[Qemu-devel] [PATCH V2] char: restore stdio echo on resume from suspend.

[Qemu-devel] [PATCH V2] char: restore stdio echo on resume from suspend.

[Gal Hammer]

The monitor's auto-completion feature stopped working when stdio is used
as an input and qemu was resumed after it was suspended (using ctrl-z).

Signed-off-by: Gal Hammer <ghammer@redhat.com>
---
V2 - restore old echo state rather than alway disable it.
   - don't check signal identifier in the handler function.
   - use sigaction() and not signal().
---
 qemu-char.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/qemu-char.c b/qemu-char.c
index ef84b53..5430b87 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -1112,6 +1112,9 @@ static struct termios oldtty;
 static int old_fd0_flags;
 static bool stdio_in_use;
 static bool stdio_allow_signal;
+static bool stdio_echo_state;
+
+static void qemu_chr_set_echo_stdio(CharDriverState *chr, bool echo);
 
 static void term_exit(void)
 {
@@ -1119,10 +1122,17 @@ static void term_exit(void)
     fcntl(0, F_SETFL, old_fd0_flags);
 }
 
+static void term_stdio_handler(int sig)
+{
+    /* restore echo after resume from suspend. */
+    qemu_chr_set_echo_stdio(NULL, stdio_echo_state);
+}
+
 static void qemu_chr_set_echo_stdio(CharDriverState *chr, bool echo)
 {
     struct termios tty;
 
+    stdio_echo_state = echo;
     tty = oldtty;
     if (!echo) {
         tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
@@ -1149,6 +1159,7 @@ static void qemu_chr_close_stdio(struct CharDriverState *chr)
 static CharDriverState *qemu_chr_open_stdio(ChardevStdio *opts)
 {
     CharDriverState *chr;
+    struct sigaction act;
 
     if (is_daemonized()) {
         error_report("cannot use stdio with -daemonize");
@@ -1166,6 +1177,10 @@ static CharDriverState *qemu_chr_open_stdio(ChardevStdio *opts)
     qemu_set_nonblock(0);
     atexit(term_exit);
 
+    memset(&act, 0, sizeof(act));
+    act.sa_handler = term_stdio_handler;
+    sigaction(SIGCONT, &act, NULL);
+
     chr = qemu_chr_open_fd(0, 1);
     chr->chr_close = qemu_chr_close_stdio;
     chr->chr_set_echo = qemu_chr_set_echo_stdio;
-- 
2.1.0

Re: [Qemu-devel] [PATCH V2] char: restore stdio echo on resume from suspend.

[Paolo Bonzini]

On 07/01/2015 09:38, Gal Hammer wrote:
> The monitor's auto-completion feature stopped working when stdio is used
> as an input and qemu was resumed after it was suspended (using ctrl-z).
> 
> Signed-off-by: Gal Hammer <ghammer@redhat.com>

Looks good, thanks Peter for reviewing v1.

Paolo

> ---
> V2 - restore old echo state rather than alway disable it.
>    - don't check signal identifier in the handler function.
>    - use sigaction() and not signal().
> ---
>  qemu-char.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/qemu-char.c b/qemu-char.c
> index ef84b53..5430b87 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -1112,6 +1112,9 @@ static struct termios oldtty;
>  static int old_fd0_flags;
>  static bool stdio_in_use;
>  static bool stdio_allow_signal;
> +static bool stdio_echo_state;
> +
> +static void qemu_chr_set_echo_stdio(CharDriverState *chr, bool echo);
>  
>  static void term_exit(void)
>  {
> @@ -1119,10 +1122,17 @@ static void term_exit(void)
>      fcntl(0, F_SETFL, old_fd0_flags);
>  }
>  
> +static void term_stdio_handler(int sig)
> +{
> +    /* restore echo after resume from suspend. */
> +    qemu_chr_set_echo_stdio(NULL, stdio_echo_state);
> +}
> +
>  static void qemu_chr_set_echo_stdio(CharDriverState *chr, bool echo)
>  {
>      struct termios tty;
>  
> +    stdio_echo_state = echo;
>      tty = oldtty;
>      if (!echo) {
>          tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
> @@ -1149,6 +1159,7 @@ static void qemu_chr_close_stdio(struct CharDriverState *chr)
>  static CharDriverState *qemu_chr_open_stdio(ChardevStdio *opts)
>  {
>      CharDriverState *chr;
> +    struct sigaction act;
>  
>      if (is_daemonized()) {
>          error_report("cannot use stdio with -daemonize");
> @@ -1166,6 +1177,10 @@ static CharDriverState *qemu_chr_open_stdio(ChardevStdio *opts)
>      qemu_set_nonblock(0);
>      atexit(term_exit);
>  
> +    memset(&act, 0, sizeof(act));
> +    act.sa_handler = term_stdio_handler;
> +    sigaction(SIGCONT, &act, NULL);
> +
>      chr = qemu_chr_open_fd(0, 1);
>      chr->chr_close = qemu_chr_close_stdio;
>      chr->chr_set_echo = qemu_chr_set_echo_stdio;
>