xref: /freebsd/sbin/mdmfs/mdmfs.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2001 Dima Dorfman.
5  * 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  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 /*
30  * mdmfs (md/MFS) is a wrapper around mdconfig(8),
31  * newfs(8), and mount(8) that mimics the command line option set of
32  * the deprecated mount_mfs(8).
33  */
34 
35 #include <sys/param.h>
36 #include <sys/linker.h>
37 #include <sys/mdioctl.h>
38 #include <sys/module.h>
39 #include <sys/mount.h>
40 #include <sys/stat.h>
41 #include <sys/wait.h>
42 
43 #include <assert.h>
44 #include <err.h>
45 #include <errno.h>
46 #include <fcntl.h>
47 #include <grp.h>
48 #include <inttypes.h>
49 #include <paths.h>
50 #include <pwd.h>
51 #include <stdarg.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <ctype.h>
56 #include <unistd.h>
57 
58 typedef enum { false, true } bool;
59 
60 struct mtpt_info {
61 	uid_t		 mi_uid;
62 	bool		 mi_have_uid;
63 	gid_t		 mi_gid;
64 	bool		 mi_have_gid;
65 	mode_t		 mi_mode;
66 	bool		 mi_have_mode;
67 	bool		 mi_forced_pw;
68 };
69 
70 static	bool debug;		/* Emit debugging information? */
71 static	bool loudsubs;		/* Suppress output from helper programs? */
72 static	bool norun;		/* Actually run the helper programs? */
73 static	int unit;      		/* The unit we're working with. */
74 static	const char *mdname;	/* Name of memory disk device (e.g., "md"). */
75 static	const char *mdsuffix;	/* Suffix of memory disk device (e.g., ".uzip"). */
76 static	size_t mdnamelen;	/* Length of mdname. */
77 static	const char *path_mdconfig =_PATH_MDCONFIG;
78 
79 static void	 argappend(char **, const char *, ...) __printflike(2, 3);
80 static void	 debugprintf(const char *, ...) __printflike(1, 2);
81 static void	 do_mdconfig_attach(const char *, const enum md_types);
82 static void	 do_mdconfig_attach_au(const char *, const enum md_types);
83 static void	 do_mdconfig_detach(void);
84 static void	 do_mount_md(const char *, const char *);
85 static void	 do_mount_tmpfs(const char *, const char *);
86 static void	 do_mtptsetup(const char *, struct mtpt_info *);
87 static void	 do_newfs(const char *);
88 static void	 do_copy(const char *, const char *);
89 static void	 extract_ugid(const char *, struct mtpt_info *);
90 static int	 run(int *, const char *, ...) __printflike(2, 3);
91 static const char *run_exitstr(int);
92 static int	 run_exitnumber(int);
93 static void	 usage(void);
94 
95 int
96 main(int argc, char **argv)
97 {
98 	struct mtpt_info mi;		/* Mountpoint info. */
99 	intmax_t mdsize;
100 	char *mdconfig_arg, *newfs_arg,	/* Args to helper programs. */
101 	    *mount_arg;
102 	enum md_types mdtype;		/* The type of our memory disk. */
103 	bool have_mdtype, mlmac;
104 	bool detach, softdep, autounit, newfs;
105 	const char *mtpoint, *size_arg, *skel, *unitstr;
106 	char *p;
107 	int ch, idx;
108 	void *set;
109 	unsigned long ul;
110 
111 	/* Misc. initialization. */
112 	(void)memset(&mi, '\0', sizeof(mi));
113 	detach = true;
114 	softdep = true;
115 	autounit = false;
116 	mlmac = false;
117 	newfs = true;
118 	have_mdtype = false;
119 	skel = NULL;
120 	mdtype = MD_SWAP;
121 	mdname = MD_NAME;
122 	mdnamelen = strlen(mdname);
123 	mdsize = 0;
124 	/*
125 	 * Can't set these to NULL.  They may be passed to the
126 	 * respective programs without modification.  I.e., we may not
127 	 * receive any command-line options which will caused them to
128 	 * be modified.
129 	 */
130 	mdconfig_arg = strdup("");
131 	newfs_arg = strdup("");
132 	mount_arg = strdup("");
133 	size_arg = NULL;
134 
135 	/* If we were started as mount_mfs or mfs, imply -C. */
136 	if (strcmp(getprogname(), "mount_mfs") == 0 ||
137 	    strcmp(getprogname(), "mfs") == 0) {
138 		/* Make compatibility assumptions. */
139 		mi.mi_mode = 01777;
140 		mi.mi_have_mode = true;
141 	}
142 
143 	while ((ch = getopt(argc, argv,
144 	    "a:b:Cc:Dd:E:e:F:f:hi:k:LlMm:NnO:o:Pp:Ss:tT:Uv:w:X")) != -1)
145 		switch (ch) {
146 		case 'a':
147 			argappend(&newfs_arg, "-a %s", optarg);
148 			break;
149 		case 'b':
150 			argappend(&newfs_arg, "-b %s", optarg);
151 			break;
152 		case 'C':
153 			/* Ignored for compatibility. */
154 			break;
155 		case 'c':
156 			argappend(&newfs_arg, "-c %s", optarg);
157 			break;
158 		case 'D':
159 			detach = false;
160 			break;
161 		case 'd':
162 			argappend(&newfs_arg, "-d %s", optarg);
163 			break;
164 		case 'E':
165 			path_mdconfig = optarg;
166 			break;
167 		case 'e':
168 			argappend(&newfs_arg, "-e %s", optarg);
169 			break;
170 		case 'F':
171 			if (have_mdtype)
172 				usage();
173 			mdtype = MD_VNODE;
174 			have_mdtype = true;
175 			argappend(&mdconfig_arg, "-f %s", optarg);
176 			break;
177 		case 'f':
178 			argappend(&newfs_arg, "-f %s", optarg);
179 			break;
180 		case 'h':
181 			usage();
182 			break;
183 		case 'i':
184 			argappend(&newfs_arg, "-i %s", optarg);
185 			break;
186 		case 'k':
187 			skel = optarg;
188 			break;
189 		case 'L':
190 			loudsubs = true;
191 			break;
192 		case 'l':
193 			mlmac = true;
194 			argappend(&newfs_arg, "-l");
195 			break;
196 		case 'M':
197 			if (have_mdtype)
198 				usage();
199 			mdtype = MD_MALLOC;
200 			have_mdtype = true;
201 			argappend(&mdconfig_arg, "-o reserve");
202 			break;
203 		case 'm':
204 			argappend(&newfs_arg, "-m %s", optarg);
205 			break;
206 		case 'N':
207 			norun = true;
208 			break;
209 		case 'n':
210 			argappend(&newfs_arg, "-n");
211 			break;
212 		case 'O':
213 			argappend(&newfs_arg, "-o %s", optarg);
214 			break;
215 		case 'o':
216 			argappend(&mount_arg, "-o %s", optarg);
217 			break;
218 		case 'P':
219 			newfs = false;
220 			break;
221 		case 'p':
222 			if ((set = setmode(optarg)) == NULL)
223 				usage();
224 			mi.mi_mode = getmode(set, S_IRWXU | S_IRWXG | S_IRWXO);
225 			mi.mi_have_mode = true;
226 			mi.mi_forced_pw = true;
227 			free(set);
228 			break;
229 		case 'S':
230 			softdep = false;
231 			break;
232 		case 's':
233 			size_arg = optarg;
234 			break;
235 		case 't':
236 			argappend(&newfs_arg, "-t");
237 			break;
238 		case 'T':
239 			argappend(&mount_arg, "-t %s", optarg);
240 			break;
241 		case 'U':
242 			softdep = true;
243 			break;
244 		case 'v':
245 			argappend(&newfs_arg, "-O %s", optarg);
246 			break;
247 		case 'w':
248 			extract_ugid(optarg, &mi);
249 			mi.mi_forced_pw = true;
250 			break;
251 		case 'X':
252 			debug = true;
253 			break;
254 		default:
255 			usage();
256 		}
257 	argc -= optind;
258 	argv += optind;
259 	if (argc < 2)
260 		usage();
261 
262 	/*
263 	 * Historically our size arg was passed directly to mdconfig, which
264 	 * treats a number without a suffix as a count of 512-byte sectors;
265 	 * tmpfs would treat it as a count of bytes.  To get predictable
266 	 * behavior for 'auto' we document that the size always uses mdconfig
267 	 * rules.  To make that work, decode the size here so it can be passed
268 	 * to either tmpfs or mdconfig as a count of bytes.
