monitor: Use getter/setter functions for cur_mon

cur_mon really needs to be coroutine-local as soon as we move monitor
command handlers to coroutines and let them yield. As a first step, just
remove all direct accesses to cur_mon so that we can implement this in
the getter function later.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20201005155855.256490-4-kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

audio/wavcapture.c

@@ -1,5 +1,5 @@
 #include "qemu/osdep.h"
-#include "monitor/monitor.h"
+#include "qemu/qemu-print.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "audio.h"
@@ -94,9 +94,9 @@ static void wav_capture_info (void *opaque)
     WAVState *wav = opaque;
     char *path = wav->path;
 
-    monitor_printf (cur_mon, "Capturing audio(%d,%d,%d) to %s: %d bytes\n",
-                    wav->freq, wav->bits, wav->nchannels,
-                    path ? path : "<not available>", wav->bytes);
+    qemu_printf("Capturing audio(%d,%d,%d) to %s: %d bytes\n",
+                wav->freq, wav->bits, wav->nchannels,
+                path ? path : "<not available>", wav->bytes);
 }
 
 static struct capture_ops wav_capture_ops = {

dump/dump.c

@@ -1986,7 +1986,7 @@ void qmp_dump_guest_memory(bool paging, const char *file,
 
 #if !defined(WIN32)
     if (strstart(file, "fd:", &p)) {
-        fd = monitor_get_fd(cur_mon, p, errp);
+        fd = monitor_get_fd(monitor_cur(), p, errp);
         if (fd == -1) {
             return;
         }

hw/scsi/vhost-scsi.c

@@ -177,7 +177,7 @@ static void vhost_scsi_realize(DeviceState *dev, Error **errp)
     }
 
     if (vs->conf.vhostfd) {
-        vhostfd = monitor_fd_param(cur_mon, vs->conf.vhostfd, errp);
+        vhostfd = monitor_fd_param(monitor_cur(), vs->conf.vhostfd, errp);
         if (vhostfd == -1) {
             error_prepend(errp, "vhost-scsi: unable to parse vhostfd: ");
             return;

hw/virtio/vhost-vsock.c

@@ -143,7 +143,7 @@ static void vhost_vsock_device_realize(DeviceState *dev, Error **errp)
     }
 
     if (vsock->conf.vhostfd) {
-        vhostfd = monitor_fd_param(cur_mon, vsock->conf.vhostfd, errp);
+        vhostfd = monitor_fd_param(monitor_cur(), vsock->conf.vhostfd, errp);
         if (vhostfd == -1) {
             error_prepend(errp, "vhost-vsock: unable to parse vhostfd: ");
             return;

include/monitor/monitor.h

@@ -5,14 +5,15 @@
 #include "qapi/qapi-types-misc.h"
 #include "qemu/readline.h"
 
-extern __thread Monitor *cur_mon;
 typedef struct MonitorHMP MonitorHMP;
 typedef struct MonitorOptions MonitorOptions;
 
 #define QMP_REQ_QUEUE_LEN_MAX 8
 
 extern QemuOptsList qemu_mon_opts;
 
+Monitor *monitor_cur(void);
+Monitor *monitor_set_cur(Monitor *mon);
 bool monitor_cur_is_qmp(void);
 
 void monitor_init_globals(void);

migration/fd.c

@@ -26,7 +26,7 @@
 void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
 {
     QIOChannel *ioc;
-    int fd = monitor_get_fd(cur_mon, fdname, errp);
+    int fd = monitor_get_fd(monitor_cur(), fdname, errp);
     if (fd == -1) {
         return;
     }
@@ -55,7 +55,7 @@ static gboolean fd_accept_incoming_migration(QIOChannel *ioc,
 void fd_start_incoming_migration(const char *fdname, Error **errp)
 {
     QIOChannel *ioc;
-    int fd = monitor_fd_param(cur_mon, fdname, errp);
+    int fd = monitor_fd_param(monitor_cur(), fdname, errp);
     if (fd == -1) {
         return;
     }

monitor/hmp.c

@@ -1300,26 +1300,25 @@ static void monitor_find_completion(void *opaque,
 
 static void monitor_read(void *opaque, const uint8_t *buf, int size)
 {
-    MonitorHMP *mon;
-    Monitor *old_mon = cur_mon;
+    MonitorHMP *mon = container_of(opaque, MonitorHMP, common);
+    Monitor *old_mon;
     int i;
 
-    cur_mon = opaque;
-    mon = container_of(cur_mon, MonitorHMP, common);
+    old_mon = monitor_set_cur(&mon->common);
 
     if (mon->rs) {
         for (i = 0; i < size; i++) {
             readline_handle_byte(mon->rs, buf[i]);
         }
     } else {
         if (size == 0 || buf[size - 1] != 0) {
-            monitor_printf(cur_mon, "corrupted command\n");
+            monitor_printf(&mon->common, "corrupted command\n");
         } else {
             handle_hmp_command(mon, (char *)buf);
         }
     }
 
-    cur_mon = old_mon;
+    monitor_set_cur(old_mon);
 }
 
 static void monitor_event(void *opaque, QEMUChrEvent event)

monitor/misc.c

@@ -125,21 +125,20 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index,
 
     monitor_data_init(&hmp.common, false, true, false);
 
-    old_mon = cur_mon;
-    cur_mon = &hmp.common;
+    old_mon = monitor_set_cur(&hmp.common);
 
     if (has_cpu_index) {
         int ret = monitor_set_cpu(&hmp.common, cpu_index);
         if (ret < 0) {
-            cur_mon = old_mon;
+            monitor_set_cur(old_mon);
             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cpu-index",
                        "a CPU number");
             goto out;
         }
     }
 
     handle_hmp_command(&hmp, command_line);
-    cur_mon = old_mon;
+    monitor_set_cur(old_mon);
 
     WITH_QEMU_LOCK_GUARD(&hmp.common.mon_lock) {
         if (qstring_get_length(hmp.common.outbuf) > 0) {
@@ -297,7 +296,7 @@ static CPUState *mon_get_cpu_sync(Monitor *mon, bool synchronize)
 
 CPUState *mon_get_cpu(void)
 {
-    return mon_get_cpu_sync(cur_mon, true);
+    return mon_get_cpu_sync(monitor_cur(), true);
 }
 
 CPUArchState *mon_get_cpu_env(void)
@@ -1232,6 +1231,7 @@ static void hmp_acl_remove(Monitor *mon, const QDict *qdict)
 
 void qmp_getfd(const char *fdname, Error **errp)
 {
+    Monitor *cur_mon = monitor_cur();
     mon_fd_t *monfd;
     int fd, tmp_fd;
 
@@ -1270,6 +1270,7 @@ void qmp_getfd(const char *fdname, Error **errp)
 
 void qmp_closefd(const char *fdname, Error **errp)
 {
+    Monitor *cur_mon = monitor_cur();
     mon_fd_t *monfd;
     int tmp_fd;
 
@@ -1356,7 +1357,7 @@ AddfdInfo *qmp_add_fd(bool has_fdset_id, int64_t fdset_id, bool has_opaque,
                       const char *opaque, Error **errp)
 {
     int fd;
-    Monitor *mon = cur_mon;
+    Monitor *mon = monitor_cur();
     AddfdInfo *fdinfo;
 
     fd = qemu_chr_fe_get_msgfd(&mon->chr);

monitor/monitor.c

@@ -66,13 +66,31 @@ MonitorList mon_list;
 int mon_refcount;
 static bool monitor_destroyed;
 
