freepascal.compiler/rtl/unix/unix.pp

{
   This file is part of the Free Pascal run time library.
   Copyright (c) 1999-2000 by Michael Van Canneyt,
   BSD parts (c) 2000 by Marco van de Voort
   members of the Free Pascal development team.

   See the file COPYING.FPC, included in this distribution,
   for details about the copyright.

   This program 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.

**********************************************************************}
Unit Unix;
Interface

Uses BaseUnix,UnixType;

{$if (defined(BSD) or defined(SUNOS)) and defined(FPC_USE_LIBC)}
{$define USE_VFORK}
{$endif}

{$i aliasptp.inc}

{ Get Types and Constants only exported in this unit }
{$i unxconst.inc}

// We init to zero to be able to put timezone stuff under IFDEF, and still
// keep the code working.
// We can't do this hear, since unixutil functions access this.

// var
//  Tzseconds : Longint = 0;


{********************
      File
********************}

Const
  P_IN  = 1;                    // pipes (?)
  P_OUT = 2;

Const
  LOCK_SH = 1;                  // flock constants ?
  LOCK_EX = 2;
  LOCK_UN = 8;
  LOCK_NB = 4;

Type
  Tpipe = baseunix.tfildes;     // compability.

{******************************************************************************
                            Procedure/Functions
******************************************************************************}

{**************************
     Time/Date Handling
***************************}

var
  tzdaylight : boolean;
  tzname     : array[boolean] of pchar;

{$IFNDEF DONT_READ_TIMEZONE}  // allows to disable linking in and trying for platforms
                       // it doesn't (yet) work for.

{ timezone support }
procedure GetLocalTimezone(timer:cint;var leap_correct,leap_hit:cint);
procedure GetLocalTimezone(timer:cint);
procedure ReadTimezoneFile(fn:string);
function  GetTimezoneFile:string;
{$ENDIF}

{**************************
     Process Handling
***************************}

//
// These are much better, in nearly all ways.
//

function FpExecLE (Const PathName:AnsiString;const S:Array Of AnsiString;MyEnv:ppchar):cint;
function FpExecL(Const PathName:AnsiString;const S:Array Of AnsiString):cint;
function FpExecLP(Const PathName:AnsiString;const S:Array Of AnsiString):cint;
function FpExecV(Const PathName:AnsiString;args:ppchar):cint;
function FpExecVP(Const PathName:AnsiString;args:ppchar):cint;
function FpExecVPE(Const PathName:AnsiString;args,env:ppchar):cint;

Function Shell   (const Command:String):cint;     deprecated;
Function Shell   (const Command:AnsiString):cint; deprecated;
Function fpSystem(const Command:string):cint;
Function fpSystem(const Command:AnsiString):cint;

Function WaitProcess (Pid:cint):cint; 
{ like WaitPid(PID,@result,0) Handling of Signal interrupts (errno=EINTR), returning the Exitcode of Process (>=0) or -Status if terminated}

Function WIFSTOPPED (Status: Integer): Boolean;
Function W_EXITCODE (ReturnCode, Signal: Integer): Integer;
Function W_STOPCODE (Signal: Integer): Integer;

{**************************
     File Handling
***************************}

{$ifndef FPC_USE_LIBC} // defined using cdecl for libc.
Function  fsync (fd : cint) : cint;
Function  fpFlock   (fd,mode : cint)   : cint ;
Function  fStatFS (Fd: cint;Var Info:tstatfs):cint;
Function  StatFS  (Path:pchar;Var Info:tstatfs):cint;
{$endif}

Function  fpFlock   (var T : text;mode : cint) : cint;
Function  fpFlock   (var F : File;mode : cint) : cint;

Function  SelectText (var T:Text;TimeOut :PTimeVal):cint; deprecated;
Function  SelectText (var T:Text;TimeOut :cint):cint; deprecated;

{**************************
   Directory Handling
***************************}

procedure SeekDir(p:pdir;loc:clong);
function  TellDir(p:pdir):TOff;

{**************************
    Pipe/Fifo/Stream
***************************}

Function AssignPipe  (var pipe_in,pipe_out:cint):cint;
Function AssignPipe  (var pipe_in,pipe_out:text):cint;
Function AssignPipe  (var pipe_in,pipe_out:file):cint;
//Function PClose      (Var F:text) : cint;
//Function PClose      (Var F:file) : cint;
Function POpen       (var F:text;const Prog:Ansistring;rw:char):cint;
Function POpen       (var F:file;const Prog:Ansistring;rw:char):cint;
Function AssignStream(Var StreamIn,Streamout:text;Const Prog:ansiString;const args : array of ansistring) : cint;
Function AssignStream(Var StreamIn,Streamout,streamerr:text;Const Prog:ansiString;const args : array of ansistring) : cint;

Function  GetDomainName:String;
Function  GetHostName:String;


{**************************
     Memory functions
***************************}

Const
// The portable MAP_* and PROT_ constants are exported from unit Unix for compability.