269 	 */
270 	if (size_arg != NULL) {
271 		mdsize = (intmax_t)strtoumax(size_arg, &p, 0);
272 		if (p == size_arg || (p[0] != 0 && p[1] != 0) || mdsize < 0)
273 			errx(1, "invalid size '%s'", size_arg);
274 		switch (*p) {
275 		case 'p':
276 		case 'P':
277 			mdsize *= 1024;
278 		case 't':
279 		case 'T':
280 			mdsize *= 1024;
281 		case 'g':
282 		case 'G':
283 			mdsize *= 1024;
284 		case 'm':
285 		case 'M':
286 			mdsize *= 1024;
287 		case 'k':
288 		case 'K':
289 			mdsize *= 1024;
290 		case 'b':
291 		case 'B':
292 			break;
293 		case '\0':
294 			mdsize *= 512;
295 			break;
296 		default:
297 			errx(1, "invalid size suffix on '%s'", size_arg);
298 		}
299 	}
300 
301 	/*
302 	 * Based on the command line 'md-device' either mount a tmpfs filesystem
303 	 * or configure the md device then format and mount a filesystem on it.
304 	 * If the device is 'auto' use tmpfs if it is available and there is no
305 	 * request for multilabel MAC (which tmpfs does not support).
306 	 */
307 	unitstr = argv[0];
308 	mtpoint = argv[1];
309 
310 	if (strcmp(unitstr, "auto") == 0) {
311 		if (mlmac)
312 			idx = -1; /* Must use md for mlmac. */
313 		else if ((idx = modfind("tmpfs")) == -1)
314 			idx = kldload("tmpfs");
315 		if (idx == -1)
316 			unitstr = "md";
317 		else
318 			unitstr = "tmpfs";
319 	}
320 
321 	if (strcmp(unitstr, "tmpfs") == 0) {
322 		if (size_arg != NULL && mdsize != 0)
323 			argappend(&mount_arg, "-o size=%jd", mdsize);
324 		do_mount_tmpfs(mount_arg, mtpoint);
325 	} else {
326 		if (size_arg != NULL)
327 			argappend(&mdconfig_arg, "-s %jdB", mdsize);
328 		if (strncmp(unitstr, "/dev/", 5) == 0)
329 			unitstr += 5;
330 		if (strncmp(unitstr, mdname, mdnamelen) == 0)
331 			unitstr += mdnamelen;
332 		if (!isdigit(*unitstr)) {
333 			autounit = true;
334 			unit = -1;
335 			mdsuffix = unitstr;
336 		} else {
337 			ul = strtoul(unitstr, &p, 10);
338 			if (ul == ULONG_MAX)
339 				errx(1, "bad device unit: %s", unitstr);
340 			unit = ul;
341 			mdsuffix = p;	/* can be empty */
342 		}
343 
344 		if (!have_mdtype)
345 			mdtype = MD_SWAP;
346 		if (softdep)
347 			argappend(&newfs_arg, "-U");
348 		if (mdtype != MD_VNODE && !newfs)
349 			errx(1, "-P requires a vnode-backed disk");
350 
351 		/* Do the work. */
352 		if (detach && !autounit)
353 			do_mdconfig_detach();
354 		if (autounit)
355 			do_mdconfig_attach_au(mdconfig_arg, mdtype);
356 		else
357 			do_mdconfig_attach(mdconfig_arg, mdtype);
358 		if (newfs)
359 			do_newfs(newfs_arg);
360 		do_mount_md(mount_arg, mtpoint);
361 	}
362 
363 	do_mtptsetup(mtpoint, &mi);
364 	if (skel != NULL)
365 		do_copy(mtpoint, skel);
366 
367 	return (0);
368 }
369 
370 /*
371  * Append the expansion of 'fmt' to the buffer pointed to by '*dstp';
372  * reallocate as required.
