1 /*
2  * OS specific functions for UNIX/POSIX systems
3  * Copyright (c) 2005-2009, Jouni Malinen <j@w1.fi>
4  *
5  * This software may be distributed under the terms of the BSD license.
6  * See README for more details.
7  */
8 
9 #include "includes.h"
10 
11 #include <time.h>
12 #include <sys/wait.h>
13 
14 #ifdef ANDROID
15 #include <sys/capability.h>
16 #include <sys/prctl.h>
17 #include <private/android_filesystem_config.h>
18 #endif /* ANDROID */
19 
20 #ifdef __MACH__
21 #include <CoreServices/CoreServices.h>
22 #include <mach/mach.h>
23 #include <mach/mach_time.h>
24 #endif /* __MACH__ */
25 
26 #include "os.h"
27 #include "common.h"
28 
29 #ifdef WPA_TRACE
30 
31 #include "wpa_debug.h"
32 #include "trace.h"
33 #include "list.h"
34 
35 static struct dl_list alloc_list = DL_LIST_HEAD_INIT(alloc_list);
36 
37 #define ALLOC_MAGIC 0xa84ef1b2
38 #define FREED_MAGIC 0x67fd487a
39 
40 struct os_alloc_trace {
41 	unsigned int magic;
42 	struct dl_list list;
43 	size_t len;
44 	WPA_TRACE_INFO
45 } __attribute__((aligned(16)));
46 
47 #endif /* WPA_TRACE */
48 
49 
os_sleep(os_time_t sec,os_time_t usec)50 void os_sleep(os_time_t sec, os_time_t usec)
51 {
52 	if (sec)
53 		sleep(sec);
54 	if (usec)
55 		usleep(usec);
56 }
57 
58 
os_get_time(struct os_time * t)59 int os_get_time(struct os_time *t)
60 {
61 	int res;
62 	struct timeval tv;
63 	res = gettimeofday(&tv, NULL);
64 	t->sec = tv.tv_sec;
65 	t->usec = tv.tv_usec;
66 	return res;
67 }
68 
69 
os_get_reltime(struct os_reltime * t)70 int os_get_reltime(struct os_reltime *t)
71 {
72 #ifndef __MACH__
73 #if defined(CLOCK_BOOTTIME)
74 	static clockid_t clock_id = CLOCK_BOOTTIME;
75 #elif defined(CLOCK_MONOTONIC)
76 	static clockid_t clock_id = CLOCK_MONOTONIC;
77 #else
78 	static clockid_t clock_id = CLOCK_REALTIME;
79 #endif
80 	struct timespec ts;
81 	int res;
82 
83 	if (TEST_FAIL())
84 		return -1;
85 
86 	while (1) {
87 		res = clock_gettime(clock_id, &ts);
88 		if (res == 0) {
89 			t->sec = ts.tv_sec;
90 			t->usec = ts.tv_nsec / 1000;
91 			return 0;
92 		}
93 		switch (clock_id) {
94 #ifdef CLOCK_BOOTTIME
95 		case CLOCK_BOOTTIME:
96 			clock_id = CLOCK_MONOTONIC;
97 			break;
98 #endif
99 #ifdef CLOCK_MONOTONIC
100 		case CLOCK_MONOTONIC:
101 			clock_id = CLOCK_REALTIME;
102 			break;
103 #endif
104 		case CLOCK_REALTIME:
105 			return -1;
106 		}
107 	}
108 #else /* __MACH__ */
109 	uint64_t abstime, nano;
110 	static mach_timebase_info_data_t info = { 0, 0 };
111 
112 	if (!info.denom) {
113 		if (mach_timebase_info(&info) != KERN_SUCCESS)
114 			return -1;
115 	}
116 
117 	abstime = mach_absolute_time();
118 	nano = (abstime * info.numer) / info.denom;
119 
120 	t->sec = nano / NSEC_PER_SEC;
121 	t->usec = (nano - (((uint64_t) t->sec) * NSEC_PER_SEC)) / NSEC_PER_USEC;
122 
123 	return 0;
124 #endif /* __MACH__ */
125 }
126 
127 
os_mktime(int year,int month,int day,int hour,int min,int sec,os_time_t * t)128 int os_mktime(int year, int month, int day, int hour, int min, int sec,
129 	      os_time_t *t)
130 {
131 	struct tm tm, *tm1;
132 	time_t t_local, t1, t2;
133 	os_time_t tz_offset;
134 
