Merge remote-tracking branch 'kraxel/chardev.1' into staging

# By Gerd Hoffmann
# Via Gerd Hoffmann
* kraxel/chardev.1:
  chardev: add pty chardev support to chardev-add (qmp)
  chardev: add socket chardev support to chardev-add (qmp)
  chardev: add parallel chardev support to chardev-add (qmp)
  chardev: add serial chardev support to chardev-add (qmp)
  chardev: add file chardev support to chardev-add (qmp)
  chardev: add hmp hotplug commands
  chardev: add qmp hotplug commands, with null chardev support
  chardev: reduce chardev ifdef mess a bit
  chardev: fix QemuOpts lifecycle
  chardev: add error reporting for qemu_chr_new_from_opts

hmp-commands.hx

@@ -1482,6 +1482,38 @@ Password is invalidated at the given time.  @var{nsec} are the seconds
 passed since 1970, i.e. unix epoch.
 
 @end table
+ETEXI
+
+    {
+        .name       = "chardev-add",
+        .args_type  = "args:s",
+        .params     = "args",
+        .help       = "add chardev",
+        .mhandler.cmd = hmp_chardev_add,
+    },
+
+STEXI
+@item chardev_add args
+@findex chardev_add
+
+chardev_add accepts the same parameters as the -chardev command line switch.
+
+ETEXI
+
+    {
+        .name       = "chardev-remove",
+        .args_type  = "id:s",
+        .params     = "id",
+        .help       = "remove chardev",
+        .mhandler.cmd = hmp_chardev_remove,
+    },
+
+STEXI
+@item chardev_remove id
+@findex chardev_remove
+
+Removes the chardev @var{id}.
+
 ETEXI
 
     {

hmp.c

@@ -1336,3 +1336,26 @@ void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict)
     qmp_nbd_server_stop(&errp);
     hmp_handle_error(mon, &errp);
 }
+
+void hmp_chardev_add(Monitor *mon, const QDict *qdict)
+{
+    const char *args = qdict_get_str(qdict, "args");
+    Error *err = NULL;
+    QemuOpts *opts;
+
+    opts = qemu_opts_parse(qemu_find_opts("chardev"), args, 1);
+    if (opts == NULL) {
+        error_setg(&err, "Parsing chardev args failed\n");
+    } else {
+        qemu_chr_new_from_opts(opts, NULL, &err);
+    }
+    hmp_handle_error(mon, &err);
+}
+
+void hmp_chardev_remove(Monitor *mon, const QDict *qdict)
+{
+    Error *local_err = NULL;
+
+    qmp_chardev_remove(qdict_get_str(qdict, "id"), &local_err);
+    hmp_handle_error(mon, &local_err);
+}

hmp.h

@@ -80,5 +80,7 @@ void hmp_screen_dump(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_start(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_add(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict);
+void hmp_chardev_add(Monitor *mon, const QDict *qdict);
+void hmp_chardev_remove(Monitor *mon, const QDict *qdict);
 
 #endif

include/char/char.h

@@ -75,6 +75,7 @@ struct CharDriverState {
     char *filename;
     int opened;
     int avail_connections;
+    QemuOpts *opts;
     QTAILQ_ENTRY(CharDriverState) next;
 };
 
@@ -89,7 +90,8 @@ struct CharDriverState {
  * Returns: a new character backend
  */
 CharDriverState *qemu_chr_new_from_opts(QemuOpts *opts,
-                                    void (*init)(struct CharDriverState *s));
+                                    void (*init)(struct CharDriverState *s),
+                                    Error **errp);
 
 /**
  * @qemu_chr_new:

