chardev: mark the calls that allow an implicit mux monitor
This is mostly for readability of the code. Let's make it clear which
callers can create an implicit monitor when the chardev is muxed.
This will also enforce a safer behaviour, as we don't really support
creating monitor anywhere/anytime at the moment. Add an assert() to
make sure the programmer explicitely wanted that behaviour.
There are documented cases, such as: -serial/-parallel/-virtioconsole
and to less extent -debugcon.
Less obvious and questionable ones are -gdb, SLIRP -guestfwd and Xen
console. Add a FIXME note for those, but keep the support for now.
Other qemu_chr_new() callers either have a fixed parameter/filename
string or do not need it, such as -qtest:
* qtest.c: qtest_init()
Afaik, only used by tests/libqtest.c, without mux. I don't think we
support it outside of qemu testing: drop support for implicit mux
monitor (qemu_chr_new() call: no implicit mux now).
* hw/
All with literal @filename argument that doesn't enable mux monitor.
* tests/
All with @filename argument that doesn't enable mux monitor.
On a related note, the list of monitor creation places:
- the chardev creators listed above: all from command line (except
perhaps Xen console?)
- -gdb & hmp gdbserver will create a "GDB monitor command" chardev
that is wired to an HMP monitor.
- -mon command line option
From this short study, I would like to think that a monitor may only
be created in the main thread today, though I remain skeptical :)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
diff --git a/chardev/char.c b/chardev/char.c
index 76d866e..e115166 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -329,7 +329,8 @@
return 0;
}
-QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename)
+QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename,
+ bool permit_mux_mon)
{
char host[65], port[33], width[8], height[8];
int pos;
@@ -344,6 +345,10 @@
}
if (strstart(filename, "mon:", &p)) {
+ if (!permit_mux_mon) {
+ error_report("mon: isn't supported in this context");
+ return NULL;
+ }
filename = p;
qemu_opt_set(opts, "mux", "on", &error_abort);
if (strcmp(filename, "stdio") == 0) {
@@ -683,7 +688,8 @@
return chr;
}
-Chardev *qemu_chr_new_noreplay(const char *label, const char *filename)
+Chardev *qemu_chr_new_noreplay(const char *label, const char *filename,
+ bool permit_mux_mon)
{
const char *p;
Chardev *chr;
@@ -694,25 +700,32 @@
return qemu_chr_find(p);
}
- opts = qemu_chr_parse_compat(label, filename);
+ opts = qemu_chr_parse_compat(label, filename, permit_mux_mon);
if (!opts)
return NULL;
chr = qemu_chr_new_from_opts(opts, &err);
- if (err) {
+ if (!chr) {
error_report_err(err);
+ goto out;
}
- if (chr && qemu_opt_get_bool(opts, "mux", 0)) {
+
+ if (qemu_opt_get_bool(opts, "mux", 0)) {
+ assert(permit_mux_mon);
monitor_init(chr, MONITOR_USE_READLINE);
}
+
+out:
qemu_opts_del(opts);
return chr;
}
-Chardev *qemu_chr_new(const char *label, const char *filename)
+static Chardev *qemu_chr_new_permit_mux_mon(const char *label,
+ const char *filename,
+ bool permit_mux_mon)
{
Chardev *chr;
- chr = qemu_chr_new_noreplay(label, filename);
+ chr = qemu_chr_new_noreplay(label, filename, permit_mux_mon);
if (chr) {
if (replay_mode != REPLAY_MODE_NONE) {
qemu_chr_set_feature(chr, QEMU_CHAR_FEATURE_REPLAY);
@@ -726,6 +739,16 @@
return chr;
}
+Chardev *qemu_chr_new(const char *label, const char *filename)
+{
+ return qemu_chr_new_permit_mux_mon(label, filename, false);
+}
+
+Chardev *qemu_chr_new_mux_mon(const char *label, const char *filename)
+{
+ return qemu_chr_new_permit_mux_mon(label, filename, true);
+}
+
static int qmp_query_chardev_foreach(Object *obj, void *data)
{
Chardev *chr = CHARDEV(obj);
diff --git a/gdbstub.c b/gdbstub.c
index d6ab950..c8478de 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -2038,7 +2038,11 @@
sigaction(SIGINT, &act, NULL);
}
#endif
- chr = qemu_chr_new_noreplay("gdb", device);
+ /*
+ * FIXME: it's a bit weird to allow using a mux chardev here
+ * and implicitly setup a monitor. We may want to break this.
+ */
+ chr = qemu_chr_new_noreplay("gdb", device, true);
if (!chr)
return -1;
}
diff --git a/hw/char/xen_console.c b/hw/char/xen_console.c
index 8b4b4bf..44f7236 100644
--- a/hw/char/xen_console.c
+++ b/hw/char/xen_console.c
@@ -207,7 +207,11 @@
} else {
snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
qemu_chr_fe_init(&con->chr,
- qemu_chr_new(label, output), &error_abort);
+ /*
+ * FIXME: sure we want to support implicit
+ * muxed monitors here?
