From cb936df2a976f6ddd94b81da37bd36284586773f Mon Sep 17 00:00:00 2001
From: Ben Langmuir <blangmuir@apple.com>
Date: Mon, 29 Jun 2015 21:56:03 +0000
Subject: [PATCH] Revert "Use gethostuuid() on Mac to identify hosts for
 LockFileManager"

Broke non-Mac builds.

This reverts commit r241005.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241007 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Support/LockFileManager.cpp | 68 +++++++--------------------------
 1 file changed, 14 insertions(+), 54 deletions(-)

diff --git a/lib/Support/LockFileManager.cpp b/lib/Support/LockFileManager.cpp
index 83c67b8de76..95e0ece9245 100644
--- a/lib/Support/LockFileManager.cpp
+++ b/lib/Support/LockFileManager.cpp
@@ -21,16 +21,6 @@
 #if LLVM_ON_UNIX
 #include <unistd.h>
 #endif
-
-#if defined(__APPLE__) && defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && (__MAC_OS_X_VERSION_MIN_REQUIRED > 1050)
-#define USE_OSX_GETHOSTUUID 1
-#else
-#define USE_OSX_GETHOSTUUID 0
-#endif
-
-#if USE_OSX_GETHOSTUUID
-#include <uuid/uuid.h>
-#endif
 using namespace llvm;
 
 /// \brief Attempt to read the lock file with the given name, if it exists.
@@ -66,43 +56,14 @@ LockFileManager::readLockFile(StringRef LockFileName) {
   return None;
 }
 
-static std::error_code getHostID(SmallVectorImpl<char> &HostID) {
-  HostID.clear();
-
-#if USE_OSX_GETHOSTUUID
-  // On OS X, use the more stable hardware UUID instead of hostname.
-  struct timespec wait = {1, 0}; // 1 second.
-  uuid_t uuid;
-  if (gethostuuid(uuid, &wait) != 0)
-    return std::error_code(errno, std::system_category());
-
-  uuid_string_t UUIDStr;
-  uuid_unparse(uuid, UUIDStr);
-  assert(strlen(UUIDStr) == 36);
-  HostID.append(&UUIDStr[0], &UUIDStr[36]);
-
-#elif LLVM_ON_UNIX
-  char hostname[256];
-  hostname[255] = 0;
-  hostname[0] = 0;
-  gethostname(hostname, 255);
-  HostID = hostname;
-
-#else
-  HostID = "localhost";
-#endif
-
-  return std::error_code();
-}
-
-bool LockFileManager::processStillExecuting(StringRef HostID, int PID) {
+bool LockFileManager::processStillExecuting(StringRef Hostname, int PID) {
 #if LLVM_ON_UNIX && !defined(__ANDROID__)
-  SmallString<256> StoredHostID;
-  if (getHostID(StoredHostID))
-    return true; // Conservatively assume it's executing on error.
-
+  char MyHostname[256];
+  MyHostname[255] = 0;
+  MyHostname[0] = 0;
+  gethostname(MyHostname, 255);
   // Check whether the process is dead. If so, we're done.
-  if (StoredHostID == HostID && getsid(PID) == -1 && errno == ESRCH)
+  if (MyHostname == Hostname && getsid(PID) == -1 && errno == ESRCH)
     return false;
 #endif
 
@@ -165,18 +126,17 @@ LockFileManager::LockFileManager(StringRef FileName)
 
   // Write our process ID to our unique lock file.
   {
-    SmallString<256> HostID;
-    if (auto EC = getHostID(HostID)) {
-      Error = EC;
-      return;
-    }
-
     raw_fd_ostream Out(UniqueLockFileID, /*shouldClose=*/true);
-    Out << HostID << ' ';
+
 #if LLVM_ON_UNIX
-    Out << getpid();
+    // FIXME: move getpid() call into LLVM
+    char hostname[256];
+    hostname[255] = 0;
+    hostname[0] = 0;
+    gethostname(hostname, 255);
+    Out << hostname << ' ' << getpid();
 #else
-    Out << "1";
+    Out << "localhost 1";
 #endif
     Out.close();