signal: Move sys_siglist to a compat symbol

The symbol was deprecated by strsignal and its usage imposes issues
such as copy relocations.

Its internal name is changed to __sys_siglist and __sys_sigabbrev to
avoid static linking usage.  The compat code is also refactored, since
both Linux and Hurd usage the same strategy: export the same array with
different object sizes.

The libSegfault change avoids calling strsignal on the SIGFAULT signal
handler (the current usage is already sketchy, adding a call that
potentially issue locale internal function is even sketchier).

Checked on x86_64-linux-gnu and i686-linux-gnu. I also run a check-abi
on all affected platforms.

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

5 files changed, 69 insertions, 87 deletions

diff --git a/sysdeps/generic/siglist-compat.c b/sysdeps/generic/siglist-compat.c
new file mode 100644
index 0000000000..6e25b021ab
--- /dev/null
+++ b/sysdeps/generic/siglist-compat.c
@@ -0,0 +1 @@
+/* Empty.  */
diff --git a/sysdeps/generic/siglist-compat.h b/sysdeps/generic/siglist-compat.h
new file mode 100644
index 0000000000..13e5f253dc
--- /dev/null
+++ b/sysdeps/generic/siglist-compat.h
@@ -0,0 +1,47 @@
+/* Generic siglist compatibility macro definitions.
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _SIGLIST_COMPAT_H
+#define _SIGLIST_COMPAT_H
+
+#include <shlib-compat.h>
+#include <limits.h>
+
+/* Define new compat symbols for sys_siglist, _sys_siglist, and sys_sigabbrev
+   for version VERSION with NUMBERSIG times the number of bytes per long int.
+   Both _sys_siglist and sys_siglist alias to __sys_siglist while
+   sys_sigabbrev alias to __sys_sigabbrev.  Both target alias are
+   define in siglist.c.  */
+#define DEFINE_COMPAT_SIGLIST(NUMBERSIG, VERSION) 			     \
+  declare_symbol_alias (__ ## VERSION ## _sys_siglist,			     \
+			__sys_siglist,					     \
+			object,	NUMBERSIG * (ULONG_WIDTH / UCHAR_WIDTH));    \
+  declare_symbol_alias (__ ## VERSION ## sys_siglist,			     \
+			__sys_siglist,					     \
+			object,	NUMBERSIG * (ULONG_WIDTH / UCHAR_WIDTH));    \
+  declare_symbol_alias (__ ## VERSION ## _sys_sigabbrev,		     \
+			__sys_sigabbrev,				     \
+			object, NUMBERSIG * (ULONG_WIDTH / UCHAR_WIDTH));    \
+  compat_symbol (libc, __## VERSION ## _sys_siglist,   _sys_siglist,	     \
+		 VERSION);						     \
+  compat_symbol (libc, __## VERSION ## sys_siglist,    sys_siglist,	     \
+		 VERSION);						     \
+  compat_symbol (libc, __## VERSION ## _sys_sigabbrev, sys_sigabbrev,	     \
+		 VERSION);						     \
+
+#endif
diff --git a/sysdeps/gnu/siglist.c b/sysdeps/gnu/siglist.c
deleted file mode 100644
index c24f356f21..0000000000
--- a/sysdeps/gnu/siglist.c
+++ /dev/null
@@ -1,78 +0,0 @@
-/* Define list of all signal numbers and their names.
-   Copyright (C) 1997-2020 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
-   <https://www.gnu.org/licenses/>.  */
-
-#include <stddef.h>
-#include <signal.h>
-#include <libintl.h>
-#include <shlib-compat.h>
-#include <bits/wordsize.h>
-
-const char *const __new_sys_siglist[NSIG] =
-{
-#define init_sig(sig, abbrev, desc)   [sig] = desc,
-#include <siglist.h>
-#undef init_sig
-};
-libc_hidden_ver (__new_sys_siglist, _sys_siglist)
-
-const char *const __new_sys_sigabbrev[NSIG] =
-{
-#define init_sig(sig, abbrev, desc)   [sig] = abbrev,
-#include <siglist.h>
-#undef init_sig
-};
-
-#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
-declare_symbol_alias (__old_sys_siglist, __new_sys_siglist, object,
-		      OLD_SIGLIST_SIZE * __WORDSIZE / 8)
-
-declare_symbol_alias (__old_sys_sigabbrev, __new_sys_sigabbrev, object,
-		      OLD_SIGLIST_SIZE * __WORDSIZE / 8)
-
-declare_symbol_alias (_old_sys_siglist, __new_sys_siglist, object,
-		      OLD_SIGLIST_SIZE * __WORDSIZE / 8)
-
-compat_symbol (libc, __old_sys_siglist, _sys_siglist, GLIBC_2_0);
-compat_symbol (libc, _old_sys_siglist, sys_siglist, GLIBC_2_0);
-compat_symbol (libc, __old_sys_sigabbrev, sys_sigabbrev, GLIBC_2_0);
-#endif
-
-#if SHLIB_COMPAT (libc, GLIBC_2_1, GLIBC_2_3_3) && defined OLD2_SIGLIST_SIZE
-declare_symbol_alias (__old2_sys_siglist, __new_sys_siglist, object,
-		      OLD2_SIGLIST_SIZE * __WORDSIZE / 8)
-
-declare_symbol_alias (__old2_sys_sigabbrev, __new_sys_sigabbrev, object,
-		      OLD2_SIGLIST_SIZE * __WORDSIZE / 8)
-
-declare_symbol_alias (_old2_sys_siglist, __new_sys_siglist, object,
-		      OLD2_SIGLIST_SIZE * __WORDSIZE / 8)
-
-compat_symbol (libc, __old2_sys_siglist, _sys_siglist, GLIBC_2_1);
-compat_symbol (libc, _old2_sys_siglist, sys_siglist, GLIBC_2_1);
-compat_symbol (libc, __old2_sys_sigabbrev, sys_sigabbrev, GLIBC_2_1);
-
-strong_alias (__new_sys_siglist, _new_sys_siglist)
-versioned_symbol (libc, __new_sys_siglist, _sys_siglist, GLIBC_2_3_3);
-versioned_symbol (libc, _new_sys_siglist, sys_siglist, GLIBC_2_3_3);
-versioned_symbol (libc, __new_sys_sigabbrev, sys_sigabbrev, GLIBC_2_3_3);
-#else
-strong_alias (__new_sys_siglist, _new_sys_siglist)
-versioned_symbol (libc, __new_sys_siglist, _sys_siglist, GLIBC_2_1);
-versioned_symbol (libc, _new_sys_siglist, sys_siglist, GLIBC_2_1);
-versioned_symbol (libc, __new_sys_sigabbrev, sys_sigabbrev, GLIBC_2_1);
-#endif
diff --git a/sysdeps/mach/hurd/siglist.h b/sysdeps/mach/hurd/siglist-compat.c
index 2eee091610..c93f12366b 100644
--- a/sysdeps/mach/hurd/siglist.h
+++ b/sysdeps/mach/hurd/siglist-compat.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 1999-2020 Free Software Foundation, Inc.
+/* Compatibility signal numbers and their names symbols.  Hurd version.
+   Copyright (C) 1997-2020 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
@@ -15,8 +16,12 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-/* This file is included multiple times.  */
+#include <siglist-compat.h>
 
