X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Fosabi.c;h=627b9d98151513d1af0126ae8474139c3a515350;hb=refs%2Fheads%2Fconcurrent-displaced-stepping-2020-04-01;hp=83eb767c0b731aa49739c3b0822b471b5cde472d;hpb=2ee563b53258d390d7446e90a67f465d504ae44c;p=deliverable%2Fbinutils-gdb.git

diff --git a/gdb/osabi.c b/gdb/osabi.c
index 83eb767c0b..627b9d9815 100644
--- a/gdb/osabi.c
+++ b/gdb/osabi.c
@@ -1,72 +1,141 @@
 /* OS ABI variant handling for GDB.
-   Copyright 2001, 2002 Free Software Foundation, Inc.
+
+   Copyright (C) 2001-2020 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
+   the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.
 
-   This program is distributed in the hope that it will be useful,  
+   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., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
+
 #include "osabi.h"
+#include "arch-utils.h"
+#include "gdbcmd.h"
+#include "command.h"
 
 #include "elf-bfd.h"
 
+#ifndef GDB_OSABI_DEFAULT
+#define GDB_OSABI_DEFAULT GDB_OSABI_UNKNOWN
+#endif
+
+/* State for the "set osabi" command.  */
+static enum { osabi_auto, osabi_default, osabi_user } user_osabi_state;
+static enum gdb_osabi user_selected_osabi;
+static const char *gdb_osabi_available_names[GDB_OSABI_INVALID + 3] = {
+  "auto",
+  "default",
+  "none",
+  NULL
+};
+static const char *set_osabi_string;
+
+/* Names associated with each osabi.  */
+
+struct osabi_names
+{
+  /* The "pretty" name.  */
+
+  const char *pretty;
+
+  /* The triplet regexp, or NULL if not known.  */
+
+  const char *regexp;
+};
 
 /* This table matches the indices assigned to enum gdb_osabi.  Keep
    them in sync.  */
-static const char * const gdb_osabi_names[] =
+static const struct osabi_names gdb_osabi_names[] =
 {
-  "<unknown>",
-
-  "SVR4",
-  "GNU/Hurd",
-  "Solaris",
-  "OSF/1",
-  "GNU/Linux",
-  "FreeBSD a.out",
-  "FreeBSD ELF",
-  "NetBSD a.out",
-  "NetBSD ELF",
-  "Windows CE",
-  "DJGPP",
-  "NetWare",
-  "Irix",
-  "LynxOS",
-
-  "ARM EABI v1",
-  "ARM EABI v2",
-  "ARM APCS",
-
-  "<invalid>"
+  { "unknown", NULL },
+  { "none", NULL },
+
+  { "SVR4", NULL },
+  { "GNU/Hurd", NULL },
+  { "Solaris", NULL },
+  { "GNU/Linux", "linux(-gnu[^-]*)?" },
+  { "FreeBSD", NULL },
+  { "NetBSD", NULL },
+  { "OpenBSD", NULL },
+  { "WindowsCE", NULL },
+  { "DJGPP", NULL },
+  { "QNX-Neutrino", NULL },
+  { "Cygwin", NULL },
+  { "Windows", NULL },
+  { "AIX", NULL },
+  { "DICOS", NULL },
+  { "Darwin", NULL },
+  { "Symbian", NULL },
+  { "OpenVMS", NULL },
+  { "LynxOS178", NULL },
+  { "Newlib", NULL },
+  { "SDE", NULL },
+  { "PikeOS", NULL },
+
+  { "<invalid>", NULL }
 };
 
 const char *
 gdbarch_osabi_name (enum gdb_osabi osabi)
 {
   if (osabi >= GDB_OSABI_UNKNOWN && osabi < GDB_OSABI_INVALID)
-    return gdb_osabi_names[osabi];
+    return gdb_osabi_names[osabi].pretty;
 
