io/channel-file.c

   1 /*
   2  * QEMU I/O channels files driver
   3  *
   4  * Copyright (c) 2015 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "io/channel-file.h"
  23 #include "io/channel-watch.h"
  24 #include "qapi/error.h"
  25 #include "qemu/sockets.h"
  26 #include "trace.h"
  27
  28 QIOChannelFile *
  29 qio_channel_file_new_fd(int fd)
  30 {
  31     QIOChannelFile *ioc;
  32
  33     ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
  34
  35     ioc->fd = fd;
  36
  37     trace_qio_channel_file_new_fd(ioc, fd);
  38
  39     return ioc;
  40 }
  41
  42
  43 QIOChannelFile *
  44 qio_channel_file_new_path(const char *path,
  45                           int flags,
  46                           mode_t mode,
  47                           Error **errp)
  48 {
  49     QIOChannelFile *ioc;
  50
  51     ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
  52
  53     ioc->fd = qemu_open(path, flags, mode);
  54     if (ioc->fd < 0) {
  55         object_unref(OBJECT(ioc));
  56         error_setg_errno(errp, errno,
  57                          "Unable to open %s", path);
  58         return NULL;
  59     }
  60
  61     trace_qio_channel_file_new_path(ioc, path, flags, mode, ioc->fd);
  62
  63     return ioc;
  64 }
  65
  66
  67 static void qio_channel_file_init(Object *obj)
  68 {
  69     QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
  70     ioc->fd = -1;
  71 }
  72
  73 static void qio_channel_file_finalize(Object *obj)
  74 {
  75     QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
  76     if (ioc->fd != -1) {
  77         qemu_close(ioc->fd);
  78         ioc->fd = -1;
  79     }
  80 }
  81
  82
  83 static ssize_t qio_channel_file_readv(QIOChannel *ioc,
  84                                       const struct iovec *iov,
  85                                       size_t niov,
  86                                       int **fds,
  87                                       size_t *nfds,
  88                                       Error **errp)
  89 {
  90     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
  91     ssize_t ret;
  92
  93  retry:
  94     ret = readv(fioc->fd, iov, niov);
  95     if (ret < 0) {
  96         if (errno == EAGAIN) {
  97             return QIO_CHANNEL_ERR_BLOCK;
  98         }
  99         if (errno == EINTR) {
 100             goto retry;
 101         }
 102
 103         error_setg_errno(errp, errno,
 104                          "Unable to read from file");
 105         return -1;
 106     }
 107
 108     return ret;
 109 }
 110
 111 static ssize_t qio_channel_file_writev(QIOChannel *ioc,
 112                                        const struct iovec *iov,
 113                                        size_t niov,
 114                                        int *fds,
 115                                        size_t nfds,
 116                                        Error **errp)
 117 {
 118     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 119     ssize_t ret;
 120
 121  retry:
 122     ret = writev(fioc->fd, iov, niov);
 123     if (ret <= 0) {
 124         if (errno == EAGAIN) {
 125             return QIO_CHANNEL_ERR_BLOCK;
 126         }
 127         if (errno == EINTR) {
 128             goto retry;
 129         }
 130         error_setg_errno(errp, errno,
 131                          "Unable to write to file");
 132         return -1;
 133     }
 134     return ret;
 135 }
 136
 137 static int qio_channel_file_set_blocking(QIOChannel *ioc,
 138                                          bool enabled,
 139                                          Error **errp)
 140 {
 141     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 142
 143     if (enabled) {
 144         qemu_set_block(fioc->fd);
 145     } else {
 146         qemu_set_nonblock(fioc->fd);
 147     }
 148     return 0;
 149 }
 150
 151
 152 static off_t qio_channel_file_seek(QIOChannel *ioc,
 153                                    off_t offset,
 154                                    int whence,
 155                                    Error **errp)
 156 {
 157     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 158     off_t ret;
 159
 160     ret = lseek(fioc->fd, offset, whence);
 161     if (ret == (off_t)-1) {
 162         error_setg_errno(errp, errno,
 163                          "Unable to seek to offset %lld whence %d in file",
 164                          (long long int)offset, whence);
 165         return -1;
 166     }
 167     return ret;
 168 }
 169
 170
 171 static int qio_channel_file_close(QIOChannel *ioc,
 172                                   Error **errp)
 173 {
 174     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 175
 176     if (qemu_close(fioc->fd) < 0) {
 177         error_setg_errno(errp, errno,
 178                          "Unable to close file");
 179         return -1;
 180     }
 181     fioc->fd = -1;
 182     return 0;
 183 }
 184
 185
 186 static void qio_channel_file_set_aio_fd_handler(QIOChannel *ioc,
 187                                                 AioContext *ctx,
 188                                                 IOHandler *io_read,
 189                                                 IOHandler *io_write,
 190                                                 void *opaque)
 191 {
 192     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 193     aio_set_fd_handler(ctx, fioc->fd, false, io_read, io_write, NULL, opaque);
 194 }
 195
 196 static GSource *qio_channel_file_create_watch(QIOChannel *ioc,
 197                                               GIOCondition condition)
 198 {
 199     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 200     return qio_channel_create_fd_watch(ioc,
 201                                        fioc->fd,
 202                                        condition);
 203 }
 204
 205 static void qio_channel_file_class_init(ObjectClass *klass,
 206                                         void *class_data G_GNUC_UNUSED)
 207 {
 208     QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
 209
 210     ioc_klass->io_writev = qio_channel_file_writev;
 211     ioc_klass->io_readv = qio_channel_file_readv;
 212     ioc_klass->io_set_blocking = qio_channel_file_set_blocking;
 213     ioc_klass->io_seek = qio_channel_file_seek;
 214     ioc_klass->io_close = qio_channel_file_close;
 215     ioc_klass->io_create_watch = qio_channel_file_create_watch;
 216     ioc_klass->io_set_aio_fd_handler = qio_channel_file_set_aio_fd_handler;
 217 }
 218
 219 static const TypeInfo qio_channel_file_info = {
 220     .parent = TYPE_QIO_CHANNEL,
 221     .name = TYPE_QIO_CHANNEL_FILE,
 222     .instance_size = sizeof(QIOChannelFile),
 223     .instance_init = qio_channel_file_init,
 224     .instance_finalize = qio_channel_file_finalize,
 225     .class_init = qio_channel_file_class_init,
 226 };
 227
 228 static void qio_channel_file_register_types(void)
 229 {
 230     type_register_static(&qio_channel_file_info);
 231 }
 232
 233 type_init(qio_channel_file_register_types);