int ResolveUtil::getHostnameByAddress(bsl::string *canonicalHostname,
const IPv4Address& address,
int *errorCode)
{
BSLS_ASSERT(canonicalHostname);
struct hostent *hp = NULL;
unsigned int addr = address.ipAddress(); // in network order
#if defined(BSLS_PLATFORM_OS_AIX)
struct hostent hent;
struct hostent_data hdt;
if (gethostbyaddr_r(reinterpret_cast<char *>(&addr),
sizeof (struct in_addr),
AF_INET,
&hent,
&hdt)) {
if (errorCode) {
*errorCode = h_errno;
}
return -1; // RETURN
}
*canonicalHostname = hent.h_name;
#elif defined(BSLS_PLATFORM_OS_SUNOS) || defined(BSLS_PLATFORM_OS_SOLARIS)
struct hostent hent;
char hdt[2048];
int err;
hp = gethostbyaddr_r(reinterpret_cast<char *>(&addr),
sizeof (struct in_addr),
AF_INET,
&hent,
hdt,
sizeof(hdt),
&err);
if (0 == hp) {
if (errorCode) {
*errorCode = err;
}
return -1; // RETURN
}
*canonicalHostname = hp->h_name;
#elif defined(BSLS_PLATFORM_OS_LINUX) \
|| defined(BSLS_PLATFORM_OS_FREEBSD)
struct hostent hent;
char hdt[2048];
int err;
if (gethostbyaddr_r(reinterpret_cast<char *>(&addr),
sizeof (struct in_addr),
AF_INET,
&hent,
hdt,
sizeof(hdt),
&hp,
&err) || 0 == hp) {
if (errorCode) {
*errorCode = err;
}
return -1; // RETURN
}
*canonicalHostname = hp->h_name;
#elif defined(BSLS_PLATFORM_OS_UNIX)
// Standard call cannot be assumed to be re-entrant (it often is not).
{
static bslmt::Mutex mutex;
bslmt::LockGuard<bslmt::Mutex> guard(&mutex);
hp = gethostbyaddr(reinterpret_cast<char *>(&addr),
sizeof (struct in_addr),
AF_INET);
if (0 == hp) {
if (errorCode) {
#ifdef BSLS_PLATFORM_OS_HPUX
*errorCode = h_errno;
#else
*errorCode = errno;
#endif
}
return -1; // RETURN
}
*canonicalHostname = hp->h_name;
}
#elif defined(BSLS_PLATFORM_OS_WINDOWS)
unsigned short port = address.portNumber(); // in host order
struct sockaddr_in saGNI;
char hostName[NI_MAXHOST];
char servInfo[NI_MAXSERV];
saGNI.sin_family = AF_INET;
saGNI.sin_addr.s_addr = addr;
saGNI.sin_port = htons(port);
if (getnameinfo(reinterpret_cast<SOCKADDR *>(&saGNI),
sizeof(sockaddr),
hostName,
sizeof(hostName),
servInfo,
sizeof(servInfo),
NI_NUMERICSERV|NI_NAMEREQD)) {
if (errorCode) {
*errorCode = WSAGetLastError();
}
return -1; // RETURN
}
*canonicalHostname = hostName; // a Fully Qualified Domain Name (FQDN)
#else
#error getHostnameByAddress does not handle current platform type!
#endif
return 0;
}
