Re: RFA: Support Windows extended error numbers in safe_strerror

[Daniel Jacobowitz <drow@false.org>]

On Wed, Feb 08, 2006 at 10:07:59PM +0100, Mark Kettenis wrote:
> My dislike for this stuff is probably there because where I've been
> cleaning out much of the host-specific quirks, this MinGW support
> seems to add back a lot special tweaks, and since Windows is so
> different from Unix-like systems, there's absolutely no hope, things
> can be unified.  That, together with the reintroduction of xm.h, seems
> like a giant leap backwards to me.  I really don't like that xm.h is
> back now, since it sets a precedent.  People have used these files for
> quick hacks in the past, and the new xm.h will make it harder to tell
> people that's not acceptable.  I think there is a better approach
> though.  How about having the implementation of safe_strerror() and
> gdb_select() in mingw-hdep.c and move the (trivial) existing
> implementations of these functions to a new posix-hdep.c?

I really dislike _this_ precedent: Don't allow the existance of xm.h
because people abused it in the past.  That's what review is for,
right?

Anyway, here's a patch updated in every way I can think of to make it
less upsetting.  Is this really better?  Select to follow in the proper
thread.

-- 
Daniel Jacobowitz
CodeSourcery

2006-02-06  Daniel Jacobowitz  <dan@codesourcery.com>

	* Makefile.in (mingw-hdep.o, posix-hdep.o): New dependencies.
	(ALLDEPFILES): Add mingw-hdep.c and posix-hdep.c.
	* configure.ac: Add gdb_host_obs to CONFIG_OBS.  Set gdb_host_obs
	to posix-hdep.o by default.
	* configure: Regenerated.
	* configure.host: Document gdb_host_obs.  Add an entry for
	i[34567]86-*-mingw32*.
	* mingw-hdep.c, posix-hdep.c: New files.
	* utils.c (safe_strerror): Remove, moved to posix-hdep.o.

Index: src/gdb/Makefile.in
===================================================================
--- src.orig/gdb/Makefile.in	2006-02-09 13:28:51.000000000 -0500
+++ src/gdb/Makefile.in	2006-02-09 16:50:17.000000000 -0500
@@ -1422,6 +1422,7 @@ ALLDEPFILES = \
 	m68kbsd-nat.c m68kbsd-tdep.c \
 	m68klinux-nat.c m68klinux-tdep.c \
 	m88k-tdep.c m88kbsd-nat.c \
+	mingw-hdep.c \
 	mips-linux-nat.c mips-linux-tdep.c \
 	mips-irix-tdep.c \
 	mips-tdep.c mipsv4-nat.c \
@@ -1430,6 +1431,7 @@ ALLDEPFILES = \
 	nbsd-tdep.c obsd-tdep.c \
 	solib-osf.c \
 	somread.c solib-som.c $(HPREAD_SOURCE) \
+	posix-hdep.c \
 	ppc-sysv-tdep.c ppc-linux-nat.c ppc-linux-tdep.c \
 	ppcnbsd-nat.c ppcnbsd-tdep.c \
 	ppcobsd-nat.c ppcobsd-tdep.c \
@@ -2280,6 +2282,7 @@ memattr.o: memattr.c $(defs_h) $(command
 	$(target_h) $(value_h) $(language_h) $(gdb_string_h)
 mem-break.o: mem-break.c $(defs_h) $(symtab_h) $(breakpoint_h) $(inferior_h) \
 	$(target_h)
+mingw-hdep.o: mingw-hdep.c $(defs_h) $(gdb_string_h)
 minsyms.o: minsyms.c $(defs_h) $(gdb_string_h) $(symtab_h) $(bfd_h) \
 	$(symfile_h) $(objfiles_h) $(demangle_h) $(value_h) $(cp_abi_h)
 mips64obsd-nat.o: mips64obsd-nat.c $(defs_h) $(inferior_h) $(regcache_h) \
@@ -2375,6 +2378,7 @@ p-exp.o: p-exp.c $(defs_h) $(gdb_string_
 p-lang.o: p-lang.c $(defs_h) $(gdb_string_h) $(symtab_h) $(gdbtypes_h) \
 	$(expression_h) $(parser_defs_h) $(language_h) $(p_lang_h) \
 	$(valprint_h) $(value_h)
+posix-hdep.o: posix-hdep.c $(defs_h)
 ppc-bdm.o: ppc-bdm.c $(defs_h) $(gdbcore_h) $(gdb_string_h) $(frame_h) \
 	$(inferior_h) $(bfd_h) $(symfile_h) $(target_h) $(gdbcmd_h) \
 	$(objfiles_h) $(gdb_stabs_h) $(serial_h) $(ocd_h) $(ppc_tdep_h) \
Index: src/gdb/configure.ac
===================================================================
--- src.orig/gdb/configure.ac	2006-02-09 13:28:51.000000000 -0500
+++ src/gdb/configure.ac	2006-02-09 16:52:25.000000000 -0500
@@ -112,6 +112,10 @@ AC_DEFINE_DIR(DEBUGDIR, debugdir,
 
 AC_CONFIG_SUBDIRS(doc testsuite)
 
