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Diffstat (limited to 'indra/llcommon/llprocess.cpp')
| -rw-r--r-- | indra/llcommon/llprocess.cpp | 1313 |
1 files changed, 1313 insertions, 0 deletions
diff --git a/indra/llcommon/llprocess.cpp b/indra/llcommon/llprocess.cpp new file mode 100644 index 0000000000..9667e4e033 --- /dev/null +++ b/indra/llcommon/llprocess.cpp @@ -0,0 +1,1313 @@ +/** + * @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> + +/***************************************************************************** +* Helpers +*****************************************************************************/ +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; + +/***************************************************************************** +* WritePipe and ReadPipe +*****************************************************************************/ +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)); + +#if ! LL_WINDOWS + // We can't count on every child process reading everything we try to + // write to it. And if the child terminates with WritePipe data still + // pending, unless we explicitly suppress it, Posix will hit us with + // SIGPIPE. That would terminate the viewer, boom. "Ignoring" it means + // APR gets the correct errno, passes it back to us, we log it, etc. + signal(SIGPIPE, SIG_IGN); +#endif + } + + virtual std::ostream& get_ostream() { return mStream; } + virtual size_type size() const { return mStreambuf.size(); } + + 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. + bool keepwriting = true; + for (const_buffer_sequence::const_iterator bufi(bufs.begin()), bufend(bufs.end()); + bufi != bufend && keepwriting; ++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 + // Although apr_file_write() accepts const void*, we + // manipulate const char* so we can increment the pointer. + const char* remainptr = boost::asio::buffer_cast<const char*>(*bufi); + std::size_t remainlen = boost::asio::buffer_size(*bufi); + while (remainlen) + { + // Tackle the current buffer in discrete chunks. On + // Windows, we've observed strange failures when trying to + // write big lengths (~1 MB) in a single operation. Even a + // 32K chunk seems too large. At some point along the way + // apr_file_write() returns 11 (Resource temporarily + // unavailable, i.e. EAGAIN) and says it wrote 0 bytes -- + // even though it did write the chunk! Our next write + // attempt retries with the same chunk, resulting in the + // chunk being duplicated at the child end. Using smaller + // chunks is empirically more reliable. + std::size_t towrite((std::min)(remainlen, std::size_t(4*1024))); + apr_size_t written(towrite); + apr_status_t err = apr_file_write(mPipe, remainptr, &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; + // don't forget to advance to next chunk of current buffer + remainptr += written; + remainlen -= written; + + char msgbuf[512]; + LL_DEBUGS("LLProcess") << "wrote " << written << " of " << towrite + << " bytes to " << mDesc + << " (original " << total << ")," + << " code " << err << ": " + << apr_strerror(err, msgbuf, sizeof(msgbuf)) + << 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) + { + keepwriting = false; // break outer loop over buffers too + break; + } + } // next chunk of current buffer + } // next buffer + // 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), + mEOF(false) + { + 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 std::string getline() { return LLProcess::getline(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 read(size_type len) + { + // Read specified number of bytes into a buffer. + size_type readlen((std::min)(size(), len)); + // Formally, &buffer[0] is invalid for a vector of size() 0. Exit + // early in that situation. + if (! readlen) + return ""; + // Make a buffer big enough. + std::vector<char> buffer(readlen); + mStream.read(&buffer[0], readlen); + // Since we've already clamped 'readlen', we can think of no reason + // why mStream.read() should read fewer than 'readlen' bytes. + // Nonetheless, use the actual retrieved length. + return std::string(&buffer[0], mStream.gcount()); + } + + 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); + } + + bool tick(const LLSD&) + { + // Once we've hit EOF, skip all the rest of this. + if (mEOF) + return false; + + 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. + enum PipeState { RETRY, EXHAUSTED, CLOSED }; + PipeState state = RETRY; + 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(); + // Ignore any subsequent calls we might get anyway. + mEOF = true; + state = CLOSED; // 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") << "filled " << 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 + state = EXHAUSTED; + break; + } + } + + // Don't forget to "commit" the data! + mStreambuf.commit(tocommit); + committed += tocommit; + + // state is changed from RETRY 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, if state is still RETRY, 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 (state == RETRY); + + // Once we recognize that the pipe is closed, make one more call to + // listener. The listener might be waiting for a particular substring + // to arrive, or a particular length of data or something. The event + // with "eof" == true announces that nothing further will arrive, so + // use it or lose it. + if (committed || state == CLOSED) + { + // 