Automated merge with file:///Users/nat/linden/viewer-leap-daggy

1 files changed, 1189 insertions, 0 deletions

diff --git a/indra/llcommon/llprocess.cpp b/indra/llcommon/llprocess.cpp
new file mode 100644
index 0000000000..3b17b819bd
--- /dev/null
+++ b/indra/llcommon/llprocess.cpp
@@ -0,0 +1,1189 @@
+/** 
+ * @file llprocess.cpp
+ * @brief Utility class for launching, terminating, and tracking the state of processes.
+ *
+ * $LicenseInfo:firstyear=2008&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2010, Linden Research, Inc.
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * 
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#include "linden_common.h"
+#include "llprocess.h"
+#include "llsdutil.h"
+#include "llsdserialize.h"
+#include "llsingleton.h"
+#include "llstring.h"
+#include "stringize.h"
+#include "llapr.h"
+#include "apr_signal.h"
+#include "llevents.h"
+
+#include <boost/foreach.hpp>
+#include <boost/bind.hpp>
+#include <boost/asio/streambuf.hpp>
+#include <boost/asio/buffers_iterator.hpp>
+#include <iostream>
+#include <stdexcept>
+#include <limits>
+#include <algorithm>
+#include <vector>
+#include <typeinfo>
+#include <utility>
+
+static const char* whichfile_[] = { "stdin", "stdout", "stderr" };
+static std::string empty;
+static LLProcess::Status interpret_status(int status);
+static std::string getDesc(const LLProcess::Params& params);
+
+static std::string whichfile(LLProcess::FILESLOT index)
+{
+	if (index < LL_ARRAY_SIZE(whichfile_))
+		return whichfile_[index];
+	return STRINGIZE("file slot " << index);
+}
+
+/**
+ * Ref-counted "mainloop" listener. As long as there are still outstanding
+ * LLProcess objects, keep listening on "mainloop" so we can keep polling APR
+ * for process status.
+ */
+class LLProcessListener
+{
+	LOG_CLASS(LLProcessListener);
+public:
+	LLProcessListener():
+		mCount(0)
+	{}
+
+	void addPoll(const LLProcess&)
+	{
+		// Unconditionally increment mCount. If it was zero before
+		// incrementing, listen on "mainloop".
+		if (mCount++ == 0)
+		{
+			LL_DEBUGS("LLProcess") << "listening on \"mainloop\"" << LL_ENDL;
+			mConnection = LLEventPumps::instance().obtain("mainloop")
+				.listen("LLProcessListener", boost::bind(&LLProcessListener::tick, this, _1));
+		}
+	}
+
+	void dropPoll(const LLProcess&)
+	{
+		// Unconditionally decrement mCount. If it's zero after decrementing,
+		// stop listening on "mainloop".
+		if (--mCount == 0)
+		{
+			LL_DEBUGS("LLProcess") << "disconnecting from \"mainloop\"" << LL_ENDL;
+			mConnection.disconnect();
+		}
+	}
+
+private:
+	/// called once per frame by the "mainloop" LLEventPump
+	bool tick(const LLSD&)
+	{
+		// Tell APR to sense whether each registered LLProcess is still
+		// running and call handle_status() appropriately. We should be able
+		// to get the same info from an apr_proc_wait(APR_NOWAIT) call; but at
+		// least in APR 1.4.2, testing suggests that even with APR_NOWAIT,
+		// apr_proc_wait() blocks the caller. We can't have that in the
+		// viewer. Hence the callback rigmarole. (Once we update APR, it's
+		// probably worth testing again.) Also -- although there's an
+		// apr_proc_other_child_refresh() call, i.e. get that information for
+		// one specific child, it accepts an 'apr_other_child_rec_t*' that's
+		// mentioned NOWHERE else in the documentation or header files! I
+		// would use the specific call in LLProcess::getStatus() if I knew
+		// how. As it is, each call to apr_proc_other_child_refresh_all() will
+		// call callbacks for ALL still-running child processes. That's why we
+		// centralize such calls, using "mainloop" to ensure it happens once
+		// per frame, and refcounting running LLProcess objects to remain
+		// registered only while needed.
+		LL_DEBUGS("LLProcess") << "calling apr_proc_other_child_refresh_all()" << LL_ENDL;
+		apr_proc_other_child_refresh_all(APR_OC_REASON_RUNNING);
+		return false;
+	}
+
+	/// If this object is destroyed before mCount goes to zero, stop
+	/// listening on "mainloop" anyway.
+	LLTempBoundListener mConnection;
+	unsigned mCount;
+};
+static LLProcessListener sProcessListener;
+
+LLProcess::BasePipe::~BasePipe() {}
+const LLProcess::BasePipe::size_type
+	  // use funky syntax to call max() to avoid blighted max() macros
+	  LLProcess::BasePipe::npos((std::numeric_limits<LLProcess::BasePipe::size_type>::max)());
+
+class WritePipeImpl: public LLProcess::WritePipe
+{
+	LOG_CLASS(WritePipeImpl);
+public:
+	WritePipeImpl(const std::string& desc, apr_file_t* pipe):
+		mDesc(desc),
+		mPipe(pipe),
+		// Essential to initialize our std::ostream with our special streambuf!
+		mStream(&mStreambuf)
+	{
+		mConnection = LLEventPumps::instance().obtain("mainloop")
+			.listen(LLEventPump::inventName("WritePipe"),
+					boost::bind(&WritePipeImpl::tick, this, _1));
+	}
+
+	virtual std::ostream& get_ostream() { return mStream; }
+
+	bool tick(const LLSD&)
+	{
+		typedef boost::asio::streambuf::const_buffers_type const_buffer_sequence;
+		// If there's anything to send, try to send it.
