chardev/char-io.c

   1 /*
   2  * QEMU System Emulator
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu/osdep.h"
  25 #include "chardev/char-io.h"
  26
  27 typedef struct IOWatchPoll {
  28     GSource parent;
  29
  30     QIOChannel *ioc;
  31     GSource *src;
  32
  33     IOCanReadHandler *fd_can_read;
  34     GSourceFunc fd_read;
  35     void *opaque;
  36 } IOWatchPoll;
  37
  38 static IOWatchPoll *io_watch_poll_from_source(GSource *source)
  39 {
  40     return container_of(source, IOWatchPoll, parent);
  41 }
  42
  43 static gboolean io_watch_poll_prepare(GSource *source,
  44                                       gint *timeout)
  45 {
  46     IOWatchPoll *iwp = io_watch_poll_from_source(source);
  47     bool now_active = iwp->fd_can_read(iwp->opaque) > 0;
  48     bool was_active = iwp->src != NULL;
  49     if (was_active == now_active) {
  50         return FALSE;
  51     }
  52
  53     if (now_active) {
  54         iwp->src = qio_channel_create_watch(
  55             iwp->ioc, G_IO_IN | G_IO_ERR | G_IO_HUP | G_IO_NVAL);
  56         g_source_set_callback(iwp->src, iwp->fd_read, iwp->opaque, NULL);
  57         g_source_add_child_source(source, iwp->src);
  58         g_source_unref(iwp->src);
  59     } else {
  60         g_source_remove_child_source(source, iwp->src);
  61         iwp->src = NULL;
  62     }
  63     return FALSE;
  64 }
  65
  66 static gboolean io_watch_poll_dispatch(GSource *source, GSourceFunc callback,
  67                                        gpointer user_data)
  68 {
  69     return G_SOURCE_CONTINUE;
  70 }
  71
  72 static GSourceFuncs io_watch_poll_funcs = {
  73     .prepare = io_watch_poll_prepare,
  74     .dispatch = io_watch_poll_dispatch,
  75 };
  76
  77 GSource *io_add_watch_poll(Chardev *chr,
  78                         QIOChannel *ioc,
  79                         IOCanReadHandler *fd_can_read,
  80                         QIOChannelFunc fd_read,
  81                         gpointer user_data,
  82                         GMainContext *context)
  83 {
  84     IOWatchPoll *iwp;
  85     char *name;
  86
  87     iwp = (IOWatchPoll *) g_source_new(&io_watch_poll_funcs,
  88                                        sizeof(IOWatchPoll));
  89     iwp->fd_can_read = fd_can_read;
  90     iwp->opaque = user_data;
  91     iwp->ioc = ioc;
  92     iwp->fd_read = (GSourceFunc) fd_read;
  93     iwp->src = NULL;
  94
  95     name = g_strdup_printf("chardev-iowatch-%s", chr->label);
  96     g_source_set_name((GSource *)iwp, name);
  97     g_free(name);
  98
  99     g_source_attach(&iwp->parent, context);
 100     g_source_unref(&iwp->parent);
 101     return (GSource *)iwp;
 102 }
 103
 104 void remove_fd_in_watch(Chardev *chr)
 105 {
 106     if (chr->gsource) {
 107         g_source_destroy(chr->gsource);
 108         chr->gsource = NULL;
 109     }
 110 }
 111
 112 int io_channel_send_full(QIOChannel *ioc,
 113                          const void *buf, size_t len,
 114                          int *fds, size_t nfds)
 115 {
 116     size_t offset = 0;
 117
 118     while (offset < len) {
 119         ssize_t ret = 0;
 120         struct iovec iov = { .iov_base = (char *)buf + offset,
 121                              .iov_len = len - offset };
 122
 123         ret = qio_channel_writev_full(
 124             ioc, &iov, 1,
 125             fds, nfds, 0, NULL);
 126         if (ret == QIO_CHANNEL_ERR_BLOCK) {
 127             if (offset) {
 128                 return offset;
 129             }
 130
 131             errno = EAGAIN;
 132             return -1;
 133         } else if (ret < 0) {
 134             errno = EINVAL;
 135             return -1;
 136         }
 137
 138         offset += ret;
 139     }
 140
 141     return offset;
 142 }
 143
 144 int io_channel_send(QIOChannel *ioc, const void *buf, size_t len)
 145 {
 146     return io_channel_send_full(ioc, buf, len, NULL, 0);
 147 }