utils/wvsystem.cc

   1 /*
   2  * Worldvisions Weaver Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  *
   5  * A more convenient wrapper around WvSubProc.  See wvsystem.h.
   6  */
   7 #include "wvsystem.h"
   8 #include <unistd.h>
   9 #include <fcntl.h>
  10 #include <sys/types.h>
  11
  12 WvSystem::~WvSystem()
  13 {
  14     go();
  15 }
  16
  17
  18 void WvSystem::init(const char * const *argv)
  19 {
  20     started = false;
  21     WvSubProc::preparev(argv[0], argv);
  22 }
  23
  24
  25 // open a given filename or device, making sure it has the given fd.  If
  26 // there is an open file on that fd already, it gets closed.
  27 static void fd_open(int fd, WvStringParm file, int mode)
  28 {
  29     ::close(fd);
  30     int nfd = ::open(file, mode, 0666);
  31     if (nfd < 0)
  32         return;
  33     if (nfd != fd)
  34     {
  35         ::dup2(nfd, fd);
  36         ::close(nfd);
  37     }
  38 }
  39
  40
  41 // overrides WvSubProc::fork().
  42 int WvSystem::fork(int *waitfd)
  43 {
  44     int pid = WvSubProc::fork(waitfd);
  45     if (!pid) // child
  46     {
  47         if (!fdfiles[0].isnull())
  48             fd_open(0, fdfiles[0], O_RDONLY);
  49         if (!fdfiles[1].isnull())
  50             fd_open(1, fdfiles[1], O_WRONLY|O_CREAT);
  51         if (!fdfiles[2].isnull())
  52             fd_open(2, fdfiles[2], O_WRONLY|O_CREAT);
  53     }
  54
  55     return pid;
  56 }
  57
  58
  59 int WvSystem::go()
  60 {
  61     if (!started)
  62     {
  63         WvSubProc::start_again();
  64         started = true;
  65     }
  66     WvSubProc::wait(-1, false);
  67     return WvSubProc::estatus;
  68 }
  69
  70
  71 WvSystem &WvSystem::infile(WvStringParm filename)
  72 {
  73     fdfiles[0] = filename;
  74     return *this;
  75 }
  76
  77
  78 WvSystem &WvSystem::outfile(WvStringParm filename)
  79 {
  80     fdfiles[1] = filename;
  81     return *this;
  82 }
  83
  84
  85 WvSystem &WvSystem::errfile(WvStringParm filename)
  86 {
  87     fdfiles[2] = filename;
  88     return *this;
  89 }
  90
  91