-#include_next <siglist.h>	/* Get the canonical list.  */
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
+DEFINE_COMPAT_SIGLIST (33, GLIBC_2_0)
+#endif
 
-#define	OLD_SIGLIST_SIZE	33 /* For GLIBC_2.0 binary compatibility.  */
+#if SHLIB_COMPAT (libc, GLIBC_2_1, GLIBC_2_32)
+DEFINE_COMPAT_SIGLIST (NSIG, GLIBC_2_1)
+#endif
diff --git a/sysdeps/unix/sysv/linux/siglist.h b/sysdeps/unix/sysv/linux/siglist-compat.c
index 6ff2c613ad..c322326a99 100644
--- a/sysdeps/unix/sysv/linux/siglist.h
+++ b/sysdeps/unix/sysv/linux/siglist-compat.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 1996-2020 Free Software Foundation, Inc.
+/* Compatibility signal numbers and their names symbols.  Linux version.
+   Copyright (C) 1997-2020 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
@@ -15,10 +16,16 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-/* This file is included multiple times.  */
+#include <siglist-compat.h>
 
-#include_next <siglist.h>	/* Get the canonical list.  */
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
+DEFINE_COMPAT_SIGLIST (32, GLIBC_2_0)
+#endif
 
-#define	OLD_SIGLIST_SIZE	32 /* For GLIBC_2.0 binary compatibility.  */
+#if SHLIB_COMPAT (libc, GLIBC_2_1, GLIBC_2_3_3)
+DEFINE_COMPAT_SIGLIST (64, GLIBC_2_1)
+#endif
 
-#define OLD2_SIGLIST_SIZE	64 /* For GLIBC_2.1 binary compatibility.  */
+#if SHLIB_COMPAT (libc, GLIBC_2_3_3, GLIBC_2_32)
+DEFINE_COMPAT_SIGLIST (NSIG, GLIBC_2_3_3)
+#endif