The upcoming follow-fork-mode child support needs to perform certain
actions when GDB detaches from the stopped parent or the stopped child.
Introduce a user-specific hook for this.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 gdbstub/gdbstub.c   | 6 ++++++
 gdbstub/internals.h | 1 +
 gdbstub/user.c      | 5 +++++
 3 files changed, 12 insertions(+)

diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
index adcd977cd57..46f5dd47e9e 100644
--- a/gdbstub/gdbstub.c
+++ b/gdbstub/gdbstub.c
@@ -991,6 +991,12 @@ static void handle_detach(GArray *params, void *user_ctx)
         pid = get_param(params, 0)->val_ul;
     }
 
+#ifdef CONFIG_USER_ONLY
+    if (gdb_handle_detach_user(pid)) {
+        return;
+    }
+#endif
+
     process = gdb_get_process(pid);
     gdb_process_breakpoint_remove_all(process);
     process->attached = false;
diff --git a/gdbstub/internals.h b/gdbstub/internals.h
index b4905c7181a..b4724598384 100644
--- a/gdbstub/internals.h
+++ b/gdbstub/internals.h
@@ -198,6 +198,7 @@ void gdb_handle_query_xfer_exec_file(GArray *params, void *user_ctx); /* user */
 void gdb_handle_set_catch_syscalls(GArray *params, void *user_ctx); /* user */
 void gdb_handle_query_supported_user(const char *gdb_supported); /* user */
 bool gdb_handle_set_thread_user(uint32_t pid, uint32_t tid); /* user */
+bool gdb_handle_detach_user(uint32_t pid); /* user */
 
 void gdb_handle_query_attached(GArray *params, void *user_ctx); /* both */
 
diff --git a/gdbstub/user.c b/gdbstub/user.c
index ee6b47b9b9c..6f108e60839 100644
--- a/gdbstub/user.c
+++ b/gdbstub/user.c
@@ -391,6 +391,11 @@ bool gdb_handle_set_thread_user(uint32_t pid, uint32_t tid)
     return false;
 }
 
+bool gdb_handle_detach_user(uint32_t pid)
+{
+    return false;
+}
+
 /*
  * Execution state helpers
  */
-- 
2.43.0