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

/////////////////////////////////////////////////////////////////////////////
// Name:        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
// ----------------------------------------------------------------------------

#include "wx/defs.h"
#include "wx/string.h"

#include "wx/intl.h"
#include "wx/log.h"
#include "wx/app.h"

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

#include "wx/wfstream.h"

#ifdef HAVE_STATFS
#  ifdef __BSD__
#    include <sys/param.h>
#    include <sys/mount.h>
#  else
#    include <sys/vfs.h>
#  endif
#endif // HAVE_STATFS

// not only the statfs syscall is called differently depending on platform, but
// we also can't use "struct statvfs" under Solaris because it breaks down if
// HAVE_LARGEFILE_SUPPORT == 1 and we must use statvfs_t instead
#ifdef HAVE_STATVFS
    #include <sys/statvfs.h>

    #define statfs statvfs
    #define wxStatFs statvfs_t
#elif HAVE_STATFS
    #define wxStatFs struct statfs
#endif // HAVE_STAT[V]FS

#if wxUSE_GUI
    #include "wx/unix/execute.h"
#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 <unistd.h>
#include <sys/wait.h>
#include <pwd.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

// ----------------------------------------------------------------------------
// 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 __SUN__
            int usleep(unsigned int usec);
        #else // !Sun
            #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 // !Sun && !EMX
                void usleep(unsigned long usec);
            #endif
        #endif // Sun/EMX/Something else
    };

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

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

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

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

void wxUsleep(unsigned long milliseconds)
{
#if defined(HAVE_NANOSLEEP)
    timespec tmReq;
    tmReq.tv_sec = (time_t)(milliseconds / 1000);
    tmReq.tv_nsec = (milliseconds % 1000) * 1000 * 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(milliseconds * 1000); // usleep(3) wants microseconds
#elif defined(HAVE_SLEEP)
    // under BeOS sleep() takes seconds (what about other platforms, if any?)
    sleep(milliseconds * 1000);
#else // !sleep function
    #error "usleep() or nanosleep() function required for wxUsleep"
#endif // sleep function
}

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

int wxKill(long pid, wxSignal sig, wxKillError *rc)
{
    int err = kill((pid_t)pid, (int)sig);
    if ( rc )
    {
        switch ( errno )
        {
            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

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

    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=wxT("");
        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;

    // do execute the command
#if wxUSE_UNICODE
    long lRc = -1;
#else
    long lRc = wxExecute(argv, flags, process);
#endif

    // 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, 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;
}


#if wxUSE_GUI

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 )
    {
       delete proc_data;
    }
    else
    {
       // let wxExecute() know that the process has terminated
       proc_data->pid = 0;
    }
}

#endif // wxUSE_GUI

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

#if wxUSE_STREAMS

// ----------------------------------------------------------------------------
// wxProcessFileInputStream: stream for reading from a pipe
// ----------------------------------------------------------------------------

class wxProcessFileInputStream : public wxFileInputStream
{
public:
    wxProcessFileInputStream(int fd) : wxFileInputStream(fd) { }

    // return TRUE if we have anything to read, don't block
    bool IsAvailable() const;
};

bool wxProcessFileInputStream::IsAvailable() const
{
    if ( m_lasterror == wxSTREAM_EOF )
        return TRUE;

    // 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;
    FD_ZERO(&readfds);
    FD_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 TRUE;

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

        case 1:
            // input available
            return TRUE;
    }
}

// ----------------------------------------------------------------------------
// wxStreamTempInputBuffer
// ----------------------------------------------------------------------------

/*
   Extract of a mail to wx-users to give the context of the problem we are
   trying to solve here:

    MC> If I run the command:
    MC>    find . -name "*.h" -exec grep linux {} \;
    MC> in the exec sample synchronously from the 'Capture command output'
    MC> menu, wxExecute never returns.  I have to xkill it.  Has anyone
    MC> else encountered this?

     Yes, I can reproduce it too.

     I even think I understand why it happens: before launching the external
    command we set up a pipe with a valid file descriptor on the reading side
    when the output is redirected. So the subprocess happily writes to it ...
    until the pipe buffer (which is usually quite big on Unix, I think the
    default is 4Kb) is full. Then the writing process stops and waits until we
    read some data from the pipe to be able to continue writing to it but we
    never do it because we wait until it terminates to start reading and so we
    have a classical deadlock.