  PROT_READ  = baseunix.PROT_READ;             { page can be read }
  PROT_WRITE = baseunix.PROT_WRITE;             { page can be written }
  PROT_EXEC  = baseunix.PROT_EXEC;             { page can be executed }
  PROT_NONE  = baseunix.PROT_NONE;             { page can not be accessed }

  MAP_FAILED    = baseunix.MAP_FAILED;	      { mmap() failed }
  MAP_SHARED    = baseunix.MAP_SHARED;        { Share changes }
  MAP_PRIVATE   = baseunix.MAP_PRIVATE;       { Changes are private }
  MAP_TYPE      = baseunix.MAP_TYPE;          { Mask for type of mapping }
  MAP_FIXED     = baseunix.MAP_FIXED;         { Interpret addr exactly }

{ Flags to `msync'.  }
  MS_ASYNC        = 1;               { Sync memory asynchronously.  }
  MS_SYNC         = 4;               { Synchronous memory sync.  }
  MS_INVALIDATE   = 2;               { Invalidate the caches.  }

{**************************
    Utility functions
***************************}

Type
        TFSearchOption  = (NoCurrentDirectory,
                           CurrentDirectoryFirst,
                           CurrentDirectoryLast);

Function  FSearch  (const path:AnsiString;dirlist:Ansistring;CurrentDirStrategy:TFSearchOption):AnsiString;
Function  FSearch  (const path:AnsiString;dirlist:AnsiString):AnsiString;

procedure SigRaise (sig:integer);

{$ifdef FPC_USE_LIBC}
  const clib = 'c';
  {$i unxdeclh.inc}
{$else}
  {$i unxsysch.inc} //  calls used in system and not reexported from baseunix
{$endif}

{******************************************************************************
                            Implementation
******************************************************************************}

{$i unxovlh.inc}

Implementation

Uses UnixUtil,  // tzseconds
     Strings {$ifndef FPC_USE_LIBC},Syscall{$endif};

{$i unxovl.inc}

{$ifndef FPC_USE_LIBC}
  {$i syscallh.inc}
  {$i unxsysc.inc}
{$endif}

{ Get the definitions of textrec and filerec }
{$i textrec.inc}
{$i filerec.inc}

{$i unxfunc.inc}   { Platform specific implementations }

Function getenv(name:string):Pchar; external name 'FPC_SYSC_FPGETENV';

{******************************************************************************
                          Process related calls
******************************************************************************}

{ Most calls of WaitPID do not handle the result correctly, this funktion treats errors more correctly }
Function  WaitProcess(Pid:cint):cint; { like WaitPid(PID,@result,0) Handling of Signal interrupts (errno=EINTR), returning the Exitcode of Process (>=0) or -Status if terminated}
var
  r,s     : cint;
begin
  s:=$7F00;

  repeat
    r:=fpWaitPid(Pid,@s,0);
    if (r=-1) and (fpgeterrno=ESysEIntr) Then
      r:=0;
  until (r<>0);
  if (r=-1) or (r=0) then // 0 is not a valid return and should never occur (it means status invalid when using WNOHANG)
    WaitProcess:=-1 // return -1 to indicate an error.  fpwaitpid updated it.
  else
   begin
     if wifexited(s) then
      WaitProcess:=wexitstatus(s)
     else if (s>0) then  // Until now there is not use of the highest bit , but check this for the future
      WaitProcess:=-s // normal case
     else
      WaitProcess:=s; // s<0 should not occur, but wie return also a negativ value
   end;
end;

function intFpExecVEMaybeP (Const PathName:AnsiString;Args,MyEnv:ppchar;SearchPath:Boolean):cint;
// does an ExecVE, but still has to handle P
// execv variants call this directly, execl variants indirectly via
//     intfpexecl

Var
  NewCmd  : ansistring;
  ThePath : AnsiString;

Begin
  If SearchPath and (pos('/',pathname)=0) Then
    Begin
      // The above could be better. (check if not escaped/quoted '/'s) ?
      // (Jilles says this is ok)
      // Stevens says only search if newcmd contains no '/'
      // fsearch is not ansistring clean yet.
      ThePath:=fpgetenv('PATH');
      if thepath='' then
        thepath:='.';     // FreeBSD uses _PATH_DEFPATH = /usr/bin:/bin
                          // but a quick check showed that _PATH_DEFPATH
                          // varied from OS to OS

      newcmd:=FSearch(pathname,thepath,NoCurrentDirectory);
      // FreeBSD libc keeps on trying till a file is successfully run.
      // Stevens says "try each path prefix"

      // execp puts newcmd here.
        args^:=pchar(newcmd);
   End else
      newcmd:=pathname;
 // repeat
//      if searchpath then args^:=pchar(commandtorun)

  IntFpExecVEMaybeP:=fpExecVE(newcmd,Args,MyEnv);
{
// Code that if exec fails due to permissions, tries to run it with sh
// Should we deallocate p on fail? -> no fpexit is run no matter what
//
}
// if intfpexecvemaybep=-1 then zoekvolgende file.
// until (Goexit) or SearchExit;


{
 If IntFpExec=-1 Then
    Begin
      Error:=fpGetErrno
      Case Error of
        ESysE2Big  : Exit(-1);
        ESysELoop,
          : Exit(-1);

