/****************************************************************************

**

** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).

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** Contact: Nokia Corporation (qt-info@nokia.com)

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** This file is part of the QtNetwork module of the Qt Toolkit.

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** This file contains pre-release code and may not be distributed.

** You may use this file in accordance with the terms and conditions

** contained in the Technology Preview License Agreement accompanying

** this package.

**

** GNU Lesser General Public License Usage

** Alternatively, this file may be used under the terms of the GNU Lesser

** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

** packaging of this file.  Please review the following information to

** ensure the GNU Lesser General Public License version 2.1 requirements

** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

**

** If you have questions regarding the use of this file, please contact

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** $QT_END_LICENSE$

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****************************************************************************/

//#define QHOSTINFO_DEBUG

#include "qplatformdefs.h"

#include "qhostinfo_p.h"

#include "private/qnativesocketengine_p.h"

#include "qiodevice.h"

#include <qbytearray.h>

#include <qlibrary.h>

#include <qurl.h>

#include <qfile.h>

#include <private/qmutexpool_p.h>

#include <private/qnet_unix_p.h>

#include <sys/types.h>

#include <netdb.h>

#include <arpa/inet.h>

#if defined(Q_OS_VXWORKS)

#  include <hostLib.h>

#else

#  include <resolv.h>

#endif

#if defined (QT_NO_GETADDRINFO)

#include <qmutex.h>

QT_BEGIN_NAMESPACE

Q_GLOBAL_STATIC(QMutex, getHostByNameMutex)

QT_END_NAMESPACE

#endif

QT_BEGIN_NAMESPACE

// Almost always the same. If not, specify in qplatformdefs.h.

#if !defined(QT_SOCKOPTLEN_T)

# define QT_SOCKOPTLEN_T QT_SOCKLEN_T

#endif

// HP-UXi has a bug in getaddrinfo(3) that makes it thread-unsafe

// with this flag. So disable it in that platform.

#if defined(AI_ADDRCONFIG) && !defined(Q_OS_HPUX)

#  define Q_ADDRCONFIG          AI_ADDRCONFIG

#endif

typedef struct __res_state *res_state_ptr;

typedef int (*res_init_proto)(void);

static res_init_proto local_res_init = 0;

typedef int (*res_ninit_proto)(res_state_ptr);

static res_ninit_proto local_res_ninit = 0;

typedef void (*res_nclose_proto)(res_state_ptr);

static res_nclose_proto local_res_nclose = 0;

static res_state_ptr local_res = 0;

static void resolveLibrary()

{

#ifndef QT_NO_LIBRARY

    QLibrary lib(QLatin1String("resolv"));

    if (!lib.load())

        return;

    local_res_init = res_init_proto(lib.resolve("__res_init"));

    if (!local_res_init)

        local_res_init = res_init_proto(lib.resolve("res_init"));

    local_res_ninit = res_ninit_proto(lib.resolve("__res_ninit"));

    if (!local_res_ninit)

        local_res_ninit = res_ninit_proto(lib.resolve("res_ninit"));

    if (!local_res_ninit) {

        // if we can't get a thread-safe context, we have to use the global _res state

        local_res = res_state_ptr(lib.resolve("_res"));

    } else {

        local_res_nclose = res_nclose_proto(lib.resolve("res_nclose"));

        if (!local_res_nclose)

            local_res_nclose = res_nclose_proto(lib.resolve("__res_nclose"));

        if (!local_res_nclose)

            local_res_ninit = 0;

    }

#endif

}

QHostInfo QHostInfoAgent::fromName(const QString &hostName)

{

    QHostInfo results;

#if defined(QHOSTINFO_DEBUG)

    qDebug("QHostInfoAgent::fromName(%s) looking up...",

           hostName.toLatin1().constData());

#endif

    // Load res_init on demand.

    static volatile bool triedResolve = false;

    if (!triedResolve) {

#ifndef QT_NO_THREAD

        QMutexLocker locker(QMutexPool::globalInstanceGet(&local_res_init));

#endif

        if (!triedResolve) {

            resolveLibrary();

            triedResolve = true;

        }

    }

    // If res_init is available, poll it.

    if (local_res_init)

        local_res_init();

    QHostAddress address;

    if (address.setAddress(hostName)) {

        // Reverse lookup

// Reverse lookups using getnameinfo are broken on darwin, use gethostbyaddr instead.

