Adding upstream version 3.8.5.upstream/3.8.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 905 insertions, 0 deletions

diff --git a/src/util/myaddrinfo.c b/src/util/myaddrinfo.c
new file mode 100644
index 0000000..5edafde
--- /dev/null
+++ b/src/util/myaddrinfo.c
@@ -0,0 +1,905 @@
+/*++
+/* NAME
+/*	myaddrinfo 3
+/* SUMMARY
+/*	addrinfo encapsulation and emulation
+/* SYNOPSIS
+/*	#include <myaddrinfo.h>
+/*
+/*	#define MAI_V4ADDR_BITS ...
+/*	#define MAI_V6ADDR_BITS ...
+/*	#define MAI_V4ADDR_BYTES ...
+/*	#define MAI_V6ADDR_BYTES ...
+/*
+/*	typedef struct { char buf[....]; } MAI_HOSTNAME_STR;
+/*	typedef struct { char buf[....]; } MAI_HOSTADDR_STR;
+/*	typedef struct { char buf[....]; } MAI_SERVNAME_STR;
+/*	typedef struct { char buf[....]; } MAI_SERVPORT_STR;
+/*
+/*	int	hostname_to_sockaddr(hostname, service, socktype, result)
+/*	const char *hostname;
+/*	const char *service;
+/*	int	socktype;
+/*	struct addrinfo **result;
+/*
+/*	int	hostname_to_sockaddr_pf(hostname, pf, service, socktype, result)
+/*	const char *hostname;
+/*	int	pf;
+/*	const char *service;
+/*	int	socktype;
+/*	struct addrinfo **result;
+/*
+/*	int	hostaddr_to_sockaddr(hostaddr, service, socktype, result)
+/*	const char *hostaddr;
+/*	const char *service;
+/*	int	socktype;
+/*	struct addrinfo **result;
+/*
+/*	int	sockaddr_to_hostaddr(sa, salen, hostaddr, portnum, socktype)
+/*	const struct sockaddr *sa;
+/*	SOCKADDR_SIZE salen;
+/*	MAI_HOSTADDR_STR *hostaddr;
+/*	MAI_SERVPORT_STR *portnum;
+/*	int	socktype;
+/*
+/*	int	sockaddr_to_hostname(sa, salen, hostname, service, socktype)
+/*	const struct sockaddr *sa;
+/*	SOCKADDR_SIZE salen;
+/*	MAI_HOSTNAME_STR *hostname;
+/*	MAI_SERVNAME_STR *service;
+/*	int	socktype;
+/*
+/*	const char *MAI_STRERROR(error)
+/*	int	error;
+/* DESCRIPTION
+/*	This module provides a simplified user interface to the
+/*	getaddrinfo(3) and getnameinfo(3) routines (which provide
+/*	a unified interface to manipulate IPv4 and IPv6 socket
+/*	address structures).
+/*
+/*	On systems without getaddrinfo(3) and getnameinfo(3) support,
+/*	emulation for IPv4 only can be enabled by defining
+/*	EMULATE_IPV4_ADDRINFO.
+/*
+/*	hostname_to_sockaddr() looks up the binary addresses for
+/*	the specified symbolic hostname or numeric address.  The
+/*	result should be destroyed with freeaddrinfo(). A null host
+/*	pointer converts to the null host address.
+/*
+/*	hostname_to_sockaddr_pf() is an extended interface that
+/*	provides a protocol family override.
+/*
+/*	hostaddr_to_sockaddr() converts a printable network address
+/*	into the corresponding binary form.  The result should be
+/*	destroyed with freeaddrinfo(). A null host pointer converts
+/*	to the null host address.
+/*
+/*	sockaddr_to_hostaddr() converts a binary network address
+/*	into printable form. The result buffers should be large
+/*	enough to hold the printable address or port including the
+/*	null terminator.
+/*	This function strips off the IPv6 datalink suffix.
+/*
+/*	sockaddr_to_hostname() converts a binary network address
+/*	into a hostname or service.  The result buffer should be
+/*	large enough to hold the hostname or service including the
+/*	null terminator. This routine rejects malformed hostnames
+/*	or numeric hostnames and pretends that the lookup failed.
+/*
+/*	MAI_STRERROR() is an unsafe macro (it evaluates the argument
+/*	multiple times) that invokes strerror() or gai_strerror()
+/*	as appropriate.