-  return gdb_osabi_names[GDB_OSABI_INVALID];
+  return gdb_osabi_names[GDB_OSABI_INVALID].pretty;
+}
+
+/* See osabi.h.  */
+
+const char *
+osabi_triplet_regexp (enum gdb_osabi osabi)
+{
+  if (osabi >= GDB_OSABI_UNKNOWN && osabi < GDB_OSABI_INVALID)
+    return gdb_osabi_names[osabi].regexp;
+
+  return gdb_osabi_names[GDB_OSABI_INVALID].regexp;
+}
+
+/* Lookup the OS ABI corresponding to the specified target description
+   string.  */
+
+enum gdb_osabi
+osabi_from_tdesc_string (const char *name)
+{
+  int i;
+
+  for (i = 0; i < ARRAY_SIZE (gdb_osabi_names); i++)
+    if (strcmp (name, gdb_osabi_names[i].pretty) == 0)
+      {
+	/* See note above: the name table matches the indices assigned
+	   to enum gdb_osabi.  */
+	enum gdb_osabi osabi = (enum gdb_osabi) i;
+
+	if (osabi == GDB_OSABI_INVALID)
+	  return GDB_OSABI_UNKNOWN;
+	else
+	  return osabi;
+      }
+
+  return GDB_OSABI_UNKNOWN;
 }
 
 /* Handler for a given architecture/OS ABI pair.  There should be only
    one handler for a given OS ABI each architecture family.  */
-struct gdb_osabi_handler  
+struct gdb_osabi_handler
 {
   struct gdb_osabi_handler *next;
-  enum bfd_architecture arch;
+  const struct bfd_arch_info *arch_info;
   enum gdb_osabi osabi;
   void (*init_osabi)(struct gdbarch_info, struct gdbarch *);
 };
@@ -74,53 +143,67 @@ struct gdb_osabi_handler
 static struct gdb_osabi_handler *gdb_osabi_handler_list;
 
 void
-gdbarch_register_osabi (enum bfd_architecture arch, enum gdb_osabi osabi,
-                        void (*init_osabi)(struct gdbarch_info,
+gdbarch_register_osabi (enum bfd_architecture arch, unsigned long machine,
+			enum gdb_osabi osabi,
+			void (*init_osabi)(struct gdbarch_info,
 					   struct gdbarch *))
 {
   struct gdb_osabi_handler **handler_p;
+  const struct bfd_arch_info *arch_info = bfd_lookup_arch (arch, machine);
+  const char **name_ptr;
 
   /* Registering an OS ABI handler for "unknown" is not allowed.  */
   if (osabi == GDB_OSABI_UNKNOWN)
     {
       internal_error
 	(__FILE__, __LINE__,
-	 "gdbarch_register_osabi: An attempt to register a handler for "
-         "OS ABI \"%s\" for architecture %s was made.  The handler will "
-	 "not be registered",
+	 _("gdbarch_register_osabi: An attempt to register a handler for "
+	 "OS ABI \"%s\" for architecture %s was made.  The handler will "
+	 "not be registered"),
 	 gdbarch_osabi_name (osabi),
-	 bfd_printable_arch_mach (arch, 0));
+	 bfd_printable_arch_mach (arch, machine));
       return;
     }
 
+  gdb_assert (arch_info);
+
   for (handler_p = &gdb_osabi_handler_list; *handler_p != NULL;
        handler_p = &(*handler_p)->next)
     {
-      if ((*handler_p)->arch == arch
+      if ((*handler_p)->arch_info == arch_info
 	  && (*handler_p)->osabi == osabi)
 	{
 	  internal_error
 	    (__FILE__, __LINE__,
-	     "gdbarch_register_osabi: A handler for OS ABI \"%s\" "
-	     "has already been registered for architecture %s",
+	     _("gdbarch_register_osabi: A handler for OS ABI \"%s\" "
+	     "has already been registered for architecture %s"),
 	     gdbarch_osabi_name (osabi),
-	     bfd_printable_arch_mach (arch, 0));
+	     arch_info->printable_name);
 	  /* If user wants to continue, override previous definition.  */
 	  (*handler_p)->init_osabi = init_osabi;
 	  return;
 	}
     }
 
