Linux: Add the tgkill function

The tgkill function is sometimes used in crash handlers.

<bits/signal_ext.h> follows the same approach as <bits/unistd_ext.h>
(which was added for the gettid system call wrapper).

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

38 files changed, 282 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index edfb9ad96b..cfdfcd57b7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,49 @@
+2019-05-14  Florian Weimer  <fweimer@redhat.com>
+
+	Linux: Add the tgkill function.
+	* bits/signal_ext.h: New file.
+	* manual/signal.texi (Signaling Another Process): Document tgkill.
+	* signal/Makefile (headers): Add bits/signal_ext.h.
+	* signal/signal.h: Include <bits/signal_ext.h>.
+	* sysdeps/unix/sysv/linux/Makefile (tests): Add tst-tgkill.
+	(tst-tgkill): Link with libpthread.
+	* sysdeps/unix/sysv/linux/Versions (GLIBC_2.30): Export tgkill.
+	* sysdeps/unix/sysv/linux/bits/signal_ext.h: New file.
+	* sysdeps/unix/sysv/linux/bits/tst-tgkill.c: Likewise.
+	* sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.30): Add
+	tgkill.
+	* sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/arm/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/csky/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/hppa/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/i386/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/ia64/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/microblaze/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist:
+	Likewise.
+	* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/nios2/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist:
+	Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist:
+	Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist:
+	Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist:
+	Likewise.
+	* sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/sh/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
+	* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise.
+
 2019-05-14  Carlos O'Donell  <carlos@redhat.com>
 
 	* manual/search.texi (Tree Search Function): Adjust twalk_r
diff --git a/NEWS b/NEWS
index 7f5ef432fa..0e4c57f273 100644
--- a/NEWS
+++ b/NEWS
@@ -20,7 +20,7 @@ Major new features:
   twalk function, but it passes an additional caller-supplied argument
   to the callback function.
 
-* On Linux, the gettid function has been added.
+* On Linux, the gettid and tgkill functions have been added.
 
 * Minguo (Republic of China) calendar support has been added as an
   alternative calendar for the following locales: zh_TW, cmn_TW, hak_TW,
diff --git a/bits/signal_ext.h b/bits/signal_ext.h
new file mode 100644
index 0000000000..d1bed56e55
--- /dev/null
+++ b/bits/signal_ext.h
@@ -0,0 +1,21 @@
+/* System-specific extensions of <signal.h>, generic version.
+   Copyright (C) 2019 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 _SIGNAL_H
+# error "Never include <bits/signal_ext.h> directly; use <signal.h> instead."
+#endif
diff --git a/manual/signal.texi b/manual/signal.texi
index 8b3a52e22a..33e6646975 100644
--- a/manual/signal.texi
+++ b/manual/signal.texi
@@ -2291,6 +2291,21 @@ The @var{pid} argument does not refer to an existing process or group.
 @end table
 @end deftypefun
 
+@deftypefun int tgkill (pid_t @var{pid}, pid_t @var{tid}, int @var{signum})
+@standards{Linux, signal.h}
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+The @code{tgkill} function sends the signal @var{signum} to the thread
+or process with ID @var{tid}, like the @code{kill} function, but only
+if the process ID of the thread @var{tid} is equal to @var{pid}.  If
+the target thread belongs to another process, the function fails with
+@code{ESRCH}.
+
+The @code{tgkill} function can be used to avoid sending a signal to a
+thread in the wrong process if the caller ensures that the passed
+@var{pid} value is not reused by the kernel (for example, if it is the
+process ID of the current process, as returned by @code{getpid}).
+@end deftypefun
+
 @deftypefun int killpg (int @var{pgid}, int @var{signum})
 @standards{BSD, signal.h}
 @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
diff --git a/signal/Makefile b/signal/Makefile
index 06034fee8e..4596112f0a 100644
--- a/signal/Makefile
+++ b/signal/Makefile
@@ -31,7 +31,7 @@ headers := signal.h sys/signal.h \
 	   bits/types/sigevent_t.h bits/types/siginfo_t.h \
 	   bits/types/sigset_t.h bits/types/sigval_t.h \
 	   bits/types/stack_t.h bits/types/struct_sigstack.h \
-	   bits/types/__sigval_t.h
+	   bits/types/__sigval_t.h bits/signal_ext.h
 
 routines	:= signal raise killpg \
 		   sigaction sigprocmask kill \
diff --git a/signal/signal.h b/signal/signal.h
index ee591fcb2d..4c0de7f6ce 100644
--- a/signal/signal.h
+++ b/signal/signal.h
@@ -370,6 +370,9 @@ extern int __libc_current_sigrtmax (void) __THROW;
 #define SIGRTMIN        (__libc_current_sigrtmin ())
 #define SIGRTMAX        (__libc_current_sigrtmax ())
 