+		std::size_t total(mStreambuf.size()), consumed(0);
+		if (total)
+		{
+			const_buffer_sequence bufs = mStreambuf.data();
+			// In general, our streambuf might contain a number of different
+			// physical buffers; iterate over those.
+			for (const_buffer_sequence::const_iterator bufi(bufs.begin()), bufend(bufs.end());
+				 bufi != bufend; ++bufi)
+			{
+				// http://www.boost.org/doc/libs/1_49_0_beta1/doc/html/boost_asio/reference/buffer.html#boost_asio.reference.buffer.accessing_buffer_contents
+				std::size_t towrite(boost::asio::buffer_size(*bufi));
+				apr_size_t written(towrite);
+				apr_status_t err = apr_file_write(mPipe,
+												  boost::asio::buffer_cast<const void*>(*bufi),
+												  &written);
+				// EAGAIN is exactly what we want from a nonblocking pipe.
+				// Rather than waiting for data, it should return immediately.
+				if (! (err == APR_SUCCESS || APR_STATUS_IS_EAGAIN(err)))
+				{
+					LL_WARNS("LLProcess") << "apr_file_write(" << towrite << ") on " << mDesc
+										  << " got " << err << ":" << LL_ENDL;
+					ll_apr_warn_status(err);
+				}
+
+				// 'written' is modified to reflect the number of bytes actually
+				// written. Make sure we consume those later. (Don't consume them
+				// now, that would invalidate the buffer iterator sequence!)
+				consumed += written;
+				LL_DEBUGS("LLProcess") << "wrote " << written << " of " << towrite
+									   << " bytes to " << mDesc
+									   << " (original " << total << ")" << LL_ENDL;
+
+				// The parent end of this pipe is nonblocking. If we weren't able
+				// to write everything we wanted, don't keep banging on it -- that
+				// won't change until the child reads some. Wait for next tick().
+				if (written < towrite)
+					break;
+			}
+			// In all, we managed to write 'consumed' bytes. Remove them from the
+			// streambuf so we don't keep trying to send them. This could be
+			// anywhere from 0 up to mStreambuf.size(); anything we haven't yet
+			// sent, we'll try again later.
+			mStreambuf.consume(consumed);
+		}
+
+		return false;
+	}
+
+private:
+	std::string mDesc;
+	apr_file_t* mPipe;
+	LLTempBoundListener mConnection;
+	boost::asio::streambuf mStreambuf;
+	std::ostream mStream;
+};
+
+class ReadPipeImpl: public LLProcess::ReadPipe
+{
+	LOG_CLASS(ReadPipeImpl);
+public:
+	ReadPipeImpl(const std::string& desc, apr_file_t* pipe, LLProcess::FILESLOT index):
+		mDesc(desc),
+		mPipe(pipe),
+		mIndex(index),
+		// Essential to initialize our std::istream with our special streambuf!
+		mStream(&mStreambuf),
+		mPump("ReadPipe", true),    // tweak name as needed to avoid collisions
+		mLimit(0)
+	{
+		mConnection = LLEventPumps::instance().obtain("mainloop")
+			.listen(LLEventPump::inventName("ReadPipe"),
+					boost::bind(&ReadPipeImpl::tick, this, _1));
+	}
+
+	// Much of the implementation is simply connecting the abstract virtual
+	// methods with implementation data concealed from the base class.
+	virtual std::istream& get_istream() { return mStream; }
+	virtual LLEventPump& getPump() { return mPump; }
+	virtual void setLimit(size_type limit) { mLimit = limit; }
+	virtual size_type getLimit() const { return mLimit; }
+	virtual size_type size() const { return mStreambuf.size(); }
+
+	virtual std::string peek(size_type offset=0, size_type len=npos) const
+	{
+		// Constrain caller's offset and len to overlap actual buffer content.
+		std::size_t real_offset = (std::min)(mStreambuf.size(), std::size_t(offset));
+		size_type	want_end	= (len == npos)? npos : (real_offset + len);
+		std::size_t real_end	= (std::min)(mStreambuf.size(), std::size_t(want_end));
+		boost::asio::streambuf::const_buffers_type cbufs = mStreambuf.data();
+		return std::string(boost::asio::buffers_begin(cbufs) + real_offset,
+						   boost::asio::buffers_begin(cbufs) + real_end);
+	}
+
+	virtual size_type find(const std::string& seek, size_type offset=0) const
+	{
+		// If we're passing a string of length 1, use find(char), which can
+		// use an O(n) std::find() rather than the O(n^2) std::search().
+		if (seek.length() == 1)
+		{
+			return find(seek[0], offset);
+		}
+
+		// If offset is beyond the whole buffer, can't even construct a valid
+		// iterator range; can't possibly find the string we seek.
+		if (offset > mStreambuf.size())
+		{
+			return npos;
+		}
+
+		boost::asio::streambuf::const_buffers_type cbufs = mStreambuf.data();
+		boost::asio::buffers_iterator<boost::asio::streambuf::const_buffers_type>
+			begin(boost::asio::buffers_begin(cbufs)),
+			end	 (boost::asio::buffers_end(cbufs)),
+			found(std::search(begin + offset, end, seek.begin(), seek.end()));
+		return (found == end)? npos : (found - begin);
+	}
+
+	virtual size_type find(char seek, size_type offset=0) const
+	{
+		// If offset is beyond the whole buffer, can't even construct a valid
+		// iterator range; can't possibly find the char we seek.