+/*
+/*	This module exports the following constants that should be
+/*	user for storage allocation of name or address information:
+/* .IP MAI_V4ADDR_BITS
+/* .IP MAI_V6ADDR_BITS
+/* .IP MAI_V4ADDR_BYTES
+/* .IP MAI_V6ADDR_BYTES
+/*	The number of bits or bytes needed to store a binary
+/*	IPv4 or IPv6 network address.
+/* .PP
+/*	The types MAI_HOST{NAME,ADDR}_STR and MAI_SERV{NAME,PORT}_STR
+/*	implement buffers for the storage of the string representations
+/*	of symbolic or numerical hosts or services. Do not use
+/*	buffer types other than the ones that are expected here,
+/*	or things will blow up with buffer overflow problems.
+/*
+/*	Arguments:
+/* .IP hostname
+/*	On input to hostname_to_sockaddr(), a numeric or symbolic
+/*	hostname, or a null pointer (meaning the wild-card listen
+/*	address).  On output from sockaddr_to_hostname(), storage
+/*	for the result hostname, or a null pointer.
+/* .IP pf
+/*	Protocol type: PF_UNSPEC (meaning: use any protocol that is
+/*	available), PF_INET, or PF_INET6.  This argument is ignored
+/*	in EMULATE_IPV4_ADDRINFO mode.
+/* .IP hostaddr
+/*	On input to hostaddr_to_sockaddr(), a numeric hostname,
+/*	or a null pointer (meaning the wild-card listen address).
+/*	On output from sockaddr_to_hostaddr(), storage for the
+/*	result hostaddress, or a null pointer.
+/* .IP service
+/*	On input to hostname/addr_to_sockaddr(), a numeric or
+/*	symbolic service name, or a null pointer in which case the
+/*	socktype argument is ignored.  On output from
+/*	sockaddr_to_hostname/addr(), storage for the result service
+/*	name, or a null pointer.
+/* .IP portnum
+/*	Storage for the result service port number, or a null pointer.
+/* .IP socktype
+/*	Socket type: SOCK_STREAM, SOCK_DGRAM, etc. This argument is
+/*	ignored when no service or port are specified.
+/* .IP sa
+/*	Protocol-independent socket address structure.
+/* .IP salen
+/*	Protocol-dependent socket address structure size in bytes.
+/* SEE ALSO
+/*	getaddrinfo(3), getnameinfo(3), freeaddrinfo(3), gai_strerror(3)
+/* DIAGNOSTICS
+/*	All routines either return 0 upon success, or an error code
+/*	that is compatible with gai_strerror().
+/*
+/*	On systems where addrinfo support is emulated by Postfix,
+/*	some out-of-memory errors are not reported to the caller,
+/*	but are handled by mymalloc().
+/* BUGS
+/*	The IPv4-only emulation code does not support requests that
+/*	specify a service but no socket type. It returns an error
+/*	indication, instead of enumerating all the possible answers.
+/*
+/*	The hostname/addr_to_sockaddr() routines should accept a
+/*	list of address families that the caller is interested in,
+/*	and they should return only information of those types.
+/*
+/*	Unfortunately, it is not possible to remove unwanted address
+/*	family results from hostname_to_sockaddr(), because we
+/*	don't know how the system library routine getaddrinfo()
+/*	allocates memory.  For example, getaddrinfo() could save
+/*	space by referencing the same string object from multiple
+/*	addrinfo structures; or it could allocate a string object
+/*	and the addrinfo structure as one memory block.
+/*
+/*	We could get around this by copying getaddrinfo() results
+/*	to our own private data structures, but that would only
+/*	make an already expensive API even more expensive.
+/*
+/*	A better workaround is to return a vector of addrinfo
+/*	pointers to the elements that contain only the elements
+/*	that the caller is interested in. The pointer to the
+/*	original getaddrinfo() result can be hidden at the end
+/*	after the null terminator, or before the first element.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>			/* sprintf() */
+
+/* Utility library. */
+
+#include <mymalloc.h>
+#include <valid_hostname.h>
+#include <sock_addr.h>
+#include <stringops.h>
+#include <msg.h>
+#include <inet_proto.h>
+#include <myaddrinfo.h>
+#include <split_at.h>
+#include <known_tcp_ports.h>
+
+/* Application-specific. */
+
+ /*
+  * Use an old trick to save some space: allocate space for two objects in
+  * one. In Postfix we often use this trick for structures that have an array
+  * of things at the end.