135 	if (year < 1970 || month < 1 || month > 12 || day < 1 || day > 31 ||
136 	    hour < 0 || hour > 23 || min < 0 || min > 59 || sec < 0 ||
137 	    sec > 60)
138 		return -1;
139 
140 	memset(&tm, 0, sizeof(tm));
141 	tm.tm_year = year - 1900;
142 	tm.tm_mon = month - 1;
143 	tm.tm_mday = day;
144 	tm.tm_hour = hour;
145 	tm.tm_min = min;
146 	tm.tm_sec = sec;
147 
148 	t_local = mktime(&tm);
149 
150 	/* figure out offset to UTC */
151 	tm1 = localtime(&t_local);
152 	if (tm1) {
153 		t1 = mktime(tm1);
154 		tm1 = gmtime(&t_local);
155 		if (tm1) {
156 			t2 = mktime(tm1);
157 			tz_offset = t2 - t1;
158 		} else
159 			tz_offset = 0;
160 	} else
161 		tz_offset = 0;
162 
163 	*t = (os_time_t) t_local - tz_offset;
164 	return 0;
165 }
166 
167 
os_gmtime(os_time_t t,struct os_tm * tm)168 int os_gmtime(os_time_t t, struct os_tm *tm)
169 {
170 	struct tm *tm2;
171 	time_t t2 = t;
172 
173 	tm2 = gmtime(&t2);
174 	if (tm2 == NULL)
175 		return -1;
176 	tm->sec = tm2->tm_sec;
177 	tm->min = tm2->tm_min;
178 	tm->hour = tm2->tm_hour;
179 	tm->day = tm2->tm_mday;
180 	tm->month = tm2->tm_mon + 1;
181 	tm->year = tm2->tm_year + 1900;
182 	return 0;
183 }
184 
185 
186 #ifdef __APPLE__
187 #include <fcntl.h>
os_daemon(int nochdir,int noclose)188 static int os_daemon(int nochdir, int noclose)
189 {
190 	int devnull;
191 
192 	if (chdir("/") < 0)
193 		return -1;
194 
195 	devnull = open("/dev/null", O_RDWR);
196 	if (devnull < 0)
197 		return -1;
198 
199 	if (dup2(devnull, STDIN_FILENO) < 0) {
200 		close(devnull);
201 		return -1;
202 	}
203 
204 	if (dup2(devnull, STDOUT_FILENO) < 0) {
205 		close(devnull);
206 		return -1;
207 	}
208 
209 	if (dup2(devnull, STDERR_FILENO) < 0) {
210 		close(devnull);
211 		return -1;
212 	}
213 
214 	return 0;
215 }
216 #else /* __APPLE__ */
217 #define os_daemon daemon
218 #endif /* __APPLE__ */
219 
220 
os_daemonize(const char * pid_file)221 int os_daemonize(const char *pid_file)
222 {
223 #if defined(__uClinux__) || defined(__sun__)
224 	return -1;
225 #else /* defined(__uClinux__) || defined(__sun__) */
226 	if (os_daemon(0, 0)) {
227 		perror("daemon");
228 		return -1;
229 	}
230 
231 	if (pid_file) {
232 		FILE *f = fopen(pid_file, "w");
233 		if (f) {
234 			fprintf(f, "%u\n", getpid());
235 			fclose(f);
236 		}
237 	}
238 
239 	return -0;
240 #endif /* defined(__uClinux__) || defined(__sun__) */
241 }
242 
243 
os_daemonize_terminate(const char * pid_file)244 void os_daemonize_terminate(const char *pid_file)
245 {
246 	if (pid_file)
247 		unlink(pid_file);
248 }
249 
250 
os_get_random(unsigned char * buf,size_t len)251 int os_get_random(unsigned char *buf, size_t len)
252 {
253 	FILE *f;
254 	size_t rc;
255 
256 	if (TEST_FAIL())
257 		return -1;
258 
259 	f = fopen("/dev/urandom", "rb");
260 	if (f == NULL) {
261 		printf("Could not open /dev/urandom.\n");
262 		return -1;
263 	}
264 
265 	rc = fread(buf, 1, len, f);
266 	fclose(f);
267 
268 	return rc != len ? -1 : 0;
269 }
270 
271 
os_random(void)272 unsigned long os_random(void)
273 {
274 	return random();
275 }
276 
277 
os_rel2abs_path(const char * rel_path)278 char * os_rel2abs_path(const char *rel_path)