+		if (offset > mStreambuf.size())
+		{
+			return npos;
+		}
+
+		boost::asio::streambuf::const_buffers_type cbufs = mStreambuf.data();
+		boost::asio::buffers_iterator<boost::asio::streambuf::const_buffers_type>
+			begin(boost::asio::buffers_begin(cbufs)),
+			end	 (boost::asio::buffers_end(cbufs)),
+			found(std::find(begin + offset, end, seek));
+		return (found == end)? npos : (found - begin);
+	}
+
+private:
+	bool tick(const LLSD&)
+	{
+		typedef boost::asio::streambuf::mutable_buffers_type mutable_buffer_sequence;
+		// Try, every time, to read into our streambuf. In fact, we have no
+		// idea how much data the child might be trying to send: keep trying
+		// until we're convinced we've temporarily exhausted the pipe.
+		bool exhausted = false;
+		std::size_t committed(0);
+		do
+		{
+			// attempt to read an arbitrary size
+			mutable_buffer_sequence bufs = mStreambuf.prepare(4096);
+			// In general, the mutable_buffer_sequence returned by prepare() might
+			// contain a number of different physical buffers; iterate over those.
+			std::size_t tocommit(0);
+			for (mutable_buffer_sequence::const_iterator bufi(bufs.begin()), bufend(bufs.end());
+				 bufi != bufend; ++bufi)
+			{
+				// http://www.boost.org/doc/libs/1_49_0_beta1/doc/html/boost_asio/reference/buffer.html#boost_asio.reference.buffer.accessing_buffer_contents
+				std::size_t toread(boost::asio::buffer_size(*bufi));
+				apr_size_t gotten(toread);
+				apr_status_t err = apr_file_read(mPipe,
+												 boost::asio::buffer_cast<void*>(*bufi),
+												 &gotten);
+				// EAGAIN is exactly what we want from a nonblocking pipe.
+				// Rather than waiting for data, it should return immediately.
+				if (! (err == APR_SUCCESS || APR_STATUS_IS_EAGAIN(err)))
+				{
+					// Handle EOF specially: it's part of normal-case processing.
+					if (err == APR_EOF)
+					{
+						LL_DEBUGS("LLProcess") << "EOF on " << mDesc << LL_ENDL;
+					}
+					else
+					{
+						LL_WARNS("LLProcess") << "apr_file_read(" << toread << ") on " << mDesc
+											  << " got " << err << ":" << LL_ENDL;
+						ll_apr_warn_status(err);
+					}
+					// Either way, though, we won't need any more tick() calls.
+					mConnection.disconnect();
+					exhausted = true; // also break outer retry loop
+					break;
+				}
+
+				// 'gotten' was modified to reflect the number of bytes actually
+				// received. Make sure we commit those later. (Don't commit them
+				// now, that would invalidate the buffer iterator sequence!)
+				tocommit += gotten;
+				LL_DEBUGS("LLProcess") << "read " << gotten << " of " << toread
+									   << " bytes from " << mDesc << LL_ENDL;
+
+				// The parent end of this pipe is nonblocking. If we weren't even
+				// able to fill this buffer, don't loop to try to fill the next --
+				// that won't change until the child writes more. Wait for next
+				// tick().
+				if (gotten < toread)
+				{
+					// break outer retry loop too
+					exhausted = true;
+					break;
+				}
+			}
+
+			// Don't forget to "commit" the data!
+			mStreambuf.commit(tocommit);
+			committed += tocommit;
+
+			// 'exhausted' is set when we can't fill any one buffer of the
+			// mutable_buffer_sequence established by the current prepare()
+			// call -- whether due to error or not enough bytes. That is,
+			// 'exhausted' is still false when we've filled every physical
+			// buffer in the mutable_buffer_sequence. In that case, for all we
+			// know, the child might have still more data pending -- go for it!
+		} while (! exhausted);
+
+		if (committed)
+		{
+			// If we actually received new data, publish it on our LLEventPump
+			// as advertised. Constrain it by mLimit. But show listener the
+			// actual accumulated buffer size, regardless of mLimit.
+			size_type datasize((std::min)(mLimit, size_type(mStreambuf.size())));
+			mPump.post(LLSDMap
+					   ("data", peek(0, datasize))
+					   ("len", LLSD::Integer(mStreambuf.size()))
+					   ("index", LLSD::Integer(mIndex))
+					   ("name", whichfile(mIndex))
+					   ("desc", mDesc));
+		}
+
+		return false;
+	}
+
+	std::string mDesc;
+	apr_file_t* mPipe;
+	LLProcess::FILESLOT mIndex;
+	LLTempBoundListener mConnection;
+	boost::asio::streambuf mStreambuf;
+	std::istream mStream;
+	LLEventStream mPump;
+	size_type mLimit;
+};
+
+/// Need an exception to avoid constructing an invalid LLProcess object, but
+/// internal use only
+struct LLProcessError: public std::runtime_error
+{
+	LLProcessError(const std::string& msg): std::runtime_error(msg) {}
+};
+
+LLProcessPtr LLProcess::create(const LLSDOrParams& params)
+{
+	try
+	{
+		return LLProcessPtr(new LLProcess(params));
+	}
+	catch (const LLProcessError& e)
+	{
+		LL_WARNS("LLProcess") << e.what() << LL_ENDL;
+
+		// If caller is requesting an event on process termination, send one
+		// indicating bad launch. This may prevent someone waiting forever for
+		// a termination post that can't arrive because the child never
+		// started.
