<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jun 29, 2015, at 3:20 PM, Eric Christopher <<a href="mailto:echristo@gmail.com" class="">echristo@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Uh...<div class=""><br class=""></div><div class="">Why not just check for the header and use that?</div></div></div></blockquote><div><br class=""></div><div>gethostuuid() is defined in unistd.h on recent versions of Mac. The presence of uuid.h is necessary but not sufficient.</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""> Or check for the functions you need etc at configure/cmake time?</div></div></div></blockquote><div><br class=""></div><div>Sadly, on some platforms and/or versions where this function exists, it returns a bogus value.</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""><br class=""></div><div class="">-eric</div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="">On Mon, Jun 29, 2015 at 3:19 PM Ben Langmuir <<a href="mailto:blangmuir@apple.com" class="">blangmuir@apple.com</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: benlangmuir<br class="">
Date: Mon Jun 29 17:16:39 2015<br class="">
New Revision: 241012<br class="">
<br class="">
URL: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject-3Frev-3D241012-26view-3Drev&d=AwMFAg&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=xi4rtlslo_1cL7aM72Bnr-T8S46TO3o1eMdrU9VxrmE&s=D0Outs0Hnnb96ldz0tBR7ZIHbXqhhHyaPm9t2vPd70k&e=" rel="noreferrer" target="_blank" class="">http://llvm.org/viewvc/llvm-project?rev=241012&view=rev</a><br class="">
Log:<br class="">
Reapply "Use gethostuuid() on Mac to identify hosts for LockFileManager"<br class="">
<br class="">
Reapplies r241005 after fixing the build on non-Mac platforms. Original<br class="">
commit message below.<br class="">
<br class="">
The hostname can be very unstable when there are many machines on the<br class="">
network competing for the same name. Using the hardware UUID makes it<br class="">
less likely to have collisions or to consider files written by the<br class="">
current host to be owned by a different one at a later time.<br class="">
<br class="">
<a href="rdar://problem/21512307" class="">rdar://problem/21512307</a><br class="">
<br class="">
Modified:<br class="">
llvm/trunk/lib/Support/LockFileManager.cpp<br class="">
<br class="">
Modified: llvm/trunk/lib/Support/LockFileManager.cpp<br class="">
URL: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_llvm_trunk_lib_Support_LockFileManager.cpp-3Frev-3D241012-26r1-3D241011-26r2-3D241012-26view-3Ddiff&d=AwMFAg&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=xi4rtlslo_1cL7aM72Bnr-T8S46TO3o1eMdrU9VxrmE&s=Osufgrm3LczHMJqrDZaj2Hq3Z8zZv1wqN7DcJFYPzEU&e=" rel="noreferrer" target="_blank" class="">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/LockFileManager.cpp?rev=241012&r1=241011&r2=241012&view=diff</a><br class="">
==============================================================================<br class="">
--- llvm/trunk/lib/Support/LockFileManager.cpp (original)<br class="">
+++ llvm/trunk/lib/Support/LockFileManager.cpp Mon Jun 29 17:16:39 2015<br class="">
@@ -21,6 +21,16 @@<br class="">
#if LLVM_ON_UNIX<br class="">
#include <unistd.h><br class="">
#endif<br class="">
+<br class="">
+#if defined(__APPLE__) && defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && (__MAC_OS_X_VERSION_MIN_REQUIRED > 1050)<br class="">
+#define USE_OSX_GETHOSTUUID 1<br class="">
+#else<br class="">
+#define USE_OSX_GETHOSTUUID 0<br class="">
+#endif<br class="">
+<br class="">
