The upcoming 'fixed-ram' feature would require qemu to write data at specific offsets of the file. This is currently missing so this patch adds it. I've chosen to implement it as a type-specific function rather than plumb it through the generic channel interface as it relies on being able to do seeks.
Signed-off-by: Nikolay Borisov <nbori...@suse.com> --- include/io/channel-file.h | 5 +++++ io/channel-file.c | 24 ++++++++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/include/io/channel-file.h b/include/io/channel-file.h index 50e8eb113868..0a5d54f5e58e 100644 --- a/include/io/channel-file.h +++ b/include/io/channel-file.h @@ -89,4 +89,9 @@ qio_channel_file_new_path(const char *path, mode_t mode, Error **errp); +ssize_t qio_channel_file_pwritev(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp); #endif /* QIO_CHANNEL_FILE_H */ diff --git a/io/channel-file.c b/io/channel-file.c index b67687c2aa64..da17d0a11ba7 100644 --- a/io/channel-file.c +++ b/io/channel-file.c @@ -136,6 +136,30 @@ static ssize_t qio_channel_file_writev(QIOChannel *ioc, return ret; } +ssize_t qio_channel_file_pwritev(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp) +{ + QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc); + ssize_t ret; + + retry: + ret = pwritev(fioc->fd, iov, niov, offset); + if (ret <= 0) { + if (errno == EAGAIN) { + return QIO_CHANNEL_ERR_BLOCK; + } + if (errno == EINTR) { + goto retry; + } + error_setg_errno(errp, errno, "Unable to write to file"); + return -1; + } + return ret; +} + static int qio_channel_file_set_blocking(QIOChannel *ioc, bool enabled, Error **errp) -- 2.34.1