/* $Id: init.cpp 36549 2011-04-05 09:28:24Z vboxsync $ */
/** @file
 * IPRT - Init Ring-3.
 */

/*
 * Copyright (C) 2006-2009 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 */


/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/
#define LOG_GROUP RTLOGGROUP_DEFAULT
#include <iprt/types.h>                 /* darwin: UINT32_C and others. */

#ifdef RT_OS_WINDOWS
# include <process.h>
#else
# include <unistd.h>
# ifndef RT_OS_OS2
#  include <pthread.h>
#  include <signal.h>
#  include <errno.h>
#  define IPRT_USE_SIG_CHILD_DUMMY
# endif
#endif
#ifdef RT_OS_OS2
# include <InnoTekLIBC/fork.h>
#endif
#include <locale.h>

#include <iprt/initterm.h>
#include <iprt/asm.h>
#include <iprt/assert.h>
#include <iprt/err.h>
#include <iprt/log.h>
#include <iprt/path.h>
#include <iprt/time.h>
#include <iprt/string.h>
#include <iprt/param.h>
#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
# include <iprt/file.h>
# include <VBox/sup.h>
#endif
#include <stdlib.h>

#include "internal/alignmentchecks.h"
#include "internal/path.h"
#include "internal/process.h"
#include "internal/thread.h"
#include "internal/thread.h"
#include "internal/time.h"


/*******************************************************************************
*   Global Variables                                                           *
*******************************************************************************/
/** The number of calls to RTR3Init. */
static int32_t volatile     g_cUsers = 0;
/** Whether we're currently initializing the IPRT. */
static bool volatile        g_fInitializing = false;

/** The process path.
 * This is used by RTPathExecDir and RTProcGetExecutablePath and set by rtProcInitName. */
DECLHIDDEN(char)            g_szrtProcExePath[RTPATH_MAX];
/** The length of g_szrtProcExePath. */
DECLHIDDEN(size_t)          g_cchrtProcExePath;
/** The length of directory path component of g_szrtProcExePath. */
DECLHIDDEN(size_t)          g_cchrtProcDir;
/** The offset of the process name into g_szrtProcExePath. */
DECLHIDDEN(size_t)          g_offrtProcName;

/**
 * Program start nanosecond TS.
 */
DECLHIDDEN(uint64_t)        g_u64ProgramStartNanoTS;

/**
 * Program start microsecond TS.
 */
DECLHIDDEN(uint64_t)        g_u64ProgramStartMicroTS;

/**
 * Program start millisecond TS.
 */
DECLHIDDEN(uint64_t)        g_u64ProgramStartMilliTS;

/**
 * The process identifier of the running process.
 */
DECLHIDDEN(RTPROCESS)       g_ProcessSelf = NIL_RTPROCESS;

/**
 * The current process priority.
 */
DECLHIDDEN(RTPROCPRIORITY)  g_enmProcessPriority = RTPROCPRIORITY_DEFAULT;

/**
 * Set if the atexit callback has been called, i.e. indicating
 * that the process is terminating.
 */
DECLHIDDEN(bool volatile)   g_frtAtExitCalled = false;

#ifdef IPRT_WITH_ALIGNMENT_CHECKS
/**
 * Whether alignment checks are enabled.
 * This is set if the environment variable IPRT_ALIGNMENT_CHECKS is 1.
 */
RTDATADECL(bool) g_fRTAlignmentChecks = false;
#endif


/**
 * atexit callback.
 *
 * This makes sure any loggers are flushed and will later also work the
 * termination callback chain.
 */
static void rtR3ExitCallback(void)
{
    ASMAtomicWriteBool(&g_frtAtExitCalled, true);

    if (g_cUsers > 0)
    {
        PRTLOGGER pLogger = RTLogGetDefaultInstance();
        if (pLogger)
            RTLogFlush(pLogger);

        pLogger = RTLogRelDefaultInstance();
        if (pLogger)
            RTLogFlush(pLogger);
    }
}


#ifndef RT_OS_WINDOWS
/**
 * Fork callback, child context.
 */
static void rtR3ForkChildCallback(void)
{
    g_ProcessSelf = getpid();
}
#endif /* RT_OS_WINDOWS */

#ifdef RT_OS_OS2
/** Fork completion callback for OS/2.  Only called in the child. */
static void rtR3ForkOs2ChildCompletionCallback(void *pvArg, int rc, __LIBC_FORKCTX enmCtx)
{
    Assert(enmCtx == __LIBC_FORK_CTX_CHILD); NOREF(enmCtx);
    NOREF(pvArg);

    if (!rc)
        rtR3ForkChildCallback();
}

/** Low-level fork callback for OS/2.  */
int rtR3ForkOs2Child(__LIBC_PFORKHANDLE pForkHandle, __LIBC_FORKOP enmOperation)
{
    if (enmOperation == __LIBC_FORK_OP_EXEC_CHILD)
        return pForkHandle->pfnCompletionCallback(pForkHandle, rtR3ForkOs2ChildCompletionCallback, NULL, __LIBC_FORK_CTX_CHILD);
    return 0;
}