   Here is the fix: we now read the output as soon as it appears into a temp
   buffer (wxStreamTempInputBuffer object) and later just stuff it back into the
   stream when the process terminates. See supporting code in wxExecute()
   itself as well.

   Note that this is horribly inefficient for large amounts of output (count
   the number of times we copy the data around) and so a better API is badly
   needed!
*/

class wxStreamTempInputBuffer
{
public:
    wxStreamTempInputBuffer();

    // call to associate a stream with this buffer, otherwise nothing happens
    // at all
    void Init(wxProcessFileInputStream *stream);

    // check for input on our stream and cache it in our buffer if any
    void Update();

    ~wxStreamTempInputBuffer();

private:
    // the stream we're buffering, if NULL we don't do anything at all
    wxProcessFileInputStream *m_stream;

    // the buffer of size m_size (NULL if m_size == 0)
    void *m_buffer;

    // the size of the buffer
    size_t m_size;
};

wxStreamTempInputBuffer::wxStreamTempInputBuffer()
{
    m_stream = NULL;
    m_buffer = NULL;
    m_size = 0;
}

void wxStreamTempInputBuffer::Init(wxProcessFileInputStream *stream)
{
    m_stream = stream;
}

void wxStreamTempInputBuffer::Update()
{
    if ( m_stream && m_stream->IsAvailable() )
    {
        // realloc in blocks of 4Kb: this is the default (and minimal) buffer
        // size of the Unix pipes so it should be the optimal step
        static const size_t incSize = 4096;

        void *buf = realloc(m_buffer, m_size + incSize);
        if ( !buf )
        {
            // don't read any more, we don't have enough memory to do it
            m_stream = NULL;
        }
        else // got memory for the buffer
        {
            m_buffer = buf;
            m_stream->Read((char *)m_buffer + m_size, incSize);
            m_size += m_stream->LastRead();
        }
    }
}

wxStreamTempInputBuffer::~wxStreamTempInputBuffer()
{
    if ( m_buffer )
    {
        m_stream->Ungetch(m_buffer, m_size);
        free(m_buffer);
    }
}

#endif // wxUSE_STREAMS

// ----------------------------------------------------------------------------
// wxPipe: this encapsulates pipe() system call
// ----------------------------------------------------------------------------

class wxPipe
{
public:
    // the symbolic names for the pipe ends
    enum Direction
    {
        Read,
        Write
    };

    enum
    {
        INVALID_FD = -1
    };

    // default ctor doesn't do anything
    wxPipe() { m_fds[Read] = m_fds[Write] = INVALID_FD; }

    // create the pipe, return TRUE if ok, FALSE on error
    bool Create()
    {
        if ( pipe(m_fds) == -1 )
        {
            wxLogSysError(_("Pipe creation failed"));

            return FALSE;
        }

        return TRUE;
    }

    // return TRUE if we were created successfully
    bool IsOk() const { return m_fds[Read] != INVALID_FD; }

    // return the descriptor for one of the pipe ends
    int operator[](Direction which) const
    {
        wxASSERT_MSG( which >= 0 && (size_t)which < WXSIZEOF(m_fds),
                      _T("invalid pipe index") );

        return m_fds[which];
    }

    // detach a descriptor, meaning that the pipe dtor won't close it, and
    // return it
    int Detach(Direction which)
    {
        wxASSERT_MSG( which >= 0 && (size_t)which < WXSIZEOF(m_fds),
                      _T("invalid pipe index") );

        int fd = m_fds[which];
        m_fds[which] = INVALID_FD;

        return fd;
    }

    // close the pipe descriptors
    void Close()
    {
        for ( size_t n = 0; n < WXSIZEOF(m_fds); n++ )
        {
            if ( m_fds[n] != INVALID_FD )
                close(m_fds[n]);
        }
    }

    // dtor closes the pipe descriptors
    ~wxPipe() { Close(); }

private:
    int m_fds[2];
};

// ----------------------------------------------------------------------------
// wxExecute: the real worker function
// ----------------------------------------------------------------------------
#ifdef __VMS
#pragma message disable codeunreachable
#endif

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 = wxConvertWX2MB(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

#if wxUSE_GUI
    // create pipes
    wxPipe pipeEndProcDetect;
    if ( !pipeEndProcDetect.Create() )
    {
        wxLogError( _("Failed to execute '%s'\n"), *argv );

