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Extend "set cwd" to work on gdbserver

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This is the "natural" extension necessary for the "set cwd" command
(and the whole "set the inferior's cwd" logic) to work on gdbserver.

The idea here is to have a new remote packet, QSetWorkingDir (name
adopted from LLDB's extension to the RSP, as can be seen at
<https://raw.githubusercontent.com/llvm-mirror/lldb/master/docs/lldb-gdb-remote.txt>),
which sends an hex-encoded string representing the working directory
that the remote inferior will use.  There is a slight difference from
the packet proposed by LLDB: GDB's version will accept empty
arguments, meaning that the user wants to clear the previously set
working directory for the inferior (i.e., "set cwd" without arguments
on GDB).

For UNIX-like targets this feature is already implemented on
nat/fork-inferior.c, and all gdbserver has to do is to basically
implement "set_inferior_cwd" and call it whenever such packet arrives.
For other targets, like Windows, it is possible to use the existing
"get_inferior_cwd" function and do the necessary steps to make sure
that the inferior will use the specified working directory.

Aside from that, the patch consists basically of updates to the
testcase (making it available on remote targets) and the
documentation.

No regressions found.

gdb/ChangeLog:
2017-10-04  Sergio Durigan Junior  <sergiodj@redhat.com>

	* NEWS (Changes since GDB 8.0): Add entry about new
	'set-cwd-on-gdbserver' feature.
	(New remote packets): Add entry for QSetWorkingDir.
	* common/common-inferior.h (set_inferior_cwd): New prototype.
	* infcmd.c (set_inferior_cwd): Remove "static".
	(show_cwd_command): Expand text to include remote debugging.
	* remote.c: Add PACKET_QSetWorkingDir.
	(remote_protocol_features) <QSetWorkingDir>: New entry for
	PACKET_QSetWorkingDir.
	(extended_remote_set_inferior_cwd): New function.
	(extended_remote_create_inferior): Call
	"extended_remote_set_inferior_cwd".
	(_initialize_remote): Call "add_packet_config_cmd" for
	QSetWorkingDir.

gdb/gdbserver/ChangeLog:
2017-10-04  Sergio Durigan Junior  <sergiodj@redhat.com>

	* inferiors.c (set_inferior_cwd): New function.
	* server.c (handle_general_set): Handle QSetWorkingDir packet.
	(handle_query): Inform that QSetWorkingDir is supported.
	* win32-low.c (create_process): Pass the inferior's cwd to
	CreateProcess.

gdb/testsuite/ChangeLog:
2017-10-04  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.base/set-cwd.exp: Make it available on
	native-extended-gdbserver.

gdb/doc/ChangeLog:
2017-10-04  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.texinfo (Starting your Program) <The working directory.>:
	Mention remote debugging.
	(Working Directory) <Your Program's Working Directory>:
	Likewise.
	(Connecting) <Remote Packet>: Add "set-working-dir"
	and "QSetWorkingDir" to the table.
	(Remote Protocol) <QSetWorkingDir>: New item, explaining the
	packet.
This commit is contained in:
Sergio Durigan Junior 2017-09-20 19:15:40 -04:00
parent d092c5a246
commit bc3b087de2
13 changed files with 203 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
gdb/ChangeLog
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@ -1,3 +1,20 @@
2017-10-04 Sergio Durigan Junior <sergiodj@redhat.com>
* NEWS (Changes since GDB 8.0): Add entry about new
'set-cwd-on-gdbserver' feature.
(New remote packets): Add entry for QSetWorkingDir.
* common/common-inferior.h (set_inferior_cwd): New prototype.
* infcmd.c (set_inferior_cwd): Remove "static".
(show_cwd_command): Expand text to include remote debugging.
* remote.c: Add PACKET_QSetWorkingDir.
(remote_protocol_features) <QSetWorkingDir>: New entry for
PACKET_QSetWorkingDir.
(extended_remote_set_inferior_cwd): New function.
(extended_remote_create_inferior): Call
"extended_remote_set_inferior_cwd".
(_initialize_remote): Call "add_packet_config_cmd" for
QSetWorkingDir.
2017-10-04 Sergio Durigan Junior <sergiodj@redhat.com>
* NEWS (New commands): Mention "set/show cwd".

