gdbserver: Fix qSupported:xmlRegisters=i386;UnknownFeature+ handling
authorPedro Alves <palves@redhat.com>
Thu, 19 Nov 2015 18:31:50 +0000 (18:31 +0000)
committerPedro Alves <palves@redhat.com>
Thu, 19 Nov 2015 18:32:55 +0000 (18:32 +0000)
commit06e03fff313dfcc5f344280f8ac70b0ec8521f3a
tree87cfec6774afc96d69062e21c5087077b82e4c04
parentb35d5edb03798388d503d922d8f909a133bf93dd
gdbserver: Fix qSupported:xmlRegisters=i386;UnknownFeature+ handling

The target_process_qsupported method is called for each qSupported
feature that the common code does not recognize.  The only current
implementation, for x86 Linux (x86_linux_process_qsupported), assumes
that it either is called with the "xmlRegisters=i386" feature, or that
it is isn't called at all, indicating the connected GDB predates x86
XML descriptions.

That's a bad assumption however.  If GDB sends in a new/unknown (to
core gdbserver) feature after "xmlRegisters=i386", say, something like
qSupported:xmlRegisters=i386;UnknownFeature+, then when
target_process_qsupported is called for "UnknownFeature+",
x86_linux_process_qsupported clears the 'use_xml' global and calls
x86_linux_update_xmltarget, and gdbserver ends up _not_ reporting a
XML description...

This commit changes the target_process_qsupported API to instead pass
down a vector of unprocessed qSupported features in one go.

(There's an early call to target_process_qsupported(NULL) that
indicates "starting qSupported processing".  There's no matching call
to mark the end of processing, though.  I first fixed this by passing
(char *)-1 to indicate that, and adjusted the x86 backend to only
clear 'use_xml' when qSupported processing starts, and then only call
x86_linux_update_xmltarget() when (char *)-1 was passed.  However, I
wasn't that happy with the hack and came up this alternative version.)

gdb/gdbserver/ChangeLog:
2015-11-19  Pedro Alves  <palves@redhat.com>

* linux-low.c (linux_process_qsupported): Change prototype.
Adjust.
* linux-low.h (struct linux_target_ops) <process_qsupported>:
Change prototype.
* linux-x86-low.c (x86_linux_process_qsupported): Change prototype
and adjust to loop over all features.
* server.c (handle_query) <qSupported>: Adjust to call
target_process_qsupported once, passing it a vector of unprocessed
features.
* target.h (struct target_ops) <process_qsupported>: Change
prototype.
(target_process_qsupported): Adjust.
gdb/gdbserver/ChangeLog
gdb/gdbserver/linux-low.c
gdb/gdbserver/linux-low.h
gdb/gdbserver/linux-x86-low.c
gdb/gdbserver/server.c
gdb/gdbserver/target.h