+# Provide defaults for some variables set by the per-host and per-target
+# configuration.
+gdb_host_obs=posix-hdep.o
+
 . $srcdir/configure.host
 
 . $srcdir/configure.tgt
@@ -1225,6 +1229,9 @@ case ${host} in
 esac	    
 AC_SUBST(WIN32LIBS)
 
+# Add any host-specific objects to GDB.
+CONFIG_OBS="${CONFIG_OBS} ${gdb_host_obs}"
+
 LIBGUI="../libgui/src/libgui.a"
 GUI_CFLAGS_X="-I${srcdir}/../libgui/src"
 AC_SUBST(LIBGUI)
Index: src/gdb/configure.host
===================================================================
--- src.orig/gdb/configure.host	2006-02-09 13:28:51.000000000 -0500
+++ src/gdb/configure.host	2006-02-09 16:52:12.000000000 -0500
@@ -7,6 +7,7 @@
 #  gdb_host_float_format	host's float floatformat, or 0
 #  gdb_host_double_format	host's double floatformat, or 0
 #  gdb_host_long_double_format	host's long double floatformat, or 0
+#  gdb_host_obs			host-specific .o files to include
 
 # Map host cpu into the config cpu subdirectory name.
 # The default is $host_cpu.
@@ -64,6 +65,9 @@ i[34567]86-*-netbsdelf* | i[34567]86-*-k
 			gdb_host=nbsdelf ;;
 i[34567]86-*-netbsd*)	gdb_host=nbsdaout ;;
 i[34567]86-*-go32*)	gdb_host=go32 ;;
+i[34567]86-*-mingw32*)	gdb_host=mingw
+			gdb_host_obs=mingw-hdep.o
+			;;
 i[34567]86-*-msdosdjgpp*) gdb_host=go32 ;;
 i[34567]86-*-linux*)	gdb_host=linux ;;
 i[34567]86-*-lynxos*)	gdb_host=i386lynx ;;
Index: src/gdb/mingw-hdep.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ src/gdb/mingw-hdep.c	2006-02-09 16:49:11.000000000 -0500
@@ -0,0 +1,71 @@
+/* Host support routines for MinGW, for GDB, the GNU debugger.
+
+   Copyright (C) 2006
+   Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
+
+#include "defs.h"
+
+#include "gdb_string.h"
+
+#include <windows.h>
+
+/* The strerror() function can return NULL for errno values that are
+   out of range.  Provide a "safe" version that always returns a
+   printable string.
+
+   The Windows runtime implementation of strerror never returns NULL,
+   but does return a useless string for anything above sys_nerr;
+   unfortunately this includes all socket-related error codes.
+   This replacement tries to find a system-provided error message.  */
+
+char *
+safe_strerror (int errnum)
+{
+  static char *buffer;
+  int len;
+
+  if (errnum >= 0 && errnum < sys_nerr)
+    return strerror (errnum);
+
+  if (buffer)
+    {
+      LocalFree (buffer);
+      buffer = NULL;
+    }
+
+  if (FormatMessage (FORMAT_MESSAGE_ALLOCATE_BUFFER
+		     | FORMAT_MESSAGE_FROM_SYSTEM,
+		     NULL, errnum,
+		     MAKELANGID (LANG_NEUTRAL, SUBLANG_DEFAULT),
+		     (LPTSTR) &buffer, 0, NULL) == 0)
+    {
+      static char buf[32];
+      xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum);
+      return buf;
+    }
+
+  /* Windows error messages end with a period and a CR-LF; strip that
+     out.  */
+  len = strlen (buffer);
+  if (len > 3 && strcmp (buffer + len - 3, ".\r\n") == 0)
+    buffer[len - 3] = '\0';
+
+  return buffer;
+}
Index: src/gdb/posix-hdep.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ src/gdb/posix-hdep.c	2006-02-09 16:47:26.000000000 -0500
@@ -0,0 +1,43 @@
+/* Host support routines for MinGW, for GDB, the GNU debugger.
+
+   Copyright (C) 2006
+   Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
+
+#include "defs.h"
+
+/* The strerror() function can return NULL for errno values that are
+   out of range.  Provide a "safe" version that always returns a
+   printable string. */
+
+char *
+safe_strerror (int errnum)
+{
+  char *msg;
+
+  msg = strerror (errnum);
+  if (msg == NULL)
+    {
+      static char buf[32];
+      xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum);
+      msg = buf;
+    }
+  return (msg);
+}
+
Index: src/gdb/utils.c
===================================================================
--- src.orig/gdb/utils.c	2006-02-07 11:11:34.000000000 -0500
+++ src/gdb/utils.c	2006-02-09 16:47:34.000000000 -0500
@@ -838,25 +838,6 @@ internal_warning (const char *file, int 
   va_end (ap);
 }
 
-/* The strerror() function can return NULL for errno values that are
-   out of range.  Provide a "safe" version that always returns a
-   printable string. */
-
-char *
-safe_strerror (int errnum)
-{
-  char *msg;
-
-  msg = strerror (errnum);
-  if (msg == NULL)
-    {
-      static char buf[32];
-      xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum);
-      msg = buf;
-    }
-  return (msg);
-}
-
 /* Print the system error message for errno, and also mention STRING
    as the file name for which the error was encountered.
    Then return to command level.  */