qapi-schema.json

@@ -3017,3 +3017,107 @@
 # Since: 1.3.0
 ##
 { 'command': 'nbd-server-stop' }
+
+##
+# @ChardevFile:
+#
+# Configuration info for file chardevs.
+#
+# @in:  #optional The name of the input file
+# @out: The name of the output file
+#
+# Since: 1.4
+##
+{ 'type': 'ChardevFile', 'data': { '*in' : 'str',
+                                   'out' : 'str' } }
+
+##
+# @ChardevPort:
+#
+# Configuration info for device chardevs.
+#
+# @device: The name of the special file for the device,
+#          i.e. /dev/ttyS0 on Unix or COM1: on Windows
+# @type: What kind of device this is.
+#
+# Since: 1.4
+##
+{ 'enum': 'ChardevPortKind', 'data': [ 'serial',
+                                       'parallel' ] }
+
+{ 'type': 'ChardevPort', 'data': { 'device' : 'str',
+                                   'type'   : 'ChardevPortKind'} }
+
+##
+# @ChardevSocket:
+#
+# Configuration info for socket chardevs.
+#
+# @addr: socket address to listen on (server=true)
+#        or connect to (server=false)
+# @server: #optional create server socket (default: true)
+# @wait: #optional wait for connect (not used for server
+#        sockets, default: false)
+# @nodelay: #optional set TCP_NODELAY socket option (default: false)
+# @telnet: #optional enable telnet protocol (default: false)
+#
+# Since: 1.4
+##
+{ 'type': 'ChardevSocket', 'data': { 'addr'     : 'SocketAddress',
+                                     '*server'  : 'bool',
+                                     '*wait'    : 'bool',
+                                     '*nodelay' : 'bool',
+                                     '*telnet'  : 'bool' } }
+
+##
+# @ChardevBackend:
+#
+# Configuration info for the new chardev backend.
+#
+# Since: 1.4
+##
+{ 'type': 'ChardevDummy', 'data': { } }
+
+{ 'union': 'ChardevBackend', 'data': { 'file'   : 'ChardevFile',
+                                       'port'   : 'ChardevPort',
+                                       'socket' : 'ChardevSocket',
+                                       'pty'    : 'ChardevDummy',
+                                       'null'   : 'ChardevDummy' } }
+
+##
+# @ChardevReturn:
+#
+# Return info about the chardev backend just created.
+#
+# Since: 1.4
+##
+{ 'type' : 'ChardevReturn', 'data': { '*pty' : 'str' } }
+
+##
+# @chardev-add:
+#
+# Add a file chardev
+#
+# @id: the chardev's ID, must be unique
+# @backend: backend type and parameters
+#
+# Returns: chardev info.
+#
+# Since: 1.4
+##
+{ 'command': 'chardev-add', 'data': {'id'      : 'str',
+                                     'backend' : 'ChardevBackend' },
+  'returns': 'ChardevReturn' }
+
+##
+# @chardev-remove:
+#
+# Remove a chardev
+#
+# @id: the chardev's ID, must exist and not be in use
+#
+# Returns: Nothing on success
+#
+# Since: 1.4
+##
+{ 'command': 'chardev-remove', 'data': {'id': 'str'} }

qemu-char.c

@@ -856,6 +856,8 @@ static void cfmakeraw (struct termios *termios_p)
     || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \
     || defined(__GLIBC__)
 
+#define HAVE_CHARDEV_TTY 1
+
 typedef struct {
     int fd;
     int connected;
@@ -1228,30 +1230,34 @@ static void qemu_chr_close_tty(CharDriverState *chr)
     }
 }
 
-static CharDriverState *qemu_chr_open_tty(QemuOpts *opts)
+static CharDriverState *qemu_chr_open_tty_fd(int fd)
 {
-    const char *filename = qemu_opt_get(opts, "path");
     CharDriverState *chr;
-    int fd;
 
-    TFR(fd = qemu_open(filename, O_RDWR | O_NONBLOCK));
-    if (fd < 0) {
-        return NULL;
-    }
     tty_serial_init(fd, 115200, 'N', 8, 1);
     chr = qemu_chr_open_fd(fd, fd);
     chr->chr_ioctl = tty_serial_ioctl;
     chr->chr_close = qemu_chr_close_tty;
     return chr;
 }
-#else  /* ! __linux__ && ! __sun__ */
-static CharDriverState *qemu_chr_open_pty(QemuOpts *opts)
+
+static CharDriverState *qemu_chr_open_tty(QemuOpts *opts)
 {
-    return NULL;
+    const char *filename = qemu_opt_get(opts, "path");
+    int fd;
+
+    TFR(fd = qemu_open(filename, O_RDWR | O_NONBLOCK));
+    if (fd < 0) {
+        return NULL;
+    }
+    return qemu_chr_open_tty_fd(fd);
 }
 #endif /* __linux__ || __sun__ */
 
