fixed IO redirection to work in wxExecute() in console applications (including the...

[wxWidgets.git] / src / unix / utilsunx.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        src/unix/utilsunx.cpp
// Purpose:     generic Unix implementation of many wx functions
// Author:      Vadim Zeitlin
// Id:          $Id$
// Copyright:   (c) 1998 Robert Roebling, Vadim Zeitlin
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// ============================================================================
// declarations
// ============================================================================

// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------

// for compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#include "wx/utils.h"

#define USE_PUTENV (!defined(HAVE_SETENV) && defined(HAVE_PUTENV))

#ifndef WX_PRECOMP
    #include "wx/string.h"
    #include "wx/intl.h"
    #include "wx/log.h"
    #include "wx/app.h"
    #include "wx/wxcrtvararg.h"
    #if USE_PUTENV
        #include "wx/module.h"
        #include "wx/hashmap.h"
    #endif
#endif

#include "wx/apptrait.h"

#include "wx/process.h"
#include "wx/thread.h"

#include "wx/wfstream.h"

#include "wx/private/selectdispatcher.h"
#include "wx/private/fdiodispatcher.h"
#include "wx/unix/execute.h"
#include "wx/unix/private.h"

#ifdef wxHAS_GENERIC_PROCESS_CALLBACK
#include "wx/private/fdiodispatcher.h"
#endif

#include <pwd.h>
#include <sys/wait.h>       // waitpid()

#ifdef HAVE_SYS_SELECT_H
#   include <sys/select.h>
#endif

#define HAS_PIPE_INPUT_STREAM (wxUSE_STREAMS && wxUSE_FILE)

#if HAS_PIPE_INPUT_STREAM

// define this to let wxexec.cpp know that we know what we're doing
#define _WX_USED_BY_WXEXECUTE_
#include "../common/execcmn.cpp"

#endif // HAS_PIPE_INPUT_STREAM

#if defined(__MWERKS__) && defined(__MACH__)
    #ifndef WXWIN_OS_DESCRIPTION
        #define WXWIN_OS_DESCRIPTION "MacOS X"
    #endif
    #ifndef HAVE_NANOSLEEP
        #define HAVE_NANOSLEEP
    #endif
    #ifndef HAVE_UNAME
        #define HAVE_UNAME
    #endif

    // our configure test believes we can use sigaction() if the function is
    // available but Metrowekrs with MSL run-time does have the function but
    // doesn't have sigaction struct so finally we can't use it...
    #ifdef __MSL__
        #undef wxUSE_ON_FATAL_EXCEPTION
        #define wxUSE_ON_FATAL_EXCEPTION 0
    #endif
#endif

// not only the statfs syscall is called differently depending on platform, but
// one of its incarnations, statvfs(), takes different arguments under
// different platforms and even different versions of the same system (Solaris
// 7 and 8): if you want to test for this, don't forget that the problems only
// appear if the large files support is enabled
#ifdef HAVE_STATFS
    #ifdef __BSD__
        #include <sys/param.h>
        #include <sys/mount.h>
    #else // !__BSD__
        #include <sys/vfs.h>
    #endif // __BSD__/!__BSD__

    #define wxStatfs statfs

    #ifndef HAVE_STATFS_DECL
        // some systems lack statfs() prototype in the system headers (AIX 4)
        extern "C" int statfs(const char *path, struct statfs *buf);
    #endif
#endif // HAVE_STATFS

#ifdef HAVE_STATVFS
    #include <sys/statvfs.h>

    #define wxStatfs statvfs
#endif // HAVE_STATVFS

#if defined(HAVE_STATFS) || defined(HAVE_STATVFS)
    // WX_STATFS_T is detected by configure
    #define wxStatfs_t WX_STATFS_T
#endif

// SGI signal.h defines signal handler arguments differently depending on
// whether _LANGUAGE_C_PLUS_PLUS is set or not - do set it
#if defined(__SGI__) && !defined(_LANGUAGE_C_PLUS_PLUS)
    #define _LANGUAGE_C_PLUS_PLUS 1
#endif // SGI hack

#include <stdarg.h>
#include <dirent.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <netdb.h>
#include <signal.h>
#include <fcntl.h>          // for O_WRONLY and friends
#include <time.h>           // nanosleep() and/or usleep()
#include <ctype.h>          // isspace()
#include <sys/time.h>       // needed for FD_SETSIZE

#ifdef HAVE_UNAME
    #include <sys/utsname.h> // for uname()
#endif // HAVE_UNAME

// Used by wxGetFreeMemory().
#ifdef __SGI__
    #include <sys/sysmp.h>
    #include <sys/sysinfo.h>   // for SAGET and MINFO structures
#endif

// ----------------------------------------------------------------------------
// conditional compilation
// ----------------------------------------------------------------------------

// many versions of Unices have this function, but it is not defined in system
// headers - please add your system here if it is the case for your OS.
// SunOS < 5.6 (i.e. Solaris < 2.6) and DG-UX are like this.
#if !defined(HAVE_USLEEP) && \
    ((defined(__SUN__) && !defined(__SunOs_5_6) && \
                         !defined(__SunOs_5_7) && !defined(__SUNPRO_CC)) || \
     defined(__osf__) || defined(__EMX__))
    extern "C"
    {
        #ifdef __EMX__
            /* I copied this from the XFree86 diffs. AV. */
            #define INCL_DOSPROCESS
            #include <os2.h>
            inline void usleep(unsigned long delay)
            {
                DosSleep(delay ? (delay/1000l) : 1l);
            }
        #else // Unix
            int usleep(unsigned int usec);
        #endif // __EMX__/Unix
    };