+  */
+struct ipv4addrinfo {
+    struct addrinfo info;
+    struct sockaddr_in sin;
+};
+
+ /*
+  * When we're not interested in service ports, we must pick a socket type
+  * otherwise getaddrinfo() will give us duplicate results: one set for TCP,
+  * and another set for UDP. For consistency, we'll use the same default
+  * socket type for the results from emulation mode.
+  */
+#define MAI_SOCKTYPE	SOCK_STREAM	/* getaddrinfo() query */
+
+#ifdef EMULATE_IPV4_ADDRINFO
+
+/* clone_ipv4addrinfo - clone ipv4addrinfo structure */
+
+static struct ipv4addrinfo *clone_ipv4addrinfo(struct ipv4addrinfo * tp)
+{
+    struct ipv4addrinfo *ip;
+
+    ip = (struct ipv4addrinfo *) mymalloc(sizeof(*ip));
+    *ip = *tp;
+    ip->info.ai_addr = (struct sockaddr *) &(ip->sin);
+    return (ip);
+}
+
+/* init_ipv4addrinfo - initialize an ipv4addrinfo structure */
+
+static void init_ipv4addrinfo(struct ipv4addrinfo * ip, int socktype)
+{
+
+    /*
+     * Portability: null pointers aren't necessarily all-zero bits, so we
+     * make explicit assignments to all the pointers that we're aware of.
+     */
+    memset((void *) ip, 0, sizeof(*ip));
+    ip->info.ai_family = PF_INET;
+    ip->info.ai_socktype = socktype;
+    ip->info.ai_protocol = 0;			/* XXX */
+    ip->info.ai_addrlen = sizeof(ip->sin);
+    ip->info.ai_canonname = 0;
+    ip->info.ai_addr = (struct sockaddr *) &(ip->sin);
+    ip->info.ai_next = 0;
+    ip->sin.sin_family = AF_INET;
+#ifdef HAS_SA_LEN
+    ip->sin.sin_len = sizeof(ip->sin);
+#endif
+}
+
+/* find_service - translate numeric or symbolic service name */
+
+static int find_service(const char *service, int socktype)
+{
+    struct servent *sp;
+    const char *proto;
+    unsigned port;
+
+    service = filter_known_tcp_port(service);
+    if (alldig(service)) {
+	port = atoi(service);
+	return (port < 65536 ? htons(port) : -1);
+    }
+    if (socktype == SOCK_STREAM) {
+	proto = "tcp";
+    } else if (socktype == SOCK_DGRAM) {
+	proto = "udp";
+    } else {
+	return (-1);
+    }
+    if ((sp = getservbyname(service, proto)) != 0) {
+	return (sp->s_port);
+    } else {
+	return (-1);
+    }
+}
+
+#endif
+
+/* hostname_to_sockaddr_pf - hostname to binary address form */
+
+int     hostname_to_sockaddr_pf(const char *hostname, int pf,
+				        const char *service, int socktype,
+				        struct addrinfo ** res)
+{
+#ifdef EMULATE_IPV4_ADDRINFO
+
+    /*
+     * Emulated getaddrinfo(3) version.
+     */
+    static struct ipv4addrinfo template;
+    struct ipv4addrinfo *ip;
+    struct ipv4addrinfo *prev;
+    struct in_addr addr;
+    struct hostent *hp;
+    char  **name_list;
+    int     port;
+
+    /*
+     * Validate the service.
+     */
+    if (service) {
+	if ((port = find_service(service, socktype)) < 0)
+	    return (EAI_SERVICE);
+    } else {
+	port = 0;
+	socktype = MAI_SOCKTYPE;
+    }
+
+    /*
+     * No host means INADDR_ANY.
+     */
+    if (hostname == 0) {
+	ip = (struct ipv4addrinfo *) mymalloc(sizeof(*ip));
+	init_ipv4addrinfo(ip, socktype);
+	ip->sin.sin_addr.s_addr = INADDR_ANY;
+	ip->sin.sin_port = port;
+	*res = &(ip->info);
+	return (0);
+    }
+
+    /*
+     * Numeric host.
