Re: [Qemu-devel] [PATCH v3] virtio-9p: fix build on !CONFIG_UTIMENSAT

[Anthony Liguori]

On 11/14/2010 08:15 PM, Hidetoshi Seto wrote:
> This patch introduce a fallback mechanism for old systems that do not
> support utimensat().  This fix build failure with following warnings:
>
> hw/virtio-9p-local.c: In function 'local_utimensat':
> hw/virtio-9p-local.c:479: warning: implicit declaration of function 'utimensat'
> hw/virtio-9p-local.c:479: warning: nested extern declaration of 'utimensat'
>
> and:
>
> hw/virtio-9p.c: In function 'v9fs_setattr_post_chmod':
> hw/virtio-9p.c:1410: error: 'UTIME_NOW' undeclared (first use in this function)
> hw/virtio-9p.c:1410: error: (Each undeclared identifier is reported only once
> hw/virtio-9p.c:1410: error: for each function it appears in.)
> hw/virtio-9p.c:1413: error: 'UTIME_OMIT' undeclared (first use in this function)
> hw/virtio-9p.c: In function 'v9fs_wstat_post_chmod':
> hw/virtio-9p.c:2905: error: 'UTIME_OMIT' undeclared (first use in this function)
>
> v3:
>    - Use better alternative handling for UTIME_NOW/OMIT
>    - Move qemu_utimensat() to cutils.c
> V2:
>    - Introduce qemu_utimensat()
>
> Signed-off-by: Hidetoshi Seto<address@hidden>
>    

Applied.  Thanks.

Regards,

Anthony Liguori

> ---
>   cutils.c             |   43 +++++++++++++++++++++++++++++++++++++++++++
>   hw/virtio-9p-local.c |    4 ++--
>   qemu-common.h        |   10 ++++++++++
>   3 files changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/cutils.c b/cutils.c
> index 536ee93..3c18941 100644
> --- a/cutils.c
> +++ b/cutils.c
> @@ -288,3 +288,46 @@ int fcntl_setfl(int fd, int flag)
>   }
>   #endif
>
> +int qemu_utimensat(int dirfd, const char *path, const struct timespec *times,
> +                   int flags)
> +{
> +#ifdef CONFIG_UTIMENSAT
> +    return utimensat(dirfd, path, times, flags);
> +#else
> +    /* Fallback: use utimes() instead of utimensat() */
> +    struct timeval tv[2], tv_now;
> +    struct stat st;
> +    int i;
> +
> +    /* happy if special cases */
> +    if (times[0].tv_nsec == UTIME_OMIT&&  times[1].tv_nsec == UTIME_OMIT) {
> +        return 0;
> +    }
> +    if (times[0].tv_nsec == UTIME_NOW&&  times[1].tv_nsec == UTIME_NOW) {
> +        return utimes(path, NULL);
> +    }
> +
> +    /* prepare for hard cases */
> +    if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
> +        gettimeofday(&tv_now, NULL);
> +    }
> +    if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
> +        stat(path,&st);
> +    }
> +
> +    for (i = 0; i<  2; i++) {
> +        if (times[i].tv_nsec == UTIME_NOW) {
> +            tv[i].tv_sec = tv_now.tv_sec;
> +            tv[i].tv_usec = 0;
> +        } else if (times[i].tv_nsec == UTIME_OMIT) {
> +            tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
> +            tv[i].tv_usec = 0;
> +        } else {
> +            tv[i].tv_sec = times[i].tv_sec;
> +            tv[i].tv_usec = times[i].tv_nsec / 1000;
> +        }
> +    }
> +
> +    return utimes(path,&tv[0]);
> +#endif
> +}
> diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c
> index 0d52020..41603ea 100644
> --- a/hw/virtio-9p-local.c
> +++ b/hw/virtio-9p-local.c
> @@ -480,9 +480,9 @@ static int local_chown(FsContext *fs_ctx, const char *path, 
> FsCred *credp)
>   }
>
>   static int local_utimensat(FsContext *s, const char *path,
> -                      const struct timespec *buf)
> +                           const struct timespec *buf)
>   {
> -    return utimensat(AT_FDCWD, rpath(s, path), buf, AT_SYMLINK_NOFOLLOW);
> +    return qemu_utimensat(AT_FDCWD, rpath(s, path), buf, AT_SYMLINK_NOFOLLOW);
>   }
>
>   static int local_remove(FsContext *ctx, const char *path)
> diff --git a/qemu-common.h b/qemu-common.h
> index 2fbc27f..7fe4c16 100644
> --- a/qemu-common.h
> +++ b/qemu-common.h
> @@ -146,6 +146,16 @@ time_t mktimegm(struct tm *tm);
>   int qemu_fls(int i);
>   int qemu_fdatasync(int fd);
>   int fcntl_setfl(int fd, int flag);
> +#ifndef CONFIG_UTIMENSAT
> +#ifndef UTIME_NOW
> +# define UTIME_NOW     ((1l<<  30) - 1l)
> +#endif
> +#ifndef UTIME_OMIT
> +# define UTIME_OMIT    ((1l<<  30) - 2l)
> +#endif
> +#endif
> +int qemu_utimensat(int dirfd, const char *path, const struct timespec *times,
> +    int flags);
>
>   /* path.c */
>   void init_paths(const char *prefix);
>