+		if (params.postend.isProvided())
+		{
+			LLEventPumps::instance().obtain(params.postend)
+				.post(LLSDMap
+					  // no "id"
+					  ("desc", getDesc(params))
+					  ("state", LLProcess::UNSTARTED)
+					  // no "data"
+					  ("string", e.what())
+					 );
+		}
+
+		return LLProcessPtr();
+	}
+}
+
+/// Call an apr function returning apr_status_t. On failure, log warning and
+/// throw LLProcessError mentioning the function call that produced that
+/// result.
+#define chkapr(func)                            \
+	if (ll_apr_warn_status(func))				\
+		throw LLProcessError(#func " failed")
+
+LLProcess::LLProcess(const LLSDOrParams& params):
+	mAutokill(params.autokill),
+	mPipes(NSLOTS)
+{
+	// Hmm, when you construct a ptr_vector with a size, it merely reserves
+	// space, it doesn't actually make it that big. Explicitly make it bigger.
+	// Because of ptr_vector's odd semantics, have to push_back(0) the right
+	// number of times! resize() wants to default-construct new BasePipe
+	// instances, which fails because it's pure virtual. But because of the
+	// constructor call, these push_back() calls should require no new
+	// allocation.
+	for (size_t i = 0; i < mPipes.capacity(); ++i)
+		mPipes.push_back(0);
+
+	if (! params.validateBlock(true))
+	{
+		throw LLProcessError(STRINGIZE("not launched: failed parameter validation\n"
+									   << LLSDNotationStreamer(params)));
+	}
+
+	mPostend = params.postend;
+
+	apr_procattr_t *procattr = NULL;
+	chkapr(apr_procattr_create(&procattr, gAPRPoolp));
+
+	// For which of stdin, stdout, stderr should we create a pipe to the
+	// child? In the viewer, there are only a couple viable
+	// apr_procattr_io_set() alternatives: inherit the viewer's own stdxxx
+	// handle (APR_NO_PIPE, e.g. for stdout, stderr), or create a pipe that's
+	// blocking on the child end but nonblocking at the viewer end
+	// (APR_CHILD_BLOCK).
+	// Other major options could include explicitly creating a single APR pipe
+	// and passing it as both stdout and stderr (apr_procattr_child_out_set(),
+	// apr_procattr_child_err_set()), or accepting a filename, opening it and
+	// passing that apr_file_t (simple <, >, 2> redirect emulation).
+	std::vector<apr_int32_t> select;
+	BOOST_FOREACH(const FileParam& fparam, params.files)
+	{
+		// Every iteration, we're going to append an item to 'select'. At the
+		// top of the loop, its size() is, in effect, an index. Use that to
+		// pick a string description for messages.
+		std::string which(whichfile(FILESLOT(select.size())));
+		if (fparam.type().empty())  // inherit our file descriptor
+		{
+			select.push_back(APR_NO_PIPE);
+		}
+		else if (fparam.type() == "pipe") // anonymous pipe
+		{
+			if (! fparam.name().empty())
+			{
+				LL_WARNS("LLProcess") << "For " << params.executable()
+									  << ": internal names for reusing pipes ('"
+									  << fparam.name() << "' for " << which
+									  << ") are not yet supported -- creating distinct pipe"
+									  << LL_ENDL;
+			}
+			// The viewer can't block for anything: the parent end MUST be
+			// nonblocking. As the APR documentation itself points out, it
+			// makes very little sense to set nonblocking I/O for the child
+			// end of a pipe: only a specially-written child could deal with
+			// that.
+			select.push_back(APR_CHILD_BLOCK);
+		}
+		else
+		{
+			throw LLProcessError(STRINGIZE("For " << params.executable()
+										   << ": unsupported FileParam for " << which
+										   << ": type='" << fparam.type()
+										   << "', name='" << fparam.name() << "'"));
+		}
+	}
+	// By default, pass APR_NO_PIPE for unspecified slots.
+	while (select.size() < NSLOTS)
+	{
+		select.push_back(APR_NO_PIPE);
+	}
+	chkapr(apr_procattr_io_set(procattr, select[STDIN], select[STDOUT], select[STDERR]));
+
+	// Thumbs down on implicitly invoking the shell to invoke the child. From
+	// our point of view, the other major alternative to APR_PROGRAM_PATH
+	// would be APR_PROGRAM_ENV: still copy environment, but require full
+	// executable pathname. I don't see a downside to searching the PATH,
+	// though: if our caller wants (e.g.) a specific Python interpreter, s/he
+	// can still pass the full pathname.
+	chkapr(apr_procattr_cmdtype_set(procattr, APR_PROGRAM_PATH));
+	// YES, do extra work if necessary to report child exec() failures back to
+	// parent process.
+	chkapr(apr_procattr_error_check_set(procattr, 1));
+	// Do not start a non-autokill child in detached state. On Posix
+	// platforms, this setting attempts to daemonize the new child, closing
+	// std handles and the like, and that's a bit more detachment than we
+	// want. autokill=false just means not to implicitly kill the child when
+	// the parent terminates!
+//	chkapr(apr_procattr_detach_set(procattr, params.autokill? 0 : 1));
+
+	if (params.autokill)
+	{
+#if defined(APR_HAS_PROCATTR_AUTOKILL_SET)
+		apr_status_t ok = apr_procattr_autokill_set(procattr, 1);
+# if LL_WINDOWS
+		// As of 2012-02-02, we only expect this to be implemented on Windows.