279 {
280 	char *buf = NULL, *cwd, *ret;
281 	size_t len = 128, cwd_len, rel_len, ret_len;
282 	int last_errno;
283 
284 	if (!rel_path)
285 		return NULL;
286 
287 	if (rel_path[0] == '/')
288 		return os_strdup(rel_path);
289 
290 	for (;;) {
291 		buf = os_malloc(len);
292 		if (buf == NULL)
293 			return NULL;
294 		cwd = getcwd(buf, len);
295 		if (cwd == NULL) {
296 			last_errno = errno;
297 			os_free(buf);
298 			if (last_errno != ERANGE)
299 				return NULL;
300 			len *= 2;
301 			if (len > 2000)
302 				return NULL;
303 		} else {
304 			buf[len - 1] = '\0';
305 			break;
306 		}
307 	}
308 
309 	cwd_len = os_strlen(cwd);
310 	rel_len = os_strlen(rel_path);
311 	ret_len = cwd_len + 1 + rel_len + 1;
312 	ret = os_malloc(ret_len);
313 	if (ret) {
314 		os_memcpy(ret, cwd, cwd_len);
315 		ret[cwd_len] = '/';
316 		os_memcpy(ret + cwd_len + 1, rel_path, rel_len);
317 		ret[ret_len - 1] = '\0';
318 	}
319 	os_free(buf);
320 	return ret;
321 }
322 
323 
os_program_init(void)324 int os_program_init(void)
325 {
326 #ifdef ANDROID
327 	/*
328 	 * We ignore errors here since errors are normal if we
329 	 * are already running as non-root.
330 	 */
331 #ifdef ANDROID_SETGROUPS_OVERRIDE
332 	gid_t groups[] = { ANDROID_SETGROUPS_OVERRIDE };
333 #else /* ANDROID_SETGROUPS_OVERRIDE */
334 	gid_t groups[] = { AID_INET, AID_WIFI, AID_KEYSTORE };
335 #endif /* ANDROID_SETGROUPS_OVERRIDE */
336 	struct __user_cap_header_struct header;
337 	struct __user_cap_data_struct cap;
338 
339 	setgroups(ARRAY_SIZE(groups), groups);
340 
341 	prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0);
342 
343 	setgid(AID_WIFI);
344 	setuid(AID_WIFI);
345 
346 	header.version = _LINUX_CAPABILITY_VERSION;
347 	header.pid = 0;
348 	cap.effective = cap.permitted =
349 		(1 << CAP_NET_ADMIN) | (1 << CAP_NET_RAW);
350 	cap.inheritable = 0;
351 	capset(&header, &cap);
352 #endif /* ANDROID */
353 
354 	return 0;
355 }
356 
357 
os_program_deinit(void)358 void os_program_deinit(void)
359 {
360 #ifdef WPA_TRACE
361 	struct os_alloc_trace *a;
362 	unsigned long total = 0;
363 	dl_list_for_each(a, &alloc_list, struct os_alloc_trace, list) {
364 		total += a->len;
365 		if (a->magic != ALLOC_MAGIC) {
366 			wpa_printf(MSG_INFO, "MEMLEAK[%p]: invalid magic 0x%x "
367 				   "len %lu",
368 				   a, a->magic, (unsigned long) a->len);
369 			continue;
370 		}
371 		wpa_printf(MSG_INFO, "MEMLEAK[%p]: len %lu",
372 			   a, (unsigned long) a->len);
373 		wpa_trace_dump("memleak", a);
374 	}
375 	if (total)
376 		wpa_printf(MSG_INFO, "MEMLEAK: total %lu bytes",
377 			   (unsigned long) total);
378 	wpa_trace_deinit();
379 #endif /* WPA_TRACE */
380 }
381 
382 
os_setenv(const char * name,const char * value,int overwrite)383 int os_setenv(const char *name, const char *value, int overwrite)
384 {
385 	return setenv(name, value, overwrite);
386 }
387 
388 
os_unsetenv(const char * name)389 int os_unsetenv(const char *name)
390 {
391 #if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__APPLE__) || \
392     defined(__OpenBSD__)
393 	unsetenv(name);
394 	return 0;
395 #else
396 	return unsetenv(name);
