diff mbox

[v2] Warn when accessing binaries from remote targets

Message ID 1439472239-15866-1-git-send-email-gbenson@redhat.com
State New
Headers show

Commit Message

Gary Benson Aug. 13, 2015, 1:23 p.m. UTC
Hi all,

This is an updated version of the patch I previously mailed to add
a warning message when GDB initiates transfers from remote targets.
This version adds a new function, target_fileio_open_warn_if_slow,
as suggested by Andrew and Doug, and moves the message printing
code into remote_hostio_open.

Is this ok to commit?  To HEAD?  To the branch?  To both?

Cheers,
Gary

---
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.
---
 gdb/ChangeLog                       |   13 ++++++++++++
 gdb/gdb_bfd.c                       |    9 ++++---
 gdb/inf-child.c                     |    3 +-
 gdb/linux-nat.c                     |    3 +-
 gdb/remote.c                        |   26 ++++++++++++++++++++---
 gdb/target.c                        |   38 ++++++++++++++++++++++++++++------
 gdb/target.h                        |   17 ++++++++++++--
 gdb/testsuite/ChangeLog             |    4 +++
 gdb/testsuite/gdb.trace/pending.exp |    8 +++---
 9 files changed, 97 insertions(+), 24 deletions(-)

Comments

Andrew Burgess Aug. 13, 2015, 3:07 p.m. UTC | #1
* Gary Benson <gbenson@redhat.com> [2015-08-13 14:23:59 +0100]:

> This version adds a new function, target_fileio_open_warn_if_slow,
> as suggested by Andrew and Doug, and moves the message printing
> code into remote_hostio_open.

I'm not a maintainer, but this revision addresses my earlier concerns.

Thanks,
Andrew
Pedro Alves Aug. 21, 2015, 3:41 p.m. UTC | #2
On 08/13/2015 02:23 PM, Gary Benson wrote:

> +  if (warn_if_slow)
> +    {
> +      static int warning_issued = 0;
> +
> +      printf_unfiltered (_("Reading %s from remote target...\n"),
> +			 filename);
> +
> +      if (!warning_issued)
> +	{
> +	  warning (_("File transfers from remote targets can be slow."
> +		     " Use \"set sysroot\" with no arguments to access"
> +		     " files locally instead."));

I wonder whether "with no arguments" is necessary here.  I'd suggest dropping
that bit.  It think it may even be confusing, as what the user should do is
point at a local copy of the target filesystem, using "set sysroot /path/to/copy".
The host's filesystem is not necessarily the correct one, and often isn't.

Otherwise this looks good to me.

Thanks,
Pedro Alves
Gary Benson Aug. 21, 2015, 4:23 p.m. UTC | #3
Pedro Alves wrote:
> On 08/13/2015 02:23 PM, Gary Benson wrote:
> > +  if (warn_if_slow)
> > +    {
> > +      static int warning_issued = 0;
> > +
> > +      printf_unfiltered (_("Reading %s from remote target...\n"),
> > +			 filename);
> > +
> > +      if (!warning_issued)
> > +	{
> > +	  warning (_("File transfers from remote targets can be slow."
> > +		     " Use \"set sysroot\" with no arguments to access"
> > +		     " files locally instead."));
> 
> I wonder whether "with no arguments" is necessary here.  I'd suggest
> dropping that bit.  It think it may even be confusing, as what the
> user should do is point at a local copy of the target filesystem,
> using "set sysroot /path/to/copy".  The host's filesystem is not
> necessarily the correct one, and often isn't.
> 
> Otherwise this looks good to me.

Pushed to master and 7.10 with that change.

