From 4c35c4c6a779c79e456b7a5311f74aafc9026bd5 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Sun, 27 Nov 2022 10:31:50 +0100 Subject: [PATCH] [gdb/server] Emit warning for SIGINT failure Consider the executable from test-case gdb.base/interrupt-daemon.exp. When starting it using gdbserver: ... $ ./build/gdbserver/gdbserver localhost:2345 \ ./outputs/gdb.base/interrupt-daemon/interrupt-daemon ... and connecting to it using gdb: ... $ gdb -q -ex "target remote localhost:2345" \ -ex "set follow-fork-mode child" \ -ex "break daemon_main" -ex cont ... we are setup to do the same as in the test-case: interrupt a running inferior using ^C. So let's try: ... (gdb) continue Continuing. ^C ... After pressing ^C, nothing happens. This a known problem, filed as PR remote/18772. The problem is that in linux_process_target::request_interrupt, a kill is used to send a SIGINT, but it fails. And it fails silently. Make the failure verbose by adding a warning, such that the gdbserver output becomes more helpful: ... Process interrupt-daemon created; pid = 15068 Listening on port 2345 Remote debugging from host ::1, port 35148 Detaching from process 15068 Detaching from process 15085 gdbserver: Sending SIGINT to process group of pid 15068 failed: \ No such process ... Note that the failure can easily be reproduced using the test-case and target board native-gdbserver: ... (gdb) continue^M Continuing.^M PASS: gdb.base/interrupt-daemon.exp: fg: continue ^CFAIL: gdb.base/interrupt-daemon.exp: fg: ctrl-c stops process (timeout) ... as reported in PR server/23382. Tested on x86_64-linux. Approved-By: Simon Marchi --- gdbserver/linux-low.cc | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc index a896b37528b..6f96e16d6f0 100644 --- a/gdbserver/linux-low.cc +++ b/gdbserver/linux-low.cc @@ -5467,7 +5467,10 @@ linux_process_target::request_interrupt () { /* Send a SIGINT to the process group. This acts just like the user typed a ^C on the controlling terminal. */ - ::kill (-signal_pid, SIGINT); + int res = ::kill (-signal_pid, SIGINT); + if (res == -1) + warning (_("Sending SIGINT to process group of pid %ld failed: %s"), + signal_pid, safe_strerror (errno)); } bool -- 2.30.2