 #if defined(__linux__)
+
+#define HAVE_CHARDEV_PARPORT 1
+
 typedef struct {
     int fd;
     int mode;
@@ -1361,17 +1367,10 @@ static void pp_close(CharDriverState *chr)
     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
 }
 
-static CharDriverState *qemu_chr_open_pp(QemuOpts *opts)
+static CharDriverState *qemu_chr_open_pp_fd(int fd)
 {
-    const char *filename = qemu_opt_get(opts, "path");
     CharDriverState *chr;
     ParallelCharDriver *drv;
-    int fd;
-
-    TFR(fd = qemu_open(filename, O_RDWR));
-    if (fd < 0) {
-        return NULL;
-    }
 
     if (ioctl(fd, PPCLAIM) < 0) {
         close(fd);
@@ -1395,6 +1394,9 @@ static CharDriverState *qemu_chr_open_pp(QemuOpts *opts)
 #endif /* __linux__ */
 
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
+
+#define HAVE_CHARDEV_PARPORT 1
+
 static int pp_ioctl(CharDriverState *chr, int cmd, void *arg)
 {
     int fd = (int)(intptr_t)chr->opaque;
@@ -1432,16 +1434,9 @@ static int pp_ioctl(CharDriverState *chr, int cmd, void *arg)
     return 0;
 }
 
-static CharDriverState *qemu_chr_open_pp(QemuOpts *opts)
+static CharDriverState *qemu_chr_open_pp_fd(int fd)
 {
-    const char *filename = qemu_opt_get(opts, "path");
     CharDriverState *chr;
-    int fd;
-
-    fd = qemu_open(filename, O_RDWR);
-    if (fd < 0) {
-        return NULL;
-    }
 
     chr = g_malloc0(sizeof(CharDriverState));
     chr->opaque = (void *)(intptr_t)fd;
@@ -1663,9 +1658,8 @@ static int win_chr_poll(void *opaque)
     return 0;
 }
 
-static CharDriverState *qemu_chr_open_win(QemuOpts *opts)
+static CharDriverState *qemu_chr_open_win_path(const char *filename)
 {
-    const char *filename = qemu_opt_get(opts, "path");
     CharDriverState *chr;
     WinCharState *s;
 
@@ -1684,6 +1678,11 @@ static CharDriverState *qemu_chr_open_win(QemuOpts *opts)
     return chr;
 }
 
+static CharDriverState *qemu_chr_open_win(QemuOpts *opts)
+{
+    return qemu_chr_open_win_path(qemu_opt_get(opts, "path"));
+}
+
 static int win_chr_pipe_poll(void *opaque)
 {
     CharDriverState *chr = opaque;
@@ -2439,10 +2438,88 @@ static void tcp_chr_close(CharDriverState *chr)
     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
 }
 
