summaryrefslogtreecommitdiff
path: root/qtermwidget/k3process.h
blob: f8388eac34cd5fa118a7f94f3f6a7a3f6408a23e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
/* This file is part of the KDE libraries
    Copyright (C) 1997 Christian Czezakte (e9025461@student.tuwien.ac.at)

    Rewritten for QT4 by e_k <e_k at users.sourceforge.net>, Copyright (C)2008

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library 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.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
*/

#ifndef K3PROCESS_H
#define K3PROCESS_H

#include <QtCore/QObject>

#include <sys/types.h> // for pid_t
#include <sys/wait.h>
#include <signal.h>
#include <unistd.h>

class QSocketNotifier;
class K3ProcessPrivate;
class KPty;

/**
 * @obsolete Use KProcess and KPtyProcess instead.
 *
 * Child process invocation, monitoring and control.
 * This class works only in the application's main thread.
 *
 * <b>General usage and features:</b>\n
 *
 * This class allows a KDE application to start child processes without having
 * to worry about UN*X signal handling issues and zombie process reaping.
 *
 * @see K3ProcIO
 *
 * Basically, this class distinguishes three different ways of running
 * child processes:
 *
 * @li  DontCare -- The child process is invoked and both the child
 * process and the parent process continue concurrently.
 *
 * The process is started in an own session (see setsid(2)).
 *
 * @li  NotifyOnExit -- The child process is invoked and both the
 * child and the parent process run concurrently.
 *
 * When the child process exits, the K3Process instance
 * corresponding to it emits the Qt signal processExited().
 * Since this signal is @em not emitted from within a UN*X
 * signal handler, arbitrary function calls can be made.
 *
 * Be aware: When the K3Process object gets destructed, the child
 * process will be killed if it is still running!
 * This means in particular, that it usually makes no sense to use
 * a K3Process on the stack with NotifyOnExit.
 *
 * @li  OwnGroup -- like NotifyOnExit, but the child process is started
 * in an own process group (and an own session, FWIW). The behavior of
 * kill() changes to killing the whole process group - this makes
 * this mode useful for implementing primitive job management. It can be
 * used to work around broken wrapper scripts that don't propagate signals
 * to the "real" program. However, use this with care, as you disturb the
 * shell's job management if your program is started from the command line.
 *
 * @li  Block -- The child process starts and the parent process
 * is suspended until the child process exits. (@em Really not recommended
 * for programs with a GUI.)
 * In this mode the parent can read the child's output, but can't send it any
 * input.
 *
 * K3Process also provides several functions for determining the exit status
 * and the pid of the child process it represents.
 *
 * Furthermore it is possible to supply command-line arguments to the process
 * in a clean fashion (no null-terminated stringlists and such...)
 *
 * A small usage example:
 * \code
 *   K3Process *proc = new K3Process;
 *
 *   *proc << "my_executable";
 *   *proc << "These" << "are" << "the" << "command" << "line" << "args";
 *   QApplication::connect(proc, SIGNAL(processExited(K3Process *)),
 *                         pointer_to_my_object, SLOT(my_objects_slot(K3Process *)));
 *   proc->start();
 * \endcode
 *
 * This will start "my_executable" with the commandline arguments "These"...
 *
 * When the child process exits, the slot will be invoked.
 *
 * <b>Communication with the child process:</b>\n
 *
 * K3Process supports communication with the child process through
 * stdin/stdout/stderr.
 *
 * The following functions are provided for getting data from the child
 * process or sending data to the child's stdin (For more information,
 * have a look at the documentation of each function):
 *
 * @li writeStdin()
 *  -- Transmit data to the child process' stdin. When all data was sent, the
 * signal wroteStdin() is emitted.
 *
 * @li When data arrives at stdout or stderr, the signal receivedStdout()
 * resp. receivedStderr() is emitted.
 *
 * @li You can shut down individual communication channels with
 * closeStdin(), closeStdout(), and closeStderr(), resp.
 *
 * @author Christian Czezatke e9025461@student.tuwien.ac.at
 *
 **/
class K3Process : public QObject
{
  Q_OBJECT

public:

