Paolo Bonzini <pbonz...@redhat.com> writes:
> This uses system calls directly for Unix file descriptors, so that the
> efficient writev_buffer can be used. Pay attention to the possibility
> of partial writes in writev.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Needs rebasing:
CC i386-softmmu/savevm.o
/home/aliguori/git/qemu/savevm.c:439:5: error: initialization from incompatible
pointer type [-Werror]
/home/aliguori/git/qemu/savevm.c:439:5: error: (near initialization for
‘unix_write_ops.writev_buffer’) [-Werror]
cc1: all warnings being treated as errors
make[1]: *** [savevm.o] Error 1
make: *** [subdir-i386-softmmu] Error 2
d13ed415c0ab9f7cf29226022f8c24d1b8dc794d is the first bad commit
commit d13ed415c0ab9f7cf29226022f8c24d1b8dc794d
Author: Paolo Bonzini <pbonz...@redhat.com>
Date: Wed Mar 27 17:36:32 2013 +0100
qemu-file: do not use stdio for qemu_fdopen
Regards,
Anthony Liguori
> ---
> savevm.c | 100
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 89 insertions(+), 11 deletions(-)
>
> diff --git a/savevm.c b/savevm.c
> index 0415830..8eb5aab 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -356,9 +356,93 @@ static const QEMUFileOps stdio_file_write_ops = {
> .close = stdio_fclose
> };
>
> +static ssize_t unix_writev_buffer(void *opaque, struct iovec *iov, int
> iovcnt)
> +{
> + QEMUFileSocket *s = opaque;
> + ssize_t len, offset;
> + ssize_t size = iov_size(iov, iovcnt);
> + ssize_t total = 0;
> +
> + assert(iovcnt > 0);
> + offset = 0;
> + while (size > 0) {
> + /* Find the next start position; skip all full-sized vector elements
> */
> + while (offset >= iov[0].iov_len) {
> + offset -= iov[0].iov_len;
> + iov++, iovcnt--;
> + }
> +
> + /* skip `offset' bytes from the (now) first element, undo it on exit
> */
> + assert(iovcnt > 0);
> + iov[0].iov_base += offset;
> + iov[0].iov_len -= offset;
> +
> + do {
> + len = writev(s->fd, iov, iovcnt);
> + } while (len == -1 && errno == EINTR);
> + if (len == -1) {
> + return -errno;
> + }
> +
> + /* Undo the changes above */
> + iov[0].iov_base -= offset;
> + iov[0].iov_len += offset;
> +
> + /* Prepare for the next iteration */
> + offset += len;
> + total += len;
> + size -= len;
> + }
> +
> + return total;
> +}
> +
> +static int unix_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
> +{
> + QEMUFileSocket *s = opaque;
> + ssize_t len;
> +
> + for (;;) {
> + len = read(s->fd, buf, size);
> + if (len != -1) {
> + break;
> + }
> + if (errno == EAGAIN) {
> + yield_until_fd_readable(s->fd);
> + } else if (errno != EINTR) {
> + break;
> + }
> + }
> +
> + if (len == -1) {
> + len = -errno;
> + }
> + return len;
> +}
> +
> +static int unix_close(void *opaque)
> +{
> + QEMUFileSocket *s = opaque;
> + close(s->fd);
> + g_free(s);
> + return 0;
> +}
> +
> +static const QEMUFileOps unix_read_ops = {
> + .get_fd = socket_get_fd,
> + .get_buffer = unix_get_buffer,
> + .close = unix_close
> +};
> +
> +static const QEMUFileOps unix_write_ops = {
> + .get_fd = socket_get_fd,
> + .writev_buffer = unix_writev_buffer,
> + .close = unix_close
> +};
> +
> QEMUFile *qemu_fdopen(int fd, const char *mode)
> {
> - QEMUFileStdio *s;
> + QEMUFileSocket *s;
>
> if (mode == NULL ||
> (mode[0] != 'r' && mode[0] != 'w') ||
> @@ -367,21 +451,15 @@ QEMUFile *qemu_fdopen(int fd, const char *mode)
> return NULL;
> }
>
> - s = g_malloc0(sizeof(QEMUFileStdio));
> - s->stdio_file = fdopen(fd, mode);
> - if (!s->stdio_file)
> - goto fail;
> + s = g_malloc0(sizeof(QEMUFileSocket));
> + s->fd = fd;
>
> if(mode[0] == 'r') {
> - s->file = qemu_fopen_ops(s, &stdio_file_read_ops);
> + s->file = qemu_fopen_ops(s, &unix_read_ops);
> } else {
> - s->file = qemu_fopen_ops(s, &stdio_file_write_ops);
> + s->file = qemu_fopen_ops(s, &unix_write_ops);
> }
> return s->file;
> -
> -fail:
> - g_free(s);
> - return NULL;
> }
>
> static const QEMUFileOps socket_read_ops = {
> --
> 1.8.1.4
