File: sem.c

package info (click to toggle)
csh 20110502-2
  • links: PTS
  • area: main
  • in suites: wheezy
  • size: 1,104 kB
  • sloc: ansic: 11,984; makefile: 62; sh: 16
file content (627 lines) | stat: -rw-r--r-- 16,125 bytes parent folder | download | duplicates (5)
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
/*	$OpenBSD: sem.c,v 1.17 2010/08/12 02:00:27 kevlo Exp $	*/
/*	$NetBSD: sem.c,v 1.9 1995/09/27 00:38:50 jtc Exp $	*/

/*-
 * Copyright (c) 1980, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <bsd/string.h>
#include <unistd.h>
#include <stdarg.h>

#include "csh.h"
#include "proc.h"
#include "extern.h"

static void	 vffree(int);
static Char	*splicepipe(struct command *t, Char *);
static void	 doio(struct command *t, int *, int *);
static void	 chkclob(char *);

void
execute(struct command *t, int wanttty, int *pipein, int *pipeout)
{
    bool    forked = 0;
    struct biltins *bifunc;
    int     pid = 0;
    int     pv[2];
    sigset_t sigset;

    static sigset_t csigset;

    static sigset_t ocsigset;
    static int onosigchld = 0;
    static int nosigchld = 0;

    UNREGISTER(forked);
    UNREGISTER(bifunc);
    UNREGISTER(wanttty);

    if (t == 0)
	return;

    if (t->t_dflg & F_AMPERSAND)
	wanttty = 0;
    switch (t->t_dtyp) {

    case NODE_COMMAND:
	if ((t->t_dcom[0][0] & (QUOTE | TRIM)) == QUOTE)
	    (void) memmove(t->t_dcom[0], t->t_dcom[0] + 1,
		(Strlen(t->t_dcom[0] + 1) + 1) * sizeof(Char));
	if ((t->t_dflg & F_REPEAT) == 0)
	    Dfix(t);		/* $ " ' \ */
	if (t->t_dcom[0] == 0)
	    return;
	/* fall into... */

    case NODE_PAREN:
	if (t->t_dflg & F_PIPEOUT)
	    mypipe(pipeout);
	/*
	 * Must do << early so parent will know where input pointer should be.
	 * If noexec then this is all we do.
	 */
	if (t->t_dflg & F_READ) {
	    (void) close(0);
	    heredoc(t->t_dlef);
	    if (noexec)
		(void) close(0);
	}

	set(STRstatus, Strsave(STR0));

	/*
	 * This mess is the necessary kludge to handle the prefix builtins:
	 * nice, nohup, time.  These commands can also be used by themselves,
	 * and this is not handled here. This will also work when loops are
	 * parsed.
	 */
	while (t->t_dtyp == NODE_COMMAND)
	    if (eq(t->t_dcom[0], STRnice))
		if (t->t_dcom[1])
		    if (strchr("+-", t->t_dcom[1][0]))
			if (t->t_dcom[2]) {
			    setname("nice");
			    t->t_nice =
				getn(t->t_dcom[1]);
			    lshift(t->t_dcom, 2);
			    t->t_dflg |= F_NICE;
			}
			else
			    break;
		    else {
			t->t_nice = 4;
			lshift(t->t_dcom, 1);
			t->t_dflg |= F_NICE;
		    }
		else
		    break;
	    else if (eq(t->t_dcom[0], STRnohup))
		if (t->t_dcom[1]) {
		    t->t_dflg |= F_NOHUP;
		    lshift(t->t_dcom, 1);
		}
		else
		    break;
	    else if (eq(t->t_dcom[0], STRtime))
		if (t->t_dcom[1]) {
		    t->t_dflg |= F_TIME;
		    lshift(t->t_dcom, 1);
		}
		else
		    break;
	    else
		break;

