From 7dbac825b09f0847e608b50c80db816ef20d9315 Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Thu, 10 May 2018 10:24:33 -0500 Subject: [PATCH] gdbserver/Windows: Fix "no program to debug" error Trying to start a program with GDBserver on Windows yields the following error: $ gdbserver.exe --once :4444 simple_main.exe Killing process(es): 5008 No program to debug Exiting The error itself comes from the following code shortly after create_inferior gets called (in server.c::main): /* Wait till we are at first instruction in program. */ create_inferior (program_path.get (), program_args); [...] if (last_status.kind == TARGET_WAITKIND_EXITED || last_status.kind == TARGET_WAITKIND_SIGNALLED) was_running = 0; else was_running = 1; if (!was_running && !multi_mode) error ("No program to debug"); What happens is that the "last_status" global starts initialized as zeroes, which means last_status.kind == TARGET_WAITKIND_EXITED, and we expect create_inferior to be waiting for the inferior to start until reaching the SIGTRAP, and to set the "last_status" global to match that last event we received. I suspect this is an unintended side-effect of the following change... commit 2090129c36c7e582943b7d300968d19b46160d84 Date: Thu Dec 22 21:11:11 2016 -0500 Subject: Share fork_inferior et al with gdbserver ... which removes some code in server.c that was responsible for starting the inferior in a functin that was named start_inferior, and looked like this: signal_pid = create_inferior (new_argv[0], &new_argv[0]); [...] /* Wait till we are at 1st instruction in program, return new pid (assuming success). */ last_ptid = mywait (pid_to_ptid (signal_pid), &last_status, 0, 0); The code has been transitioned to using fork_inferior, but sadly, only for the targets that support it. On Windows, the calls to wait setting "last_status" simply disappeared. This patch adds it back in the Windows-specific implementation of create_inferior. gdb/gdbserver/ChangeLog: PR server/23158: * win32-low.c (win32_create_inferior): Add call to my_wait setting last_status global. --- gdb/gdbserver/ChangeLog | 6 ++++++ gdb/gdbserver/win32-low.c | 4 ++++ 2 files changed, 10 insertions(+) diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index 30c7eff72c3..6b6f8fc349a 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,9 @@ +2018-05-10 Joel Brobecker + + PR server/23158: + * win32-low.c (win32_create_inferior): Add call to my_wait + setting last_status global. + 2018-05-10 Joel Brobecker PR server/23158: diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c index db5dd49eedf..7ed5fc5c0e7 100644 --- a/gdb/gdbserver/win32-low.c +++ b/gdb/gdbserver/win32-low.c @@ -704,6 +704,10 @@ win32_create_inferior (const char *program, do_initial_child_stuff (pi.hProcess, pi.dwProcessId, 0); + /* Wait till we are at 1st instruction in program, return new pid + (assuming success). */ + last_ptid = win32_wait (pid_to_ptid (current_process_id), &last_status, 0); + return current_process_id; } -- 2.30.2