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#include "jsonuidauthority.h"
#include "jsonstream.h"

#include <errno.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <pwd.h>

#include <QCoreApplication>
#include <QLocalSocket>
#include <QDebug>

QT_BEGIN_NAMESPACE_JSONSTREAM

/*!
  \class JsonUIDAuthority
  \brief The JsonUIDAuthority class implements a UID-based authentication scheme for JsonServer.

  The JsonUIDAuthority class authorizes Json client connections based on the user ID of the
  client.  This user ID is read directly from the connected socket.

  The name returned by the JsonUIDAuthority class is the name entry in the /etc/passwd
  database.  If a name entry does not exist, the JsonUIDAuthority class sets the name equal
  to the string form of the uid.
 */

/*!
  Construct a JsonUIDAuthority with optional \a parent.
 */

JsonUIDAuthority::JsonUIDAuthority(QObject *parent)
    : JsonAuthority(parent)
{
}

/*!
    Adds a user id \a uid to the list of authorized processes.
    Returns true if the uid was non-zero and could be added.

    Before a process can successfully connect to the server with
    its user id must be added with this method if authorization is required.
*/
bool JsonUIDAuthority::authorize(qint64 uid)
{
    if (m_nameForUid.contains(uid))
        return false;

    errno = 0;
    struct passwd *passwd = getpwuid(uid);
    QString name;
    if (passwd) {
        name = QString::fromLatin1(passwd->pw_name);
    }
    else {
        if (errno) {
            qWarning() << "getpwuid failed with errcode" << errno << uid;
            return false;
        }
        name = QString::number(uid);
    }
    m_nameForUid.insert(uid, name);
    return true;
}


/*!
    Adds a user \a name to the list of authorized processes.
    Returns true if the name was found in the /etc/passwd file
    and could be added.
*/
bool JsonUIDAuthority::authorize(const QString& name)
{
    errno = 0;
    struct passwd *passwd = getpwnam(name.toLatin1().data());
    if (!passwd) {
        if (errno)
            qWarning() << "getpwnam failed with errno=" << errno << name;
        else
            qWarning() << "Unable to authorize" << name;
        return false;
    }

    if (m_nameForUid.contains(passwd->pw_uid))
        return false;

    m_nameForUid.insert(passwd->pw_uid, name);
    return true;
}

/*!
    Removes a user id \a uid from the list of authorized users.
    Returns true if a process with a matching UID was found.
*/
bool JsonUIDAuthority::deauthorize(qint64 uid)
{
    return m_nameForUid.remove(uid) != 0;
}

/*!
    Removes a user \a name from the list of authorized users.
    Returns true if a process with a matching name was found.
*/
bool JsonUIDAuthority::deauthorize(const QString& name)
{
    QList<qint64> keylist = m_nameForUid.keys(name);
    if (!keylist.length())
        return false;

    foreach (qint64 key, keylist)
        m_nameForUid.remove(key);
    return true;
}

/*!
    Return true if the \a uid is authorized.
 */

bool JsonUIDAuthority::isAuthorized(qint64 uid) const
{
    return m_nameForUid.contains(uid);
}

/*!
    Returns the identify of the client with UID \a uid.
    If no such name is authorized, returns an empty string.
*/

QString JsonUIDAuthority::name(qint64 uid) const
{
    return m_nameForUid.value(uid);
}

/*!
    Authorizes the connection from \a stream if and only if it matches a valid UID.
    Returns an AuthorizationRecord.
*/

AuthorizationRecord JsonUIDAuthority::clientConnected(JsonStream *stream)
{
    AuthorizationRecord authRecord;
    authRecord.state = JsonAuthority::StateNotAuthorized;

    if (!stream)
        return authRecord;

    QLocalSocket *socket = qobject_cast<QLocalSocket*>(stream->device());

    if (!socket)
        return authRecord;

    if (socket->socketDescriptor() == (qintptr)-1) {
        qWarning() << Q_FUNC_INFO << "no socket descriptor available for connection" << socket;
        return authRecord;
    }

    uid_t euid;
#if defined(Q_OS_MAC)
    gid_t egid;
    if (::getpeereid(socket->socketDescriptor(), &euid, &egid) != 0) {
        qWarning() << "getpeereid failed with errcode" << errno << socket->socketDescriptor();
        return authRecord;
    }
#else
    // Check the UID table and return Authorized if appropriate.
    struct ucred cr;
    socklen_t len = sizeof(struct ucred);
    if (::getsockopt(socket->socketDescriptor(), SOL_SOCKET, SO_PEERCRED, &cr, &len) != 0) {
        qWarning() << "getsockopt failed with errcode" << errno << socket->socketDescriptor();
        return authRecord;
    }
    euid = cr.uid;
#endif

    if (m_nameForUid.contains(euid)) {
        authRecord.identifier = m_nameForUid.value(euid);
        authRecord.state      = StateAuthorized;
    }

    return authRecord;
}

/*!
  Ignore any \a message received from \a stream.
 */
AuthorizationRecord JsonUIDAuthority::messageReceived(JsonStream *stream,
                                                      const QJsonObject &message)
{
    Q_UNUSED(stream);
    Q_UNUSED(message);
    AuthorizationRecord authRecord;
    authRecord.state = JsonAuthority::StateNotAuthorized;
    return authRecord;
}

#include "moc_jsonuidauthority.cpp"

QT_END_NAMESPACE_JSONSTREAM