10
gdb/NEWS
View File

@ -26,6 +26,12 @@
* New features in the GDB remote stub, GDBserver
** GDBserver is now able to start inferior processes with a
specified initial working directory.
The user can set the desired working directory to be used from
GDB using the new "set cwd" command.
** New "--selftest" command line option runs some GDBserver self
tests. These self tests are disabled in releases.
@ -59,6 +65,10 @@ QEnvironmentReset
QStartupWithShell
Indicates whether the inferior must be started with a shell or not.
QSetWorkingDir
Tell GDBserver that the inferior to be started should use a specific
working directory.
* The "maintenance print c-tdesc" command now takes an optional
argument which is the file name of XML target description.

4
gdb/common/common-inferior.h
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@ -34,4 +34,8 @@ extern char *get_exec_file (int err);
been set, then return NULL. */
extern const char *get_inferior_cwd ();
/* Set the inferior current working directory. If CWD is NULL, unset
the directory. */
extern void set_inferior_cwd (const char *cwd);
#endif /* ! COMMON_INFERIOR_H */

11
gdb/doc/ChangeLog
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@ -1,3 +1,14 @@
2017-10-04 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.texinfo (Starting your Program) <The working directory.>:
Mention remote debugging.
(Working Directory) <Your Program's Working Directory>:
Likewise.
(Connecting) <Remote Packet>: Add "set-working-dir"
and "QSetWorkingDir" to the table.
(Remote Protocol) <QSetWorkingDir>: New item, explaining the
packet.
2017-10-04 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.texinfo (Starting your Program) <The working directory.>:

36
gdb/doc/gdb.texinfo
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@ -2059,8 +2059,10 @@ your program. @xref{Environment, ,Your Program's Environment}.
@item The @emph{working directory.}
You can set your program's working directory with the command
@kbd{set cwd}. If you do not set any working directory with this
command, your program will inherit @value{GDBN}'s working directory.
@xref{Working Directory, ,Your Program's Working Directory}.
command, your program will inherit @value{GDBN}'s working directory if
native debugging, or the remote server's working directory if remote
debugging. @xref{Working Directory, ,Your Program's Working
Directory}.
@item The @emph{standard input and output.}
Your program normally uses the same device for standard input and
@ -2439,7 +2441,9 @@ Each time you start your program with @code{run}, the inferior will be
initialized with the current working directory specified by the
@kbd{set cwd} command. If no directory has been specified by this
command, then the inferior will inherit @value{GDBN}'s current working
directory as its working directory.
directory as its working directory if native debugging, or it will
inherit the remote server's current working directory if remote
debugging.
@table @code
@kindex set cwd
@ -21003,6 +21007,10 @@ are:
@tab @code{QEnvironmentReset}
@tab @code{Reset the inferior environment (i.e., unset user-set variables)}
@item @code{set-working-dir}
@tab @code{QSetWorkingDir}
@tab @code{set cwd}
@item @code{conditional-breakpoints-packet}
@tab @code{Z0 and Z1}
@tab @code{Support for target-side breakpoint condition evaluation}
@ -36860,6 +36868,28 @@ by supplying an appropriate @samp{qSupported} response
actually support passing environment variables to the starting
inferior.
@item QSetWorkingDir:@r{[}@var{directory}@r{]}
@anchor{QSetWorkingDir packet}
@cindex set working directory, remote request
@cindex @samp{QSetWorkingDir} packet
This packet is used to inform the remote server of the intended
current working directory for programs that are going to be executed.
The packet is composed by @var{directory}, an hex encoded
representation of the directory that the remote inferior will use as
its current working directory. If @var{directory} is an empty string,
the remote server should reset the inferior's current working
directory to its original, empty value.
This packet is only available in extended mode (@pxref{extended
mode}).
Reply:
@table @samp
@item OK
The request succeeded.
@end table
@item qfThreadInfo
@itemx qsThreadInfo
@cindex list active threads, remote request

8
gdb/gdbserver/ChangeLog
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@ -1,3 +1,11 @@
2017-10-04 Sergio Durigan Junior <sergiodj@redhat.com>
* inferiors.c (set_inferior_cwd): New function.
* server.c (handle_general_set): Handle QSetWorkingDir packet.
(handle_query): Inform that QSetWorkingDir is supported.
* win32-low.c (create_process): Pass the inferior's cwd to
CreateProcess.
2017-10-04 Sergio Durigan Junior <sergiodj@redhat.com>
* inferiors.c (current_inferior_cwd): New global variable.