	/* is it a command */
	if (t->t_dtyp == NODE_COMMAND) {
	    /*
	     * Check if we have a builtin function and remember which one.
	     */
	    bifunc = isbfunc(t);
	    if (noexec) {
		/*
		 * Continue for builtins that are part of the scripting language
		 */
		if (bifunc &&
		    bifunc->bfunct != dobreak   && bifunc->bfunct != docontin &&
		    bifunc->bfunct != doelse    && bifunc->bfunct != doend    &&
		    bifunc->bfunct != doforeach && bifunc->bfunct != dogoto   &&
		    bifunc->bfunct != doif      && bifunc->bfunct != dorepeat &&
		    bifunc->bfunct != doswbrk   && bifunc->bfunct != doswitch &&
		    bifunc->bfunct != dowhile   && bifunc->bfunct != dozip)
		    break;
	    }
	}
	else {			/* not a command */
	    bifunc = NULL;
	    if (noexec)
		break;
	}

	/*
	 * We fork only if we are timed, or are not the end of a parenthesized
	 * list and not a simple builtin function. Simple meaning one that is
	 * not pipedout, niced, nohupped, or &'d. It would be nice(?) to not
	 * fork in some of these cases.
	 */
	/*
	 * Prevent forking cd, pushd, popd, chdir cause this will cause the
	 * shell not to change dir!
	 */
	if (bifunc && (bifunc->bfunct == dochngd ||
		       bifunc->bfunct == dopushd ||
		       bifunc->bfunct == dopopd))
	    t->t_dflg &= ~(F_NICE);
	if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 &&
	     (!bifunc || t->t_dflg &
	      (F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP)))) ||
	/*
	 * We have to fork for eval too.
	 */
	    (bifunc && (t->t_dflg & (F_PIPEIN | F_PIPEOUT)) != 0 &&
	     bifunc->bfunct == doeval)) {
	    if (t->t_dtyp == NODE_PAREN ||
		t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc) {
		forked++;
		/*
		 * We need to block SIGCHLD here, so that if the process does
		 * not die before we can set the process group
		 */
		if (wanttty >= 0 && !nosigchld) {
		    sigemptyset(&sigset);
		    sigaddset(&sigset, SIGCHLD);
		    sigprocmask(SIG_BLOCK, &sigset, &csigset);
		    nosigchld = 1;
		}

		pid = pfork(t, wanttty);
		if (pid == 0 && nosigchld) {
		    sigprocmask(SIG_SETMASK, &csigset, NULL);
		    nosigchld = 0;
		}
		else if (pid != 0 && (t->t_dflg & F_AMPERSAND))
		    backpid = pid;

	    }
	    else {
		int     ochild, osetintr, ohaderr, odidfds;
		int     oSHIN, oSHOUT, oSHERR, oOLDSTD, otpgrp;
		sigset_t osigset;

		/*
		 * Prepare for the vfork by saving everything that the child
		 * corrupts before it exec's. Note that in some signal
		 * implementations which keep the signal info in user space
		 * (e.g. Sun's) it will also be necessary to save and restore
		 * the current sigaction's for the signals the child touches
		 * before it exec's.
		 */
		if (wanttty >= 0 && !nosigchld && !noexec) {
		    sigemptyset(&sigset);
		    sigaddset(&sigset, SIGCHLD);
		    sigprocmask(SIG_BLOCK, &sigset, &csigset);
		    nosigchld = 1;
		}
		sigemptyset(&sigset);
		sigaddset(&sigset, SIGCHLD);
		sigaddset(&sigset, SIGINT);
		sigprocmask(SIG_BLOCK, &sigset, &osigset);
		ochild = child;
		osetintr = setintr;
		ohaderr = haderr;
		odidfds = didfds;
		oSHIN = SHIN;
		oSHOUT = SHOUT;
		oSHERR = SHERR;
		oOLDSTD = OLDSTD;
		otpgrp = tpgrp;
		ocsigset = csigset;
		onosigchld = nosigchld;
		Vsav = Vdp = 0;
		Vexpath = 0;
		Vt = 0;
		pid = vfork();

