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. Mirek