+/* System-specific extensions.  */
+#include <bits/signal_ext.h>
+
 __END_DECLS
 
 #endif /* not signal.h */
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 52ac6ad484..d2f0b60ea9 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -53,7 +53,8 @@ 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-gettid tst-gettid-kill
+	 tst-rlimit-infinity tst-ofdlocks tst-gettid tst-gettid-kill \
+	 tst-tgkill
 tests-internal += tst-ofdlocks-compat
 
 # Generate the list of SYS_* macros for the system calls (__NR_*
@@ -115,6 +116,7 @@ $(objpfx)tst-mman-consts.out: ../sysdeps/unix/sysv/linux/tst-mman-consts.py
 
 $(objpfx)tst-gettid: $(shared-thread-library)
 $(objpfx)tst-gettid-kill: $(shared-thread-library)
+$(objpfx)tst-tgkill: $(shared-thread-library)
 
 endif # $(subdir) == misc
 
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index 5166ccff25..c7137e2c2c 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -175,7 +175,7 @@ libc {
     getcpu;
   }
   GLIBC_2.30 {
-    gettid;
+    gettid; tgkill;
   }
   GLIBC_PRIVATE {
     # functions used in other libraries
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index b7283ad486..324909d553 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2142,4 +2142,5 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index a817e683a4..084e475569 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2217,6 +2217,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist
index 97b6cbf903..f58d16e210 100644
--- a/sysdeps/unix/sysv/linux/arm/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/libc.abilist
@@ -127,6 +127,7 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 _Exit F
 GLIBC_2.4 _IO_2_1_stderr_ D 0xa0
diff --git a/sysdeps/unix/sysv/linux/bits/signal_ext.h b/sysdeps/unix/sysv/linux/bits/signal_ext.h
new file mode 100644
index 0000000000..c07b869fab
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/bits/signal_ext.h
@@ -0,0 +1,31 @@
+/* System-specific extensions of <signal.h>, Linux version.
+   Copyright (C) 2019 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 _SIGNAL_H
+# error "Never include <bits/signal_ext.h> directly; use <signal.h> instead."
+#endif
+
+#ifdef __USE_GNU
+
+/* Send SIGNAL to the thread TID in the thread group (process)
+   identified by TGID.  This function behaves like kill, but also
+   fails with ESRCH if the specified TID does not belong to the
+   specified thread group.  */
+extern int tgkill (__pid_t __tgid, __pid_t __tid, int __signal);
+
+#endif /* __USE_GNU */
diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist
index 796e622a6d..38f6abaa30 100644
--- a/sysdeps/unix/sysv/linux/csky/libc.abilist
+++ b/sysdeps/unix/sysv/linux/csky/libc.abilist
@@ -2086,4 +2086,5 @@ GLIBC_2.29 xencrypt F
 GLIBC_2.29 xprt_register F
 GLIBC_2.29 xprt_unregister F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index 4e7d71d112..eb628f907b 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -2038,6 +2038,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index 11bd8c601a..6f240d9a59 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2204,6 +2204,7 @@ GLIBC_2.3.4 vm86 F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index 589cce5b8d..e589e3d7e2 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -2070,6 +2070,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index 4b3727a91d..02c3ceee8d 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -128,6 +128,7 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r 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 4be30c0339..f9a86bd951 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -2147,6 +2147,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
index e0010965a8..d153fe0df5 100644
--- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
@@ -2134,4 +2134,5 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index 2a62f67741..fb3a9b18fc 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -2121,6 +2121,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
index 5a23f11fc9..22c80418f6 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -2119,6 +2119,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
index 32532a19da..a32aafb552 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -2127,6 +2127,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
index 882f5cb5bf..45342a587e 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -2121,6 +2121,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist
index c99a299bab..fe1e96c170 100644
--- a/sysdeps/unix/sysv/linux/nios2/libc.abilist
+++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist
@@ -2175,4 +2175,5 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
index d5f4364197..cbcad5db98 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
@@ -2177,6 +2177,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
index 581fd10290..060994eccf 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
@@ -2210,6 +2210,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
index ce10e0436e..af68ed8d01 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
@@ -2040,6 +2040,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
index 1cc729da7f..d317dc0586 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
@@ -2244,4 +2244,5 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