		if (pid < 0) {
		    sigprocmask(SIG_SETMASK, &osigset, NULL);
		    stderror(ERR_NOPROC);
		}
		forked++;
		if (pid) {	/* parent */
		    child = ochild;
		    setintr = osetintr;
		    haderr = ohaderr;
		    didfds = odidfds;
		    SHIN = oSHIN;
		    SHOUT = oSHOUT;
		    SHERR = oSHERR;
		    OLDSTD = oOLDSTD;
		    tpgrp = otpgrp;
		    csigset = ocsigset;
		    nosigchld = onosigchld;

		    xfree((ptr_t) Vsav);
		    Vsav = 0;
		    xfree((ptr_t) Vdp);
		    Vdp = 0;
		    xfree((ptr_t) Vexpath);
		    Vexpath = 0;
		    blkfree((Char **) Vt);
		    Vt = 0;
		    /* this is from pfork() */
		    palloc(pid, t);
		    sigprocmask(SIG_SETMASK, &osigset, NULL);
		}
		else {		/* child */
		    /* this is from pfork() */
		    int     pgrp;
		    bool    ignint = 0;

		    if (nosigchld) {
			sigprocmask(SIG_SETMASK, &csigset, NULL);
			nosigchld = 0;
		    }

		    if (setintr)
			ignint =
			    (tpgrp == -1 &&
			     (t->t_dflg & F_NOINTERRUPT))
			    || (gointr && eq(gointr, STRminus));
		    pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
		    child++;
		    if (setintr) {
			setintr = 0;
			if (ignint) {
			    (void) signal(SIGINT, SIG_IGN);
			    (void) signal(SIGQUIT, SIG_IGN);
			}
			else {
			    (void) signal(SIGINT, vffree);
			    (void) signal(SIGQUIT, SIG_DFL);
			}

			if (wanttty >= 0) {
			    (void) signal(SIGTSTP, SIG_DFL);
			    (void) signal(SIGTTIN, SIG_DFL);
			    (void) signal(SIGTTOU, SIG_DFL);
			}

			(void) signal(SIGTERM, parterm);
		    }
		    else if (tpgrp == -1 &&
			     (t->t_dflg & F_NOINTERRUPT)) {
			(void) signal(SIGINT, SIG_IGN);
			(void) signal(SIGQUIT, SIG_IGN);
		    }

		    pgetty(wanttty, pgrp);
		    if (t->t_dflg & F_NOHUP)
			(void) signal(SIGHUP, SIG_IGN);
		    if (t->t_dflg & F_NICE)
			(void) setpriority(PRIO_PROCESS, 0, t->t_nice);
		}

	    }
	}
	if (pid != 0) {
	    /*
	     * It would be better if we could wait for the whole job when we
	     * knew the last process had been started.  Pwait, in fact, does
	     * wait for the whole job anyway, but this test doesn't really
	     * express our intentions.
	     */
	    if (didfds == 0 && t->t_dflg & F_PIPEIN) {
		(void) close(pipein[0]);
		(void) close(pipein[1]);
	    }
	    if ((t->t_dflg & F_PIPEOUT) == 0) {
		if (nosigchld) {
		    sigprocmask(SIG_SETMASK, &csigset, NULL);
		    nosigchld = 0;
		}
		if ((t->t_dflg & F_AMPERSAND) == 0)
		    pwait();
	    }
	    break;
	}
	doio(t, pipein, pipeout);
	if (t->t_dflg & F_PIPEOUT) {
	    (void) close(pipeout[0]);
	    (void) close(pipeout[1]);
	}
	/*
	 * Perform a builtin function. If we are not forked, arrange for
	 * possible stopping
	 */
	if (bifunc) {
	    func(t, bifunc);
	    if (forked)
		exitstat();
	    break;
	}
	if (t->t_dtyp != NODE_PAREN) {
	    doexec(NULL, t);
	    /* NOTREACHED */
	}
	/*
	 * For () commands must put new 0,1,2 in FSH* and recurse
	 */
	OLDSTD = dcopy(0, FOLDSTD);
	SHOUT = dcopy(1, FSHOUT);
	SHERR = dcopy(2, FSHERR);
	(void) close(SHIN);
	SHIN = -1;
	didfds = 0;
	wanttty = -1;
	t->t_dspr->t_dflg |= t->t_dflg & F_NOINTERRUPT;
	execute(t->t_dspr, wanttty, NULL, NULL);
	exitstat();