  /**
   * Modes in which the communication channels can be opened.
   *
   * If communication for more than one channel is required,
   * the values should be or'ed together, for example to get
   * communication with stdout as well as with stdin, you would
   * specify @p Stdin | @p Stdout
   *
   */
  enum CommunicationFlag {
       NoCommunication = 0, /**< No communication with the process. */
       Stdin = 1, /**< Connect to write to the process with writeStdin(). */
       Stdout = 2, /**< Connect to read from the process' output. */
       Stderr = 4, /**< Connect to read from the process' stderr. */
       AllOutput = 6, /**< Connects to all output channels. */
       All = 7, /**< Connects to all channels. */
       NoRead = 8, /**< If specified with Stdout, no data is actually read from stdout,
                    * only the signal receivedStdout(int fd, int &len) is emitted. */
       CTtyOnly = NoRead, /**< Tells setUsePty() to create a PTY for the process
                           * and make it the process' controlling TTY, but does not
                           * redirect any I/O channel to the PTY. */
       MergedStderr = 16  /**< If specified with Stdout, the process' stderr will be
                           * redirected onto the same file handle as its stdout, i.e.,
                           * all error output will be signalled with receivedStdout().
                           * Don't specify Stderr if you specify MergedStderr. */
  };

  Q_DECLARE_FLAGS(Communication, CommunicationFlag)

  /**
   * Run-modes for a child process.
   */
  enum RunMode {
      /**
       * The application does not receive notifications from the subprocess when
       * it is finished or aborted.
       */
       DontCare,
       /**
        * The application is notified when the subprocess dies.
        */
       NotifyOnExit,
       /**
        * The application is suspended until the started process is finished.
        */
       Block,
       /**
        * Same as NotifyOnExit, but the process is run in an own session,
        * just like with DontCare.
        */
       OwnGroup
  };

  /**
   * Constructor
   */
  explicit K3Process( QObject* parent=0L );

  /**
   *Destructor:
   *
   *  If the process is running when the destructor for this class
   *  is called, the child process is killed with a SIGKILL, but
   *  only if the run mode is not of type @p DontCare.
   *  Processes started as @p DontCare keep running anyway.
  */
  virtual ~K3Process();

  /**
   * Sets the executable and the command line argument list for this process.
   *
   * For example, doing an "ls -l /usr/local/bin" can be achieved by:
   *  \code
   *  K3Process p;
   *  ...
   *  p << "ls" << "-l" << "/usr/local/bin"
   *  \endcode
   *
   * @param arg the argument to add
   * @return a reference to this K3Process
   **/
  K3Process &operator<<(const QString& arg);
  /**
   * Similar to previous method, takes a char *, supposed to be in locale 8 bit already.
   */
  K3Process &operator<<(const char * arg);
  /**
   * Similar to previous method, takes a QByteArray, supposed to be in locale 8 bit already.
   * @param arg the argument to add
   * @return a reference to this K3Process
   */
  K3Process &operator<<(const QByteArray & arg);

  /**
   * Sets the executable and the command line argument list for this process,
   * in a single method call, or add a list of arguments.
   * @param args the arguments to add
   * @return a reference to this K3Process
   **/
  K3Process &operator<<(const QStringList& args);

  /**
   * Clear a command line argument list that has been set by using
   * operator<<.
  */
  void clearArguments();

  /**
   *  Starts the process.
   *  For a detailed description of the
   *  various run modes and communication semantics, have a look at the
   *  general description of the K3Process class. Note that if you use
   * setUsePty( Stdout | Stderr, \<bool\> ), you cannot use Stdout | Stderr
   *  here - instead, use Stdout only to receive the mixed output.
   *
   *  The following problems could cause this function to
   *    return false:
   *
   *  @li The process is already running.
   *  @li The command line argument list is empty.
   *  @li The the @p comm parameter is incompatible with the selected pty usage.
   *  @li The starting of the process failed (could not fork).
   *  @li The executable was not found.
   *
   *  @param runmode The Run-mode for the process.
   *  @param comm  Specifies which communication channels should be
   *  established to the child process (stdin/stdout/stderr). By default,
   *  no communication takes place and the respective communication
   *  signals will never get emitted.
   *
   *  @return true on success, false on error
   *  (see above for error conditions)
   **/
  virtual bool start(RunMode  runmode = NotifyOnExit,
                     Communication comm = NoCommunication);

  /**
   * Stop the process (by sending it a signal).
   *
   * @param signo The signal to send. The default is SIGTERM.
   * @return true if the signal was delivered successfully.
  */
  virtual bool kill(int signo = SIGTERM);

  /**
   * Checks whether the process is running.
   * @return true if the process is (still) considered to be running
  */
  bool isRunning() const;

  /** Returns the process id of the process.
   *
   * If it is called after
   * the process has exited, it returns the process id of the last
   *  child process that was created by this instance of K3Process.
   *
   *  Calling it before any child process has been started by this
   *  K3Process instance causes pid() to return 0.
   * @return the pid of the process or 0 if no process has been started yet.
   **/
  pid_t pid() const;

  /**
   * Suspend processing of data from stdout of the child process.
   */
  void suspend();

  /**
   * Resume processing of data from stdout of the child process.
   */
  void resume();

  /**
   * Suspend execution of the current thread until the child process dies
   * or the timeout hits. This function is not recommended for programs
   * with a GUI.
   * @param timeout timeout in seconds. -1 means wait indefinitely.
   * @return true if the process exited, false if the timeout hit.
   */
  bool wait(int timeout = -1);

  /**
   * Checks whether the process exited cleanly.
   *
   * @return true if the process has already finished and has exited
   *  "voluntarily", ie: it has not been killed by a signal.
   */
  bool normalExit() const;

  /**
   * Checks whether the process was killed by a signal.
   *
   * @return true if the process has already finished and has not exited
   * "voluntarily", ie: it has been killed by a signal.
   */
  bool signalled() const;

  /**
   * Checks whether a killed process dumped core.
   *
   * @return true if signalled() returns true and the process
   * dumped core. Note that on systems that don't define the
   * WCOREDUMP macro, the return value is always false.
   */
  bool coreDumped() const;

  /**
   * Returns the exit status of the process.
   *
   * @return the exit status of the process. Note that this value
   * is not valid if normalExit() returns false.
   */
  int exitStatus() const;

  /**
   * Returns the signal the process was killed by.
   *
   * @return the signal number that caused the process to exit.
   * Note that this value is not valid if signalled() returns false.
   */
  int exitSignal() const;

  /**
   *	 Transmit data to the child process' stdin.
   *
   * This function may return false in the following cases:
   *
   *     @li The process is not currently running.
   * This implies that you cannot use this function in Block mode.
   *
   *     @li Communication to stdin has not been requested in the start() call.
   *
   *     @li Transmission of data to the child process by a previous call to
   * writeStdin() is still in progress.
   *
   * Please note that the data is sent to the client asynchronously,
   * so when this function returns, the data might not have been
   * processed by the child process.
   * That means that you must not free @p buffer or call writeStdin()
   * again until either a wroteStdin() signal indicates that the
   * data has been sent or a processExited() signal shows that
   * the child process is no longer alive.
   *
   * If all the data has been sent to the client, the signal
   * wroteStdin() will be emitted.
   *
   * This function does not work when the process is start()ed in Block mode.
   *
   * @param buffer the buffer to write
   * @param buflen the length of the buffer
   * @return false if an error has occurred
   **/
  bool writeStdin(const char *buffer, int buflen);

  /**
   * Shuts down the Stdin communication link. If no pty is used, this
   * causes "EOF" to be indicated on the child's stdin file descriptor.
   *
   * @return false if no Stdin communication link exists (any more).
   */
  bool closeStdin();

  /**
   * Shuts down the Stdout communication link. If no pty is used, any further
   * attempts by the child to write to its stdout file descriptor will cause
   * it to receive a SIGPIPE.
   *
   * @return false if no Stdout communication link exists (any more).
   */
  bool closeStdout();

  /**
   * Shuts down the Stderr communication link. If no pty is used, any further
   * attempts by the child to write to its stderr file descriptor will cause
   * it to receive a SIGPIPE.
   *
   * @return false if no Stderr communication link exists (any more).
   */
  bool closeStderr();

  /**
   * Deletes the optional utmp entry and closes the pty.
   *
   * Make sure to shut down any communication links that are using the pty
   * before calling this function.
   *
   * @return false if the pty is not open (any more).
   */
  bool closePty();

  /**
   * @brief Close stdin, stdout, stderr and the pty
   *
   * This is the same that calling all close* functions in a row:
   * @see closeStdin, @see closeStdout, @see closeStderr and @see closePty
   */
  void closeAll();

  /**
   * Lets you see what your arguments are for debugging.
   * @return the list of arguments
   */
  const QList<QByteArray> &args() /* const */ { return arguments; }

  /**
   * Controls whether the started process should drop any
   * setuid/setgid privileges or whether it should keep them.
   * Note that this function is mostly a dummy, as the KDE libraries
   * currently refuse to run with setuid/setgid privileges.
   *
   * The default is false: drop privileges
   * @param keepPrivileges true to keep the privileges
   */
  void setRunPrivileged(bool keepPrivileges);

  /**
   * Returns whether the started process will drop any
   * setuid/setgid privileges or whether it will keep them.
   * @return true if the process runs privileged
   */
  bool runPrivileged() const;

  /**
   * Adds the variable @p name to the process' environment.
   * This function must be called before starting the process.
   * @param name the name of the environment variable
   * @param value the new value for the environment variable
   */
  void setEnvironment(const QString &name, const QString &value);

  /**
   * Changes the current working directory (CWD) of the process
   * to be started.
   * This function must be called before starting the process.
   * @param dir the new directory
   */
  void setWorkingDirectory(const QString &dir);

  /**
   * Specify whether to start the command via a shell or directly.
   * The default is to start the command directly.
   * If @p useShell is true @p shell will be used as shell, or
   * if shell is empty, /bin/sh will be used.
   *
   * When using a shell, the caller should make sure that all filenames etc.
   * are properly quoted when passed as argument.
   * @see quote()
   * @param useShell true if the command should be started via a shell
   * @param shell the path to the shell that will execute the process, or
   *              0 to use /bin/sh. Use getenv("SHELL") to use the user's
   *              default shell, but note that doing so is usually a bad idea
   *              for shell compatibility reasons.
   */
  void setUseShell(bool useShell, const char *shell = 0);

  /**
   * This function can be used to quote an argument string such that
   * the shell processes it properly. This is e. g. necessary for
   * user-provided file names which may contain spaces or quotes.
   * It also prevents expansion of wild cards and environment variables.
   * @param arg the argument to quote
   * @return the quoted argument
   */
  static QString quote(const QString &arg);

  /**
   * Detaches K3Process from child process. All communication is closed.
   * No exit notification is emitted any more for the child process.
   * Deleting the K3Process will no longer kill the child process.
   * Note that the current process remains the parent process of the
   * child process.
   */
  void detach();

  /**
   * Specify whether to create a pty (pseudo-terminal) for running the
   * command.
   * This function should be called before starting the process.
   *
   * @param comm for which stdio handles to use a pty. Note that it is not
   *  allowed to specify Stdout and Stderr at the same time both here and to
   * start (there is only one pty, so they cannot be distinguished).
   * @param addUtmp true if a utmp entry should be created for the pty
   */
  void setUsePty(Communication comm, bool addUtmp);

  /**
   * Obtains the pty object used by this process. The return value is
   * valid only after setUsePty() was used with a non-zero argument.
   * The pty is open only while the process is running.
   * @return a pointer to the pty object
   */
  KPty *pty() const;

  /**
   * More or less intuitive constants for use with setPriority().
   */
  enum { PrioLowest = 20, PrioLow = 10, PrioLower = 5, PrioNormal = 0,
    PrioHigher = -5, PrioHigh = -10, PrioHighest = -19 };

  /**
   * Sets the scheduling priority of the process.
   * @param prio the new priority in the range -20 (high) to 19 (low).
   * @return false on error; see setpriority(2) for possible reasons.
   */
  bool setPriority(int prio);

Q_SIGNALS:
  /**
   * Emitted after the process has terminated when
   * the process was run in the @p NotifyOnExit  (==default option to
   * start() ) or the Block mode.
   * @param proc a pointer to the process that has exited
   **/
  void processExited(K3Process *proc);


  /**
   * Emitted, when output from the child process has
   * been received on stdout.
   *
   * To actually get this signal, the Stdout communication link
   * has to be turned on in start().
   *
   * @param proc a pointer to the process that has received the output
   * @param buffer The data received.
   * @param buflen The number of bytes that are available.
   *
   * You should copy the information contained in @p buffer to your private
   * data structures before returning from the slot.
   * Example:
   * \code
   *     QString myBuf = QLatin1String(buffer, buflen);
   * \endcode
   **/
  void receivedStdout(K3Process *proc, char *buffer, int buflen);