#if !defined (QT_NO_GETADDRINFO) && !defined (Q_OS_DARWIN) && !defined (Q_OS_SYMBIAN)

        sockaddr_in sa4;

#ifndef QT_NO_IPV6

        sockaddr_in6 sa6;

#endif

        sockaddr *sa = 0;

        QT_SOCKLEN_T saSize = 0;

        if (address.protocol() == QAbstractSocket::IPv4Protocol) {

            sa = (sockaddr *)&sa4;

            saSize = sizeof(sa4);

            memset(&sa4, 0, sizeof(sa4));

            sa4.sin_family = AF_INET;

            sa4.sin_addr.s_addr = htonl(address.toIPv4Address());

        }

#ifndef QT_NO_IPV6

        else {

            sa = (sockaddr *)&sa6;

            saSize = sizeof(sa6);

            memset(&sa6, 0, sizeof(sa6));

            sa6.sin6_family = AF_INET6;

            memcpy(sa6.sin6_addr.s6_addr, address.toIPv6Address().c, sizeof(sa6.sin6_addr.s6_addr));

        }

#endif

        char hbuf[NI_MAXHOST];

        if (sa && getnameinfo(sa, saSize, hbuf, sizeof(hbuf), 0, 0, 0) == 0)

            results.setHostName(QString::fromLatin1(hbuf));

#else

        in_addr_t inetaddr = qt_safe_inet_addr(hostName.toLatin1().constData());

        struct hostent *ent = gethostbyaddr((const char *)&inetaddr, sizeof(inetaddr), AF_INET);

        if (ent)

            results.setHostName(QString::fromLatin1(ent->h_name));

#endif

        if (results.hostName().isEmpty())

            results.setHostName(address.toString());

        results.setAddresses(QList<QHostAddress>() << address);

        return results;

    }

    // IDN support

    QByteArray aceHostname = QUrl::toAce(hostName);

    results.setHostName(hostName);

    if (aceHostname.isEmpty()) {

        results.setError(QHostInfo::HostNotFound);

        results.setErrorString(hostName.isEmpty() ?

                               QCoreApplication::translate("QHostInfoAgent", "No host name given") :

                               QCoreApplication::translate("QHostInfoAgent", "Invalid hostname"));

        return results;

    }

#if !defined (QT_NO_GETADDRINFO)

    // Call getaddrinfo, and place all IPv4 addresses at the start and

    // the IPv6 addresses at the end of the address list in results.

    addrinfo *res = 0;

    struct addrinfo hints;

    memset(&hints, 0, sizeof(hints));

    hints.ai_family = PF_UNSPEC;

#ifdef Q_ADDRCONFIG

    hints.ai_flags = Q_ADDRCONFIG;

#endif

    int result = getaddrinfo(aceHostname.constData(), 0, &hints, &res);

# ifdef Q_ADDRCONFIG

    if (result == EAI_BADFLAGS) {

        // if the lookup failed with AI_ADDRCONFIG set, try again without it

        hints.ai_flags = 0;

        result = getaddrinfo(aceHostname.constData(), 0, &hints, &res);

    }

# endif

    if (result == 0) {

        addrinfo *node = res;

        QList<QHostAddress> addresses;

        while (node) {

            if (node->ai_family == AF_INET) {

                QHostAddress addr;

                addr.setAddress(ntohl(((sockaddr_in *) node->ai_addr)->sin_addr.s_addr));

                if (!addresses.contains(addr))

                    addresses.append(addr);

            }

#ifndef QT_NO_IPV6

            else if (node->ai_family == AF_INET6) {

                QHostAddress addr;

                addr.setAddress(((sockaddr_in6 *) node->ai_addr)->sin6_addr.s6_addr);

                if (!addresses.contains(addr))

                    addresses.append(addr);

            }

#endif

            node = node->ai_next;

        }

        if (addresses.isEmpty() && node == 0) {

            // Reached the end of the list, but no addresses were found; this

            // means the list contains one or more unknown address types.

            results.setError(QHostInfo::UnknownError);

            results.setErrorString(tr("Unknown address type"));

        }

        results.setAddresses(addresses);

        freeaddrinfo(res);

    } else if (result == EAI_NONAME

               || result ==  EAI_FAIL

#ifdef EAI_NODATA

	       // EAI_NODATA is deprecated in RFC 3493

	       || result == EAI_NODATA

#endif

	       ) {

        results.setError(QHostInfo::HostNotFound);

        results.setErrorString(tr("Host not found"));

    } else {

        results.setError(QHostInfo::UnknownError);

        results.setErrorString(QString::fromLocal8Bit(gai_strerror(result)));

    }

#else

    // Fall back to gethostbyname for platforms that don't define

    // getaddrinfo. gethostbyname does not support IPv6, and it's not

    // reentrant on all platforms. For now this is okay since we only

    // use one QHostInfoAgent, but if more agents are introduced, locking

    // must be provided.