373  */
374 static void
375 argappend(char **dstp, const char *fmt, ...)
376 {
377 	char *old, *new;
378 	va_list ap;
379 
380 	old = *dstp;
381 	assert(old != NULL);
382 
383 	va_start(ap, fmt);
384 	if (vasprintf(&new, fmt,ap) == -1)
385 		errx(1, "vasprintf");
386 	va_end(ap);
387 
388 	*dstp = new;
389 	if (asprintf(&new, "%s %s", old, new) == -1)
390 		errx(1, "asprintf");
391 	free(*dstp);
392 	free(old);
393 
394 	*dstp = new;
395 }
396 
397 /*
398  * If run-time debugging is enabled, print the expansion of 'fmt'.
399  * Otherwise, do nothing.
400  */
401 static void
402 debugprintf(const char *fmt, ...)
403 {
404 	va_list ap;
405 
406 	if (!debug)
407 		return;
408 	fprintf(stderr, "DEBUG: ");
409 	va_start(ap, fmt);
410 	vfprintf(stderr, fmt, ap);
411 	va_end(ap);
412 	fprintf(stderr, "\n");
413 	fflush(stderr);
414 }
415 
416 /*
417  * Attach a memory disk with a known unit.
418  */
419 static void
420 do_mdconfig_attach(const char *args, const enum md_types mdtype)
421 {
422 	int rv;
423 	const char *ta;		/* Type arg. */
424 
425 	switch (mdtype) {
426 	case MD_SWAP:
427 		ta = "-t swap";
428 		break;
429 	case MD_VNODE:
430 		ta = "-t vnode";
431 		break;
432 	case MD_MALLOC:
433 		ta = "-t malloc";
434 		break;
435 	default:
436 		abort();
437 	}
438 	rv = run(NULL, "%s -a %s%s -u %s%d", path_mdconfig, ta, args,
439 	    mdname, unit);
440 	if (rv)
441 		errx(1, "mdconfig (attach) exited %s %d", run_exitstr(rv),
442 		    run_exitnumber(rv));
443 }
444 
445 /*
446  * Attach a memory disk with an unknown unit; use autounit.
447  */
448 static void
449 do_mdconfig_attach_au(const char *args, const enum md_types mdtype)
450 {
451 	const char *ta;		/* Type arg. */
452 	char *linep;
453 	char linebuf[12];	/* 32-bit unit (10) + '\n' (1) + '\0' (1) */
454 	int fd;			/* Standard output of mdconfig invocation. */
455 	FILE *sfd;
456 	int rv;
457 	char *p;
458 	size_t linelen;
459 	unsigned long ul;
460 
461 	switch (mdtype) {
462 	case MD_SWAP:
463 		ta = "-t swap";
464 		break;
465 	case MD_VNODE:
466 		ta = "-t vnode";
467 		break;
468 	case MD_MALLOC:
469 		ta = "-t malloc";
470 		break;
471 	default:
472 		abort();
473 	}
474 	rv = run(&fd, "%s -a %s%s", path_mdconfig, ta, args);
475 	if (rv)
476 		errx(1, "mdconfig (attach) exited %s %d", run_exitstr(rv),
477 		    run_exitnumber(rv));
478 
479 	/* Receive the unit number. */
480 	if (norun) {	/* Since we didn't run, we can't read.  Fake it. */
481 		unit = 0;
482 		return;
483 	}
484 	sfd = fdopen(fd, "r");
485 	if (sfd == NULL)
486 		err(1, "fdopen");
487 	linep = fgetln(sfd, &linelen);
488 	/* If the output format changes, we want to know about it. */
489 	if (linep == NULL || linelen <= mdnamelen + 1 ||
490 	    linelen - mdnamelen >= sizeof(linebuf) ||
491 	    strncmp(linep, mdname, mdnamelen) != 0)
492 		errx(1, "unexpected output from mdconfig (attach)");
493 	linep += mdnamelen;
494 	linelen -= mdnamelen;
495 	/* Can't use strlcpy because linep is not NULL-terminated. */
496 	strncpy(linebuf, linep, linelen);
497 	linebuf[linelen] = '\0';
498 	ul = strtoul(linebuf, &p, 10);
499 	if (ul == ULONG_MAX || *p != '\n')
500 		errx(1, "unexpected output from mdconfig (attach)");
501 	unit = ul;
502 
503 	fclose(sfd);
504 }
505 
506 /*
507  * Detach a memory disk.