    case NODE_PIPE:
	t->t_dcar->t_dflg |= F_PIPEOUT |
	    (t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT));
	execute(t->t_dcar, wanttty, pipein, pv);
	t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg &
			(F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT));
	if (wanttty > 0)
	    wanttty = 0;	/* got tty already */
	execute(t->t_dcdr, wanttty, pv, pipeout);
	break;

    case NODE_LIST:
	if (t->t_dcar) {
	    t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT;
	    execute(t->t_dcar, wanttty, NULL, NULL);
	    /*
	     * In strange case of A&B make a new job after A
	     */
	    if (t->t_dcar->t_dflg & F_AMPERSAND && t->t_dcdr &&
		(t->t_dcdr->t_dflg & F_AMPERSAND) == 0)
		pendjob();
	}
	if (t->t_dcdr) {
	    t->t_dcdr->t_dflg |= t->t_dflg &
		(F_NOFORK | F_NOINTERRUPT);
	    execute(t->t_dcdr, wanttty, NULL, NULL);
	}
	break;

    case NODE_OR:
    case NODE_AND:
	if (t->t_dcar) {
	    t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT;
	    execute(t->t_dcar, wanttty, NULL, NULL);
	    if ((getn(value(STRstatus)) == 0) !=
		(t->t_dtyp == NODE_AND))
		return;
	}
	if (t->t_dcdr) {
	    t->t_dcdr->t_dflg |= t->t_dflg &
		(F_NOFORK | F_NOINTERRUPT);
	    execute(t->t_dcdr, wanttty, NULL, NULL);
	}
	break;
    }
    /*
     * Fall through for all breaks from switch
     *
     * If there will be no more executions of this command, flush all file
     * descriptors. Places that turn on the F_REPEAT bit are responsible for
     * doing donefds after the last re-execution
     */
    if (didfds && !(t->t_dflg & F_REPEAT))
	donefds();
}

static void
vffree(int i)
{
    _exit(i);
}

/*
 * Expand and glob the words after an i/o redirection.
 * If more than one word is generated, then update the command vector.
 *
 * This is done differently in all the shells:
 * 1. in the bourne shell and ksh globbing is not performed
 * 2. Bash/csh say ambiguous
 * 3. zsh does i/o to/from all the files
 * 4. itcsh concatenates the words.
 *
 * I don't know what is best to do. I think that Ambiguous is better
 * than restructuring the command vector, because the user can get
 * unexpected results. In any case, the command vector restructuring
 * code is present and the user can choose it by setting noambiguous
 */
static Char *
splicepipe(struct command *t, Char *cp) /* word after < or > */
{
    Char *blk[2];

    if (adrof(STRnoambiguous)) {
	Char **pv;

	blk[0] = Dfix1(cp); /* expand $ */
	blk[1] = NULL;

	gflag = 0, tglob(blk);
	if (gflag) {
	    pv = globall(blk);
	    if (pv == NULL) {
		setname(vis_str(blk[0]));
		xfree((ptr_t) blk[0]);
		stderror(ERR_NAME | ERR_NOMATCH);
	    }
	    gargv = NULL;
	    if (pv[1] != NULL) { /* we need to fix the command vector */
		Char **av = blkspl(t->t_dcom, &pv[1]);
		xfree((ptr_t) t->t_dcom);
		t->t_dcom = av;
	    }
	    xfree((ptr_t) blk[0]);
	    blk[0] = pv[0];
	    xfree((ptr_t) pv);
	}
    }
    else {
	blk[0] = globone(blk[1] = Dfix1(cp), G_ERROR);
	xfree((ptr_t) blk[1]);
    }
    return(blk[0]);
}

