[rfc/rfa] Retrieve libraries from remote target

["Ulrich Weigand" <uweigand at de dot ibm dot com>]

Hello,

here is an updated version of the patch to have GDB automatically retrieve
shared libraries from the remote target:
http://sourceware.org/ml/gdb-patches/2008-05/msg00287.html

This version should address all comments brought up by Eli, and also has
the corresponding documentation updates.  It also fixes a problem pointed
out by Dan (behaviour of remote BFDs still open when the target connection
is shut down).


This patch requires the "target_gdbarch" patch I just posted as a separate
message.  The reason for this is the following code in gdbarch_find_by_info:

  /* Save the previously selected architecture, setting the global to
     NULL.  This stops things like gdbarch->init() trying to use the
     previous architecture's configuration.  The previous architecture
     may not even be of the same architecture family.  The most recent
     architecture of the same family is found at the head of the
     rego->arches list.  */
  struct gdbarch *old_gdbarch = current_gdbarch;
  current_gdbarch = NULL;

  /* Find the specified architecture.  */
  new_gdbarch = find_arch_by_info (info);

  /* Restore the existing architecture.  */
  gdb_assert (current_gdbarch == NULL);
  current_gdbarch = old_gdbarch;


This causes "current_gdbarch" to be NULL while find_arch_by_info is running.
However, find_arch_by_info may be issuing BFD operations (e.g. to run OSABI
sniffers).  With this patch, those BFD operations will invoke the remote
target -- which requires accessing current_gdbarch to find its state data
(get_remote_arch_state).

The "target_gdbarch" patch fixes this by having remote.c use the new
target_gdbarch variable instead, which is *not* reset while running
gdbarch_find_by_info.


Tested with no regressions on powerpc-linux and powerpc64-linux.  I've also
successfully tested a version configured with --with-sysroot=remote: against
the local gdbserver target on powerpc-linux and powerpc64-linux.

OK for mainline?

Bye,
Ulrich


ChangeLog:

	* remote.h (remote_filename_p, remote_bfd_open): Add prototypes.
	* remote.c (remote_bfd_iovec_open, remote_bfd_iovec_close,
	remote_bfd_iovec_pread, remote_bfd_iovec_stat, remote_filename_p,
	remote_bfd_open): New functions.
	(remote_hostio_send_command): Fail safely if remote connection
	is not set up.

	* solist.h (solib_open): Remove prototype.
	(solib_bfd_open): Add prototype.
	* solib.c: Include "remote.h".
	(solib_open): Remove, replace by ...
	(solib_bfd_open): ... this new function.  Handle remote BFDs.
	(solib_map_sections): Replace solib_open by solib_bfd_open.
	* solib-frv.c: Include "exceptions.h".
	(enable_break2): Replace solib_open by solib_bfd_open.
	* solib-svr4.c: Include "exceptions.h".
	(enable_break): Replace solib_open by solib_bfd_open.

	* symfile.c: Include "remote.h".
	(build_id_verify): Handle remote BFDs.
	(separate_debug_file_exists): Use BFD to access file.  Handle
	remote BFDs.
	(symfile_bfd_open): Handle remote BFDs.
	(reread_symbols): Handle remote BFDs.

	* NEWS: Mention "remote:" argument prefix to "set sysroot".

doc/ChangeLog:

	* gdb.texinfo (Commands to Specify Files): Document "remote:"
	argument prefix to "set sysroot".


diff -urNp gdb-orig/gdb/doc/gdb.texinfo gdb-head/gdb/doc/gdb.texinfo
--- gdb-orig/gdb/doc/gdb.texinfo	2008-08-12 19:13:16.000000000 +0200
+++ gdb-head/gdb/doc/gdb.texinfo	2008-08-13 19:44:21.712551354 +0200
@@ -12595,8 +12595,11 @@ library events happen.
 @end table
 
 Shared libraries are also supported in many cross or remote debugging
-configurations.  A copy of the target's libraries need to be present on the
-host system; they need to be the same as the target libraries, although the
+configurations.  GDB needs to have access to the target's libraries;
+this can be accomplished either by providing copies of the libraries
+on the host system, or by asking GDB to automatically retrieve the
+libraries from the target.  If copies of the target libraries are
+provided, they need to be the same as the target libraries, although the
 copies on the target can be stripped as long as the copies on the host are
 not.
 
@@ -12620,6 +12623,15 @@ libraries, they need to be laid out in t
 the target, with e.g.@: a @file{/lib} and @file{/usr/lib} hierarchy
 under @var{path}.
 