}
end;

function intFpExecl (Const PathName:AnsiString;const s:array of ansistring;MyEnv:ppchar;SearchPath:Boolean):cint;
{ Handles the array of ansistring -> ppchar conversion.
  Base for the the "l" variants.
}
var p:ppchar;

begin
  If PathName='' Then
    Begin
      fpsetErrno(ESysEnoEnt);
      Exit(-1);                 // Errno?
    End;
  p:=ArrayStringToPPchar(s,1);
  if p=NIL Then
    Begin
      GetMem(p,2*sizeof(pchar));
      if p=nil then
       begin
        {$ifdef xunix}
          fpseterrno(ESysEnoMem);
        {$endif}
         fpseterrno(ESysEnoEnt);
         exit(-1);
       end;
      p[1]:=nil;
    End;
  p^:=pchar(PathName);
  IntFPExecL:=intFpExecVEMaybeP(PathName,p,MyEnv,SearchPath);
  // If we come here, no attempts were executed successfully.
  Freemem(p);
end;

function FpExecLE (Const PathName:AnsiString;const S:Array Of AnsiString;MyEnv:ppchar):cint;

Begin
  FpExecLE:=intFPExecl(PathName,s,MyEnv,false);
End;

function FpExecL(Const PathName:AnsiString;const S:Array Of AnsiString):cint;

Begin
  FpExecL:=intFPExecl(PathName,S,EnvP,false);
End;

function FpExecLP(Const PathName:AnsiString;const S:Array Of AnsiString):cint;

Begin
  FpExecLP:=intFPExecl(PathName,S,EnvP,True);
End;

function FpExecV(Const PathName:AnsiString;args:ppchar):cint;

Begin
 fpexecV:=intFpExecVEMaybeP (PathName,args,envp,false);
End;

function FpExecVP(Const PathName:AnsiString;args:ppchar):cint;

Begin
 fpexecVP:=intFpExecVEMaybeP (PathName,args,envp,true);
End;

function FpExecVPE(Const PathName:AnsiString;args,env:ppchar):cint;

Begin
 fpexecVPE:=intFpExecVEMaybeP (PathName,args,env,true);
End;

// exect and execvP (ExecCapitalP) are not implement
// Non POSIX anyway.
// Exect turns on tracing for the process
// execvP has the searchpath as array of ansistring ( const char *search_path)

{$define FPC_USE_FPEXEC}
{$if defined(FPC_USE_FPEXEC) and not defined(USE_VFORK)}
{$define SHELL_USE_FPEXEC}
{$endif}
Function Shell(const Command:String):cint; deprecated;
{
  Executes the shell, and passes it the string Command. (Through /bin/sh -c)
  The current environment is passed to the shell.
  It waits for the shell to exit, and returns its exit status.
  If the Exec call failed exit status 127 is reported.
}
{ Changed the structure:
- the previous version returns an undefinied value if fork fails
- it returns the status of Waitpid instead of the Process returnvalue (see the doc to Shell)
- it uses exit(127) not ExitProc (The Result in pp386: going on Compiling in 2 processes!)
- ShellArgs are now released
- The Old CreateShellArg gives back pointers to a local var
}
var
{$ifndef SHELL_USE_FPEXEC}
  p      : ppchar;
{$endif}
  pid    : cint;
begin
 {$ifndef SHELL_USE_FPEXEC}
  p:=CreateShellArgv(command);
{$endif}
{$ifdef USE_VFORK}
  pid:=fpvfork;
{$else USE_VFORK}
  pid:=fpfork;
{$endif USE_VFORK}
  if pid=0 then // We are in the Child
   begin
     {This is the child.}
     {$ifndef SHELL_USE_FPEXEC}
       fpExecve(p^,p,envp);
     {$else}
      fpexecl('/bin/sh',['-c',Command]);
     {$endif}
     fpExit(127);  // was Exit(127)
   end
  else if (pid<>-1) then // Successfull started
   Shell:=WaitProcess(pid)
  else // no success
   Shell:=-1; // indicate an error
  {$ifndef SHELL_USE_FPEXEC}
  FreeShellArgV(p);
  {$endif}
end;

Function Shell(const Command:AnsiString):cint;
{
  AnsiString version of Shell
}
var
{$ifndef SHELL_USE_FPEXEC}
  p     : ppchar;
{$endif}
  pid   : cint;
begin { Changes as above }
{$ifndef SHELL_USE_FPEXEC}
  p:=CreateShellArgv(command);
{$endif}
{$ifdef USE_VFORK}
  pid:=fpvfork;
{$else USE_VFORK}
  pid:=fpfork;
{$endif USE_VFORK}
  if pid=0 then // We are in the Child
   begin
    {$ifdef SHELL_USE_FPEXEC}
      fpexecl('/bin/sh',['-c',Command]);
    {$else}
     fpExecve(p^,p,envp);
    {$endif}
     fpExit(127); // was exit(127)!! We must exit the Process, not the function
   end
  else if (pid<>-1) then // Successfull started
   Shell:=WaitProcess(pid)
  else // no success
   Shell:=-1;
 {$ifndef SHELL_USE_FPEXEC}
  FreeShellArgV(p);
 {$ENDIF}
end;


{$ifdef FPC_USE_LIBC}
function xfpsystem(p:pchar):cint; cdecl; external clib name 'system';

function fpsystem(const Command:string):cint;

var c:array[0..255] of char;

begin
  strpcopy(@c,command);
  fpsystem:=xfpsystem(@c);
end;

Function fpSystem(const Command:AnsiString):cint;
begin
  fpsystem:=xfpsystem(pchar(command));
end;