Thanks,
Gary
diff mbox

Patch

diff --git a/gdb/gdb_bfd.c b/gdb/gdb_bfd.c
index 1781d80..264b611 100644
--- a/gdb/gdb_bfd.c
+++ b/gdb/gdb_bfd.c
@@ -222,10 +222,11 @@  gdb_bfd_iovec_fileio_open (struct bfd *abfd, void *inferior)
 
   gdb_assert (is_target_filename (filename));
 
-  fd = target_fileio_open ((struct inferior *) inferior,
-			   filename + strlen (TARGET_SYSROOT_PREFIX),
-			   FILEIO_O_RDONLY, 0,
-			   &target_errno);
+  fd = target_fileio_open_warn_if_slow ((struct inferior *) inferior,
+					filename
+					+ strlen (TARGET_SYSROOT_PREFIX),
+					FILEIO_O_RDONLY, 0,
+					&target_errno);
   if (fd == -1)
     {
       errno = fileio_errno_to_host (target_errno);
diff --git a/gdb/inf-child.c b/gdb/inf-child.c
index 0326a93..ada570d 100644
--- a/gdb/inf-child.c
+++ b/gdb/inf-child.c
@@ -209,7 +209,8 @@  inf_child_pid_to_exec_file (struct target_ops *self, int pid)
 static int
 inf_child_fileio_open (struct target_ops *self,
 		       struct inferior *inf, const char *filename,
-		       int flags, int mode, int *target_errno)
+		       int flags, int mode, int warn_if_slow,
+		       int *target_errno)
 {
   int nat_flags;
   mode_t nat_mode;
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index be7a915..f21b1c5 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -4920,7 +4920,8 @@  linux_nat_fileio_pid_of (struct inferior *inf)
 static int
 linux_nat_fileio_open (struct target_ops *self,
 		       struct inferior *inf, const char *filename,
-		       int flags, int mode, int *target_errno)
+		       int flags, int mode, int warn_if_slow,
+		       int *target_errno)
 {
   int nat_flags;
   mode_t nat_mode;
diff --git a/gdb/remote.c b/gdb/remote.c
index ca1f0df..d9a8bb7 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -10359,12 +10359,29 @@  remote_hostio_set_filesystem (struct inferior *inf, int *remote_errno)
 static int
 remote_hostio_open (struct target_ops *self,
 		    struct inferior *inf, const char *filename,
-		    int flags, int mode, int *remote_errno)
+		    int flags, int mode, int warn_if_slow,
+		    int *remote_errno)
 {
   struct remote_state *rs = get_remote_state ();
   char *p = rs->buf;
   int left = get_remote_packet_size () - 1;
 
+  if (warn_if_slow)
+    {
+      static int warning_issued = 0;
+
+      printf_unfiltered (_("Reading %s from remote target...\n"),
+			 filename);
+
+      if (!warning_issued)
+	{
+	  warning (_("File transfers from remote targets can be slow."
+		     " Use \"set sysroot\" with no arguments to access"
+		     " files locally instead."));
+	  warning_issued = 1;
+	}
+    }
+
   if (remote_hostio_set_filesystem (inf, remote_errno) != 0)
     return -1;
 
@@ -10613,7 +10630,7 @@  remote_filesystem_is_local (struct target_ops *self)
 	     filename is irrelevant, we only care about whether
 	     the stub recognizes the packet or not.  */
 	  fd = remote_hostio_open (self, NULL, "just probing",
-				   FILEIO_O_RDONLY, 0700,
+				   FILEIO_O_RDONLY, 0700, 0,
 				   &remote_errno);
 
 	  if (fd >= 0)
@@ -10735,7 +10752,7 @@  remote_file_put (const char *local_file, const char *remote_file, int from_tty)
   fd = remote_hostio_open (find_target_at (process_stratum), NULL,
 			   remote_file, (FILEIO_O_WRONLY | FILEIO_O_CREAT
 					 | FILEIO_O_TRUNC),
-			   0700, &remote_errno);
+			   0700, 0, &remote_errno);
   if (fd == -1)
     remote_hostio_error (remote_errno);
 
