Re: [Qemu-devel] [PATCH for-4.0 v4 2/4] refactor load_image_size

[Michael S. Tsirkin]

On Thu, Dec 06, 2018 at 10:32:11AM +0800, Li Zhijian wrote:
> Don't expect read(2) can always read as many as it's told.
> 
> Signed-off-by: Li Zhijian <address@hidden>
> Reviewed-by: Richard Henderson <address@hidden>

This is more a theoretical bugfix than a refactoring right?

> ---
> V4: add reviewed-by tag
> ---
>  hw/core/loader.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/core/loader.c b/hw/core/loader.c
> index fa41842..9cbceab 100644
> --- a/hw/core/loader.c
> +++ b/hw/core/loader.c
> @@ -77,21 +77,20 @@ int64_t get_image_size(const char *filename)
>  ssize_t load_image_size(const char *filename, void *addr, size_t size)
>  {
>      int fd;
> -    ssize_t actsize;
> +    ssize_t actsize, l = 0;
>  
>      fd = open(filename, O_RDONLY | O_BINARY);
>      if (fd < 0) {
>          return -1;
>      }
>  
> -    actsize = read(fd, addr, size);
> -    if (actsize < 0) {
> -        close(fd);
> -        return -1;
> +    while ((actsize = read(fd, addr + l, size - l)) > 0) {
> +        l += actsize;
>      }
> +
>      close(fd);
>  
> -    return actsize;
> +    return actsize < 0 ? -1 : l;
>  }
>  
>  /* read()-like version */
> -- 
> 2.7.4