xref: /dragonfly/bin/ps/ps.c (revision 25a2db75)
1 /*-
2  * Copyright (c) 1990, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * @(#) Copyright (c) 1990, 1993, 1994 The Regents of the University of California.  All rights reserved.
30  * @(#)ps.c	8.4 (Berkeley) 4/2/94
31  * $FreeBSD: src/bin/ps/ps.c,v 1.30.2.6 2002/07/04 08:30:37 sobomax Exp $
32  */
33 
34 #include <sys/user.h>
35 #include <sys/param.h>
36 #include <sys/time.h>
37 #include <sys/queue.h>
38 #include <sys/resource.h>
39 #include <sys/stat.h>
40 #include <sys/ioctl.h>
41 #include <sys/sysctl.h>
42 #include <sys/mount.h>
43 
44 #include <ctype.h>
45 #include <err.h>
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <kvm.h>
49 #include <limits.h>
50 #include <locale.h>
51 #include <nlist.h>
52 #include <paths.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <unistd.h>
57 #include <pwd.h>
58 #include <utmp.h>
59 
60 #include "ps.h"
61 
62 #define SEP ", \t"		/* username separators */
63 
64 #define KHSIZE	2048
65 #define KHMASK	(KHSIZE - 1)
66 
67 KINFO *KInfo;
68 KINFO **KSort;
69 struct varent *vhead, *vtail;
70 
71 int	eval;			/* exit value */
72 int	cflag;			/* -c */
73 int	rawcpu;			/* -C */
74 int	sumrusage;		/* -S */
75 int	termwidth;		/* width of screen (0 == infinity) */
76 int	totwidth;		/* calculated width of requested variables */
77 int	numcpus;		/* hw.ncpu */
78 
79 static int needuser, needcomm, needenv;
80 #if defined(LAZY_PS)
81 static int forceuread=0;
82 #define PS_ARGS	"aCcefgHhjLlM:mN:O:o:p:rRSTt:U:uvwx"
83 #else
84 static int forceuread=1;
85 #define PS_ARGS	"aCcegHhjLlM:mN:O:o:p:rRSTt:U:uvwx"
86 #endif
87 
88 enum sort { DEFAULT, SORTMEM, SORTCPU } sortby = DEFAULT;
89 
90 static const char *getfmt (char **(*)(kvm_t *, const struct kinfo_proc *, int),
91 		    KINFO *, char *, int);
92 static char	*kludge_oldps_options (char *);
93 static int	 pscomp (const void *, const void *);
94 static void	 dochain (KINFO **ksort, int nentries);
95 static void	 saveuser (KINFO *);
96 static void	 scanvars (void);
97 static void	 dynsizevars (KINFO *);
98 static void	 sizevars (void);
99 static int	 check_procfs(void);
100 static void	 usage (void);
101 static uid_t	*getuids(const char *, int *);
102 
103 struct timeval btime;
104 
105 static char dfmt[] = "pid tt state time command";
106 static char jfmt[] = "user pid ppid pgid sess jobc state tt time command";
107 static char lfmt[] = "uid pid ppid cpu pri nice vsz rss wchan state tt time command";
108 static char   o1[] = "pid";
109 static char   o2[] = "tt state time command";
110 static char ufmt[] = "user pid %cpu %mem vsz rss tt state start time command";
111 static char vfmt[] = "pid state time sl re pagein vsz rss lim tsiz %cpu %mem command";
112 
113 kvm_t *kd;
114 
115 int
116 main(int argc, char **argv)
117 {
118 	struct kinfo_proc *kp;
119 	struct varent *vent;
120 	struct winsize ws;
121 	dev_t ttydev;
122 	pid_t pid;
123 	uid_t *uids;
124 	int all, ch, flag, i, fmt, ofmt, lineno, nentries, nocludge, dropgid;
125 	int prtheader, wflag, what, xflg, uid, nuids, showtid;
126 	int chainflg;
127 	char errbuf[_POSIX2_LINE_MAX];
128 	const char *cp, *nlistf, *memf;
129 	size_t btime_size = sizeof(struct timeval);
130 	size_t numcpus_size = sizeof(numcpus);
131 
132 	setlocale(LC_ALL, "");
133 
134 	if ((ioctl(STDOUT_FILENO, TIOCGWINSZ, (char *)&ws) == -1 &&
135 	     ioctl(STDERR_FILENO, TIOCGWINSZ, (char *)&ws) == -1 &&
136 	     ioctl(STDIN_FILENO,  TIOCGWINSZ, (char *)&ws) == -1) ||
137 	     ws.ws_col == 0)
138 		termwidth = 79;
139 	else
140 		termwidth = ws.ws_col - 1;
141 
142 	/*
143 	 * Don't apply a kludge if the first argument is an option taking an
144 	 * argument
145 	 */
146 	if (argc > 1) {
147 		nocludge = 0;
148 		if (argv[1][0] == '-') {
149 			for (cp = PS_ARGS; *cp != '\0'; cp++) {
150 				if (*cp != ':')
151 					continue;
152 				if (*(cp - 1) == argv[1][1]) {
153 					nocludge = 1;
154 					break;
155 				}
156 			}
157 		}
158 		if (nocludge == 0)
159 			argv[1] = kludge_oldps_options(argv[1]);
160 	}
161 
162 	all = fmt = ofmt = prtheader = wflag = xflg = showtid = 0;
163 	chainflg = 0;
164 	pid = -1;
165 	nuids = 0;
166 	uids = NULL;
167 	ttydev = NODEV;
168 	dropgid = 0;
169 	memf = nlistf = _PATH_DEVNULL;
170 
171 	while ((ch = getopt(argc, argv, PS_ARGS)) != -1)
172 		switch((char)ch) {
173 		case 'a':
174 			all = 1;
175 			break;
176 		case 'C':
177 			rawcpu = 1;
178 			break;
179 		case 'c':
180 			cflag = 1;
181 			break;
182 		case 'e':			/* XXX set ufmt */
183 			needenv = 1;
184 			break;
185 		case 'g':
186 			break;			/* no-op */
187 		case 'H':
188 			showtid = KERN_PROC_FLAG_LWP;
189 			break;
190 		case 'h':
191 			prtheader = ws.ws_row > 5 ? ws.ws_row : 22;
192 			break;
193 		case 'j':
194 			parsefmt(jfmt);
195 			fmt = 1;
196 			jfmt[0] = '\0';
197 			break;
198 		case 'L':
199 			showkey();
200 			exit(0);
201 		case 'l':
202 			parsefmt(lfmt);
203 			fmt = 1;
204 			lfmt[0] = '\0';
205 			break;
206 		case 'M':
207 			memf = optarg;
208 			dropgid = 1;
209 			break;
210 		case 'm':
211 			sortby = SORTMEM;
212 			break;
213 		case 'N':
214 			nlistf = optarg;
215 			dropgid = 1;
216 			break;
217 		case 'O':
218 			parsefmt(o1);
219 			parsefmt(optarg);
220 			parsefmt(o2);
221 			o1[0] = o2[0] = '\0';
222 			fmt = 1;
223 			break;
224 		case 'o':
225 			parsefmt(optarg);
226 			fmt = ofmt = 1;
227 			break;
228 #if defined(LAZY_PS)
229 		case 'f':
230 			if (getuid() == 0 || getgid() == 0)
231 			    forceuread = 1;
232 			break;
233 #endif
234 		case 'p':
235 			pid = atol(optarg);
236 			xflg = 1;
237 			break;
238 		case 'r':
239 			sortby = SORTCPU;
240 			break;
241 		case 'R':
242 			chainflg = 1;
243 			break;
244 		case 'S':
245 			sumrusage = 1;
246 			break;
247 		case 'T':
248 			if ((optarg = ttyname(STDIN_FILENO)) == NULL)
249 				errx(1, "stdin: not a terminal");
250 			/* FALLTHROUGH */
251 		case 't': {
252 			struct stat sb;
253 			char pathbuf[PATH_MAX];
254 			const char *ttypath;
255 
256 			if (strcmp(optarg, "co") == 0) {
257 				ttypath = _PATH_CONSOLE;
258 			} else if (*optarg >= '0' && *optarg <= '9') {
259 				snprintf(pathbuf, sizeof(pathbuf),
260 					 "%spts/%s", _PATH_DEV, optarg);
261 				ttypath = pathbuf;
262 			} else if (*optarg != '/') {
263 				snprintf(pathbuf, sizeof(pathbuf),
264 					 "%s%s", _PATH_TTY, optarg);
265 				ttypath = pathbuf;
266 			} else {
267 				ttypath = optarg;
268 			}
269 			if (stat(ttypath, &sb) == -1)
270 				err(1, "%s", ttypath);
271 			if (!S_ISCHR(sb.st_mode))
272 				errx(1, "%s: not a terminal", ttypath);
273 			ttydev = sb.st_rdev;
274 			break;
275 		}
276 		case 'U':
277 			uids = getuids(optarg, &nuids);
278 			xflg++;		/* XXX: intuitive? */
279 			break;
280 		case 'u':
281 			parsefmt(ufmt);
282 			sortby = SORTCPU;
283 			fmt = 1;
284 			ufmt[0] = '\0';
285 			break;
286 		case 'v':
287 			parsefmt(vfmt);
288 			sortby = SORTMEM;
289 			fmt = 1;
290 			vfmt[0] = '\0';
291 			break;
292 		case 'w':
293 			if (wflag)
294 				termwidth = UNLIMITED;
295 			else if (termwidth < 131)
296 				termwidth = 131;
297 			wflag++;
298 			break;
299 		case 'x':
300 			xflg = 1;
301 			break;
302 		case '?':
303 		default:
304 			usage();
305 		}
306 	argc -= optind;
307 	argv += optind;
308 
309 	/*
310 	 * If the user specified ps -e then they want a copy of the process
311 	 * environment kvm_getenvv(3) attempts to open /proc/<pid>/mem.