/*
 * Perform io redirection.
 * We may or maynot be forked here.
 */
static void
doio(struct command *t, int *pipein, int *pipeout)
{
    int fd;
    Char *cp;
    int flags = t->t_dflg;

    if (didfds || (flags & F_REPEAT))
	return;
    if ((flags & F_READ) == 0) {/* F_READ already done */
	if (t->t_dlef) {
	    char    tmp[MAXPATHLEN];

	    /*
	     * so < /dev/std{in,out,err} work
	     */
	    (void) dcopy(SHIN, 0);
	    (void) dcopy(SHOUT, 1);
	    (void) dcopy(SHERR, 2);
	    cp = splicepipe(t, t->t_dlef);
	    strlcpy(tmp, short2str(cp), sizeof tmp);
	    xfree((ptr_t) cp);
	    if ((fd = open(tmp, O_RDONLY)) < 0)
		stderror(ERR_SYSTEM, tmp, strerror(errno));
	    (void) dmove(fd, 0);
	}
	else if (flags & F_PIPEIN) {
	    (void) close(0);
	    (void) dup(pipein[0]);
	    (void) close(pipein[0]);
	    (void) close(pipein[1]);
	}
	else if ((flags & F_NOINTERRUPT) && tpgrp == -1) {
	    (void) close(0);
	    (void) open(_PATH_DEVNULL, O_RDONLY);
	}
	else {
	    (void) close(0);
	    (void) dup(OLDSTD);
	    (void) ioctl(STDIN_FILENO, FIONCLEX, NULL);
	}
    }
    if (t->t_drit) {
	char    tmp[MAXPATHLEN];

	cp = splicepipe(t, t->t_drit);
	strlcpy(tmp, short2str(cp), sizeof tmp);
	xfree((ptr_t) cp);
	/*
	 * so > /dev/std{out,err} work
	 */
	(void) dcopy(SHOUT, 1);
	(void) dcopy(SHERR, 2);
	if ((flags & F_APPEND) &&
#ifdef O_APPEND
	    (fd = open(tmp, O_WRONLY | O_APPEND)) >= 0);
#else
	    (fd = open(tmp, O_WRONLY)) >= 0)
	    (void) lseek(STDOUT_FILENO, (off_t) 0, SEEK_END);
#endif
	else {
	    if (!(flags & F_OVERWRITE) && adrof(STRnoclobber)) {
		if (flags & F_APPEND)
		    stderror(ERR_SYSTEM, tmp, strerror(errno));
		chkclob(tmp);
	    }
	    if ((fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 0666)) < 0)
		stderror(ERR_SYSTEM, tmp, strerror(errno));
	}
	(void) dmove(fd, 1);
    }
    else if (flags & F_PIPEOUT) {
	(void) close(1);
	(void) dup(pipeout[1]);
    }
    else {
	(void) close(1);
	(void) dup(SHOUT);
	(void) ioctl(STDOUT_FILENO, FIONCLEX, NULL);
    }

    (void) close(2);
    if (flags & F_STDERR) {
	(void) dup(1);
    }
    else {
	(void) dup(SHERR);
	(void) ioctl(STDERR_FILENO, FIONCLEX, NULL);
    }
    didfds = 1;
}

void
mypipe(int *pv)
{

    if (pipe(pv) < 0)
	goto oops;
    pv[0] = dmove(pv[0], -1);
    pv[1] = dmove(pv[1], -1);
    if (pv[0] >= 0 && pv[1] >= 0)
	return;
oops:
    stderror(ERR_PIPE);
}

static void
chkclob(char *cp)
{
    struct stat stb;

    if (stat(cp, &stb) < 0)
	return;
    if (S_ISCHR(stb.st_mode))
	return;
    stderror(ERR_EXISTS, cp);
}