-static CharDriverState *qemu_chr_open_socket(QemuOpts *opts)
+static CharDriverState *qemu_chr_open_socket_fd(int fd, bool do_nodelay,
+                                                bool is_listen, bool is_telnet,
+                                                bool is_waitconnect,
+                                                Error **errp)
 {
     CharDriverState *chr = NULL;
     TCPCharDriver *s = NULL;
+    char host[NI_MAXHOST], serv[NI_MAXSERV];
+    const char *left = "", *right = "";
+    struct sockaddr_storage ss;
+    socklen_t ss_len = sizeof(ss);
+
+    memset(&ss, 0, ss_len);
+    if (getsockname(fd, (struct sockaddr *) &ss, &ss_len) != 0) {
+        error_setg(errp, "getsockname: %s", strerror(errno));
+        return NULL;
+    }
+
+    chr = g_malloc0(sizeof(CharDriverState));
+    s = g_malloc0(sizeof(TCPCharDriver));
+
+    s->connected = 0;
+    s->fd = -1;
+    s->listen_fd = -1;
+    s->msgfd = -1;
+
+    chr->filename = g_malloc(256);
+    switch (ss.ss_family) {
+#ifndef _WIN32
+    case AF_UNIX:
+        s->is_unix = 1;
+        snprintf(chr->filename, 256, "unix:%s%s",
+                 ((struct sockaddr_un *)(&ss))->sun_path,
+                 is_listen ? ",server" : "");
+        break;
+#endif
+    case AF_INET6:
+        left  = "[";
+        right = "]";
+        /* fall through */
+    case AF_INET:
+        s->do_nodelay = do_nodelay;
+        getnameinfo((struct sockaddr *) &ss, ss_len, host, sizeof(host),
+                    serv, sizeof(serv), NI_NUMERICHOST | NI_NUMERICSERV);
+        snprintf(chr->filename, 256, "%s:%s:%s%s%s%s",
+                 is_telnet ? "telnet" : "tcp",
+                 left, host, right, serv,
+                 is_listen ? ",server" : "");
+        break;
+    }
+
+    chr->opaque = s;
+    chr->chr_write = tcp_chr_write;
+    chr->chr_close = tcp_chr_close;
+    chr->get_msgfd = tcp_get_msgfd;
+    chr->chr_add_client = tcp_chr_add_client;
+
+    if (is_listen) {
+        s->listen_fd = fd;
+        qemu_set_fd_handler2(s->listen_fd, NULL, tcp_chr_accept, NULL, chr);
+        if (is_telnet) {
+            s->do_telnetopt = 1;
+        }
+    } else {
+        s->connected = 1;
+        s->fd = fd;
+        socket_set_nodelay(fd);
+        tcp_chr_connect(chr);
+    }
+
+    if (is_listen && is_waitconnect) {
+        printf("QEMU waiting for connection on: %s\n",
+               chr->filename);
+        tcp_chr_accept(chr);
+        socket_set_nonblock(s->listen_fd);
+    }
+    return chr;
+}
+
+static CharDriverState *qemu_chr_open_socket(QemuOpts *opts)
+{
+    CharDriverState *chr = NULL;
     Error *local_err = NULL;
     int fd = -1;
     int is_listen;
@@ -2459,9 +2536,6 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts *opts)
     if (!is_listen)
         is_waitconnect = 0;
 
-    chr = g_malloc0(sizeof(CharDriverState));
-    s = g_malloc0(sizeof(TCPCharDriver));
-
     if (is_unix) {
         if (is_listen) {
             fd = unix_listen_opts(opts, &local_err);
@@ -2482,56 +2556,14 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts *opts)
     if (!is_waitconnect)
         socket_set_nonblock(fd);
 
-    s->connected = 0;
-    s->fd = -1;
-    s->listen_fd = -1;
-    s->msgfd = -1;
-    s->is_unix = is_unix;
-    s->do_nodelay = do_nodelay && !is_unix;
-
-    chr->opaque = s;
-    chr->chr_write = tcp_chr_write;
-    chr->chr_close = tcp_chr_close;
-    chr->get_msgfd = tcp_get_msgfd;
-    chr->chr_add_client = tcp_chr_add_client;
-
-    if (is_listen) {
-        s->listen_fd = fd;
-        qemu_set_fd_handler2(s->listen_fd, NULL, tcp_chr_accept, NULL, chr);
-        if (is_telnet)
-            s->do_telnetopt = 1;
-
-    } else {
-        s->connected = 1;
-        s->fd = fd;
-        socket_set_nodelay(fd);
-        tcp_chr_connect(chr);
-    }
-
-    /* for "info chardev" monitor command */
-    chr->filename = g_malloc(256);
-    if (is_unix) {
-        snprintf(chr->filename, 256, "unix:%s%s",
-                 qemu_opt_get(opts, "path"),
-                 qemu_opt_get_bool(opts, "server", 0) ? ",server" : "");
-    } else if (is_telnet) {
-        snprintf(chr->filename, 256, "telnet:%s:%s%s",
-                 qemu_opt_get(opts, "host"), qemu_opt_get(opts, "port"),
-                 qemu_opt_get_bool(opts, "server", 0) ? ",server" : "");
-    } else {
-        snprintf(chr->filename, 256, "tcp:%s:%s%s",
-                 qemu_opt_get(opts, "host"), qemu_opt_get(opts, "port"),
-                 qemu_opt_get_bool(opts, "server", 0) ? ",server" : "");
-    }
-
-    if (is_listen && is_waitconnect) {
-        printf("QEMU waiting for connection on: %s\n",
-               chr->filename);
-        tcp_chr_accept(chr);
-        socket_set_nonblock(s->listen_fd);
+    chr = qemu_chr_open_socket_fd(fd, do_nodelay, is_listen, is_telnet,
+                                  is_waitconnect, &local_err);
+    if (error_is_set(&local_err)) {
+        goto fail;
     }
     return chr;
 