312 	 * Check to make sure that procfs is mounted on /proc, otherwise
313 	 * print a warning informing the user that output will be incomplete.
314 	 */
315 	if (needenv == 1 && check_procfs() == 0)
316 		warnx("Process environment requires procfs(5)");
317 
318 #define	BACKWARD_COMPATIBILITY
319 #ifdef	BACKWARD_COMPATIBILITY
320 	if (*argv) {
321 		nlistf = *argv;
322 		if (*++argv) {
323 			memf = *argv;
324 		}
325 	}
326 #endif
327 	/*
328 	 * Discard setgid privileges if not the running kernel so that bad
329 	 * guys can't print interesting stuff from kernel memory.
330 	 */
331 	if (dropgid) {
332 		setgid(getgid());
333 		setuid(getuid());
334 	}
335 
336 	kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, errbuf);
337 	if (kd == NULL)
338 		errx(1, "%s", errbuf);
339 
340 	if (!fmt)
341 		parsefmt(dfmt);
342 
343 	/*
344 	 * Add TID to output format if requested unless user-specific format
345 	 * selected.
346 	 */
347 	if (showtid && !ofmt)
348 		insert_tid_in_fmt();
349 
350 	/* XXX - should be cleaner */
351 	if (!all && ttydev == NODEV && pid == -1 && !nuids) {
352 		if ((uids = malloc(sizeof (*uids))) == NULL)
353 			errx(1, "malloc: %s", strerror(errno));
354 		nuids = 1;
355 		*uids = getuid();
356 	}
357 
358 	/*
359 	 * scan requested variables, noting what structures are needed,
360 	 * and adjusting header widths as appropriate.
361 	 */
362 	scanvars();
363 
364 	/*
365 	 * Get boot time
366 	 */
367 	if (sysctlbyname("kern.boottime", &btime, &btime_size, NULL, 0) < 0) {
368 		perror("sysctl: kern.boottime");
369 		exit(EXIT_FAILURE);
370 	}
371 
372 	/*
373 	 * Get number of cpus
374 	 */
375 	if (sysctlbyname("hw.ncpu", &numcpus, &numcpus_size, NULL, 0) < 0)
376 		numcpus = 1;
377 
378 	/*
379 	 * get proc list
380 	 */
381 	if (nuids == 1) {
382 		what = KERN_PROC_UID;
383 		flag = *uids;
384 	} else if (ttydev != NODEV) {
385 		what = KERN_PROC_TTY;
386 		flag = ttydev;
387 	} else if (pid != -1) {
388 		what = KERN_PROC_PID;
389 		flag = pid;
390 	} else {
391 		what = KERN_PROC_ALL;
392 		flag = 0;
393 	}
394 	what |= showtid;
395 
396 	/*
397 	 * select procs
398 	 */
399 	if ((kp = kvm_getprocs(kd, what, flag, &nentries)) == NULL)
400 		errx(1, "%s", kvm_geterr(kd));
401 	if ((KInfo = calloc(nentries, sizeof(KINFO))) == NULL)
402 		err(1, NULL);
403 	if ((KSort = malloc(nentries * sizeof(KINFO *))) == NULL)
404 		err(1, NULL);
405 
406 	for (i = 0; i < nentries; ++i) {
407 		KInfo[i].ki_proc = &kp[i];
408 		KInfo[i].ki_indent = -1;
409 		KInfo[i].ki_ctailp = &KInfo[i].ki_cbase;
410 		if (needuser)
411 			saveuser(&KInfo[i]);
412 		dynsizevars(&KInfo[i]);
413 		KSort[i] = &KInfo[i];
414 	}
415 
416 	sizevars();
417 
418 	/*
419 	 * print header
420 	 */
421 	printheader();
422 	if (nentries == 0)
423 		exit(1);
424 	/*
425 	 * sort proc list
426 	 */
427 	qsort(KSort, nentries, sizeof(KINFO *), pscomp);
428 
429 	/*
430 	 * rejigger and indent children, parent(s) and children
431 	 * at each level retain the above sort characteristics.
