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 2.1 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/module.h"
  26 #include "qemu/sockets.h"
  27 #include "trace.h"
  28
  29 QIOChannelFile *
  30 qio_channel_file_new_fd(int fd)
  31 {
  32     QIOChannelFile *ioc;
  33
  34     ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
  35
  36     ioc->fd = fd;
  37
  38     trace_qio_channel_file_new_fd(ioc, fd);
  39
  40     return ioc;
  41 }
  42
  43
  44 QIOChannelFile *
  45 qio_channel_file_new_path(const char *path,
  46                           int flags,
  47                           mode_t mode,
  48                           Error **errp)
  49 {
  50     QIOChannelFile *ioc;
  51
  52     ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
  53
  54     ioc->fd = qemu_open_old(path, flags, mode);
  55     if (ioc->fd < 0) {
  56         object_unref(OBJECT(ioc));
  57         error_setg_errno(errp, errno,
  58                          "Unable to open %s", path);
  59         return NULL;
  60     }
  61
  62     trace_qio_channel_file_new_path(ioc, path, flags, mode, ioc->fd);
  63
  64     return ioc;
  65 }
  66
  67
  68 static void qio_channel_file_init(Object *obj)
  69 {
  70     QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
  71     ioc->fd = -1;
  72 }
  73
  74 static void qio_channel_file_finalize(Object *obj)
  75 {
  76     QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
  77     if (ioc->fd != -1) {
  78         qemu_close(ioc->fd);
  79         ioc->fd = -1;
  80     }
  81 }
  82
  83
  84 static ssize_t qio_channel_file_readv(QIOChannel *ioc,
  85                                       const struct iovec *iov,
  86                                       size_t niov,
  87                                       int **fds,
  88                                       size_t *nfds,
  89                                       Error **errp)
  90 {
  91     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
  92     ssize_t ret;
  93
  94  retry:
  95     ret = readv(fioc->fd, iov, niov);
  96     if (ret < 0) {
  97         if (errno == EAGAIN) {
  98             return QIO_CHANNEL_ERR_BLOCK;
  99         }
 100         if (errno == EINTR) {
 101             goto retry;
 102         }
 103
 104         error_setg_errno(errp, errno,
 105                          "Unable to read from file");
 106         return -1;
 107     }
 108
 109     return ret;
 110 }
 111
 112 static ssize_t qio_channel_file_writev(QIOChannel *ioc,
 113                                        const struct iovec *iov,
 114                                        size_t niov,
 115                                        int *fds,
 116                                        size_t nfds,
 117                                        Error **errp)
 118 {
 119     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 120     ssize_t ret;
 121
 122  retry:
 123     ret = writev(fioc->fd, iov, niov);
 124     if (ret <= 0) {
 125         if (errno == EAGAIN) {
 126             return QIO_CHANNEL_ERR_BLOCK;
 127         }
 128         if (errno == EINTR) {
 129             goto retry;
 130         }
 131         error_setg_errno(errp, errno,
 132                          "Unable to write to file");
 133         return -1;
 134     }
 135     return ret;
 136 }
 137
 138 static int qio_channel_file_set_blocking(QIOChannel *ioc,
 139                                          bool enabled,
 140                                          Error **errp)
 141 {
 142     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 143
 144     if (enabled) {
 145         qemu_set_block(fioc->fd);
 146     } else {
 147         qemu_set_nonblock(fioc->fd);
 148     }
 149     return 0;
 150 }
 151
 152
 153 static off_t qio_channel_file_seek(QIOChannel *ioc,
 154                                    off_t offset,
 155                                    int whence,
 156                                    Error **errp)
 157 {
 158     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 159     off_t ret;
 160
 161     ret = lseek(fioc->fd, offset, whence);
 162     if (ret == (off_t)-1) {
 163         error_setg_errno(errp, errno,
 164                          "Unable to seek to offset %lld whence %d in file",
 165                          (long long int)offset, whence);
 166         return -1;
 167     }
 168     return ret;
 169 }
 170
 171
 172 static int qio_channel_file_close(QIOChannel *ioc,
 173                                   Error **errp)
 174 {
 175     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 176
 177     if (qemu_close(fioc->fd) < 0) {
 178         error_setg_errno(errp, errno,
 179                          "Unable to close file");
 180         return -1;
 181     }
 182     fioc->fd = -1;
 183     return 0;
 184 }
 185
 186
 187 static void qio_channel_file_set_aio_fd_handler(QIOChannel *ioc,
 188                                                 AioContext *ctx,
 189                                                 IOHandler *io_read,
 190                                                 IOHandler *io_write,
 191                                                 void *opaque)
 192 {
 193     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 194     aio_set_fd_handler(ctx, fioc->fd, false, io_read, io_write, NULL, opaque);
 195 }
 196
 197 static GSource *qio_channel_file_create_watch(QIOChannel *ioc,
 198                                               GIOCondition condition)
 199 {
 200     QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
 201     return qio_channel_create_fd_watch(ioc,
 202                                        fioc->fd,
 203                                        condition);
 204 }
 205
 206 static void qio_channel_file_class_init(ObjectClass *klass,
 207                                         void *class_data G_GNUC_UNUSED)
 208 {
 209     QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
 210
 211     ioc_klass->io_writev = qio_channel_file_writev;
 212     ioc_klass->io_readv = qio_channel_file_readv;
 213     ioc_klass->io_set_blocking = qio_channel_file_set_blocking;
 214     ioc_klass->io_seek = qio_channel_file_seek;
 215     ioc_klass->io_close = qio_channel_file_close;
 216     ioc_klass->io_create_watch = qio_channel_file_create_watch;
 217     ioc_klass->io_set_aio_fd_handler = qio_channel_file_set_aio_fd_handler;
 218 }
 219
 220 static const TypeInfo qio_channel_file_info = {
 221     .parent = TYPE_QIO_CHANNEL,
 222     .name = TYPE_QIO_CHANNEL_FILE,
 223     .instance_size = sizeof(QIOChannelFile),
 224     .instance_init = qio_channel_file_init,
 225     .instance_finalize = qio_channel_file_finalize,
 226     .class_init = qio_channel_file_class_init,
 227 };
 228
 229 static void qio_channel_file_register_types(void)
 230 {
 231     type_register_static(&qio_channel_file_info);
 232 }
 233
 234 type_init(qio_channel_file_register_types);