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);

  }

  mozilla::SmprintfPointer signature =

      mozilla::Smprintf("%s:%s%lu", inet_ntoa(inaddr),

                        aHaveFcntlLock ? "+" : "", (unsigned long)getpid());