[Qemu-devel] Re: [RFC][PATCH v6 08/23] virtagent: add va.getfile RPC

[Jes Sorensen <Jes.Sorensen@redhat.com>]

On 01/17/11 14:15, Michael Roth wrote:
> Add RPC to retrieve a guest file. This interface is intended
> for smaller reads like peeking at logs and /proc and such.
> 
> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
> ---
>  virtagent-server.c |   59 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 59 insertions(+), 0 deletions(-)
> 
> diff --git a/virtagent-server.c b/virtagent-server.c
> index c38a9e0..af4b940 100644
> --- a/virtagent-server.c
> +++ b/virtagent-server.c
> @@ -62,12 +62,71 @@ out:
>      return ret;
>  }
>  
> +/* RPC functions common to guest/host daemons */
> +
> +/* va_getfile(): return file contents
> + * rpc return values:
> + *   - base64-encoded file contents
> + */
> +static xmlrpc_value *va_getfile(xmlrpc_env *env,
> +                                xmlrpc_value *params,
> +                                void *user_data)
> +{
> +    const char *path;
> +    char *file_contents = NULL;
> +    char buf[VA_FILEBUF_LEN];

malloc()!

> +    int fd, ret, count = 0;
> +    xmlrpc_value *result = NULL;
> +
> +    /* parse argument array */
> +    xmlrpc_decompose_value(env, params, "(s)", &path);
> +    if (env->fault_occurred) {
> +        return NULL;
> +    }
> +
> +    SLOG("va_getfile(), path:%s", path);
> +
> +    fd = open(path, O_RDONLY);
> +    if (fd == -1) {
> +        LOG("open failed: %s", strerror(errno));
> +        xmlrpc_faultf(env, "open failed: %s", strerror(errno));
> +        return NULL;
> +    }
> +
> +    while ((ret = read(fd, buf, VA_FILEBUF_LEN)) > 0) {
> +        file_contents = qemu_realloc(file_contents, count + VA_FILEBUF_LEN);
> +        memcpy(file_contents + count, buf, ret);

Sorry, I brought this up before. This realloc() stuff is a disaster
waiting to happen. Please remove it from the patch series, until you
have an implementation that copies over a page of the time.

> +        count += ret;

Cheers,
Jes