{$else}
Function fpSystem(const Command:string):cint;

var
  pid,savedpid   : cint;
  pstat          : cint;
  ign,intact,
  quitact        : SigactionRec;
  newsigblock,
  oldsigblock    : tsigset;

begin { Changes as above }
  if command='' then exit(1);
  ign.sa_handler:=SigActionHandler(SIG_IGN);
  fpsigemptyset(ign.sa_mask);
  ign.sa_flags:=0;
  fpsigaction(SIGINT, @ign, @intact);
  fpsigaction(SIGQUIT, @ign, @quitact);
  fpsigemptyset(newsigblock);
  fpsigaddset(newsigblock,SIGCHLD);
  fpsigprocmask(SIG_BLOCK,newsigblock,oldsigblock);
  pid:=fpfork;
  if pid=0 then // We are in the Child
   begin
     fpsigaction(SIGINT,@intact,NIL);
     fpsigaction(SIGQUIT,@quitact,NIL);
     fpsigprocmask(SIG_SETMASK,@oldsigblock,NIL);
     fpexecl('/bin/sh',['-c',Command]);
     fpExit(127); // was exit(127)!! We must exit the Process, not the function
   end
  else if (pid<>-1) then // Successfull started
     begin
        savedpid:=pid;
        repeat
          pid:=fpwaitpid(savedpid,@pstat,0);
        until (pid<>-1) and (fpgeterrno()<>ESysEintr);
        if pid=-1 Then
         fpsystem:=-1
        else
         fpsystem:=pstat;
     end
  else // no success
   fpsystem:=-1;
  fpsigaction(SIGINT,@intact,NIL);
  fpsigaction(SIGQUIT,@quitact,NIL);
  fpsigprocmask(SIG_SETMASK,@oldsigblock,NIL);
end;

Function fpSystem(const Command:AnsiString):cint;
{
  AnsiString version of Shell
}
var
  pid,savedpid   : cint;
  pstat          : cint;
  ign,intact,
  quitact        : SigactionRec;
  newsigblock,
  oldsigblock    : tsigset;

begin { Changes as above }
  if command='' then exit(1);
  ign.sa_handler:=SigActionHandler(SIG_IGN);
  fpsigemptyset(ign.sa_mask);
  ign.sa_flags:=0;
  fpsigaction(SIGINT, @ign, @intact);
  fpsigaction(SIGQUIT, @ign, @quitact);
  fpsigemptyset(newsigblock);
  fpsigaddset(newsigblock,SIGCHLD);
  fpsigprocmask(SIG_BLOCK,newsigblock,oldsigblock);
  pid:=fpfork;
  if pid=0 then // We are in the Child
   begin
     fpsigaction(SIGINT,@intact,NIL);
     fpsigaction(SIGQUIT,@quitact,NIL);
     fpsigprocmask(SIG_SETMASK,@oldsigblock,NIL);
     fpexecl('/bin/sh',['-c',Command]);
     fpExit(127); // was exit(127)!! We must exit the Process, not the function
   end
  else if (pid<>-1) then // Successfull started
     begin
        savedpid:=pid;
        repeat
          pid:=fpwaitpid(savedpid,@pstat,0);
        until (pid<>-1) and (fpgeterrno()<>ESysEintr);
        if pid=-1 Then
         fpsystem:=-1
        else
         fpsystem:=pstat;
     end
  else // no success
   fpsystem:=-1;
  fpsigaction(SIGINT,@intact,NIL);
  fpsigaction(SIGQUIT,@quitact,NIL);
  fpsigprocmask(SIG_SETMASK,@oldsigblock,NIL);
end;
{$endif}

Function WIFSTOPPED(Status: Integer): Boolean;
begin
  WIFSTOPPED:=((Status and $FF)=$7F);
end;

Function W_EXITCODE(ReturnCode, Signal: Integer): Integer;
begin
  W_EXITCODE:=(ReturnCode shl 8) or Signal;
end;

Function W_STOPCODE(Signal: Integer): Integer;

begin
  W_STOPCODE:=(Signal shl 8) or $7F;
end;


{$IFNDEF DONT_READ_TIMEZONE}
{ Include timezone handling routines which use /usr/share/timezone info }
{$i timezone.inc}
{$endif}
{******************************************************************************
                           FileSystem calls
******************************************************************************}

Function fpFlock (var T : text;mode : cint) : cint;
begin
  fpFlock:=fpFlock(TextRec(T).Handle,mode);
end;


Function  fpFlock (var F : File;mode : cint) :cint;
begin
  fpFlock:=fpFlock(FileRec(F).Handle,mode);
end;

Function SelectText(var T:Text;TimeOut :PTimeval):cint;
Var
  F:TfdSet;
begin
  if textrec(t).mode=fmclosed then
   begin
     fpseterrno(ESysEBADF);
     exit(-1);
   end;
  FpFD_ZERO(f);
  fpFD_SET(textrec(T).handle,f);
  if textrec(T).mode=fminput then
   SelectText:=fpselect(textrec(T).handle+1,@f,nil,nil,TimeOut)
  else
   SelectText:=fpselect(textrec(T).handle+1,nil,@f,nil,TimeOut);
end;

Function SelectText(var T:Text;TimeOut :cint):cint;
var
  p  : PTimeVal;
  tv : TimeVal;
begin
  if TimeOut=-1 then
   p:=nil
  else
   begin
     tv.tv_Sec:=Timeout div 1000;
     tv.tv_Usec:=(Timeout mod 1000)*1000;
     p:=@tv;
   end;
  SelectText:=SelectText(T,p);
end;

{******************************************************************************
                               Directory
******************************************************************************}

procedure SeekDir(p:pdir;loc:clong);
begin
  if p=nil then
   begin
     fpseterrno(ESysEBADF);
     exit;
   end;
 {$if not(defined(bsd)) and not(defined(solaris)) }
  p^.dd_nextoff:=fplseek(p^.dd_fd,loc,seek_set);
 {$endif}
  p^.dd_size:=0;
  p^.dd_loc:=0;
end;

function TellDir(p:pdir):TOff;
begin
  if p=nil then
   begin
     fpseterrno(ESysEBADF);
     telldir:=-1;
     exit;
   end;
  telldir:=fplseek(p^.dd_fd,0,seek_cur)
  { We could try to use the nextoff field here, but on my 1.2.13
    kernel, this gives nothing... This may have to do with
    the readdir implementation of libc... I also didn't find any trace of
    the field in the kernel code itself, So I suspect it is an artifact of libc.
    Michael. }
end;

{******************************************************************************
                               Pipes/Fifo
******************************************************************************}

Procedure OpenPipe(var F:Text);
begin
  case textrec(f).mode of
    fmoutput :
      if textrec(f).userdata[1]<>P_OUT then
        textrec(f).mode:=fmclosed;
    fminput :
      if textrec(f).userdata[1]<>P_IN then
        textrec(f).mode:=fmclosed;
    else
      textrec(f).mode:=fmclosed;
  end;
end;

Function IOPipe(var F:text):cint;
begin
  IOPipe:=0;
  case textrec(f).mode of
    fmoutput :
      begin
        { first check if we need something to write, else we may
          get a SigPipe when Close() is called (PFV) }
        if textrec(f).bufpos>0 then
          IOPipe:=fpwrite(textrec(f).handle,pchar(textrec(f).bufptr),textrec(f).bufpos);
      end;
    fminput : Begin
                textrec(f).bufend:=fpread(textrec(f).handle,pchar(textrec(f).bufptr),textrec(f).bufsize);
                IOPipe:=textrec(f).bufend;
              End;
  end;
  textrec(f).bufpos:=0;
end;

Function FlushPipe(var F:Text):cint;
begin
  FlushPipe:=0;
  if (textrec(f).mode=fmoutput) and (textrec(f).bufpos<>0) then
   FlushPipe:=IOPipe(f);
  textrec(f).bufpos:=0;
end;

Function ClosePipe(var F:text):cint;
begin
  textrec(f).mode:=fmclosed;
  ClosePipe:=fpclose(textrec(f).handle);
end;


Function AssignPipe(var pipe_in,pipe_out:text):cint;
{
  Sets up a pair of file variables, which act as a pipe. The first one can
  be read from, the second one can be written to.
}
var
  f_in,f_out : cint;
begin
  if AssignPipe(f_in,f_out)=-1 then
     exit(-1);
{ Set up input }
  Assign(Pipe_in,'');
  Textrec(Pipe_in).Handle:=f_in;
  Textrec(Pipe_in).Mode:=fmInput;
  Textrec(Pipe_in).userdata[1]:=P_IN;
  TextRec(Pipe_in).OpenFunc:=@OpenPipe;
  TextRec(Pipe_in).InOutFunc:=@IOPipe;
  TextRec(Pipe_in).FlushFunc:=@FlushPipe;
  TextRec(Pipe_in).CloseFunc:=@ClosePipe;
{ Set up output }
  Assign(Pipe_out,'');
  Textrec(Pipe_out).Handle:=f_out;
  Textrec(Pipe_out).Mode:=fmOutput;
  Textrec(Pipe_out).userdata[1]:=P_OUT;
  TextRec(Pipe_out).OpenFunc:=@OpenPipe;
  TextRec(Pipe_out).InOutFunc:=@IOPipe;
  TextRec(Pipe_out).FlushFunc:=@FlushPipe;
  TextRec(Pipe_out).CloseFunc:=@ClosePipe;
  AssignPipe:=0;
end;

Function AssignPipe(var pipe_in,pipe_out:file):cint;
{
  Sets up a pair of file variables, which act as a pipe. The first one can
  be read from, the second one can be written to.
  If the operation was unsuccesful,
}
var
  f_in,f_out : cint;
begin
  if AssignPipe(f_in,f_out)=-1 then
     exit(-1);
{ Set up input }
  Assign(Pipe_in,'');
  Filerec(Pipe_in).Handle:=f_in;
  Filerec(Pipe_in).Mode:=fmInput;
  Filerec(Pipe_in).recsize:=1;
  Filerec(Pipe_in).userdata[1]:=P_IN;
{ Set up output }
  Assign(Pipe_out,'');
  Filerec(Pipe_out).Handle:=f_out;
  Filerec(Pipe_out).Mode:=fmoutput;
  Filerec(Pipe_out).recsize:=1;
  Filerec(Pipe_out).userdata[1]:=P_OUT;
  AssignPipe:=0;
end;


Function PCloseText(Var F:text):cint;
{
  May not use @PClose due overloading
}
begin
  PCloseText:=PClose(f);
end;