-__thread Monitor *cur_mon;
+static __thread Monitor *cur_monitor;
+
+Monitor *monitor_cur(void)
+{
+    return cur_monitor;
+}
+
+/**
+ * Sets a new current monitor and returns the old one.
+ */
+Monitor *monitor_set_cur(Monitor *mon)
+{
+    Monitor *old_monitor = cur_monitor;
+
+    cur_monitor = mon;
+    return old_monitor;
+}
 
 /**
  * Is the current monitor, if any, a QMP monitor?
  */
 bool monitor_cur_is_qmp(void)
 {
+    Monitor *cur_mon = monitor_cur();
+
     return cur_mon && monitor_is_qmp(cur_mon);
 }
 
@@ -209,6 +227,8 @@ int monitor_printf(Monitor *mon, const char *fmt, ...)
  */
 int error_vprintf(const char *fmt, va_list ap)
 {
+    Monitor *cur_mon = monitor_cur();
+
     if (cur_mon && !monitor_cur_is_qmp()) {
         return monitor_vprintf(cur_mon, fmt, ap);
     }
@@ -217,6 +237,8 @@ int error_vprintf(const char *fmt, va_list ap)
 
 int error_vprintf_unless_qmp(const char *fmt, va_list ap)
 {
+    Monitor *cur_mon = monitor_cur();
+
     if (!cur_mon) {
         return vfprintf(stderr, fmt, ap);
     }

monitor/qmp-cmds-control.c

@@ -69,6 +69,7 @@ static bool qmp_caps_accept(MonitorQMP *mon, QMPCapabilityList *list,
 void qmp_qmp_capabilities(bool has_enable, QMPCapabilityList *enable,
                           Error **errp)
 {
+    Monitor *cur_mon = monitor_cur();
     MonitorQMP *mon;
 
     assert(monitor_is_qmp(cur_mon));
@@ -119,6 +120,7 @@ static void query_commands_cb(const QmpCommand *cmd, void *opaque)
 CommandInfoList *qmp_query_commands(Error **errp)
 {
     CommandInfoList *list = NULL;
+    Monitor *cur_mon = monitor_cur();
     MonitorQMP *mon;
 
     assert(monitor_is_qmp(cur_mon));

monitor/qmp-cmds.c

@@ -328,7 +328,7 @@ void qmp_add_client(const char *protocol, const char *fdname,
     Chardev *s;
     int fd;
 
-    fd = monitor_get_fd(cur_mon, fdname, errp);
+    fd = monitor_get_fd(monitor_cur(), fdname, errp);
     if (fd < 0) {
         return;
     }

monitor/qmp.c

@@ -139,12 +139,9 @@ static void monitor_qmp_dispatch(MonitorQMP *mon, QObject *req)
     QDict *rsp;
     QDict *error;
 
-    old_mon = cur_mon;
-    cur_mon = &mon->common;
-
+    old_mon = monitor_set_cur(&mon->common);
     rsp = qmp_dispatch(mon->commands, req, qmp_oob_enabled(mon));
-
-    cur_mon = old_mon;
+    monitor_set_cur(old_mon);
 
     if (mon->commands == &qmp_cap_negotiation_commands) {
         error = qdict_get_qdict(rsp, "error");

net/socket.c

@@ -727,7 +727,7 @@ int net_init_socket(const Netdev *netdev, const char *name,
     if (sock->has_fd) {
         int fd, ret;
 
-        fd = monitor_fd_param(cur_mon, sock->fd, errp);
+        fd = monitor_fd_param(monitor_cur(), sock->fd, errp);
         if (fd == -1) {
             return -1;
         }

net/tap.c

@@ -700,7 +700,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
         if (vhostfdname) {
             int ret;
 
-            vhostfd = monitor_fd_param(cur_mon, vhostfdname, &err);
+            vhostfd = monitor_fd_param(monitor_cur(), vhostfdname, &err);
             if (vhostfd == -1) {
                 if (tap->has_vhostforce && tap->vhostforce) {
                     error_propagate(errp, err);
@@ -808,7 +808,7 @@ int net_init_tap(const Netdev *netdev, const char *name,
             return -1;
         }
 