+
  fail:
     if (local_err) {
         qerror_report_err(local_err);
@@ -2540,8 +2572,10 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts *opts)
     if (fd >= 0) {
         closesocket(fd);
     }
-    g_free(s);
-    g_free(chr);
+    if (chr) {
+        g_free(chr->opaque);
+        g_free(chr);
+    }
     return NULL;
 }
 
@@ -2737,6 +2771,22 @@ fail:
     return NULL;
 }
 
+#ifdef HAVE_CHARDEV_PARPORT
+
+static CharDriverState *qemu_chr_open_pp(QemuOpts *opts)
+{
+    const char *filename = qemu_opt_get(opts, "path");
+    int fd;
+
+    fd = qemu_open(filename, O_RDWR);
+    if (fd < 0) {
+        return NULL;
+    }
+    return qemu_chr_open_pp_fd(fd);
+}
+
+#endif
+
 static const struct {
     const char *name;
     CharDriverState *(*open)(QemuOpts *opts);
@@ -2755,19 +2805,18 @@ static const struct {
 #else
     { .name = "file",      .open = qemu_chr_open_file_out },
     { .name = "pipe",      .open = qemu_chr_open_pipe },
-    { .name = "pty",       .open = qemu_chr_open_pty },
     { .name = "stdio",     .open = qemu_chr_open_stdio },
 #endif
 #ifdef CONFIG_BRLAPI
     { .name = "braille",   .open = chr_baum_init },
 #endif
-#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
-    || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \
-    || defined(__FreeBSD_kernel__)
+#ifdef HAVE_CHARDEV_TTY
     { .name = "tty",       .open = qemu_chr_open_tty },
+    { .name = "serial",    .open = qemu_chr_open_tty },
+    { .name = "pty",       .open = qemu_chr_open_pty },
 #endif
-#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) \
-    || defined(__FreeBSD_kernel__)
+#ifdef HAVE_CHARDEV_PARPORT
+    { .name = "parallel",  .open = qemu_chr_open_pp },
     { .name = "parport",   .open = qemu_chr_open_pp },
 #endif
 #ifdef CONFIG_SPICE
@@ -2779,36 +2828,37 @@ static const struct {
 };
 
 CharDriverState *qemu_chr_new_from_opts(QemuOpts *opts,
-                                    void (*init)(struct CharDriverState *s))
+                                    void (*init)(struct CharDriverState *s),
+                                    Error **errp)
 {
     CharDriverState *chr;
     int i;
 
     if (qemu_opts_id(opts) == NULL) {
-        fprintf(stderr, "chardev: no id specified\n");
-        return NULL;
+        error_setg(errp, "chardev: no id specified\n");
+        goto err;
     }
 
     if (qemu_opt_get(opts, "backend") == NULL) {
-        fprintf(stderr, "chardev: \"%s\" missing backend\n",
-                qemu_opts_id(opts));
-        return NULL;
+        error_setg(errp, "chardev: \"%s\" missing backend\n",
+                   qemu_opts_id(opts));
+        goto err;
     }
     for (i = 0; i < ARRAY_SIZE(backend_table); i++) {
         if (strcmp(backend_table[i].name, qemu_opt_get(opts, "backend")) == 0)
             break;
     }
     if (i == ARRAY_SIZE(backend_table)) {
-        fprintf(stderr, "chardev: backend \"%s\" not found\n",
-                qemu_opt_get(opts, "backend"));
-        return NULL;
+        error_setg(errp, "chardev: backend \"%s\" not found\n",
+                   qemu_opt_get(opts, "backend"));
+        goto err;
     }
 
     chr = backend_table[i].open(opts);
     if (!chr) {
-        fprintf(stderr, "chardev: opening backend \"%s\" failed\n",
-                qemu_opt_get(opts, "backend"));
-        return NULL;
+        error_setg(errp, "chardev: opening backend \"%s\" failed\n",
+                   qemu_opt_get(opts, "backend"));
+        goto err;
     }
 
     if (!chr->filename)
@@ -2829,7 +2879,12 @@ CharDriverState *qemu_chr_new_from_opts(QemuOpts *opts,
         chr->avail_connections = 1;
     }
     chr->label = g_strdup(qemu_opts_id(opts));
+    chr->opts = opts;
     return chr;
+
+err:
+    qemu_opts_del(opts);
+    return NULL;
 }
 