+If @var{path} starts with the sequence @file{remote:}, GDB will 
+retrieve the target libraries from the remote system.  This is only
+supported when using a remote target that supports the @code{remote get}
+command.  The part of @var{path} following the initial @file{remote:}
+(if present) is used as system root prefix on the remote file system.
+@footnote{If you want to specify a local system root using a directory
+that happens to be named @file{remote:}, you need to use some equivalent
+variant of the name like @file{./remote:}.}
+
 The @code{set solib-absolute-prefix} command is an alias for @code{set
 sysroot}.
 
diff -urNp gdb-orig/gdb/NEWS gdb-head/gdb/NEWS
--- gdb-orig/gdb/NEWS	2008-08-12 19:13:15.000000000 +0200
+++ gdb-head/gdb/NEWS	2008-08-13 19:44:21.761544338 +0200
@@ -3,6 +3,10 @@
 
 *** Changes since GDB 6.8
 
+* GDB now supports automatically retrieving shared library files from remote
+targets by using the `remote:' prefix on a system root path specified via
+the `set setroot' command or the `--with-sysroot' configure option.
+
 * Commands `set debug-file-directory', `set solib-search-path' and `set args'
 now complete on file names.
 
diff -urNp gdb-orig/gdb/remote.c gdb-head/gdb/remote.c
--- gdb-orig/gdb/remote.c	2008-08-13 19:43:45.193195268 +0200
+++ gdb-head/gdb/remote.c	2008-08-13 20:19:49.160978805 +0200
@@ -6695,7 +6695,8 @@ remote_hostio_send_command (int command_
   int ret, bytes_read;
   char *attachment_tmp;
 
-  if (remote_protocol_packets[which_packet].support == PACKET_DISABLE)
+  if (!remote_desc
+      || remote_protocol_packets[which_packet].support == PACKET_DISABLE)
     {
       *remote_errno = FILEIO_ENOSYS;
       return -1;
@@ -6959,6 +6960,97 @@ remote_hostio_close_cleanup (void *opaqu
   remote_hostio_close (fd, &remote_errno);
 }
 
+
+static void *
+remote_bfd_iovec_open (struct bfd *abfd, void *open_closure)
+{
+  const char *filename = bfd_get_filename (abfd);
+  int fd, remote_errno;
+  int *stream;
+
+  gdb_assert (remote_filename_p (filename));
+
+  fd = remote_hostio_open (filename + 7, FILEIO_O_RDONLY, 0, &remote_errno);
+  if (fd == -1)
+    {
+      errno = remote_fileio_errno_to_host (remote_errno);
+      bfd_set_error (bfd_error_system_call);
+      return NULL;
+    }
+
+  stream = xmalloc (sizeof (int));
+  *stream = fd;
+  return stream;
+}
+
+static int
+remote_bfd_iovec_close (struct bfd *abfd, void *stream)
+{
+  int fd = *(int *)stream;
+  int remote_errno;
+
+  xfree (stream);
+
+  /* Ignore errors on close; these may happen if the remote
+     connection was already torn down.  */
+  remote_hostio_close (fd, &remote_errno);
+
+  return 1;
+}
+
+static file_ptr
+remote_bfd_iovec_pread (struct bfd *abfd, void *stream, void *buf,
+			file_ptr nbytes, file_ptr offset)
+{
+  int fd = *(int *)stream;
+  int remote_errno;
+  file_ptr pos, bytes;
+
+  pos = 0;
+  while (nbytes > pos)
+    {
+      bytes = remote_hostio_pread (fd, (char *)buf + pos, nbytes - pos,
+				   offset + pos, &remote_errno);
+      if (bytes == 0)
+        /* Success, but no bytes, means end-of-file.  */
+        break;
+      if (bytes == -1)
+	{
+	  errno = remote_fileio_errno_to_host (remote_errno);
+	  bfd_set_error (bfd_error_system_call);
+	  return -1;
+	}
+
+      pos += bytes;
+    }
+
+  return pos;
+}
+
+static int
+remote_bfd_iovec_stat (struct bfd *abfd, void *stream, struct stat *sb)
+{
+  /* FIXME: We should probably implement remote_hostio_stat.  */
+  sb->st_size = INT_MAX;
+  return 0;
+}
+
+int
+remote_filename_p (const char *filename)
+{
+  return strncmp (filename, "remote:", 7) == 0;
+}
+
+bfd *
+remote_bfd_open (const char *remote_file, const char *target)
+{
+  return bfd_openr_iovec (remote_file, target,
+			  remote_bfd_iovec_open, NULL,
+			  remote_bfd_iovec_pread,
+			  remote_bfd_iovec_close,
+			  remote_bfd_iovec_stat);
+}
+
 void
 remote_file_put (const char *local_file, const char *remote_file, int from_tty)
 {
diff -urNp gdb-orig/gdb/remote.h gdb-head/gdb/remote.h
--- gdb-orig/gdb/remote.h	2008-05-09 21:16:06.000000000 +0200
+++ gdb-head/gdb/remote.h	2008-08-13 19:44:21.865529447 +0200
@@ -73,4 +73,8 @@ void remote_file_get (const char *remote
 		      int from_tty);
 void remote_file_delete (const char *remote_file, int from_tty);
 