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())) + ("slot", LLSD::Integer(mIndex)) + ("name", whichfile(mIndex)) + ("desc", mDesc) + ("eof", state == CLOSED)); + } + + return false; + } + +private: + std::string mDesc; + apr_file_t* mPipe; + LLProcess::FILESLOT mIndex; + LLTempBoundListener mConnection; + boost::asio::streambuf mStreambuf; + std::istream mStream; + LLEventStream mPump; + size_type mLimit; + bool mEOF; +}; + +/***************************************************************************** +* LLProcess itself +*****************************************************************************/ +/// 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)); + + // IQA-490, CHOP-900: On Windows, ask APR to jump through hoops to + // constrain the set of handles passed to the child process. Before we + // changed to APR, the Windows implementation of LLProcessLauncher called + // CreateProcess(bInheritHandles=FALSE), meaning to pass NO open handles + // to the child process. Now that we support pipes, though, we must allow + // apr_proc_create() to pass bInheritHandles=TRUE. But without taking + // special pains, that causes trouble in a number of ways, due to the fact + // that the viewer is constantly opening and closing files -- most of + // which CreateProcess() passes to every child process! +#if ! defined(APR_HAS_PROCATTR_CONSTRAIN_HANDLE_SET) + // Our special preprocessor symbol isn't even defined -- wrong APR + LL_WARNS("LLProcess") << "This version of APR lacks Linden " + << "apr_procattr_constrain_handle_set() extension" << LL_ENDL; +#else + chkapr(apr_procattr_constrain_handle_set(procattr, 1)); +#endif + + // 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) + // Our special preprocessor symbol isn't even defined -- wrong APR + LL_WARNS("LLProcess") << "This version of APR lacks Linden apr_procattr_autokill_set() extension" << LL_ENDL; +#elif ! APR_HAS_PROCATTR_AUTOKILL_SET + // Symbol is defined, but to 0: expect apr_procattr_autokill_set() to + // return APR_ENOTIMPL. +#else // APR_HAS_PROCATTR_AUTOKILL_SET nonzero + ll_apr_warn_status(apr_procattr_autokill_set(procattr, 1)); +#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. Hand-expand chkapr() macro so we can fill in the actual command + // string instead of the variable names. + if (ll_apr_warn_status(apr_proc_create(&mProcess, argv[0], &argv[0], NULL, procattr, + gAPRPoolp))) + { + throw LLProcessError(STRINGIZE(params << " failed")); + } + + // 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) + { +/*==========================================================================*| + // NO: There may be an APR bug, not sure -- but at least on Mac, when + // gAPRPoolp is destroyed, OUR process receives SIGTERM! Apparently + // either our own PID is getting into the list of processes to kill() + // (unlikely), or somehow one of those PIDs is getting zeroed first, + // so that kill() sends SIGTERM to the whole process group -- this + // process included. I'd have to build and link with a debug version + // of APR to know for sure. It's too bad: this mechanism would be just + // right for dealing with static autokill LLProcessPtr variables, + // which aren't destroyed until after APR is no longer available. + + // 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. + return LLProcess::basename(params.executable); +} + +//static +std::string LLProcess::basename(const std::string& path) +{ + // 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::size_type delim = path.find_last_of("\\/"); + // If path contains no pathname delimiters, return the whole thing. + if (delim == std::string::npos) + return path; + + // Return just the part beyond the last delimiter. + return path.substr(delim + 1); +} + +LLProcess::~LLProcess() +{ + // In the Linden viewer, there's at least one static LLProcessPtr. Its + // destructor will be called *after* ll_cleanup_apr(). In such a case, + // unregistering is pointless (and fatal!) -- and kill(), which also + // relies on APR, is impossible. + if (! gAPRPoolp) + return; + + // 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; + + // Make last-gasp calls for each of the ReadPipes we have on hand. Since + // they're listening on "mainloop", we can be sure they'll eventually + // collect all pending data from the child. But we want to be able to + // guarantee to our consumer that by the time we post on the "postend" + // LLEventPump, our ReadPipes are already buffering all the data there + // will ever be from the child. That lets the "postend" listener decide + // what to do with that final data. + for (size_t i = 0; i < mPipes.size(); ++i) + { + std::string error; + ReadPipeImpl* ppipe = getPipePtr<ReadPipeImpl>(error, FILESLOT(i)); + if (ppipe) + { + static LLSD trivial; + ppipe->tick(trivial); + } + } + +// 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); +} + +//static +std::string LLProcess::getline(std::istream& in) +{ + std::string line; + std::getline(in, line); + // Blur the distinction between "\r\n" and plain "\n". std::getline() will + // have eaten the "\n", but we could still end up with a trailing "\r". + std::string::size_type lastpos = line.find_last_not_of("\r"); + if (lastpos != std::string::npos) + { + // Found at least one character that's not a trailing '\r'. SKIP OVER + // IT and erase the rest of the line. + line.erase(lastpos+1); + } + return line; +} + +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; +} + +#endif // Posix |