508  */
509 static void
510 do_mdconfig_detach(void)
511 {
512 	int rv;
513 
514 	rv = run(NULL, "%s -d -u %s%d", path_mdconfig, mdname, unit);
515 	if (rv && debug)	/* This is allowed to fail. */
516 		warnx("mdconfig (detach) exited %s %d (ignored)",
517 		    run_exitstr(rv), run_exitnumber(rv));
518 }
519 
520 /*
521  * Mount the configured memory disk.
522  */
523 static void
524 do_mount_md(const char *args, const char *mtpoint)
525 {
526 	int rv;
527 
528 	rv = run(NULL, "%s%s /dev/%s%d%s %s", _PATH_MOUNT, args,
529 	    mdname, unit, mdsuffix, mtpoint);
530 	if (rv)
531 		errx(1, "mount exited %s %d", run_exitstr(rv),
532 		    run_exitnumber(rv));
533 }
534 
535 /*
536  * Mount the configured tmpfs.
537  */
538 static void
539 do_mount_tmpfs(const char *args, const char *mtpoint)
540 {
541 	int rv;
542 
543 	rv = run(NULL, "%s -t tmpfs %s tmp %s", _PATH_MOUNT, args, mtpoint);
544 	if (rv)
545 		errx(1, "tmpfs mount exited %s %d", run_exitstr(rv),
546 		    run_exitnumber(rv));
547 }
548 
549 /*
550  * Various configuration of the mountpoint.  Mostly, enact 'mip'.
551  */
552 static void
553 do_mtptsetup(const char *mtpoint, struct mtpt_info *mip)
554 {
555 	struct statfs sfs;
556 
557 	if (!mip->mi_have_mode && !mip->mi_have_uid && !mip->mi_have_gid)
558 		return;
559 
560 	if (!norun) {
561 		if (statfs(mtpoint, &sfs) == -1) {
562 			warn("statfs: %s", mtpoint);
563 			return;
564 		}
565 		if ((sfs.f_flags & MNT_RDONLY) != 0) {
566 			if (mip->mi_forced_pw) {
567 				warnx(
568 	"Not changing mode/owner of %s since it is read-only",
569 				    mtpoint);
570 			} else {
571 				debugprintf(
572 	"Not changing mode/owner of %s since it is read-only",
573 				    mtpoint);
574 			}
575 			return;
576 		}
577 	}
578 
579 	if (mip->mi_have_mode) {
580 		debugprintf("changing mode of %s to %o.", mtpoint,
581 		    mip->mi_mode);
582 		if (!norun)
583 			if (chmod(mtpoint, mip->mi_mode) == -1)
584 				err(1, "chmod: %s", mtpoint);
585 	}
586 	/*
587 	 * We have to do these separately because the user may have
588 	 * only specified one of them.
589 	 */
590 	if (mip->mi_have_uid) {
591 		debugprintf("changing owner (user) or %s to %u.", mtpoint,
592 		    mip->mi_uid);
593 		if (!norun)
594 			if (chown(mtpoint, mip->mi_uid, -1) == -1)
595 				err(1, "chown %s to %u (user)", mtpoint,
596 				    mip->mi_uid);
597 	}
598 	if (mip->mi_have_gid) {
599 		debugprintf("changing owner (group) or %s to %u.", mtpoint,
600 		    mip->mi_gid);
601 		if (!norun)
602 			if (chown(mtpoint, -1, mip->mi_gid) == -1)
603 				err(1, "chown %s to %u (group)", mtpoint,
604 				    mip->mi_gid);
605 	}
606 }
607 
608 /*
609  * Put a file system on the memory disk.