12
gdb/gdbserver/inferiors.c
View File

@ -456,3 +456,15 @@ get_inferior_cwd ()
{
return current_inferior_cwd;
}
/* See common/common-inferior.h. */
void
set_inferior_cwd (const char *cwd)
{
xfree ((void *) current_inferior_cwd);
if (cwd != NULL)
current_inferior_cwd = xstrdup (cwd);
else
current_inferior_cwd = NULL;
}

32
gdb/gdbserver/server.c
View File

@ -869,6 +869,35 @@ handle_general_set (char *own_buf)
return;
}
if (startswith (own_buf, "QSetWorkingDir:"))
{
const char *p = own_buf + strlen ("QSetWorkingDir:");
if (*p != '\0')
{
std::string path = hex2str (p);
set_inferior_cwd (path.c_str ());
if (remote_debug)
debug_printf (_("[Set the inferior's current directory to %s]\n"),
path.c_str ());
}
else
{
/* An empty argument means that we should clear out any
previously set cwd for the inferior. */
set_inferior_cwd (NULL);
if (remote_debug)
debug_printf (_("\
[Unset the inferior's current directory; will use gdbserver's cwd]\n"));
}
write_ok (own_buf);
return;
}
/* Otherwise we didn't know what packet it was. Say we didn't
understand it. */
own_buf[0] = 0;
@ -2351,7 +2380,8 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
sprintf (own_buf,
"PacketSize=%x;QPassSignals+;QProgramSignals+;"
"QStartupWithShell+;QEnvironmentHexEncoded+;"
"QEnvironmentReset+;QEnvironmentUnset+",
"QEnvironmentReset+;QEnvironmentUnset+;"
"QSetWorkingDir+",
PBUFSIZ - 1);
if (target_supports_catch_syscall ())

22
gdb/gdbserver/win32-low.c
View File

@ -32,6 +32,7 @@
#include <tlhelp32.h>
#include <psapi.h>
#include <process.h>
#include "gdb_tilde_expand.h"
#ifndef USE_WIN32API
#include <sys/cygwin.h>
@ -562,10 +563,12 @@ static BOOL
create_process (const char *program, char *args,
DWORD flags, PROCESS_INFORMATION *pi)
{
const char *inferior_cwd = get_inferior_cwd ();
std::string expanded_infcwd = gdb_tilde_expand (inferior_cwd);
BOOL ret;
#ifdef _WIN32_WCE
wchar_t *p, *wprogram, *wargs;
wchar_t *p, *wprogram, *wargs, *wcwd = NULL;
size_t argslen;
wprogram = alloca ((strlen (program) + 1) * sizeof (wchar_t));
@ -579,6 +582,19 @@ create_process (const char *program, char *args,
wargs = alloca ((argslen + 1) * sizeof (wchar_t));
mbstowcs (wargs, args, argslen + 1);
if (inferior_cwd != NULL)
{
std::replace (expanded_infcwd.begin (), expanded_infcwd.end (),
'/', '\\');
wcwd = alloca ((expanded_infcwd.size () + 1) * sizeof (wchar_t));
if (mbstowcs (wcwd, expanded_infcwd.c_str (),
expanded_infcwd.size () + 1) == NULL)
{
error (_("\
Could not convert the expanded inferior cwd to wide-char."));
}
}
ret = CreateProcessW (wprogram, /* image name */
wargs, /* command line */
NULL, /* security, not supported */
@ -586,7 +602,7 @@ create_process (const char *program, char *args,
FALSE, /* inherit handles, not supported */
flags, /* start flags */
NULL, /* environment, not supported */
NULL, /* current directory, not supported */
wcwd, /* current directory */
NULL, /* start info, not supported */
pi); /* proc info */
#else
@ -599,7 +615,7 @@ create_process (const char *program, char *args,
TRUE, /* inherit handles */
flags, /* start flags */
NULL, /* environment */
NULL, /* current directory */
expanded_infcwd.c_str (), /* current directory */
&si, /* start info */
pi); /* proc info */
#endif

