Dan Smith wrote:
> Signed-off-by: Dan Smith <danms@xxxxxxxxxx>
> ---
> checkpoint/restart.c | 35 +++++++++++++++++++++++++++++++++++
> include/linux/checkpoint.h | 1 +
> 2 files changed, 36 insertions(+), 0 deletions(-)
>
> diff --git a/checkpoint/restart.c b/checkpoint/restart.c
> index 5cbe491..06fe47e 100644
> --- a/checkpoint/restart.c
> +++ b/checkpoint/restart.c
> @@ -339,6 +339,41 @@ int ckpt_read_consume(struct ckpt_ctx *ctx, int len, int type)
> return ret;
> }
>
> +/**
> + * ckpt_read_string - read a string (variable length)
> + * @ctx: checkpoint context
> + * @max: maximum acceptable length
> + * @str: pointer to buffer to store allocated string (caller must kfree())
> + *
> + * This can be used to read a variable-length string from the checkpoint
> + * stream. @max limits the size of the resulting buffer. Returns zero on
> + * success, negative on failure.
> + */
> +int ckpt_read_string(struct ckpt_ctx *ctx, char **str, int max)
> +{
> + struct ckpt_hdr *h;
> + char *buf;
> + int len;
> + int ret = 0;
> +
> + h = ckpt_read_buf_type(ctx, max, CKPT_HDR_STRING);
> + if (IS_ERR(h))
> + return PTR_ERR(h);
> +
> + buf = (char *)(h + 1);
> + len = h->len - sizeof(*h);
> +
> + *str = kzalloc(len + 1, GFP_KERNEL);
> + if (!*str)
> + ret = -ENOMEM;
> + else
> + memcpy(*str, buf, len);
> +
You can avoid the memcpy() if you first read only the header, allocate
the string, and then read data into it.
Given that you already want _ckpt_read_obj_data() (or _payload) that
reads certain @len into a given buffer, why not add ckpt_read_obj_data()
that will return an allocate payload buffer.
Something like ...
int _ckpt_read_obj_data(ctx, ptr, len)
{
return ckpt_kread(ctx, ptr, len);
}
void *ckpt_read_obj_data(ctx, len, type)
{
void *buf = NULL;
ret = _ckpt_read_obj_type(ctx, NULL, len, type);
if (ret < 0)
return ERR_PTR(ret);
if (len && ret != len)
return ERR_PTR(-EINVAL);
if (ret) {
buf = kzalloc(len, GFP_KERNEL);
if (!buf)
return ERR_PTR(-ENOMEM);
ret = _ckpt_read_obj_data(ctx, buf, ret);
if (ret < 0) {
kfree(buf);
buf = ERR_PTR(ret);
}
}
return buf;
}
On top of this you can have ckpt_read_string() that will verify that
the buffer is of non-zero length and null terminated ?
Oren.
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