+bfd *remote_bfd_open (const char *remote_file, const char *target);
+
+int remote_filename_p (const char *filename);
+
 #endif
diff -urNp gdb-orig/gdb/solib.c gdb-head/gdb/solib.c
--- gdb-orig/gdb/solib.c	2008-08-13 19:43:45.236189111 +0200
+++ gdb-head/gdb/solib.c	2008-08-13 19:44:21.871528587 +0200
@@ -44,6 +44,7 @@
 #include "solist.h"
 #include "observer.h"
 #include "readline/readline.h"
+#include "remote.h"
 
 /* Architecture-specific operations.  */
 
@@ -106,11 +107,11 @@ The search path for loading non-absolute
 
    GLOBAL FUNCTION
 
-   solib_open -- Find a shared library file and open it.
+   solib_bfd_open -- Find a shared library file and open BFD for it.
 
    SYNOPSIS
 
-   int solib_open (char *in_patname, char **found_pathname);
+   struct bfd *solib_open (char *in_pathname);
 
    DESCRIPTION
 
@@ -137,16 +138,17 @@ The search path for loading non-absolute
 
    RETURNS
 
-   file handle for opened solib, or -1 for failure.  */
+   BFD file handle for opened solib; throws error on failure.  */
 
-int
-solib_open (char *in_pathname, char **found_pathname)
+bfd *
+solib_bfd_open (char *in_pathname)
 {
   struct target_so_ops *ops = solib_ops (target_gdbarch);
   int found_file = -1;
   char *temp_pathname = NULL;
   char *p = in_pathname;
   int gdb_sysroot_is_empty;
+  bfd *abfd;
 
   gdb_sysroot_is_empty = (gdb_sysroot == NULL || *gdb_sysroot == 0);
 
@@ -168,6 +170,29 @@ solib_open (char *in_pathname, char **fo
       strcat (temp_pathname, in_pathname);
     }
 
+  /* Handle remote files.  */
+  if (remote_filename_p (temp_pathname))
+    {
+      temp_pathname = xstrdup (temp_pathname);
+      abfd = remote_bfd_open (temp_pathname, gnutarget);
+      if (!abfd)
+	{
+	  make_cleanup (xfree, temp_pathname);
+	  error (_("Could not open `%s' as an executable file: %s"),
+		 temp_pathname, bfd_errmsg (bfd_get_error ()));
+	}
+
+      if (!bfd_check_format (abfd, bfd_object))
+	{
+	  bfd_close (abfd);
+	  make_cleanup (xfree, temp_pathname);
+	  error (_("`%s': not in executable format: %s"),
+		 temp_pathname, bfd_errmsg (bfd_get_error ()));
+	}
+
+      return abfd;
+    }
+
   /* Now see if we can open it.  */
   found_file = open (temp_pathname, O_RDONLY | O_BINARY, 0);
 
@@ -228,16 +253,30 @@ solib_open (char *in_pathname, char **fo
 			OPF_TRY_CWD_FIRST, in_pathname, O_RDONLY | O_BINARY, 0,
 			&temp_pathname);
 