+     */
+    if (inet_pton(AF_INET, hostname, (void *) &addr) == 1) {
+	ip = (struct ipv4addrinfo *) mymalloc(sizeof(*ip));
+	init_ipv4addrinfo(ip, socktype);
+	ip->sin.sin_addr = addr;
+	ip->sin.sin_port = port;
+	*res = &(ip->info);
+	return (0);
+    }
+
+    /*
+     * Look up the IPv4 address list.
+     */
+    if ((hp = gethostbyname(hostname)) == 0)
+	return (h_errno == TRY_AGAIN ? EAI_AGAIN : EAI_NODATA);
+    if (hp->h_addrtype != AF_INET
+	|| hp->h_length != sizeof(template.sin.sin_addr))
+	return (EAI_NODATA);
+
+    /*
+     * Initialize the result template.
+     */
+    if (template.info.ai_addrlen == 0)
+	init_ipv4addrinfo(&template, socktype);
+
+    /*
+     * Copy the address information into an addrinfo structure.
+     */
+    prev = &template;
+    for (name_list = hp->h_addr_list; name_list[0]; name_list++) {
+	ip = clone_ipv4addrinfo(prev);
+	ip->sin.sin_addr = IN_ADDR(name_list[0]);
+	ip->sin.sin_port = port;
+	if (prev == &template)
+	    *res = &(ip->info);
+	else
+	    prev->info.ai_next = &(ip->info);
+	prev = ip;
+    }
+    return (0);
+#else
+
+    /*
+     * Native getaddrinfo(3) version.
+     * 
+     * XXX Wild-card listener issues.
+     * 
+     * With most IPv4 plus IPv6 systems, an IPv6 wild-card listener also listens
+     * on the IPv4 wild-card address. Connections from IPv4 clients appear as
+     * IPv4-in-IPv6 addresses; when Postfix support for IPv4 is turned on,
+     * Postfix automatically maps these embedded addresses to their original
+     * IPv4 form. So everything seems to be fine.
+     * 
+     * However, some applications prefer to use separate listener sockets for
+     * IPv4 and IPv6. The Postfix IPv6 patch provided such an example. And
+     * this is where things become tricky. On many systems the IPv6 and IPv4
+     * wild-card listeners cannot coexist. When one is already active, the
+     * other fails with EADDRINUSE. Solaris 9, however, will automagically
+     * "do the right thing" and allow both listeners to coexist.
+     * 
+     * Recent systems have the IPV6_V6ONLY feature (RFC 3493), which tells the
+     * system that we really mean IPv6 when we say IPv6. This allows us to
+     * set up separate wild-card listener sockets for IPv4 and IPv6. So
+     * everything seems to be fine again.
+     * 
+     * The following workaround disables the wild-card IPv4 listener when
+     * IPV6_V6ONLY is unavailable. This is necessary for some Linux versions,
+     * but is not needed for Solaris 9 (which allows IPv4 and IPv6 wild-card
+     * listeners to coexist). Solaris 10 beta already has IPV6_V6ONLY.
+     * 
+     * XXX This workaround obviously breaks if we want to support protocols in
+     * addition to IPv6 and IPv4, but it is needed only until IPv6
+     * implementations catch up with RFC 3493. A nicer fix is to filter the
+     * getaddrinfo() result, and to return a vector of addrinfo pointers to
+     * only those types of elements that the caller has expressed interested
+     * in.
+     * 
+     * XXX Vanilla AIX 5.1 getaddrinfo() does not support a null hostname with
+     * AI_PASSIVE. And since we don't know how getaddrinfo() manages its
+     * memory we can't bypass it for this special case, or freeaddrinfo()
+     * might blow up. Instead we turn off IPV6_V6ONLY in inet_listen(), and
+     * supply a protocol-dependent hard-coded string value to getaddrinfo()
+     * below, so that it will convert into the appropriate wild-card address.
+     * 
+     * XXX AIX 5.[1-3] getaddrinfo() may return a non-null port when a null
+     * service argument is specified.
