signal: Move sys_errlist to a compat symbol

The symbol is deprecated by strerror since its usage imposes some issues
such as copy relocations.

Its internal name is also changed to _sys_errlist_internal to avoid
static linking usage.  The compat code is also refactored by removing
the over enginered errlist-compat.c generation from manual entried and
extra comment token in linker script file.  It disantangle the code
generation from manual and simplify both Linux and Hurd compat code.

The definitions from errlist.c are moved to errlist.h and a new test
is added to avoid a new errno entry without an associated one in manual.

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

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

30 files changed, 1115 insertions, 1898 deletions

diff --git a/NEWS b/NEWS
index b93c06d744..482d2253e0 100644
--- a/NEWS
+++ b/NEWS
@@ -73,6 +73,12 @@ Deprecated and removed features, and other changes affecting compatibility:
   compatibility symbols to support old binaries.  All programs should use
   strsignal instead.
 
+* The deprecated symbols sys_errlist, _sys_errlist, sys_nerr, and _sys_nerr
+  are no longer available to newly linked binaries, and their declarations
+  have been removed from from <stdio.h>.  They are exported solely as
+  compatibility symbols to support old binaries.  All programs should use
+  strerror or strerror_r instead.
+
 Changes to build and runtime requirements:
 
 * powerpc64le requires GCC 7.4 or newer.  This is required for supporting
diff --git a/include/stdio.h b/include/stdio.h
index 9df98b2833..9e3bf6fe42 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -186,7 +186,7 @@ ssize_t __libc_readline_unlocked (FILE *fp, char *buffer, size_t length);
 libc_hidden_proto (__libc_readline_unlocked);
 
 extern const char *const _sys_errlist_internal[] attribute_hidden;
-extern int _sys_nerr_internal attribute_hidden;
+extern const char *__get_errlist (int) attribute_hidden;
 
 libc_hidden_ldbl_proto (__asprintf)
 
diff --git a/libio/Makefile b/libio/Makefile
index 59e1f68e9c..926df1870b 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -23,7 +23,7 @@ subdir	:= libio
 include ../Makeconfig
 
 headers	:= stdio.h \
-	   bits/stdio.h bits/stdio2.h bits/sys_errlist.h bits/stdio-ldbl.h \
+	   bits/stdio.h bits/stdio2.h bits/stdio-ldbl.h \
 	   bits/types/FILE.h bits/types/__FILE.h bits/types/struct_FILE.h \
 	   bits/types/__fpos_t.h bits/types/__fpos64_t.h \
 	   bits/types/cookie_io_functions_t.h
diff --git a/libio/stdio.h b/libio/stdio.h
index 07f2d9afb5..998470943e 100644
--- a/libio/stdio.h
+++ b/libio/stdio.h
@@ -779,12 +779,6 @@ extern int ferror_unlocked (FILE *__stream) __THROW __wur;
    marked with __THROW.  */
 extern void perror (const char *__s);
 
-/* Provide the declarations for `sys_errlist' and `sys_nerr' if they
-   are available on this system.  Even if available, these variables
-   should not be used directly.  The `strerror' function provides
-   all the necessary functionality.  */
-#include <bits/sys_errlist.h>
-
 
 #ifdef	__USE_POSIX
 /* Return the system file descriptor for STREAM.  */
diff --git a/scripts/build-many-glibcs.py b/scripts/build-many-glibcs.py
index 8c72b9e571..07e9b457da 100755
--- a/scripts/build-many-glibcs.py
+++ b/scripts/build-many-glibcs.py
@@ -892,8 +892,7 @@ class Context(object):
         # Some other files have such dependencies but do not need to
         # be touched because nothing in a build depends on the files
         # in question.
-        for f in ('sysdeps/gnu/errlist.c',
-                  'sysdeps/mach/hurd/bits/errno.h'):
+        for f in ('sysdeps/mach/hurd/bits/errno.h',):
             to_touch = os.path.join(srcdir, f)
             subprocess.run(['touch', '-c', to_touch], check=True)
         for dirpath, dirnames, filenames in os.walk(srcdir):
diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index 1333203046..73bf0da296 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -85,6 +85,8 @@ generated += tst-printf-bz18872.c tst-printf-bz18872.mtrace \
 	     tst-printf-bz25691.mtrace tst-printf-bz25691-mem.out
 endif
 