-  /* Done.  If not found, tough luck.  Return found_file and 
-     (optionally) found_pathname.  */
-  if (temp_pathname)
+  /* Done.  If still not found, error.  */
+  if (found_file < 0)
+    perror_with_name (in_pathname);
+
+  /* Leave temp_pathname allocated.  abfd->name will point to it.  */
+  abfd = bfd_fopen (temp_pathname, gnutarget, FOPEN_RB, found_file);
+  if (!abfd)
     {
-      if (found_pathname != NULL)
-	*found_pathname = temp_pathname;
-      else
-	xfree (temp_pathname);
+      close (found_file);
+      make_cleanup (xfree, temp_pathname);
+      error (_("Could not open `%s' as an executable file: %s"),
+	     temp_pathname, bfd_errmsg (bfd_get_error ()));
+    }
+
+  if (!bfd_check_format (abfd, bfd_object))
+    {
+      bfd_close (abfd);
+      make_cleanup (xfree, temp_pathname);
+      error (_("`%s': not in executable format: %s"),
+	     temp_pathname, bfd_errmsg (bfd_get_error ()));
     }
-  return found_file;
+
+  bfd_set_cacheable (abfd, 1);
+  return abfd;
 }
 
 
@@ -273,46 +312,24 @@ solib_map_sections (void *arg)
 {
   struct so_list *so = (struct so_list *) arg;	/* catch_errors bogon */
   char *filename;
-  char *scratch_pathname;
-  int scratch_chan;
   struct section_table *p;
   struct cleanup *old_chain;
   bfd *abfd;
 
   filename = tilde_expand (so->so_name);
-
   old_chain = make_cleanup (xfree, filename);
-  scratch_chan = solib_open (filename, &scratch_pathname);
-
-  if (scratch_chan < 0)
-    {
-      perror_with_name (filename);
-    }
-
-  /* Leave scratch_pathname allocated.  abfd->name will point to it.  */
-  abfd = bfd_fopen (scratch_pathname, gnutarget, FOPEN_RB, scratch_chan);
-  if (!abfd)
-    {
-      close (scratch_chan);
-      error (_("Could not open `%s' as an executable file: %s"),
-	     scratch_pathname, bfd_errmsg (bfd_get_error ()));
-    }
+  abfd = solib_bfd_open (filename);
+  do_cleanups (old_chain);
 
   /* Leave bfd open, core_xfer_memory and "info files" need it.  */
   so->abfd = abfd;
-  bfd_set_cacheable (abfd, 1);
 
   /* copy full path name into so_name, so that later symbol_file_add
      can find it */
-  if (strlen (scratch_pathname) >= SO_NAME_MAX_PATH_SIZE)
-    error (_("Full path name length of shared library exceeds SO_NAME_MAX_PATH_SIZE in so_list structure."));
-  strcpy (so->so_name, scratch_pathname);
+  if (strlen (bfd_get_filename (abfd)) >= SO_NAME_MAX_PATH_SIZE)
+    error (_("Shared library file name is too long."));
+  strcpy (so->so_name, bfd_get_filename (abfd));
 
-  if (!bfd_check_format (abfd, bfd_object))
-    {
-      error (_("\"%s\": not in executable format: %s."),
-	     scratch_pathname, bfd_errmsg (bfd_get_error ()));
-    }
   if (build_section_table (abfd, &so->sections, &so->sections_end))
     {
       error (_("Can't find the file sections in `%s': %s"),
@@ -339,9 +356,6 @@ solib_map_sections (void *arg)
 	}
     }
 
-  /* Free the file names, close the file now.  */
-  do_cleanups (old_chain);
-
   return (1);
 }
 
diff -urNp gdb-orig/gdb/solib-frv.c gdb-head/gdb/solib-frv.c
--- gdb-orig/gdb/solib-frv.c	2008-08-13 19:43:45.251186964 +0200
+++ gdb-head/gdb/solib-frv.c	2008-08-13 19:44:21.877527728 +0200
@@ -30,6 +30,7 @@
 #include "command.h"
 #include "gdbcmd.h"
 #include "elf/frv.h"
+#include "exceptions.h"
 
 /* Flag which indicates whether internal debug messages should be printed.  */
 static int solib_frv_debug;
@@ -645,12 +646,11 @@ enable_break2 (void)
       unsigned int interp_sect_size;
       gdb_byte *buf;
       bfd *tmp_bfd = NULL;
-      int tmp_fd = -1;
-      char *tmp_pathname = NULL;
       int status;
       CORE_ADDR addr, interp_loadmap_addr;
       gdb_byte addr_buf[FRV_PTR_SIZE];
       struct int_elf32_fdpic_loadmap *ldm;
+      volatile struct gdb_exception ex;
 
       /* Read the contents of the .interp section into a local buffer;
          the contents specify the dynamic linker this program uses.  */
@@ -668,25 +668,16 @@ enable_break2 (void)
          be trivial on GNU/Linux).  Therefore, we have to try an alternate
          mechanism to find the dynamic linker's base address.  */
 