        ARGS_CLEANUP;

        return ERROR_RETURN_CODE;
    }
#endif // wxUSE_GUI

    // 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
#ifdef HAVE_VFORK
    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) )
        {
            for ( int fd = 0; fd < FD_SETSIZE; fd++ )
            {
                if ( fd == pipeIn[wxPipe::Read]
                        || fd == pipeOut[wxPipe::Write]
                        || fd == pipeErr[wxPipe::Write]
#if wxUSE_GUI
                        || fd == pipeEndProcDetect[wxPipe::Write]
#endif // wxUSE_GUI
                   )
                {
                    // 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);
            }
        }

#ifndef __VMS
        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

#if wxUSE_GUI
        // reading side can be safely closed but we should keep the write one
        // opened
        pipeEndProcDetect.Detach(wxPipe::Write);
        pipeEndProcDetect.Close();
#endif // wxUSE_GUI

        // 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);

        // 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;

        // prepare for IO redirection

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

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

            wxProcessFileInputStream *outStream =
                new wxProcessFileInputStream(pipeOut.Detach(wxPipe::Read));

            wxProcessFileInputStream *errStream =
                new wxProcessFileInputStream(pipeErr.Detach(wxPipe::Read));

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

            bufOut.Init(outStream);
            bufErr.Init(errStream);
#endif // wxUSE_STREAMS
        }

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

#if wxUSE_GUI && !defined(__WXMICROWIN__)
        wxEndProcessData *data = new wxEndProcessData;

        data->tag = wxAddProcessCallback
                    (
                        data,
                        pipeEndProcDetect.Detach(wxPipe::Read)
                    );

        pipeEndProcDetect.Close();

        if ( flags & wxEXEC_SYNC )
        {
            // we may have process for capturing the program output, but it's
            // not used in wxEndProcessData in the case of sync execution
            data->process = NULL;

            // sync execution: indicate it by negating the pid
            data->pid = -pid;

            wxBusyCursor bc;
            wxWindowDisabler wd;

            // data->pid will be set to 0 from GTK_EndProcessDetector when the
            // process terminates
            while ( data->pid != 0 )
            {
#if wxUSE_STREAMS
                bufOut.Update();
                bufErr.Update();
#endif // wxUSE_STREAMS

                // give GTK+ a chance to call GTK_EndProcessDetector here and
                // also repaint the GUI
                wxYield();
            }

            int exitcode = data->exitcode;

            delete data;

            return exitcode;
        }
        else // async execution
        {
            // async execution, nothing special to do - caller will be
            // notified about the process termination if process != NULL, data
            // will be deleted in GTK_EndProcessDetector
            data->process  = process;
            data->pid      = pid;

            return pid;
        }
#else // !wxUSE_GUI

        wxASSERT_MSG( flags & wxEXEC_SYNC,
                      wxT("async execution not supported yet") );

        int exitcode = 0;
        if ( waitpid(pid, &exitcode, 0) == -1 || !WIFEXITED(exitcode) )
        {
            wxLogSysError(_("Waiting for subprocess termination failed"));
        }

        return exitcode;
#endif // wxUSE_GUI
    }

    return ERROR_RETURN_CODE;
}
#ifdef __VMS
#pragma message enable codeunreachable
#endif

#undef ERROR_RETURN_CODE
#undef ARGS_CLEANUP

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

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

#if wxUSE_UNICODE
const wxMB2WXbuf wxGetUserHome( const wxString &user )
#else // just for binary compatibility -- there is no 'const' here
char *wxGetUserHome( const wxString &user )
#endif
{
    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(wxConvertWX2MB(ptr));
        }

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

    return wxConvertMB2WX(who ? who->pw_dir : 0);
}

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

// 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, wxConvertMB2WX(uts.nodename), sz - 1);
        buf[sz] = wxT('\0');
    }
#elif defined(HAVE_GETHOSTNAME)
    bool ok = gethostname(buf, sz) != -1;
#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(wxConvertWX2MB(buf));
            if ( !host )
            {
                wxLogSysError(_("Cannot get the official hostname"));

                ok = FALSE;
            }
            else
            {
                // the canonical name
                wxStrncpy(buf, wxConvertMB2WX(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, wxConvertMB2WX(who->pw_name), sz - 1);
        return TRUE;
    }

