Commit 5a0a473c authored by Yang Tse's avatar Yang Tse
Browse files

Initial support for the generic ares_free_data() function that will allow 

applications to free memory allocated and returned by some c-ares funtions.
parent 5129442e

ares/Makefile.inc

+2 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ CSOURCES = ares__close_sockets.c \ 
  ares__read_line.c			\

  ares__timeval.c			\

  ares_cancel.c				\

  ares_data.c				\

  ares_destroy.c			\

  ares_expand_name.c			\

  ares_expand_string.c			\
@@ -41,6 +42,7 @@ CSOURCES = ares__close_sockets.c \ 


HHEADERS = ares.h			\

  ares_build.h				\

  ares_data.h				\

  ares_dns.h				\

  ares_ipv6.h				\

  ares_library_init.h			\

ares/ares.h

+10 −6
Original line number Diff line number Diff line
@@ -430,15 +430,17 @@ struct addr6ttl { 
};



struct ares_srv_reply {

  unsigned short weight;

  struct ares_srv_reply  *next;

  char                   *host;

  unsigned short          priority;

  unsigned short          weight;

  unsigned short          port;

  char *host;

};



struct ares_txt_reply {

  size_t         length;  /* length excludes null termination */

  struct ares_txt_reply  *next;

  unsigned char          *txt;

  size_t                  length;  /* length excludes null termination */

};



/*
@@ -486,6 +488,8 @@ CARES_EXTERN void ares_free_string(void *str); 


CARES_EXTERN void ares_free_hostent(struct hostent *host);



CARES_EXTERN void ares_free_data(void *dataptr);



CARES_EXTERN const char *ares_strerror(int code);



#ifdef  __cplusplus

ares/ares_data.c

0 → 100644
+142 −0
Original line number Diff line number Diff line 
/* $Id$ */



/* 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:

**

**   FIXME: specify function list.

*/



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;

}

ares/ares_data.h

0 → 100644
+62 −0
Original line number Diff line number Diff line 
/* $Id$ */



/* 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.

 */



typedef enum {

  ARES_DATATYPE_UNKNOWN = 1,   /* unknown data type     */

#if 0

  ARES_DATATYPE_ADDR6TTL,      /* struct ares_addrttl   */

  ARES_DATATYPE_ADDRTTL,       /* struct ares_addr6ttl  */

  ARES_DATATYPE_HOSTENT,       /* struct hostent        */

  ARES_DATATYPE_OPTIONS,       /* struct ares_options   */

#endif

  ARES_DATATYPE_SRV_REPLY,     /* struct ares_srv_reply */

  ARES_DATATYPE_TXT_REPLY,     /* struct ares_txt_reply */

  ARES_DATATYPE_LAST           /* not used              */

} ares_datatype;



#define ARES_DATATYPE_MARK 0xbead



/*

 * ares_data struct definition is internal to c-ares and shall not

 * be exposed by the public API in order to allow future changes

 * and extensions to it without breaking ABI.  This will be used

 * internally by c-ares as the container of multiple types of data

 * dynamically allocated for which a reference will be returned

 * to the calling application.

 *

 * c-ares API functions returning a pointer to c-ares internally

 * allocated data will actually be returning an interior pointer

 * into this ares_data struct.

 *

 * All this is 'invisible' to the calling application, the only

 * requirement is that this kind of data must be free'ed by the

 * calling application using ares_free_data() with the pointer

 * it has received from a previous c-ares function call.

 */



struct ares_data {

  ares_datatype type;  /* Actual data type identifier. */

  unsigned int  mark;  /* Private ares_data signature. */

  union {

    struct ares_txt_reply txt_reply;

    struct ares_srv_reply srv_reply;

  } data;

};



void *ares_malloc_data(ares_datatype type);



ares_datatype ares_get_datatype(void * dataptr);