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>

4 files changed, 101 insertions, 14 deletions

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()