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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:37:14 +0000 |
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| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:37:14 +0000 |
| commit | ea648e70a989cca190cd7403fe892fd2dcc290b4 (patch) | |
| tree | e2b6b1c647da68b0d4d66082835e256eb30970e8 /lib/lwres/man/lwres_gethostent.html | |
| parent | Initial commit. (diff) | |
| download | bind9-ea648e70a989cca190cd7403fe892fd2dcc290b4.tar.xz bind9-ea648e70a989cca190cd7403fe892fd2dcc290b4.zip | |
Adding upstream version 1:9.11.5.P4+dfsg.upstream/1%9.11.5.P4+dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
| -rw-r--r-- | lib/lwres/man/lwres_gethostent.html | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/lib/lwres/man/lwres_gethostent.html b/lib/lwres/man/lwres_gethostent.html new file mode 100644 index 0000000..a67e8da --- /dev/null +++ b/lib/lwres/man/lwres_gethostent.html @@ -0,0 +1,477 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<!-- + - Copyright (C) 2001, 2004, 2005, 2007, 2014-2016, 2018, 2019 Internet Systems Consortium, Inc. ("ISC") + - + - This Source Code Form is subject to the terms of the Mozilla Public + - License, v. 2.0. If a copy of the MPL was not distributed with this + - file, You can obtain one at http://mozilla.org/MPL/2.0/. +--> +<html lang="en"> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>lwres_gethostent</title> +<meta name="generator" content="DocBook XSL Stylesheets V1.78.1"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry"> +<a name="id-1"></a><div class="titlepage"></div> + + + + + + + + <div class="refnamediv"> +<h2>Name</h2> +<p> + lwres_gethostbyname, + lwres_gethostbyname2, + lwres_gethostbyaddr, + lwres_gethostent, + lwres_sethostent, + lwres_endhostent, + lwres_gethostbyname_r, + lwres_gethostbyaddr_r, + lwres_gethostent_r, + lwres_sethostent_r, + lwres_endhostent_r + — lightweight resolver get network host entry + </p> +</div> + <div class="refsynopsisdiv"> +<h2>Synopsis</h2> + <div class="funcsynopsis"> +<pre class="funcsynopsisinfo">#include <lwres/netdb.h></pre> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr> +<td><code class="funcdef"> +struct hostent * +<b class="fsfunc">lwres_gethostbyname</b>(</code></td> +<td>const char *<var class="pdparam">name</var><code>)</code>;</td> +</tr></table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"> +<tr> +<td><code class="funcdef"> +struct hostent * +<b class="fsfunc">lwres_gethostbyname2</b>(</code></td> +<td>const char *<var class="pdparam">name</var>, </td> +</tr> +<tr> +<td> </td> +<td>int <var class="pdparam">af</var><code>)</code>;</td> +</tr> +</table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"> +<tr> +<td><code class="funcdef"> +struct hostent * +<b class="fsfunc">lwres_gethostbyaddr</b>(</code></td> +<td>const char *<var class="pdparam">addr</var>, </td> +</tr> +<tr> +<td> </td> +<td>int <var class="pdparam">len</var>, </td> +</tr> +<tr> +<td> </td> +<td>int <var class="pdparam">type</var><code>)</code>;</td> +</tr> +</table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr> +<td><code class="funcdef"> +struct hostent * +<b class="fsfunc">lwres_gethostent</b>(</code></td> +<td>void<code>)</code>;</td> +</tr></table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_sethostent</b>(</code></td> +<td>int <var class="pdparam">stayopen</var><code>)</code>;</td> +</tr></table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_endhostent</b>(</code></td> +<td>void<code>)</code>;</td> +</tr></table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"> +<tr> +<td><code class="funcdef"> +struct hostent * +<b class="fsfunc">lwres_gethostbyname_r</b>(</code></td> +<td>const char *<var class="pdparam">name</var>, </td> +</tr> +<tr> +<td> </td> +<td>struct hostent *<var class="pdparam">resbuf</var>, </td> +</tr> +<tr> +<td> </td> +<td>char *<var class="pdparam">buf</var>, </td> +</tr> +<tr> +<td> </td> +<td>int <var class="pdparam">buflen</var>, </td> +</tr> +<tr> +<td> </td> +<td>int *<var class="pdparam">error</var><code>)</code>;</td> +</tr> +</table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"> +<tr> +<td><code class="funcdef"> +struct hostent * +<b class="fsfunc">lwres_gethostbyaddr_r</b>(</code></td> +<td>const char *<var class="pdparam">addr</var>, </td> +</tr> +<tr> +<td> </td> +<td>int <var class="pdparam">len</var>, </td> +</tr> +<tr> +<td> </td> +<td>int <var class="pdparam">type</var>, </td> +</tr> +<tr> +<td> </td> +<td>struct hostent *<var class="pdparam">resbuf</var>, </td> +</tr> +<tr> +<td> </td> +<td>char *<var class="pdparam">buf</var>, </td> +</tr> +<tr> +<td> </td> +<td>int <var class="pdparam">buflen</var>, </td> +</tr> +<tr> +<td> </td> +<td>int *<var class="pdparam">error</var><code>)</code>;</td> +</tr> +</table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"> +<tr> +<td><code class="funcdef"> +struct hostent * +<b class="fsfunc">lwres_gethostent_r</b>(</code></td> +<td>struct hostent *<var class="pdparam">resbuf</var>, </td> +</tr> +<tr> +<td> </td> +<td>char *<var class="pdparam">buf</var>, </td> +</tr> +<tr> +<td> </td> +<td>int <var class="pdparam">buflen</var>, </td> +</tr> +<tr> +<td> </td> +<td>int *<var class="pdparam">error</var><code>)</code>;</td> +</tr> +</table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_sethostent_r</b>(</code></td> +<td>int <var class="pdparam">stayopen</var><code>)</code>;</td> +</tr></table> +<div class="funcprototype-spacer"> </div> +<table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr> +<td><code class="funcdef"> +void +<b class="fsfunc">lwres_endhostent_r</b>(</code></td> +<td>void<code>)</code>;</td> +</tr></table> +<div class="funcprototype-spacer"> </div> +</div> + </div> + + <div class="refsection"> +<a name="id-1.7"></a><h2>DESCRIPTION</h2> + + <p> + These functions provide hostname-to-address and + address-to-hostname lookups by means of the lightweight resolver. + They are similar to the standard + <span class="citerefentry"> + <span class="refentrytitle">gethostent</span>(3) + </span> + functions provided by most operating systems. + They use a + <span class="type">struct hostent</span> + which is usually defined in + <code class="filename"><namedb.h></code>. + </p> + <pre class="programlisting"> +struct hostent { + char *h_name; /* official name of host */ + char **h_aliases; /* alias list */ + int h_addrtype; /* host address type */ + int h_length; /* length of address */ + char **h_addr_list; /* list of addresses from name server */ +}; +#define h_addr h_addr_list[0] /* address, for backward compatibility */ +</pre> +<p> + </p> + <p> + The members of this structure are: + </p> +<div class="variablelist"><dl class="variablelist"> +<dt><span class="term"><code class="constant">h_name</code></span></dt> +<dd> + <p> + The official (canonical) name of the host. + </p> + </dd> +<dt><span class="term"><code class="constant">h_aliases</code></span></dt> +<dd> + <p> + A NULL-terminated array of alternate names (nicknames) for the + host. + </p> + </dd> +<dt><span class="term"><code class="constant">h_addrtype</code></span></dt> +<dd> + <p> + The type of address being returned — + <span class="type">PF_INET</span> + or + <span class="type">PF_INET6</span>. + </p> + </dd> +<dt><span class="term"><code class="constant">h_length</code></span></dt> +<dd> + <p> + The length of the address in bytes. + </p> + </dd> +<dt><span class="term"><code class="constant">h_addr_list</code></span></dt> +<dd> + <p> + A <span class="type">NULL</span> + terminated array of network addresses for the host. + Host addresses are returned in network byte order. + </p> + </dd> +</dl></div> +<p> + </p> + <p> + For backward compatibility with very old software, + <code class="constant">h_addr</code> + is the first address in + <code class="constant">h_addr_list.