On 08/24/2017 07:23 AM, Erik Skultety wrote:
> Since we have a number of places where we workaround timing issues with
> devices, attributes (files in general) not being available at the time
> of processing them by calling usleep in a loop for a fixed number of
> tries, we could as well have a utility function that would do that.
> Therefore we won't have to duplicate this ugly workaround even more.
>
> Signed-off-by: Erik Skultety <eskultet@xxxxxxxxxx>
> ---
> src/libvirt_private.syms | 1 +
> src/util/virfile.c | 29 +++++++++++++++++++++++++++++
> src/util/virfile.h | 2 ++
> 3 files changed, 32 insertions(+)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 2149b11b7..b9fb54a79 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1724,6 +1724,7 @@ virFileStripSuffix;
> virFileTouch;
> virFileUnlock;
> virFileUpdatePerm;
> +virFileWaitForAccess;
> virFileWrapperFdClose;
> virFileWrapperFdFree;
> virFileWrapperFdNew;
> diff --git a/src/util/virfile.c b/src/util/virfile.c
> index 2f28e83f4..15b46bcdd 100644
> --- a/src/util/virfile.c
> +++ b/src/util/virfile.c
> @@ -4166,3 +4166,32 @@ virFileReadValueString(char **value, const char *format, ...)
> VIR_FREE(str);
> return ret;
> }
> +
> +
> +/**
> + * virFileWaitForAccess:
> + * @path: absolute path to a sysfs attribute (can be a symlink)
> + * @ms: how long to wait (in milliseconds)
> + * @tries: how many times should we try to wait for @path to become accessible
> + *
> + * Checks the existence of @path. In case the file defined by @path
> + * doesn't exist, we wait for it to appear in @ms milliseconds (for up to
> + * @tries attempts).
> + *
> + * Returns 0 on success, -1 on error, setting errno appropriately.
> + */
> +int
> +virFileWaitForAccess(const char *path, size_t ms, size_t tries)
Multiple lines per argument
NIT: WaitForExists()
John
> +{
> + errno = 0;
> +
> + /* wait for @path to be accessible in @ms milliseconds, up to @tries */
> + while (tries-- > 0 && !virFileExists(path)) {
> + if (tries == 0 || errno != ENOENT)
> + return -1;
> +
> + usleep(ms * 1000);
> + }
> +
> + return 0;
> +}
> diff --git a/src/util/virfile.h b/src/util/virfile.h
> index 57ceb8072..42630ebb5 100644
> --- a/src/util/virfile.h
> +++ b/src/util/virfile.h
> @@ -347,6 +347,8 @@ int virFileReadValueScaledInt(unsigned long long *value, const char *format, ...
> int virFileReadValueString(char **value, const char *format, ...)
> ATTRIBUTE_FMT_PRINTF(2, 3);
>
> +int virFileWaitForAccess(const char *path, size_t ms, size_t tries);
> +
>
> int virFileInData(int fd,
> int *inData,
>
--
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