On Fri, Oct 30, 2015 at 01:56:05PM +0800, Xiao Guangrong wrote:
> Use the whole file size if @size is not specified which is useful
> if we want to directly pass a file to guest
>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> ---
> backends/hostmem-file.c | 48 ++++++++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 44 insertions(+), 4 deletions(-)
>
> diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c
> index 9097a57..e1bc9ff 100644
> --- a/backends/hostmem-file.c
> +++ b/backends/hostmem-file.c
> @@ -9,6 +9,9 @@
> * This work is licensed under the terms of the GNU GPL, version 2 or later.
> * See the COPYING file in the top-level directory.
> */
> +#include <sys/ioctl.h>
> +#include <linux/fs.h>
This code needs to build on other platforms too. e.g. using mingw32:
CC backends/hostmem-file.o
/home/ehabkost/rh/proj/virt/qemu/backends/hostmem-file.c:12:23: fatal error: sys/ioctl.h: No such file or directory
#include <sys/ioctl.h>
^
compilation terminated.
/home/ehabkost/rh/proj/virt/qemu/rules.mak:57: recipe for target 'backends/hostmem-file.o' failed
make: *** [backends/hostmem-file.o] Error 1
> +
> #include "qemu-common.h"
> #include "sysemu/hostmem.h"
> #include "sysemu/sysemu.h"
> @@ -33,20 +36,57 @@ struct HostMemoryBackendFile {
> char *mem_path;
> };
>
> +static uint64_t get_file_size(const char *file)
> +{
> + struct stat stat_buf;
> + uint64_t size = 0;
> + int fd;
> +
> + fd = open(file, O_RDONLY);
> + if (fd < 0) {
> + return 0;
> + }
> +
> + if (stat(file, &stat_buf) < 0) {
> + goto exit;
> + }
> +
> + if ((S_ISBLK(stat_buf.st_mode)) && !ioctl(fd, BLKGETSIZE64, &size)) {
> + goto exit;
> + }
> +
> + size = lseek(fd, 0, SEEK_END);
> + if (size == -1) {
> + size = 0;
> + }
> +exit:
> + close(fd);
> + return size;
> +}
This code seems to duplicate what block/raw-posix.c:raw_getlength() does
(except for the BLKGETSIZE64 part). Have you considered using the same
code for both?
We can probably move all the raw-posix.c raw_getlength(BlockDriverState
*bs) code to fd_getlength(int fd) functions (on osdep.c?), and just
implement raw-posix.c:raw_getlength(s) as fd_getlength(s->fd).
> +
> static void
> file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
> {
> HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
>
> - if (!backend->size) {
> - error_setg(errp, "can't create backend with size 0");
> - return;
> - }
> if (!fb->mem_path) {
> error_setg(errp, "mem-path property not set");
> return;
> }
>
> + if (!backend->size) {
> + /*
> + * use the whole file size if @size is not specified.
> + */
> + backend->size = get_file_size(fb->mem_path);
> + }
> +
> + if (!backend->size) {
> + error_setg(errp, "failed to get file size for %s, can't create "
> + "backend on it", mem_path);
> + return;
> + }
> +
> backend->force_prealloc = mem_prealloc;
> memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),
> object_get_canonical_path(OBJECT(backend)),
> --
> 1.8.3.1
>
>
--
Eduardo
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