Patchwork [v2] create qemu_openpty_raw() helper function and move it to a separate file

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Submitter Michael Tokarev
Date June 5, 2013, 3:25 p.m.
Message ID <1370445949-6666-1-git-send-email-mjt@msgid.tls.msk.ru>
Download mbox | patch
Permalink /patch/249111/
State New
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Comments

Michael Tokarev - June 5, 2013, 3:25 p.m.
In two places qemu uses openpty() which is very system-dependent,
and in both places the pty is switched to raw mode as well.
Make a wrapper function which does both steps, and move all the
system-dependent complexity into a separate file, together
with static/local implementations of openpty() and cfmakeraw()
from qemu-char.c.

It is in a separate file, not part of oslib-posix.c, because
openpty() often resides in -lutil which is not linked to
every program qemu builds.

This change removes #including of <pty.h>, <termios.h>
and other rather specific system headers out of qemu-common.h,
which isn't a place for such specific headers really.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
Changes since v1:

- added a forgotten #include <termios.h> for *BSD,
  which was recently added into qemu-common.h by
  Brad Smith, and which I intended to use in
  qemu-openpty.c too, but somehow forgot.

And one extra comment.  I especially took existing
code and used it almost unmodified, to have one
code moving change, with all other possible
improvements/cleanups to follow later.

 include/qemu-common.h |   15 +-----
 qemu-char.c           |   77 ++--------------------------
 ui/gtk.c              |   12 ++---
 util/Makefile.objs    |    2 +-
 util/qemu-openpty.c   |  135 +++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 146 insertions(+), 95 deletions(-)
 create mode 100644 util/qemu-openpty.c
Brad - June 7, 2013, 3:05 p.m.
On 05/06/13 11:25 AM, Michael Tokarev wrote:
> In two places qemu uses openpty() which is very system-dependent,
> and in both places the pty is switched to raw mode as well.
> Make a wrapper function which does both steps, and move all the
> system-dependent complexity into a separate file, together
> with static/local implementations of openpty() and cfmakeraw()
> from qemu-char.c.
>
> It is in a separate file, not part of oslib-posix.c, because
> openpty() often resides in -lutil which is not linked to
> every program qemu builds.
>
> This change removes #including of <pty.h>, <termios.h>
> and other rather specific system headers out of qemu-common.h,
> which isn't a place for such specific headers really.
>
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
> Changes since v1:
>
> - added a forgotten #include <termios.h> for *BSD,
>    which was recently added into qemu-common.h by
>    Brad Smith, and which I intended to use in
>    qemu-openpty.c too, but somehow forgot.
>
> And one extra comment.  I especially took existing
> code and used it almost unmodified, to have one
> code moving change, with all other possible
> improvements/cleanups to follow later.

This builds Ok on OpenBSD.
Michael Tokarev - June 11, 2013, 12:57 p.m.
05.06.2013 19:25, Michael Tokarev wrote:
> In two places qemu uses openpty() which is very system-dependent,
> and in both places the pty is switched to raw mode as well.
> Make a wrapper function which does both steps, and move all the
> system-dependent complexity into a separate file, together
> with static/local implementations of openpty() and cfmakeraw()
> from qemu-char.c.
> 
> It is in a separate file, not part of oslib-posix.c, because
> openpty() often resides in -lutil which is not linked to
> every program qemu builds.
> 
> This change removes #including of <pty.h>, <termios.h>
> and other rather specific system headers out of qemu-common.h,
> which isn't a place for such specific headers really.

So guys/gals what do you think of this?  It builds on OpenBSD
and FreeBSD as verified by Brad Smith and me, and it builds on
Linux.  And it is trivial enough for qemu-trivial (no actual
code changes, just some refactoring and moving).  Can we
let it in?

