[PATCH v2 3/4] block: detect DKIOCGETBLOCKCOUNT/SIZE before use

Joelle van Dyne posted 4 patches 4 years, 8 months ago
Maintainers: Jason Wang <jasowang@redhat.com>, Samuel Thibault <samuel.thibault@ens-lyon.org>, Max Reitz <mreitz@redhat.com>, Kevin Wolf <kwolf@redhat.com>, Markus Armbruster <armbru@redhat.com>, Eric Blake <eblake@redhat.com>
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[PATCH v2 3/4] block: detect DKIOCGETBLOCKCOUNT/SIZE before use
Posted by Joelle van Dyne 4 years, 8 months ago
iOS hosts do not have these defined so we fallback to the
default behaviour.

Co-authored-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Joelle van Dyne <j@getutm.app>
---
 block/file-posix.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index d1ab3180ff..9b6d7ddda3 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2326,8 +2326,10 @@ static int64_t raw_getlength(BlockDriverState *bs)
 again:
 #endif
     if (!fstat(fd, &sb) && (S_IFCHR & sb.st_mode)) {
+        size = 0;
 #ifdef DIOCGMEDIASIZE
         if (ioctl(fd, DIOCGMEDIASIZE, (off_t *)&size))
+            size = 0;
 #elif defined(DIOCGPART)
         {
                 struct partinfo pi;
@@ -2336,9 +2338,7 @@ again:
                 else
                         size = 0;
         }
-        if (size == 0)
-#endif
-#if defined(__APPLE__) && defined(__MACH__)
+#elif defined(DKIOCGETBLOCKCOUNT) && defined(DKIOCGETBLOCKSIZE)
         {
             uint64_t sectors = 0;
             uint32_t sector_size = 0;
@@ -2346,19 +2346,15 @@ again:
             if (ioctl(fd, DKIOCGETBLOCKCOUNT, &sectors) == 0
                && ioctl(fd, DKIOCGETBLOCKSIZE, &sector_size) == 0) {
                 size = sectors * sector_size;
-            } else {
-                size = lseek(fd, 0LL, SEEK_END);
-                if (size < 0) {
-                    return -errno;
-                }
             }
         }
-#else
-        size = lseek(fd, 0LL, SEEK_END);
+#endif
+        if (size == 0) {
+            size = lseek(fd, 0LL, SEEK_END);
+        }
         if (size < 0) {
             return -errno;
         }
-#endif
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
         switch(s->type) {
         case FTYPE_CD:
-- 
2.28.0


Re: [PATCH v2 3/4] block: detect DKIOCGETBLOCKCOUNT/SIZE before use
Posted by Peter Maydell 4 years, 8 months ago
On Tue, 9 Mar 2021 at 00:30, Joelle van Dyne <j@getutm.app> wrote:
>
> iOS hosts do not have these defined so we fallback to the
> default behaviour.
>
> Co-authored-by: Warner Losh <imp@bsdimp.com>
> Signed-off-by: Joelle van Dyne <j@getutm.app>
> ---
>  block/file-posix.c | 18 +++++++-----------
>  1 file changed, 7 insertions(+), 11 deletions(-)

raw_getlength() is a bit of a mess; this certainly seems like
an improvement...

> diff --git a/block/file-posix.c b/block/file-posix.c
> index d1ab3180ff..9b6d7ddda3 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -2326,8 +2326,10 @@ static int64_t raw_getlength(BlockDriverState *bs)
>  again:
>  #endif
>      if (!fstat(fd, &sb) && (S_IFCHR & sb.st_mode)) {
> +        size = 0;
>  #ifdef DIOCGMEDIASIZE
>          if (ioctl(fd, DIOCGMEDIASIZE, (off_t *)&size))
> +            size = 0;

this if() should have braces {}.

Otherwise
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM