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[Qemu-devel] [PATCH v2] qemu-char: fix terminal crash when using "-monit
From: |
john.liuli |
Subject: |
[Qemu-devel] [PATCH v2] qemu-char: fix terminal crash when using "-monitor stdio -nographic" |
Date: |
Tue, 9 Sep 2014 19:19:48 +0800 |
From: Li Liu <address@hidden>
Eeay to reproduce, just try "qemu -monitor stdio -nographic"
and type "quit", then the terminal will be crashed.
There are two pathes try to call tcgetattr of stdio in vl.c:
1) Monitor_parse(optarg, "readline");
.....
qemu_opts_foreach(qemu_find_opts("chardev"),
chardev_init_func, NULL, 1) != 0)
2) if (default_serial)
add_device_config(DEV_SERIAL, "stdio");
....
if (foreach_device_config(DEV_SERIAL, serial_parse) < 0)
Both of them will trigger qemu_chr_open_stdio which will disable
ECHO attributes. First one has updated the attributes of stdio
by calling qemu_chr_fe_set_echo(chr, false). And the tty
attributes has been saved in oldtty. Then the second path will
redo such actions, and the oldtty is overlapped. So till "quit",
term_exit can't recove the correct attributes.
Signed-off-by: Li Liu <address@hidden>
---
changes v1 -> v2:
1) as Markus Armbruster and Gerd Hoffmann suggested :
Multiple character devices can't use the same terminal.
So catch and reject the attempt if stdio is opened already.
---
qemu-char.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/qemu-char.c b/qemu-char.c
index d4f327a..f8f0c48 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -1017,6 +1017,7 @@ static CharDriverState *qemu_chr_open_pipe(ChardevHostdev
*opts)
/* init terminal so that we can grab keys */
static struct termios oldtty;
static int old_fd0_flags;
+static bool stdio_is_ready;
static bool stdio_allow_signal;
static void term_exit(void)
@@ -1060,8 +1061,15 @@ static CharDriverState *qemu_chr_open_stdio(ChardevStdio
*opts)
error_report("cannot use stdio with -daemonize");
return NULL;
}
+
+ if (stdio_is_ready) {
+ error_report("cannot use stdio by multiple character devices");
+ exit(1);
+ }
+
+ stdio_is_ready = true;
old_fd0_flags = fcntl(0, F_GETFL);
- tcgetattr (0, &oldtty);
+ tcgetattr(0, &oldtty);
qemu_set_nonblock(0);
atexit(term_exit);
--
1.7.9.5
- [Qemu-devel] [PATCH v2] qemu-char: fix terminal crash when using "-monitor stdio -nographic",
john.liuli <=