+		// Avoid spamming the log with warnings we fully expect.
+		ll_apr_warn_status(ok);
+#else   // ! LL_WINDOWS
+		(void)ok;                   // suppress 'unused' warning
+# endif // ! LL_WINDOWS
+#else
+		LL_WARNS("LLProcess") << "This version of APR lacks Linden apr_procattr_autokill_set() extension" << LL_ENDL;
+#endif
+	}
+
+	// In preparation for calling apr_proc_create(), we collect a number of
+	// const char* pointers obtained from std::string::c_str(). Turns out
+	// LLInitParam::Block's helpers Optional, Mandatory, Multiple et al.
+	// guarantee that converting to the wrapped type (std::string in our
+	// case), e.g. by calling operator(), returns a reference to *the same
+	// instance* of the wrapped type that's stored in our Block subclass.
+	// That's important! We know 'params' persists throughout this method
+	// call; but without that guarantee, we'd have to assume that converting
+	// one of its members to std::string might return a different (temp)
+	// instance. Capturing the c_str() from a temporary std::string is Bad Bad
+	// Bad. But armed with this knowledge, when you see params.cwd().c_str(),
+	// grit your teeth and smile and carry on.
+
+	if (params.cwd.isProvided())
+	{
+		chkapr(apr_procattr_dir_set(procattr, params.cwd().c_str()));
+	}
+
+	// create an argv vector for the child process
+	std::vector<const char*> argv;
+
+	// Add the executable path. See above remarks about c_str().
+	argv.push_back(params.executable().c_str());
+
+	// Add arguments. See above remarks about c_str().
+	BOOST_FOREACH(const std::string& arg, params.args)
+	{
+		argv.push_back(arg.c_str());
+	}
+
+	// terminate with a null pointer
+	argv.push_back(NULL);
+
+	// Launch! The NULL would be the environment block, if we were passing one.
+	chkapr(apr_proc_create(&mProcess, argv[0], &argv[0], NULL, procattr, gAPRPoolp));    
+
+	// arrange to call status_callback()
+	apr_proc_other_child_register(&mProcess, &LLProcess::status_callback, this, mProcess.in,
+								  gAPRPoolp);
+	// and make sure we poll it once per "mainloop" tick
+	sProcessListener.addPoll(*this);
+	mStatus.mState = RUNNING;
+
+	mDesc = STRINGIZE(getDesc(params) << " (" << mProcess.pid << ')');
+	LL_INFOS("LLProcess") << mDesc << ": launched " << params << LL_ENDL;
+
+	// Unless caller explicitly turned off autokill (child should persist),
+	// take steps to terminate the child. This is all suspenders-and-belt: in
+	// theory our destructor should kill an autokill child, but in practice
+	// that doesn't always work (e.g. VWR-21538).
+	if (params.autokill)
+	{
+		// Tie the lifespan of this child process to the lifespan of our APR
+		// pool: on destruction of the pool, forcibly kill the process. Tell
+		// APR to try SIGTERM and wait 3 seconds. If that didn't work, use
+		// SIGKILL.
+		apr_pool_note_subprocess(gAPRPoolp, &mProcess, APR_KILL_AFTER_TIMEOUT);
+
+		// On Windows, associate the new child process with our Job Object.
+		autokill();
+	}
+
+	// Instantiate the proper pipe I/O machinery
+	// want to be able to point to apr_proc_t::in, out, err by index
+	typedef apr_file_t* apr_proc_t::*apr_proc_file_ptr;
+	static apr_proc_file_ptr members[] =
+		{ &apr_proc_t::in, &apr_proc_t::out, &apr_proc_t::err };
+	for (size_t i = 0; i < NSLOTS; ++i)
+	{
+		if (select[i] != APR_CHILD_BLOCK)
+			continue;
+		std::string desc(STRINGIZE(mDesc << ' ' << whichfile(FILESLOT(i))));
+		apr_file_t* pipe(mProcess.*(members[i]));
+		if (i == STDIN)
+		{
+			mPipes.replace(i, new WritePipeImpl(desc, pipe));
+		}
+		else
+		{
+			mPipes.replace(i, new ReadPipeImpl(desc, pipe, FILESLOT(i)));
+		}
+		LL_DEBUGS("LLProcess") << "Instantiating " << typeid(mPipes[i]).name()
+							   << "('" << desc << "')" << LL_ENDL;
+	}
+}
+
+// Helper to obtain a description string, given a Params block
+static std::string getDesc(const LLProcess::Params& params)
+{
+	// If caller specified a description string, by all means use it.
+	if (params.desc.isProvided())
+		return params.desc;
+
+	// Caller didn't say. Use the executable name -- but use just the filename
+	// part. On Mac, for instance, full pathnames get cumbersome.
+	// If there are Linden utility functions to manipulate pathnames, I
+	// haven't found them -- and for this usage, Boost.Filesystem seems kind
+	// of heavyweight.
+	std::string executable(params.executable);
+	std::string::size_type delim = executable.find_last_of("\\/");
+	// If executable contains no pathname delimiters, return the whole thing.
+	if (delim == std::string::npos)
+		return executable;
+
+	// Return just the part beyond the last delimiter.
+	return executable.substr(delim + 1);
+}
+
+LLProcess::~LLProcess()
+{
+	// Only in state RUNNING are we registered for callback. In UNSTARTED we
+	// haven't yet registered. And since receiving the callback is the only
+	// way we detect child termination, we only change from state RUNNING at
+	// the same time we unregister.
+	if (mStatus.mState == RUNNING)
+	{
+		// We're still registered for a callback: unregister. Do it before
+		// we even issue the kill(): even if kill() somehow prompted an
+		// instantaneous callback (unlikely), this object is going away! Any
+		// information updated in this object by such a callback is no longer
+		// available to any consumer anyway.
+		apr_proc_other_child_unregister(this);
+		// One less LLProcess to poll for
+		sProcessListener.dropPoll(*this);
+	}
+
+	if (mAutokill)
+	{
+		kill("destructor");
+	}
+}
+
+bool LLProcess::kill(const std::string& who)
+{
+	if (isRunning())
+	{
+		LL_INFOS("LLProcess") << who << " killing " << mDesc << LL_ENDL;
+
+#if LL_WINDOWS
+		int sig = -1;
+#else  // Posix
+		int sig = SIGTERM;
+#endif
+
+		ll_apr_warn_status(apr_proc_kill(&mProcess, sig));
+	}
+
+	return ! isRunning();
+}
+
+bool LLProcess::isRunning() const
+{
+	return getStatus().mState == RUNNING;
+}
+
+LLProcess::Status LLProcess::getStatus() const
+{
+	return mStatus;
+}
+
+std::string LLProcess::getStatusString() const
+{
+	return getStatusString(getStatus());
+}
+
+std::string LLProcess::getStatusString(const Status& status) const
+{
+	return getStatusString(mDesc, status);
+}
+
+//static
+std::string LLProcess::getStatusString(const std::string& desc, const Status& status)
+{
+	if (status.mState == UNSTARTED)
+		return desc + " was never launched";
+
+	if (status.mState == RUNNING)
+		return desc + " running";
+
+	if (status.mState == EXITED)
+		return STRINGIZE(desc << " exited with code " << status.mData);
+
+	if (status.mState == KILLED)
+#if LL_WINDOWS
+		return STRINGIZE(desc << " killed with exception " << std::hex << status.mData);
+#else
+		return STRINGIZE(desc << " killed by signal " << status.mData
+						 << " (" << apr_signal_description_get(status.mData) << ")");
+#endif
+
+	return STRINGIZE(desc << " in unknown state " << status.mState << " (" << status.mData << ")");
+}
+
+// Classic-C-style APR callback
+void LLProcess::status_callback(int reason, void* data, int status)
+{
+	// Our only role is to bounce this static method call back into object
+	// space.
+	static_cast<LLProcess*>(data)->handle_status(reason, status);
+}
+
+#define tabent(symbol) { symbol, #symbol }
+static struct ReasonCode
+{
+	int code;
+	const char* name;
+} reasons[] =
+{
+	tabent(APR_OC_REASON_DEATH),
+	tabent(APR_OC_REASON_UNWRITABLE),
+	tabent(APR_OC_REASON_RESTART),
+	tabent(APR_OC_REASON_UNREGISTER),
+	tabent(APR_OC_REASON_LOST),
+	tabent(APR_OC_REASON_RUNNING)
+};
+#undef tabent
+
+// Object-oriented callback
+void LLProcess::handle_status(int reason, int status)
+{
+	{
+		// This odd appearance of LL_DEBUGS is just to bracket a lookup that will
+		// only be performed if in fact we're going to produce the log message.
+		LL_DEBUGS("LLProcess") << empty;
+		std::string reason_str;
+		BOOST_FOREACH(const ReasonCode& rcp, reasons)
+		{
+			if (reason == rcp.code)
+			{
+				reason_str = rcp.name;
+				break;
+			}
+		}
+		if (reason_str.empty())
+		{
+			reason_str = STRINGIZE("unknown reason " << reason);
+		}
+		LL_CONT << mDesc << ": handle_status(" << reason_str << ", " << status << ")" << LL_ENDL;
+	}
+
+	if (! (reason == APR_OC_REASON_DEATH || reason == APR_OC_REASON_LOST))
+	{
+		// We're only interested in the call when the child terminates.
+		return;
+	}
+
+	// Somewhat oddly, APR requires that you explicitly unregister even when
+	// it already knows the child has terminated. We must pass the same 'data'
+	// pointer as for the register() call, which was our 'this'.
+	apr_proc_other_child_unregister(this);
+	// don't keep polling for a terminated process
+	sProcessListener.dropPoll(*this);
+	// We overload mStatus.mState to indicate whether the child is registered
+	// for APR callback: only RUNNING means registered. Track that we've
+	// unregistered. We know the child has terminated; might be EXITED or
+	// KILLED; refine below.
+	mStatus.mState = EXITED;
+
+//	wi->rv = apr_proc_wait(wi->child, &wi->rc, &wi->why, APR_NOWAIT);
+	// It's just wrong to call apr_proc_wait() here. The only way APR knows to
+	// call us with APR_OC_REASON_DEATH is that it's already reaped this child
+	// process, so calling wait() will only produce "huh?" from the OS. We
+	// must rely on the status param passed in, which unfortunately comes
+	// straight from the OS wait() call, which means we have to decode it by
+	// hand.
+	mStatus = interpret_status(status);
+	LL_INFOS("LLProcess") << getStatusString() << LL_ENDL;
+
+	// If caller requested notification on child termination, send it.