    QMutexLocker locker(::getHostByNameMutex());

    hostent *result = gethostbyname(aceHostname.constData());

    if (result) {

        if (result->h_addrtype == AF_INET) {

            QList<QHostAddress> addresses;

            for (char **p = result->h_addr_list; *p != 0; p++) {

                QHostAddress addr;

                addr.setAddress(ntohl(*((quint32 *)*p)));

                if (!addresses.contains(addr))

                    addresses.prepend(addr);

            }

            results.setAddresses(addresses);

        } else {

            results.setError(QHostInfo::UnknownError);

            results.setErrorString(tr("Unknown address type"));

        }

#if !defined(Q_OS_VXWORKS)

    } else if (h_errno == HOST_NOT_FOUND || h_errno == NO_DATA

               || h_errno == NO_ADDRESS) {

        results.setError(QHostInfo::HostNotFound);

        results.setErrorString(tr("Host not found"));

#endif

    } else {

        results.setError(QHostInfo::UnknownError);

        results.setErrorString(tr("Unknown error"));

    }

#endif //  !defined (QT_NO_GETADDRINFO)

#if defined(QHOSTINFO_DEBUG)

    if (results.error() != QHostInfo::NoError) {

        qDebug("QHostInfoAgent::fromName(): error #%d %s",

               h_errno, results.errorString().toLatin1().constData());

    } else {

        QString tmp;

        QList<QHostAddress> addresses = results.addresses();

        for (int i = 0; i < addresses.count(); ++i) {

            if (i != 0) tmp += ", ";

            tmp += addresses.at(i).toString();

        }

        qDebug("QHostInfoAgent::fromName(): found %i entries for \"%s\": {%s}",

               addresses.count(), hostName.toLatin1().constData(),

               tmp.toLatin1().constData());

    }

#endif

    return results;

}

QString QHostInfo::localHostName()

{

    char hostName[512];

    if (gethostname(hostName, sizeof(hostName)) == -1)

        return QString();

    hostName[sizeof(hostName) - 1] = '\0';

    return QString::fromLocal8Bit(hostName);

}

QString QHostInfo::localDomainName()

{

#if !defined(Q_OS_VXWORKS)

    resolveLibrary();

    if (local_res_ninit) {

        // using thread-safe version

        res_state_ptr state = res_state_ptr(qMalloc(sizeof(*state)));

        Q_CHECK_PTR(state);

        memset(state, 0, sizeof(*state));

        local_res_ninit(state);

        QString domainName = QUrl::fromAce(state->defdname);

        if (domainName.isEmpty())

            domainName = QUrl::fromAce(state->dnsrch[0]);

        local_res_nclose(state);

        qFree(state);

        return domainName;

    }

    if (local_res_init && local_res) {

        // using thread-unsafe version

#if defined(QT_NO_GETADDRINFO)

        // We have to call res_init to be sure that _res was initialized

        // So, for systems without getaddrinfo (which is thread-safe), we lock the mutex too

        QMutexLocker locker(::getHostByNameMutex());

#endif

        local_res_init();

        QString domainName = QUrl::fromAce(local_res->defdname);

        if (domainName.isEmpty())

            domainName = QUrl::fromAce(local_res->dnsrch[0]);

        return domainName;

    }

#endif

    // nothing worked, try doing it by ourselves:

    QFile resolvconf;

#if defined(_PATH_RESCONF)

    resolvconf.setFileName(QFile::decodeName(_PATH_RESCONF));

#else

    resolvconf.setFileName(QLatin1String("/etc/resolv.conf"));

#endif

    if (!resolvconf.open(QIODevice::ReadOnly))

        return QString();       // failure

    QString domainName;

    while (!resolvconf.atEnd()) {

        QByteArray line = resolvconf.readLine().trimmed();

        if (line.startsWith("domain "))

            return QUrl::fromAce(line.mid(sizeof "domain " - 1).trimmed());

        // in case there's no "domain" line, fall back to the first "search" entry

        if (domainName.isEmpty() && line.startsWith("search ")) {

            QByteArray searchDomain = line.mid(sizeof "search " - 1).trimmed();

            int pos = searchDomain.indexOf(' ');

            if (pos != -1)

                searchDomain.truncate(pos);

            domainName = QUrl::fromAce(searchDomain);

        }

    }

    // return the fallen-back-to searched domain

    return domainName;

}

QT_END_NAMESPACE