-  (*handler_p)
-    = (struct gdb_osabi_handler *) xmalloc (sizeof (struct gdb_osabi_handler));
+  (*handler_p) = XNEW (struct gdb_osabi_handler);
   (*handler_p)->next = NULL;
-  (*handler_p)->arch = arch;
+  (*handler_p)->arch_info = arch_info;
   (*handler_p)->osabi = osabi;
   (*handler_p)->init_osabi = init_osabi;
+
+  /* Add this OS ABI to the list of enum values for "set osabi", if it isn't
+     already there.  */
+  for (name_ptr = gdb_osabi_available_names; *name_ptr; name_ptr ++)
+    {
+      if (*name_ptr == gdbarch_osabi_name (osabi))
+	return;
+    }
+  *name_ptr++ = gdbarch_osabi_name (osabi);
+  *name_ptr = NULL;
 }
 
 
-/* Sniffer to find the OS ABI for a given file's architecture and flavour. 
+/* Sniffer to find the OS ABI for a given file's architecture and flavour.
    It is legal to have multiple sniffers for each arch/flavour pair, to
    disambiguate one OS's a.out from another, for example.  The first sniffer
    to return something other than GDB_OSABI_UNKNOWN wins, so a sniffer should
@@ -137,13 +220,12 @@ static struct gdb_osabi_sniffer *gdb_osabi_sniffer_list;
 
 void
 gdbarch_register_osabi_sniffer (enum bfd_architecture arch,
-                                enum bfd_flavour flavour,
+				enum bfd_flavour flavour,
 				enum gdb_osabi (*sniffer_fn)(bfd *))
 {
   struct gdb_osabi_sniffer *sniffer;
 
-  sniffer =
-    (struct gdb_osabi_sniffer *) xmalloc (sizeof (struct gdb_osabi_sniffer));
+  sniffer = XNEW (struct gdb_osabi_sniffer);
   sniffer->arch = arch;
   sniffer->flavour = flavour;
   sniffer->sniffer = sniffer_fn;
@@ -160,6 +242,16 @@ gdbarch_lookup_osabi (bfd *abfd)
   enum gdb_osabi osabi, match;
   int match_specific;
 
+  /* If we aren't in "auto" mode, return the specified OS ABI.  */
+  if (user_osabi_state == osabi_user)
+    return user_selected_osabi;
+
+  /* If we don't have a binary, just return unknown.  The caller may
+     have other sources the OSABI can be extracted from, e.g., the
+     target description.  */
+  if (abfd == NULL)
+    return GDB_OSABI_UNKNOWN;
+
   match = GDB_OSABI_UNKNOWN;
   match_specific = 0;
 
@@ -175,8 +267,8 @@ gdbarch_lookup_osabi (bfd *abfd)
 	    {
 	      internal_error
 		(__FILE__, __LINE__,
-		 "gdbarch_lookup_osabi: invalid OS ABI (%d) from sniffer "
-		 "for architecture %s flavour %d",
+		 _("gdbarch_lookup_osabi: invalid OS ABI (%d) from sniffer "
+		 "for architecture %s flavour %d"),
 		 (int) osabi,
 		 bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
 		 (int) bfd_get_flavour (abfd));
@@ -193,15 +285,15 @@ gdbarch_lookup_osabi (bfd *abfd)
 		   || (!match_specific && sniffer->arch == bfd_arch_unknown))
 		    {
 		      internal_error
-		        (__FILE__, __LINE__,
-		         "gdbarch_lookup_osabi: multiple %sspecific OS ABI "
+			(__FILE__, __LINE__,
+			 _("gdbarch_lookup_osabi: multiple %sspecific OS ABI "
 			 "match for architecture %s flavour %d: first "
-			 "match \"%s\", second match \"%s\"",
+			 "match \"%s\", second match \"%s\""),
 			 match_specific ? "" : "non-",
-		         bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
-		         (int) bfd_get_flavour (abfd),
-		         gdbarch_osabi_name (match),
-		         gdbarch_osabi_name (osabi));
+			 bfd_printable_arch_mach (bfd_get_arch (abfd), 0),
+			 (int) bfd_get_flavour (abfd),
+			 gdbarch_osabi_name (match),
+			 gdbarch_osabi_name (osabi));
 		    }
 		  else if (sniffer->arch != bfd_arch_unknown)
 		    {
@@ -222,143 +314,224 @@ gdbarch_lookup_osabi (bfd *abfd)
   return match;
 }
 