+	if (! mPostend.empty())
+	{
+		LLEventPumps::instance().obtain(mPostend)
+			.post(LLSDMap
+				  ("id",     getProcessID())
+				  ("desc",   mDesc)
+				  ("state",  mStatus.mState)
+				  ("data",   mStatus.mData)
+				  ("string", getStatusString())
+				 );
+	}
+}
+
+LLProcess::id LLProcess::getProcessID() const
+{
+	return mProcess.pid;
+}
+
+LLProcess::handle LLProcess::getProcessHandle() const
+{
+#if LL_WINDOWS
+	return mProcess.hproc;
+#else
+	return mProcess.pid;
+#endif
+}
+
+std::string LLProcess::getPipeName(FILESLOT) const
+{
+	// LLProcess::FileParam::type "npipe" is not yet implemented
+	return "";
+}
+
+template<class PIPETYPE>
+PIPETYPE* LLProcess::getPipePtr(std::string& error, FILESLOT slot)
+{
+	if (slot >= NSLOTS)
+	{
+		error = STRINGIZE(mDesc << " has no slot " << slot);
+		return NULL;
+	}
+	if (mPipes.is_null(slot))
+	{
+		error = STRINGIZE(mDesc << ' ' << whichfile(slot) << " not a monitored pipe");
+		return NULL;
+	}
+	// Make sure we dynamic_cast in pointer domain so we can test, rather than
+	// accepting runtime's exception.
+	PIPETYPE* ppipe = dynamic_cast<PIPETYPE*>(&mPipes[slot]);
+	if (! ppipe)
+	{
+		error = STRINGIZE(mDesc << ' ' << whichfile(slot) << " not a " << typeid(PIPETYPE).name());
+		return NULL;
+	}
+
+	error.clear();
+	return ppipe;
+}
+
+template <class PIPETYPE>
+PIPETYPE& LLProcess::getPipe(FILESLOT slot)
+{
+	std::string error;
+	PIPETYPE* wp = getPipePtr<PIPETYPE>(error, slot);
+	if (! wp)
+	{
+		throw NoPipe(error);
+	}
+	return *wp;
+}
+
+template <class PIPETYPE>
+boost::optional<PIPETYPE&> LLProcess::getOptPipe(FILESLOT slot)
+{
+	std::string error;
+	PIPETYPE* wp = getPipePtr<PIPETYPE>(error, slot);
+	if (! wp)
+	{
+		LL_DEBUGS("LLProcess") << error << LL_ENDL;
+		return boost::optional<PIPETYPE&>();
+	}
+	return *wp;
+}
+
+LLProcess::WritePipe& LLProcess::getWritePipe(FILESLOT slot)
+{
+	return getPipe<WritePipe>(slot);
+}
+
+boost::optional<LLProcess::WritePipe&> LLProcess::getOptWritePipe(FILESLOT slot)
+{
+	return getOptPipe<WritePipe>(slot);
+}
+
+LLProcess::ReadPipe& LLProcess::getReadPipe(FILESLOT slot)
+{
+	return getPipe<ReadPipe>(slot);
+}
+
+boost::optional<LLProcess::ReadPipe&> LLProcess::getOptReadPipe(FILESLOT slot)
+{
+	return getOptPipe<ReadPipe>(slot);
+}
+
+std::ostream& operator<<(std::ostream& out, const LLProcess::Params& params)
+{
+	if (params.cwd.isProvided())
+	{
+		out << "cd " << LLStringUtil::quote(params.cwd) << ": ";
+	}
+	out << LLStringUtil::quote(params.executable);
+	BOOST_FOREACH(const std::string& arg, params.args)
+	{
+		out << ' ' << LLStringUtil::quote(arg);
+	}
+	return out;
+}
+
+/*****************************************************************************
+*   Windows specific
+*****************************************************************************/
+#if LL_WINDOWS
+
+static std::string WindowsErrorString(const std::string& operation);
+
+void LLProcess::autokill()
+{
+	// hopefully now handled by apr_procattr_autokill_set()
+}
+
+LLProcess::handle LLProcess::isRunning(handle h, const std::string& desc)
+{
+	// This direct Windows implementation is because we have no access to the
+	// apr_proc_t struct: we expect it's been destroyed.
+	if (! h)
+		return 0;
+
+	DWORD waitresult = WaitForSingleObject(h, 0);
+	if(waitresult == WAIT_OBJECT_0)
+	{
+		// the process has completed.
+		if (! desc.empty())
+		{
+			DWORD status = 0;
+			if (! GetExitCodeProcess(h, &status))
+			{
+				LL_WARNS("LLProcess") << desc << " terminated, but "
+									  << WindowsErrorString("GetExitCodeProcess()") << LL_ENDL;
+			}
+			{
+				LL_INFOS("LLProcess") << getStatusString(desc, interpret_status(status))
+									  << LL_ENDL;
+			}
+		}
+		CloseHandle(h);
+		return 0;
+	}
+
+	return h;
+}
+
+static LLProcess::Status interpret_status(int status)
+{
+	LLProcess::Status result;
+
+	// This bit of code is cribbed from apr/threadproc/win32/proc.c, a
+	// function (unfortunately static) called why_from_exit_code():
+	/* See WinNT.h STATUS_ACCESS_VIOLATION and family for how
+	 * this class of failures was determined
+	 */
+	if ((status & 0xFFFF0000) == 0xC0000000)
+	{
+		result.mState = LLProcess::KILLED;
+	}
+	else
+	{
+		result.mState = LLProcess::EXITED;
+	}
+	result.mData = status;
+
+	return result;
+}
+
+/// GetLastError()/FormatMessage() boilerplate
+static std::string WindowsErrorString(const std::string& operation)
+{
+	int result = GetLastError();
+
+	LPTSTR error_str = 0;
+	if (FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
+					   NULL,
+					   result,
+					   0,
+					   (LPTSTR)&error_str,
+					   0,
+					   NULL)
+		!= 0) 
+	{
+		// convert from wide-char string to multi-byte string
+		char message[256];
+		wcstombs(message, error_str, sizeof(message));
+		message[sizeof(message)-1] = 0;
+		LocalFree(error_str);
+		// convert to std::string to trim trailing whitespace
+		std::string mbsstr(message);
+		mbsstr.erase(mbsstr.find_last_not_of(" \t\r\n"));
+		return STRINGIZE(operation << " failed (" << result << "): " << mbsstr);
+	}
+	return STRINGIZE(operation << " failed (" << result
+					 << "), but FormatMessage() did not explain");
+}
+
+/*****************************************************************************
+*   Posix specific
+*****************************************************************************/
+#else // Mac and linux
+
+#include <signal.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/wait.h>
+
+void LLProcess::autokill()
+{
+	// What we ought to do here is to:
+	// 1. create a unique process group and run all autokill children in that
+	//    group (see https://jira.secondlife.com/browse/SWAT-563);
+	// 2. figure out a way to intercept control when the viewer exits --
+	//    gracefully or not; 
+	// 3. when the viewer exits, kill off the aforementioned process group.