+     */
+    struct addrinfo hints;
+    int     err;
+
+    memset((void *) &hints, 0, sizeof(hints));
+    hints.ai_family = (pf != PF_UNSPEC) ? pf : inet_proto_info()->ai_family;
+    hints.ai_socktype = service ? socktype : MAI_SOCKTYPE;
+    if (!hostname) {
+	hints.ai_flags = AI_PASSIVE;
+#if !defined(IPV6_V6ONLY) || defined(BROKEN_AI_PASSIVE_NULL_HOST)
+	switch (hints.ai_family) {
+	case PF_UNSPEC:
+	    hints.ai_family = PF_INET6;
+#ifdef BROKEN_AI_PASSIVE_NULL_HOST
+	case PF_INET6:
+	    hostname = "::";
+	    break;
+	case PF_INET:
+	    hostname = "0.0.0.0";
+	    break;
+#endif
+	}
+#endif
+    }
+    if (service) {
+	service = filter_known_tcp_port(service);
+	if (alldig(service))
+	    hints.ai_flags |= AI_NUMERICSERV;
+    }
+    err = getaddrinfo(hostname, service, &hints, res);
+#if defined(BROKEN_AI_NULL_SERVICE)
+    if (service == 0 && err == 0) {
+	struct addrinfo *r;
+	unsigned short *portp;
+
+	for (r = *res; r != 0; r = r->ai_next)
+	    if (*(portp = SOCK_ADDR_PORTP(r->ai_addr)) != 0)
+		*portp = 0;
+    }
+#endif
+    return (err);
+#endif
+}
+
+/* hostaddr_to_sockaddr - printable address to binary address form */
+
+int     hostaddr_to_sockaddr(const char *hostaddr, const char *service,
+			             int socktype, struct addrinfo ** res)
+{
+#ifdef EMULATE_IPV4_ADDRINFO
+
+    /*
+     * Emulated getaddrinfo(3) version.
+     */
+    struct ipv4addrinfo *ip;
+    struct in_addr addr;
+    int     port;
+
+    /*
+     * Validate the service.
+     */
+    if (service) {
+	if ((port = find_service(service, socktype)) < 0)
+	    return (EAI_SERVICE);
+    } else {
+	port = 0;
+	socktype = MAI_SOCKTYPE;
+    }
+
+    /*
+     * No host means INADDR_ANY.
+     */
+    if (hostaddr == 0) {
+	ip = (struct ipv4addrinfo *) mymalloc(sizeof(*ip));
+	init_ipv4addrinfo(ip, socktype);
+	ip->sin.sin_addr.s_addr = INADDR_ANY;
+	ip->sin.sin_port = port;
+	*res = &(ip->info);
+	return (0);
+    }
+
+    /*
+     * Deal with bad address forms.
+     */
+    switch (inet_pton(AF_INET, hostaddr, (void *) &addr)) {
+    case 1:					/* Success */
+	break;
+    default:					/* Unparsable */
+	return (EAI_NONAME);
+    case -1:					/* See errno */
+	return (EAI_SYSTEM);
+    }
+
+    /*
+     * Initialize the result structure.
+     */
+    ip = (struct ipv4addrinfo *) mymalloc(sizeof(*ip));
+    init_ipv4addrinfo(ip, socktype);
+
+    /*
+     * And copy the result.
+     */
+    ip->sin.sin_addr = addr;
+    ip->sin.sin_port = port;
+    *res = &(ip->info);
+
+    return (0);
+#else
+
+    /*
+     * Native getaddrinfo(3) version. See comments in hostname_to_sockaddr().
+     * 
+     * XXX Vanilla AIX 5.1 getaddrinfo() returns multiple results when
+     * converting a printable ipv4 or ipv6 address to socket address with
+     * ai_family=PF_UNSPEC, ai_flags=AI_NUMERICHOST, ai_socktype=SOCK_STREAM,
+     * ai_protocol=0 or IPPROTO_TCP, and service=0. The workaround is to
+     * ignore all but the first result.
+     * 
+     * XXX AIX 5.[1-3] getaddrinfo() may return a non-null port when a null
+     * service argument is specified.
