Implement remote_pid_to_exec_file using qXfer:exec-file:read

This commit adds a new packet "qXfer:exec-file:read" to the remote
protocol that can be used to obtain the pathname of the file that
was executed to create a process on the remote system.  Support for
this packet is added to GDB and remote_ops.to_pid_to_exec_file is
implemented using it.

gdb/ChangeLog:

	* target.h (TARGET_OBJECT_EXEC_FILE): New enum value.
	* remote.c (PACKET_qXfer_exec_file): Likewise.
	(remote_protocol_features): Register the
	"qXfer:exec-file:read" feature.
	(remote_xfer_partial): Handle TARGET_OBJECT_EXEC_FILE.
	(remote_pid_to_exec_file): New function.
	(init_remote_ops): Initialize to_pid_to_exec_file.
	(_initialize_remote): Register new "set/show remote
	pid-to-exec-file-packet" command.
	* NEWS: Announce new qXfer:exec-file:read packet.

gdb/doc/ChangeLog:

	* gdb.texinfo (Remote Configuration): Document the "set/show
	remote pid-to-exec-file-packet" command.
	(General Query Packets): Document the qXfer:exec-file:read
	qSupported features.  Document the qXfer:exec-file:read packet.

2 files changed, 30 insertions, 0 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index f10bdf5..1bb7f41 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,5 +1,12 @@
 2015-04-17  Gary Benson <gbenson@redhat.com>
 
+	* gdb.texinfo (Remote Configuration): Document the "set/show
+	remote pid-to-exec-file-packet" command.
+	(General Query Packets): Document the qXfer:exec-file:read
+	qSupported features.  Document the qXfer:exec-file:read packet.
+
+2015-04-17  Gary Benson <gbenson@redhat.com>
+
 	* gdb.texinfo (set sysroot): Document that "set sysroot" also
 	applies to executable paths if supplied to GDB as absolute.
 
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 7f765d0..964f9c4 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -19791,6 +19791,10 @@ are:
 @tab @code{Z4}
 @tab @code{awatch}
 
+@item @code{pid-to-exec-file}
+@tab @code{qXfer:exec-file:read}
+@tab @code{attach}, @code{run}
+
 @item @code{target-features}
 @tab @code{qXfer:features:read}
 @tab @code{set architecture}
@@ -36016,6 +36020,11 @@ These are the currently defined stub features and their properties:
 @tab @samp{-}
 @tab Yes
 
+@item @samp{qXfer:exec-file:read}
+@tab No
+@tab @samp{-}
+@tab Yes
+
 @item @samp{qXfer:features:read}
 @tab No
 @tab @samp{-}
@@ -36219,6 +36228,10 @@ packet (@pxref{qXfer btrace read}).
 The remote stub understands the @samp{qXfer:btrace-conf:read}
 packet (@pxref{qXfer btrace-conf read}).
 
+@item qXfer:exec-file:read
+The remote stub understands the @samp{qXfer:exec-file:read} packet
+(@pxref{qXfer executable filename read}).
+
 @item qXfer:features:read
 The remote stub understands the @samp{qXfer:features:read} packet
 (@pxref{qXfer target description read}).
@@ -36533,6 +36546,16 @@ Return a description of the current branch trace configuration.
 This packet is not probed by default; the remote stub must request it
 by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
 
+@item qXfer:exec-file:read:@var{annex}:@var{offset},@var{length}
+@anchor{qXfer executable filename read}
+Return the full absolute name of the file that was executed to create
+a process running on the remote system.  The annex specifies the
+numeric process ID of the process to query, encoded as a hexadecimal
+number.
+
+This packet is not probed by default; the remote stub must request it,
+by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
+
 @item qXfer:features:read:@var{annex}:@var{offset},@var{length}
 @anchor{qXfer target description read}
 Access the @dfn{target description}.  @xref{Target Descriptions}.  The