char: move QIOChannel-related stuff to char-io.h

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

chardev/Makefile.objs

@@ -1,4 +1,5 @@
 chardev-obj-y += char.o
+chardev-obj-y += char-io.o
 chardev-obj-y += char-mux.o
 chardev-obj-y += char-null.o
 chardev-obj-y += char-ringbuf.o

chardev/char-io.c

@@ -0,0 +1,192 @@
+/*
+ * 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 "char-io.h"
+
+typedef struct IOWatchPoll {
+    GSource parent;
+
+    QIOChannel *ioc;
+    GSource *src;
+
+    IOCanReadHandler *fd_can_read;
+    GSourceFunc fd_read;
+    void *opaque;
+    GMainContext *context;
+} IOWatchPoll;
+
+static IOWatchPoll *io_watch_poll_from_source(GSource *source)
+{
+    return container_of(source, IOWatchPoll, parent);
+}
+
+static gboolean io_watch_poll_prepare(GSource *source,
+                                      gint *timeout)
+{
+    IOWatchPoll *iwp = io_watch_poll_from_source(source);
+    bool now_active = iwp->fd_can_read(iwp->opaque) > 0;
+    bool was_active = iwp->src != NULL;
+    if (was_active == now_active) {
+        return FALSE;
+    }
+
+    if (now_active) {
+        iwp->src = qio_channel_create_watch(
+            iwp->ioc, G_IO_IN | G_IO_ERR | G_IO_HUP | G_IO_NVAL);
+        g_source_set_callback(iwp->src, iwp->fd_read, iwp->opaque, NULL);
+        g_source_attach(iwp->src, iwp->context);
+    } else {
+        g_source_destroy(iwp->src);
+        g_source_unref(iwp->src);
+        iwp->src = NULL;
+    }
+    return FALSE;
+}
+
+static gboolean io_watch_poll_check(GSource *source)
+{
+    return FALSE;
+}
+
+static gboolean io_watch_poll_dispatch(GSource *source, GSourceFunc callback,
+                                       gpointer user_data)
+{
+    abort();
+}
+
+static void io_watch_poll_finalize(GSource *source)
+{
+    /* Due to a glib bug, removing the last reference to a source
+     * inside a finalize callback causes recursive locking (and a
+     * deadlock).  This is not a problem inside other callbacks,
+     * including dispatch callbacks, so we call io_remove_watch_poll
+     * to remove this source.  At this point, iwp->src must
+     * be NULL, or we would leak it.
+     *
+     * This would be solved much more elegantly by child sources,
+     * but we support older glib versions that do not have them.
+     */
+    IOWatchPoll *iwp = io_watch_poll_from_source(source);
+    assert(iwp->src == NULL);
+}
+
+static GSourceFuncs io_watch_poll_funcs = {
+    .prepare = io_watch_poll_prepare,
+    .check = io_watch_poll_check,
+    .dispatch = io_watch_poll_dispatch,
+    .finalize = io_watch_poll_finalize,
+};
+
+guint io_add_watch_poll(Chardev *chr,
+                        QIOChannel *ioc,
+                        IOCanReadHandler *fd_can_read,
+                        QIOChannelFunc fd_read,
+                        gpointer user_data,
+                        GMainContext *context)
+{
+    IOWatchPoll *iwp;
+    int tag;
+    char *name;
+
+    iwp = (IOWatchPoll *) g_source_new(&io_watch_poll_funcs,
+                                       sizeof(IOWatchPoll));
+    iwp->fd_can_read = fd_can_read;
+    iwp->opaque = user_data;
+    iwp->ioc = ioc;
+    iwp->fd_read = (GSourceFunc) fd_read;
+    iwp->src = NULL;
+    iwp->context = context;
+
+    name = g_strdup_printf("chardev-iowatch-%s", chr->label);
+    g_source_set_name((GSource *)iwp, name);
+    g_free(name);
+
+    tag = g_source_attach(&iwp->parent, context);
+    g_source_unref(&iwp->parent);
+    return tag;
+}
+
+static void io_remove_watch_poll(guint tag)
+{
+    GSource *source;
+    IOWatchPoll *iwp;
+
+    g_return_if_fail(tag > 0);
+
+    source = g_main_context_find_source_by_id(NULL, tag);
+    g_return_if_fail(source != NULL);
+
+    iwp = io_watch_poll_from_source(source);
+    if (iwp->src) {
+        g_source_destroy(iwp->src);
+        g_source_unref(iwp->src);
+        iwp->src = NULL;
+    }
+    g_source_destroy(&iwp->parent);
+}
+
+void remove_fd_in_watch(Chardev *chr)
+{
+    if (chr->fd_in_tag) {
+        io_remove_watch_poll(chr->fd_in_tag);
+        chr->fd_in_tag = 0;
+    }
+}
+
+int io_channel_send_full(QIOChannel *ioc,
+                         const void *buf, size_t len,
+                         int *fds, size_t nfds)
+{
+    size_t offset = 0;
+
+    while (offset < len) {
+        ssize_t ret = 0;
+        struct iovec iov = { .iov_base = (char *)buf + offset,
+                             .iov_len = len - offset };
+
+        ret = qio_channel_writev_full(
+            ioc, &iov, 1,
+            fds, nfds, NULL);
+        if (ret == QIO_CHANNEL_ERR_BLOCK) {
+            if (offset) {
+                return offset;
+            }
+
+            errno = EAGAIN;
+            return -1;
+        } else if (ret < 0) {
+            errno = EINVAL;
+            return -1;
+        }
+
+        offset += ret;
+    }
+
+    return offset;
+}
+
+int io_channel_send(QIOChannel *ioc, const void *buf, size_t len)
+{
+    return io_channel_send_full(ioc, buf, len, NULL, 0);
+}

chardev/char-io.h

@@ -0,0 +1,46 @@
+/*
+ * 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.
+ */
+#ifndef CHAR_IO_H
+#define CHAR_IO_H
+
+#include "qemu-common.h"
+#include "io/channel.h"
+#include "sysemu/char.h"
+
+/* Can only be used for read */
+guint io_add_watch_poll(Chardev *chr,
+                        QIOChannel *ioc,
+                        IOCanReadHandler *fd_can_read,
+                        QIOChannelFunc fd_read,
+                        gpointer user_data,
+                        GMainContext *context);
+
+void remove_fd_in_watch(Chardev *chr);
+
+int io_channel_send(QIOChannel *ioc, const void *buf, size_t len);
+
+int io_channel_send_full(QIOChannel *ioc, const void *buf, size_t len,
+                         int *fds, size_t nfds);
+
+#endif /* CHAR_IO_H */