From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:58436) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TliTH-0004hS-WD for qemu-devel@nongnu.org; Thu, 20 Dec 2012 10:55:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TliTF-0004I9-JO for qemu-devel@nongnu.org; Thu, 20 Dec 2012 10:55:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36247) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TliTF-0004Ht-9c for qemu-devel@nongnu.org; Thu, 20 Dec 2012 10:55:41 -0500 From: Markus Armbruster References: <1356014948-13450-1-git-send-email-lilei@linux.vnet.ibm.com> Date: Thu, 20 Dec 2012 16:19:39 +0100 In-Reply-To: <1356014948-13450-1-git-send-email-lilei@linux.vnet.ibm.com> (Lei Li's message of "Thu, 20 Dec 2012 22:49:08 +0800") Message-ID: <87bodohhtg.fsf@blackfin.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH] qemu-char: inherit ptys and imporve output from -serial pty List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Lei Li Cc: qemu-devel@nongnu.org Lei Li writes: > When controlling a qemu instance from another program, it's > hard to know which serial port or monitor device is redirected > to which pty. With more than one device using "pty" a lot of > guesswork is involved. > > $ ./x86_64-softmmu/qemu-system-x86_64 -serial pty -serial pty -monitor pty > char device redirected to /dev/pts/5 > char device redirected to /dev/pts/6 > char device redirected to /dev/pts/7 > > Although we can find out what everything else is connected to > by the "info chardev" with "-monitor stdio" in the command line, > It'd be very useful to be able to have qemu inherit pseudo-tty > file descriptors so they could just be specified on the command > line like: > > $ ./x86_64-softmmu/qemu-system-x86_64 -serial pty -serial pty -monitor pty > char device compat_monitor0 redirected to /dev/pts/5 > char device serial0 redirected to /dev/pts/6 > char device serial1 redirected to /dev/pts/7 > > Referred link: https://bugs.launchpad.net/qemu/+bug/938552 > > Reported-by: Craig Ringer > Signed-off-by: Lei Li > --- > qemu-char.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/qemu-char.c b/qemu-char.c > index 242b799..2b0f5f4 100644 > --- a/qemu-char.c > +++ b/qemu-char.c > @@ -981,6 +981,7 @@ static CharDriverState *qemu_chr_open_pty(QemuOpts *opts) > CharDriverState *chr; > PtyCharDriver *s; > struct termios tty; > + char *label; > int master_fd, slave_fd, len; > #if defined(__OpenBSD__) || defined(__DragonFly__) > char pty_name[PATH_MAX]; > @@ -1006,7 +1007,8 @@ static CharDriverState *qemu_chr_open_pty(QemuOpts *opts) > chr->filename = g_malloc(len); > snprintf(chr->filename, len, "pty:%s", q_ptsname(master_fd)); > qemu_opt_set(opts, "path", q_ptsname(master_fd)); > - fprintf(stderr, "char device redirected to %s\n", q_ptsname(master_fd)); > + label = g_strdup(qemu_opts_id(opts)); > + fprintf(stderr, "char device %s redirected to %s\n", label, q_ptsname(master_fd)); > > s = g_malloc0(sizeof(PtyCharDriver)); > chr->opaque = s; qemu_opts_id() may return null. g_strdup() then also returns null. Printing null with %s crashes on some systems. You leak label. Best fixed by not allocating in the first place. Try this: label = qemu_opts_id(opts) fprintf(stderr, "char device%S%s redirected to %s\n", label ? " " : "", label ?: , "", q_ptsname(master_fd)); Don't forget to imporve your subject :)