From 8e9119a807df510f0d2ce4cdda3078166d6e99a7 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 24 Feb 2020 15:30:06 +0100 Subject: [PATCH] hmp: Fail gracefully if chardev is already in use Trying to attach a HMP monitor to a chardev that is already in use results in a crash because monitor_init_hmp() passes &error_abort to qemu_chr_fe_init(): $ ./x86_64-softmmu/qemu-system-x86_64 --chardev stdio,id=foo --mon foo --mon foo QEMU 4.2.50 monitor - type 'help' for more information (qemu) Unexpected error in qemu_chr_fe_init() at chardev/char-fe.c:220: qemu-system-x86_64: --mon foo: Device 'foo' is in use Abgebrochen (Speicherabzug geschrieben) Fix this by allowing monitor_init_hmp() to return an error and passing any error in qemu_chr_fe_init() to its caller instead of aborting. Signed-off-by: Kevin Wolf Message-Id: <20200224143008.13362-19-kwolf@redhat.com> Acked-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- chardev/char.c | 8 +++++++- gdbstub.c | 2 +- include/monitor/monitor.h | 2 +- monitor/hmp.c | 8 ++++++-- monitor/monitor.c | 2 +- stubs/monitor.c | 2 +- tests/test-util-sockets.c | 2 +- 7 files changed, 18 insertions(+), 8 deletions(-) diff --git a/chardev/char.c b/chardev/char.c index 87237568df..e77564060d 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -737,7 +737,13 @@ Chardev *qemu_chr_new_noreplay(const char *label, const char *filename, if (qemu_opt_get_bool(opts, "mux", 0)) { assert(permit_mux_mon); - monitor_init_hmp(chr, true); + monitor_init_hmp(chr, true, &err); + if (err) { + error_report_err(err); + object_unparent(OBJECT(chr)); + chr = NULL; + goto out; + } } out: diff --git a/gdbstub.c b/gdbstub.c index ce304ff482..22a2d630cd 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -3367,7 +3367,7 @@ int gdbserver_start(const char *device) /* Initialize a monitor terminal for gdb */ mon_chr = qemu_chardev_new(NULL, TYPE_CHARDEV_GDB, NULL, NULL, &error_abort); - monitor_init_hmp(mon_chr, false); + monitor_init_hmp(mon_chr, false, &error_abort); } else { qemu_chr_fe_deinit(&s->chr, true); mon_chr = s->mon_chr; diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h index e55a3b57e0..ad823b9edb 100644 --- a/include/monitor/monitor.h +++ b/include/monitor/monitor.h @@ -18,7 +18,7 @@ bool monitor_cur_is_qmp(void); void monitor_init_globals(void); void monitor_init_globals_core(void); void monitor_init_qmp(Chardev *chr, bool pretty, Error **errp); -void monitor_init_hmp(Chardev *chr, bool use_readline); +void monitor_init_hmp(Chardev *chr, bool use_readline, Error **errp); int monitor_init(MonitorOptions *opts, Error **errp); int monitor_init_opts(QemuOpts *opts, Error **errp); void monitor_cleanup(void); diff --git a/monitor/hmp.c b/monitor/hmp.c index 944fa9651e..d598dd02bb 100644 --- a/monitor/hmp.c +++ b/monitor/hmp.c @@ -1399,12 +1399,16 @@ static void monitor_readline_flush(void *opaque) monitor_flush(&mon->common); } -void monitor_init_hmp(Chardev *chr, bool use_readline) +void monitor_init_hmp(Chardev *chr, bool use_readline, Error **errp) { MonitorHMP *mon = g_new0(MonitorHMP, 1); + if (!qemu_chr_fe_init(&mon->common.chr, chr, errp)) { + g_free(mon); + return; + } + monitor_data_init(&mon->common, false, false, false); - qemu_chr_fe_init(&mon->common.chr, chr, &error_abort); mon->use_readline = use_readline; if (mon->use_readline) { diff --git a/monitor/monitor.c b/monitor/monitor.c index 00d287655e..2282bf6780 100644 --- a/monitor/monitor.c +++ b/monitor/monitor.c @@ -631,7 +631,7 @@ int monitor_init(MonitorOptions *opts, Error **errp) warn_report("'pretty' is deprecated for HMP monitors, it has no " "effect and will be removed in future versions"); } - monitor_init_hmp(chr, true); + monitor_init_hmp(chr, true, &local_err); break; default: g_assert_not_reached(); diff --git a/stubs/monitor.c b/stubs/monitor.c index 9403f8e72c..20786ac4ff 100644 --- a/stubs/monitor.c +++ b/stubs/monitor.c @@ -9,7 +9,7 @@ int monitor_get_fd(Monitor *mon, const char *name, Error **errp) return -1; } -void monitor_init_hmp(Chardev *chr, bool use_readline) +void monitor_init_hmp(Chardev *chr, bool use_readline, Error **errp) { } diff --git a/tests/test-util-sockets.c b/tests/test-util-sockets.c index 2edb4c539d..5fd947c7bf 100644 --- a/tests/test-util-sockets.c +++ b/tests/test-util-sockets.c @@ -72,7 +72,7 @@ int monitor_get_fd(Monitor *mon, const char *fdname, Error **errp) __thread Monitor *cur_mon; int monitor_vprintf(Monitor *mon, const char *fmt, va_list ap) { abort(); } void monitor_init_qmp(Chardev *chr, bool pretty, Error **errp) {} -void monitor_init_hmp(Chardev *chr, bool use_readline) {} +void monitor_init_hmp(Chardev *chr, bool use_readline, Error **errp) {} static void test_socket_fd_pass_name_good(void) -- 2.11.0