/usr/src/usr.bin/w/w.c

Bug Summary

File:	src/usr.bin/w/w.c
Warning:	line 369, column 9 Null pointer passed as 1st argument to string length function

Annotated Source Code

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Show analyzer invocation

clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name w.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/usr.bin/w/obj -resource-dir /usr/local/lib/clang/13.0.0 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/usr.bin/w/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/usr.bin/w/w.c

1/*	$OpenBSD: w.c,v 1.66 2019/06/28 13:35:05 deraadt Exp $	*/
2 
3/*-
4 * Copyright (c) 1980, 1991, 1993, 1994
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31 
32/*
33 * w - print system status (who and what)
34 *
35 * This program is similar to the systat command on Tenex/Tops 10/20
36 *
37 */
38#include <sys/param.h>	/* MAXCOMLEN */
39#include <sys/time.h>
40#include <sys/stat.h>
41#include <sys/sysctl.h>
42#include <sys/signal.h>
43#include <sys/proc.h>
44#include <sys/ioctl.h>
45#include <sys/socket.h>
46#include <sys/tty.h>
47 
48#include <netinet/in.h>
49#include <arpa/inet.h>
50 
51#include <ctype.h>
52#include <err.h>
53#include <errno(*__errno()).h>
54#include <fcntl.h>
55#include <kvm.h>
56#include <netdb.h>
57#include <nlist.h>
58#include <paths.h>
59#include <stdio.h>
60#include <stdlib.h>
61#include <string.h>
62#include <unistd.h>
63#include <limits.h>
64#include <utmp.h>
65#include <vis.h>
66 
67#include "extern.h"
68 
69struct utmp	utmp;
70struct winsize	ws;
71kvm_t	       *kd;
72time_t		now;		/* the current time of day */
73int		ttywidth;	/* width of tty */
74int		argwidth;	/* width of tty */
75int		header = 1;	/* true if -h flag: don't print heading */
76int		nflag = 1;	/* true if -n flag: don't convert addrs */
77int		sortidle;	/* sort by idle time */
78char	       *sel_user;	/* login of particular user selected */
79char		domain[HOST_NAME_MAX255+1];
80 
81#define	NAME_WIDTH8	8
82#define HOST_WIDTH16	16
83 
84/*
85 * One of these per active utmp entry.
86 */
87struct	entry {
88	struct	entry *next;
89	struct	utmp utmp;
90	dev_t	tdev;			/* dev_t of terminal */
91	time_t	idle;			/* idle time of terminal in seconds */
92	struct	kinfo_proc *kp;		/* `most interesting' proc */
93} *ep, *ehead = NULL((void *)0), **nextp = &ehead;
94 
95static void	 fmt_putc(int, int *);
96static void	 fmt_puts(const char *, int *);
97static void	 pr_args(struct kinfo_proc *);
98static void	 pr_header(time_t *, int);
99static struct stat
100		*ttystat(char *);
101static void	 usage(int);
102 
103int
104main(int argc, char *argv[])
105{
106	extern char *__progname;
107	struct kinfo_proc *kp;
108	struct hostent *hp;
109	struct stat *stp;
110	FILE *ut;
111	struct in_addr addr;
112	int ch, i, nentries, nusers, wcmd;
113	char *memf, *nlistf, *p, *x;
114	char buf[HOST_NAME_MAX255+1], errbuf[_POSIX2_LINE_MAX2048];
115 
116	/* Are we w(1) or uptime(1)? */
117	p = __progname;
118	if (*p == '-')
1
Assuming the condition is false→
2
←
Taking false branch→
119		p++;
120	if (p[0] == 'w' && p[1] == '\0') {
3
←
Assuming the condition is true→