+
+/* Return non-zero if architecture A can run code written for
+   architecture B.  */
+static int
+can_run_code_for (const struct bfd_arch_info *a, const struct bfd_arch_info *b)
+{
+  /* BFD's 'A->compatible (A, B)' functions return zero if A and B are
+     incompatible.  But if they are compatible, it returns the 'more
+     featureful' of the two arches.  That is, if A can run code
+     written for B, but B can't run code written for A, then it'll
+     return A.
+
+     struct bfd_arch_info objects are singletons: that is, there's
+     supposed to be exactly one instance for a given machine.  So you
+     can tell whether two are equivalent by comparing pointers.  */
+  return (a == b || a->compatible (a, b) == a);
+}
+
+
 void
-gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch,
-                    enum gdb_osabi osabi)
+gdbarch_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
   struct gdb_osabi_handler *handler;
-  bfd *abfd = info.abfd;
-  const struct bfd_arch_info *arch_info = gdbarch_bfd_arch_info (gdbarch);
 
-  if (osabi == GDB_OSABI_UNKNOWN)
-    {
-      /* Don't complain about an unknown OSABI.  Assume the user knows
-         what they are doing.  */
-      return;
-    }
+  gdb_assert (info.osabi != GDB_OSABI_UNKNOWN);
 
   for (handler = gdb_osabi_handler_list; handler != NULL;
        handler = handler->next)
     {
-      if (handler->arch == bfd_get_arch (abfd)
-	  && handler->osabi == osabi)
+      if (handler->osabi != info.osabi)
+	continue;
+
+      /* If the architecture described by ARCH_INFO can run code for
+	 the architecture we registered the handler for, then the
+	 handler is applicable.  Note, though, that if the handler is
+	 for an architecture that is a superset of ARCH_INFO, we can't
+	 use that --- it would be perfectly correct for it to install
+	 gdbarch methods that refer to registers / instructions /
+	 other facilities ARCH_INFO doesn't have.
+
+	 NOTE: kettenis/20021027: There may be more than one machine
+	 type that is compatible with the desired machine type.  Right
+	 now we simply return the first match, which is fine for now.
+	 However, we might want to do something smarter in the future.  */
+      /* NOTE: cagney/2003-10-23: The code for "a can_run_code_for b"
+	 is implemented using BFD's compatible method (a->compatible
+	 (b) == a -- the lowest common denominator between a and b is
+	 a).  That method's definition of compatible may not be as you
+	 expect.  For instance the test "amd64 can run code for i386"
+	 (or more generally "64-bit ISA can run code for the 32-bit
+	 ISA").  BFD doesn't normally consider 32-bit and 64-bit
+	 "compatible" so it doesn't succeed.  */
+      if (can_run_code_for (info.bfd_arch_info, handler->arch_info))
 	{
 	  (*handler->init_osabi) (info, gdbarch);
 	  return;
 	}
     }
 