 CharDriverState *qemu_chr_new(const char *label, const char *filename, void (*init)(struct CharDriverState *s))
@@ -2837,6 +2892,7 @@ CharDriverState *qemu_chr_new(const char *label, const char *filename, void (*in
     const char *p;
     CharDriverState *chr;
     QemuOpts *opts;
+    Error *err = NULL;
 
     if (strstart(filename, "chardev:", &p)) {
         return qemu_chr_find(p);
@@ -2846,11 +2902,14 @@ CharDriverState *qemu_chr_new(const char *label, const char *filename, void (*in
     if (!opts)
         return NULL;
 
-    chr = qemu_chr_new_from_opts(opts, init);
+    chr = qemu_chr_new_from_opts(opts, init, &err);
+    if (error_is_set(&err)) {
+        fprintf(stderr, "%s\n", error_get_pretty(err));
+        error_free(err);
+    }
     if (chr && qemu_opt_get_bool(opts, "mux", 0)) {
         monitor_init(chr, MONITOR_USE_READLINE);
     }
-    qemu_opts_del(opts);
     return chr;
 }
 
@@ -2878,10 +2937,14 @@ void qemu_chr_fe_close(struct CharDriverState *chr)
 void qemu_chr_delete(CharDriverState *chr)
 {
     QTAILQ_REMOVE(&chardevs, chr, next);
-    if (chr->chr_close)
+    if (chr->chr_close) {
         chr->chr_close(chr);
+    }
     g_free(chr->filename);
     g_free(chr->label);
+    if (chr->opts) {
+        qemu_opts_del(chr->opts);
+    }
     g_free(chr);
 }
 