  /**
   * Emitted when output from the child process has
   * been received on stdout.
   *
   * To actually get this signal, the Stdout communication link
   * has to be turned on in start() and the
   * NoRead flag must have been passed.
   *
   * You will need to explicitly call resume() after your call to start()
   * to begin processing data from the child process' stdout.  This is
   * to ensure that this signal is not emitted when no one is connected
   * to it, otherwise this signal will not be emitted.
   *
   * The data still has to be read from file descriptor @p fd.
   * @param fd the file descriptor that provides the data
   * @param len the number of bytes that have been read from @p fd must
   *  be written here
   **/
  void receivedStdout(int fd, int &len); // KDE4: change, broken API


  /**
   * Emitted, when output from the child process has
   * been received on stderr.
   *
   * To actually get this signal, the Stderr communication link
   * has to be turned on in start().
   *
   * You should copy the information contained in @p buffer to your private
   * data structures before returning from the slot.
   *
   * @param proc a pointer to the process that has received the data
   * @param buffer The data received.
   * @param buflen The number of bytes that are available.
   **/
  void receivedStderr(K3Process *proc, char *buffer, int buflen);

  /**
   * Emitted after all the data that has been
   * specified by a prior call to writeStdin() has actually been
   * written to the child process.
   * @param proc a pointer to the process
   **/
  void wroteStdin(K3Process *proc);


protected Q_SLOTS:

 /**
  * This slot gets activated when data from the child's stdout arrives.
  * It usually calls childOutput().
  * @param fdno the file descriptor for the output
  */
  void slotChildOutput(int fdno);

 /**
  * This slot gets activated when data from the child's stderr arrives.
  * It usually calls childError().
  * @param fdno the file descriptor for the output
  */
  void slotChildError(int fdno);

  /**
   * Called when another bulk of data can be sent to the child's
   * stdin. If there is no more data to be sent to stdin currently
   * available, this function must disable the QSocketNotifier innot.
   * @param dummy ignore this argument
   */
  void slotSendData(int dummy);	// KDE 4: remove dummy

protected:

  /**
   * Sets up the environment according to the data passed via
   * setEnvironment()
   */
  void setupEnvironment();

  /**
   * The list of the process' command line arguments. The first entry
   * in this list is the executable itself.
   */
  QList<QByteArray> arguments;
  /**
   * How to run the process (Block, NotifyOnExit, DontCare). You should
   *  not modify this data member directly from derived classes.
   */
  RunMode run_mode;
  /**
   * true if the process is currently running. You should not
   * modify this data member directly from derived classes. Please use
   * isRunning() for reading the value of this data member since it
   * will probably be made private in later versions of K3Process.
   */
  bool runs;

  /**
   * The PID of the currently running process.
   * You should not modify this data member in derived classes.
   * Please use pid() instead of directly accessing this
   * member since it will probably be made private in
   * later versions of K3Process.
   */
  pid_t pid_;

  /**
   * The process' exit status as returned by waitpid(). You should not
   * modify the value of this data member from derived classes. You should
   * rather use exitStatus() than accessing this data member directly
   * since it will probably be made private in further versions of
   * K3Process.
   */
  int status;


  /**
   * If false, the child process' effective uid & gid will be reset to the
   * real values.
   * @see setRunPrivileged()
   */
  bool keepPrivs;

  /**
   * This function is called from start() right before a fork() takes
   * place. According to the @p comm parameter this function has to initialize
   * the in, out and err data members of K3Process.
   *
   * This function should return 1 if setting the needed communication channels
   * was successful.
   *
   * The default implementation is to create UNIX STREAM sockets for the
   * communication, but you could reimplement this function to establish a
   * TCP/IP communication for network communication, for example.
   */
  virtual int setupCommunication(Communication comm);

  /**
   * Called right after a (successful) fork() on the parent side. This function
   * will usually do some communications cleanup, like closing in[0],
   * out[1] and out[1].
   *
   * Furthermore, it must also create the QSocketNotifiers innot,
   * outnot and errnot and connect their Qt signals to the respective
   * K3Process slots.
   *
   * For a more detailed explanation, it is best to have a look at the default
   * implementation in kprocess.cpp.
   */
  virtual int commSetupDoneP();

  /**
   * Called right after a (successful) fork(), but before an exec() on the child
   * process' side. It usually duplicates the in[0], out[1] and
   * err[1] file handles to the respective standard I/O handles.
   */
  virtual int commSetupDoneC();