8
gdb/infcmd.c
View File

@ -242,10 +242,9 @@ show_args_command (struct ui_file *file, int from_tty,
deprecated_show_value_hack (file, from_tty, c, get_inferior_args ());
}
/* Set the inferior current working directory. If CWD is NULL, unset
the directory. */
/* See common/common-inferior.h. */
static void
void
set_inferior_cwd (const char *cwd)
{
struct inferior *inf = current_inferior ();
@ -289,7 +288,8 @@ show_cwd_command (struct ui_file *file, int from_tty,
fprintf_filtered (gdb_stdout,
_("\
You have not set the inferior's current working directory.\n\
The inferior will inherit GDB's cwd.\n"));
The inferior will inherit GDB's cwd if native debugging, or the remote\n\
server's cwd if remote debugging.\n"));
else
fprintf_filtered (gdb_stdout,
_("Current working directory that will be used "

47
gdb/remote.c
View File

@ -1430,6 +1430,7 @@ enum {
PACKET_QPassSignals,
PACKET_QCatchSyscalls,
PACKET_QProgramSignals,
PACKET_QSetWorkingDir,
PACKET_QStartupWithShell,
PACKET_QEnvironmentHexEncoded,
PACKET_QEnvironmentReset,
@ -4662,6 +4663,8 @@ static const struct protocol_feature remote_protocol_features[] = {
PACKET_QCatchSyscalls },
{ "QProgramSignals", PACKET_DISABLE, remote_supported_packet,
PACKET_QProgramSignals },
{ "QSetWorkingDir", PACKET_DISABLE, remote_supported_packet,
PACKET_QSetWorkingDir },
{ "QStartupWithShell", PACKET_DISABLE, remote_supported_packet,
PACKET_QStartupWithShell },
{ "QEnvironmentHexEncoded", PACKET_DISABLE, remote_supported_packet,
@ -9641,6 +9644,45 @@ extended_remote_environment_support (struct remote_state *rs)
send_environment_packet (rs, "unset", "QEnvironmentUnset", el.c_str ());
}
/* Helper function to set the current working directory for the
inferior in the remote target. */
static void
extended_remote_set_inferior_cwd (struct remote_state *rs)
{
if (packet_support (PACKET_QSetWorkingDir) != PACKET_DISABLE)
{
const char *inferior_cwd = get_inferior_cwd ();
if (inferior_cwd != NULL)
{
std::string hexpath = bin2hex ((const gdb_byte *) inferior_cwd,
strlen (inferior_cwd));
xsnprintf (rs->buf, get_remote_packet_size (),
"QSetWorkingDir:%s", hexpath.c_str ());
}
else
{
/* An empty inferior_cwd means that the user wants us to
reset the remote server's inferior's cwd. */
xsnprintf (rs->buf, get_remote_packet_size (),
"QSetWorkingDir:");
}
putpkt (rs->buf);
getpkt (&rs->buf, &rs->buf_size, 0);
if (packet_ok (rs->buf,
&remote_protocol_packets[PACKET_QSetWorkingDir])
!= PACKET_OK)
error (_("\
Remote replied unexpectedly while setting the inferior's working\n\
directory: %s"),
rs->buf);
}
}
/* In the extended protocol we want to be able to do things like
"run" and have them basically work as expected. So we need
a special create_inferior function. We support changing the
@ -9683,6 +9725,8 @@ Remote replied unexpectedly while setting startup-with-shell: %s"),
extended_remote_environment_support (rs);
extended_remote_set_inferior_cwd (rs);
/* Now restart the remote server. */
run_worked = extended_remote_run (args) != -1;
if (!run_worked)
@ -14190,6 +14234,9 @@ Show the maximum size of the address (in bits) in a memory packet."), NULL,
add_packet_config_cmd (&remote_protocol_packets[PACKET_QProgramSignals],
"QProgramSignals", "program-signals", 0);
add_packet_config_cmd (&remote_protocol_packets[PACKET_QSetWorkingDir],
"QSetWorkingDir", "set-working-dir", 0);
add_packet_config_cmd (&remote_protocol_packets[PACKET_QStartupWithShell],
"QStartupWithShell", "startup-with-shell", 0);

5
gdb/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2017-10-04 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.base/set-cwd.exp: Make it available on
native-extended-gdbserver.
2017-10-04 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.base/set-cwd.c: New file.

4
gdb/testsuite/gdb.base/set-cwd.exp
View File

@ -15,8 +15,8 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
if { [use_gdb_stub] || [target_info gdb_protocol] == "extended-remote" } {
untested "not implemented on remote servers"
if { [use_gdb_stub] } {
untested "skipping tests due to use_gdb_stub"
return
}