/* $Id: ares_data.c,v 1.2 2009-11-20 09:06:33 yangtse Exp $ */ /* Copyright (C) 2009 by Daniel Stenberg * * Permission to use, copy, modify, and distribute this * software and its documentation for any purpose and without * fee is hereby granted, provided that the above copyright * notice appear in all copies and that both that copyright * notice and this permission notice appear in supporting * documentation, and that the name of M.I.T. not be used in * advertising or publicity pertaining to distribution of the * software without specific, written prior permission. * M.I.T. makes no representations about the suitability of * this software for any purpose. It is provided "as is" * without express or implied warranty. */ #include "ares_setup.h" #include <stddef.h> #include "ares.h" #include "ares_data.h" #include "ares_private.h" /* ** ares_free_data() - c-ares external API function. ** ** This function must be used by the application to free data memory that ** has been internally allocated by some c-ares function and for which a ** pointer has already been returned to the calling application. The list ** of c-ares functions returning pointers that must be free'ed using this ** function is: ** ** ares_parse_srv_reply() ** ares_parse_txt_reply() */ void ares_free_data(void *dataptr) { struct ares_data *ptr; if (!dataptr) return; ptr = (void *)((char *)dataptr - offsetof(struct ares_data, data)); if (ptr->mark != ARES_DATATYPE_MARK) return; switch (ptr->type) { case ARES_DATATYPE_SRV_REPLY: if (ptr->data.srv_reply.next) ares_free_data(ptr->data.srv_reply.next); if (ptr->data.srv_reply.host) free(ptr->data.srv_reply.host); break; case ARES_DATATYPE_TXT_REPLY: if (ptr->data.txt_reply.next) ares_free_data(ptr->data.txt_reply.next); if (ptr->data.txt_reply.txt) free(ptr->data.txt_reply.txt); break; default: return; } free(ptr); } /* ** ares_malloc_data() - c-ares internal helper function. ** ** This function allocates memory for a c-ares private ares_data struct ** for the specified ares_datatype, initializes c-ares private fields ** and zero initializes those which later might be used from the public ** API. It returns an interior pointer which can be passed by c-ares ** functions to the calling application, and that must be free'ed using ** c-ares external API function ares_free_data(). */ void *ares_malloc_data(ares_datatype type) { struct ares_data *ptr; ptr = malloc(sizeof(struct ares_data)); if (!ptr) return NULL; switch (type) { case ARES_DATATYPE_SRV_REPLY: ptr->data.srv_reply.next = NULL; ptr->data.srv_reply.host = NULL; ptr->data.srv_reply.priority = 0; ptr->data.srv_reply.weight = 0; ptr->data.srv_reply.port = 0; break; case ARES_DATATYPE_TXT_REPLY: ptr->data.txt_reply.next = NULL; ptr->data.txt_reply.txt = NULL; ptr->data.txt_reply.length = 0; break; default: free(ptr); return NULL; } ptr->mark = ARES_DATATYPE_MARK; ptr->type = type; return &ptr->data; } /* ** ares_get_datatype() - c-ares internal helper function. ** ** This function returns the ares_datatype of the data stored in a ** private ares_data struct when given the public API pointer. */ ares_datatype ares_get_datatype(void * dataptr) { struct ares_data *ptr; ptr = (void *)((char *)dataptr - offsetof(struct ares_data, data)); if (ptr->mark == ARES_DATATYPE_MARK) return ptr->type; return ARES_DATATYPE_UNKNOWN; }