+ */
+ qemu_chr_new_mux_mon(label, output), &error_abort);
}
xenstore_store_pv_console_info(con->xendev.dev,
diff --git a/include/chardev/char.h b/include/chardev/char.h
index 3e4fe6d..7becd8c 100644
--- a/include/chardev/char.h
+++ b/include/chardev/char.h
@@ -105,14 +105,27 @@
* @filename: the URI
*
* Create a new character backend from a URI.
+ * Do not implicitly initialize a monitor if the chardev is muxed.
*
* Returns: a new character backend
*/
Chardev *qemu_chr_new(const char *label, const char *filename);
/**
- * qemu_chr_change:
- * @opts: the new backend options
+ * qemu_chr_new_mux_mon:
+ * @label: the name of the backend
+ * @filename: the URI
+ *
+ * Create a new character backend from a URI.
+ * Implicitly initialize a monitor if the chardev is muxed.
+ *
+ * Returns: a new character backend
+ */
+Chardev *qemu_chr_new_mux_mon(const char *label, const char *filename);
+
+/**
+* qemu_chr_change:
+* @opts: the new backend options
*
* Change an existing character backend
*/
@@ -129,6 +142,7 @@
* qemu_chr_new_noreplay:
* @label: the name of the backend
* @filename: the URI
+ * @permit_mux_mon: if chardev is muxed, initialize a monitor
*
* Create a new character backend from a URI.
* Character device communications are not written
@@ -136,7 +150,8 @@
*
* Returns: a new character backend
*/
-Chardev *qemu_chr_new_noreplay(const char *label, const char *filename);
+Chardev *qemu_chr_new_noreplay(const char *label, const char *filename,
+ bool permit_mux_mon);
/**
* qemu_chr_be_can_write:
@@ -194,7 +209,8 @@
ChardevFeature feature);
void qemu_chr_set_feature(Chardev *chr,
ChardevFeature feature);
-QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename);
+QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename,
+ bool permit_mux_mon);
int qemu_chr_write(Chardev *s, const uint8_t *buf, int len, bool write_all);
#define qemu_chr_write_all(s, buf, len) qemu_chr_write(s, buf, len, true)
int qemu_chr_wait_connected(Chardev *chr, Error **errp);
diff --git a/net/slirp.c b/net/slirp.c
index c93b64d..99884de 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -764,7 +764,11 @@
}
} else {
Error *err = NULL;
- Chardev *chr = qemu_chr_new(buf, p);
+ /*
+ * FIXME: sure we want to support implicit
+ * muxed monitors here?
+ */
+ Chardev *chr = qemu_chr_new_mux_mon(buf, p);
if (!chr) {
error_setg(errp, "Could not open guest forwarding device '%s'",
diff --git a/vl.c b/vl.c
index 0388852..a867c9c 100644
--- a/vl.c
+++ b/vl.c
@@ -2310,7 +2310,7 @@
} else {
snprintf(label, sizeof(label), "compat_monitor%d",
monitor_device_index);
- opts = qemu_chr_parse_compat(label, optarg);
+ opts = qemu_chr_parse_compat(label, optarg, true);
if (!opts) {
error_report("parse error: %s", optarg);
exit(1);
@@ -2382,7 +2382,7 @@
snprintf(label, sizeof(label), "serial%d", index);
serial_hds = g_renew(Chardev *, serial_hds, index + 1);
- serial_hds[index] = qemu_chr_new(label, devname);
+ serial_hds[index] = qemu_chr_new_mux_mon(label, devname);
if (!serial_hds[index]) {
error_report("could not connect serial device"
" to character backend '%s'", devname);
@@ -2418,7 +2418,7 @@
exit(1);
}
snprintf(label, sizeof(label), "parallel%d", index);
- parallel_hds[index] = qemu_chr_new(label, devname);
+ parallel_hds[index] = qemu_chr_new_mux_mon(label, devname);
if (!parallel_hds[index]) {
error_report("could not connect parallel device"
" to character backend '%s'", devname);
@@ -2449,7 +2449,7 @@
qemu_opt_set(dev_opts, "driver", "virtconsole", &error_abort);
snprintf(label, sizeof(label), "virtcon%d", index);
- virtcon_hds[index] = qemu_chr_new(label, devname);
+ virtcon_hds[index] = qemu_chr_new_mux_mon(label, devname);
if (!virtcon_hds[index]) {
error_report("could not connect virtio console"
" to character backend '%s'", devname);
@@ -2465,7 +2465,7 @@
{
QemuOpts *opts;
- if (!qemu_chr_new("debugcon", devname)) {
+ if (!qemu_chr_new_mux_mon("debugcon", devname)) {
exit(1);
}
opts = qemu_opts_create(qemu_find_opts("device"), "debugcon", 1, NULL);