</code> + </p> + <p><code class="function">lwres_gethostent()</code>, + <code class="function">lwres_sethostent()</code>, + <code class="function">lwres_endhostent()</code>, + <code class="function">lwres_gethostent_r()</code>, + <code class="function">lwres_sethostent_r()</code> + and + <code class="function">lwres_endhostent_r()</code> + provide iteration over the known host entries on systems that + provide such functionality through facilities like + <code class="filename">/etc/hosts</code> + or NIS. The lightweight resolver does not currently implement + these functions; it only provides them as stub functions that always + return failure. + </p> + + <p><code class="function">lwres_gethostbyname()</code> + and <code class="function">lwres_gethostbyname2()</code> look up the + hostname <em class="parameter"><code>name</code></em>. + <code class="function">lwres_gethostbyname()</code> always looks for an + IPv4 address while <code class="function">lwres_gethostbyname2()</code> + looks for an address of protocol family + <em class="parameter"><code>af</code></em>: either <span class="type">PF_INET</span> or + <span class="type">PF_INET6</span> — IPv4 or IPV6 addresses + respectively. Successful calls of the functions return a + <span class="type">struct hostent</span>for the name that was looked up. + <span class="type">NULL</span> is returned if the lookups by + <code class="function">lwres_gethostbyname()</code> or + <code class="function">lwres_gethostbyname2()</code> fail. + </p> + + <p> + Reverse lookups of addresses are performed by + <code class="function">lwres_gethostbyaddr()</code>. + <em class="parameter"><code>addr</code></em> is an address of length + <em class="parameter"><code>len</code></em> bytes and protocol family + <em class="parameter"><code>type</code></em> — <span class="type">PF_INET</span> or + <span class="type">PF_INET6</span>. + <code class="function">lwres_gethostbyname_r()</code> is a + thread-safe function + for forward lookups. If an error occurs, an error code is returned in + <em class="parameter"><code>*error</code></em>. + <em class="parameter"><code>resbuf</code></em> is a pointer to a + <span class="type">struct hostent</span> which is initialised by a successful call to + <code class="function">lwres_gethostbyname_r()</code>. + <em class="parameter"><code>buf</code></em> is a buffer of length + <em class="parameter"><code>len</code></em> bytes which is used to store the + <code class="constant">h_name</code>, <code class="constant">h_aliases</code>, and + <code class="constant">h_addr_list</code> elements of the + <span class="type">struct hostent</span> returned in <em class="parameter"><code>resbuf</code></em>. + Successful calls to <code class="function">lwres_gethostbyname_r()</code> + return <em class="parameter"><code>resbuf</code></em>, + which is a pointer to the <span class="type">struct hostent</span> it created. + </p> + + <p><code class="function">lwres_gethostbyaddr_r()</code> + is a thread-safe function + that performs a reverse lookup of address <em class="parameter"><code>addr</code></em> + which is <em class="parameter"><code>len</code></em> bytes long and is of + protocol + family <em class="parameter"><code>type</code></em> — <span class="type">PF_INET</span> or + <span class="type">PF_INET6</span>. If an error occurs, the error code is returned + in <em class="parameter"><code>*error</code></em>. The other function + parameters are + identical to those in <code class="function">lwres_gethostbyname_r()</code>. + <em class="parameter"><code>resbuf</code></em> is a pointer to a + <span class="type">struct hostent</span> which is initialised by a successful call to + <code class="function">lwres_gethostbyaddr_r()</code>. + <em class="parameter"><code>buf</code></em> is a buffer of length + <em class="parameter"><code>len</code></em> bytes which is used to store the + <code class="constant">h_name</code>, <code class="constant">h_aliases</code>, and + <code class="constant">h_addr_list</code> elements of the + <span class="type">struct hostent</span> returned in <em class="parameter"><code>resbuf</code></em>. + Successful calls to <code class="function">lwres_gethostbyaddr_r()</code> return + <em class="parameter"><code>resbuf</code></em>, which is a pointer to the + <code