Function POpen(var F:text;const Prog:Ansistring;rw:char):cint;
{
  Starts the program in 'Prog' and makes it's input or out put the
  other end of a pipe. If rw is 'w' or 'W', then whatever is written to
  F, will be read from stdin by the program in 'Prog'. The inverse is true
  for 'r' or 'R' : whatever the program in 'Prog' writes to stdout, can be
  read from 'f'.
}
var
  pipi,
  pipo : text;
  pid  : cint;
  pl   : ^cint;
{$if not defined(FPC_USE_FPEXEC) or defined(USE_VFORK)}
  pp : array[0..3] of pchar;
  temp : string[255];
{$endif not FPC_USE_FPEXEC or USE_VFORK}
  ret  : cint;
begin
  rw:=upcase(rw);
  if not (rw in ['R','W']) then
   begin
     FpSetErrno(ESysEnoent);
     exit(-1);
   end;
  ret:=AssignPipe(pipi,pipo);
  if ret=-1 then
   exit(-1);
{$ifdef USE_VFORK}
  pid:=fpvfork;
{$else USE_VFORK}
  pid:=fpfork;
{$endif USE_VFORK}
  if pid=-1 then
   begin
     close(pipi);
     close(pipo);
     exit(-1);
   end;
  if pid=0 then
   begin
   { We're in the child }
     if rw='W' then
      begin
        if (textrec(pipi).handle <> stdinputhandle) then
          begin
            ret:=fpdup2(pipi,input);
{$ifdef USE_VFORK}
            fpclose(textrec(pipi).handle);
{$else USE_VFORK}
            close(pipi);
{$endif USE_VFORK}
          end;
{$ifdef USE_VFORK}
        fpclose(textrec(pipo).handle);
{$else USE_VFORK}
        close(pipo);
{$endif USE_VFORK}
        if ret=-1 then
         fpexit(127);
      end
     else
      begin
{$ifdef USE_VFORK}
        fpclose(textrec(pipi).handle);
{$else USE_VFORK}
        close(pipi);
{$endif USE_VFORK}
        if (textrec(pipo).handle <> stdoutputhandle) then
          begin
            ret:=fpdup2(pipo,output);
{$ifdef USE_VFORK}
            fpclose(textrec(pipo).handle);
{$else USE_VFORK}
            close(pipo);
{$endif USE_VFORK}
          end;
        if ret=-1 then
         fpexit(127);
      end;
     {$if defined(FPC_USE_FPEXEC) and not defined(USE_VFORK)}
     fpexecl(pchar('/bin/sh'),['-c',Prog]);
     {$else}
     temp:='/bin/sh'#0'-c'#0;
     pp[0]:=@temp[1];
     pp[1]:=@temp[9];
     pp[2]:=@prog[1];
     pp[3]:=Nil;
     fpExecve('/bin/sh',@pp,envp);
     {$endif}
     fpexit(127);
   end
  else
   begin
   { We're in the parent }
     if rw='W' then
      begin
        close(pipi);
        f:=pipo;
      end
     else
      begin
        close(pipo);
        f:=pipi;
      end;
     textrec(f).bufptr:=@textrec(f).buffer;
   {Save the process ID - needed when closing }
     pl:=pcint(@textrec(f).userdata[2]);
     { avoid alignment error on sparc }
     move(pid,pl^,sizeof(pid));
     textrec(f).closefunc:=@PCloseText;
   end;
 POpen:=0;
end;

Function POpen(var F:file;const Prog:Ansistring;rw:char):cint;
{
  Starts the program in 'Prog' and makes it's input or out put the
  other end of a pipe. If rw is 'w' or 'W', then whatever is written to
  F, will be read from stdin by the program in 'Prog'. The inverse is true
  for 'r' or 'R' : whatever the program in 'Prog' writes to stdout, can be
  read from 'f'.
}
var
  pipi,
  pipo : file;
  pid  : cint;
  pl   : ^cint;
{$if not defined(FPC_USE_FPEXEC) or defined(USE_VFORK)}
  pp : array[0..3] of pchar;
  temp : string[255];
{$endif not FPC_USE_FPEXEC or USE_VFORK}
  ret  : cint;
begin
  rw:=upcase(rw);
  if not (rw in ['R','W']) then
   begin
     FpSetErrno(ESysEnoent);
     exit(-1);
   end;
  ret:=AssignPipe(pipi,pipo);
  if ret=-1 then
   exit(-1);
{$ifdef USE_VFORK}
  pid:=fpvfork;
{$else USE_VFORK}
  pid:=fpfork;
{$endif USE_VFORK}
  if pid=-1 then
   begin
     close(pipi);
     close(pipo);
     exit(-1);
   end;
  if pid=0 then
   begin
   { We're in the child }
     if rw='W' then
      begin
        if (filerec(pipi).handle <> stdinputhandle) then
          begin
            ret:=fpdup2(filerec(pipi).handle,stdinputhandle);
{$ifdef USE_VFORK}
            fpclose(filerec(pipi).handle);
{$else USE_VFORK}
            close(pipi);
{$endif USE_VFORK}
          end;
{$ifdef USE_VFORK}
        fpclose(filerec(pipo).handle);
{$else USE_VFORK}
        close(pipo);
{$endif USE_VFORK}
        if ret=-1 then
         fpexit(127);
      end
     else
      begin
{$ifdef USE_VFORK}
        fpclose(filerec(pipi).handle);
{$else USE_VFORK}
        close(pipi);
{$endif USE_VFORK}
        if (filerec(pipo).handle <> stdoutputhandle) then
          begin
            ret:=fpdup2(filerec(pipo).handle,stdoutputhandle);
{$ifdef USE_VFORK}
            fpclose(filerec(pipo).handle);
{$else USE_VFORK}
            close(pipo);
{$endif USE_VFORK}
          end;
        if ret=-1 then
         fpexit(127);
      end;
     {$if defined(FPC_USE_FPEXEC) and not defined(USE_VFORK)}
     fpexecl(pchar('/bin/sh'),['-c',Prog]);
     {$else}
     temp:='/bin/sh'#0'-c'#0;
     pp[0]:=@temp[1];
     pp[1]:=@temp[9];
     pp[2]:=@prog[1];
     pp[3]:=Nil;
     fpExecve('/bin/sh',@pp,envp);
     {$endif}
     fpexit(127);
   end
  else
   begin
   { We're in the parent }
     if rw='W' then
      begin
        close(pipi);
        f:=pipo;
      end
     else
      begin
        close(pipo);
        f:=pipi;
      end;
   {Save the process ID - needed when closing }
     pl:=pcint(@filerec(f).userdata[2]);
     { avoid alignment error on sparc }
     move(pid,pl^,sizeof(pid));
   end;
 POpen:=0;
end;