+#if USE_OSX_GETHOSTUUID<br class="">
+#include <uuid/uuid.h><br class="">
+#endif<br class="">
using namespace llvm;<br class="">
<br class="">
/// \brief Attempt to read the lock file with the given name, if it exists.<br class="">
@@ -56,14 +66,45 @@ LockFileManager::readLockFile(StringRef<br class="">
return None;<br class="">
}<br class="">
<br class="">
-bool LockFileManager::processStillExecuting(StringRef Hostname, int PID) {<br class="">
+static std::error_code getHostID(SmallVectorImpl<char> &HostID) {<br class="">
+ HostID.clear();<br class="">
+<br class="">
+#if USE_OSX_GETHOSTUUID<br class="">
+ // On OS X, use the more stable hardware UUID instead of hostname.<br class="">
+ struct timespec wait = {1, 0}; // 1 second.<br class="">
+ uuid_t uuid;<br class="">
+ if (gethostuuid(uuid, &wait) != 0)<br class="">
+ return std::error_code(errno, std::system_category());<br class="">
+<br class="">
+ uuid_string_t UUIDStr;<br class="">
+ uuid_unparse(uuid, UUIDStr);<br class="">
+ StringRef UUIDRef(UUIDStr);<br class="">
+ HostID.append(UUIDRef.begin(), UUIDRef.end());<br class="">
+<br class="">
+#elif LLVM_ON_UNIX<br class="">
+ char HostName[256];<br class="">
+ HostName[255] = 0;<br class="">
+ HostName[0] = 0;<br class="">
+ gethostname(HostName, 255);<br class="">
+ StringRef HostNameRef(HostName);<br class="">
+ HostID.append(HostNameRef.begin(), HostNameRef.end());<br class="">
+<br class="">
+#else<br class="">
+ StringRef Dummy("localhost");<br class="">
+ HostID.append(Dummy.begin(), Dummy.end());<br class="">
+#endif<br class="">
+<br class="">
+ return std::error_code();<br class="">
+}<br class="">
+<br class="">
+bool LockFileManager::processStillExecuting(StringRef HostID, int PID) {<br class="">
#if LLVM_ON_UNIX && !defined(__ANDROID__)<br class="">
- char MyHostname[256];<br class="">
- MyHostname[255] = 0;<br class="">
- MyHostname[0] = 0;<br class="">
- gethostname(MyHostname, 255);<br class="">
+ SmallString<256> StoredHostID;<br class="">
+ if (getHostID(StoredHostID))<br class="">
+ return true; // Conservatively assume it's executing on error.<br class="">
+<br class="">
// Check whether the process is dead. If so, we're done.<br class="">
- if (MyHostname == Hostname && getsid(PID) == -1 && errno == ESRCH)<br class="">
+ if (StoredHostID == HostID && getsid(PID) == -1 && errno == ESRCH)<br class="">
return false;<br class="">
#endif<br class="">
<br class="">
@@ -126,17 +167,18 @@ LockFileManager::LockFileManager(StringR<br class="">
<br class="">
// Write our process ID to our unique lock file.<br class="">
{<br class="">
- raw_fd_ostream Out(UniqueLockFileID, /*shouldClose=*/true);<br class="">
+ SmallString<256> HostID;<br class="">
+ if (auto EC = getHostID(HostID)) {<br class="">
+ Error = EC;<br class="">
+ return;<br class="">
+ }<br class="">
<br class="">
+ raw_fd_ostream Out(UniqueLockFileID, /*shouldClose=*/true);<br class="">
+ Out << HostID << ' ';<br class="">
#if LLVM_ON_UNIX<br class="">
- // FIXME: move getpid() call into LLVM<br class="">
- char hostname[256];<br class="">
- hostname[255] = 0;<br class="">
- hostname[0] = 0;<br class="">
- gethostname(hostname, 255);<br class="">
- Out << hostname << ' ' << getpid();<br class="">
+ Out << getpid();<br class="">
#else<br class="">
- Out << "localhost 1";<br class="">
+ Out << "1";<br class="">
#endif<br class="">
Out.close();<br class="">
<br class="">
<br class="">
<br class="">
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</blockquote></div>
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