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Diffstat (limited to 'indra/llcommon/llprocess.cpp')
| -rw-r--r-- | indra/llcommon/llprocess.cpp | 642 |
1 files changed, 642 insertions, 0 deletions
diff --git a/indra/llcommon/llprocess.cpp b/indra/llcommon/llprocess.cpp new file mode 100644 index 0000000000..7ccbdeed01 --- /dev/null +++ b/indra/llcommon/llprocess.cpp @@ -0,0 +1,642 @@ +/** + * @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 "llsdserialize.h" +#include "llsingleton.h" +#include "llstring.h" +#include "stringize.h" +#include "llapr.h" +#include "apr_signal.h" + +#include <boost/foreach.hpp> +#include <iostream> +#include <stdexcept> + +static std::string empty; +static LLProcess::Status interpret_status(int status); + +/// 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; + 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) +{ + if (! params.validateBlock(true)) + { + throw LLProcessError(STRINGIZE("not launched: failed parameter validation\n" + << LLSDNotationStreamer(params))); + } + + 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). 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. + // 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). +// chkapr(apr_procattr_io_set(procattr, APR_CHILD_BLOCK, APR_CHILD_BLOCK, APR_CHILD_BLOCK)); + chkapr(apr_procattr_io_set(procattr, APR_NO_PIPE, APR_NO_PIPE, APR_NO_PIPE)); + + // 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); +# endif // LL_WINDOWS +#else + LL_WARNS("LLProcess") << "This version of APR lacks Linden apr_procattr_autokill_set() extension" << LL_ENDL; +#endif + } + + // Have to instantiate named std::strings for string params items so their + // c_str() values persist. + std::string cwd(params.cwd); + if (! cwd.empty()) + { + chkapr(apr_procattr_dir_set(procattr, cwd.c_str())); + } + + // create an argv vector for the child process + std::vector<const char*> argv; + + // add the executable path + std::string executable(params.executable); + argv.push_back(executable.c_str()); + + // and any arguments + std::vector<std::string> args(params.args.begin(), params.args.end()); + BOOST_FOREACH(const std::string& arg, 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); + mStatus.mState = RUNNING; + + mDesc = STRINGIZE(LLStringUtil::quote(params.executable) << " (" << mProcess.pid << ')'); + LL_INFOS("LLProcess") << "Launched " << params << " (" << mProcess.pid << ")" << 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(); + } +} + +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); + } + + 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(void) +{ + return getStatus().mState == RUNNING; +} + +LLProcess::Status LLProcess::getStatus() +{ + // Only when mState is RUNNING might the status change dynamically. For + // any other value, pointless to attempt to update status: it won't + // change. + if (mStatus.mState == RUNNING) + { + // Tell APR to sense whether the child 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 if I + // knew how. As it is, each call to this method will call callbacks + // for ALL still-running child processes. Sigh... + apr_proc_other_child_refresh_all(APR_OC_REASON_RUNNING); + } + + return mStatus; +} + +std::string LLProcess::getStatusString() +{ + return getStatusString(getStatus()); +} + +std::string LLProcess::getStatusString(const Status& status) +{ + 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); + // 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; +} + +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::ostream& operator<<(std::ostream& out, const LLProcess::Params& params) +{ + std::string cwd(params.cwd); + if (! cwd.empty()) + { + out << "cd " << LLStringUtil::quote(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 |