Commit 48c043d0 authored Apr 02, 2013 by Luiz Capitulino

hmp: human-monitor-command: stop using the Memory chardev driver



The Memory chardev driver was added because, as the Monitor's output
buffer was static, we needed a way to accumulate the output of an
HMP commmand when ran by human-monitor-command.

However, the Monitor's output buffer is now dynamic, so it's possible
for the human-monitor-command to use it instead of the Memory chardev
driver.

This commit does that change, but there are two important
observations about it:

 1. We need a way to signal to the Monitor that it shouldn't call
    chardev functions when flushing its output. This is done
    by adding a new flag to the Monitor object called skip_flush
	(which is set to true by qmp_human_monitor_command())

 2. The current code has buffered semantics: QMP clients will
    only see a command's output if it flushes its output with
	a new-line character. This commit changes this to unbuffered,
	which means that QMP clients will see a command's output
	whenever the command prints anything.

	I don't think this will matter in practice though, as I believe
	all HMP commands print the new-line character anyway.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

parent e1f2641b

monitor.c

+8 −9

Original line number	Diff line number	Diff line
		@@ -188,6 +188,7 @@ struct Monitor {
		int reset_seen;
		int flags;
		int suspend_cnt;
		bool skip_flush;
		QString *outbuf;
		ReadLineState *rs;
		MonitorControl *mc;
		@@ -273,6 +274,10 @@ void monitor_flush(Monitor *mon)
		size_t len;
		const char *buf;

		if (mon->skip_flush) {
		return;
		}

		buf = qstring_get_str(mon->outbuf);
		len = qstring_get_length(mon->outbuf);

		@@ -675,13 +680,10 @@ char qmp_human_monitor_command(const char command_line, bool has_cpu_index,
		{
		char *output = NULL;
		Monitor *old_mon, hmp;
		CharDriverState mchar;

		memset(&hmp, 0, sizeof(hmp));
		hmp.outbuf = qstring_new();

		qemu_chr_init_mem(&mchar);
		hmp.chr = &mchar;
		hmp.skip_flush = true;

		old_mon = cur_mon;
		cur_mon = &hmp;
		@@ -699,17 +701,14 @@ char qmp_human_monitor_command(const char command_line, bool has_cpu_index,
		handle_user_command(&hmp, command_line);
		cur_mon = old_mon;

		if (qemu_chr_mem_osize(hmp.chr) > 0) {
		QString *str = qemu_chr_mem_to_qs(hmp.chr);
		output = g_strdup(qstring_get_str(str));
		QDECREF(str);
		if (qstring_get_length(hmp.outbuf) > 0) {
		output = g_strdup(qstring_get_str(hmp.outbuf));
		} else {
		output = g_strdup("");
		}

		out:
		QDECREF(hmp.outbuf);
		qemu_chr_close_mem(hmp.chr);
		return output;
		}