4
←
Assuming the condition is true→
5
←
Taking true branch→
121		wcmd = 1;
122		p = "hiflM:N:asuw";
123	} else if (!strcmp(p, "uptime")) {
124		wcmd = 0;
125		p = "";
126	} else
127		errx(1,
128		 "this program should be invoked only as \"w\" or \"uptime\"");
129 
130	memf = nlistf = NULL((void *)0);
131	while ((ch = getopt(argc, argv, p)) != -1)
6
←
Assuming the condition is false→
7
←
Loop condition is false. Execution continues on line 156→
132		switch (ch) {
133		case 'h':
134			header = 0;
135			break;
136		case 'i':
137			sortidle = 1;
138			break;
139		case 'M':
140			header = 0;
141			memf = optarg;
142			break;
143		case 'N':
144			nlistf = optarg;
145			break;
146		case 'a':
147			nflag = 0;
148			break;
149		case 'f': case 'l': case 's': case 'u': case 'w':
150			warnx("[-flsuw] no longer supported");
151			/* FALLTHROUGH */
152		case '?':
153		default:
154			usage(wcmd);
155		}
156	argc -= optind;
157	argv += optind;
158 
159	if (nflag7.1
'nflag' is not equal to 0
 == 0) {
8
←
Taking false branch→
160		if (pledge("stdio tty rpath dns ps vminfo", NULL((void *)0)) == -1)
161			err(1, "pledge");
162	} else {
163		if (pledge("stdio tty rpath ps vminfo", NULL((void *)0)) == -1)
9
←
Assuming the condition is false→
10
←
Taking false branch→
164			err(1, "pledge");
165	}
166 
167	if (nlistf10.1
'nlistf' is equal to NULL
 == NULL((void *)0) && memf10.2
'memf' is equal to NULL
 == NULL((void *)0)) {
11
←
Taking true branch→
168		if ((kd = kvm_openfiles(nlistf, memf, NULL((void *)0), KVM_NO_FILES0x80000000,
12
←
Assuming the condition is false→
13
←
Taking false branch→
169		    errbuf)) == NULL((void *)0))
170			errx(1, "%s", errbuf);
171	} else {
172		if ((kd = kvm_openfiles(nlistf, memf, NULL((void *)0), O_RDONLY0x0000, errbuf)) == NULL((void *)0))
173			errx(1, "%s", errbuf);
174	}
175 
176	(void)time(&now);
177	if ((ut = fopen(_PATH_UTMP"/var/run/utmp", "r")) == NULL((void *)0))
14
←
Assuming the condition is false→
15
←
Taking false branch→
178		err(1, "%s", _PATH_UTMP"/var/run/utmp");
179 
180	if (*argv)
16
←
Assuming the condition is false→
17
←
Taking false branch→
181		sel_user = *argv;
182 
183	for (nusers = 0; fread(&utmp, sizeof(utmp), 1, ut);) {
18
←
Loop condition is true.  Entering loop body→
30
←
Loop condition is false. Execution continues on line 216→
184		if (utmp.ut_name[0] == '\0')
19
←
Assuming the condition is false→
20
←
Taking false branch→
185			continue;
186		++nusers;
187		if (wcmd20.1
'wcmd' is not equal to 0
 == 0 || (sel_user &&
21
←
Assuming 'sel_user' is null→
188		    strncmp(utmp.ut_name, sel_user, UT_NAMESIZE32) != 0))
189			continue;
190		if ((ep = calloc(1, sizeof(*ep))) == NULL((void *)0))
22
←
Assuming the condition is false→
23
←
Taking false branch→
191			err(1, NULL((void *)0));
192		*nextp = ep;
193		nextp = &(ep->next);
194		memcpy(&(ep->utmp), &utmp, sizeof(utmp));
195		if (!(stp = ttystat(ep->utmp.ut_line)))
24
←
Assuming 'stp' is non-null→
25
←
Taking false branch→
196			continue;
197		ep->tdev = stp->st_rdev;
198 
199		/*
200		 * If this is the console device, attempt to ascertain
201		 * the true console device dev_t.