+     */
+    struct addrinfo hints;
+    int     err;
+
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = inet_proto_info()->ai_family;
+    hints.ai_socktype = service ? socktype : MAI_SOCKTYPE;
+    hints.ai_flags = AI_NUMERICHOST;
+    if (!hostaddr) {
+	hints.ai_flags |= AI_PASSIVE;
+#if !defined(IPV6_V6ONLY) || defined(BROKEN_AI_PASSIVE_NULL_HOST)
+	switch (hints.ai_family) {
+	case PF_UNSPEC:
+	    hints.ai_family = PF_INET6;
+#ifdef BROKEN_AI_PASSIVE_NULL_HOST
+	case PF_INET6:
+	    hostaddr = "::";
+	    break;
+	case PF_INET:
+	    hostaddr = "0.0.0.0";
+	    break;
+#endif
+	}
+#endif
+    }
+    if (service) {
+	service = filter_known_tcp_port(service);
+	if (alldig(service))
+	    hints.ai_flags |= AI_NUMERICSERV;
+    }
+    err = getaddrinfo(hostaddr, service, &hints, res);
+#if defined(BROKEN_AI_NULL_SERVICE)
+    if (service == 0 && err == 0) {
+	struct addrinfo *r;
+	unsigned short *portp;
+
+	for (r = *res; r != 0; r = r->ai_next)
+	    if (*(portp = SOCK_ADDR_PORTP(r->ai_addr)) != 0)
+		*portp = 0;
+    }
+#endif
+    return (err);
+#endif
+}
+
+/* sockaddr_to_hostaddr - binary address to printable address form */
+
+int     sockaddr_to_hostaddr(const struct sockaddr *sa, SOCKADDR_SIZE salen,
+			             MAI_HOSTADDR_STR *hostaddr,
+			             MAI_SERVPORT_STR *portnum,
+			             int unused_socktype)
+{
+#ifdef EMULATE_IPV4_ADDRINFO
+    char    portbuf[sizeof("65535")];
+    ssize_t len;
+
+    /*
+     * Emulated getnameinfo(3) version. The buffer length includes the space
+     * for the null terminator.
+     */
+    if (sa->sa_family != AF_INET) {
+	errno = EAFNOSUPPORT;
+	return (EAI_SYSTEM);
+    }
+    if (hostaddr != 0) {
+	if (inet_ntop(AF_INET, (void *) &(SOCK_ADDR_IN_ADDR(sa)),
+		      hostaddr->buf, sizeof(hostaddr->buf)) == 0)
+	    return (EAI_SYSTEM);
+    }
+    if (portnum != 0) {
+	sprintf(portbuf, "%d", ntohs(SOCK_ADDR_IN_PORT(sa)) & 0xffff);
+	if ((len = strlen(portbuf)) >= sizeof(portnum->buf)) {
+	    errno = ENOSPC;
+	    return (EAI_SYSTEM);
+	}
+	memcpy(portnum->buf, portbuf, len + 1);
+    }
+    return (0);
+#else
+    int     ret;
+
+    /*
+     * Native getnameinfo(3) version.
+     */
+    ret = getnameinfo(sa, salen,
+		      hostaddr ? hostaddr->buf : (char *) 0,
+		      hostaddr ? sizeof(hostaddr->buf) : 0,
+		      portnum ? portnum->buf : (char *) 0,
+		      portnum ? sizeof(portnum->buf) : 0,
+		      NI_NUMERICHOST | NI_NUMERICSERV);
+    if (hostaddr != 0 && ret == 0 && sa->sa_family == AF_INET6)
+	(void) split_at(hostaddr->buf, '%');
+    return (ret);
+#endif
+}
+
+/* sockaddr_to_hostname - binary address to printable hostname */
+
+int     sockaddr_to_hostname(const struct sockaddr *sa, SOCKADDR_SIZE salen,
+			             MAI_HOSTNAME_STR *hostname,
+			             MAI_SERVNAME_STR *service,
+			             int socktype)
+{
+#ifdef EMULATE_IPV4_ADDRINFO
+
+    /*
+     * Emulated getnameinfo(3) version.
+     */
+    struct hostent *hp;
+    struct servent *sp;
+    size_t  len;
+
+    /*
+     * Sanity check.
+     */
+    if (sa->sa_family != AF_INET)
+	return (EAI_NODATA);
+
+    /*
+     * Look up the host name.
+     */
+    if (hostname != 0) {
+	if ((hp = gethostbyaddr((char *) &(SOCK_ADDR_IN_ADDR(sa)),
+				sizeof(SOCK_ADDR_IN_ADDR(sa)),
+				AF_INET)) == 0)
+	    return (h_errno == TRY_AGAIN ? EAI_AGAIN : EAI_NONAME);
+
+	/*
+	 * Save the result. The buffer length includes the space for the null
+	 * terminator. Hostname sanity checks are at the end of this
+	 * function.
+	 */
+	if ((len = strlen(hp->h_name)) >= sizeof(hostname->buf)) {
+	    errno = ENOSPC;
+	    return (EAI_SYSTEM);
+	}
+	memcpy(hostname->buf, hp->h_name, len + 1);
+    }
+
+    /*
+     * Look up the service.