There's no one else who signed this off ;)

> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

Thanks,

/mjt
Brad - June 12, 2013, 11:49 p.m.
On 11/06/13 8:57 AM, Michael Tokarev wrote:
> 05.06.2013 19:25, Michael Tokarev wrote:
>> In two places qemu uses openpty() which is very system-dependent,
>> and in both places the pty is switched to raw mode as well.
>> Make a wrapper function which does both steps, and move all the
>> system-dependent complexity into a separate file, together
>> with static/local implementations of openpty() and cfmakeraw()
>> from qemu-char.c.
>>
>> It is in a separate file, not part of oslib-posix.c, because
>> openpty() often resides in -lutil which is not linked to
>> every program qemu builds.
>>
>> This change removes #including of <pty.h>, <termios.h>
>> and other rather specific system headers out of qemu-common.h,
>> which isn't a place for such specific headers really.
>
> So guys/gals what do you think of this?  It builds on OpenBSD
> and FreeBSD as verified by Brad Smith and me, and it builds on
> Linux.  And it is trivial enough for qemu-trivial (no actual
> code changes, just some refactoring and moving).  Can we
> let it in?
>
> There's no one else who signed this off ;)
>
>> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

It would be nice to get this in to fix the build with Solaris (that's
if there is nothing else I am not aware of which breaks the build there) 
and to get this in the queue for 1.5 too.
Michael Tokarev - June 13, 2013, 6:57 a.m.
13.06.2013 03:49, Brad Smith wrote:
[]
> It would be nice to get this in to fix the build with Solaris (that's
> if there is nothing else I am not aware of which breaks the build there) and to get this in the queue for 1.5 too.

I'll test it on solaris 10 x86 tonight.  Started downloading an install dvd.
(FWIW, as we don't support solaris as a first-class host system, this can
just as well be ignored; however I'm certain it will not break on there).

Thanks,

/mjt
Andreas Färber - June 13, 2013, 8:50 a.m.
Am 05.06.2013 17:25, schrieb Michael Tokarev:
> In two places qemu uses openpty() which is very system-dependent,
> and in both places the pty is switched to raw mode as well.
> Make a wrapper function which does both steps, and move all the
> system-dependent complexity into a separate file, together
> with static/local implementations of openpty() and cfmakeraw()
> from qemu-char.c.
> 
> It is in a separate file, not part of oslib-posix.c, because
> openpty() often resides in -lutil which is not linked to
> every program qemu builds.
> 
> This change removes #including of <pty.h>, <termios.h>
> and other rather specific system headers out of qemu-common.h,
> which isn't a place for such specific headers really.
> 
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
> Changes since v1:
> 
> - added a forgotten #include <termios.h> for *BSD,
>   which was recently added into qemu-common.h by
>   Brad Smith, and which I intended to use in
>   qemu-openpty.c too, but somehow forgot.
> 
> And one extra comment.  I especially took existing
> code and used it almost unmodified, to have one
> code moving change, with all other possible
> improvements/cleanups to follow later.
> 
>  include/qemu-common.h |   15 +-----
>  qemu-char.c           |   77 ++--------------------------
>  ui/gtk.c              |   12 ++---
>  util/Makefile.objs    |    2 +-
>  util/qemu-openpty.c   |  135 +++++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 146 insertions(+), 95 deletions(-)
>  create mode 100644 util/qemu-openpty.c

Git complains about a trailing white line in the new file.

And unfortunately it doesn't build as-is:

  CC    util/qemu-openpty.o
/home/andreas/QEMU/qemu/util/qemu-openpty.c:54: warning: ‘struct
winsize’ declared inside parameter list
/home/andreas/QEMU/qemu/util/qemu-openpty.c:54: warning: its scope is
only this definition or declaration, which is probably not what you want
/home/andreas/QEMU/qemu/util/qemu-openpty.c:54: warning: ‘struct
termios’ declared inside parameter list
/home/andreas/QEMU/qemu/util/qemu-openpty.c: In function ‘openpty’:
/home/andreas/QEMU/qemu/util/qemu-openpty.c:75: warning: implicit
declaration of function ‘tcgetattr’
/home/andreas/QEMU/qemu/util/qemu-openpty.c:75: warning: nested extern
declaration of ‘tcgetattr’
/home/andreas/QEMU/qemu/util/qemu-openpty.c:83: error: ‘TIOCSWINSZ’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:83: error: (Each undeclared
identifier is reported only once
/home/andreas/QEMU/qemu/util/qemu-openpty.c:83: error: for each function
it appears in.)
/home/andreas/QEMU/qemu/util/qemu-openpty.c: At top level:
/home/andreas/QEMU/qemu/util/qemu-openpty.c:94: warning: ‘struct
termios’ declared inside parameter list
/home/andreas/QEMU/qemu/util/qemu-openpty.c: In function ‘cfmakeraw’:
/home/andreas/QEMU/qemu/util/qemu-openpty.c:96: error: dereferencing
pointer to incomplete type
/home/andreas/QEMU/qemu/util/qemu-openpty.c:97: error: ‘IGNBRK’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:97: error: ‘BRKINT’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:97: error: ‘PARMRK’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:97: error: ‘ISTRIP’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:97: error: ‘INLCR’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:97: error: ‘IGNCR’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:97: error: ‘ICRNL’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:97: error: ‘IXON’ undeclared
(first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:98: error: dereferencing
pointer to incomplete type
/home/andreas/QEMU/qemu/util/qemu-openpty.c:98: error: ‘OPOST’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:99: error: dereferencing
pointer to incomplete type
/home/andreas/QEMU/qemu/util/qemu-openpty.c:99: error: ‘ECHO’ undeclared
(first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:99: error: ‘ECHONL’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:99: error: ‘ICANON’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:99: error: ‘ISIG’ undeclared
(first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:99: error: ‘IEXTEN’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:100: error: dereferencing
pointer to incomplete type
/home/andreas/QEMU/qemu/util/qemu-openpty.c:100: error: ‘CSIZE’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:100: error: ‘PARENB’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:101: error: dereferencing
pointer to incomplete type
/home/andreas/QEMU/qemu/util/qemu-openpty.c:101: error: ‘CS8’ undeclared
(first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:103: error: dereferencing
pointer to incomplete type
/home/andreas/QEMU/qemu/util/qemu-openpty.c:103: error: ‘VMIN’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:104: error: dereferencing
pointer to incomplete type
/home/andreas/QEMU/qemu/util/qemu-openpty.c:104: error: ‘VTIME’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c: In function ‘qemu_openpty_raw’:
/home/andreas/QEMU/qemu/util/qemu-openpty.c:111: error: storage size of
‘tty’ isn’t known
/home/andreas/QEMU/qemu/util/qemu-openpty.c:127: warning: implicit
declaration of function ‘tcsetattr’
/home/andreas/QEMU/qemu/util/qemu-openpty.c:127: warning: nested extern
declaration of ‘tcsetattr’
/home/andreas/QEMU/qemu/util/qemu-openpty.c:127: error: ‘TCSAFLUSH’
undeclared (first use in this function)
/home/andreas/QEMU/qemu/util/qemu-openpty.c:111: warning: unused
variable ‘tty’
make: *** [util/qemu-openpty.o] Fehler 1

Unfortunately don't have time right now to investigate further.

Andreas

Patch

diff --git a/include/qemu-common.h b/include/qemu-common.h
index cb82ef3..3b1ca8e 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -42,19 +42,6 @@ 
 #include <signal.h>
 #include "glib-compat.h"
 
-#if defined(__GLIBC__)
-# include <pty.h>
-#elif defined CONFIG_BSD
-# include <termios.h>
-# if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
-#  include <libutil.h>
-# else
-#  include <util.h>
-# endif
-#elif defined CONFIG_SOLARIS
-# include <stropts.h>
-#endif
-
 #ifdef _WIN32
 #include "sysemu/os-win32.h"
 #endif
@@ -232,6 +219,8 @@  ssize_t qemu_recv_full(int fd, void *buf, size_t count, int flags)
 
 #ifndef _WIN32
 int qemu_pipe(int pipefd[2]);
+/* like openpty() but also makes it raw; return master fd */
+int qemu_openpty_raw(int *aslave, char *pty_name);
 #endif
 
 #ifdef _WIN32
diff --git a/qemu-char.c b/qemu-char.c
index d04b429..3759eff 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -980,63 +980,6 @@  static CharDriverState *qemu_chr_open_stdio(ChardevStdio *opts)
     return chr;
 }
 