@@ -2996,3 +3059,199 @@ QemuOptsList qemu_chardev_opts = {
         { /* end of list */ }
     },
 };
+
+#ifdef _WIN32
+
+static CharDriverState *qmp_chardev_open_file(ChardevFile *file, Error **errp)
+{
+    HANDLE out;
+
+    if (file->in) {
+        error_setg(errp, "input file not supported");
+        return NULL;
+    }
+
+    out = CreateFile(file->out, GENERIC_WRITE, FILE_SHARE_READ, NULL,
+                     OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+    if (out == INVALID_HANDLE_VALUE) {
+        error_setg(errp, "open %s failed", file->out);
+        return NULL;
+    }
+    return qemu_chr_open_win_file(out);
+}
+
+static CharDriverState *qmp_chardev_open_port(ChardevPort *port, Error **errp)
+{
+    switch (port->type) {
+    case CHARDEV_PORT_KIND_SERIAL:
+        return qemu_chr_open_win_path(port->device);
+    default:
+        error_setg(errp, "unknown chardev port (%d)", port->type);
+        return NULL;
+    }
+}
+
+#else /* WIN32 */
+
+static int qmp_chardev_open_file_source(char *src, int flags,
+                                        Error **errp)
+{
+    int fd = -1;
+
+    TFR(fd = qemu_open(src, flags, 0666));
+    if (fd == -1) {
+        error_setg(errp, "open %s: %s", src, strerror(errno));
+    }
+    return fd;
+}
+
+static CharDriverState *qmp_chardev_open_file(ChardevFile *file, Error **errp)
+{
+    int flags, in = -1, out = -1;
+
+    flags = O_WRONLY | O_TRUNC | O_CREAT | O_BINARY;
+    out = qmp_chardev_open_file_source(file->out, flags, errp);
+    if (error_is_set(errp)) {
+        return NULL;
+    }
+
+    if (file->in) {
+        flags = O_RDONLY;
+        in = qmp_chardev_open_file_source(file->in, flags, errp);
+        if (error_is_set(errp)) {
+            qemu_close(out);
+            return NULL;
+        }
+    }
+
+    return qemu_chr_open_fd(in, out);
+}
+
+static CharDriverState *qmp_chardev_open_port(ChardevPort *port, Error **errp)
+{
+    int flags, fd;
+
+    switch (port->type) {
+#ifdef HAVE_CHARDEV_TTY
+    case CHARDEV_PORT_KIND_SERIAL:
+        flags = O_RDWR;
+        fd = qmp_chardev_open_file_source(port->device, flags, errp);
+        if (error_is_set(errp)) {
+            return NULL;
+        }
+        socket_set_nonblock(fd);
+        return qemu_chr_open_tty_fd(fd);
+#endif
+#ifdef HAVE_CHARDEV_PARPORT
+    case CHARDEV_PORT_KIND_PARALLEL:
+        flags = O_RDWR;
+        fd = qmp_chardev_open_file_source(port->device, flags, errp);
+        if (error_is_set(errp)) {
+            return NULL;
+        }
+        return qemu_chr_open_pp_fd(fd);
+#endif
+    default:
+        error_setg(errp, "unknown chardev port (%d)", port->type);
+        return NULL;
+    }
+}
+
+#endif /* WIN32 */
+
+static CharDriverState *qmp_chardev_open_socket(ChardevSocket *sock,
+                                                Error **errp)
+{
+    SocketAddress *addr = sock->addr;
+    bool do_nodelay     = sock->has_nodelay ? sock->nodelay : false;
+    bool is_listen      = sock->has_server  ? sock->server  : true;
+    bool is_telnet      = sock->has_telnet  ? sock->telnet  : false;
+    bool is_waitconnect = sock->has_wait    ? sock->wait    : false;
+    int fd;
+
+    if (is_listen) {
+        fd = socket_listen(addr, errp);
+    } else {
+        fd = socket_connect(addr, errp, NULL, NULL);
+    }
+    if (error_is_set(errp)) {
+        return NULL;
+    }
+    return qemu_chr_open_socket_fd(fd, do_nodelay, is_listen,
+                                   is_telnet, is_waitconnect, errp);
+}
+
+ChardevReturn *qmp_chardev_add(const char *id, ChardevBackend *backend,
+                               Error **errp)
+{
+    ChardevReturn *ret = g_new0(ChardevReturn, 1);
+    CharDriverState *chr = NULL;
+
+    chr = qemu_chr_find(id);
+    if (chr) {
+        error_setg(errp, "Chardev '%s' already exists", id);
+        g_free(ret);
+        return NULL;
+    }
+
+    switch (backend->kind) {
+    case CHARDEV_BACKEND_KIND_FILE:
+        chr = qmp_chardev_open_file(backend->file, errp);
+        break;
+    case CHARDEV_BACKEND_KIND_PORT:
+        chr = qmp_chardev_open_port(backend->port, errp);
+        break;
+    case CHARDEV_BACKEND_KIND_SOCKET:
+        chr = qmp_chardev_open_socket(backend->socket, errp);
+        break;
+#ifdef HAVE_CHARDEV_TTY
+    case CHARDEV_BACKEND_KIND_PTY:
+    {
+        /* qemu_chr_open_pty sets "path" in opts */
+        QemuOpts *opts;
+        opts = qemu_opts_create_nofail(qemu_find_opts("chardev"));
+        chr = qemu_chr_open_pty(opts);
+        ret->pty = g_strdup(qemu_opt_get(opts, "path"));
+        ret->has_pty = true;
+        qemu_opts_del(opts);
+        break;
+    }
+#endif
+    case CHARDEV_BACKEND_KIND_NULL:
+        chr = qemu_chr_open_null(NULL);
+        break;
+    default:
+        error_setg(errp, "unknown chardev backend (%d)", backend->kind);
+        break;
+    }
+
+    if (chr == NULL && !error_is_set(errp)) {
+        error_setg(errp, "Failed to create chardev");
+    }
+    if (chr) {
+        chr->label = g_strdup(id);
+        chr->avail_connections = 1;
+        QTAILQ_INSERT_TAIL(&chardevs, chr, next);
+        return ret;
+    } else {
+        g_free(ret);
+        return NULL;
+    }
+}
+
+void qmp_chardev_remove(const char *id, Error **errp)
+{
+    CharDriverState *chr;
+
+    chr = qemu_chr_find(id);
+    if (NULL == chr) {
+        error_setg(errp, "Chardev '%s' not found", id);
+        return;
+    }
+    if (chr->chr_can_read || chr->chr_read ||
+        chr->chr_event || chr->handler_opaque) {
+        error_setg(errp, "Chardev '%s' is busy", id);
+        return;
+    }
+    qemu_chr_delete(chr);
+}

