Move vgdb special case into remote_filesystem_is_local

Valgrind GDB (vgdb) presents itself as a remote target but works on
the local filesystem.  gdb_bfd_open contained a special case to make
vgdb work with "target:" sysroots, but the implementation meant that
GDB would fall back to the local filesystem if *any* to_fileio_open
method failed with ENOSYS for *any* reason.  This commit moves the
vgdb special case to remote_filesystem_is_local to allow the fallback
to be restricted only to the specific case that remote file transfer
is unsupported.  This commit also adds a warning which is displayed
the first time the fallback is used.

gdb/ChangeLog:

	* gdb_bfd.c (gdb_bfd_open): Move vgdb special case to...
	* remote.c (remote_filesystem_is_local): ...here.

1 files changed, 1 insertions, 15 deletions

diff --git a/gdb/gdb_bfd.c b/gdb/gdb_bfd.c
index 3d5d23f7cb8..2cd91ef96b1 100644
--- a/gdb/gdb_bfd.c
+++ b/gdb/gdb_bfd.c
@@ -326,25 +326,11 @@ gdb_bfd_open (const char *name, const char *target, int fd)
 	{
 	  gdb_assert (fd == -1);
 
-	  abfd = gdb_bfd_openr_iovec (name, target,
+	  return gdb_bfd_openr_iovec (name, target,
 				      gdb_bfd_iovec_fileio_open, NULL,
 				      gdb_bfd_iovec_fileio_pread,
 				      gdb_bfd_iovec_fileio_close,
 				      gdb_bfd_iovec_fileio_fstat);
-
-	  if (abfd != NULL || errno != ENOSYS)
-	    return abfd;
-
-	  /* gdb_bfd_iovec_fileio_open failed with ENOSYS.  This can
-	     happen, for example, with vgdb (Valgrind GDB), which
-	     presents itself as a remote target but works on the local
-	     filesystem: it does not implement remote get and users
-	     are not expected to set gdb_sysroot.  To handle this case
-	     we fall back to trying the local filesystem iff
-	     gdb_sysroot is exactly TARGET_SYSROOT_PREFIX.  */
-	  if (gdb_sysroot == NULL
-	      || strcmp (gdb_sysroot, TARGET_SYSROOT_PREFIX) != 0)
-	    return NULL;
 	}
 
       name += strlen (TARGET_SYSROOT_PREFIX);