+
+	// It's point 2 that's troublesome. Although I've seen some signal-
+	// handling logic in the Posix viewer code, I haven't yet found any bit of
+	// code that's run no matter how the viewer exits (a try/finally for the
+	// whole process, as it were).
+}
+
+// Attempt to reap a process ID -- returns true if the process has exited and been reaped, false otherwise.
+static bool reap_pid(pid_t pid, LLProcess::Status* pstatus=NULL)
+{
+	LLProcess::Status dummy;
+	if (! pstatus)
+	{
+		// If caller doesn't want to see Status, give us a target anyway so we
+		// don't have to have a bunch of conditionals.
+		pstatus = &dummy;
+	}
+
+	int status = 0;
+	pid_t wait_result = ::waitpid(pid, &status, WNOHANG);
+	if (wait_result == pid)
+	{
+		*pstatus = interpret_status(status);
+		return true;
+	}
+	if (wait_result == 0)
+	{
+		pstatus->mState = LLProcess::RUNNING;
+		pstatus->mData	= 0;
+		return false;
+	}
+
+	// Clear caller's Status block; caller must interpret UNSTARTED to mean
+	// "if this PID was ever valid, it no longer is."
+	*pstatus = LLProcess::Status();
+
+	// We've dealt with the success cases: we were able to reap the child
+	// (wait_result == pid) or it's still running (wait_result == 0). It may
+	// be that the child terminated but didn't hang around long enough for us
+	// to reap. In that case we still have no Status to report, but we can at
+	// least state that it's not running.
+	if (wait_result == -1 && errno == ECHILD)
+	{
+		// No such process -- this may mean we're ignoring SIGCHILD.
+		return true;
+	}
+
+	// Uh, should never happen?!
+	LL_WARNS("LLProcess") << "LLProcess::reap_pid(): waitpid(" << pid << ") returned "
+						  << wait_result << "; not meaningful?" << LL_ENDL;
+	// If caller is looping until this pid terminates, and if we can't find
+	// out, better to break the loop than to claim it's still running.
+	return true;
+}
+
+LLProcess::id LLProcess::isRunning(id pid, const std::string& desc)
+{
+	// This direct Posix implementation is because we have no access to the
+	// apr_proc_t struct: we expect it's been destroyed.
+	if (! pid)
+		return 0;
+
+	// Check whether the process has exited, and reap it if it has.
+	LLProcess::Status status;
+	if(reap_pid(pid, &status))
+	{
+		// the process has exited.
+		if (! desc.empty())
+		{
+			std::string statstr(desc + " apparently terminated: no status available");
+			// We don't just pass UNSTARTED to getStatusString() because, in
+			// the context of reap_pid(), that state has special meaning.
+			if (status.mState != UNSTARTED)
+			{
+				statstr = getStatusString(desc, status);
+			}
+			LL_INFOS("LLProcess") << statstr << LL_ENDL;
+		}
+		return 0;
+	}
+
+	return pid;
+}
+
+static LLProcess::Status interpret_status(int status)
+{
+	LLProcess::Status result;
+
+	if (WIFEXITED(status))
+	{
+		result.mState = LLProcess::EXITED;
+		result.mData  = WEXITSTATUS(status);
+	}
+	else if (WIFSIGNALED(status))
+	{
+		result.mState = LLProcess::KILLED;
+		result.mData  = WTERMSIG(status);
+	}
+	else                            // uh, shouldn't happen?
+	{
+		result.mState = LLProcess::EXITED;
+		result.mData  = status;     // someone else will have to decode
+	}
+
+	return result;
+}
+
+/*==========================================================================*|
+static std::list<pid_t> sZombies;
+
+void LLProcess::orphan(void)
+{
+	// Disassociate the process from this object
+	if(mProcessID != 0)
+	{	
+		// We may still need to reap the process's zombie eventually
+		sZombies.push_back(mProcessID);
+	
+		mProcessID = 0;
+	}
+}
+
+// static 
+void LLProcess::reap(void)
+{
+	// Attempt to real all saved process ID's.
+	
+	std::list<pid_t>::iterator iter = sZombies.begin();
+	while(iter != sZombies.end())
+	{
+		if(reap_pid(*iter))
+		{
+			iter = sZombies.erase(iter);
+		}
+		else
+		{
+			iter++;
+		}
+	}
+}
+|*==========================================================================*/
+#endif  // Posix