Miloslav Trmač <mitr@xxxxxxxxxx> wrote:
> Jim Meyering píše v Čt 22. 01. 2009 v 19:15 +0100:
>> > +static int
>> > +cowGetBackingStore(virConnectPtr conn,
>> > + char **res,
>> > + const unsigned char *buf,
>> > + size_t buf_size)
>> > +{
>> > + size_t len;
>> > +
>> > + *res = NULL;
>> > + if (buf_size < 4+4+1024)
>> > + return BACKING_STORE_INVALID;
>> > + if (buf[4+4] == '\0') /* cow_header_v2.backing_file[0] */
>> > + return BACKING_STORE_OK;
>> > +
>> > + len = 1024;
>> > + if (VIR_ALLOC_N(*res, len + 1) < 0) {
>> > + virStorageReportError(conn, VIR_ERR_NO_MEMORY, _("backing store path"));
>> > + return BACKING_STORE_ERROR;
>> > + }
>> > + memcpy(*res, buf + 4+4, len); /* cow_header_v2.backing_file */
>> > + (*res)[len] = '\0';
>> > + if (VIR_REALLOC_N(*res, strlen(*res) + 1) < 0) {
>>
>> Is this just-copied 1024-byte block of data guaranteed
>> not to contain any NUL bytes? Or maybe you just want that
>> NUL-terminated string?
> The 1024 bytes should contain a NUL-terminated string. This code
> ensures there is a trailing NUL, then resizes *res to only contain the
> first NUL-terminated string. We could avoid the realloc() by using
> strnlen() from gnulib.
Hi Mirek,
Thanks for clarifying the intent.
In that case, we can just use strndup:
*res = strndup (buf + 4+4, len);
if (*res == NULL) {
virStorageReportError(conn, VIR_ERR_NO_MEMORY,
_("backing store path"));
return BACKING_STORE_ERROR;
}
--
Libvir-list mailing list
Libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list