[Xen-devel] [PATCH 1/2] tools/console: reset tty when xenconsole fails

[Ian Jackson <ian.jackson@xxxxxxxxxxxxx>]

If xenconsole (the client program) fails, it calls err.  This would
previously neglect to reset the user's terminal to sanity.  Use atexit
to do so.

This routinely happens in Xen 4.4 RC5 with pygrub because something
writes the value "" to the tty xenstore key when using xenconsole.
The cause of this is not yet known, but after this patch it just
results in a harmless error message.

Reported-by: M A Young <m.a.young@xxxxxxxxxxxx>
Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CC: M A Young <m.a.young@xxxxxxxxxxxx>
CC: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
---
 tools/console/client/main.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tools/console/client/main.c b/tools/console/client/main.c
index eb6a1a9..62159f6 100644
--- a/tools/console/client/main.c
+++ b/tools/console/client/main.c
@@ -257,6 +257,13 @@ typedef enum {
        CONSOLE_SERIAL,
 } console_type;
 
+static struct termios stdin_old_attr;
+
+static void restore_term_stdin(void)
+{
+       restore_term(STDIN_FILENO, &stdin_old_attr);
+}
+
 int main(int argc, char **argv)
 {
        struct termios attr;
@@ -383,9 +390,9 @@ int main(int argc, char **argv)
        }
 
        init_term(spty, &attr);
-       init_term(STDIN_FILENO, &attr);
+       init_term(STDIN_FILENO, &stdin_old_attr);
+        atexit(restore_term_stdin); /* if this fails, oh dear */
        console_loop(spty, xs, path);
-       restore_term(STDIN_FILENO, &attr);
 
        free(path);
        free(dom_path);
-- 
1.7.10.4


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