class="function">struct hostent()</code> it created. + </p> + + </div> + + <div class="refsection"> +<a name="id-1.8"></a><h2>RETURN VALUES</h2> + + <p> + The functions + <code class="function">lwres_gethostbyname()</code>, + <code class="function">lwres_gethostbyname2()</code>, + <code class="function">lwres_gethostbyaddr()</code>, + and + <code class="function">lwres_gethostent()</code> + return NULL to indicate an error. In this case the global variable + <span class="type">lwres_h_errno</span> + will contain one of the following error codes defined in + <code class="filename"><lwres/netdb.h></code>: + + </p> +<div class="variablelist"><dl class="variablelist"> +<dt><span class="term"><code class="constant">HOST_NOT_FOUND</code></span></dt> +<dd> + <p> + The host or address was not found. + </p> + </dd> +<dt><span class="term"><code class="constant">TRY_AGAIN</code></span></dt> +<dd> + <p> + A recoverable error occurred, e.g., a timeout. + Retrying the lookup may succeed. + </p> + </dd> +<dt><span class="term"><code class="constant">NO_RECOVERY</code></span></dt> +<dd> + <p> + A non-recoverable error occurred. + </p> + </dd> +<dt><span class="term"><code class="constant">NO_DATA</code></span></dt> +<dd> + <p> + The name exists, but has no address information + associated with it (or vice versa in the case + of a reverse lookup). The code NO_ADDRESS + is accepted as a synonym for NO_DATA for backwards + compatibility. + </p> + </dd> +</dl></div> +<p> + </p> + + <p><span class="citerefentry"> + <span class="refentrytitle">lwres_hstrerror</span>(3) + </span> + translates these error codes to suitable error messages. + </p> + + <p><code class="function">lwres_gethostent()</code> + and <code class="function">lwres_gethostent_r()</code> + always return <span class="type">NULL</span>. + </p> + + <p> + Successful calls to <code class="function">lwres_gethostbyname_r()</code> and + <code class="function">lwres_gethostbyaddr_r()</code> return + <em class="parameter"><code>resbuf</code></em>, a pointer to the + <span class="type">struct hostent</span> that was initialised by these functions. They return + <span class="type">NULL</span> if the lookups fail or if <em class="parameter"><code>buf</code></em> + was too small to hold the list of addresses and names referenced by + the <code class="constant">h_name</code>, <code class="constant">h_aliases</code>, and + <code class="constant">h_addr_list</code> elements of the + <span class="type">struct hostent</span>. + If <em class="parameter"><code>buf</code></em> was too small, both + <code class="function">lwres_gethostbyname_r()</code> and + <code class="function">lwres_gethostbyaddr_r()</code> set the global + variable + <span class="type">errno</span> to <span class="errorcode">ERANGE</span>. + </p> + + </div> + <div class="refsection"> +<a name="id-1.9"></a><h2>SEE ALSO</h2> + + <p><span class="citerefentry"> + <span class="refentrytitle">gethostent</span>(3) + </span>, + + <span class="citerefentry"> + <span class="refentrytitle">lwres_getipnode</span>(3) + </span>, + + <span class="citerefentry"> + <span class="refentrytitle">lwres_hstrerror</span>(3) + </span> + </p> + </div> + + <div class="refsection"> +<a name="id-1.10"></a><h2>BUGS</h2> + + <p><code class="function">lwres_gethostbyname()</code>, + <code class="function">lwres_gethostbyname2()</code>, + <code class="function">lwres_gethostbyaddr()</code> + and + <code class="function">lwres_endhostent()</code> + are not thread safe; they return pointers to static data and + provide error codes through a global variable. + Thread-safe versions for name and address lookup are provided by + <code class="function">lwres_gethostbyname_r()</code>, + and + <code class="function">lwres_gethostbyaddr_r()</code> + respectively. + </p> + <p> + The resolver daemon does not currently support any non-DNS + name services such as + <code class="filename">/etc/hosts</code> + or + <span class="type">NIS</span>, + consequently the above functions don't, either. + </p> + </div> +</div></body> +</html> |