qemu-options.hx

@@ -1742,9 +1742,11 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
 #endif
 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
         || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
+    "-chardev serial,id=id,path=path[,mux=on|off]\n"
     "-chardev tty,id=id,path=path[,mux=on|off]\n"
 #endif
 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
+    "-chardev parallel,id=id,path=path[,mux=on|off]\n"
     "-chardev parport,id=id,path=path[,mux=on|off]\n"
 #endif
 #if defined(CONFIG_SPICE)
@@ -1775,6 +1777,7 @@ Backend is one of:
 @option{stdio},
 @option{braille},
 @option{tty},
+@option{parallel},
 @option{parport},
 @option{spicevmc}.
 @option{spiceport}.
@@ -1910,8 +1913,8 @@ take any options.
 
 Send traffic from the guest to a serial device on the host.
 
-@option{serial} is
-only available on Windows hosts.
+On Unix hosts serial will actually accept any tty device,
+not only serial lines.
 
 @option{path} specifies the name of the serial device to open.
 
@@ -1937,16 +1940,15 @@ Connect to a local BrlAPI server. @option{braille} does not take any options.
 
 @item -chardev tty ,id=@var{id} ,path=@var{path}
 
-Connect to a local tty device.
-
 @option{tty} is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD and
-DragonFlyBSD hosts.
+DragonFlyBSD hosts.  It is an alias for -serial.
 
 @option{path} specifies the path to the tty. @option{path} is required.
 
+@item -chardev parallel ,id=@var{id} ,path=@var{path}
 @item -chardev parport ,id=@var{id} ,path=@var{path}
 
-@option{parport} is only available on Linux, FreeBSD and DragonFlyBSD hosts.
+@option{parallel} is only available on Linux, FreeBSD and DragonFlyBSD hosts.
 
 Connect to a local parallel port.
 

qmp-commands.hx

@@ -2654,3 +2654,64 @@ EQMP
         .args_type  = "",
         .mhandler.cmd_new = qmp_marshal_input_query_target,
     },
+
+    {
+        .name       = "chardev-add",
+        .args_type  = "id:s,backend:q",
+        .mhandler.cmd_new = qmp_marshal_input_chardev_add,
+    },
+
+SQMP
+chardev-add
+----------------
+
+Add a chardev.
+
+Arguments:
+
+- "id": the chardev's ID, must be unique (json-string)
+- "backend": chardev backend type + parameters
+
+Examples:
+
+-> { "execute" : "chardev-add",
+     "arguments" : { "id" : "foo",
+                     "backend" : { "type" : "null", "data" : {} } } }
+<- { "return": {} }
+
+-> { "execute" : "chardev-add",
+     "arguments" : { "id" : "bar",
+                     "backend" : { "type" : "file",
+                                   "data" : { "out" : "/tmp/bar.log" } } } }
+<- { "return": {} }
+
+-> { "execute" : "chardev-add",
+     "arguments" : { "id" : "baz",
+                     "backend" : { "type" : "pty", "data" : {} } } }
+<- { "return": { "pty" : "/dev/pty/42" } }
+
+EQMP
+
+    {
+        .name       = "chardev-remove",
+        .args_type  = "id:s",
+        .mhandler.cmd_new = qmp_marshal_input_chardev_remove,
+    },
+
+
+SQMP
+chardev-remove
+--------------
+
+Remove a chardev.
+
+Arguments:
+
+- "id": the chardev's ID, must exist and not be in use (json-string)
+
+Example:
+
+-> { "execute": "chardev-remove", "arguments": { "id" : "foo" } }
+<- { "return": {} }
+
+EQMP

vl.c

@@ -2238,11 +2238,14 @@ static int device_init_func(QemuOpts *opts, void *opaque)
 
 static int chardev_init_func(QemuOpts *opts, void *opaque)
 {
-    CharDriverState *chr;
+    Error *local_err = NULL;
 
-    chr = qemu_chr_new_from_opts(opts, NULL);
-    if (!chr)
+    qemu_chr_new_from_opts(opts, NULL, &local_err);
+    if (error_is_set(&local_err)) {
+        fprintf(stderr, "%s\n", error_get_pretty(local_err));
+        error_free(local_err);
         return -1;
+    }
     return 0;
 }