    return FALSE;
}

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

    *buf = wxT('\0');
    if ((who = getpwuid (getuid ())) != NULL)
    {
        // pw_gecos field in struct passwd is not standard
#ifdef HAVE_PW_GECOS
       char *comma = strchr(who->pw_gecos, ',');
       if (comma)
           *comma = '\0'; // cut off non-name comment fields
       wxStrncpy (buf, wxConvertMB2WX(who->pw_gecos), sz - 1);
#else // !HAVE_PW_GECOS
       wxStrncpy (buf, wxConvertMB2WX(who->pw_name), sz - 1);
#endif // HAVE_PW_GECOS/!HAVE_PW_GECOS
       return TRUE;
    }

    return FALSE;
}

#ifndef __WXMAC__
wxString wxGetOsDescription()
{
#ifndef WXWIN_OS_DESCRIPTION
    #error WXWIN_OS_DESCRIPTION should be defined in config.h by configure
#else
    return WXWIN_OS_DESCRIPTION;
#endif
}
#endif

// this function returns the GUI toolkit version in GUI programs, but OS
// version in non-GUI ones
#if !wxUSE_GUI

int wxGetOsVersion(int *majorVsn, int *minorVsn)
{
    int major, minor;
    char name[256];

    if ( sscanf(WXWIN_OS_DESCRIPTION, "%s %d.%d", name, &major, &minor) != 3 )
    {
        // unreckognized uname string format
        major = minor = -1;
    }

    if ( majorVsn )
        *majorVsn = major;
    if ( minorVsn )
        *minorVsn = minor;

    return wxUNIX;
}

#endif // !wxUSE_GUI

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

long 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) )
        {
            long memTotal, memUsed;
            sscanf(buf, "Mem: %ld %ld %ld", &memTotal, &memUsed, &memFree);
        }

        fclose(fp);

        return memFree;
    }
#elif defined(__SUN__) && defined(_SC_AVPHYS_PAGES)
    return 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, wxLongLong *pTotal, wxLongLong *pFree)
{
#if defined(HAVE_STATFS) || defined(HAVE_STATVFS)
    // the case to "char *" is needed for AIX 4.3
    wxStatFs fs;
    if ( statfs((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
    wxLongLong blockSize = fs.f_frsize;
#else // HAVE_STATFS
    wxLongLong blockSize = fs.f_bsize;
#endif // HAVE_STATVFS/HAVE_STATFS

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

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

    return TRUE;
#else // !HAVE_STATFS && !HAVE_STATVFS
    return FALSE;
#endif // HAVE_STATFS
}

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

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

    if ( value )
    {
        *value = p;
    }

    return TRUE;
}

bool wxSetEnv(const wxString& variable, const wxChar *value)
{
#if defined(HAVE_SETENV)
    return setenv(variable.mb_str(),
                  value ? (const char *)wxString(value).mb_str()
                        : NULL,
                  1 /* overwrite */) == 0;
#elif defined(HAVE_PUTENV)
    wxString s = variable;
    if ( value )
        s << _T('=') << value;

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

    // the string will be free()d by libc
    char *buf = (char *)malloc(strlen(p) + 1);
    strcpy(buf, p);

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

// ----------------------------------------------------------------------------
// 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

// ----------------------------------------------------------------------------
// error and debug output routines (deprecated, use wxLog)
// ----------------------------------------------------------------------------

#if WXWIN_COMPATIBILITY_2_2

void wxDebugMsg( const char *format, ... )
{
  va_list ap;
  va_start( ap, format );
  vfprintf( stderr, format, ap );
  fflush( stderr );
  va_end(ap);
}

void wxError( const wxString &msg, const wxString &title )
{
  wxFprintf( stderr, _("Error ") );
  if (!title.IsNull()) wxFprintf( stderr, wxT("%s "), WXSTRINGCAST(title) );
  if (!msg.IsNull()) wxFprintf( stderr, wxT(": %s"), WXSTRINGCAST(msg) );
  wxFprintf( stderr, wxT(".\n") );
}

void wxFatalError( const wxString &msg, const wxString &title )
{
  wxFprintf( stderr, _("Error ") );
  if (!title.IsNull()) wxFprintf( stderr, wxT("%s "), WXSTRINGCAST(title) );
  if (!msg.IsNull()) wxFprintf( stderr, wxT(": %s"), WXSTRINGCAST(msg) );
  wxFprintf( stderr, wxT(".\n") );
  exit(3); // the same exit code as for abort()
}

#endif // WXWIN_COMPATIBILITY_2_2