-#ifdef __sun__
-/* Once Solaris has openpty(), this is going to be removed. */
-static int openpty(int *amaster, int *aslave, char *name,
-                   struct termios *termp, struct winsize *winp)
-{
-        const char *slave;
-        int mfd = -1, sfd = -1;
-
-        *amaster = *aslave = -1;
-
-        mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
-        if (mfd < 0)
-                goto err;
-
-        if (grantpt(mfd) == -1 || unlockpt(mfd) == -1)
-                goto err;
-
-        if ((slave = ptsname(mfd)) == NULL)
-                goto err;
-
-        if ((sfd = open(slave, O_RDONLY | O_NOCTTY)) == -1)
-                goto err;
-
-        if (ioctl(sfd, I_PUSH, "ptem") == -1 ||
-            (termp != NULL && tcgetattr(sfd, termp) < 0))
-                goto err;
-
-        if (amaster)
-                *amaster = mfd;
-        if (aslave)
-                *aslave = sfd;
-        if (winp)
-                ioctl(sfd, TIOCSWINSZ, winp);
-
-        return 0;
-
-err:
-        if (sfd != -1)
-                close(sfd);
-        close(mfd);
-        return -1;
-}
-
-static void cfmakeraw (struct termios *termios_p)
-{
-        termios_p->c_iflag &=
-                ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
-        termios_p->c_oflag &= ~OPOST;
-        termios_p->c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
-        termios_p->c_cflag &= ~(CSIZE|PARENB);
-        termios_p->c_cflag |= CS8;
-
-        termios_p->c_cc[VMIN] = 0;
-        termios_p->c_cc[VTIME] = 0;
-}
-#endif
-
 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
     || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \
     || defined(__GLIBC__)
@@ -1208,34 +1151,24 @@  static CharDriverState *qemu_chr_open_pty(const char *id,
 {
     CharDriverState *chr;
     PtyCharDriver *s;
-    struct termios tty;
     int master_fd, slave_fd;
-#if defined(__OpenBSD__) || defined(__DragonFly__)
     char pty_name[PATH_MAX];
-#define q_ptsname(x) pty_name
-#else
-    char *pty_name = NULL;
-#define q_ptsname(x) ptsname(x)
-#endif
 
-    if (openpty(&master_fd, &slave_fd, pty_name, NULL, NULL) < 0) {
+    master_fd = qemu_openpty_raw(&slave_fd, pty_name);
+    if (master_fd < 0) {
         return NULL;
     }
 
-    /* Set raw attributes on the pty. */
-    tcgetattr(slave_fd, &tty);
-    cfmakeraw(&tty);
-    tcsetattr(slave_fd, TCSAFLUSH, &tty);
     close(slave_fd);
 
     chr = g_malloc0(sizeof(CharDriverState));
 
-    chr->filename = g_strdup_printf("pty:%s", q_ptsname(master_fd));
-    ret->pty = g_strdup(q_ptsname(master_fd));
+    chr->filename = g_strdup_printf("pty:%s", pty_name);
+    ret->pty = g_strdup(pty_name);
     ret->has_pty = true;
 
     fprintf(stderr, "char device redirected to %s (label %s)\n",
-            q_ptsname(master_fd), id);
+            pty_name, id);
 
     s = g_malloc0(sizeof(PtyCharDriver));
     chr->opaque = s;
diff --git a/ui/gtk.c b/ui/gtk.c
index 52c3f95..3405df6 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -1156,8 +1156,7 @@  static GSList *gd_vc_init(GtkDisplayState *s, VirtualConsole *vc, int index, GSL
     GIOChannel *chan;
     GtkWidget *scrolled_window;
     GtkAdjustment *vadjustment;
-    int master_fd, slave_fd, ret;
-    struct termios tty;
+    int master_fd, slave_fd;
 
     snprintf(buffer, sizeof(buffer), "vc%d", index);
     snprintf(path, sizeof(path), "<QEMU>/View/VC%d", index);
@@ -1177,13 +1176,8 @@  static GSList *gd_vc_init(GtkDisplayState *s, VirtualConsole *vc, int index, GSL
 
     vc->terminal = vte_terminal_new();
 
-    ret = openpty(&master_fd, &slave_fd, NULL, NULL, NULL);
-    g_assert(ret != -1);
-
-    /* Set raw attributes on the pty. */
-    tcgetattr(slave_fd, &tty);
-    cfmakeraw(&tty);
-    tcsetattr(slave_fd, TCSAFLUSH, &tty);
+    master_fd = qemu_openpty_raw(&slave_fd, NULL);
+    g_assert(master_fd != -1);
 
