Warn when accessing binaries from remote targets

GDB provides no indicator of progress during file operations, and can
appear to have locked up during slow remote transfers.  This commit
updates GDB to print a warning each time a file is accessed over RSP.
An additional message detailing how to avoid remote transfers is
printed for the first transfer only.

gdb/ChangeLog:

	* target.h (struct target_ops) <to_fileio_open>: New argument
	warn_if_slow.  Update comment.  All implementations updated.
	(target_fileio_open_warn_if_slow): New declaration.
	* target.c (target_fileio_open): Renamed as...
	(target_fileio_open_1): ...this.  New argument warn_if_slow.
	Pass warn_if_slow to implementation.  Update debug printing.
	(target_fileio_open): New function.
	(target_fileio_open_warn_if_slow): Likewise.
	* gdb_bfd.c (gdb_bfd_iovec_fileio_open): Use new function
	target_fileio_open_warn_if_slow.

gdb/testsuite/ChangeLog:

	* gdb.trace/pending.exp: Cope with remote transfer warnings.

1 files changed, 31 insertions, 7 deletions

diff --git a/gdb/target.c b/gdb/target.c
index e41a33858b..a0a55d909d 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -2779,11 +2779,13 @@ release_fileio_fd (int fd, fileio_fh_t *fh)
 #define fileio_fd_to_fh(fd) \
   VEC_index (fileio_fh_t, fileio_fhandles, (fd))
 
-/* See target.h.  */
+/* Helper for target_fileio_open and
+   target_fileio_open_warn_if_slow.  */
 
-int
-target_fileio_open (struct inferior *inf, const char *filename,
-		    int flags, int mode, int *target_errno)
+static int
+target_fileio_open_1 (struct inferior *inf, const char *filename,
+		      int flags, int mode, int warn_if_slow,
+		      int *target_errno)
 {
   struct target_ops *t;
 
@@ -2792,7 +2794,7 @@ target_fileio_open (struct inferior *inf, const char *filename,
       if (t->to_fileio_open != NULL)
 	{
 	  int fd = t->to_fileio_open (t, inf, filename, flags, mode,
-				      target_errno);
+				      warn_if_slow, target_errno);
 
 	  if (fd < 0)
 	    fd = -1;
@@ -2801,11 +2803,12 @@ target_fileio_open (struct inferior *inf, const char *filename,
 
 	  if (targetdebug)
 	    fprintf_unfiltered (gdb_stdlog,
-				"target_fileio_open (%d,%s,0x%x,0%o)"
+				"target_fileio_open (%d,%s,0x%x,0%o,%d)"
 				" = %d (%d)\n",
 				inf == NULL ? 0 : inf->num,
 				filename, flags, mode,
-				fd, fd != -1 ? 0 : *target_errno);
+				warn_if_slow, fd,
+				fd != -1 ? 0 : *target_errno);
 	  return fd;
 	}
     }
@@ -2817,6 +2820,27 @@ target_fileio_open (struct inferior *inf, const char *filename,
 /* See target.h.  */
 
 int
+target_fileio_open (struct inferior *inf, const char *filename,
+		    int flags, int mode, int *target_errno)
+{
+  return target_fileio_open_1 (inf, filename, flags, mode, 0,
+			       target_errno);
+}
+
+/* See target.h.  */
+
+int
+target_fileio_open_warn_if_slow (struct inferior *inf,
+				 const char *filename,
+				 int flags, int mode, int *target_errno)
+{
+  return target_fileio_open_1 (inf, filename, flags, mode, 1,
+			       target_errno);
+}
+
+/* See target.h.  */
+
+int
 target_fileio_pwrite (int fd, const gdb_byte *write_buf, int len,
 		      ULONGEST offset, int *target_errno)
 {