-  /* We assume that if GDB_MULTI_ARCH is less than GDB_MULTI_ARCH_TM
-     that an ABI variant can be supported by overriding definitions in
-     the tm-file.  */
-  if (GDB_MULTI_ARCH > GDB_MULTI_ARCH_PARTIAL)
-    fprintf_filtered
-      (gdb_stderr,
-       "A handler for the OS ABI \"%s\" is not built into this "
-       "configuration of GDB.  "
-       "Attempting to continue with the default %s settings",
-       gdbarch_osabi_name (osabi),
-       bfd_printable_arch_mach (arch_info->arch, arch_info->mach));
+  if (info.osabi == GDB_OSABI_NONE)
+    {
+      /* Don't complain about no OSABI.  Assume the user knows
+	 what they are doing.  */
+      return;
+    }
+
+  warning
+    ("A handler for the OS ABI \"%s\" is not built into this configuration\n"
+     "of GDB.  Attempting to continue with the default %s settings.\n",
+     gdbarch_osabi_name (info.osabi),
+     info.bfd_arch_info->printable_name);
 }
 
+/* Limit on the amount of data to be read.  */
+#define MAX_NOTESZ	128
+
+/* Return non-zero if NOTE matches NAME, DESCSZ and TYPE.  If
+   *SECTSIZE is non-zero, then this reads that many bytes from
+   the start of the section and clears *SECTSIZE.  */
+
+static int
+check_note (bfd *abfd, asection *sect, char *note, unsigned int *sectsize,
+	    const char *name, unsigned long descsz, unsigned long type)
+{
+  unsigned long notesz;
+
+  if (*sectsize)
+    {
+      if (!bfd_get_section_contents (abfd, sect, note, 0, *sectsize))
+	return 0;
+      *sectsize = 0;
+    }
+
+  /* Calculate the size of this note.  */
+  notesz = strlen (name) + 1;
+  notesz = ((notesz + 3) & ~3);
+  notesz += descsz;
+  notesz = ((notesz + 3) & ~3);
+
+  /* If this assertion triggers, increase MAX_NOTESZ.  */
+  gdb_assert (notesz <= MAX_NOTESZ);
+
+  /* Check whether SECT is big enough to contain the complete note.  */
+  if (notesz > bfd_section_size (sect))
+    return 0;
+
+  /* Check the note name.  */
+  if (bfd_h_get_32 (abfd, note) != (strlen (name) + 1)
+      || strcmp (note + 12, name) != 0)
+    return 0;
+
+  /* Check the descriptor size.  */
+  if (bfd_h_get_32 (abfd, note + 4) != descsz)
+    return 0;
+
+  /* Check the note type.  */
+  if (bfd_h_get_32 (abfd, note + 8) != type)
+    return 0;
+
+  return 1;
+}
 
 /* Generic sniffer for ELF flavoured files.  */
 
 void
 generic_elf_osabi_sniff_abi_tag_sections (bfd *abfd, asection *sect, void *obj)
 {
-  enum gdb_osabi *os_ident_ptr = obj;
+  enum gdb_osabi *osabi = (enum gdb_osabi *) obj;
   const char *name;
   unsigned int sectsize;
+  char *note;
 
-  name = bfd_get_section_name (abfd, sect);
-  sectsize = bfd_section_size (abfd, sect);
-
-  /* .note.ABI-tag notes, used by GNU/Linux and FreeBSD.  */
-  if (strcmp (name, ".note.ABI-tag") == 0 && sectsize > 0)
-    {
-      unsigned int name_length, data_length, note_type;
-      char *note;
-
-      /* If the section is larger than this, it's probably not what we are
-	 looking for.  */
-      if (sectsize > 128)
-	sectsize = 128;
-
-      note = alloca (sectsize);
+  name = bfd_section_name (sect);
+  sectsize = bfd_section_size (sect);
 
-      bfd_get_section_contents (abfd, sect, note,
-				(file_ptr) 0, (bfd_size_type) sectsize);
+  /* Limit the amount of data to read.  */
+  if (sectsize > MAX_NOTESZ)
+    sectsize = MAX_NOTESZ;
 