 #if VTE_CHECK_VERSION(0, 26, 0)
     pty = vte_pty_new_foreign(master_fd, NULL);
diff --git a/util/Makefile.objs b/util/Makefile.objs
index 4a1bd4e..dc72ab0 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -1,6 +1,6 @@ 
 util-obj-y = osdep.o cutils.o unicode.o qemu-timer-common.o
 util-obj-$(CONFIG_WIN32) += oslib-win32.o qemu-thread-win32.o event_notifier-win32.o
-util-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o event_notifier-posix.o
+util-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o event_notifier-posix.o qemu-openpty.o
 util-obj-y += envlist.o path.o host-utils.o cache-utils.o module.o
 util-obj-y += bitmap.o bitops.o hbitmap.o
 util-obj-y += fifo8.o
diff --git a/util/qemu-openpty.c b/util/qemu-openpty.c
new file mode 100644
index 0000000..6d7bd4b
--- /dev/null
+++ b/util/qemu-openpty.c
@@ -0,0 +1,135 @@ 
+/*
+ * qemu-openpty.c
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2010 Red Hat, Inc.
+ *
+ * Wrapper function qemu_openpty() implementation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/*
+ * This is not part of oslib-posix.c because this function
+ * uses openpty() which often in -lutil, and if we add this
+ * dependency to oslib-posix.o, every app will have to be
+ * linked with -lutil.
+ */
+
+#include "config-host.h"
+#include "qemu-common.h"
+
+#if defined(__GLIBC__)
+# include <pty.h>
+#elif defined CONFIG_BSD
+# include <termios.h>
+# if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
+#  include <libutil.h>
+# else
+#  include <util.h>
+# endif
+#elif defined CONFIG_SOLARIS
+# include <stropts.h>
+#endif
+
+#ifdef __sun__
+/* Once Solaris has openpty(), this is going to be removed. */
+static int openpty(int *amaster, int *aslave, char *name,
+                   struct termios *termp, struct winsize *winp)
+{
+        const char *slave;
+        int mfd = -1, sfd = -1;
+
+        *amaster = *aslave = -1;
+
+        mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
+        if (mfd < 0)
+                goto err;
+
+        if (grantpt(mfd) == -1 || unlockpt(mfd) == -1)
+                goto err;
+
+        if ((slave = ptsname(mfd)) == NULL)
+                goto err;
+
+        if ((sfd = open(slave, O_RDONLY | O_NOCTTY)) == -1)
+                goto err;
+
+        if (ioctl(sfd, I_PUSH, "ptem") == -1 ||
+            (termp != NULL && tcgetattr(sfd, termp) < 0))
+                goto err;
+
+        if (amaster)
+                *amaster = mfd;
+        if (aslave)
+                *aslave = sfd;
+        if (winp)
+                ioctl(sfd, TIOCSWINSZ, winp);
+
+        return 0;
+
+err:
+        if (sfd != -1)
+                close(sfd);
+        close(mfd);
+        return -1;
+}
+
+static void cfmakeraw (struct termios *termios_p)
+{
+        termios_p->c_iflag &=
+                ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
+        termios_p->c_oflag &= ~OPOST;
+        termios_p->c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
+        termios_p->c_cflag &= ~(CSIZE|PARENB);
+        termios_p->c_cflag |= CS8;
+
+        termios_p->c_cc[VMIN] = 0;
+        termios_p->c_cc[VTIME] = 0;
+}
+#endif
+
+int qemu_openpty_raw(int *aslave, char *pty_name)
+{
+    int amaster;
+    struct termios tty;
+#if defined(__OpenBSD__) || defined(__DragonFly__)
+    char pty_buf[PATH_MAX];
+#define q_ptsname(x) pty_buf
+#else
+    char *pty_buf = NULL;
+#define q_ptsname(x) ptsname(x)
+#endif
+
+    if (openpty(&amaster, aslave, pty_buf, NULL, NULL) < 0) {
+        return -1;
+    }
+
+    /* Set raw attributes on the pty. */
+    tcgetattr(*aslave, &tty);
+    cfmakeraw(&tty);
+    tcsetattr(*aslave, TCSAFLUSH, &tty);
+
+    if (pty_name) {
+        strcpy(pty_name, q_ptsname(amaster));
+    }
+
+    return amaster;
+}
+