432 	 */
433 	if (chainflg)
434 		dochain(KSort, nentries);
435 
436 	/*
437 	 * for each proc, call each variable output function.
438 	 */
439 	for (i = lineno = 0; i < nentries; i++) {
440 		if (xflg == 0 && (KI_PROC(KSort[i], tdev) == NODEV ||
441 		    (KI_PROC(KSort[i], flags) & P_CONTROLT ) == 0))
442 			continue;
443 		if (nuids > 1) {
444 			for (uid = 0; uid < nuids; uid++)
445 				if (KI_PROC(KSort[i], uid) ==
446 				    uids[uid])
447 					break;
448 			if (uid == nuids)
449 				continue;
450 		}
451 		STAILQ_FOREACH(vent, &var_head, link) {
452 			(vent->var->oproc)(KSort[i], vent);
453 			if (STAILQ_NEXT(vent, link) != NULL)
454 				putchar(' ');
455 		}
456 		putchar('\n');
457 		if (prtheader && lineno++ == prtheader - 4) {
458 			putchar('\n');
459 			printheader();
460 			lineno = 0;
461 		}
462 	}
463 	free(uids);
464 
465 	exit(eval);
466 }
467 
468 uid_t *
469 getuids(const char *arg, int *nuids)
470 {
471 	char name[UT_NAMESIZE + 1];
472 	struct passwd *pwd;
473 	uid_t *uids, *moreuids;
474 	size_t l;
475 	int alloc;
476 
477 
478 	alloc = 0;
479 	*nuids = 0;
480 	uids = NULL;
481 	for (; (l = strcspn(arg, SEP)) > 0; arg += l + strspn(arg + l, SEP)) {
482 		if (l >= sizeof name) {
483 			warnx("%.*s: name too long", (int)l, arg);
484 			continue;
485 		}
486 		strncpy(name, arg, l);
487 		name[l] = '\0';
488 		if ((pwd = getpwnam(name)) == NULL) {
489 			warnx("%s: no such user", name);
490 			continue;
491 		}
492 		if (*nuids >= alloc) {
493 			alloc = (alloc + 1) << 1;
494 			moreuids = realloc(uids, alloc * sizeof (*uids));
495 			if (moreuids == NULL) {
496 				free(uids);
497 				errx(1, "realloc: %s", strerror(errno));
498 			}
499 			uids = moreuids;
500 		}
501 		uids[(*nuids)++] = pwd->pw_uid;
502 	}
503 	endpwent();
504 
505 	if (!*nuids)
506 		errx(1, "No users specified");
507 
508 	return uids;
509 }
510 
511 static void
512 scanvars(void)
513 {
514 	struct varent *vent;
515 	const VAR *v;
516 
517 	STAILQ_FOREACH(vent, &var_head, link) {
518 		v = vent->var;
519 		if (v->flag & DSIZ) {
520 			vent->dwidth = vent->width;
521 			vent->width = 0;
522 		}
523 		if (v->flag & USER)
524 			needuser = 1;
525 		if (v->flag & COMM)
526 			needcomm = 1;
527 	}
528 }
529 
530 static void
531 dynsizevars(KINFO *ki)
532 {
533 	struct varent *vent;
534 	const VAR *v;
535 	int i;
536 
537 	STAILQ_FOREACH(vent, &var_head, link) {
538 		v = vent->var;
539 		if (!(v->flag & DSIZ))
540 			continue;
541 		i = (v->sproc)( ki);
542 		if (vent->width < i)
543 			vent->width = i;
544 		if (vent->width > vent->dwidth)
545 			vent->width = vent->dwidth;
546 	}
547 }
548 
549 static void
550 sizevars(void)
551 {
552 	struct varent *vent;
553 	int i;
554 
555 	STAILQ_FOREACH(vent, &var_head, link) {
556 		i = strlen(vent->header);
557 		if (vent->width < i)
558 			vent->width = i;
559 		totwidth += vent->width + 1;	/* +1 for space */
560 	}
561 	totwidth--;
562 }
563 
564 static const char *
565 getfmt(char **(*fn) (kvm_t *, const struct kinfo_proc *, int), KINFO *ki, char
566     *comm, int maxlen)
567 {
568 	const char *s;
569 
570 	if ((s =
571 	    fmt_argv((*fn)(kd, ki->ki_proc, termwidth), comm, maxlen)) == NULL)
572 		err(1, NULL);
573 	return (s);
574 }
575 
576 static void
577 saveuser(KINFO *ki)
578 {
579 	/*
580 	 * save arguments if needed
581 	 */
582 	if (needcomm) {
583 		ki->ki_args = getfmt(kvm_getargv, ki, KI_PROC(ki, comm),
584 		    MAXCOMLEN);
585 	} else {
586 		ki->ki_args = NULL;
587 	}
588 	if (needenv) {
589 		ki->ki_env = getfmt(kvm_getenvv, ki, NULL, 0);
590 	} else {
591 		ki->ki_env = NULL;
592 	}
593 }
594 
595 static int
596 pscomp(const void *arg_a, const void *arg_b)
597 {
598 	const KINFO *a = *(KINFO * const *)arg_a;
599 	const KINFO *b = *(KINFO * const *)arg_b;
600 	double di;
601 	segsz_t si;
602 	int i;
603 
604 #define VSIZE(k) (KI_PROC(k, vm_dsize) + KI_PROC(k, vm_ssize) + \
605 		  KI_PROC(k, vm_tsize))
606 
607 #if 0
608 	if (sortby == SORTIAC)
609 		return (KI_PROC(a)->p_usdata.bsd4.interactive - KI_PROC(b)->p_usdata.bsd4.interactive);
610 #endif
611 	if (sortby == SORTCPU) {
612 		di = getpcpu(b) - getpcpu(a);
613 		if (di < 0.0)
614 			return(-1);
615 		if (di > 0.0)
616 			return(+1);
617 		/* fall through */
618 	}
619 	if (sortby == SORTMEM) {
620 		si = VSIZE(b) - VSIZE(a);
621 		if (si < 0)
622 			return(-1);
623 		if (si > 0)
624 			return(+1);
625 		/* fall through */
626 	}
627 	i = KI_PROC(a, tdev) - KI_PROC(b, tdev);
628 	if (i == 0)
629 		i = KI_PROC(a, pid) - KI_PROC(b, pid);
630 	return (i);
631 }
632 
633 /*
634  * Chain (-R) option.  Sub-sorts by parent/child association.
635  */
636 static int dochain_final(KINFO **kfinal, KINFO *base, int j);
637 
638 static void
639 dochain (KINFO **ksort, int nentries)
640 {
641 	int i;
642 	int j;
643 	int hi;
644 	pid_t ppid;
645 	KINFO *scan;
646 	KINFO **khash;
647 	KINFO **kfinal;
648 
649 	/*
650 	 * First hash all the pids so we can quickly locate the
651 	 * parent pids.
652 	 */
653 	khash = calloc(KHSIZE, sizeof(KINFO *));
654 	kfinal = calloc(nentries, sizeof(KINFO *));
655 
656 	for (i = 0; i < nentries; ++i) {
657 		hi = KI_PROC(ksort[i], pid) & KHMASK;
658 
659 		ksort[i]->ki_hnext = khash[hi];
660 		khash[hi] = ksort[i];
661 	}
662 
663 	/*
664 	 * Now run through the list and create the parent associations.
665 	 */
666 	for (i = 0; i < nentries; ++i) {
667 		ppid = KI_PROC(ksort[i], ppid);
668 
669 		if (ppid <= 0 || KI_PROC(ksort[i], pid) <= 0) {
670 			scan = NULL;
671 		} else {
672 			for (scan = khash[ppid & KHMASK];
673 			     scan;
674 			     scan = scan->ki_hnext) {
675 				if (ppid == KI_PROC(scan, pid))
676 					break;
677 			}
678 		}
679 		if (scan) {
680 			ksort[i]->ki_parent = scan;
681 			*scan->ki_ctailp = ksort[i];
682 			scan->ki_ctailp = &ksort[i]->ki_cnext;
683 		}
684 	}
685 
686 	/*
687 	 * Now regenerate the list starting at root entries, then copyback.