+     */
+    if (service != 0) {
+	if ((sp = getservbyport(ntohs(SOCK_ADDR_IN_PORT(sa)),
+			      socktype == SOCK_DGRAM ? "udp" : "tcp")) == 0)
+	    return (EAI_NONAME);
+
+	/*
+	 * Save the result. The buffer length includes the space for the null
+	 * terminator.
+	 */
+	if ((len = strlen(sp->s_name)) >= sizeof(service->buf)) {
+	    errno = ENOSPC;
+	    return (EAI_SYSTEM);
+	}
+	memcpy(service->buf, sp->s_name, len + 1);
+    }
+#else
+
+    /*
+     * Native getnameinfo(3) version.
+     */
+    int     err;
+
+    err = getnameinfo(sa, salen,
+		      hostname ? hostname->buf : (char *) 0,
+		      hostname ? sizeof(hostname->buf) : 0,
+		      service ? service->buf : (char *) 0,
+		      service ? sizeof(service->buf) : 0,
+		      socktype == SOCK_DGRAM ?
+		      NI_NAMEREQD | NI_DGRAM : NI_NAMEREQD);
+    if (err != 0)
+	return (err);
+#endif
+
+    /*
+     * Hostname sanity checks.
+     */
+    if (hostname != 0) {
+	if (valid_hostaddr(hostname->buf, DONT_GRIPE)) {
+	    msg_warn("numeric hostname: %s", hostname->buf);
+	    return (EAI_NONAME);
+	}
+	if (!valid_hostname(hostname->buf, DO_GRIPE))
+	    return (EAI_NONAME);
+    }
+    return (0);
+}
+
+/* myaddrinfo_control - fine control */
+
+void    myaddrinfo_control(int name,...)
+{
+    const char *myname = "myaddrinfo_control";
+    va_list ap;
+
+    for (va_start(ap, name); name != 0; name = va_arg(ap, int)) {
+	switch (name) {
+	default:
+	    msg_panic("%s: bad name %d", myname, name);
+	}
+    }
+    va_end(ap);
+}
+
+#ifdef EMULATE_IPV4_ADDRINFO
+
+/* freeaddrinfo - release storage */
+
+void    freeaddrinfo(struct addrinfo * ai)
+{
+    struct addrinfo *ap;
+    struct addrinfo *next;
+
+    /*
+     * Artifact of implementation: tolerate a null pointer argument.
+     */
+    for (ap = ai; ap != 0; ap = next) {
+	next = ap->ai_next;
+	if (ap->ai_canonname)
+	    myfree(ap->ai_canonname);
+	/* ap->ai_addr is allocated within this memory block */
+	myfree((void *) ap);
+    }
+}
+
+static char *ai_errlist[] = {
+    "Success",
+    "Address family for hostname not supported",	/* EAI_ADDRFAMILY */
+    "Temporary failure in name resolution",	/* EAI_AGAIN	 */
+    "Invalid value for ai_flags",	/* EAI_BADFLAGS   */
+    "Non-recoverable failure in name resolution",	/* EAI_FAIL	 */
+    "ai_family not supported",		/* EAI_FAMILY     */
+    "Memory allocation failure",	/* EAI_MEMORY     */
+    "No address associated with hostname",	/* EAI_NODATA     */
+    "hostname nor servname provided, or not known",	/* EAI_NONAME     */
+    "service name not supported for ai_socktype",	/* EAI_SERVICE    */
+    "ai_socktype not supported",	/* EAI_SOCKTYPE   */
+    "System error returned in errno",	/* EAI_SYSTEM     */
+    "Invalid value for hints",		/* EAI_BADHINTS   */
+    "Resolved protocol is unknown",	/* EAI_PROTOCOL   */
+    "Unknown error",			/* EAI_MAX	  */
+};
+
+/* gai_strerror - error number to string */
+
+char   *gai_strerror(int ecode)
+{
+
+    /*
+     * Note: EAI_SYSTEM errors are not automatically handed over to
+     * strerror(). The application decides.
+     */
+    if (ecode < 0 || ecode > EAI_MAX)
+	ecode = EAI_MAX;
+    return (ai_errlist[ecode]);
+}
+
+#endif
+
+#ifdef TEST
+
+ /*
+  * A test program that takes some info from the command line and runs it
+  * forward and backward through the above conversion routines.
