[PATCH 2/3] [gdb/testsuite] Kill left-over process in gdb.base/add-symbol-file-attach.exp

[Tom de Vries <tdevries@suse.de>]

When running test-case gdb.base/add-symbol-file-attach.exp, the process
spawned by:
...
set test_spawn_id [spawn_wait_for_attach $binfile]
...
is not cleaned up.

The usual way to fix this is to add "kill_wait_spawned_process $test_spawn_id"
at the end of the test-case.

However, that doesn't look robust enough to me: in case of running into some
form of trouble in the test-case, that cleanup may not be reached.

I considered adding a wrapper proc like save_vars, but that makes fixing this
a bit intrusive since it requires re-indenting most of the test-case.

Instead, add a new proc at_finish_kill_wait:
...
 set test_spawn_id [spawn_wait_for_attach $binfile]
+at_finish_kill_wait $test_spawn_id
...
that schedules the cleanup for test-case finish.

While we're at it, make sure that we check for the result of
spawn_wait_for_attach, and since this:
...
UNSUPPORTED: $exp: require failed: !string equal $test_spawn_id "-1"
...
is somewhat hard to parse, add proc valid_spawn_id to get the more readable:
...
UNSUPPORTED: $exp: require failed: valid_spawn_id $test_spawn_id
...

Tested on x86_64-linux.

PR testsuite/32709
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32709
---
 .../gdb.base/add-symbol-file-attach.exp       |  3 +++
 gdb/testsuite/lib/gdb.exp                     | 21 +++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/gdb/testsuite/gdb.base/add-symbol-file-attach.exp b/gdb/testsuite/gdb.base/add-symbol-file-attach.exp
index e39a26ab666..97e0e018fc7 100644
--- a/gdb/testsuite/gdb.base/add-symbol-file-attach.exp
+++ b/gdb/testsuite/gdb.base/add-symbol-file-attach.exp
@@ -44,6 +44,9 @@ if {[build_executable $testfile.exp $testfile $srcfile debug] == -1} {
 # so that GDB may attach to it.
 
 set test_spawn_id [spawn_wait_for_attach $binfile]
+require {valid_spawn_id $test_spawn_id}
+at_finish_kill_wait $test_spawn_id
+
 set testpid [spawn_id_get_pid $test_spawn_id]
 
 gdb_start
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index d4634c85725..7c2d185b690 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -101,6 +101,16 @@ append_environment_default ASAN_OPTIONS detect_leaks 0
 # List of procs to run in gdb_finish.
 set gdb_finish_hooks [list]
 
+# List of spawn_ids to kill-and-wait-for-exit in gdb_finish.
+set gdb_finish_kill_wait {}
+
+# Schedule each arg for kill-and-wait-for-exit in gdb_finish.
+proc at_finish_kill_wait { args } {
+    foreach arg $args {
+	lappend ::gdb_finish_kill_wait $arg
+    }
+}
+
 # Variable in which we keep track of globals that are allowed to be live
 # across test-cases.
 array set gdb_persistent_globals {}
@@ -6913,6 +6923,12 @@ proc spawn_wait_for_attach { executable_list } {
     return [spawn_wait_for_attach_1 $executable_list]
 }
 
+# Return 1 if SPAWN_ID is a valid spawn id.
+
+proc valid_spawn_id { spawn_id } {
+    return [expr ![string equal $spawn_id "-1"]]
+}
+
 #
 # gdb_load_cmd -- load a file into the debugger.
 #		  ARGS - additional args to load command.
@@ -7884,6 +7900,11 @@ proc gdb_finish { } {
     set gdb_finish_hooks [list]
 
     gdb_cleanup_globals
+
+    foreach spawn_id $::gdb_finish_kill_wait {
+	kill_wait_spawned_process $spawn_id
+    }
+    set ::gdb_finish_kill_wait {}
 }
 
 global debug_format
-- 
2.43.0