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 "io/channel-file.h"
  22 #include "io/channel-watch.h"
  23 #include "qemu/sockets.h"
  24 #include "trace.h"
  25
  26 QIOChannelFile *
  27 qio_channel_file_new_fd(int fd)
  28 {
  29     QIOChannelFile *ioc;
  30
  31     ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
  32
  33     ioc->fd = fd;
  34
  35     trace_qio_channel_file_new_fd(ioc, fd);
  36
  37     return ioc;
  38 }
  39
  40
  41 QIOChannelFile *
  42 qio_channel_file_new_path(const char *path,
  43                           int flags,
  44                           mode_t mode,
  45                           Error **errp)
  46 {
  47     QIOChannelFile *ioc;
  48
  49     ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
  50
  51     if (flags & O_WRONLY) {
  52         ioc->fd = open(path, flags, mode);
  53     } else {
  54         ioc->fd = open(path, flags);
  55     }
  56     if (ioc->fd < 0) {
  57         object_unref(OBJECT(ioc));
  58         error_setg_errno(errp, errno,
  59                          "Unable to open %s", path);
  60         return NULL;
  61     }
  62
  63     trace_qio_channel_file_new_path(ioc, path, flags, mode, ioc->fd);
  64
  65     return ioc;
  66 }
  67
  68
  69 static void qio_channel_file_init(Object *obj)
  70 {
  71     QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
  72     ioc->fd = -1;
  73 }
  74
  75 static void qio_channel_file_finalize(Object *obj)
  76 {
  77     QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
  78     if (ioc->fd != -1) {
  79         close(ioc->fd);
  80         ioc->fd = -1;
  81     }
  82 }
  83
  84
  85 static ssize_t qio_channel_file_readv(QIOChannel *ioc,
  86                                       const struct iovec *iov,
  87                                       size_t niov,
  88                                       int **fds,
  89                                       size_t *nfds,
  90                                       Error **errp)
  91 {
  92     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
  93     ssize_t ret;
  94
  95  retry:
  96     ret = readv(fioc->fd, iov, niov);
  97     if (ret < 0) {
  98         if (errno == EAGAIN ||
  99             errno == EWOULDBLOCK) {
 100             return QIO_CHANNEL_ERR_BLOCK;
 101         }
 102         if (errno == EINTR) {
 103             goto retry;
 104         }
 105
 106         error_setg_errno(errp, errno,
 107                          "Unable to read from file");
 108         return -1;
 109     }
 110
 111     return ret;
 112 }
 113
 114 static ssize_t qio_channel_file_writev(QIOChannel *ioc,
 115                                        const struct iovec *iov,
 116                                        size_t niov,
 117                                        int *fds,
 118                                        size_t nfds,
 119                                        Error **errp)
 120 {
 121     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 122     ssize_t ret;
 123
 124  retry:
 125     ret = writev(fioc->fd, iov, niov);
 126     if (ret <= 0) {
 127         if (errno == EAGAIN ||
 128             errno == EWOULDBLOCK) {
 129             return QIO_CHANNEL_ERR_BLOCK;
 130         }
 131         if (errno == EINTR) {
 132             goto retry;
 133         }
 134         error_setg_errno(errp, errno,
 135                          "Unable to write to file");
 136         return -1;
 137     }
 138     return ret;
 139 }
 140
 141 static int qio_channel_file_set_blocking(QIOChannel *ioc,
 142                                          bool enabled,
 143                                          Error **errp)
 144 {
 145     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 146
 147     if (enabled) {
 148         qemu_set_block(fioc->fd);
 149     } else {
 150         qemu_set_nonblock(fioc->fd);
 151     }
 152     return 0;
 153 }
 154
 155
 156 static off_t qio_channel_file_seek(QIOChannel *ioc,
 157                                    off_t offset,
 158                                    int whence,
 159                                    Error **errp)
 160 {
 161     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 162     off_t ret;
 163
 164     ret = lseek(fioc->fd, offset, whence);
 165     if (ret == (off_t)-1) {
 166         error_setg_errno(errp, errno,
 167                          "Unable to seek to offset %lld whence %d in file",
 168                          (long long int)offset, whence);
 169         return -1;
 170     }
 171     return ret;
 172 }
 173
 174
 175 static int qio_channel_file_close(QIOChannel *ioc,
 176                                   Error **errp)
 177 {
 178     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 179
 180     if (close(fioc->fd) < 0) {
 181         error_setg_errno(errp, errno,
 182                          "Unable to close file");
 183         return -1;
 184     }
 185     return 0;
 186 }
 187
 188
 189 static GSource *qio_channel_file_create_watch(QIOChannel *ioc,
 190                                               GIOCondition condition)
 191 {
 192     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 193     return qio_channel_create_fd_watch(ioc,
 194                                        fioc->fd,
 195                                        condition);
 196 }
 197
 198 static void qio_channel_file_class_init(ObjectClass *klass,
 199                                         void *class_data G_GNUC_UNUSED)
 200 {
 201     QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
 202
 203     ioc_klass->io_writev = qio_channel_file_writev;
 204     ioc_klass->io_readv = qio_channel_file_readv;
 205     ioc_klass->io_set_blocking = qio_channel_file_set_blocking;
 206     ioc_klass->io_seek = qio_channel_file_seek;
 207     ioc_klass->io_close = qio_channel_file_close;
 208     ioc_klass->io_create_watch = qio_channel_file_create_watch;
 209 }
 210
 211 static const TypeInfo qio_channel_file_info = {
 212     .parent = TYPE_QIO_CHANNEL,
 213     .name = TYPE_QIO_CHANNEL_FILE,
 214     .instance_size = sizeof(QIOChannelFile),
 215     .instance_init = qio_channel_file_init,
 216     .instance_finalize = qio_channel_file_finalize,
 217     .class_init = qio_channel_file_class_init,
 218 };
 219
 220 static void qio_channel_file_register_types(void)
 221 {
 222     type_register_static(&qio_channel_file_info);
 223 }
 224
 225 type_init(qio_channel_file_register_types);