[PATCH v2 36/47] linux-nat: Factor out get_detach_signal code to common code

Pedro Alves
2025-05-19T13:36:57Z

The Windows target backend will want to do most of what the
get_detach_signal function in gdb/linux-nat.c does, except for the
Linux-specific bits. This commit moves the code that is shareable to
infrun.c, so that other targets can use it too.

Change-Id: Ifaa96b4a41bb83d868079af4d47633715c0e1940
---
gdb/infrun.c | 37 +++++++++++++++++++++++++++++++++++++
gdb/infrun.h | 6 ++++++
gdb/linux-nat.c | 41 +++++------------------------------------
3 files changed, 48 insertions(+), 36 deletions(-)

diff --git a/gdb/infrun.c b/gdb/infrun.c
index 20649ace942..826093f79f9 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -367,6 +367,43 @@ update_signals_program_target (void)
target_program_signals (signal_program);
}

+/* See infrun.h. */
+
+gdb_signal
+get_detach_signal (process_stratum_target *proc_target, ptid_t ptid)
+{
+ thread_info *tp = proc_target->find_thread (ptid);
+ gdb_signal signo = GDB_SIGNAL_0;
+
+ if (target_is_non_stop_p ()
+ && tp->internal_state () != THREAD_INT_RUNNING)
+ {
+ if (tp->has_pending_waitstatus ())
+ {
+ /* If the thread has a pending event, and it was stopped
+ with a signal, use that signal to resume it. If it has a
+ pending event of another kind, it was not stopped with a
+ signal, so resume it without a signal. */
+ if (tp->pending_waitstatus ().kind () == TARGET_WAITKIND_STOPPED)
+ signo = tp->pending_waitstatus ().sig ();
+ }
+ else
+ signo = tp->stop_signal ();
+ }
+ else if (!target_is_non_stop_p ())
+ {
+ ptid_t last_ptid;
+ process_stratum_target *last_target;
+
+ get_last_target_status (&last_target, &last_ptid, nullptr);
+
+ if (last_target == proc_target && ptid == last_ptid)
+ signo = tp->stop_signal ();
+ }
+
+ return signo;
+}
+
/* Value to pass to target_resume() to cause all threads to resume. */

#define RESUME_ALL minus_one_ptid
diff --git a/gdb/infrun.h b/gdb/infrun.h
index b09e7c1df8a..869ae2a67a9 100644
--- a/gdb/infrun.h
+++ b/gdb/infrun.h
@@ -319,6 +319,12 @@ extern void all_uis_on_sync_execution_starting (void);
detach. */
extern void restart_after_all_stop_detach (process_stratum_target *proc_target);

+/* While detaching, return the signal PTID was supposed to be resumed
+ with, if it were resumed, so we can pass it down to PTID while
+ detaching. */
+extern gdb_signal get_detach_signal (process_stratum_target *proc_target,
+ ptid_t ptid);
+
/* RAII object to temporarily disable the requirement for target
stacks to commit their resumed threads.

diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 4de4cc83cfa..94f3f6c7075 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -1292,13 +1292,13 @@ detach_one_pid (int pid, int signo)
pid, strsignal (signo));
}

-/* Get pending signal of THREAD as a host signal number, for detaching
+/* Get pending signal of LP as a host signal number, for detaching
purposes. This is the signal the thread last stopped for, which we
need to deliver to the thread when detaching, otherwise, it'd be
suppressed/lost. */

static int
-get_detach_signal (struct lwp_info *lp)
+get_lwp_detach_signal (struct lwp_info *lp)
{
enum gdb_signal signo = GDB_SIGNAL_0;

@@ -1328,38 +1328,7 @@ get_detach_signal (struct lwp_info *lp)
else if (lp->status)
signo = gdb_signal_from_host (WSTOPSIG (lp->status));
else
- {
- thread_info *tp = linux_target->find_thread (lp->ptid);
-
- if (target_is_non_stop_p ()
- && tp->internal_state () != THREAD_INT_RUNNING)
- {
- if (tp->has_pending_waitstatus ())
- {
- /* If the thread has a pending event, and it was stopped with a
- signal, use that signal to resume it. If it has a pending
- event of another kind, it was not stopped with a signal, so
- resume it without a signal. */
- if (tp->pending_waitstatus ().kind () == TARGET_WAITKIND_STOPPED)
- signo = tp->pending_waitstatus ().sig ();
- else
- signo = GDB_SIGNAL_0;
- }
- else
- signo = tp->stop_signal ();
- }
- else if (!target_is_non_stop_p ())
- {
- ptid_t last_ptid;
- process_stratum_target *last_target;
-
- get_last_target_status (&last_target, &last_ptid, nullptr);
-
- if (last_target == linux_target
- && lp->ptid.lwp () == last_ptid.lwp ())
- signo = tp->stop_signal ();
- }
- }
+ signo = get_detach_signal (linux_target, lp->ptid);

if (signo == GDB_SIGNAL_0)
{
@@ -1489,7 +1458,7 @@ detach_one_lwp (struct lwp_info *lp, int *signo_p)
if (signo_p == NULL)
{
/* Pass on any pending signal for this LWP. */
- signo = get_detach_signal (lp);
+ signo = get_lwp_detach_signal (lp);
}
else
signo = *signo_p;
@@ -1577,7 +1546,7 @@ linux_nat_target::detach (inferior *inf, int from_tty)
if (main_lwp != nullptr)
{
/* Pass on any pending signal for the last LWP. */
- int signo = get_detach_signal (main_lwp);
+ int signo = get_lwp_detach_signal (main_lwp);

detach_one_lwp (main_lwp, &signo);
}
--
2.49.0