+tests-special += $(objpfx)tst-errno-manual.out
+
 include ../Rules
 
 ifeq ($(run-built-tests),yes)
@@ -129,6 +131,15 @@ $(objpfx)tst-%-mem.out: $(objpfx)tst-%.out
 	$(common-objpfx)malloc/mtrace $(objpfx)tst-$*.mtrace > $@; \
 	$(evaluate-test)
 
+errlist-h = $(firstword $(wildcard $(addsuffix /errlist.h,$(sysdirs) .)))
+
+$(objpfx)tst-errno-manual.out: tst-errno-manual.py \
+			       $(errlist-h) \
+			       $(..)manual/errno.texi
+	$(PYTHON) tst-errno-manual.py -m $(..)manual/errno.texi \
+				      -e $(errlist-h) > $@; \
+	$(evaluate-test)
+
 CFLAGS-vfprintf.c += -Wno-uninitialized
 CFLAGS-vfwprintf.c += -Wno-uninitialized
 
diff --git a/stdio-common/errlist-compat.c b/stdio-common/errlist-compat.c
new file mode 100644
index 0000000000..6e25b021ab
--- /dev/null
+++ b/stdio-common/errlist-compat.c
@@ -0,0 +1 @@
+/* Empty.  */
diff --git a/stdio-common/errlist.c b/stdio-common/errlist.c
index 91fa789be0..df52356066 100644
--- a/stdio-common/errlist.c
+++ b/stdio-common/errlist.c
@@ -15,22 +15,24 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#include <stdio.h>
+#include <errno.h>
+#include <libintl.h>
 #include <array_length.h>
-#include <stddef.h>
 
-const char *const _sys_errlist[] =
+const char *const _sys_errlist_internal[] =
   {
-    "Error 0",			/* 0 */
-    "Argument out of function's domain", /* 1 = EDOM */
-    "Result out of range",	/* 2 = ERANGE */
-    "Operation not implemented", /* 3 = ENOSYS */
-    "Invalid argument",		/* 4 = EINVAL */
-    "Illegal seek",		/* 5 = ESPIPE */
-    "Bad file descriptor",	/* 6 = EBADF */
-    "Cannot allocate memory",	/* 7 = ENOMEM */
-    "Permission denied",	/* 8 = EACCES */
-    "Too many open files in system", /* 9 = ENFILE */
-    "Too many open files",	/* 10 = EMFILE */
+#define _S(n, str)         [n] = str,
+#include <errlist.h>
+#undef _S
   };
 
-const int _sys_nerr = array_length (_sys_errlist);
+const char *
+__get_errlist (int errnum)
+{
+  if (errnum >= 0 && errnum < array_length (_sys_errlist_internal))
+    return _sys_errlist_internal[errnum];
+  return NULL;
+}
+
+#include <errlist-compat.c>
diff --git a/stdio-common/tst-errno-manual.py b/stdio-common/tst-errno-manual.py
new file mode 100755
index 0000000000..618120f4f0
--- /dev/null
+++ b/stdio-common/tst-errno-manual.py
@@ -0,0 +1,73 @@
+#!/usr/bin/python3
+# Check is all errno definitions at errlist.h documented in the manual.
+# 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/>.
+
+import argparse
+import sys
+import re
+
+RE_MANUAL = re.compile(
+    r'(?:^@errno){(\w+)')
+
+RE_ERRLIST = re.compile(
+    r'\(E[a-zA-Z0-9]+\)')
+
+PASS=0
+FAIL=1
+
+# Each manual entry is in the form:
+#
+#  errno{EAGAIN, 35, Resource temporarily unavailable}
+def parse_manual(f):
+    errlist = [RE_MANUAL.findall(s) for s in f]
+    return map(lambda x : x[0], filter(None, errlist))
+
+# Each errlist entry is in the form:
+#
+#  _S(ERR_MAP(EAGAIN), N_("Resource temporarily unavailable"))
+def parse_errlist(f):
+    errlist = [RE_ERRLIST.findall(s) for s in f]
+    # Each element is '[]' or '['(EAGAIN)']'
+    return map(lambda s : s[0][s[0].find('(')+1:s[0].find(')')],
+               filter(None, errlist))
+
+def check_errno_definitions(manual_fname, errlist_fname):
+    with open(manual_fname, 'r') as mfile, open(errlist_fname, 'r') as efile:
+        merr = parse_manual(mfile)
+        eerr = parse_errlist(efile)
+        diff = set(eerr).difference(merr)
+        if not diff:
+            sys.exit(PASS)
+        else:
+            print("Failure: the following value(s) are not in manual:",
+                  ", ".join(str(e) for e in diff))
+            sys.exit(FAIL)
+
+def main():
+    parser = argparse.ArgumentParser(description='Generate errlist.h')
+    parser.add_argument('-m', dest='manual', metavar='FILE',
+                        help='manual errno texi file')
+    parser.add_argument('-e', dest='errlist', metavar='FILE',
+                        help='errlist with errno definitions')
+    args = parser.parse_args()
+
+    check_errno_definitions(args.manual, args.errlist)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/string/_strerror.c b/string/_strerror.c
index af6be56fdc..01226e3d4b 100644
--- a/string/_strerror.c
+++ b/string/_strerror.c
@@ -36,8 +36,8 @@
 char *
 __strerror_r (int errnum, char *buf, size_t buflen)
 {
-  if (__builtin_expect (errnum < 0 || errnum >= _sys_nerr_internal
-			|| _sys_errlist_internal[errnum] == NULL, 0))
+  char *err = (char *) __get_errlist (errnum);
+  if (__glibc_unlikely (err == NULL))
     {
       /* Buffer we use to print the number in.  For a maximum size for
 	 `int' of 8 bytes we never need more than 20 digits.  */
@@ -68,7 +68,7 @@ __strerror_r (int errnum, char *buf, size_t buflen)
       return buf;
     }
 