688 	 */
689 	for (i = j = 0; i < nentries; ++i) {
690 		if (ksort[i]->ki_parent == NULL) {
691 			ksort[i]->ki_indent = 0;
692 			j = dochain_final(kfinal, ksort[i], j);
693 		}
694 	}
695 	if (i != j)
696 		errx(1, "dochain failed");
697 
698 	bcopy(kfinal, ksort, nentries * sizeof(kfinal[0]));
699 	free(kfinal);
700 	free(khash);
701 }
702 
703 static int
704 dochain_final(KINFO **kfinal, KINFO *base, int j)
705 {
706 	KINFO *scan;
707 
708 	kfinal[j++] = base;
709 	for (scan = base->ki_cbase; scan; scan = scan->ki_cnext) {
710 		/*
711 		 * Don't let us loop
712 		 */
713 		if (scan->ki_indent >= 0)
714 			continue;
715 		scan->ki_indent = base->ki_indent + 1;
716 		j = dochain_final(kfinal, scan, j);
717 	}
718 	return (j);
719 }
720 
721 /*
722  * ICK (all for getopt), would rather hide the ugliness
723  * here than taint the main code.
724  *
725  *  ps foo -> ps -foo
726  *  ps 34 -> ps -p34
727  *
728  * The old convention that 't' with no trailing tty arg means the users
729  * tty, is only supported if argv[1] doesn't begin with a '-'.  This same
730  * feature is available with the option 'T', which takes no argument.
731  */
732 static char *
733 kludge_oldps_options(char *s)
734 {
735 	size_t len;
736 	char *newopts, *ns, *cp;
737 
738 	len = strlen(s);
739 	if ((newopts = ns = malloc(len + 2)) == NULL)
740 		err(1, NULL);
741 	/*
742 	 * options begin with '-'
743 	 */
744 	if (*s != '-')
745 		*ns++ = '-';	/* add option flag */
746 	/*
747 	 * gaze to end of argv[1]
748 	 */
749 	cp = s + len - 1;
750 	/*
751 	 * if last letter is a 't' flag with no argument (in the context
752 	 * of the oldps options -- option string NOT starting with a '-' --
753 	 * then convert to 'T' (meaning *this* terminal, i.e. ttyname(0)).
754 	 *
755 	 * However, if a flag accepting a string argument is found in the
756 	 * option string, the remainder of the string is the argument to
757 	 * that flag; do not modify that argument.
758 	 */
759 	if (strcspn(s, "MNOoU") == len && *cp == 't' && *s != '-')
760 		*cp = 'T';
761 	else {
762 		/*
763 		 * otherwise check for trailing number, which *may* be a
764 		 * pid.
765 		 */
766 		while (cp >= s && isdigit(*cp))
767 			--cp;
768 	}
769 	cp++;
770 	memmove(ns, s, (size_t)(cp - s));	/* copy up to trailing number */
771 	ns += cp - s;
772 	/*
773 	 * if there's a trailing number, and not a preceding 'p' (pid) or
774 	 * 't' (tty) flag, then assume it's a pid and insert a 'p' flag.
775 	 */
776 	if (isdigit(*cp) &&
777 	    (cp == s || (cp[-1] != 't' && cp[-1] != 'p')) &&
778 	    (cp - 1 == s || cp[-2] != 't'))
779 		*ns++ = 'p';
780 	strcpy(ns, cp);		/* and append the number */
781 
782 	return (newopts);
783 }
784 
785 static int
786 check_procfs(void)
787 {
788 	struct statfs mnt;
789 
790 	if (statfs("/proc", &mnt) < 0)
791 		return (0);
792 	if (strcmp(mnt.f_fstypename, "procfs") != 0)
793 		return (0);
794 	return (1);
795 }
796 
797 static void
798 usage(void)
799 {
800 
801 	fprintf(stderr, "%s\n%s\n%s\n",
802 	    "usage: ps [-aCcefhHjlmrSTuvwx] [-M core] [-N system] [-O fmt] [-o fmt] [-p pid]",
803 	    "          [-t tty] [-U username]",
804 	    "       ps [-L]");
805 	exit(1);
806 }
807