-        fd = monitor_fd_param(cur_mon, tap->fd, errp);
+        fd = monitor_fd_param(monitor_cur(), tap->fd, errp);
         if (fd == -1) {
             return -1;
         }
@@ -862,7 +862,7 @@ int net_init_tap(const Netdev *netdev, const char *name,
         }
 
         for (i = 0; i < nfds; i++) {
-            fd = monitor_fd_param(cur_mon, fds[i], errp);
+            fd = monitor_fd_param(monitor_cur(), fds[i], errp);
             if (fd == -1) {
                 ret = -1;
                 goto free_fail;

softmmu/cpus.c

@@ -793,6 +793,6 @@ void qmp_pmemsave(int64_t addr, int64_t size, const char *filename,
 
 void qmp_inject_nmi(Error **errp)
 {
-    nmi_monitor_handle(monitor_get_cpu_index(cur_mon), errp);
+    nmi_monitor_handle(monitor_get_cpu_index(monitor_cur()), errp);
 }
 

stubs/monitor-core.c

@@ -3,7 +3,10 @@
 #include "qemu-common.h"
 #include "qapi/qapi-emit-events.h"
 
-__thread Monitor *cur_mon;
+Monitor *monitor_cur(void)
+{
+    return NULL;
+}
 
 void monitor_init_qmp(Chardev *chr, bool pretty, Error **errp)
 {

tests/test-util-sockets.c

@@ -52,6 +52,7 @@ static void test_fd_is_socket_good(void)
 
 static int mon_fd = -1;
 static const char *mon_fdname;
+__thread Monitor *cur_mon;
 
 int monitor_get_fd(Monitor *mon, const char *fdname, Error **errp)
 {
@@ -65,15 +66,14 @@ int monitor_get_fd(Monitor *mon, const char *fdname, Error **errp)
 }
 
 /*
- * Syms of stubs in libqemuutil.a are discarded at .o file granularity.
- * To replace monitor_get_fd() we must ensure everything in
- * stubs/monitor.c is defined, to make sure monitor.o is discarded
+ * Syms of stubs in libqemuutil.a are discarded at .o file
+ * granularity.  To replace monitor_get_fd() and monitor_cur(), we
+ * must ensure that we also replace any other symbol that is used in
+ * the binary and would be taken from the same stub object file,
  * otherwise we get duplicate syms at link time.
  */
-__thread Monitor *cur_mon;
+Monitor *monitor_cur(void) { return 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, Error **errp) {}
 
 #ifndef _WIN32
 static void test_socket_fd_pass_name_good(void)

trace/control.c

@@ -176,7 +176,7 @@ void trace_enable_events(const char *line_buf)
 {
     if (is_help_option(line_buf)) {
         trace_list_events();
-        if (cur_mon == NULL) {
+        if (monitor_cur() == NULL) {
             exit(0);
         }
     } else {

util/qemu-error.c

@@ -171,7 +171,7 @@ static void print_loc(void)
     int i;
     const char *const *argp;
 
-    if (!cur_mon && progname) {
+    if (!monitor_cur() && progname) {
         fprintf(stderr, "%s:", progname);
         sep = " ";
     }
@@ -208,15 +208,15 @@ static void vreport(report_type type, const char *fmt, va_list ap)
     GTimeVal tv;
     gchar *timestr;
 
-    if (error_with_timestamp && !cur_mon) {
+    if (error_with_timestamp && !monitor_cur()) {
         g_get_current_time(&tv);
         timestr = g_time_val_to_iso8601(&tv);
         error_printf("%s ", timestr);
         g_free(timestr);
     }
 
     /* Only prepend guest name if -msg guest-name and -name guest=... are set */
-    if (error_with_guestname && error_guest_name && !cur_mon) {
+    if (error_with_guestname && error_guest_name && !monitor_cur()) {
         error_printf("%s ", error_guest_name);
     }