-  return (char *) _(_sys_errlist_internal[errnum]);
+  return _(err);
 }
 weak_alias (__strerror_r, strerror_r)
 libc_hidden_def (__strerror_r)
diff --git a/string/strerror_l.c b/string/strerror_l.c
index c8c3d4a6ef..309f42e66b 100644
--- a/string/strerror_l.c
+++ b/string/strerror_l.c
@@ -40,10 +40,8 @@ translate (const char *str, locale_t loc)
 char *
 strerror_l (int errnum, locale_t loc)
 {
-
-
-  if (__builtin_expect (errnum < 0 || errnum >= _sys_nerr_internal
-			|| _sys_errlist_internal[errnum] == NULL, 0))
+  char *err = (char *) __get_errlist (errnum);
+  if (__glibc_unlikely (err == NULL))
     {
       free (last_value);
       if (__asprintf (&last_value, "%s%d",
@@ -53,7 +51,7 @@ strerror_l (int errnum, locale_t loc)
       return last_value;
     }
 
-  return (char *) translate (_sys_errlist_internal[errnum], loc);
+  return (char *) translate (err, loc);
 }
 
 void
diff --git a/string/xpg-strerror.c b/string/xpg-strerror.c
index 5290b63f18..95311b75e9 100644
--- a/string/xpg-strerror.c
+++ b/string/xpg-strerror.c
@@ -32,16 +32,9 @@ __xpg_strerror_r (int errnum, char *buf, size_t buflen)
      string) if errnum is invalid, otherwise it returns a string whose
      storage has indefinite extent.  */
   if (estr == buf)
-    {
-      assert (errnum < 0 || errnum >= _sys_nerr_internal
-	      || _sys_errlist_internal[errnum] == NULL);
-      return EINVAL;
-    }
+    return EINVAL;
   else
     {
-      assert (errnum >= 0 && errnum < _sys_nerr_internal
-	      && _sys_errlist_internal[errnum] != NULL);
-
       size_t estrlen = strlen (estr);
 
       /* Terminate the string in any case.  */
diff --git a/sysdeps/gnu/Makefile b/sysdeps/gnu/Makefile
index 97fcb6fb90..9cf34c8ac6 100644
--- a/sysdeps/gnu/Makefile
+++ b/sysdeps/gnu/Makefile
@@ -15,49 +15,6 @@
 # License along with the GNU C Library; if not, see
 # <https://www.gnu.org/licenses/>.
 