397 #endif
398 }
399 
400 
os_readfile(const char * name,size_t * len)401 char * os_readfile(const char *name, size_t *len)
402 {
403 	FILE *f;
404 	char *buf;
405 	long pos;
406 
407 	f = fopen(name, "rb");
408 	if (f == NULL)
409 		return NULL;
410 
411 	if (fseek(f, 0, SEEK_END) < 0 || (pos = ftell(f)) < 0) {
412 		fclose(f);
413 		return NULL;
414 	}
415 	*len = pos;
416 	if (fseek(f, 0, SEEK_SET) < 0) {
417 		fclose(f);
418 		return NULL;
419 	}
420 
421 	buf = os_malloc(*len);
422 	if (buf == NULL) {
423 		fclose(f);
424 		return NULL;
425 	}
426 
427 	if (fread(buf, 1, *len, f) != *len) {
428 		fclose(f);
429 		os_free(buf);
430 		return NULL;
431 	}
432 
433 	fclose(f);
434 
435 	return buf;
436 }
437 
438 
os_file_exists(const char * fname)439 int os_file_exists(const char *fname)
440 {
441 	return access(fname, F_OK) == 0;
442 }
443 
444 
os_fdatasync(FILE * stream)445 int os_fdatasync(FILE *stream)
446 {
447 	if (!fflush(stream)) {
448 #ifdef __linux__
449 		return fdatasync(fileno(stream));
450 #else /* !__linux__ */
451 #ifdef F_FULLFSYNC
452 		/* OS X does not implement fdatasync(). */
453 		return fcntl(fileno(stream), F_FULLFSYNC);
454 #else /* F_FULLFSYNC */
455 		return fsync(fileno(stream));
456 #endif /* F_FULLFSYNC */
457 #endif /* __linux__ */
458 	}
459 
460 	return -1;
461 }
462 
463 
464 #ifndef WPA_TRACE
os_zalloc(size_t size)465 void * os_zalloc(size_t size)
466 {
467 	return calloc(1, size);
468 }
469 #endif /* WPA_TRACE */
470 
471 
os_strlcpy(char * dest,const char * src,size_t siz)472 size_t os_strlcpy(char *dest, const char *src, size_t siz)
473 {
474 	const char *s = src;
475 	size_t left = siz;
476 
477 	if (left) {
478 		/* Copy string up to the maximum size of the dest buffer */
479 		while (--left != 0) {
480 			if ((*dest++ = *s++) == '\0')
481 				break;
482 		}
483 	}
484 
485 	if (left == 0) {
486 		/* Not enough room for the string; force NUL-termination */
487 		if (siz != 0)
488 			*dest = '\0';
489 		while (*s++)
490 			; /* determine total src string length */
491 	}
492 
493 	return s - src - 1;
494 }
495 
496 
os_memcmp_const(const void * a,const void * b,size_t len)497 int os_memcmp_const(const void *a, const void *b, size_t len)
498 {
499 	const u8 *aa = a;
500 	const u8 *bb = b;
501 	size_t i;
502 	u8 res;
503 
504 	for (res = 0, i = 0; i < len; i++)
505 		res |= aa[i] ^ bb[i];
506 
507 	return res;
508 }
509 
510 
511 #ifdef WPA_TRACE
512 
513 #if defined(WPA_TRACE_BFD) && defined(CONFIG_TESTING_OPTIONS)
514 char wpa_trace_fail_func[256] = { 0 };
515 unsigned int wpa_trace_fail_after;
516 
testing_fail_alloc(void)517 static int testing_fail_alloc(void)
518 {
519 	const char *func[WPA_TRACE_LEN];
520 	size_t i, res, len;
521 	char *pos, *next;
522 	int match;
523 
524 	if (!wpa_trace_fail_after)
525 		return 0;
526 
527 	res = wpa_trace_calling_func(func, WPA_TRACE_LEN);
528 	i = 0;
529 	if (i < res && os_strcmp(func[i], __func__) == 0)
530 		i++;
531 	if (i < res && os_strcmp(func[i], "os_malloc") == 0)
532 		i++;
533 	if (i < res && os_strcmp(func[i], "os_zalloc") == 0)
534 		i++;
535 	if (i < res && os_strcmp(func[i], "os_calloc") == 0)