610  */
611 static void
612 do_newfs(const char *args)
613 {
614 	int rv;
615 
616 	rv = run(NULL, "%s%s /dev/%s%d", _PATH_NEWFS, args, mdname, unit);
617 	if (rv)
618 		errx(1, "newfs exited %s %d", run_exitstr(rv),
619 		    run_exitnumber(rv));
620 }
621 
622 
623 /*
624  * Copy skel into the mountpoint.
625  */
626 static void
627 do_copy(const char *mtpoint, const char *skel)
628 {
629 	int rv;
630 
631 	rv = chdir(skel);
632 	if (rv != 0)
633 		err(1, "chdir to %s", skel);
634 	rv = run(NULL, "/bin/pax -rw -pe . %s", mtpoint);
635 	if (rv != 0)
636 		errx(1, "skel copy failed");
637 }
638 
639 /*
640  * 'str' should be a user and group name similar to the last argument
641  * to chown(1); i.e., a user, followed by a colon, followed by a
642  * group.  The user and group in 'str' may be either a [ug]id or a
643  * name.  Upon return, the uid and gid fields in 'mip' will contain
644  * the uid and gid of the user and group name in 'str', respectively.
645  *
646  * In other words, this derives a user and group id from a string
647  * formatted like the last argument to chown(1).
648  *
649  * Notice: At this point we don't support only a username or only a
650  * group name. do_mtptsetup already does, so when this feature is
651  * desired, this is the only routine that needs to be changed.
652  */
653 static void
654 extract_ugid(const char *str, struct mtpt_info *mip)
655 {
656 	char *ug;			/* Writable 'str'. */
657 	char *user, *group;		/* Result of extracton. */
658 	struct passwd *pw;
659 	struct group *gr;
660 	char *p;
661 	uid_t *uid;
662 	gid_t *gid;
663 
664 	uid = &mip->mi_uid;
665 	gid = &mip->mi_gid;
666 	mip->mi_have_uid = mip->mi_have_gid = false;
667 
668 	/* Extract the user and group from 'str'.  Format above. */
669 	ug = strdup(str);
670 	assert(ug != NULL);
671 	group = ug;
672 	user = strsep(&group, ":");
673 	if (user == NULL || group == NULL || *user == '\0' || *group == '\0')
674 		usage();
675 
676 	/* Derive uid. */
677 	*uid = strtoul(user, &p, 10);
678 	if (*uid == (uid_t)ULONG_MAX)
679 		usage();
680 	if (*p != '\0') {
681 		pw = getpwnam(user);
682 		if (pw == NULL)
683 			errx(1, "invalid user: %s", user);
684 		*uid = pw->pw_uid;
685 	}
686 	mip->mi_have_uid = true;
687 
688 	/* Derive gid. */
689 	*gid = strtoul(group, &p, 10);
690 	if (*gid == (gid_t)ULONG_MAX)
691 		usage();
692 	if (*p != '\0') {
693 		gr = getgrnam(group);
694 		if (gr == NULL)
695 			errx(1, "invalid group: %s", group);
696 		*gid = gr->gr_gid;
697 	}
698 	mip->mi_have_gid = true;
699 
700 	free(ug);
701 }
702 
703 /*
704  * Run a process with command name and arguments pointed to by the
705  * formatted string 'cmdline'.  Since system(3) is not used, the first
706  * space-delimited token of 'cmdline' must be the full pathname of the
707  * program to run.
708  *
709  * The return value is the return code of the process spawned, or a negative
710  * signal number if the process exited due to an uncaught signal.
711  *
712  * If 'ofd' is non-NULL, it is set to the standard output of
713  * the program spawned (i.e., you can read from ofd and get the output
714  * of the program).
715  */
716 static int
717 run(int *ofd, const char *cmdline, ...)
