Commit 6cff3e85 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Luiz Capitulino
Browse files

monitor: protect outbuf and mux_out with mutex 



This lets the block layer emit QMP events from outside the I/O thread.

Reviewed-by: default avatarLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarLuiz Capitulino <lcapitulino@redhat.com>
parent 9005b2a7

monitor.c

+36 −9
Original line number Diff line number Diff line
@@ -191,13 +191,18 @@ typedef struct MonitorQAPIEventState { 


struct Monitor {

    CharDriverState *chr;

    int mux_out;

    int reset_seen;

    int flags;

    int suspend_cnt;

    bool skip_flush;



    QemuMutex out_lock;

    QString *outbuf;

    guint watch;

    guint out_watch;



    /* Read under either BQL or out_lock, written with BQL+out_lock.  */

    int mux_out;



    ReadLineState *rs;

    MonitorControl *mc;

    CPUState *mon_cpu;
@@ -270,17 +275,22 @@ int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func, 
    }

}



static void monitor_flush_locked(Monitor *mon);



static gboolean monitor_unblocked(GIOChannel *chan, GIOCondition cond,

                                  void *opaque)

{

    Monitor *mon = opaque;



    mon->watch = 0;

    monitor_flush(mon);

    qemu_mutex_lock(&mon->out_lock);

    mon->out_watch = 0;

    monitor_flush_locked(mon);

    qemu_mutex_unlock(&mon->out_lock);

    return FALSE;

}



void monitor_flush(Monitor *mon)

/* Called with mon->out_lock held.  */

static void monitor_flush_locked(Monitor *mon)

{

    int rc;

    size_t len;
@@ -307,18 +317,26 @@ void monitor_flush(Monitor *mon) 
            QDECREF(mon->outbuf);

            mon->outbuf = tmp;

        }

        if (mon->watch == 0) {

            mon->watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT,

        if (mon->out_watch == 0) {

            mon->out_watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT,

                                                   monitor_unblocked, mon);

        }

    }

}



void monitor_flush(Monitor *mon)

{

    qemu_mutex_lock(&mon->out_lock);

    monitor_flush_locked(mon);

    qemu_mutex_unlock(&mon->out_lock);

}



/* flush at every end of line */

static void monitor_puts(Monitor *mon, const char *str)

{

    char c;



    qemu_mutex_lock(&mon->out_lock);

    for(;;) {

        c = *str++;

        if (c == '\0')
@@ -328,9 +346,10 @@ static void monitor_puts(Monitor *mon, const char *str) 
        }

        qstring_append_chr(mon->outbuf, c);

        if (c == '\n') {

            monitor_flush(mon);

            monitor_flush_locked(mon);

        }

    }

    qemu_mutex_unlock(&mon->out_lock);

}



void monitor_vprintf(Monitor *mon, const char *fmt, va_list ap)
@@ -581,6 +600,7 @@ static void handle_user_command(Monitor *mon, const char *cmdline); 
static void monitor_data_init(Monitor *mon)

{

    memset(mon, 0, sizeof(Monitor));

    qemu_mutex_init(&mon->out_lock);

    mon->outbuf = qstring_new();

    /* Use *mon_cmds by default. */

    mon->cmd_table = mon_cmds;
@@ -589,6 +609,7 @@ static void monitor_data_init(Monitor *mon) 
static void monitor_data_destroy(Monitor *mon)

{

    QDECREF(mon->outbuf);

    qemu_mutex_destroy(&mon->out_lock);

}



char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index,
@@ -616,11 +637,13 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index, 
    handle_user_command(&hmp, command_line);

    cur_mon = old_mon;



    qemu_mutex_lock(&hmp.out_lock);

    if (qstring_get_length(hmp.outbuf) > 0) {

        output = g_strdup(qstring_get_str(hmp.outbuf));

    } else {

        output = g_strdup("");

    }

    qemu_mutex_unlock(&hmp.out_lock);



out:

    monitor_data_destroy(&hmp);
@@ -5180,7 +5203,9 @@ static void monitor_event(void *opaque, int event) 


    switch (event) {

    case CHR_EVENT_MUX_IN:

        qemu_mutex_lock(&mon->out_lock);

        mon->mux_out = 0;

        qemu_mutex_unlock(&mon->out_lock);

        if (mon->reset_seen) {

            readline_restart(mon->rs);

            monitor_resume(mon);
@@ -5200,7 +5225,9 @@ static void monitor_event(void *opaque, int event) 
        } else {

            mon->suspend_cnt++;

        }

        qemu_mutex_lock(&mon->out_lock);

        mon->mux_out = 1;

        qemu_mutex_unlock(&mon->out_lock);

        break;



    case CHR_EVENT_OPENED: