xref: /illumos-gate/usr/src/cmd/ptools/ptree/ptree.c (revision 21ca3fa0977dd3ad21d619522ac5e57d35b022b1)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  * Copyright 2019 Joyent, Inc.
25  */
26 
27 /*
28  * ptree -- print family tree of processes
29  */
30 
31 #include <assert.h>
32 #include <stdio.h>
33 #include <string.h>
34 #include <errno.h>
35 #include <err.h>
36 #include <fcntl.h>
37 #include <sys/debug.h>
38 #include <sys/types.h>
39 #include <sys/termios.h>
40 #include <unistd.h>
41 #include <stdlib.h>
42 #include <dirent.h>
43 #include <pwd.h>
44 #include <libproc.h>
45 #include <libzonecfg.h>
46 #include <limits.h>
47 #include <libcontract.h>
48 #include <locale.h>
49 #include <langinfo.h>
50 #include <sys/contract.h>
51 #include <sys/ctfs.h>
52 #include <libcontract_priv.h>
53 #include <sys/stat.h>
54 #include <stdbool.h>
55 
56 #define	COLUMN_DEFAULT	80
57 #define	CHUNK_SIZE	256 /* Arbitrary amount */
58 #define	FAKEDPID0(p)	(p->pid == 0 && p->psargs[0] == '\0')
59 #define	HAS_SIBLING(p)	((p)->sp != NULL && (p)->sp->done != 0)
60 
61 typedef struct ps {
62 	int	done;
63 	uid_t	uid;
64 	uid_t	gid;
65 	pid_t	pid;		/* pid == -1 indicates this is a contract */
66 	pid_t	ppid;
67 	pid_t	pgrp;
68 	pid_t	sid;
69 	zoneid_t zoneid;
70 	ctid_t	ctid;
71 	char *svc_fmri;
72 	timestruc_t start;
73 	char	psargs[PRARGSZ];
74 	struct ps *pp;		/* parent */
75 	struct ps *sp;		/* sibling */
76 	struct ps *cp;		/* child */
77 } ps_t;
78 
79 enum { DASH = 0, BAR, CORNER, VRIGHT };
80 
81 static	ps_t	**ps;		/* array of ps_t's */
82 static	unsigned psize;		/* size of array */
83 static	int	nps;		/* number of ps_t's */
84 static	ps_t	**ctps;		/* array of contract ps_t's */
85 static	unsigned ctsize;	/* size of contract array */
86 static	int	nctps;		/* number of contract ps_t's */
87 static	ps_t	*proc0;		/* process 0 */
88 static	ps_t	*proc1;		/* process 1 */
89 
90 static	int	aflag = 0;
91 static	int	cflag = 0;
92 static	int	gflag = 0;
93 static	int	sflag = 0;
94 static	int	wflag = 0;
95 static	int	zflag = 0;
96 static	zoneid_t zoneid;
97 static	char *match_svc;
98 static	char *match_inst;
99 static	int	columns;
100 
101 static const char *box_ascii[] = {
102 	[DASH] =	"-",
103 	[BAR] =		"|",
104 	[CORNER] =	"`",
105 	[VRIGHT] =	"+"
106 };
107 
108 static const char *box_utf8[] = {
109 	[DASH] =	"\xe2\x94\x80", /* \u2500 */
110 	[BAR] =		"\xe2\x94\x82", /* \u2502 */
111 	[CORNER] =	"\xe2\x94\x94", /* \u2514 */
112 	[VRIGHT] =	"\xe2\x94\x9c", /* \u251c */
113 };
114 
115 static const char **box;
116 
117 static size_t get_termwidth(void);
118 static const char **get_boxchars(void);
119 static int add_proc(psinfo_t *, lwpsinfo_t *, void *);
120 static bool match_proc(ps_t *);
121 static void markprocs(ps_t *);
122 static int printone(ps_t *, int);
123 static void insertchild(ps_t *, ps_t *);
124 static void prsort(ps_t *);
125 static void printsubtree(ps_t *, int);
126 static void p_get_svc_fmri(ps_t *, ct_stathdl_t);
127 static char *parse_svc(const char *, char **);
128 static zoneid_t getzone(const char *);
129 static ps_t *fakepid0(void);
130 
131 static void *zalloc(size_t);
132 static void *xreallocarray(void *, size_t, size_t);
133 static char *xstrdup(const char *);
134 
135 static void __NORETURN
usage(void)136 usage(void)
137 {
138 	(void) fprintf(stderr,
139 	    "usage:\t%s [-ac] [-s svc] [-z zone] [ {pid|user} ... ]\n",
140 	    getprogname());
141 	(void) fprintf(stderr,
142 	    "  (show process trees)\n");
143 	(void) fprintf(stderr,
144 	    "  list can include process-ids and user names\n");
145 	(void) fprintf(stderr,
146 	    "  -a : include children of process 0\n");
147 	(void) fprintf(stderr,
148 	    "  -c : show contracts\n");
149 	(void) fprintf(stderr,
150 	    "  -g : use line drawing characters in output\n");
151 	(void) fprintf(stderr,
152 	    "  -s : print only processes with given service FMRI\n");
153 	(void) fprintf(stderr,
154 	    "  -w : allow lines to wrap instead of truncating\n");
155 	(void) fprintf(stderr,
156 	    "  -z : print only processes in given zone\n");
157 	exit(2);
158 }
159 
160 int
main(int argc,char ** argv)161 main(int argc, char **argv)
162 {
163 	int opt;
164 	int errflg = 0;
165 	int n;
166 	int retc = 0;
167 
168 	ps_t *p;
169 
170 	/* options */
171 	while ((opt = getopt(argc, argv, "acgs:wz:")) != EOF) {
172 		switch (opt) {
173 		case 'a':		/* include children of process 0 */
174 			aflag = 1;
175 			break;
176 		case 'c':		/* display contract ownership */
177 			aflag = cflag = 1;
178 			break;
179 		case 'g':
180 			gflag = 1;
181 			box = get_boxchars();
182 			break;
183 		case 's':
184 			sflag = 1;
185 			match_svc = parse_svc(optarg, &match_inst);
186 			break;
187 		case 'w':
188 			wflag = 1;
189 			break;
190 		case 'z':		/* only processes in given zone */
191 			zflag = 1;
192 			zoneid = getzone(optarg);
193 			break;
194 		default:
195 			errflg = 1;
196 			break;
197 		}
198 	}
199 
200 	argc -= optind;
201 	argv += optind;
202 
203 	if (errflg)
204 		usage();
205 
206 	if (!wflag) {
207 		columns = get_termwidth();
208 		VERIFY3S(columns, >, 0);
209 	}
210 
211 	nps = 0;
212 	psize = 0;
213 	ps = NULL;
214 
215 	/* Currently, this can only fail if the 3rd argument is invalid */
216 	VERIFY0(proc_walk(add_proc, NULL, PR_WALK_PROC|PR_WALK_INCLUDE_SYS));
217 
218 	if (proc0 == NULL)
219 		proc0 = fakepid0();
220 	if (proc1 == NULL)
221 		proc1 = proc0;
222 
223 	for (n = 0; n < nps; n++) {
224 		p = ps[n];
225 		if (p->pp == NULL)
226 			prsort(p);
227 	}
228 
229 	if (cflag)
230 		/* Parent all orphan contracts to process 0. */
231 		for (n = 0; n < nctps; n++) {
232 			p = ctps[n];
233 			if (p->pp == NULL)
234 				insertchild(proc0, p);
235 		}
236 
237 	if (argc == 0) {
238 		for (p = aflag ? proc0->cp : proc1->cp; p != NULL; p = p->sp) {
239 			markprocs(p);
240 			printsubtree(p, 0);
241 		}
242 		return (0);
243 	}
244 
245 	/*
246 	 * Initially, assume we're not going to find any processes.  If we do
247 	 * mark any, then set this to 0 to indicate no error.
248 	 */
249 	errflg = 1;
250 
251 	while (argc-- > 0) {
252 		char *arg;
253 		char *next;
254 		pid_t pid;
255 		uid_t uid;
256 		int n;
257 
258 		/* in case some silly person said 'ptree /proc/[0-9]*' */
259 		arg = strrchr(*argv, '/');
260 		if (arg++ == NULL)
261 			arg = *argv;
262 		argv++;
263 		uid = (uid_t)-1;
264 		errno = 0;
265 		pid = strtoul(arg, &next, 10);
266 		if (errno != 0 || *next != '\0') {
267 			struct passwd *pw = getpwnam(arg);
268 			if (pw == NULL) {
269 				warnx("invalid username: %s", arg);
270 				retc = 1;
271 				continue;
272 			}
273 			uid = pw->pw_uid;
274 			pid = -1;
275 		}
276 
277 		for (n = 0; n < nps; n++) {
278 			ps_t *p = ps[n];
279 
280 			/*
281 			 * A match on pid causes the subtree starting at pid
282 			 * to be printed, regardless of the -a flag.
283 			 * For uid matches, we never include pid 0 and only
284 			 * include the children of pid 0 if -a was specified.
285 			 */
286 			if (p->pid == pid || (p->uid == uid && p->pid != 0 &&
287 			    (p->ppid != 0 || aflag))) {
288 				errflg = 0;
289 				markprocs(p);
290 				if (p->pid != 0)
291 					for (p = p->pp; p != NULL &&
292 					    p->done != 1 && p->pid != 0;
293 					    p = p->pp)
294 						if ((p->ppid != 0 || aflag) &&
295 						    match_proc(p))
296 							p->done = 1;
297 				if (uid == (uid_t)-1)
298 					break;
299 			}
300 		}
301 	}
302 
303 	printsubtree(proc0, 0);
304 	/*
305 	 * retc = 1 if an invalid username was supplied.
306 	 * errflg = 1 if no matching processes were found.
307 	 */
308 	return (retc || errflg);
309 }
310 
311 
312 #define	PIDWIDTH	6
313 
314 static void
printlines(ps_t * p,int level)315 printlines(ps_t *p, int level)
316 {
317 	if (level == 0)
318 		return;
319 
320 	if (!gflag) {
321 		(void) printf("%*s", level * 2, "");
322 		return;
323 	}
324 
325 	for (int i = 1; i < level; i++) {
326 		ps_t *ancestor = p;
327 
328 		/* Find our ancestor at depth 'i' */
329 		for (int j = i; j < level; j++)
330 			ancestor = ancestor->pp;
331 
332 		(void) printf("%s ", HAS_SIBLING(ancestor) ? box[BAR] : " ");
333 	}
334 
335 	(void) printf("%s%s", HAS_SIBLING(p) ? box[VRIGHT] : box[CORNER],
336 	    box[DASH]);
337 }
338 
339 static int
printone(ps_t * p,int level)340 printone(ps_t *p, int level)
341 {
342 	int n, indent;
343 
344 	if (p->done && !FAKEDPID0(p)) {
345 		indent = level * 2;
346 
347 		if (wflag) {
348 			n = strlen(p->psargs);
349 		} else {
350 			if ((n = columns - PIDWIDTH - indent - 2) < 0)
351 				n = 0;
352 		}
353 
354 		printlines(p, level);
355 		if (p->pid >= 0) {
356 			(void) printf("%-*d %.*s\n", PIDWIDTH, (int)p->pid, n,
357 			    p->psargs);
358 		} else {
359 			assert(cflag != 0);
360 			(void) printf("[process contract %d: %s]\n",
361 			    (int)p->ctid,
362 			    p->svc_fmri == NULL ? "?" : p->svc_fmri);
363 		}
364 		return (1);
365 	}
366 	return (0);
367 }
368 
369 static void
insertchild(ps_t * pp,ps_t * cp)370 insertchild(ps_t *pp, ps_t *cp)
371 {
372 	/* insert as child process of p */
373 	ps_t **here;
374 	ps_t *sp;
375 
376 	/* sort by start time */
377 	for (here = &pp->cp, sp = pp->cp;
378 	    sp != NULL;
379 	    here = &sp->sp, sp = sp->sp) {
380 		if (cp->start.tv_sec < sp->start.tv_sec)
381 			break;
382 		if (cp->start.tv_sec == sp->start.tv_sec &&
383 		    cp->start.tv_nsec < sp->start.tv_nsec)
384 			break;
385 	}
386 	cp->pp = pp;
387 	cp->sp = sp;
388 	*here = cp;
389 }
390 
391 static ct_stathdl_t
ct_status_open(ctid_t ctid,struct stat64 * stp)392 ct_status_open(ctid_t ctid, struct stat64 *stp)
393 {
394 	ct_stathdl_t hdl;
395 	int fd;
396 
397 	if ((fd = contract_open(ctid, "process", "status", O_RDONLY)) == -1)
398 		return (NULL);
399 
400 	if (fstat64(fd, stp) == -1 || ct_status_read(fd, CTD_FIXED, &hdl)) {
401 		(void) close(fd);
402 		return (NULL);
403 	}
404 
405 	(void) close(fd);
406 
407 	return (hdl);
408 }
409 
410 /*
411  * strdup() failure is OK - better to report something than fail totally.
412  */
413 static void
p_get_svc_fmri(ps_t * p,ct_stathdl_t inhdl)414 p_get_svc_fmri(ps_t *p, ct_stathdl_t inhdl)
415 {
416 	ct_stathdl_t hdl = inhdl;
417 	struct stat64 st;
418 	char *fmri;
419 
420 	if (hdl == NULL && (hdl = ct_status_open(p->ctid, &st)) == NULL)
421 		return;
422 
423 	if (ct_pr_status_get_svc_fmri(hdl, &fmri) == 0)
424 		p->svc_fmri = strdup(fmri);
425 
426 	if (inhdl == NULL)
427 		ct_status_free(hdl);
428 }
429 
430 static void
ctsort(ctid_t ctid,ps_t * p)431 ctsort(ctid_t ctid, ps_t *p)
432 {
433 	ps_t *pp;
434 	int n;
435 	ct_stathdl_t hdl;
436 	struct stat64 st;
437 
438 	for (n = 0; n < nctps; n++)
439 		if (ctps[n]->ctid == ctid) {
440 			insertchild(ctps[n], p);
441 			return;
442 		}
443 
444 	if ((hdl = ct_status_open(ctid, &st)) == NULL)
445 		return;
446 
447 	if (nctps >= ctsize) {
448 		ctsize += CHUNK_SIZE;
449 		ctps = xreallocarray(ctps, ctsize, sizeof (ps_t *));
450 	}
451 	pp = zalloc(sizeof (*pp));
452 	ctps[nctps++] = pp;
453 
454 	pp->pid = -1;
455 	pp->ctid = ctid;
456 
457 	p_get_svc_fmri(pp, hdl);
458 
459 	pp->start.tv_sec = st.st_ctime;
460 	insertchild(pp, p);
461 
462 	pp->zoneid = ct_status_get_zoneid(hdl);
463 
464 	/*
465 	 * In a zlogin <zonename>, the contract belongs to the
466 	 * global zone and the shell opened belongs to <zonename>.
467 	 * If the -c and -z zonename flags are used together, then
468 	 * we need to adjust the zoneid in the contract's ps_t as
469 	 * follows:
470 	 *
471 	 * ptree -c -z <zonename> --> zoneid == p->zoneid
472 	 * ptree -c -z global	  --> zoneid == pp->zoneid
473 	 *
474 	 * The approach assumes that no tool can create processes in
475 	 * different zones under the same contract. If this is
476 	 * possible, ptree will need to refactor how it builds
477 	 * its internal tree of ps_t's
478 	 */
479 	if (zflag && p->zoneid != pp->zoneid &&
480 	    (zoneid == p->zoneid || zoneid == pp->zoneid))
481 		pp->zoneid = p->zoneid;
482 	if (ct_status_get_state(hdl) == CTS_OWNED) {
483 		pp->ppid = ct_status_get_holder(hdl);
484 		prsort(pp);
485 	} else if (ct_status_get_state(hdl) == CTS_INHERITED) {
486 		ctsort(ct_status_get_holder(hdl), pp);
487 	}
488 	ct_status_free(hdl);
489 }
490 
491 static void
prsort(ps_t * p)492 prsort(ps_t *p)
493 {
494 	int n;
495 	ps_t *pp;
496 
497 	/* If this node already has a parent, it's sorted */
498 	if (p->pp != NULL)
499 		return;
500 
501 	for (n = 0; n < nps; n++) {
502 		pp = ps[n];
503 
504 		if (pp != NULL && p != pp && p->ppid == pp->pid) {
505 			if (cflag && p->pid >= 0 &&
506 			    p->ctid != -1 && p->ctid != pp->ctid) {
507 				ctsort(p->ctid, p);
508 			} else {
509 				insertchild(pp, p);
510 				prsort(pp);
511 			}
512 			return;
513 		}
514 	}
515 
516 	/* File parentless processes under their contracts */
517 	if (cflag && p->pid >= 0)
518 		ctsort(p->ctid, p);
519 }
520 
521 static void
printsubtree(ps_t * p,int level)522 printsubtree(ps_t *p, int level)
523 {
524 	int printed;
525 
526 	printed = printone(p, level);
527 	if (level != 0 || printed == 1)
528 		level++;
529 	for (p = p->cp; p != NULL; p = p->sp)
530 		printsubtree(p, level);
531 }
532 
533 /*
534  * Match against the service name (and just the final component), and any
535  * specified instance name.
536  */
537 static bool
match_proc(ps_t * p)538 match_proc(ps_t *p)
539 {
540 	bool matched = false;
541 	const char *cp;
542 	char *p_inst;
543 	char *p_svc;
544 
545 	if (zflag && p->zoneid != zoneid)
546 		return (false);
547 
548 	if (!sflag)
549 		return (true);
550 
551 	if (p->svc_fmri == NULL)
552 		return (false);
553 
554 	p_svc = parse_svc(p->svc_fmri, &p_inst);
555 
556 	if (strcmp(p_svc, match_svc) != 0 &&
557 	    ((cp = strrchr(p_svc, '/')) == NULL ||
558 	    strcmp(cp + 1, match_svc) != 0)) {
559 		goto out;
560 	}
561 
562 	if (strlen(match_inst) == 0 ||
563 	    strcmp(p_inst, match_inst) == 0)
564 		matched = true;
565 
566 out:
567 	free(p_svc);
568 	free(p_inst);
569 	return (matched);
570 }
571 
572 static void
markprocs(ps_t * p)573 markprocs(ps_t *p)
574 {
575 	if (match_proc(p))
576 		p->done = 1;
577 
578 	for (p = p->cp; p != NULL; p = p->sp)
579 		markprocs(p);
580 }
581 
582 /*
583  * If there's no "top" process, we fake one; it will be the parent of
584  * all orphans.
585  */
586 static ps_t *
fakepid0(void)587 fakepid0(void)
588 {
589 	ps_t *p0, *p;
590 	int n;
591 
592 	p0 = zalloc(sizeof (*p0));
593 
594 	/* First build all partial process trees. */
595 	for (n = 0; n < nps; n++) {
596 		p = ps[n];
597 		if (p->pp == NULL)
598 			prsort(p);
599 	}
600 
601 	/* Then adopt all orphans. */
602 	for (n = 0; n < nps; n++) {
603 		p = ps[n];
604 		if (p->pp == NULL)
605 			insertchild(p0, p);
606 	}
607 
608 	/* We've made sure earlier there's room for this. */
609 	ps[nps++] = p0;
610 	return (p0);
611 }
612 
613 /* convert string containing zone name or id to a numeric id */
614 static zoneid_t
getzone(const char * arg)615 getzone(const char *arg)
616 {
617 	zoneid_t zoneid;
618 
619 	if (zone_get_id(arg, &zoneid) != 0)
620 		err(EXIT_FAILURE, "unknown zone: %s", arg);
621 
622 	return (zoneid);
623 }
624 
625 /* svc:/mysvc:default ->  mysvc, default */
626 static char *
parse_svc(const char * arg,char ** instp)627 parse_svc(const char *arg, char **instp)
628 {
629 	const char *p = arg;
630 	char *ret;
631 	char *cp;
632 
633 	if (strncmp(p, "svc:/", strlen("svc:/")) == 0)
634 		p += strlen("svc:/");
635 
636 	ret = xstrdup(p);
637 
638 	if ((cp = strrchr(ret, ':')) != NULL) {
639 		*cp = '\0';
640 		cp++;
641 	} else {
642 		cp = "";
643 	}
644 
645 	*instp = xstrdup(cp);
646 	return (ret);
647 }
648 
649 static int
add_proc(psinfo_t * info,lwpsinfo_t * lwp __unused,void * arg __unused)650 add_proc(psinfo_t *info, lwpsinfo_t *lwp __unused, void *arg __unused)
651 {
652 	ps_t *p;
653 
654 	/*
655 	 * We make sure there is always a free slot in the table
656 	 * in case we need to add a fake p0;
657 	 */
658 	if (nps + 1 >= psize) {
659 		psize += CHUNK_SIZE;
660 		ps = xreallocarray(ps, psize, sizeof (ps_t));
661 	}
662 
663 	p = zalloc(sizeof (*p));
664 	ps[nps++] = p;
665 	p->done = 0;
666 	p->uid = info->pr_uid;
667 	p->gid = info->pr_gid;
668 	p->pid = info->pr_pid;
669 	p->ppid = info->pr_ppid;
670 	p->pgrp = info->pr_pgid;
671 	p->sid = info->pr_sid;
672 	p->zoneid = info->pr_zoneid;
673 	p->ctid = info->pr_contract;
674 	p->start = info->pr_start;
675 	proc_unctrl_psinfo(info);
676 	if (info->pr_nlwp == 0)
677 		(void) strcpy(p->psargs, "<defunct>");
678 	else if (info->pr_psargs[0] == '\0')
679 		(void) strncpy(p->psargs, info->pr_fname,
680 		    sizeof (p->psargs));
681 	else
682 		(void) strncpy(p->psargs, info->pr_psargs,
683 		    sizeof (p->psargs));
684 	p->psargs[sizeof (p->psargs)-1] = '\0';
685 	p->pp = NULL;
686 	p->sp = NULL;
687 
688 	if (sflag)
689 		p_get_svc_fmri(p, NULL);
690 
691 	if (p->pid == p->ppid)
692 		proc0 = p;
693 	if (p->pid == 1)
694 		proc1 = p;
695 
696 	return (0);
697 }
698 
699 
700 static size_t
get_termwidth(void)701 get_termwidth(void)
702 {
703 	char *s;
704 
705 	if ((s = getenv("COLUMNS")) != NULL) {
706 		unsigned long n;
707 
708 		errno = 0;
709 		n = strtoul(s, NULL, 10);
710 		if (n != 0 && errno == 0) {
711 			/* Sanity check on the range */
712 			if (n > INT_MAX)
713 				n = COLUMN_DEFAULT;
714 			return (n);
715 		}
716 	}
717 
718 	struct winsize winsize;
719 
720 	if (isatty(STDOUT_FILENO) &&
721 	    ioctl(STDOUT_FILENO, TIOCGWINSZ, &winsize) == 0 &&
722 	    winsize.ws_col != 0) {
723 		return (winsize.ws_col);
724 	}
725 
726 	return (COLUMN_DEFAULT);
727 }
728 
729 static const char **
get_boxchars(void)730 get_boxchars(void)
731 {
732 	char *codeset;
733 
734 	(void) setlocale(LC_CTYPE, "");
735 
736 	codeset = nl_langinfo(CODESET);
737 
738 	/*
739 	 * Only use the UTF-8 box drawing characters if the locale uses
740 	 * the UTF-8 codeset.
741 	 */
742 	if (codeset != NULL && strcmp(codeset, "UTF-8") == 0)
743 		return (box_utf8);
744 
745 	return (box_ascii);
746 }
747 
748 static void *
zalloc(size_t len)749 zalloc(size_t len)
750 {
751 	void *p = calloc(1, len);
752 
753 	if (p == NULL)
754 		err(EXIT_FAILURE, "calloc");
755 	return (p);
756 }
757 
758 static void *
xreallocarray(void * ptr,size_t nelem,size_t elsize)759 xreallocarray(void *ptr, size_t nelem, size_t elsize)
760 {
761 	void *p = reallocarray(ptr, nelem, elsize);
762 
763 	if (p == NULL)
764 		err(EXIT_FAILURE, "reallocarray");
765 	return (p);
766 }
767 
768 static char *
xstrdup(const char * s)769 xstrdup(const char *s)
770 {
771 	char *news = strdup(s);
772 
773 	if (news == NULL)
774 		err(EXIT_FAILURE, "strdup");
775 	return (news);
776 }
777