536 		i++;
537 	if (i < res && os_strcmp(func[i], "os_realloc") == 0)
538 		i++;
539 	if (i < res && os_strcmp(func[i], "os_realloc_array") == 0)
540 		i++;
541 	if (i < res && os_strcmp(func[i], "os_strdup") == 0)
542 		i++;
543 
544 	pos = wpa_trace_fail_func;
545 
546 	match = 0;
547 	while (i < res) {
548 		int allow_skip = 1;
549 		int maybe = 0;
550 
551 		if (*pos == '=') {
552 			allow_skip = 0;
553 			pos++;
554 		} else if (*pos == '?') {
555 			maybe = 1;
556 			pos++;
557 		}
558 		next = os_strchr(pos, ';');
559 		if (next)
560 			len = next - pos;
561 		else
562 			len = os_strlen(pos);
563 		if (os_memcmp(pos, func[i], len) != 0) {
564 			if (maybe && next) {
565 				pos = next + 1;
566 				continue;
567 			}
568 			if (allow_skip) {
569 				i++;
570 				continue;
571 			}
572 			return 0;
573 		}
574 		if (!next) {
575 			match = 1;
576 			break;
577 		}
578 		pos = next + 1;
579 		i++;
580 	}
581 	if (!match)
582 		return 0;
583 
584 	wpa_trace_fail_after--;
585 	if (wpa_trace_fail_after == 0) {
586 		wpa_printf(MSG_INFO, "TESTING: fail allocation at %s",
587 			   wpa_trace_fail_func);
588 		for (i = 0; i < res; i++)
589 			wpa_printf(MSG_INFO, "backtrace[%d] = %s",
590 				   (int) i, func[i]);
591 		return 1;
592 	}
593 
594 	return 0;
595 }
596 
597 
598 char wpa_trace_test_fail_func[256] = { 0 };
599 unsigned int wpa_trace_test_fail_after;
600 
testing_test_fail(void)601 int testing_test_fail(void)
602 {
603 	const char *func[WPA_TRACE_LEN];
604 	size_t i, res, len;
605 	char *pos, *next;
606 	int match;
607 
608 	if (!wpa_trace_test_fail_after)
609 		return 0;
610 
611 	res = wpa_trace_calling_func(func, WPA_TRACE_LEN);
612 	i = 0;
613 	if (i < res && os_strcmp(func[i], __func__) == 0)
614 		i++;
615 
616 	pos = wpa_trace_test_fail_func;
617 
618 	match = 0;
619 	while (i < res) {
620 		int allow_skip = 1;
621 		int maybe = 0;
622 
623 		if (*pos == '=') {
624 			allow_skip = 0;
625 			pos++;
626 		} else if (*pos == '?') {
627 			maybe = 1;
628 			pos++;
629 		}
630 		next = os_strchr(pos, ';');
631 		if (next)
632 			len = next - pos;
633 		else
634 			len = os_strlen(pos);
635 		if (os_memcmp(pos, func[i], len) != 0) {
636 			if (maybe && next) {
637 				pos = next + 1;
638 				continue;
639 			}
640 			if (allow_skip) {
641 				i++;
642 				continue;
643 			}
644 			return 0;
645 		}
646 		if (!next) {
647 			match = 1;
648 			break;
649 		}
650 		pos = next + 1;
651 		i++;
652 	}
653 	if (!match)
654 		return 0;
655 
656 	wpa_trace_test_fail_after--;
657 	if (wpa_trace_test_fail_after == 0) {
658 		wpa_printf(MSG_INFO, "TESTING: fail at %s",
659 			   wpa_trace_test_fail_func);
660 		for (i = 0; i < res; i++)
661 			wpa_printf(MSG_INFO, "backtrace[%d] = %s",
662 				   (int) i, func[i]);
663 		return 1;
664 	}
665 
666 	return 0;
667 }
668 
669 #else
670 
testing_fail_alloc(void)671 static inline int testing_fail_alloc(void)
672 {
673 	return 0;
674 }
675 #endif
676 
os_malloc(size_t size)677 void * os_malloc(size_t size)
678 {
679 	struct os_alloc_trace *a;
680 
681 	if (testing_fail_alloc())
682 		return NULL;
683 
684 	a = malloc(sizeof(*a) + size);
