Commit b3b2ba31 authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

Gisle Vanem: 

Basically in loops like handle_errors(), 'query->next' was assigned a local
variable and then query was referenced after the memory was freed by
next_server(). I've changed that so next_server() and end_query() returns the
next query. So callers should use this ret-value.

The next problem was that 'server->tcp_buffer_pos' had a random value at entry
to 1st recv() (luckily causing Winsock to return ENOBUFS).

I've also added a ares_writev() for Windows to streamline the code
a bit more.
parent 7f78bc3c

ares/ares_process.c

+23 −19
Original line number Diff line number Diff line
@@ -51,12 +51,12 @@ static void process_timeouts(ares_channel channel, time_t now); 
static void process_answer(ares_channel channel, unsigned char *abuf,

			   int alen, int whichserver, int tcp, int now);

static void handle_error(ares_channel channel, int whichserver, time_t now);

static void next_server(ares_channel channel, struct query *query, time_t now);

static struct query *next_server(ares_channel channel, struct query *query, time_t now);

static int open_tcp_socket(ares_channel channel, struct server_state *server);

static int open_udp_socket(ares_channel channel, struct server_state *server);

static int same_questions(const unsigned char *qbuf, int qlen,

			  const unsigned char *abuf, int alen);

static void end_query(ares_channel channel, struct query *query, int status,

static struct query *end_query(ares_channel channel, struct query *query, int status,

		      unsigned char *abuf, int alen);



/* Something interesting happened on the wire, or there was a timeout.
@@ -98,16 +98,10 @@ static void write_tcp_data(ares_channel channel, fd_set *write_fds, time_t now) 
      for (sendreq = server->qhead; sendreq; sendreq = sendreq->next)

	n++;



#ifdef WIN32

      vec = NULL;

#else

      /* Allocate iovecs so we can send all our data at once. */

      vec = malloc(n * sizeof(struct iovec));

#endif

      if (vec)

	{

#ifdef WIN32

#else

	  /* Fill in the iovecs and send. */

	  n = 0;

	  for (sendreq = server->qhead; sendreq; sendreq = sendreq->next)
@@ -143,7 +137,6 @@ static void write_tcp_data(ares_channel channel, fd_set *write_fds, time_t now) 
		  break;

		}

	    }

#endif

	}

      else

	{
@@ -284,7 +277,7 @@ static void process_timeouts(ares_channel channel, time_t now) 
      if (query->timeout != 0 && now >= query->timeout)

	{

	  query->error_status = ARES_ETIMEOUT;

	  next_server(channel, query, now);

	  next = next_server(channel, query, now);

	}

    }

}
@@ -360,7 +353,7 @@ static void process_answer(ares_channel channel, unsigned char *abuf, 


static void handle_error(ares_channel channel, int whichserver, time_t now)

{

  struct query *query;

  struct query *query, *next;



  /* Reset communications with this server. */

  ares__close_sockets(&channel->servers[whichserver]);
@@ -368,17 +361,19 @@ static void handle_error(ares_channel channel, int whichserver, time_t now) 
  /* Tell all queries talking to this server to move on and not try

   * this server again.

   */

  for (query = channel->queries; query; query = query->next)



  for (query = channel->queries; query; query = next)

    {

      next = query->next;

      if (query->server == whichserver)

	{

	  query->skip_server[whichserver] = 1;

	  next_server(channel, query, now);

	  next = next_server(channel, query, now);

	}

    }

}



static void next_server(ares_channel channel, struct query *query, time_t now)

static struct query *next_server(ares_channel channel, struct query *query, time_t now)

{

  /* Advance to the next server or try. */

  query->server++;
@@ -389,7 +384,7 @@ static void next_server(ares_channel channel, struct query *query, time_t now) 
	  if (!query->skip_server[query->server])

	    {

	      ares__send_query(channel, query, now);

	      return;

	      return (query->next);

