Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 166 insertions, 0 deletions

diff --git a/chardev/char-stdio.c b/chardev/char-stdio.c
new file mode 100644
index 000000000..403da308c
--- /dev/null
+++ b/chardev/char-stdio.c
@@ -0,0 +1,166 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * 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.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/module.h"
+#include "qemu/option.h"
+#include "qemu/sockets.h"
+#include "qapi/error.h"
+#include "chardev/char.h"
+
+#ifdef _WIN32
+#include "chardev/char-win.h"
+#include "chardev/char-win-stdio.h"
+#else
+#include <termios.h>
+#include "chardev/char-fd.h"
+#endif
+
+#ifndef _WIN32
+/* init terminal so that we can grab keys */
+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 term_exit(void)
+{
+    if (stdio_in_use) {
+        tcsetattr(0, TCSANOW, &oldtty);
+        fcntl(0, F_SETFL, old_fd0_flags);
+    }
+}
+
+static void qemu_chr_set_echo_stdio(Chardev *chr, bool echo)
+{
+    struct termios tty;
+
+    stdio_echo_state = echo;
+    tty = oldtty;
+    if (!echo) {
+        tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
+                         | INLCR | IGNCR | ICRNL | IXON);
+        tty.c_oflag |= OPOST;
+        tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
+        tty.c_cflag &= ~(CSIZE | PARENB);
+        tty.c_cflag |= CS8;
+        tty.c_cc[VMIN] = 1;
+        tty.c_cc[VTIME] = 0;
+    }
+    if (!stdio_allow_signal) {
+        tty.c_lflag &= ~ISIG;
+    }
+
+    tcsetattr(0, TCSANOW, &tty);
+}
+
+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_open_stdio(Chardev *chr,
+                                ChardevBackend *backend,
+                                bool *be_opened,
+                                Error **errp)
+{
+    ChardevStdio *opts = backend->u.stdio.data;
+    struct sigaction act;
+
+    if (is_daemonized()) {
+        error_setg(errp, "cannot use stdio with -daemonize");
+        return;
+    }
+
+    if (stdio_in_use) {
+        error_setg(errp, "cannot use stdio by multiple character devices");
+        return;
+    }
+
+    stdio_in_use = true;
+    old_fd0_flags = fcntl(0, F_GETFL);
+    tcgetattr(0, &oldtty);
+    qemu_set_nonblock(0);
+    atexit(term_exit);
+
+    memset(&act, 0, sizeof(act));
+    act.sa_handler = term_stdio_handler;
+    sigaction(SIGCONT, &act, NULL);
+
+    qemu_chr_open_fd(chr, 0, 1);
+
+    stdio_allow_signal = !opts->has_signal || opts->signal;
+    qemu_chr_set_echo_stdio(chr, false);
+}
+#endif
+
+static void qemu_chr_parse_stdio(QemuOpts *opts, ChardevBackend *backend,
+                                 Error **errp)
+{
+    ChardevStdio *stdio;
+
+    backend->type = CHARDEV_BACKEND_KIND_STDIO;
+    stdio = backend->u.stdio.data = g_new0(ChardevStdio, 1);
+    qemu_chr_parse_common(opts, qapi_ChardevStdio_base(stdio));
+    stdio->has_signal = true;
+    stdio->signal = qemu_opt_get_bool(opts, "signal", true);
+}
+
+static void char_stdio_class_init(ObjectClass *oc, void *data)
+{
+    ChardevClass *cc = CHARDEV_CLASS(oc);
+
+    cc->parse = qemu_chr_parse_stdio;
+#ifndef _WIN32
+    cc->open = qemu_chr_open_stdio;
+    cc->chr_set_echo = qemu_chr_set_echo_stdio;
+#endif
+}
+
+static void char_stdio_finalize(Object *obj)
+{
+#ifndef _WIN32
+    term_exit();
+#endif
+}
+
+static const TypeInfo char_stdio_type_info = {
+    .name = TYPE_CHARDEV_STDIO,
+#ifdef _WIN32
+    .parent = TYPE_CHARDEV_WIN_STDIO,
+#else
+    .parent = TYPE_CHARDEV_FD,
+#endif
+    .instance_finalize = char_stdio_finalize,
+    .class_init = char_stdio_class_init,
+};
+
+static void register_types(void)
+{
+    type_register_static(&char_stdio_type_info);
+}
+
+type_init(register_types);