-      tmp_fd  = solib_open (buf, &tmp_pathname);
-      if (tmp_fd >= 0)
-	tmp_bfd = bfd_fopen (tmp_pathname, gnutarget, FOPEN_RB, tmp_fd);
-
+      TRY_CATCH (ex, RETURN_MASK_ALL)
+        {
+          tmp_bfd = solib_bfd_open (buf);
+        }
       if (tmp_bfd == NULL)
 	{
 	  enable_break_failure_warning ();
 	  return 0;
 	}
 
-      /* Make sure the dynamic linker is really a useful object.  */
-      if (!bfd_check_format (tmp_bfd, bfd_object))
-	{
-	  warning (_("Unable to grok dynamic linker %s as an object file"), buf);
-	  enable_break_failure_warning ();
-	  bfd_close (tmp_bfd);
-	  return 0;
-	}
-
       status = frv_fdpic_loadmap_addresses (target_gdbarch,
                                             &interp_loadmap_addr, 0);
       if (status < 0)
diff -urNp gdb-orig/gdb/solib-svr4.c gdb-head/gdb/solib-svr4.c
--- gdb-orig/gdb/solib-svr4.c	2008-08-13 19:43:45.264185102 +0200
+++ gdb-head/gdb/solib-svr4.c	2008-08-13 19:44:21.885526583 +0200
@@ -42,6 +42,7 @@
 #include "elf-bfd.h"
 #include "exec.h"
 #include "auxv.h"
+#include "exceptions.h"
 
 static struct link_map_offsets *svr4_fetch_link_map_offsets (void);
 static int svr4_have_link_map_offsets (void);
@@ -1038,8 +1039,7 @@ enable_break (void)
       struct so_list *so;
       bfd *tmp_bfd = NULL;
       struct target_ops *tmp_bfd_target;
-      int tmp_fd = -1;
-      char *tmp_pathname = NULL;
+      volatile struct gdb_exception ex;
 
       /* Read the contents of the .interp section into a local buffer;
          the contents specify the dynamic linker this program uses.  */
@@ -1058,21 +1058,13 @@ enable_break (void)
          be trivial on GNU/Linux).  Therefore, we have to try an alternate
          mechanism to find the dynamic linker's base address.  */
 
-      tmp_fd = solib_open (buf, &tmp_pathname);
-      if (tmp_fd >= 0)
-	tmp_bfd = bfd_fopen (tmp_pathname, gnutarget, FOPEN_RB, tmp_fd);
-
+      TRY_CATCH (ex, RETURN_MASK_ALL)
+        {
+	  tmp_bfd = solib_bfd_open (buf);
+	}
       if (tmp_bfd == NULL)
 	goto bkpt_at_symbol;
 
-      /* Make sure the dynamic linker's really a useful object.  */
-      if (!bfd_check_format (tmp_bfd, bfd_object))
-	{
-	  warning (_("Unable to grok dynamic linker %s as an object file"), buf);
-	  bfd_close (tmp_bfd);
-	  goto bkpt_at_symbol;
-	}
-
       /* Now convert the TMP_BFD into a target.  That way target, as
          well as BFD operations can be used.  Note that closing the
          target will also close the underlying bfd.  */
@@ -1166,7 +1158,6 @@ enable_break (void)
       /* For whatever reason we couldn't set a breakpoint in the dynamic
          linker.  Warn and drop into the old code.  */
     bkpt_at_symbol:
-      xfree (tmp_pathname);
       warning (_("Unable to find dynamic linker breakpoint function.\n"
                "GDB will be unable to debug shared library initializers\n"
                "and track explicitly loaded dynamic code."));
diff -urNp gdb-orig/gdb/solist.h gdb-head/gdb/solist.h
--- gdb-orig/gdb/solist.h	2008-05-19 17:48:16.000000000 +0200
+++ gdb-head/gdb/solist.h	2008-08-13 19:44:21.889526010 +0200
@@ -127,7 +127,7 @@ void free_so (struct so_list *so);
 struct so_list *master_so_list (void);
 
 /* Find solib binary file and open it.  */
-extern int solib_open (char *in_pathname, char **found_pathname);
+extern bfd *solib_bfd_open (char *in_pathname);
 