202		 */
203		if (ep->tdev == 0) {
26
←
Assuming field 'tdev' is not equal to 0→
27
←
Taking false branch→
204			int mib[2];
205			size_t size;
206 
207			mib[0] = CTL_KERN1;
208			mib[1] = KERN_CONSDEV75;
209			size = sizeof(dev_t);
210			(void) sysctl(mib, 2, &ep->tdev, &size, NULL((void *)0), 0);
211		}
212 
213		if ((ep->idle = now - stp->st_atimest_atim.tv_sec) < 0)
28
←
Assuming the condition is false→
29
←
Taking false branch→
214			ep->idle = 0;
215	}
216	(void)fclose(ut);
217 
218	if (header || wcmd31.1
'wcmd' is not equal to 0
 == 0) {
31
←
Assuming 'header' is 0→
32
←
Taking false branch→
219		pr_header(&now, nusers);
220		if (wcmd == 0)
221			exit (0);
222	}
223 
224#define HEADER"USER    TTY FROM              LOGIN@  IDLE WHAT"	"USER    TTY FROM              LOGIN@  IDLE WHAT"
225#define WUSED(sizeof("USER    TTY FROM              LOGIN@  IDLE WHAT") - sizeof
("WHAT"))	(sizeof(HEADER"USER    TTY FROM              LOGIN@  IDLE WHAT") - sizeof("WHAT"))
226	if (header32.1
'header' is 0
)
33
←
Taking false branch→
227		(void)puts(HEADER"USER    TTY FROM              LOGIN@  IDLE WHAT");
228 
229	kp = kvm_getprocs(kd, KERN_PROC_ALL0, 0, sizeof(*kp), &nentries);
230	if (kp == NULL((void *)0))
34
←
Assuming 'kp' is not equal to NULL→
35
←
Taking false branch→
231		errx(1, "%s", kvm_geterr(kd));
232 
233	if ((ioctl(STDOUT_FILENO1, TIOCGWINSZ((unsigned long)0x40000000 | ((sizeof(struct winsize) & 0x1fff
) << 16) | ((('t')) << 8) | ((104))), &ws) == -1 &&
36
←
Assuming the condition is false→
38
←
Taking false branch→
234	    ioctl(STDERR_FILENO2, TIOCGWINSZ((unsigned long)0x40000000 | ((sizeof(struct winsize) & 0x1fff
) << 16) | ((('t')) << 8) | ((104))), &ws) == -1 &&
235	    ioctl(STDIN_FILENO0, TIOCGWINSZ((unsigned long)0x40000000 | ((sizeof(struct winsize) & 0x1fff
) << 16) | ((('t')) << 8) | ((104))), &ws) == -1) || ws.ws_col == 0)
37
←
Assuming field 'ws_col' is not equal to 0→
236		ttywidth = 79;
237	else
238		ttywidth = ws.ws_col - 1;
239	argwidth = ttywidth - WUSED(sizeof("USER    TTY FROM              LOGIN@  IDLE WHAT") - sizeof
("WHAT"));
240	if (argwidth < 4)
39
←
Assuming 'argwidth' is >= 4→
40
←
Taking false branch→
241		argwidth = 8;
242 
243	for (i = 0; i < nentries; i++, kp++) {
41
←
Assuming 'i' is >= 'nentries'→
42
←
Loop condition is false. Execution continues on line 272→
244		if (kp->p_psflags & (PS_EMBRYO0x00020000 | PS_ZOMBIE0x00040000))
245			continue;
246		for (ep = ehead; ep != NULL((void *)0); ep = ep->next) {
247			/* ftp is a special case. */
248			if (strncmp(ep->utmp.ut_line, "ftp", 3) == 0) {
249				char pidstr[UT_LINESIZE8-2];
250				pid_t fp;
251 
252				(void)strncpy(pidstr, &ep->utmp.ut_line[3],
253				    sizeof(pidstr) - 1);
254				pidstr[sizeof(pidstr) - 1] = '\0';
255				fp = (pid_t)strtol(pidstr, NULL((void *)0), 10);
256				if (kp->p_pid == fp) {
257					ep->kp = kp;
258					break;
259				}
260			} else if (ep->tdev == kp->p_tdev &&
261			    kp->p__pgid == kp->p_tpgid) {
262				/*
263				 * Proc is in foreground of this terminal
264				 */
265				if (proc_compare(ep->kp, kp))
266					ep->kp = kp;
267				break;
268			}
269		}
270	}
271	/* sort by idle time */
272	if (sortidle && ehead != NULL((void *)0)) {
43
←
Assuming 'sortidle' is 0→
273		struct entry *from = ehead, *save;
274 
275		ehead = NULL((void *)0);
276		while (from != NULL((void *)0)) {
277			for (nextp = &ehead;
278			    (*nextp) && from->idle >= (*nextp)->idle;
279			    nextp = &(*nextp)->next)
280				continue;
281			save = from;
282			from = from->next;
283			save->next = *nextp;
284			*nextp = save;
285		}