-      name_length = bfd_h_get_32 (abfd, note);
-      data_length = bfd_h_get_32 (abfd, note + 4);
-      note_type   = bfd_h_get_32 (abfd, note + 8);
+  /* We lazily read the section data here.  Since we use
+     BFD_DECOMPRESS, we can't use bfd_get_section_contents on a
+     compressed section.  But, since note sections are not compressed,
+     deferring the reading until we recognize the section avoids any
+     error.  */
+  note = (char *) alloca (sectsize);
 
-      if (name_length == 4 && data_length == 16 && note_type == NT_GNU_ABI_TAG
-	  && strcmp (note + 12, "GNU") == 0)
+  /* .note.ABI-tag notes, used by GNU/Linux and FreeBSD.  */
+  if (strcmp (name, ".note.ABI-tag") == 0)
+    {
+      /* GNU.  */
+      if (check_note (abfd, sect, note, &sectsize, "GNU", 16, NT_GNU_ABI_TAG))
 	{
-	  int os_number = bfd_h_get_32 (abfd, note + 16);
+	  unsigned int abi_tag = bfd_h_get_32 (abfd, note + 16);
 
-	  switch (os_number)
+	  switch (abi_tag)
 	    {
 	    case GNU_ABI_TAG_LINUX:
-	      *os_ident_ptr = GDB_OSABI_LINUX;
+	      *osabi = GDB_OSABI_LINUX;
 	      break;
 
 	    case GNU_ABI_TAG_HURD:
-	      *os_ident_ptr = GDB_OSABI_HURD;
+	      *osabi = GDB_OSABI_HURD;
 	      break;
 
 	    case GNU_ABI_TAG_SOLARIS:
-	      *os_ident_ptr = GDB_OSABI_SOLARIS;
+	      *osabi = GDB_OSABI_SOLARIS;
+	      break;
+
+	    case GNU_ABI_TAG_FREEBSD:
+	      *osabi = GDB_OSABI_FREEBSD;
+	      break;
+
+	    case GNU_ABI_TAG_NETBSD:
+	      *osabi = GDB_OSABI_NETBSD;
 	      break;
 
 	    default:
-	      internal_error
-		(__FILE__, __LINE__,
-		 "generic_elf_osabi_sniff_abi_tag_sections: unknown OS number %d",
-		 os_number);
+	      warning (_("GNU ABI tag value %u unrecognized."), abi_tag);
+	      break;
 	    }
 	  return;
 	}
-      else if (name_length == 8 && data_length == 4
-	       && note_type == NT_FREEBSD_ABI_TAG
-	       && strcmp (note + 12, "FreeBSD") == 0)
+
+      /* FreeBSD.  */
+      if (check_note (abfd, sect, note, &sectsize, "FreeBSD", 4,
+		      NT_FREEBSD_ABI_TAG))
 	{
-	  /* XXX Should we check the version here?  Probably not
-	     necessary yet.  */
-	  *os_ident_ptr = GDB_OSABI_FREEBSD_ELF;
+	  /* There is no need to check the version yet.  */
+	  *osabi = GDB_OSABI_FREEBSD;
+	  return;
 	}
+
       return;
     }
 
   /* .note.netbsd.ident notes, used by NetBSD.  */
-  if (strcmp (name, ".note.netbsd.ident") == 0 && sectsize > 0)
+  if (strcmp (name, ".note.netbsd.ident") == 0
+      && check_note (abfd, sect, note, &sectsize, "NetBSD", 4, NT_NETBSD_IDENT))
     {
-      unsigned int name_length, data_length, note_type;
-      char *note;
-
-      /* If the section is larger than this, it's probably not what we are
-	 looking for.  */
-      if (sectsize > 128) 
-	sectsize = 128;
-
-      note = alloca (sectsize);
+      /* There is no need to check the version yet.  */
+      *osabi = GDB_OSABI_NETBSD;
+      return;
+    }
 
