[PATCH 2/3 v2] Implement vFile:fstat: packet in gdbserver

[Gary Benson <gbenson at redhat dot com>]

Eli, could you please review the qSupported part of the docs in
this patch?  The remainder of the patch is unchanged from the
patch you previously approved.

Thanks,
Gary

---
This patch adds a new packet "vFile:fstat:" to gdbserver.
This can be used by clients to retrieve information about
open files.

gdb/ChangeLog:

	* NEWS: Announce new vFile:fstat packet.

gdb/doc/ChangeLog:

	* gdb.texinfo (Host I/O Packets): Document the vFile:fstat
	packet.
	(General Query Packets): Document the vFile:fstat qSupported
	features.

gdb/gdbserver/ChangeLog:

	* hostio.c (sys/types.h): New include.
	(sys/stat.h): Likewise.
	(common-remote-fileio.h): Likewise.
	(handle_fstat): New function.
	(handle_vFile): Handle vFile:fstat packets.
	* server.c (handle_query): Report vFile:fstat as supported.
---
 gdb/ChangeLog           |    4 ++++
 gdb/NEWS                |    3 +++
 gdb/doc/ChangeLog       |    7 +++++++
 gdb/doc/gdb.texinfo     |   15 +++++++++++++++
 gdb/gdbserver/ChangeLog |    9 +++++++++
 gdb/gdbserver/hostio.c  |   41 +++++++++++++++++++++++++++++++++++++++++
 gdb/gdbserver/server.c  |    2 ++
 7 files changed, 81 insertions(+), 0 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index 49dc0e6..f08f972 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -73,6 +73,9 @@ hwbreak stop reason
   Indicates the target stopped for a hardware breakpoint.  This is
   required for correct non-stop mode operation.
 
+vFile:fstat:
+  Return information about files on the remote system.
+
 * The info record command now shows the recording format and the
   branch tracing configuration for the current thread when using
   the btrace record target.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 1ee1346..b197c1f 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -36062,6 +36062,11 @@ These are the currently defined stub features and their properties:
 @tab @samp{-}
 @tab No
 
+@item @samp{vFile:fstat}
+@tab No
+@tab @samp{-}
+@tab Yes
+
 @end multitable
 
 These are the currently defined stub features, in more detail:
@@ -36250,6 +36255,9 @@ breakpoints.
 The remote stub reports the @samp{hwbreak} stop reason for hardware
 breakpoints.
 
+@item vFile:fstat
+The remote stub understands the @samp{vFile:fstat} packet.
+
 @end table
 
 @item qSymbol::
@@ -37411,6 +37419,13 @@ packet is used.  @samp{vFile:write} returns the number of bytes written,
 which may be shorter than the length of @var{data}, or -1 if an
 error occurred.
 
+@item vFile:fstat: @var{fd}
+Get information about the open file corresponding to @var{fd}.
+On success the information is returned as a binary attachment
+and the return value is the size of this attachment in bytes.
+If an error occurs the return value is -1.  The format of the
+returned binary attachment is as described in @ref{struct stat}.
+
 @item vFile:unlink: @var{filename}
 Delete the file at @var{filename} on the target.  Return 0,
 or -1 if an error occurs.  The @var{filename} is a string.
diff --git a/gdb/gdbserver/hostio.c b/gdb/gdbserver/hostio.c
index ec29eb9..cc0192b 100644
--- a/gdb/gdbserver/hostio.c
+++ b/gdb/gdbserver/hostio.c
@@ -25,6 +25,9 @@
 #include <fcntl.h>
 #include <limits.h>
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include "common-remote-fileio.h"
 
 extern int remote_debug;
 
@@ -412,6 +415,42 @@ handle_pwrite (char *own_buf, int packet_len)
 }
 
 static void
+handle_fstat (char *own_buf, int *new_packet_len)
+{
+  int fd, bytes_sent;
+  char *p;
+  struct stat st;
+  struct fio_stat fst;
+
+  p = own_buf + strlen ("vFile:fstat:");
+
+  if (require_int (&p, &fd)
+      || require_valid_fd (fd)
+      || require_end (p))
+    {
+      hostio_packet_error (own_buf);
+      return;
+    }
+
+  if (fstat (fd, &st) == -1)
+    {
+      hostio_error (own_buf);
+      return;
+    }
+
+  remote_fileio_to_fio_stat (&st, &fst);
+
+  bytes_sent = hostio_reply_with_data (own_buf,
+				       (char *) &fst, sizeof (fst),
+				       new_packet_len);
+
+  /* If the response does not fit into a single packet, do not attempt
+     to return a partial response, but simply fail.  */
+  if (bytes_sent < sizeof (fst))
+    sprintf (own_buf, "F-1,%x", FILEIO_ENOSYS);
+}
+
+static void
 handle_close (char *own_buf)
 {
   int fd, ret;
@@ -517,6 +556,8 @@ handle_vFile (char *own_buf, int packet_len, int *new_packet_len)
     handle_pread (own_buf, new_packet_len);
   else if (startswith (own_buf, "vFile:pwrite:"))
     handle_pwrite (own_buf, packet_len);
+  else if (startswith (own_buf, "vFile:fstat:"))
+    handle_fstat (own_buf, new_packet_len);
   else if (startswith (own_buf, "vFile:close:"))
     handle_close (own_buf);
   else if (startswith (own_buf, "vFile:unlink:"))
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 4189877..4d8faa3 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -2082,6 +2082,8 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
       if (target_supports_stopped_by_hw_breakpoint ())
 	strcat (own_buf, ";hwbreak+");
 
+      strcat (own_buf, ";vFile:fstat+");
+
       return;
     }
 
-- 
1.7.1