index 2bda5692f4..07d75c0481 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
@@ -2104,4 +2104,5 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
index dddc138a1e..0fdcd6109c 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
@@ -2172,6 +2172,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
index b2c75a48a8..ca871ad4be 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
@@ -2076,6 +2076,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist
index 8b83449b16..b559e5b316 100644
--- a/sysdeps/unix/sysv/linux/sh/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/libc.abilist
@@ -2042,6 +2042,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
index a237be9d93..37daaa28e4 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
@@ -2166,6 +2166,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
index b850694434..5f0a3adc3c 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
@@ -2093,6 +2093,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index 25424e1399..e374f97b5f 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -111,3 +111,4 @@ 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
+tgkill          EXTRA   tgkill          i:iii   __tgkill	tgkill
diff --git a/sysdeps/unix/sysv/linux/tst-tgkill.c b/sysdeps/unix/sysv/linux/tst-tgkill.c
new file mode 100644
index 0000000000..818e2f58da
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-tgkill.c
@@ -0,0 +1,132 @@
+/* Smoke test for the tgkill system call.
+   Copyright (C) 2019 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 <errno.h>
+#include <signal.h>
+#include <support/check.h>
+#include <support/namespace.h>
+#include <support/xthread.h>
+#include <unistd.h>
+
+/* Number of times sigusr1_handler has been invoked.  */
+static volatile sig_atomic_t signals_delivered;
+
+/* Expected TID of the thread receiving the signal.  */
+static pid_t expected_signal_tid;
+
+static void
+sigusr1_handler (int signo)
+{
+  TEST_COMPARE (expected_signal_tid, gettid ());
+  ++signals_delivered;
+}
+
+struct pid_and_tid
+{
+  pid_t pid;
+  pid_t tid;
+};
+
+/* Send signals from the subprocess which are not expected to be
+   delivered.  There is no handler for SIGUSR2, so delivery will
+   result in a test failure.  CLOSURE must point to a valid PID/TID
+   combination that is still running.  */
+static void
+subprocess_no_tid_match (void *closure)
+{
+  struct pid_and_tid *ids = closure;
+  TEST_COMPARE (tgkill (ids->pid, gettid (), SIGUSR2), -1);
+  TEST_COMPARE (errno, ESRCH);
+
+  TEST_COMPARE (tgkill (getpid (), ids->tid, SIGUSR2), -1);
+  TEST_COMPARE (errno, ESRCH);
+
+  TEST_COMPARE (tgkill (getppid (), gettid (), SIGUSR2), -1);
+  TEST_COMPARE (errno, ESRCH);
+}
+
+/* Called from threadfunc below.  */
+static void
+subprocess (void *closure)
+{
+  int original_tid = expected_signal_tid;
+
+  /* Do not expect that the folloing signals are delivered to the
+     subprocess.  The parent process retains the original
+     expected_signal_tid value.  */
+  expected_signal_tid = 0;
+  TEST_COMPARE (tgkill (getpid (), original_tid, SIGUSR1), -1);
+  TEST_COMPARE (errno, ESRCH);
+  TEST_COMPARE (tgkill (getppid (), gettid (), SIGUSR1), -1);
+  TEST_COMPARE (errno, ESRCH);
+  TEST_COMPARE (expected_signal_tid, 0);
+
+  /* This call has the correct PID/TID combination and is therefore
+     expected to suceed.  */
+  TEST_COMPARE (tgkill (getppid (), original_tid, SIGUSR1), 0);
+}
+
+static void *
+threadfunc (void *closure)
+{
+  TEST_VERIFY (gettid () != getpid ());
+  expected_signal_tid = gettid ();
+  TEST_COMPARE (tgkill (getpid (), gettid (), SIGUSR1), 0);
+  TEST_COMPARE (signals_delivered, 1);
+  signals_delivered = 0;
+
+  support_isolate_in_subprocess (subprocess, NULL);
+
+  /* Check that exactly one signal arrived from the subprocess.  */
+  TEST_COMPARE (signals_delivered, 1);
+
+  support_isolate_in_subprocess (subprocess_no_tid_match,
+                                 &(struct pid_and_tid)
+                                 {
+                                   .pid = getpid (),
+                                   .tid = gettid (),
+                                 });
+
+  support_isolate_in_subprocess (subprocess_no_tid_match,
+                                 &(struct pid_and_tid)
+                                 {
+                                   .pid = getpid (),
+                                   .tid = getpid (),
+                                 });
+
+  return NULL;
+}
+
+static int
+do_test (void)
+{
+  TEST_VERIFY_EXIT (signal (SIGUSR1, sigusr1_handler) != SIG_ERR);
+
+  expected_signal_tid = gettid ();
+  TEST_COMPARE (gettid (), getpid ());
+  TEST_COMPARE (tgkill (getpid (), gettid (), SIGUSR1), 0);
+  TEST_COMPARE (signals_delivered, 1);
+  signals_delivered = 0;
+
+  xpthread_join (xpthread_create (NULL, threadfunc, NULL));
+
+  TEST_VERIFY (signal (SIGUSR1, SIG_DFL) == sigusr1_handler);
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index c6f22f0c7b..c82b3ba7b8 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -2051,6 +2051,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
index 1184385bce..ed89c34c55 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2150,4 +2150,5 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F