685 	if (a == NULL)
686 		return NULL;
687 	a->magic = ALLOC_MAGIC;
688 	dl_list_add(&alloc_list, &a->list);
689 	a->len = size;
690 	wpa_trace_record(a);
691 	return a + 1;
692 }
693 
694 
os_realloc(void * ptr,size_t size)695 void * os_realloc(void *ptr, size_t size)
696 {
697 	struct os_alloc_trace *a;
698 	size_t copy_len;
699 	void *n;
700 
701 	if (ptr == NULL)
702 		return os_malloc(size);
703 
704 	a = (struct os_alloc_trace *) ptr - 1;
705 	if (a->magic != ALLOC_MAGIC) {
706 		wpa_printf(MSG_INFO, "REALLOC[%p]: invalid magic 0x%x%s",
707 			   a, a->magic,
708 			   a->magic == FREED_MAGIC ? " (already freed)" : "");
709 		wpa_trace_show("Invalid os_realloc() call");
710 		abort();
711 	}
712 	n = os_malloc(size);
713 	if (n == NULL)
714 		return NULL;
715 	copy_len = a->len;
716 	if (copy_len > size)
717 		copy_len = size;
718 	os_memcpy(n, a + 1, copy_len);
719 	os_free(ptr);
720 	return n;
721 }
722 
723 
os_free(void * ptr)724 void os_free(void *ptr)
725 {
726 	struct os_alloc_trace *a;
727 
728 	if (ptr == NULL)
729 		return;
730 	a = (struct os_alloc_trace *) ptr - 1;
731 	if (a->magic != ALLOC_MAGIC) {
732 		wpa_printf(MSG_INFO, "FREE[%p]: invalid magic 0x%x%s",
733 			   a, a->magic,
734 			   a->magic == FREED_MAGIC ? " (already freed)" : "");
735 		wpa_trace_show("Invalid os_free() call");
736 		abort();
737 	}
738 	dl_list_del(&a->list);
739 	a->magic = FREED_MAGIC;
740 
741 	wpa_trace_check_ref(ptr);
742 	free(a);
743 }
744 
745 
os_zalloc(size_t size)746 void * os_zalloc(size_t size)
747 {
748 	void *ptr = os_malloc(size);
749 	if (ptr)
750 		os_memset(ptr, 0, size);
751 	return ptr;
752 }
753 
754 
os_strdup(const char * s)755 char * os_strdup(const char *s)
756 {
757 	size_t len;
758 	char *d;
759 	len = os_strlen(s);
760 	d = os_malloc(len + 1);
761 	if (d == NULL)
762 		return NULL;
763 	os_memcpy(d, s, len);
764 	d[len] = '\0';
765 	return d;
766 }
767 
768 #endif /* WPA_TRACE */
769 
770 
os_exec(const char * program,const char * arg,int wait_completion)771 int os_exec(const char *program, const char *arg, int wait_completion)
772 {
773 	pid_t pid;
774 	int pid_status;
775 
776 	pid = fork();
777 	if (pid < 0) {
778 		perror("fork");
779 		return -1;
780 	}
781 
782 	if (pid == 0) {
783 		/* run the external command in the child process */
784 		const int MAX_ARG = 30;
785 		char *_program, *_arg, *pos;
786 		char *argv[MAX_ARG + 1];
787 		int i;
788 
789 		_program = os_strdup(program);
790 		_arg = os_strdup(arg);
791 
792 		argv[0] = _program;
793 
794 		i = 1;
795 		pos = _arg;
796 		while (i < MAX_ARG && pos && *pos) {
797 			while (*pos == ' ')
798 				pos++;
799 			if (*pos == '\0')
800 				break;
801 			argv[i++] = pos;
802 			pos = os_strchr(pos, ' ');
803 			if (pos)
804 				*pos++ = '\0';
805 		}
806 		argv[i] = NULL;
807 
808 		execv(program, argv);
809 		perror("execv");
810 		os_free(_program);
811 		os_free(_arg);
812 		exit(0);
813 		return -1;
814 	}
815 
816 	if (wait_completion) {
817 		/* wait for the child process to complete in the parent */
818 		waitpid(pid, &pid_status, 0);
819 	}
820 
821 	return 0;
822 }
823