-      bfd_get_section_contents (abfd, sect, note,
-				(file_ptr) 0, (bfd_size_type) sectsize);
-      
-      name_length = bfd_h_get_32 (abfd, note);
-      data_length = bfd_h_get_32 (abfd, note + 4);
-      note_type   = bfd_h_get_32 (abfd, note + 8);
+  /* .note.openbsd.ident notes, used by OpenBSD.  */
+  if (strcmp (name, ".note.openbsd.ident") == 0
+      && check_note (abfd, sect, note, &sectsize, "OpenBSD", 4,
+		     NT_OPENBSD_IDENT))
+    {
+      /* There is no need to check the version yet.  */
+      *osabi = GDB_OSABI_OPENBSD;
+      return;
+    }
 
-      if (name_length == 7 && data_length == 4 && note_type == NT_NETBSD_IDENT
-	  && strcmp (note + 12, "NetBSD") == 0)
-	{
-	  /* XXX Should we check the version here?  Probably not
-	     necessary yet.  */
-	  *os_ident_ptr = GDB_OSABI_NETBSD_ELF;
-	}
+  /* .note.netbsdcore.procinfo notes, used by NetBSD.  */
+  if (strcmp (name, ".note.netbsdcore.procinfo") == 0)
+    {
+      *osabi = GDB_OSABI_NETBSD;
       return;
     }
 }
@@ -374,59 +547,133 @@ generic_elf_osabi_sniffer (bfd *abfd)
   switch (elfosabi)
     {
     case ELFOSABI_NONE:
-      /* When elfosabi is ELFOSABI_NONE (0), then the ELF structures in the
-         file are conforming to the base specification for that machine
-	 (there are no OS-specific extensions).  In order to determine the
-	 real OS in use we must look for OS notes that have been added.  */
+    case ELFOSABI_GNU:
+    case ELFOSABI_HPUX:
+      /* When the EI_OSABI field in the ELF header is ELFOSABI_NONE
+	 (0), then the ELF structures in the file are conforming to
+	 the base specification for that machine (there are no
+	 OS-specific extensions).  In order to determine the real OS
+	 in use, we must look for OS-specific notes.
+
+	 The same applies for ELFOSABI_GNU: this can mean GNU/Hurd,
+	 GNU/Linux, and possibly more.  */
+
+      /* And likewise ELFOSABI_HPUX.  For some reason the default
+	 value for the EI_OSABI field is ELFOSABI_HPUX for all PA-RISC
+	 targets (with the exception of GNU/Linux).  */
       bfd_map_over_sections (abfd,
 			     generic_elf_osabi_sniff_abi_tag_sections,
 			     &osabi);
       break;
 
     case ELFOSABI_FREEBSD:
-      osabi = GDB_OSABI_FREEBSD_ELF;
+      osabi = GDB_OSABI_FREEBSD;
       break;
 
     case ELFOSABI_NETBSD:
-      osabi = GDB_OSABI_NETBSD_ELF;
-      break;
-
-    case ELFOSABI_LINUX:
-      osabi = GDB_OSABI_LINUX;
-      break;
-
-    case ELFOSABI_HURD:
-      osabi = GDB_OSABI_HURD;
+      osabi = GDB_OSABI_NETBSD;
       break;
 
     case ELFOSABI_SOLARIS:
       osabi = GDB_OSABI_SOLARIS;
       break;
+
+    case ELFOSABI_OPENVMS:
+      osabi = GDB_OSABI_OPENVMS;
+      break;
     }
 
