Bug 18800: Remove localhost DNS lookup in nsProfileLock.cpp

    if (!mReplacedLockTime)

        aLockFile->GetLastModifiedTimeOfLink(&mReplacedLockTime);

    // For Tor Browser, avoid a DNS lookup here so the Tor network is not

    // bypassed. Instead, always use 127.0.0.1 for the IP address portion

    // of the lock signature, which may cause the browser to refuse to

    // start in the rare event that all of the following conditions are met:

    //   1. The browser profile is on a network file system.

    //   2. The file system does not support fcntl() locking.

    //   3. Tor Browser is run from two different computers at the same time.

    struct in_addr inaddr;

    inaddr.s_addr = htonl(INADDR_LOOPBACK);

    char hostname[256];

    PRStatus status = PR_GetSystemInfo(PR_SI_HOSTNAME, hostname, sizeof hostname);

    if (status == PR_SUCCESS)

    {

        char netdbbuf[PR_NETDB_BUF_SIZE];

        PRHostEnt hostent;

        status = PR_GetHostByName(hostname, netdbbuf, sizeof netdbbuf, &hostent);

        if (status == PR_SUCCESS)

            memcpy(&inaddr, hostent.h_addr, sizeof inaddr);

    }

    char *signature =

        PR_smprintf("%s:%s%lu", inet_ntoa(inaddr), aHaveFcntlLock ? "+" : "",

                    (unsigned long)getpid());