Re: [Qemu-devel] [PATCH v4 06/47] Add qemu_get_counted_string to read a string prefixed by a count byte

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Oct 03, 2014 at 06:47:12PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> and use it in loadvm_state.
> 
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  include/migration/qemu-file.h |  2 ++
>  qemu-file.c                   | 15 +++++++++++++++
>  savevm.c                      | 18 ++++++++++--------
>  3 files changed, 27 insertions(+), 8 deletions(-)
> 
> diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
> index 6ef8ebc..a8cac7a 100644
> --- a/include/migration/qemu-file.h
> +++ b/include/migration/qemu-file.h
> @@ -300,4 +300,6 @@ static inline void qemu_get_sbe64s(QEMUFile *f, int64_t *pv)
>  {
>      qemu_get_be64s(f, (uint64_t *)pv);
>  }
> +
> +int qemu_get_counted_string(QEMUFile *f, uint8_t *buf);

I'd suggest writing the prototype as

int qemu_get_counted_string(QEMUFile *f, uint8_t buf[256]);

The compiled code will be identical, of course, but it helps to
document what the function expects.


>  #endif
> diff --git a/qemu-file.c b/qemu-file.c
> index ccc516c..a057b3e 100644
> --- a/qemu-file.c
> +++ b/qemu-file.c
> @@ -879,6 +879,21 @@ uint64_t qemu_get_be64(QEMUFile *f)
>      return v;
>  }
>  
> +/*
> + * Get a string whose length is determined by a single preceding byte
> + * A preallocated 256 byte buffer must be passed in.
> + * Returns: 0 on success and a 0 terminated string in the buffer
> + */
> +int qemu_get_counted_string(QEMUFile *f, uint8_t *buf)
> +{
> +    unsigned int len = qemu_get_byte(f);
> +    int res = qemu_get_buffer(f, buf, len);
> +
> +    buf[len] = 0;
> +
> +    return res != len;
> +}
> +
>  #define QSB_CHUNK_SIZE      (1 << 10)
>  #define QSB_MAX_CHUNK_SIZE  (16 * QSB_CHUNK_SIZE)
>  
> diff --git a/savevm.c b/savevm.c
> index c3a1f68..cb6f0de 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -908,7 +908,7 @@ int qemu_loadvm_state(QEMUFile *f)
>  
>      v = qemu_get_be32(f);
>      if (v == QEMU_VM_FILE_VERSION_COMPAT) {
> -        fprintf(stderr, "SaveVM v2 format is obsolete and don't work anymore\n");
> +        error_report("SaveVM v2 format is obsolete and don't work anymore");

These changes of fprintf() to error_report() look like an unrelated
cleanup.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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