Dominik 'Disconnect3d' Czarnota <dominik.b.czarn...@gmail.com> writes:
> This patch adds support for the `qqemu.Pid` packet to the qemu > gdbstub which can be used by clients to get the QEMU process PID. > > This is useful for plugins like Pwndbg [0] or gdb-pt-dump in order to > inspect the QEMU process memory through the /proc/self/{maps,mem} > interfaces. Without this feature, they have to rely on doing an > unreliable pgrep/ps output processing. That seems a little thin a reason for QEMU to expose its own PID. For user-mode you can already get that detail through anything using gdb_append_thread_id(). For system-mode leaking QEMU's own pid seems like an information leak at best. There are modes like semihosting which give a remote even more power but you need to at least opt in to that. > > This patch has been developed by Patryk, who I included in the > Co-authored-by and who asked me to send the patch. > > [0] https://github.com/pwndbg/pwndbg > [1] https://github.com/martinradev/gdb-pt-dump > > Co-authored-by: Patryk 'patryk4815' Sondej <patryk.son...@gmail.com> > Signed-off-by: Dominik 'Disconnect3d' Czarnota <dominik.b.czarn...@gmail.com> > --- > gdbstub/gdbstub.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c > index 282e13e163..a077c2c5ed 100644 > --- a/gdbstub/gdbstub.c > +++ b/gdbstub/gdbstub.c > @@ -1746,6 +1746,12 @@ static void handle_query_qemu_supported(GArray > *params, void *user_ctx) > gdb_put_strbuf(); > } > > +static void handle_query_qemu_pid(GArray *params, void *user_ctx) > +{ > + g_string_printf(gdbserver_state.str_buf, "F%x", getpid()); > + gdb_put_strbuf(); > +} > + > static const GdbCmdParseEntry gdb_gen_query_set_common_table[] = { > /* Order is important if has same prefix */ > { > @@ -1902,6 +1908,10 @@ static const GdbCmdParseEntry gdb_gen_query_table[] = { > .handler = handle_query_qemu_supported, > .cmd = "qemu.Supported", > }, > + { > + .handler = handle_query_qemu_pid, > + .cmd = "qemu.Pid", > + }, > #ifndef CONFIG_USER_ONLY > { > .handler = gdb_handle_query_qemu_phy_mem_mode, -- Alex Bennée Virtualisation Tech Lead @ Linaro