diff options
| -rw-r--r-- | include/io/channel.h | 82 | ||||
| -rw-r--r-- | io/channel.c | 58 |
2 files changed, 140 insertions, 0 deletions
diff --git a/include/io/channel.h b/include/io/channel.h index fcb19fd672..7986c49c71 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -131,6 +131,16 @@ struct QIOChannelClass { Error **errp); /* Optional callbacks */ + ssize_t (*io_pwritev)(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp); + ssize_t (*io_preadv)(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp); int (*io_shutdown)(QIOChannel *ioc, QIOChannelShutdown how, Error **errp); @@ -530,6 +540,78 @@ int qio_channel_close(QIOChannel *ioc, Error **errp); /** + * qio_channel_pwritev + * @ioc: the channel object + * @iov: the array of memory regions to write data from + * @niov: the length of the @iov array + * @offset: offset in the channel where writes should begin + * @errp: pointer to a NULL-initialized error object + * + * Not all implementations will support this facility, so may report + * an error. To avoid errors, the caller may check for the feature + * flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method. + * + * Behaves as qio_channel_writev_full, apart from not supporting + * sending of file handles as well as beginning the write at the + * passed @offset + * + */ +ssize_t qio_channel_pwritev(QIOChannel *ioc, const struct iovec *iov, + size_t niov, off_t offset, Error **errp); + +/** + * qio_channel_pwrite + * @ioc: the channel object + * @buf: the memory region to write data into + * @buflen: the number of bytes to @buf + * @offset: offset in the channel where writes should begin + * @errp: pointer to a NULL-initialized error object + * + * Not all implementations will support this facility, so may report + * an error. To avoid errors, the caller may check for the feature + * flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method. + * + */ +ssize_t qio_channel_pwrite(QIOChannel *ioc, char *buf, size_t buflen, + off_t offset, Error **errp); + +/** + * qio_channel_preadv + * @ioc: the channel object + * @iov: the array of memory regions to read data into + * @niov: the length of the @iov array + * @offset: offset in the channel where writes should begin + * @errp: pointer to a NULL-initialized error object + * + * Not all implementations will support this facility, so may report + * an error. To avoid errors, the caller may check for the feature + * flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method. + * + * Behaves as qio_channel_readv_full, apart from not supporting + * receiving of file handles as well as beginning the read at the + * passed @offset + * + */ +ssize_t qio_channel_preadv(QIOChannel *ioc, const struct iovec *iov, + size_t niov, off_t offset, Error **errp); + +/** + * qio_channel_pread + * @ioc: the channel object + * @buf: the memory region to write data into + * @buflen: the number of bytes to @buf + * @offset: offset in the channel where writes should begin + * @errp: pointer to a NULL-initialized error object + * + * Not all implementations will support this facility, so may report + * an error. To avoid errors, the caller may check for the feature + * flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method. + * + */ +ssize_t qio_channel_pread(QIOChannel *ioc, char *buf, size_t buflen, + off_t offset, Error **errp); + +/** * qio_channel_shutdown: * @ioc: the channel object * @how: the direction to shutdown diff --git a/io/channel.c b/io/channel.c index 86c5834510..a1f12f8e90 100644 --- a/io/channel.c +++ b/io/channel.c @@ -454,6 +454,64 @@ GSource *qio_channel_add_watch_source(QIOChannel *ioc, } +ssize_t qio_channel_pwritev(QIOChannel *ioc, const struct iovec *iov, + size_t niov, off_t offset, Error **errp) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + if (!klass->io_pwritev) { + error_setg(errp, "Channel does not support pwritev"); + return -1; + } + + if (!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_SEEKABLE)) { + error_setg_errno(errp, EINVAL, "Requested channel is not seekable"); + return -1; + } + + return klass->io_pwritev(ioc, iov, niov, offset, errp); +} + +ssize_t qio_channel_pwrite(QIOChannel *ioc, char *buf, size_t buflen, + off_t offset, Error **errp) +{ + struct iovec iov = { + .iov_base = buf, + .iov_len = buflen + }; + + return qio_channel_pwritev(ioc, &iov, 1, offset, errp); +} + +ssize_t qio_channel_preadv(QIOChannel *ioc, const struct iovec *iov, + size_t niov, off_t offset, Error **errp) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + if (!klass->io_preadv) { + error_setg(errp, "Channel does not support preadv"); + return -1; + } + + if (!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_SEEKABLE)) { + error_setg_errno(errp, EINVAL, "Requested channel is not seekable"); + return -1; + } + + return klass->io_preadv(ioc, iov, niov, offset, errp); +} + +ssize_t qio_channel_pread(QIOChannel *ioc, char *buf, size_t buflen, + off_t offset, Error **errp) +{ + struct iovec iov = { + .iov_base = buf, + .iov_len = buflen + }; + + return qio_channel_preadv(ioc, &iov, 1, offset, errp); +} + int qio_channel_shutdown(QIOChannel *ioc, QIOChannelShutdown how, Error **errp) |