_FORK_CHILD1(0, rtR3ForkOs2Child);
#endif /* RT_OS_OS2 */



/**
 * Internal worker which initializes or re-initializes the
 * program path, name and directory globals.
 *
 * @returns IPRT status code.
 * @param   pszProgramPath  The program path, NULL if not specified.
 */
static int rtR3InitProgramPath(const char *pszProgramPath)
{
    /*
     * We're reserving 32 bytes here for file names as what not.
     */
    if (!pszProgramPath)
    {
        int rc = rtProcInitExePath(g_szrtProcExePath, sizeof(g_szrtProcExePath) - 32);
        if (RT_FAILURE(rc))
            return rc;
    }
    else
    {
        size_t cch = strlen(pszProgramPath);
        Assert(cch > 1);
        AssertMsgReturn(cch < sizeof(g_szrtProcExePath) - 32, ("%zu\n", cch), VERR_BUFFER_OVERFLOW);
        memcpy(g_szrtProcExePath, pszProgramPath, cch + 1);
    }

    /*
     * Parse the name.
     */
    ssize_t offName;
    g_cchrtProcExePath = RTPathParse(g_szrtProcExePath, &g_cchrtProcDir, &offName, NULL);
    g_offrtProcName = offName;
    return VINF_SUCCESS;
}


#ifdef IPRT_USE_SIG_CHILD_DUMMY
/**
 * Dummy SIGCHILD handler.
 *
 * Assigned on rtR3Init only when SIGCHILD handler is set SIGIGN or SIGDEF to
 * ensure waitpid works properly for the terminated processes.
 */
static void rtR3SigChildHandler(int iSignal)
{
    NOREF(iSignal);
}
#endif /* IPRT_USE_SIG_CHILD_DUMMY */


/**
 * rtR3Init worker.
 */
static int rtR3InitBody(bool fInitSUPLib, const char *pszProgramPath)
{
    /*
     * Init C runtime locale before we do anything that may end up converting
     * paths or we'll end up using the "C" locale for path conversion.
     */
    setlocale(LC_CTYPE, "");

    /*
     * The Process ID.
     */
#ifdef _MSC_VER
    g_ProcessSelf = _getpid(); /* crappy ansi compiler */
#else
    g_ProcessSelf = getpid();
#endif

#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
# ifdef VBOX
    /*
     * This MUST be done as the very first thing, before any file is opened.
     * The log is opened on demand, but the first log entries may be caused
     * by rtThreadInit() below.
     */
    const char *pszDisableHostCache = getenv("VBOX_DISABLE_HOST_DISK_CACHE");
    if (    pszDisableHostCache != NULL
        &&  *pszDisableHostCache
        &&  strcmp(pszDisableHostCache, "0") != 0)
    {
        RTFileSetForceFlags(RTFILE_O_WRITE, RTFILE_O_WRITE_THROUGH, 0);
        RTFileSetForceFlags(RTFILE_O_READWRITE, RTFILE_O_WRITE_THROUGH, 0);
    }
# endif  /* VBOX */
#endif /* !IN_GUEST && !RT_NO_GIP */

    /*
     * Thread Thread database and adopt the caller thread as 'main'.
     * This must be done before everything else or else we'll call into threading
     * without having initialized TLS entries and suchlike.
     */
    int rc = rtThreadInit();
    AssertMsgRCReturn(rc, ("Failed to initialize threads, rc=%Rrc!\n", rc), rc);

#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
    if (fInitSUPLib)
    {
        /*
         * Init GIP first.
         * (The more time for updates before real use, the better.)
         */
        rc = SUPR3Init(NULL);
        AssertMsgRCReturn(rc, ("Failed to initializable the support library, rc=%Rrc!\n", rc), rc);
    }
#endif

    /*
     * The executable path, name and directory.
     */
    rc = rtR3InitProgramPath(pszProgramPath);
    AssertLogRelMsgRCReturn(rc, ("Failed to get executable directory path, rc=%Rrc!\n", rc), rc);

#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
    /*
     * The threading is initialized we can safely sleep a bit if GIP
     * needs some time to update itself updating.
     */
    if (fInitSUPLib && g_pSUPGlobalInfoPage)
    {
        RTThreadSleep(20);
        RTTimeNanoTS();
    }
#endif

    /*
     * Init the program start TSes.
     * Do that here to be sure that the GIP time was properly updated the 1st time.
     */
    g_u64ProgramStartNanoTS = RTTimeNanoTS();
    g_u64ProgramStartMicroTS = g_u64ProgramStartNanoTS / 1000;
    g_u64ProgramStartMilliTS = g_u64ProgramStartNanoTS / 1000000;

    /*
     * The remainder cannot easily be undone, so it has to go last.
     */

    /* Fork and exit callbacks. */
#if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2)
    rc = pthread_atfork(NULL, NULL, rtR3ForkChildCallback);
    AssertMsg(rc == 0, ("%d\n", rc));
#endif
    atexit(rtR3ExitCallback);