   if (osabi == GDB_OSABI_UNKNOWN)
     {
       /* The FreeBSD folks have been naughty; they stored the string
-         "FreeBSD" in the padding of the e_ident field of the ELF
-         header to "brand" their ELF binaries in FreeBSD 3.x.  */
-      if (strcmp (&elf_elfheader (abfd)->e_ident[8], "FreeBSD") == 0)
-	osabi = GDB_OSABI_FREEBSD_ELF;
+	 "FreeBSD" in the padding of the e_ident field of the ELF
+	 header to "brand" their ELF binaries in FreeBSD 3.x.  */
+      if (memcmp (&elf_elfheader (abfd)->e_ident[8],
+		  "FreeBSD", sizeof ("FreeBSD")) == 0)
+	osabi = GDB_OSABI_FREEBSD;
     }
 
   return osabi;
 }
 
+static void
+set_osabi (const char *args, int from_tty, struct cmd_list_element *c)
+{
+  struct gdbarch_info info;
+
+  if (strcmp (set_osabi_string, "auto") == 0)
+    user_osabi_state = osabi_auto;
+  else if (strcmp (set_osabi_string, "default") == 0)
+    {
+      user_selected_osabi = GDB_OSABI_DEFAULT;
+      user_osabi_state = osabi_user;
+    }
+  else
+    {
+      int i;
 
+      for (i = 1; i < GDB_OSABI_INVALID; i++)
+        {
+	  enum gdb_osabi osabi = (enum gdb_osabi) i;
+
+	  if (strcmp (set_osabi_string, gdbarch_osabi_name (osabi)) == 0)
+	    {
+	      user_selected_osabi = osabi;
+	      user_osabi_state = osabi_user;
+	      break;
+	    }
+	}
+      if (i == GDB_OSABI_INVALID)
+	internal_error (__FILE__, __LINE__,
+			_("Invalid OS ABI \"%s\" passed to command handler."),
+			set_osabi_string);
+    }
+
+  /* NOTE: At some point (true multiple architectures) we'll need to be more
+     graceful here.  */
+  gdbarch_info_init (&info);
+  if (! gdbarch_update_p (info))
+    internal_error (__FILE__, __LINE__, _("Updating OS ABI failed."));
+}
+
+static void
+show_osabi (struct ui_file *file, int from_tty, struct cmd_list_element *c,
+	    const char *value)
+{
+  if (user_osabi_state == osabi_auto)
+    fprintf_filtered (file,
+		      _("The current OS ABI is \"auto\" "
+			"(currently \"%s\").\n"),
+		      gdbarch_osabi_name (gdbarch_osabi (get_current_arch ())));
+  else
+    fprintf_filtered (file, _("The current OS ABI is \"%s\".\n"),
+		      gdbarch_osabi_name (user_selected_osabi));
+
+  if (GDB_OSABI_DEFAULT != GDB_OSABI_UNKNOWN)
+    fprintf_filtered (file, _("The default OS ABI is \"%s\".\n"),
+		      gdbarch_osabi_name (GDB_OSABI_DEFAULT));
+}
+
+void _initialize_gdb_osabi ();
 void
-_initialize_gdb_osabi (void)
+_initialize_gdb_osabi ()
 {
-  if (strcmp (gdb_osabi_names[GDB_OSABI_INVALID], "<invalid>") != 0)
+  if (strcmp (gdb_osabi_names[GDB_OSABI_INVALID].pretty, "<invalid>") != 0)
     internal_error
       (__FILE__, __LINE__,
-       "_initialize_gdb_osabi: gdb_osabi_names[] is inconsistent");
+       _("_initialize_gdb_osabi: gdb_osabi_names[] is inconsistent"));
 
   /* Register a generic sniffer for ELF flavoured files.  */
   gdbarch_register_osabi_sniffer (bfd_arch_unknown,
 				  bfd_target_elf_flavour,
 				  generic_elf_osabi_sniffer);
+
+  /* Register the "set osabi" command.  */
+  add_setshow_enum_cmd ("osabi", class_support, gdb_osabi_available_names,
+			&set_osabi_string,
+			_("Set OS ABI of target."),
+			_("Show OS ABI of target."),
+			NULL, set_osabi, show_osabi,
+			&setlist, &showlist);
+  user_osabi_state = osabi_auto;
 }