    #define HAVE_USLEEP 1
#endif // Unices without usleep()

// ============================================================================
// implementation
// ============================================================================

// ----------------------------------------------------------------------------
// sleeping
// ----------------------------------------------------------------------------

void wxSleep(int nSecs)
{
    sleep(nSecs);
}

void wxMicroSleep(unsigned long microseconds)
{
#if defined(HAVE_NANOSLEEP)
    timespec tmReq;
    tmReq.tv_sec = (time_t)(microseconds / 1000000);
    tmReq.tv_nsec = (microseconds % 1000000) * 1000;

    // we're not interested in remaining time nor in return value
    (void)nanosleep(&tmReq, (timespec *)NULL);
#elif defined(HAVE_USLEEP)
    // uncomment this if you feel brave or if you are sure that your version
    // of Solaris has a safe usleep() function but please notice that usleep()
    // is known to lead to crashes in MT programs in Solaris 2.[67] and is not
    // documented as MT-Safe
    #if defined(__SUN__) && wxUSE_THREADS
        #error "usleep() cannot be used in MT programs under Solaris."
    #endif // Sun

    usleep(microseconds);
#elif defined(HAVE_SLEEP)
    // under BeOS sleep() takes seconds (what about other platforms, if any?)
    sleep(microseconds * 1000000);
#else // !sleep function
    #error "usleep() or nanosleep() function required for wxMicroSleep"
#endif // sleep function
}

void wxMilliSleep(unsigned long milliseconds)
{
    wxMicroSleep(milliseconds*1000);
}

// ----------------------------------------------------------------------------
// process management
// ----------------------------------------------------------------------------

int wxKill(long pid, wxSignal sig, wxKillError *rc, int flags)
{
    int err = kill((pid_t) (flags & wxKILL_CHILDREN) ? -pid : pid, (int)sig);
    if ( rc )
    {
        switch ( err ? errno : 0 )
        {
            case 0:
                *rc = wxKILL_OK;
                break;

            case EINVAL:
                *rc = wxKILL_BAD_SIGNAL;
                break;

            case EPERM:
                *rc = wxKILL_ACCESS_DENIED;
                break;

            case ESRCH:
                *rc = wxKILL_NO_PROCESS;
                break;

            default:
                // this goes against Unix98 docs so log it
                wxLogDebug(_T("unexpected kill(2) return value %d"), err);

                // something else...
                *rc = wxKILL_ERROR;
        }
    }

    return err;
}

#define WXEXECUTE_NARGS   127

#if defined(__DARWIN__)
long wxMacExecute(wxChar **argv,
               int flags,
               wxProcess *process);
#endif

long wxExecute( const wxString& command, int flags, wxProcess *process )
{
    wxCHECK_MSG( !command.empty(), 0, wxT("can't exec empty command") );

    wxLogTrace(wxT("exec"), wxT("Executing \"%s\""), command.c_str());

#if wxUSE_THREADS
    // fork() doesn't mix well with POSIX threads: on many systems the program
    // deadlocks or crashes for some reason. Probably our code is buggy and
    // doesn't do something which must be done to allow this to work, but I
    // don't know what yet, so for now just warn the user (this is the least we
    // can do) about it
    wxASSERT_MSG( wxThread::IsMain(),
                    _T("wxExecute() can be called only from the main thread") );
#endif // wxUSE_THREADS

    int argc = 0;
    wxChar *argv[WXEXECUTE_NARGS];
    wxString argument;
    const wxChar *cptr = command.c_str();
    wxChar quotechar = wxT('\0'); // is arg quoted?
    bool escaped = false;

    // split the command line in arguments
    do
    {
        argument = wxEmptyString;
        quotechar = wxT('\0');

        // eat leading whitespace:
        while ( wxIsspace(*cptr) )
            cptr++;

        if ( *cptr == wxT('\'') || *cptr == wxT('"') )
            quotechar = *cptr++;

        do
        {
            if ( *cptr == wxT('\\') && ! escaped )
            {
                escaped = true;
                cptr++;
                continue;
            }

            // all other characters:
            argument += *cptr++;
            escaped = false;

            // have we reached the end of the argument?
            if ( (*cptr == quotechar && ! escaped)
                 || (quotechar == wxT('\0') && wxIsspace(*cptr))
                 || *cptr == wxT('\0') )
            {
                wxASSERT_MSG( argc < WXEXECUTE_NARGS,
                              wxT("too many arguments in wxExecute") );

                argv[argc] = new wxChar[argument.length() + 1];
                wxStrcpy(argv[argc], argument.c_str());
                argc++;

                // if not at end of buffer, swallow last character:
                if(*cptr)
                    cptr++;

                break; // done with this one, start over
            }
        } while(*cptr);
    } while(*cptr);
    argv[argc] = NULL;

    long lRc;
#if defined(__DARWIN__)
    // wxMacExecute only executes app bundles.
    // It returns an error code if the target is not an app bundle, thus falling
    // through to the regular wxExecute for non app bundles.
    lRc = wxMacExecute(argv, flags, process);
    if( lRc != ((flags & wxEXEC_SYNC) ? -1 : 0))
        return lRc;
#endif

    // do execute the command
    lRc = wxExecute(argv, flags, process);

    // clean up
    argc = 0;
    while( argv[argc] )
        delete [] argv[argc++];

    return lRc;
}

// ----------------------------------------------------------------------------
// wxShell
// ----------------------------------------------------------------------------

static wxString wxMakeShellCommand(const wxString& command)
{
    wxString cmd;
    if ( !command )
    {
        // just an interactive shell
        cmd = _T("xterm");
    }
    else
    {
        // execute command in a shell
        cmd << _T("/bin/sh -c '") << command << _T('\'');
    }

    return cmd;
}

bool wxShell(const wxString& command)
{
    return wxExecute(wxMakeShellCommand(command), wxEXEC_SYNC) == 0;
}

bool wxShell(const wxString& command, wxArrayString& output)
{
    wxCHECK_MSG( !command.empty(), false, _T("can't exec shell non interactively") );

    return wxExecute(wxMakeShellCommand(command), output);
}

// Shutdown or reboot the PC
bool wxShutdown(wxShutdownFlags wFlags)
{
    wxChar level;
    switch ( wFlags )
    {
        case wxSHUTDOWN_POWEROFF:
            level = _T('0');
            break;

        case wxSHUTDOWN_REBOOT:
            level = _T('6');
            break;

        default:
            wxFAIL_MSG( _T("unknown wxShutdown() flag") );
            return false;
    }

    return system(wxString::Format(_T("init %c"), level).mb_str()) == 0;
}

// ----------------------------------------------------------------------------
// wxStream classes to support IO redirection in wxExecute
// ----------------------------------------------------------------------------

#if HAS_PIPE_INPUT_STREAM

bool wxPipeInputStream::CanRead() const
{
    if ( m_lasterror == wxSTREAM_EOF )
        return false;

    // check if there is any input available
    struct timeval tv;
    tv.tv_sec = 0;
    tv.tv_usec = 0;

    const int fd = m_file->fd();

    fd_set readfds;

    wxFD_ZERO(&readfds);
    wxFD_SET(fd, &readfds);

    switch ( select(fd + 1, &readfds, NULL, NULL, &tv) )
    {
        case -1:
            wxLogSysError(_("Impossible to get child process input"));
            // fall through

        case 0:
            return false;

        default:
            wxFAIL_MSG(_T("unexpected select() return value"));
            // still fall through

        case 1:
            // input available -- or maybe not, as select() returns 1 when a
            // read() will complete without delay, but it could still not read
            // anything
            return !Eof();
    }
}

#endif // HAS_PIPE_INPUT_STREAM

// ----------------------------------------------------------------------------
// wxExecute: the real worker function
// ----------------------------------------------------------------------------

long wxExecute(wxChar **argv, int flags, wxProcess *process)
{
    // for the sync execution, we return -1 to indicate failure, but for async
    // case we return 0 which is never a valid PID
    //
    // we define this as a macro, not a variable, to avoid compiler warnings
    // about "ERROR_RETURN_CODE value may be clobbered by fork()"
    #define ERROR_RETURN_CODE ((flags & wxEXEC_SYNC) ? -1 : 0)

    wxCHECK_MSG( *argv, ERROR_RETURN_CODE, wxT("can't exec empty command") );

#if wxUSE_UNICODE
    int mb_argc = 0;
    char *mb_argv[WXEXECUTE_NARGS];

    while (argv[mb_argc])
    {
        wxWX2MBbuf mb_arg = wxSafeConvertWX2MB(argv[mb_argc]);
        mb_argv[mb_argc] = strdup(mb_arg);
        mb_argc++;
    }
    mb_argv[mb_argc] = (char *) NULL;

    // this macro will free memory we used above
    #define ARGS_CLEANUP                                 \
        for ( mb_argc = 0; mb_argv[mb_argc]; mb_argc++ ) \
            free(mb_argv[mb_argc])
#else // ANSI
    // no need for cleanup
    #define ARGS_CLEANUP

    wxChar **mb_argv = argv;
#endif // Unicode/ANSI

    // we want this function to work even if there is no wxApp so ensure that
    // we have a valid traits pointer
    wxConsoleAppTraits traitsConsole;
    wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits() : NULL;
    if ( !traits )
        traits = &traitsConsole;

    // this struct contains all information which we pass to and from
    // wxAppTraits methods
    wxExecuteData execData;
    execData.flags = flags;
    execData.process = process;

    // create pipes
    if ( !traits->CreateEndProcessPipe(execData) )
    {
        wxLogError( _("Failed to execute '%s'\n"), *argv );

        ARGS_CLEANUP;

        return ERROR_RETURN_CODE;
    }

    // pipes for inter process communication
    wxPipe pipeIn,      // stdin
           pipeOut,     // stdout
           pipeErr;     // stderr

    if ( process && process->IsRedirected() )
    {
        if ( !pipeIn.Create() || !pipeOut.Create() || !pipeErr.Create() )
        {
            wxLogError( _("Failed to execute '%s'\n"), *argv );

            ARGS_CLEANUP;

            return ERROR_RETURN_CODE;
        }
    }

    // fork the process
    //
    // NB: do *not* use vfork() here, it completely breaks this code for some
    //     reason under Solaris (and maybe others, although not under Linux)
    //     But on OpenVMS we do not have fork so we have to use vfork and
    //     cross our fingers that it works.
#ifdef __VMS
   pid_t pid = vfork();
#else
   pid_t pid = fork();
#endif
   if ( pid == -1 )     // error?
    {
        wxLogSysError( _("Fork failed") );

        ARGS_CLEANUP;

        return ERROR_RETURN_CODE;
    }
    else if ( pid == 0 )  // we're in child
    {
        // These lines close the open file descriptors to to avoid any
        // input/output which might block the process or irritate the user. If
        // one wants proper IO for the subprocess, the right thing to do is to
        // start an xterm executing it.
        if ( !(flags & wxEXEC_SYNC) )
        {
            // FD_SETSIZE is unsigned under BSD, signed under other platforms
            // so we need a cast to avoid warnings on all platforms
            for ( int fd = 0; fd < (int)FD_SETSIZE; fd++ )
            {
                if ( fd == pipeIn[wxPipe::Read]
                        || fd == pipeOut[wxPipe::Write]
                        || fd == pipeErr[wxPipe::Write]
                        || traits->IsWriteFDOfEndProcessPipe(execData, fd) )
                {
                    // don't close this one, we still need it
                    continue;
                }

                // leave stderr opened too, it won't do any harm
                if ( fd != STDERR_FILENO )
                    close(fd);
            }
        }

#if !defined(__VMS) && !defined(__EMX__)
        if ( flags & wxEXEC_MAKE_GROUP_LEADER )
        {
            // Set process group to child process' pid.  Then killing -pid
            // of the parent will kill the process and all of its children.
            setsid();
        }
#endif // !__VMS

        // reading side can be safely closed but we should keep the write one
        // opened
        traits->DetachWriteFDOfEndProcessPipe(execData);

        // redirect stdin, stdout and stderr
        if ( pipeIn.IsOk() )
        {
            if ( dup2(pipeIn[wxPipe::Read], STDIN_FILENO) == -1 ||
                 dup2(pipeOut[wxPipe::Write], STDOUT_FILENO) == -1 ||
                 dup2(pipeErr[wxPipe::Write], STDERR_FILENO) == -1 )
            {
                wxLogSysError(_("Failed to redirect child process input/output"));
            }

            pipeIn.Close();
            pipeOut.Close();
            pipeErr.Close();
        }

        execvp (*mb_argv, mb_argv);

        fprintf(stderr, "execvp(");
        // CS changed ppc to ppc_ as ppc is not available under mac os CW Mach-O
        for ( char **ppc_ = mb_argv; *ppc_; ppc_++ )
            fprintf(stderr, "%s%s", ppc_ == mb_argv ? "" : ", ", *ppc_);
        fprintf(stderr, ") failed with error %d!\n", errno);

        // there is no return after successful exec()
        _exit(-1);

        // some compilers complain about missing return - of course, they
        // should know that exit() doesn't return but what else can we do if
        // they don't?
        //
        // and, sure enough, other compilers complain about unreachable code
        // after exit() call, so we can just always have return here...
#if defined(__VMS) || defined(__INTEL_COMPILER)
        return 0;
#endif
    }
    else // we're in parent
    {
        ARGS_CLEANUP;

        // save it for WaitForChild() use
        execData.pid = pid;

        // prepare for IO redirection

#if HAS_PIPE_INPUT_STREAM
        // the input buffer bufOut is connected to stdout, this is why it is
        // called bufOut and not bufIn
        wxStreamTempInputBuffer bufOut,
                                bufErr;

        if ( process && process->IsRedirected() )
        {
            wxOutputStream *inStream =
                new wxFileOutputStream(pipeIn.Detach(wxPipe::Write));

            const int fdOut = pipeOut.Detach(wxPipe::Read);
            wxPipeInputStream *outStream = new wxPipeInputStream(fdOut);

            const int fdErr = pipeErr.Detach(wxPipe::Read);
            wxPipeInputStream *errStream = new wxPipeInputStream(fdErr);

            process->SetPipeStreams(outStream, inStream, errStream);

            bufOut.Init(outStream);
            bufErr.Init(errStream);

            execData.bufOut = &bufOut;
            execData.bufErr = &bufErr;

            execData.fdOut = fdOut;
            execData.fdErr = fdErr;
        }
#endif // HAS_PIPE_INPUT_STREAM

        if ( pipeIn.IsOk() )
        {
            pipeIn.Close();
            pipeOut.Close();
            pipeErr.Close();
        }

        return traits->WaitForChild(execData);
    }

#if !defined(__VMS) && !defined(__INTEL_COMPILER)
    return ERROR_RETURN_CODE;
#endif
}

#undef ERROR_RETURN_CODE
#undef ARGS_CLEANUP

// ----------------------------------------------------------------------------
// file and directory functions
// ----------------------------------------------------------------------------

const wxChar* wxGetHomeDir( wxString *home  )
{
    *home = wxGetUserHome();
    wxString tmp;
    if ( home->empty() )
        *home = wxT("/");
#ifdef __VMS
    tmp = *home;
    if ( tmp.Last() != wxT(']'))
        if ( tmp.Last() != wxT('/')) *home << wxT('/');
#endif
    return home->c_str();
}

wxString wxGetUserHome( const wxString &user )
{
    struct passwd *who = (struct passwd *) NULL;

    if ( !user )
    {
        wxChar *ptr;

        if ((ptr = wxGetenv(wxT("HOME"))) != NULL)
        {
            return ptr;
        }

        if ((ptr = wxGetenv(wxT("USER"))) != NULL ||
             (ptr = wxGetenv(wxT("LOGNAME"))) != NULL)
        {
            who = getpwnam(wxSafeConvertWX2MB(ptr));
        }

        // make sure the user exists!
        if ( !who )
        {
            who = getpwuid(getuid());
        }
    }
    else
    {
      who = getpwnam (user.mb_str());
    }

    return wxSafeConvertMB2WX(who ? who->pw_dir : 0);
}

// ----------------------------------------------------------------------------
// network and user id routines
// ----------------------------------------------------------------------------

// private utility function which returns output of the given command, removing
// the trailing newline
static wxString wxGetCommandOutput(const wxString &cmd)
{
    FILE *f = popen(cmd.ToAscii(), "r");
    if ( !f )
    {
        wxLogSysError(_T("Executing \"%s\" failed"), cmd.c_str());
        return wxEmptyString;
    }

    wxString s;
    char buf[256];
    while ( !feof(f) )
    {
        if ( !fgets(buf, sizeof(buf), f) )
            break;

        s += wxString::FromAscii(buf);
    }

    pclose(f);

    if ( !s.empty() && s.Last() == _T('\n') )
        s.RemoveLast();

    return s;
}

// retrieve either the hostname or FQDN depending on platform (caller must
// check whether it's one or the other, this is why this function is for
// private use only)
static bool wxGetHostNameInternal(wxChar *buf, int sz)
{
    wxCHECK_MSG( buf, false, wxT("NULL pointer in wxGetHostNameInternal") );

    *buf = wxT('\0');

    // we're using uname() which is POSIX instead of less standard sysinfo()
#if defined(HAVE_UNAME)
    struct utsname uts;
    bool ok = uname(&uts) != -1;
    if ( ok )
    {
        wxStrncpy(buf, wxSafeConvertMB2WX(uts.nodename), sz - 1);
        buf[sz] = wxT('\0');
    }
#elif defined(HAVE_GETHOSTNAME)
    char cbuf[sz];
    bool ok = gethostname(cbuf, sz) != -1;
    if ( ok )
    {
        wxStrncpy(buf, wxSafeConvertMB2WX(cbuf), sz - 1);
        buf[sz] = wxT('\0');
    }
#else // no uname, no gethostname
    wxFAIL_MSG(wxT("don't know host name for this machine"));

    bool ok = false;
#endif // uname/gethostname

    if ( !ok )
    {
        wxLogSysError(_("Cannot get the hostname"));
    }

    return ok;
}

bool wxGetHostName(wxChar *buf, int sz)
{
    bool ok = wxGetHostNameInternal(buf, sz);

    if ( ok )
    {
        // BSD systems return the FQDN, we only want the hostname, so extract
        // it (we consider that dots are domain separators)
        wxChar *dot = wxStrchr(buf, wxT('.'));
        if ( dot )
        {
            // nuke it
            *dot = wxT('\0');
        }
    }

    return ok;
}

bool wxGetFullHostName(wxChar *buf, int sz)
{
    bool ok = wxGetHostNameInternal(buf, sz);

    if ( ok )
    {
        if ( !wxStrchr(buf, wxT('.')) )
        {
            struct hostent *host = gethostbyname(wxSafeConvertWX2MB(buf));
            if ( !host )
            {
                wxLogSysError(_("Cannot get the official hostname"));

                ok = false;
            }
            else
            {
                // the canonical name
                wxStrncpy(buf, wxSafeConvertMB2WX(host->h_name), sz);
            }
        }
        //else: it's already a FQDN (BSD behaves this way)
    }

    return ok;
}

bool wxGetUserId(wxChar *buf, int sz)
{
    struct passwd *who;

    *buf = wxT('\0');
    if ((who = getpwuid(getuid ())) != NULL)
    {
        wxStrncpy (buf, wxSafeConvertMB2WX(who->pw_name), sz - 1);
        return true;
    }

    return false;
}

bool wxGetUserName(wxChar *buf, int sz)
{
#ifdef HAVE_PW_GECOS
    struct passwd *who;

    *buf = wxT('\0');
    if ((who = getpwuid (getuid ())) != NULL)
    {
       char *comma = strchr(who->pw_gecos, ',');
       if (comma)
           *comma = '\0'; // cut off non-name comment fields
       wxStrncpy (buf, wxSafeConvertMB2WX(who->pw_gecos), sz - 1);
       return true;
    }

    return false;
#else // !HAVE_PW_GECOS
    return wxGetUserId(buf, sz);
#endif // HAVE_PW_GECOS/!HAVE_PW_GECOS
}

bool wxIsPlatform64Bit()
{
    const wxString machine = wxGetCommandOutput(wxT("uname -m"));

    // the test for "64" is obviously not 100% reliable but seems to work fine
    // in practice
    return machine.Contains(wxT("64")) ||
                machine.Contains(wxT("alpha"));
}

// these functions are in mac/utils.cpp for wxMac
#ifndef __WXMAC__

wxOperatingSystemId wxGetOsVersion(int *verMaj, int *verMin)
{
    // get OS version
    int major, minor;
    wxString release = wxGetCommandOutput(wxT("uname -r"));
    if ( release.empty() ||
         wxSscanf(release.c_str(), wxT("%d.%d"), &major, &minor) != 2 )
    {
        // failed to get version string or unrecognized format
        major =
        minor = -1;
    }

    if ( verMaj )
        *verMaj = major;
    if ( verMin )
        *verMin = minor;

    // try to understand which OS are we running
    wxString kernel = wxGetCommandOutput(wxT("uname -s"));
    if ( kernel.empty() )
        kernel = wxGetCommandOutput(wxT("uname -o"));

    if ( kernel.empty() )
        return wxOS_UNKNOWN;

    return wxPlatformInfo::GetOperatingSystemId(kernel);
}

wxString wxGetOsDescription()
{
    return wxGetCommandOutput(wxT("uname -s -r -m"));
}

#endif // !__WXMAC__

unsigned long wxGetProcessId()
{
    return (unsigned long)getpid();
}

wxMemorySize wxGetFreeMemory()
{
#if defined(__LINUX__)
    // get it from /proc/meminfo
    FILE *fp = fopen("/proc/meminfo", "r");
    if ( fp )
    {
        long memFree = -1;

        char buf[1024];
        if ( fgets(buf, WXSIZEOF(buf), fp) && fgets(buf, WXSIZEOF(buf), fp) )
        {
            // /proc/meminfo changed its format in kernel 2.6
            if ( wxPlatformInfo().CheckOSVersion(2, 6) )
            {
                unsigned long cached, buffers;
                sscanf(buf, "MemFree: %ld", &memFree);

                fgets(buf, WXSIZEOF(buf), fp);
                sscanf(buf, "Buffers: %lu", &buffers);

                fgets(buf, WXSIZEOF(buf), fp);
                sscanf(buf, "Cached: %lu", &cached);

                // add to "MemFree" also the "Buffers" and "Cached" values as
                // free(1) does as otherwise the value never makes sense: for
                // kernel 2.6 it's always almost 0
                memFree += buffers + cached;

                // values here are always expressed in kB and we want bytes
                memFree *= 1024;
            }
            else // Linux 2.4 (or < 2.6, anyhow)
            {
                long memTotal, memUsed;
                sscanf(buf, "Mem: %ld %ld %ld", &memTotal, &memUsed, &memFree);
            }
        }

        fclose(fp);

        return (wxMemorySize)memFree;
    }
#elif defined(__SGI__)
    struct rminfo realmem;
    if ( sysmp(MP_SAGET, MPSA_RMINFO, &realmem, sizeof realmem) == 0 )
        return ((wxMemorySize)realmem.physmem * sysconf(_SC_PAGESIZE));
#elif defined(_SC_AVPHYS_PAGES)
    return ((wxMemorySize)sysconf(_SC_AVPHYS_PAGES))*sysconf(_SC_PAGESIZE);
//#elif defined(__FREEBSD__) -- might use sysctl() to find it out, probably
#endif

    // can't find it out
    return -1;
}

bool wxGetDiskSpace(const wxString& path, wxDiskspaceSize_t *pTotal, wxDiskspaceSize_t *pFree)
{
#if defined(HAVE_STATFS) || defined(HAVE_STATVFS)
    // the case to "char *" is needed for AIX 4.3
    wxStatfs_t fs;
    if ( wxStatfs((char *)(const char*)path.fn_str(), &fs) != 0 )
    {
        wxLogSysError( wxT("Failed to get file system statistics") );

        return false;
    }

    // under Solaris we also have to use f_frsize field instead of f_bsize
    // which is in general a multiple of f_frsize
#ifdef HAVE_STATVFS
    wxDiskspaceSize_t blockSize = fs.f_frsize;
#else // HAVE_STATFS
    wxDiskspaceSize_t blockSize = fs.f_bsize;
#endif // HAVE_STATVFS/HAVE_STATFS

    if ( pTotal )
    {
        *pTotal = wxDiskspaceSize_t(fs.f_blocks) * blockSize;
    }

    if ( pFree )
    {
        *pFree = wxDiskspaceSize_t(fs.f_bavail) * blockSize;
    }

    return true;
#else // !HAVE_STATFS && !HAVE_STATVFS
    return false;
#endif // HAVE_STATFS
}

// ----------------------------------------------------------------------------
// env vars
// ----------------------------------------------------------------------------

#if USE_PUTENV

WX_DECLARE_STRING_HASH_MAP(char *, wxEnvVars);

static wxEnvVars gs_envVars;

class wxSetEnvModule : public wxModule
{
public:
    virtual bool OnInit() { return true; }
    virtual void OnExit()
    {
        for ( wxEnvVars::const_iterator i = gs_envVars.begin();
              i != gs_envVars.end();
              ++i )
        {
            free(i->second);
        }

        gs_envVars.clear();
    }

    DECLARE_DYNAMIC_CLASS(wxSetEnvModule)
};

IMPLEMENT_DYNAMIC_CLASS(wxSetEnvModule, wxModule)

#endif // USE_PUTENV

bool wxGetEnv(const wxString& var, wxString *value)
{
    // wxGetenv is defined as getenv()
    char *p = wxGetenv(var);
    if ( !p )
        return false;

    if ( value )
    {
        *value = p;
    }

    return true;
}

static bool wxDoSetEnv(const wxString& variable, const char *value)
{
#if defined(HAVE_SETENV)
    if ( !value )
    {
#ifdef HAVE_UNSETENV
        // don't test unsetenv() return value: it's void on some systems (at
        // least Darwin)
        unsetenv(variable.mb_str());
        return true;
#else
        value = ""; // we can't pass NULL to setenv()
#endif
    }

    return setenv(variable.mb_str(), value, 1 /* overwrite */) == 0;
#elif defined(HAVE_PUTENV)
    wxString s = variable;
    if ( value )
        s << _T('=') << value;

    // transform to ANSI
    const wxWX2MBbuf p = s.mb_str();

    char *buf = (char *)malloc(strlen(p) + 1);
    strcpy(buf, p);

    // store the string to free() it later
    wxEnvVars::iterator i = gs_envVars.find(variable);
    if ( i != gs_envVars.end() )
    {
        free(i->second);
        i->second = buf;
    }
    else // this variable hadn't been set before
    {
        gs_envVars[variable] = buf;
    }

    return putenv(buf) == 0;
#else // no way to set an env var
    return false;
#endif
}

bool wxSetEnv(const wxString& variable, const wxString& value)
{
    return wxDoSetEnv(variable, value.mb_str());
}

bool wxUnsetEnv(const wxString& variable)
{
    return wxDoSetEnv(variable, NULL);
}

// ----------------------------------------------------------------------------
// signal handling
// ----------------------------------------------------------------------------

#if wxUSE_ON_FATAL_EXCEPTION

#include <signal.h>

extern "C" void wxFatalSignalHandler(wxTYPE_SA_HANDLER)
{
    if ( wxTheApp )
    {
        // give the user a chance to do something special about this
        wxTheApp->OnFatalException();
    }

    abort();
}

bool wxHandleFatalExceptions(bool doit)
{
    // old sig handlers
    static bool s_savedHandlers = false;
    static struct sigaction s_handlerFPE,
                            s_handlerILL,
                            s_handlerBUS,
                            s_handlerSEGV;

    bool ok = true;
    if ( doit && !s_savedHandlers )
    {
        // install the signal handler
        struct sigaction act;

        // some systems extend it with non std fields, so zero everything
        memset(&act, 0, sizeof(act));

        act.sa_handler = wxFatalSignalHandler;
        sigemptyset(&act.sa_mask);
        act.sa_flags = 0;

        ok &= sigaction(SIGFPE, &act, &s_handlerFPE) == 0;
        ok &= sigaction(SIGILL, &act, &s_handlerILL) == 0;
        ok &= sigaction(SIGBUS, &act, &s_handlerBUS) == 0;
        ok &= sigaction(SIGSEGV, &act, &s_handlerSEGV) == 0;
        if ( !ok )
        {
            wxLogDebug(_T("Failed to install our signal handler."));
        }

        s_savedHandlers = true;
    }
    else if ( s_savedHandlers )
    {
        // uninstall the signal handler
        ok &= sigaction(SIGFPE, &s_handlerFPE, NULL) == 0;
        ok &= sigaction(SIGILL, &s_handlerILL, NULL) == 0;
        ok &= sigaction(SIGBUS, &s_handlerBUS, NULL) == 0;
        ok &= sigaction(SIGSEGV, &s_handlerSEGV, NULL) == 0;
        if ( !ok )
        {
            wxLogDebug(_T("Failed to uninstall our signal handler."));
        }

        s_savedHandlers = false;
    }
    //else: nothing to do

    return ok;
}

#endif // wxUSE_ON_FATAL_EXCEPTION

// ----------------------------------------------------------------------------
// wxExecute support
// ----------------------------------------------------------------------------

bool wxAppTraits::CreateEndProcessPipe(wxExecuteData& execData)
{
    return execData.pipeEndProcDetect.Create();
}

bool wxAppTraits::IsWriteFDOfEndProcessPipe(wxExecuteData& execData, int fd)
{
    return fd == (execData.pipeEndProcDetect)[wxPipe::Write];
}

void wxAppTraits::DetachWriteFDOfEndProcessPipe(wxExecuteData& execData)
{
    execData.pipeEndProcDetect.Detach(wxPipe::Write);
    execData.pipeEndProcDetect.Close();
}

int wxAppTraits::AddProcessCallback(wxEndProcessData *data, int fd)
{
    // define a custom handler processing only the closure of the descriptor
    struct wxEndProcessFDIOHandler : public wxFDIOHandler
    {
        wxEndProcessFDIOHandler(wxEndProcessData *data, int fd)
            : m_data(data), m_fd(fd)
        {}

        virtual void OnReadWaiting()
            { wxFAIL_MSG("this isn't supposed to happen"); }
        virtual void OnWriteWaiting()
            { wxFAIL_MSG("this isn't supposed to happen"); }

        virtual void OnExceptionWaiting()
        {
            const int pid = m_data->pid > 0 ? m_data->pid : -(m_data->pid);
            int status = 0;

            // has the process really terminated?
            int rc = waitpid(pid, &status, WNOHANG);
            if ( rc == 0 )
            {
                // This can only happen if the child application closes our
                // dummy pipe that is used to monitor its lifetime; in that
                // case, our best bet is to pretend the process did terminate,
                // because otherwise wxExecute() would hang indefinitely
                // (OnExceptionWaiting() won't be called again, the descriptor
                // is closed now).
                wxLogDebug("Child process (PID %d) still alive, "
                           "even though pipe was closed.", pid);
            }
            else if ( rc == -1 )
            {
                // As above, if waitpid() fails, the best we can do is to log the
                // error and pretend the child terminated:
                wxLogSysError(_("Failed to check child process' status"));
            }

            // set exit code to -1 if something bad happened
            m_data->exitcode = rc > 0 && WIFEXITED(status) ? WEXITSTATUS(status)
                                                           : -1;

            wxLogTrace("exec",
                       "Child process (PID %d) terminated with exit code %d",
                       pid, m_data->exitcode);

            // child exited, end waiting
            wxFDIODispatcher::Get()->UnregisterFD(m_fd);
            close(m_fd);

            wxHandleProcessTermination(m_data);

            delete this;
        }

        wxEndProcessData * const m_data;
        const int m_fd;
    };

    wxFDIODispatcher::Get()->RegisterFD
                             (
                                 fd,
                                 new wxEndProcessFDIOHandler(data, fd),
                                 wxFDIO_EXCEPTION
                             );
    return fd; // unused, but return something unique for the tag
}

bool wxAppTraits::CheckForRedirectedIO(wxExecuteData& execData)
{
#if HAS_PIPE_INPUT_STREAM
    bool hasIO = false;

    if ( execData.bufOut && execData.bufOut->Update() )
        hasIO = true;

    if ( execData.bufErr && execData.bufErr->Update() )
        hasIO = true;

    return hasIO;
#else // !HAS_PIPE_INPUT_STREAM
    return false;
#endif // HAS_PIPE_INPUT_STREAM/!HAS_PIPE_INPUT_STREAM
}

class wxReadFDIOHandler : public wxFDIOHandler
{
public:
    wxReadFDIOHandler(wxFDIODispatcher& disp, int fd) : m_fd(fd)
    {
        if ( fd )
            disp.RegisterFD(fd, this, wxFDIO_INPUT);
    }

    int GetFD() const { return m_fd; }

    virtual void OnWriteWaiting() { wxFAIL_MSG("unreachable"); }
    virtual void OnExceptionWaiting() { wxFAIL_MSG("unreachable"); }

private:
    const int m_fd;

    DECLARE_NO_COPY_CLASS(wxReadFDIOHandler)
};

class wxEndHandler : public wxReadFDIOHandler
{
public:
    wxEndHandler(wxFDIODispatcher& disp, int fd)
        : wxReadFDIOHandler(disp, fd)
    {
        m_terminated = false;
    }

    bool Terminated() const { return m_terminated; }

    virtual void OnReadWaiting() { m_terminated = true; }

private:
    bool m_terminated;

    DECLARE_NO_COPY_CLASS(wxEndHandler)
};

#if wxUSE_STREAMS

class wxRedirectedIOHandler : public wxReadFDIOHandler
{
public:
    wxRedirectedIOHandler(wxFDIODispatcher& disp,
                          int fd,
                          wxStreamTempInputBuffer *buf)
        : wxReadFDIOHandler(disp, fd),
          m_buf(buf)
    {
    }

    virtual void OnReadWaiting()
    {
        m_buf->Update();
    }

private:
    wxStreamTempInputBuffer * const m_buf;

    DECLARE_NO_COPY_CLASS(wxRedirectedIOHandler)
};

#endif // wxUSE_STREAMS

int wxAppTraits::WaitForChild(wxExecuteData& execData)
{
    if ( !(execData.flags & wxEXEC_SYNC) )
    {
        // asynchronous execution: just launch the process and return
        wxEndProcessData *endProcData = new wxEndProcessData;
        endProcData->process  = execData.process;
        endProcData->pid      = execData.pid;
        endProcData->tag = AddProcessCallback
                           (
                             endProcData,
                             execData.GetEndProcReadFD()
                           );

        return execData.pid;
    }

#if wxUSE_STREAMS
    wxProcess * const process = execData.process;
    if ( process && process->IsRedirected() )
    {
        // we can't simply block waiting for the child to terminate as we would
        // dead lock if it writes more than the pipe buffer size (typically
        // 4KB) bytes of output -- it would then block waiting for us to read
        // the data while we'd block waiting for it to terminate
        //
        // so multiplex here waiting for any input from the child or closure of
        // the pipe used to indicate its termination
        wxSelectDispatcher disp;

        wxEndHandler endHandler(disp, execData.GetEndProcReadFD());

        wxRedirectedIOHandler outHandler(disp, execData.fdOut, execData.bufOut),
                              errHandler(disp, execData.fdErr, execData.bufErr);

        while ( !endHandler.Terminated() )
        {
            disp.Dispatch();
        }
    }
    //else: no IO redirection, just block waiting for the child to exit
#endif // wxUSE_STREAMS

    int status = 0;

    int result = waitpid(execData.pid, &status, 0);
#ifdef __DARWIN__
    /*  DE: waitpid manpage states that waitpid can fail with EINTR
        if the call is interrupted by a caught signal.  I suppose
        that means that this ought to be a while loop.

        The odd thing is that it seems to fail EVERY time.  It fails
        with a quickly exiting process (e.g. echo), and fails with a
        slowly exiting process (e.g. sleep 2) but clearly after
        having waited for the child to exit. Maybe it's a bug in
        my particular version.

        It works, however, from the CFSocket callback without this
        trick but in that case it's used only after CFSocket calls
        the callback and with the WNOHANG flag which would seem to
        preclude it from being interrupted or at least make it much
        less likely since it would not then be waiting.

        If Darwin's man page is to be believed then this is definitely
        necessary.  It's just weird that I've never seen it before
        and apparently no one else has either or you'd think they'd
        have reported it by now.  Perhaps blocking the GUI while
        waiting for a child process to exit is simply not that common.
     */
    if ( result == -1 && errno == EINTR )
    {
        result = waitpid(execData.pid, &status, 0);
    }
#endif // __DARWIN__

    if ( result == -1 )
    {
        wxLogLastError("waitpid");
    }
    else // child terminated
    {
        wxASSERT_MSG( result == execData.pid,
                      "unexpected waitpid() return value" );

        if ( WIFEXITED(status) )
        {
            return WEXITSTATUS(status);
        }
        else // abnormal termination?
        {
            wxASSERT_MSG( WIFSIGNALED(status),
                          "unexpected child wait status" );
        }
    }

    wxLogSysError(_("Waiting for subprocess termination failed"));

    return -1;
}

void wxHandleProcessTermination(wxEndProcessData *proc_data)
{
    // notify user about termination if required
    if ( proc_data->process )
    {
        proc_data->process->OnTerminate(proc_data->pid, proc_data->exitcode);
    }

    // clean up
    if ( proc_data->pid > 0 )
    {
        // async execution
        delete proc_data;
    }
    else // sync execution
    {
        // let wxExecute() know that the process has terminated
        proc_data->pid = 0;
    }
}