@@ -10819,7 +10836,8 @@  remote_file_get (const char *remote_file, const char *local_file, int from_tty)
     error (_("command can only be used with remote target"));
 
   fd = remote_hostio_open (find_target_at (process_stratum), NULL,
-			   remote_file, FILEIO_O_RDONLY, 0, &remote_errno);
+			   remote_file, FILEIO_O_RDONLY, 0, 0,
+			   &remote_errno);
   if (fd == -1)
     remote_hostio_error (remote_errno);
 
diff --git a/gdb/target.c b/gdb/target.c
index e41a338..a0a55d9 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)
 {
diff --git a/gdb/target.h b/gdb/target.h
index e283c86..1fdaf00 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -873,11 +873,14 @@  struct target_ops
     /* Open FILENAME on the target, in the filesystem as seen by INF,
        using FLAGS and MODE.  If INF is NULL, use the filesystem seen
        by the debugger (GDB or, for remote targets, the remote stub).
-       Return a target file descriptor, or -1 if an error occurs (and
-       set *TARGET_ERRNO).  */
+       If WARN_IF_SLOW is nonzero, print a warning message if the file
+       is being accessed over a link that may be slow.  Return a
+       target file descriptor, or -1 if an error occurs (and set
+       *TARGET_ERRNO).  */
     int (*to_fileio_open) (struct target_ops *,
 			   struct inferior *inf, const char *filename,
-			   int flags, int mode, int *target_errno);
+			   int flags, int mode, int warn_if_slow,
+			   int *target_errno);
 
     /* Write up to LEN bytes from WRITE_BUF to FD on the target.
        Return the number of bytes written, or -1 if an error occurs
@@ -2007,6 +2010,14 @@  extern int target_fileio_open (struct inferior *inf,
 			       const char *filename, int flags,
 			       int mode, int *target_errno);
 
+/* Like target_fileio_open, but print a warning message if the
+   file is being accessed over a link that may be slow.  */
+extern int target_fileio_open_warn_if_slow (struct inferior *inf,
+					    const char *filename,
+					    int flags,
+					    int mode,
+					    int *target_errno);
+
 /* Write up to LEN bytes from WRITE_BUF to FD on the target.
    Return the number of bytes written, or -1 if an error occurs
    (and set *TARGET_ERRNO).  */
diff --git a/gdb/testsuite/gdb.trace/pending.exp b/gdb/testsuite/gdb.trace/pending.exp
index 0399807..9938c5a 100644
--- a/gdb/testsuite/gdb.trace/pending.exp
+++ b/gdb/testsuite/gdb.trace/pending.exp
@@ -221,7 +221,7 @@  proc pending_tracepoint_resolved_during_trace { trace_type } \
 		fail $test
 	    }
 	}
-	-re "Continuing.\r\n\r\nBreakpoint.*marker.*at.*$srcfile.*$gdb_prompt $" {
+	-re "Continuing.\r\n(Reading .* from remote target...\r\n)?\r\nBreakpoint.*marker.*at.*$srcfile.*$gdb_prompt $" {
 	    pass $test
 	}
     }
@@ -294,7 +294,7 @@  proc pending_tracepoint_installed_during_trace { trace_type } \
 		fail $test
 	    }
 	}
-	-re "Continuing.\r\n\r\nBreakpoint.*marker.*at.*$srcfile.*$gdb_prompt $" {
+	-re "Continuing.\r\n(Reading .* from remote target...\r\n)?\r\nBreakpoint.*marker.*at.*$srcfile.*$gdb_prompt $" {
            pass $test
        }
     }
@@ -391,7 +391,7 @@  proc pending_tracepoint_disconnect_after_resolved { trace_type } \
 
     gdb_test "continue" "Continuing.\r\n\r\nBreakpoint.*marker.*at.*pending.c.*" \
 	"continue to marker 1"
-    gdb_test "continue" "Continuing.\r\n\r\nBreakpoint.*marker.*at.*pending.c.*" \
+    gdb_test "continue" "Continuing.\r\n(Reading .* from remote target...\r\n)?\r\nBreakpoint.*marker.*at.*pending.c.*" \
 	"continue to marker 2"
 
     # There should be no pending tracepoint, so no warning should be emitted.
@@ -473,7 +473,7 @@  proc pending_tracepoint_with_action_resolved { trace_type } \
 		fail $test
             }
 	}
-	-re "Continuing.\r\n\r\nBreakpoint.*marker.*at.*$srcfile.*$gdb_prompt $" {
+	-re "Continuing.\r\n(Reading .* from remote target...\r\n)?\r\nBreakpoint.*marker.*at.*$srcfile.*$gdb_prompt $" {
 	    pass "continue to marker 2"
 	}