  /**
   * Immediately called after a successfully started process in NotifyOnExit
   * mode has exited. This function normally calls commClose()
   * and emits the processExited() signal.
   * @param state the exit code of the process as returned by waitpid()
   */
  virtual void processHasExited(int state);

  /**
   * Cleans up the communication links to the child after it has exited.
   * This function should act upon the values of pid() and runs.
   * See the kprocess.cpp source for details.
   * @li If pid() returns zero, the communication links should be closed
   *  only.
   * @li if pid() returns non-zero and runs is false, all data
   *  immediately available from the communication links should be processed
   *  before closing them.
   * @li if pid() returns non-zero and runs is true, the communication
   *  links should be monitored for data until the file handle returned by
   *  K3ProcessController::theKProcessController->notifierFd() becomes ready
   *  for reading - when it triggers, runs should be reset to false, and
   *  the function should be immediately left without closing anything.
   *
   * The previous semantics of this function are forward-compatible, but should
   * be avoided, as they are prone to race conditions and can cause K3Process
   * (and thus the whole program) to lock up under certain circumstances. At the
   * end the function closes the communication links in any case. Additionally
   * @li if runs is true, the communication links are monitored for data
   *  until all of them have returned EOF. Note that if any system function is
   *  interrupted (errno == EINTR) the polling loop should be aborted.
   * @li if runs is false, all data immediately available from the
   *  communication links is processed.
   */
  virtual void commClose();

  /* KDE 4 - commClose will be changed to perform cleanup only in all cases *
   * If @p notfd is -1, all data immediately available from the
   *  communication links should be processed.
   * If @p notfd is not -1, the communication links should be monitored
   *  for data until the file handle @p notfd becomes ready for reading.
   */
//  virtual void commDrain(int notfd);

  /**
   * Specify the actual executable that should be started (first argument to execve)
   * Normally the the first argument is the executable but you can
   * override that with this function.
   */
  void setBinaryExecutable(const char *filename);

  /**
   * The socket descriptors for stdout.
   */
  int out[2];
  /**
   * The socket descriptors for stdin.
   */
  int in[2];
  /**
   * The socket descriptors for stderr.
   */
  int err[2];

  /**
   * The socket notifier for in[1].
   */
  QSocketNotifier *innot;
  /**
   * The socket notifier for out[0].
   */
  QSocketNotifier *outnot;
  /**
   * The socket notifier for err[0].
   */
  QSocketNotifier *errnot;

  /**
   * Lists the communication links that are activated for the child
   * process.  Should not be modified from derived classes.
   */
  Communication communication;

  /**
   * Called by slotChildOutput() this function copies data arriving from
   * the child process' stdout to the respective buffer and emits the signal
   * receivedStdout().
   */
  int childOutput(int fdno);

  /**
   * Called by slotChildError() this function copies data arriving from
   * the child process' stderr to the respective buffer and emits the signal
   * receivedStderr().
   */
  int childError(int fdno);

  /**
   * The buffer holding the data that has to be sent to the child
   */
  const char *input_data;
  /**
   * The number of bytes already transmitted
   */
  int input_sent;
  /**
   * The total length of input_data
   */
  int input_total;

  /**
   * K3ProcessController is a friend of K3Process because it has to have
   * access to various data members.
   */
  friend class K3ProcessController;

private:
  K3ProcessPrivate* const d;
};

Q_DECLARE_OPERATORS_FOR_FLAGS(K3Process::Communication)

class K3ShellProcessPrivate;

/**
* @obsolete
*
* Use K3Process and K3Process::setUseShell(true) instead.
*
*   @short A class derived from K3Process to start child
*   	processes through a shell.
*   @author Christian Czezatke <e9025461@student.tuwien.ac.at>
*/
class K3ShellProcess : public K3Process
{
  Q_OBJECT

public:

  /**
   * Constructor
   *
   * If no shellname is specified, the user's default shell is used.
   */
  explicit K3ShellProcess(const char *shellname=0);

  /**
   * Destructor.
   */
  ~K3ShellProcess();

  virtual bool start(RunMode  runmode = NotifyOnExit,
		  Communication comm = NoCommunication);

  static QString quote(const QString &arg);

private:
  K3ShellProcessPrivate* const d;
};



#endif