 /* FIXME: gdbarch needs to control this variable */
 extern struct target_so_ops *current_target_so_ops;
diff -urNp gdb-orig/gdb/symfile.c gdb-head/gdb/symfile.c
--- gdb-orig/gdb/symfile.c	2008-08-08 16:42:41.000000000 +0200
+++ gdb-head/gdb/symfile.c	2008-08-13 20:30:46.973608091 +0200
@@ -53,6 +53,7 @@
 #include "varobj.h"
 #include "elf-bfd.h"
 #include "solib.h"
+#include "remote.h"
 
 #include <sys/types.h>
 #include <fcntl.h>
@@ -1266,7 +1267,10 @@ build_id_verify (const char *filename, s
   int retval = 0;
 
   /* We expect to be silent on the non-existing files.  */
-  abfd = bfd_openr (filename, gnutarget);
+  if (remote_filename_p (filename))
+    abfd = remote_bfd_open (filename, gnutarget);
+  else
+    abfd = bfd_openr (filename, gnutarget);
   if (abfd == NULL)
     return 0;
 
@@ -1357,18 +1361,22 @@ static int
 separate_debug_file_exists (const char *name, unsigned long crc)
 {
   unsigned long file_crc = 0;
-  int fd;
+  bfd *abfd;
   gdb_byte buffer[8*1024];
   int count;
 
-  fd = open (name, O_RDONLY | O_BINARY);
-  if (fd < 0)
+  if (remote_filename_p (name))
+    abfd = remote_bfd_open (name, gnutarget);
+  else
+    abfd = bfd_openr (name, gnutarget);
+
+  if (!abfd)
     return 0;
 
-  while ((count = read (fd, buffer, sizeof (buffer))) > 0)
+  while ((count = bfd_bread (buffer, sizeof (buffer), abfd)) > 0)
     file_crc = gnu_debuglink_crc32 (file_crc, buffer, count);
 
-  close (fd);
+  bfd_close (abfd);
 
   return crc == file_crc;
 }
@@ -1614,6 +1622,28 @@ symfile_bfd_open (char *name)
   int desc;
   char *absolute_name;
 
+  if (remote_filename_p (name))
+    {
+      name = xstrdup (name);
+      sym_bfd = remote_bfd_open (name, gnutarget);
+      if (!sym_bfd)
+	{
+	  make_cleanup (xfree, name);
+	  error (_("`%s': can't open to read symbols: %s."), name,
+		 bfd_errmsg (bfd_get_error ()));
+	}
+
+      if (!bfd_check_format (sym_bfd, bfd_object))
+	{
+	  bfd_close (sym_bfd);
+	  make_cleanup (xfree, name);
+	  error (_("`%s': can't read symbols: %s."), name,
+		 bfd_errmsg (bfd_get_error ()));
+	}
+
+      return sym_bfd;
+    }
+
   name = tilde_expand (name);	/* Returns 1st new malloc'd copy.  */
 
   /* Look down path for it, allocate 2nd new malloc'd copy.  */
@@ -1644,7 +1674,7 @@ symfile_bfd_open (char *name)
     {
       close (desc);
       make_cleanup (xfree, name);
-      error (_("\"%s\": can't open to read symbols: %s."), name,
+      error (_("`%s': can't open to read symbols: %s."), name,
 	     bfd_errmsg (bfd_get_error ()));
     }
   bfd_set_cacheable (sym_bfd, 1);
@@ -1656,7 +1686,7 @@ symfile_bfd_open (char *name)
          with the bfd).  */
       bfd_close (sym_bfd);	/* This also closes desc.  */
       make_cleanup (xfree, name);
-      error (_("\"%s\": can't read symbols: %s."), name,
+      error (_("`%s': can't read symbols: %s."), name,
 	     bfd_errmsg (bfd_get_error ()));
     }
 
@@ -2357,7 +2387,10 @@ reread_symbols (void)
 	      if (!bfd_close (objfile->obfd))
 		error (_("Can't close BFD for %s: %s"), objfile->name,
 		       bfd_errmsg (bfd_get_error ()));
-	      objfile->obfd = bfd_openr (obfd_filename, gnutarget);
+	      if (remote_filename_p (obfd_filename))
+		objfile->obfd = remote_bfd_open (obfd_filename, gnutarget);
+	      else
+		objfile->obfd = bfd_openr (obfd_filename, gnutarget);
 	      if (objfile->obfd == NULL)
 		error (_("Can't open %s to read symbols."), objfile->name);
 	      /* bfd_openr sets cacheable to true, which is what we want.  */
-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com