286	}
287 
288	if (!nflag) {
44
←
Assuming 'nflag' is not equal to 0→
45
←
Taking false branch→
289		if (gethostname(domain, sizeof(domain)) == -1 ||
290		    (p = strchr(domain, '.')) == 0)
291			domain[0] = '\0';
292		else {
293			domain[sizeof(domain) - 1] = '\0';
294			memmove(domain, p, strlen(p) + 1);
295		}
296	}
297 
298	for (ep = ehead; ep != NULL((void *)0); ep = ep->next) {
46
←
Assuming 'ep' is not equal to NULL→
47
←
Loop condition is true.  Entering loop body→
299		p = *ep->utmp.ut_host ? ep->utmp.ut_host : "-";
48
←
Assuming the condition is false→
49
←
'?' condition is false→
300		for (x = NULL((void *)0), i = 0; p[i] != '\0' && i < UT_HOSTSIZE256; i++)
50
←
Loop condition is true.  Entering loop body→
301			if (p[i] == ':') {
51
←
Taking false branch→
302				x = &p[i];
303				*x++ = '\0';
304				break;
305			}
306		if (!nflag51.1
'nflag' is not equal to 0
 && inet_aton(p, &addr) &&
307		    (hp = gethostbyaddr((char *)&addr, sizeof(addr), AF_INET2))) {
308			if (domain[0] != '\0') {
309				p = hp->h_name;
310				p += strlen(hp->h_name);
311				p -= strlen(domain);
312				if (p > hp->h_name &&
313				    strcasecmp(p, domain) == 0)
314					*p = '\0';
315			}
316			p = hp->h_name;
317		}
318		if (x51.2
'x' is null
) {
52
←
Taking false branch→
319			(void)snprintf(buf, sizeof(buf), "%s:%.*s", p,
320			    (int)(ep->utmp.ut_host + UT_HOSTSIZE256 - x), x);
321			p = buf;
322		}
323		(void)printf("%-*.*s %-2.2s %-*.*s ",
324		    NAME_WIDTH8, UT_NAMESIZE32, ep->utmp.ut_name,
325		    strncmp(ep->utmp.ut_line, "tty", 3) ?
53
←
Assuming the condition is false→
54
←
'?' condition is false→
326		    ep->utmp.ut_line : ep->utmp.ut_line + 3,
327		    HOST_WIDTH16, HOST_WIDTH16, *p ? p : "-");
55
←
'?' condition is true→
328		pr_attime(&ep->utmp.ut_time, &now);
329		pr_idle(ep->idle);
330		pr_args(ep->kp);
56
←
Calling 'pr_args'→
331		printf("\n");
332	}
333	exit(0);
334}
335 
336static void
337fmt_putc(int c, int *leftp)
338{
339 
340	if (*leftp == 0)
341		return;
342	if (*leftp != -1)
343		*leftp -= 1;
344	putchar(c)(!__isthreaded ? __sputc(c, (&__sF[1])) : (putc)(c, (&
__sF[1])));
345}
346 
347static void
348fmt_puts(const char *s, int *leftp)
349{
350	static char *v = NULL((void *)0);
68
←
'v' initialized to a null pointer value→
351	static size_t maxlen = 0;
352	size_t len;
353 
354	if (*leftp == 0)
69
←
Assuming the condition is false→
70
←
Taking false branch→
355		return;
356	len = strlen(s) * 4 + 1;
357	if (len > maxlen) {
71
←
Assuming 'len' is <= 'maxlen'→
72
←
Taking false branch→
358		free(v);
359		maxlen = 0;
360		if (len < getpagesize())
361			len = getpagesize();
362		v = malloc(len);
363		if (v == NULL((void *)0))
364			return;
365		maxlen = len;
366	}
367	strvis(v, s, VIS_TAB0x08 | VIS_NL0x10 | VIS_CSTYLE0x02);
368	if (*leftp != -1) {
73
←
Assuming the condition is true→
74
←
Taking true branch→
369		len = strlen(v);
75
←
Null pointer passed as 1st argument to string length function
370		if (len > *leftp) {
371			v[*leftp] = '\0';
372			*leftp = 0;
373		} else
374			*leftp -= len;
375	}
376	printf("%s", v);
377}
378 
379 
380static void
381pr_args(struct kinfo_proc *kp)
382{
383	char **argv, *str;
384	int left;
385 
386	if (kp == NULL((void *)0))
57
←
Assuming 'kp' is not equal to NULL→
58
←
Taking false branch→
387		goto nothing;		/* no matching process found */
388	left = argwidth;
389	argv = kvm_getargv(kd, kp, argwidth+60);  /* +60 for ftpd snip */
390	if (argv == NULL((void *)0))
59
←
Assuming 'argv' is not equal to NULL→
60
←
Taking false branch→
391		goto nothing;
392 
