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[binutils-gdb] gdbserver/Windows: Fix "no program to debug" error
- From: Joel Brobecker <brobecke at sourceware dot org>
- To: gdb-cvs at sourceware dot org
- Date: 10 May 2018 15:28:19 -0000
- Subject: [binutils-gdb] gdbserver/Windows: Fix "no program to debug" error
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=7dbac825b09f0847e608b50c80db816ef20d9315
commit 7dbac825b09f0847e608b50c80db816ef20d9315
Author: Joel Brobecker <brobecker@adacore.com>
Date: Thu May 10 10:24:33 2018 -0500
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.
Diff:
---
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 30c7eff..6b6f8fc 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,6 +1,12 @@
2018-05-10 Joel Brobecker <brobecker@adacore.com>
PR server/23158:
+ * win32-low.c (win32_create_inferior): Add call to my_wait
+ setting last_status global.
+
+2018-05-10 Joel Brobecker <brobecker@adacore.com>
+
+ PR server/23158:
* win32-low.c (create_process): Only call gdb_tilde_expand if
inferior_cwd is not NULL.
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index db5dd49..7ed5fc5 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;
}