+  */
+#include <stdlib.h>
+#include <msg.h>
+#include <vstream.h>
+#include <msg_vstream.h>
+
+static int compare_family(const void *a, const void *b)
+{
+    struct addrinfo *resa = *(struct addrinfo **) a;
+    struct addrinfo *resb = *(struct addrinfo **) b;
+
+    return (resa->ai_family - resb->ai_family);
+}
+
+int     main(int argc, char **argv)
+{
+    struct addrinfo *info;
+    struct addrinfo *ip;
+    struct addrinfo **resv;
+    MAI_HOSTNAME_STR host;
+    MAI_HOSTADDR_STR addr;
+    size_t  len, n;
+    int     err;
+
+    msg_vstream_init(argv[0], VSTREAM_ERR);
+
+    if (argc != 4)
+	msg_fatal("usage: %s protocols hostname hostaddress", argv[0]);
+
+    inet_proto_init(argv[0], argv[1]);
+
+    msg_info("=== hostname %s ===", argv[2]);
+
+    if ((err = hostname_to_sockaddr(argv[2], (char *) 0, 0, &info)) != 0) {
+	msg_info("hostname_to_sockaddr(%s): %s",
+	  argv[2], err == EAI_SYSTEM ? strerror(errno) : gai_strerror(err));
+    } else {
+	for (len = 0, ip = info; ip != 0; ip = ip->ai_next)
+	    len += 1;
+	resv = (struct addrinfo **) mymalloc(len * sizeof(*resv));
+	for (len = 0, ip = info; ip != 0; ip = ip->ai_next)
+	    resv[len++] = ip;
+	qsort((void *) resv, len, sizeof(*resv), compare_family);
+	for (n = 0; n < len; n++) {
+	    ip = resv[n];
+	    if ((err = sockaddr_to_hostaddr(ip->ai_addr, ip->ai_addrlen, &addr,
+					 (MAI_SERVPORT_STR *) 0, 0)) != 0) {
+		msg_info("sockaddr_to_hostaddr: %s",
+		   err == EAI_SYSTEM ? strerror(errno) : gai_strerror(err));
+		continue;
+	    }
+	    msg_info("%s -> family=%d sock=%d proto=%d %s", argv[2],
+		 ip->ai_family, ip->ai_socktype, ip->ai_protocol, addr.buf);
+	    if ((err = sockaddr_to_hostname(ip->ai_addr, ip->ai_addrlen, &host,
+					 (MAI_SERVNAME_STR *) 0, 0)) != 0) {
+		msg_info("sockaddr_to_hostname: %s",
+		   err == EAI_SYSTEM ? strerror(errno) : gai_strerror(err));
+		continue;
+	    }
+	    msg_info("%s -> %s", addr.buf, host.buf);
+	}
+	freeaddrinfo(info);
+	myfree((void *) resv);
+    }
+
+    msg_info("=== host address %s ===", argv[3]);
+
+    if ((err = hostaddr_to_sockaddr(argv[3], (char *) 0, 0, &ip)) != 0) {
+	msg_info("hostaddr_to_sockaddr(%s): %s",
+	  argv[3], err == EAI_SYSTEM ? strerror(errno) : gai_strerror(err));
+    } else {
+	if ((err = sockaddr_to_hostaddr(ip->ai_addr, ip->ai_addrlen, &addr,
+					(MAI_SERVPORT_STR *) 0, 0)) != 0) {
+	    msg_info("sockaddr_to_hostaddr: %s",
+		   err == EAI_SYSTEM ? strerror(errno) : gai_strerror(err));
+	} else {
+	    msg_info("%s -> family=%d sock=%d proto=%d %s", argv[3],
+		 ip->ai_family, ip->ai_socktype, ip->ai_protocol, addr.buf);
+	    if ((err = sockaddr_to_hostname(ip->ai_addr, ip->ai_addrlen, &host,
+					 (MAI_SERVNAME_STR *) 0, 0)) != 0) {
+		msg_info("sockaddr_to_hostname: %s",
+		   err == EAI_SYSTEM ? strerror(errno) : gai_strerror(err));
+	    } else
+		msg_info("%s -> %s", addr.buf, host.buf);
+	    freeaddrinfo(ip);
+	}
+    }
+    exit(0);
+}
+
+#endif