393	if (*argv == NULL((void *)0) || **argv == '\0') {
61
←
Assuming the condition is false→
62
←
Assuming the condition is false→
63
←
Taking false branch→
394		/* Process has zeroed argv[0], display executable name. */
395		fmt_putc('(', &left);
396		fmt_puts(kp->p_comm, &left);
397		fmt_putc(')', &left);
398	}
399	while (*argv) {
64
←
Loop condition is true.  Entering loop body→
400		/*
401		 * ftp argv[0] is in the following format:
402		 * ftpd: HOSTNAME: [USER/PASS: ]CMD args (ftpd)
403		 */
404		if (strncmp(*argv, "ftpd:", 5) == 0) {
65
←
Assuming the condition is false→
66
←
Taking false branch→
405			if ((str = strchr(*argv + 5, ':')) != NULL((void *)0))
406				str = strchr(str + 1, ':');
407			if (str != NULL((void *)0)) {
408				if ((str[0] == ':') &&
409				    isspace((unsigned char)str[1]))
410					str += 2;
411				fmt_puts(str, &left);
412			} else
413				fmt_puts(*argv, &left);
414		} else
415			fmt_puts(*argv, &left);
67
←
Calling 'fmt_puts'→
416		argv++;
417		fmt_putc(' ', &left);
418	}
419	return;
420nothing:
421	putchar('-')(!__isthreaded ? __sputc('-', (&__sF[1])) : (putc)('-', (
&__sF[1])));
422}
423 
424static void
425pr_header(time_t *nowp, int nusers)
426{
427	double avenrun[3];
428	struct timespec boottime;
429	time_t uptime;
430	int days, hrs, i, mins;
431	char buf[256];
432 
433	/*
434	 * Print time of day.
435	 */
436	(void)strftime(buf, sizeof(buf) - 1, "%l:%M%p", localtime(nowp));
437	buf[sizeof(buf) - 1] = '\0';
438	(void)printf("%s ", buf);
439 
440	/*
441	 * Print how long system has been up.
442	 */
443	if (clock_gettime(CLOCK_BOOTTIME6, &boottime) != -1) {
444		uptime = boottime.tv_sec;
445		if (uptime > 59) {
446			uptime += 30;
447			days = uptime / SECSPERDAY(24 * 60 * 60);
448			uptime %= SECSPERDAY(24 * 60 * 60);
449			hrs = uptime / SECSPERHOUR(60 * 60);
450			uptime %= SECSPERHOUR(60 * 60);
451			mins = uptime / 60;
452			(void)printf(" up");
453			if (days > 0)
454				(void)printf(" %d day%s,", days,
455				    days > 1 ? "s" : "");
456			if (hrs > 0 && mins > 0)
457				(void)printf(" %2d:%02d,", hrs, mins);
458			else {
459				if (hrs > 0)
460					(void)printf(" %d hr%s,",
461					    hrs, hrs > 1 ? "s" : "");
462				if (mins > 0 || (days == 0 && hrs == 0))
463					(void)printf(" %d min%s,",
464					    mins, mins != 1 ? "s" : "");
465			}
466		} else
467			printf(" %d secs,", (int)uptime);
468	}
469 
470	/* Print number of users logged in to system */
471	(void)printf(" %d user%s", nusers, nusers != 1 ? "s" : "");
472 
473	/*
474	 * Print 1, 5, and 15 minute load averages.
475	 */
476	if (getloadavg(avenrun, sizeof(avenrun) / sizeof(avenrun[0])) == -1)
477		(void)printf(", no load average information available\n");
478	else {
479		(void)printf(", load averages:");
480		for (i = 0; i < (sizeof(avenrun) / sizeof(avenrun[0])); i++) {
481			if (i > 0)
482				(void)printf(",");
483			(void)printf(" %.2f", avenrun[i]);
484		}
485		(void)printf("\n");
486	}
487}
488 
489static struct stat *
490ttystat(char *line)
491{
492	static struct stat sb;
493	char ttybuf[sizeof(_PATH_DEV"/dev/") + UT_LINESIZE8];
494 
495	/* Note, line may not be NUL-terminated */
496	(void)strlcpy(ttybuf, _PATH_DEV"/dev/", sizeof(ttybuf));
497	(void)strncat(ttybuf, line, sizeof(ttybuf) - 1 - strlen(ttybuf));
498	if (stat(ttybuf, &sb))
499		return (NULL((void *)0));
500	return (&sb);
501}
502 
503static void
504usage(int wcmd)
505{
506	if (wcmd)
507		(void)fprintf(stderr(&__sF[2]),
508		    "usage: w [-ahi] [-M core] [-N system] [user]\n");
509	else
510		(void)fprintf(stderr(&__sF[2]),
511		    "usage: uptime\n");
512	exit (1);
513}