#ifdef IPRT_USE_SIG_CHILD_DUMMY
    /*
     * SIGCHLD must not be ignored (that's default), otherwise posix compliant waitpid
     * implementations won't work right.
     */
    for (;;)
    {
        struct sigaction saOld;
        rc = sigaction(SIGCHLD, 0, &saOld);         AssertMsg(rc == 0, ("%d/%d\n", rc, errno));
        if (    rc != 0
            ||  (saOld.sa_flags & SA_SIGINFO)
            || (   saOld.sa_handler != SIG_IGN
                && saOld.sa_handler != SIG_DFL)
           )
            break;

        /* Try install dummy handler. */
        struct sigaction saNew = saOld;
        saNew.sa_flags   = SA_NOCLDSTOP | SA_RESTART;
        saNew.sa_handler = rtR3SigChildHandler;
        rc = sigemptyset(&saNew.sa_mask);           AssertMsg(rc == 0, ("%d/%d\n", rc, errno));
        struct sigaction saOld2;
        rc = sigaction(SIGCHLD, &saNew, &saOld2);   AssertMsg(rc == 0, ("%d/%d\n", rc, errno));
        if (    rc != 0
            ||  (   saOld2.sa_handler == saOld.sa_handler
                 && !(saOld2.sa_flags & SA_SIGINFO))
           )
            break;

        /* Race during dynamic load, restore and try again... */
        sigaction(SIGCHLD, &saOld2, NULL);
        RTThreadYield();
    }
#endif /* IPRT_USE_SIG_CHILD_DUMMY */

#ifdef IPRT_WITH_ALIGNMENT_CHECKS
    /*
     * Enable alignment checks.
     */
    const char *pszAlignmentChecks = getenv("IPRT_ALIGNMENT_CHECKS");
    g_fRTAlignmentChecks = pszAlignmentChecks != NULL
                        && pszAlignmentChecks[0] == '1'
                        && pszAlignmentChecks[1] == '\0';
    if (g_fRTAlignmentChecks)
        IPRT_ALIGNMENT_CHECKS_ENABLE();
#endif

    return VINF_SUCCESS;
}


/**
 * Internal initialization worker.
 *
 * @returns IPRT status code.
 * @param   fInitSUPLib     Whether to call SUPR3Init.
 * @param   pszProgramPath  The program path, NULL if not specified.
 */
static int rtR3Init(bool fInitSUPLib, const char *pszProgramPath)
{
    /* no entry log flow, because prefixes and thread may freak out. */

    /*
     * Do reference counting, only initialize the first time around.
     *
     * We are ASSUMING that nobody will be able to race RTR3Init calls when the
     * first one, the real init, is running (second assertion).
     */
    int32_t cUsers = ASMAtomicIncS32(&g_cUsers);
    if (cUsers != 1)
    {
        AssertMsg(cUsers > 1, ("%d\n", cUsers));
        Assert(!g_fInitializing);
#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
        if (fInitSUPLib)
            SUPR3Init(NULL);
#endif
        if (!pszProgramPath)
            return VINF_SUCCESS;
        return rtR3InitProgramPath(pszProgramPath);
    }
    ASMAtomicWriteBool(&g_fInitializing, true);

    /*
     * Do the initialization.
     */
    int rc = rtR3InitBody(fInitSUPLib, pszProgramPath);
    if (RT_FAILURE(rc))
    {
        /* failure */
        ASMAtomicWriteBool(&g_fInitializing, false);
        ASMAtomicDecS32(&g_cUsers);
        return rc;
    }

    /* success */
    LogFlow(("RTR3Init: returns VINF_SUCCESS\n"));
    ASMAtomicWriteBool(&g_fInitializing, false);
    return VINF_SUCCESS;
}


RTR3DECL(int) RTR3Init(void)
{
    return rtR3Init(false /* fInitSUPLib */, NULL);
}


RTR3DECL(int) RTR3InitEx(uint32_t iVersion, const char *pszProgramPath, bool fInitSUPLib)
{
    AssertReturn(iVersion == 0, VERR_NOT_SUPPORTED);
    return rtR3Init(fInitSUPLib, pszProgramPath);
}


RTR3DECL(int) RTR3InitWithProgramPath(const char *pszProgramPath)
{
    return rtR3Init(false /* fInitSUPLib */, pszProgramPath);
}


RTR3DECL(int) RTR3InitAndSUPLib(void)
{
    return rtR3Init(true /* fInitSUPLib */, NULL /* pszProgramPath */);
}


RTR3DECL(int) RTR3InitAndSUPLibWithProgramPath(const char *pszProgramPath)
{
    return rtR3Init(true /* fInitSUPLib */, pszProgramPath);
}


#if 0 /** @todo implement RTR3Term. */
RTR3DECL(void) RTR3Term(void)
{
}
#endif