	    }

	}

      query->server = 0;
@@ -398,7 +393,7 @@ static void next_server(ares_channel channel, struct query *query, time_t now) 
      if (query->using_tcp)

	break;

    }

  end_query(channel, query, query->error_status, NULL, 0);

  return end_query(channel, query, query->error_status, NULL, 0);

}



void ares__send_query(ares_channel channel, struct query *query, time_t now)
@@ -421,9 +416,12 @@ void ares__send_query(ares_channel channel, struct query *query, time_t now) 
	      return;

	    }

	}

      sendreq = malloc(sizeof(struct send_request));

      sendreq = calloc(sizeof(struct send_request), 1);

      if (!sendreq)

        {

	end_query(channel, query, ARES_ENOMEM, NULL, 0);

          return;

        }

      sendreq->data = query->tcpbuf;

      sendreq->len = query->tcplen;

      sendreq->next = NULL;
@@ -503,6 +501,7 @@ static int open_tcp_socket(ares_channel channel, struct server_state *server) 
    }

  }



  server->tcp_buffer_pos = 0;

  server->tcp_socket = s;

  return 0;

}
@@ -611,10 +610,10 @@ static int same_questions(const unsigned char *qbuf, int qlen, 
  return 1;

}



static void end_query(ares_channel channel, struct query *query, int status,

static struct query *end_query (ares_channel channel, struct query *query, int status,

		      unsigned char *abuf, int alen)

{

  struct query **q;

  struct query **q, *next;

  int i;



  query->callback(query->arg, status, abuf, alen);
@@ -624,6 +623,10 @@ static void end_query(ares_channel channel, struct query *query, int status, 
	break;

    }

  *q = query->next;

  if (*q)

    next = (*q)->next;

  else

    next = NULL;

  free(query->tcpbuf);

  free(query->skip_server);

  free(query);
@@ -636,4 +639,5 @@ static void end_query(ares_channel channel, struct query *query, int status, 
      for (i = 0; i < channel->nservers; i++)

	ares__close_sockets(&channel->servers[i]);

    }

  return (next);

}

ares/nameser.h

+3 −0
Original line number Diff line number Diff line
@@ -26,6 +26,9 @@ struct iovec 


#define getpid() _getpid()



int ares_writev (SOCKET s, const struct iovec *vector, size_t count);

#define writev(s,vect,count)  ares_writev(s,vect,count)



struct timezone { int dummy; };



int ares_gettimeofday(struct timeval *tv, struct timezone *tz);

ares/setup.h

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 


/* now typedef our socket type */

#ifdef WIN32

#include <winsock.h>

typedef SOCKET ares_socket_t;

#define ARES_SOCKET_BAD INVALID_SOCKET

#else

ares/windows_port.c

+34 −0
Original line number Diff line number Diff line
@@ -5,6 +5,8 @@ 
#include <stdlib.h>

#include <ctype.h>

#include <string.h>

#include <errno.h>

#include <malloc.h>



#include "nameser.h"
@@ -52,4 +54,36 @@ ares_gettimeofday(struct timeval *tv, struct timezone *tz) 
    return 0;

}



int

ares_writev (SOCKET s, const struct iovec *vector, size_t count)

{

  char *buffer, *bp;

  size_t i, bytes = 0;



  /* Find the total number of bytes to write

   */

  for (i = 0; i < count; i++)

      bytes += vector[i].iov_len;



  if (bytes == 0)   /* not an error */

     return (0);



  /* Allocate a temporary buffer to hold the data

   */

  buffer = bp = (char*) alloca (bytes);

  if (!buffer)

  {

    errno = ENOMEM;

    return (-1);

  }



  /* Copy the data into buffer.

   */

  for (i = 0; i < count; ++i)

  {

    memcpy (bp, vector[i].iov_base, vector[i].iov_len);

    bp += vector[i].iov_len;

  }

  return send (s, (const void*)buffer, bytes, 0);

}

#endif /* WIN32 builds only */