tst-setgetname.c
+++ b/sysdeps/unix/sysv/linux/tst-setgetname.c
@@ -43,12 +43,6 @@
terminator. */
#define TASK_COMM_LEN 16

-long
-gettid (void)
-{
- return syscall(__NR_gettid);
-}
-
/* On Linux we can read this task's name from /proc. */
int
get_self_comm (long tid, char *buf, size_t len)
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index 3b175f104b..ae93b8719b 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -1895,6 +1895,7 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.3 __ctype_b_loc F
GLIBC_2.3 __ctype_tolower_loc F
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
index 1b57710477..02110bac19 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2146,4 +2146,5 @@ GLIBC_2.28 thrd_current F
GLIBC_2.28 thrd_equal F
GLIBC_2.28 thrd_sleep F
GLIBC_2.28 thrd_yield F
+GLIBC_2.29 gettid F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
Joseph Myers
2018-12-05 16:20:14 UTC
Permalink
Post by Florian Weimer
This commit adds gettid to <unistd.h> on Linux, and not to the
kernel-independent GNU API.
This is missing a NEWS entry, and documentation (which seems particularly
important in this case, to discuss what a tid is and is not and what
interfaces it can be used with).
--
Joseph S. Myers
***@codesourcery.com
Florian Weimer
2018-12-05 18:24:53 UTC
Permalink
Post by Joseph Myers
Post by Florian Weimer
This commit adds gettid to <unistd.h> on Linux, and not to the
kernel-independent GNU API.
This is missing a NEWS entry,
I plan to add this:

+* On Linux, the gettid function has been added.
Post by Joseph Myers
and documentation (which seems particularly
important in this case, to discuss what a tid is and is not and what
interfaces it can be used with).
I can put more details into the comment:

/* Return the kernel thread ID (TID) of the current thread. The
returned value is not subject to caching. Most Linux system calls
accept a TID in place of a PID. Using the TID to change properties
of a thread that has been created using pthread_create can lead to
undefined behavior (comparable to manipulating file descriptors
directly that have not been created explicitly). Note that a TID
uniquely identifies a thread only while this thread is running; a
TID can be reused once a thread has exited, even if the thread is
not detached and has not been joined. */

I do not want to contribute to the manual at this point.

I would rather improve the manpages project documentation and clarify
there when a PID is actually a TID and deals with what are essentially
task properties.

Should we have a separate conversation about the future of the manual?

Thanks,
Florian
Joseph Myers
2018-12-05 18:30:01 UTC
Permalink
Post by Florian Weimer
I do not want to contribute to the manual at this point.
I think additions to the manual should generally be required for adding
new functions to glibc.

I'm also wondering about adding a testcase that fails if any undocumented
function is declared in a header unless the lack of documentation for that
function is XFAILed with reference to an open bug, to make it more obvious
when documentation is missing from a patch submission.
--
Joseph S. Myers
***@codesourcery.com
Carlos O'Donell
2018-12-07 13:28:18 UTC
Permalink
Post by Joseph Myers
Post by Florian Weimer
I do not want to contribute to the manual at this point.
I think additions to the manual should generally be required for adding
new functions to glibc.
I agree, even if the documentation is minimal, and you can always ask for
help in writing the manual pages.
Post by Joseph Myers
I'm also wondering about adding a testcase that fails if any undocumented
function is declared in a header unless the lack of documentation for that
function is XFAILed with reference to an open bug, to make it more obvious
when documentation is missing from a patch submission.
Agreed.
--
Cheers,
Carlos.
Christian Brauner
2018-12-10 11:35:20 UTC
Permalink
Post by Joseph Myers
Post by Joseph Myers
Post by Florian Weimer
I do not want to contribute to the manual at this point.
I think additions to the manual should generally be required for
adding
Post by Joseph Myers
new functions to glibc.
<https://sourceware.org/ml/libc-alpha/2018-12/msg00236.html>
Florian, if this is not just about POSIX but also about the actual implementation
could you maybe add a section to the manual what happens when:
- the thread-group leader exits
- the thread-group leader becomes a zombie
- whether a thread-group can be reparented
?
Obviously all three are closely related.

Christian
Post by Joseph Myers
<https://sourceware.org/ml/libc-alpha/2018-12/msg00237.html>
Once at least the first one is in, I can add documentation for gettid
as
well.
Thanks,
Florian
Florian Weimer
2018-12-10 12:02:46 UTC
Permalink
Post by Christian Brauner
Florian, if this is not just about POSIX but also about the actual
implementation could you maybe add a section to the manual what
- the thread-group leader exits
- the thread-group leader becomes a zombie
- whether a thread-group can be reparented
?
Obviously all three are closely related.
I lack the technical expertise in this area to do this, but input is
welcome. I can probably come up with wording. Some of this should
perhaps go to the man-pages project because I think the glibc manual
should document only cases which are possible to observe with the glibc
implementation (with NPTL using CLONE_THREAD etc.).

I think we really need to document the different effects of returning
from main (or calling exit directly) on the one hand, and calling
pthread_exit from the main thread on the other. Some of the thread
group behavior could be included in that.

Thanks,
Florian
Christian Brauner
2018-12-10 12:08:11 UTC
Permalink
Post by Florian Weimer
Post by Christian Brauner
Florian, if this is not just about POSIX but also about the actual
implementation could you maybe add a section to the manual what
- the thread-group leader exits
- the thread-group leader becomes a zombie
- whether a thread-group can be reparented
?
Obviously all three are closely related.
I lack the technical expertise in this area to do this, but input is
welcome. I can probably come up with*
*If* [sic!] pidfd_send_signal() gets in I have
follow up patches that do allow sending signals to process groups and threads.
I've been looking into the exact behavior
of thread-groups and process groups
so I can spend some time documenting it.
I will have to write this down for myself anyway. (If I haven't made it clear: that's a big *if* on whether signaling via fds lands).
Post by Florian Weimer
wording. Some of this should
perhaps go to the man-pages project because I think the glibc manual
should document only cases which are possible to observe with the glibc
implementation (with NPTL using CLONE_THREAD etc.).
I think we really need to document the different effects of returning
from main (or calling exit directly) on the one hand, and calling
pthread_exit from the main thread on the other. Some of the thread
group behavior could be included in that.
Very much agreed!

Thanks for all the work!
Christian
Post by Florian Weimer
Thanks,
Florian
Florian Weimer
2018-12-07 08:48:20 UTC
Permalink
Post by Florian Weimer
This commit adds gettid to <unistd.h> on Linux, and not to the
kernel-independent GNU API.
[BZ #6399]
Linux: Add gettid system call wrapper.
* posix/Makefile (headers): Add bits/unistd_ext.h.
* posix/bits/unistd_ext.h: New file.
* posix/unistd.h: Include it.
* sysdeps/unix/sysv/linux/Makefile [subdir == misc] (tests): Add
tst-gettid.
(tst-gettid): Link with $(shared-thread-library).
* sysdeps/unix/sysv/linux/Version (GLIBC_2.29): Export gettid.
* sysdeps/unix/sysv/linux/bits/unistd_ext.h: New file.
Any comments on the technical approach chosen here? Is the declaration
in <unistd.h> reasonable? Is the mechanism to make <unistd.h>
extensible okay?

Or should the prototype go into <sched.h>?

Thanks,
Florian
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