Function AssignStream(Var StreamIn,Streamout:text;Const Prog:ansiString;const args : array of ansistring) : cint;
{
  Starts the program in 'Prog' and makes its input and output the
  other end of two pipes, which are the stdin and stdout of a program
  specified in 'Prog'.
  streamout can be used to write to the program, streamin can be used to read
  the output of the program. See the following diagram :
  Parent          Child
  STreamout -->  Input
  Streamin  <--  Output
  Return value is the process ID of the process being spawned, or -1 in case of failure.
}
var
  pipi,
  pipo : text;
  pid  : cint;
  pl   : ^cint;
begin
  AssignStream:=-1;
  if AssignPipe(streamin,pipo)=-1 Then
   exit(-1);
  if AssignPipe(pipi,streamout)=-1 Then
    begin
      close(streamin);
      close(pipo);
      exit(-1);
    end;
  pid:=fpfork;
  if pid=-1 then
   begin
     close(pipi);
     close(pipo);
     close (streamin);
     close (streamout);
     exit;
   end;
  if pid=0 then
   begin
     { We're in the child }
     { Close what we don't need }
     close(streamout);
     close(streamin);
     if fpdup2(pipi,input)=-1 Then
      halt(127);
     close(pipi);
     If fpdup2(pipo,output)=-1 Then
       halt (127);
     close(pipo);
     fpExecl(Prog,args);
     halt(127);
   end
  else
   begin
     { we're in the parent}
     close(pipo);
     close(pipi);
     {Save the process ID - needed when closing }
     pl:=pcint(@textrec(StreamIn).userdata[2]);
     { avoid alignment error on sparc }
     move(pid,pl^,sizeof(pid));
     textrec(StreamIn).closefunc:=@PCloseText;
     {Save the process ID - needed when closing }
     pl:=pcint(@textrec(StreamOut).userdata[2]);
     { avoid alignment error on sparc }
     move(pid,pl^,sizeof(pid));
     textrec(StreamOut).closefunc:=@PCloseText;
     AssignStream:=Pid;
   end;
end;

Function AssignStream(Var StreamIn,Streamout,streamerr:text;Const Prog:ansiString;const args : array of ansistring) : cint;

{
  Starts the program in 'prog' and makes its input, output and error output the
  other end of three pipes, which are the stdin, stdout and stderr of a program
  specified in 'prog'.
  StreamOut can be used to write to the program, StreamIn can be used to read
  the output of the program, StreamErr reads the error output of the program.
  See the following diagram :
  Parent          Child
  StreamOut -->  StdIn  (input)
  StreamIn  <--  StdOut (output)
  StreamErr <--  StdErr (error output)
}
var
  PipeIn, PipeOut, PipeErr: text;
  pid: cint;
  pl: ^cint;
begin
  AssignStream := -1;

  // Assign pipes
  if AssignPipe(StreamIn, PipeOut)=-1 Then
   Exit(-1);

  If AssignPipe(StreamErr, PipeErr)=-1 Then
  begin
    Close(StreamIn);
    Close(PipeOut);
    exit(-1);
  end;

  if AssignPipe(PipeIn, StreamOut)=-1 Then
  begin
    Close(StreamIn);
    Close(PipeOut);
    Close(StreamErr);
    Close(PipeErr);
    exit(-1);
  end;

  // Fork

  pid := fpFork;
  if pid=-1 then begin
    Close(StreamIn);
    Close(PipeOut);
    Close(StreamErr);
    Close(PipeErr);
    Close(PipeIn);
    Close(StreamOut);
    exit(-1);
  end;