-# Generate the list of strings for errno codes from the section of the
-# manual which documents the codes.
-
-$(..)sysdeps/gnu/errlist.c: $(..)sysdeps/gnu/errlist.awk \
-			    $(..)manual/errno.texi
-	$(AWK) -f $^ > $@-tmp
-# Make it unwritable so noone will edit it by mistake.
-	-chmod a-w $@-tmp
-	mv -f $@-tmp $@
-
-ifeq ($(subdir),stdio-common)
-
-errlist-c = $(firstword $(wildcard $(addsuffix /errlist.c,$(sysdirs) .)))
-
-libof-errlist-compat = extramodules
-
-ifeq ($(build-shared),yes)
-$(objpfx)errlist-compat.c: $(errlist-c) $(..)sysdeps/gnu/errlist-compat.awk \
-			   $(common-objpfx)Versions.v.i $(before-compile)
-else
-$(objpfx)errlist-compat.c: $(errlist-c) $(..)sysdeps/gnu/errlist-compat.awk \
-			   $(before-compile)
-endif
-	$(make-target-directory)
-	$(AWK) -v maxerr=`\
-	  $(CC) -S $(CPPFLAGS) $(CFLAGS) -DEMIT_ERR_MAX $< -o - \
-	  | sed -n 's/^.*@@@[^0-9]*\([0-9]*\)[^0-9]*@@@.*$$/\1/p'` \
-	       -f $(..)sysdeps/gnu/errlist-compat.awk \
-	       $(wildcard $(sysdirs:=/Versions)) > $@T
-# Make it unwritable so noone will edit it by mistake.
-	-chmod a-w $@T
-	mv -f $@T $@
-$(objpfx)errlist-compat.h: $(objpfx)errlist-compat.c
-	sed -n '1p;/ERR_MAX/p' $< > $@T
-	-chmod a-w $@T
-	mv -f $@T $@
-generated += errlist-compat.c errlist-compat.h
-
-# This will force the generation above to happy if need be.
-$(foreach o,$(object-suffixes) $(object-suffixes:=.d),\
-	  $(objpfx)errlist$o): $(objpfx)errlist-compat.h
-endif
-
 ifeq ($(subdir),login)
 sysdep_routines += setutxent getutxent endutxent getutxid getutxline \
 		   pututxline utmpxname updwtmpx getutmpx getutmp
diff --git a/sysdeps/gnu/errlist-compat.awk b/sysdeps/gnu/errlist-compat.awk
deleted file mode 100644
index 07334c63d8..0000000000
--- a/sysdeps/gnu/errlist-compat.awk
+++ /dev/null
@@ -1,133 +0,0 @@
-# awk script to generate errlist-compat.c
-# Copyright (C) 2002-2020 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/>.
-
-#
-# This script takes the Versions file as input and looks for #errlist-compat
-# magic comments, which have the form:
-#	#errlist-compat NNN
-# where NNN is the number of elements in the sys_errlist for that version set.
-# We need the awk variable `maxerr' defined to the current size of sys_errlist.
-#
-# If there is no magic comment matching the current size, we barf.
-# Otherwise we generate code (errlist-compat.c) to define all the
-# necessary compatibility symbols for older, smaller versions of sys_errlist.
-#
-
-# These two rules catch the Versions file contents.
-NF == 2 && $2 == "{" { last_version = $1; next }
-$1 == "#errlist-compat" {
-  # Don't process any further Versions files
-  ARGC = ARGIND + 1;
-  cnt = $2 + 0;
-  if (cnt < 80) {
-    print "*** this line seems bogus:", $0 > "/dev/stderr";
-    exit 1;
-  }
-  version[pos + 0] = cnt SUBSEP last_version;
-  pos++;
-  if (cnt < highest) {
-    printf "*** %s #errlist-compat counts are not sorted\n", ARGV[ARGIND];
-    exit 1;
-  }
-  if (cnt > highest)
-    highest = cnt;
-  highest_version = last_version;
-  next;
-}
-
-END {
-  if (! highest_version) {
-    print "/* No sys_errlist/sys_nerr symbols defined on this platform.  */";
-    exit 0;
-  }
-
-  count = maxerr + 1;
-
-  if (highest < count) {
-    printf "*** errlist.c count %d vs Versions sys_errlist@%s count %d\n", \
-      count, highest_version, highest > "/dev/stderr";
-    exit 1;
-  }
-
-  lastv = "";
-  for (n = 0; n < pos; ++n) {
-    split(version[n], t, SUBSEP)
-    v = t[2];
-    gsub(/[^A-Z0-9_]/, "_", v);
-    if (lastv != "")
-      compat[lastv] = v;
-    lastv = v;