- Brad Spencer brought the new function ares_gethostbyname_file() which simply

  Changelog for the c-ares project

* Nov 19 2008 (Daniel Stenberg)

- Brad Spencer brought the new function ares_gethostbyname_file() which simply

  resolves a host name from the given file, using the regular hosts syntax.

* Nov 1 2008 (Daniel Stenberg)

- Carlo Contavalli added support for the glibc "rotate" option, as documented

  in man resolv.conf: 

 ares_query.3 ares_search.3 ares_send.3 ares_strerror.3 ares_timeout.3	    \

 ares_version.3 ares_cancel.3 ares_parse_aaaa_reply.3 ares_getnameinfo.3    \

 ares_getsock.3 ares_parse_ns_reply.3 \

 ares_destroy_options.3 ares_save_options.3

 ares_destroy_options.3 ares_save_options.3 ares_gethostbyname_file.3

                 int type, ares_callback callback, void *arg);

void ares_gethostbyname(ares_channel channel, const char *name, int family,

                        ares_host_callback callback, void *arg);

int ares_gethostbyname_file(ares_channel channel, const char *name,

                            int family, struct hostent **host);

void ares_gethostbyaddr(ares_channel channel, const void *addr, int addrlen,

                        int family, ares_host_callback callback, void *arg);

void ares_getnameinfo(ares_channel channel, const struct sockaddr *sa,

  return 1;

}

/* This is an API method */

int ares_gethostbyname_file(ares_channel channel, const char *name,

                            int family, struct hostent **host)

{

  /* We only take the channel to ensure that ares_init() been called. */

  if(channel == NULL)

    {

      /* Anything will do, really.  This seems fine, and is consistent with

         other error cases. */

      *host = NULL;

      return ARES_ENOTFOUND;

    }

  /* Just chain to the internal implementation we use here; it's exactly

   * what we want.  

   */

  const int result = file_lookup(name, family, host);

  if(result != ARES_SUCCESS)

    {

      /* We guarantee a NULL hostent on failure. */

      *host = NULL;

    }

  return result;

}

static int file_lookup(const char *name, int family, struct hostent **host)

{

  FILE *fp;

.\" $Id$

.\"

.\" Copyright 1998 by the Massachusetts Institute of Technology.

.\"

.\" 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.

.\"

.TH ARES_GETHOSTBYNAME 3 "25 July 1998"

.SH NAME

ares_gethostbyname_file \- Lookup a name in the system's hosts file

.SH SYNOPSIS

.nf

.B #include <ares.h>

.PP

.B void ares_gethostbyname_file(ares_channel \fIchannel\fP, const char *\fIname\fP,

.B 	int \fIfamily\fP, struct hostent **host)

.fi

.SH DESCRIPTION

The

.B ares_gethostbyname_file

function performs a host lookup by name against the system's hosts file (or equivalent local hostname database).  

The

.IR channel

parameter is required, but no asynchronous queries are performed.  Instead, the

lookup is done via the same mechanism used to perform 'f' lookups

(see the

.I lookups

options field in \fIares_init_options(3)\fP).

The parameter

.I name

gives the hostname as a NUL-terminated C string, and

.I family

gives the desired type of address for the resulting host entry.  

.PP

The return value indicates whether the query succeeded and, if not, how it

failed.  It may have any of the following values:

.TP 19

.B ARES_SUCCESS

The host lookup completed successfully and 

.I host

now points to the result (and must be freed with \fIares_free_hostent(3)\fP).

.TP 19

.B ARES_ENOTFOUND

The hostname

.I name

was not found.

.TP 19

.B ARES_EFILE

There was a file I/O error while performing the lookup.

.TP 19

.B ARES_ENOMEM

Memory was exhausted.

.PP

On successful completion of the query, the pointer pointed to by

.I host

points to a

.B struct hostent

containing the address of the host returned by the lookup.  The user must

free the memory pointed to by

.IR host

when finished with it by calling \fIares_free_hostent(3)\fP.  If the lookup did

not complete successfully, 

.I host

will be

.BR NULL .

.SH AVAILABILITY

Added in c-ares 1.5.4

.SH SEE ALSO

.BR ares_gethostbyname (3),

.BR ares_free_hostent (3),

.BR ares_init_options (3)

.SH AUTHOR

Brad Spencer

.br

Copyright 1998 by the Massachusetts Institute of Technology.