  if pid = 0 then begin
    // *** We are in the child ***
    // Close what we don not need
    Close(StreamOut);
    Close(StreamIn);
    Close(StreamErr);
    // Connect pipes
    if fpdup2(PipeIn, Input)=-1 Then
     Halt(127);
    Close(PipeIn);
    if fpdup2(PipeOut, Output)=-1 Then
     Halt(127);
    Close(PipeOut);
    if fpdup2(PipeErr, StdErr)=-1 Then
     Halt(127);
    Close(PipeErr);
    // Execute program
    fpExecl(Prog,args);
    Halt(127);
  end else begin
    // *** We are in the parent ***
    Close(PipeErr);
    Close(PipeOut);
    Close(PipeIn);
    // Save the process ID - needed when closing
    pl := pcint(@TextRec(StreamIn).userdata[2]);
    { avoid alignment error on sparc }
    move(pid,pl^,sizeof(pid));
    TextRec(StreamIn).closefunc := @PCloseText;
    // Save the process ID - needed when closing
    pl := pcint(@TextRec(StreamOut).userdata[2]);
    { avoid alignment error on sparc }
    move(pid,pl^,sizeof(pid));
    TextRec(StreamOut).closefunc := @PCloseText;
    // Save the process ID - needed when closing
    pl := pcint(@TextRec(StreamErr).userdata[2]);
    { avoid alignment error on sparc }
    move(pid,pl^,sizeof(pid));
    TextRec(StreamErr).closefunc := @PCloseText;
    AssignStream := pid;
  end;
end;

{******************************************************************************
                        General information calls
******************************************************************************}

{$ifdef Linux}
Function GetDomainName:String;  { linux only!}
// domainname is a glibc extension.

{
  Get machines domain name. Returns empty string if not set.
}
Var
  Sysn : utsname;
begin
  If fpUname(sysn)<>0 then
   getdomainname:=''
  else
   getdomainname:=strpas(@Sysn.domain[0]);
end;
{$endif}

{$ifdef sunos}
{ sunos doesn't support GetDomainName, see also
  http://www.sun.com/software/solaris/programs/abi/appcert_faq.xml#q18
}
Function GetDomainName:String;
  begin
    GetDomainName:='';
  end;
{$endif sunos}

{$ifdef BSD}

function intGetDomainName(Name:PChar; NameLen:Cint):cint;
{$ifndef FPC_USE_LIBC}
 external name 'FPC_SYSC_GETDOMAINNAME';
{$else FPC_USE_LIBC}
 cdecl; external clib name 'getdomainname';
{$endif FPC_USE_LIBC}

Function GetDomainName:String;  { linux only!}
// domainname is a glibc extension.

{
  Get machines domain name. Returns empty string if not set.
}

begin
  if intGetDomainName(@getdomainname[1],255)=-1 then
   getdomainname:=''
  else
   getdomainname[0]:=chr(strlen(@getdomainname[1]));
end;
{$endif}


Function GetHostName:String;
{
  Get machines name. Returns empty string if not set.
}
Var
  Sysn : utsname;
begin
  If fpuname(sysn)=-1 then
   gethostname:=''
  else
   gethostname:=strpas(@Sysn.nodename[0]);
end;

{******************************************************************************
                          Signal handling calls
******************************************************************************}

procedure SigRaise(sig:integer);
begin
  fpKill(fpGetPid,Sig);
end;


{******************************************************************************
                             Utility calls
******************************************************************************}

Function FSearch(const path:AnsiString;dirlist:Ansistring;CurrentDirStrategy:TFSearchOption):AnsiString;
{
  Searches for a file 'path' in the list of direcories in 'dirlist'.
  returns an empty string if not found. Wildcards are NOT allowed.
  If dirlist is empty, it is set to '.'

This function tries to make FSearch use ansistrings, and decrease
stringhandling overhead at the same time.

}
Var
  mydir,NewDir : ansistring;
  p1     : cint;
  Info   : Stat;
  i,j      : cint;
  p      : pchar;
Begin

 if CurrentDirStrategy=CurrentDirectoryFirst Then
     Dirlist:='.:'+dirlist;             {Make sure current dir is first to be searched.}
 if CurrentDirStrategy=CurrentDirectoryLast Then
     Dirlist:=dirlist+':.';             {Make sure current dir is last to be searched.}

{Replace ':' and ';' with #0}

 for p1:=1 to length(dirlist) do
   if (dirlist[p1]=':') or (dirlist[p1]=';') then
    dirlist[p1]:=#0;

{Check for WildCards}
  If (Pos('?',Path) <> 0) or (Pos('*',Path) <> 0) Then
   FSearch:='' {No wildcards allowed in these things.}
  Else
   Begin
     p:=pchar(dirlist);
     i:=length(dirlist);
     j:=1;
     Repeat
       mydir:=ansistring(p);
       if (length(mydir)>0) and (mydir[length(mydir)]<>'/') then
          mydir:=mydir+'/';
       NewDir:=mydir+Path;
       if (FpStat(NewDir,Info)>=0) and
          (not fpS_ISDIR(Info.st_Mode)) then
        Begin
          If Pos('./',NewDir)=1 Then
           Delete(NewDir,1,2);
        {DOS strips off an initial .\}
        End
       Else
        NewDir:='';
       while (j<=i) and (p^<>#0) do begin inc(j); inc(p); end;
       if p^=#0 then inc(p);
     Until (j>=i) or (Length(NewDir) > 0);
     FSearch:=NewDir;
   End;
End;

Function FSearch(const path:AnsiString;dirlist:Ansistring):AnsiString;

Begin
 FSearch:=FSearch(path,dirlist,CurrentDirectoryFirst);
End;

{--------------------------------
      Stat.Mode Macro's
--------------------------------}

Initialization
{$IFNDEF DONT_READ_TIMEZONE}
  InitLocalTime;
{$endif}
finalization
{$IFNDEF DONT_READ_TIMEZONE}
  DoneLocalTime;
{$endif}
End.