718 {
719 	char **argv, **argvp;		/* Result of splitting 'cmd'. */
720 	int argc;
721 	char *cmd;			/* Expansion of 'cmdline'. */
722 	int pid, status;		/* Child info. */
723 	int pfd[2];			/* Pipe to the child. */
724 	int nfd;			/* Null (/dev/null) file descriptor. */
725 	bool dup2dn;			/* Dup /dev/null to stdout? */
726 	va_list ap;
727 	char *p;
728 	int rv, i;
729 
730 	dup2dn = true;
731 	va_start(ap, cmdline);
732 	rv = vasprintf(&cmd, cmdline, ap);
733 	if (rv == -1)
734 		err(1, "vasprintf");
735 	va_end(ap);
736 
737 	/* Split up 'cmd' into 'argv' for use with execve. */
738 	for (argc = 1, p = cmd; (p = strchr(p, ' ')) != NULL; p++)
739 		argc++;		/* 'argc' generation loop. */
740 	argv = (char **)malloc(sizeof(*argv) * (argc + 1));
741 	assert(argv != NULL);
742 	for (p = cmd, argvp = argv; (*argvp = strsep(&p, " ")) != NULL;)
743 		if (**argvp != '\0')
744 			if (++argvp >= &argv[argc]) {
745 				*argvp = NULL;
746 				break;
747 			}
748 	assert(*argv);
749 	/* The argv array ends up NULL-terminated here. */
750 
751 	/* Make sure the above loop works as expected. */
752 	if (debug) {
753 		/*
754 		 * We can't, but should, use debugprintf here.  First,
755 		 * it appends a trailing newline to the output, and
756 		 * second it prepends "DEBUG: " to the output.  The
757 		 * former is a problem for this would-be first call,
758 		 * and the latter for the would-be call inside the
759 		 * loop.
760 		 */
761 		(void)fprintf(stderr, "DEBUG: running:");
762 		/* Should be equivalent to 'cmd' (before strsep, of course). */
763 		for (i = 0; argv[i] != NULL; i++)
764 			(void)fprintf(stderr, " %s", argv[i]);
765 		(void)fprintf(stderr, "\n");
766 	}
767 
768 	/* Create a pipe if necessary and fork the helper program. */
769 	if (ofd != NULL) {
770 		if (pipe(&pfd[0]) == -1)
771 			err(1, "pipe");
772 		*ofd = pfd[0];
773 		dup2dn = false;
774 	}
775 	pid = fork();
776 	switch (pid) {
777 	case 0:
778 		/* XXX can we call err() in here? */
779 		if (norun)
780 			_exit(0);
781 		if (ofd != NULL)
782 			if (dup2(pfd[1], STDOUT_FILENO) < 0)
783 				err(1, "dup2");
784 		if (!loudsubs) {
785 			nfd = open(_PATH_DEVNULL, O_RDWR);
786 			if (nfd == -1)
787 				err(1, "open: %s", _PATH_DEVNULL);
788 			if (dup2(nfd, STDIN_FILENO) < 0)
789 				err(1, "dup2");
790 			if (dup2dn)
791 				if (dup2(nfd, STDOUT_FILENO) < 0)
792 				   err(1, "dup2");
793 			if (dup2(nfd, STDERR_FILENO) < 0)
794 				err(1, "dup2");
795 		}
796 
797 		(void)execv(argv[0], argv);
798 		warn("exec: %s", argv[0]);
799 		_exit(-1);
800 	case -1:
801 		err(1, "fork");
802 	}
803 
804 	free(cmd);
805 	free(argv);
806 	while (waitpid(pid, &status, 0) != pid)
807 		;
808 	if (WIFEXITED(status))
809 		return (WEXITSTATUS(status));
810 	if (WIFSIGNALED(status))
811 		return (-WTERMSIG(status));
812 	err(1, "unexpected waitpid status: 0x%x", status);
813 }
814 
815 /*
816  * If run() returns non-zero, provide a string explaining why.
817  */
818 static const char *
819 run_exitstr(int rv)
820 {
821 	if (rv > 0)
822 		return ("with error code");
823 	if (rv < 0)
824 		return ("with signal");
825 	return (NULL);
826 }
827 
828 /*
829  * If run returns non-zero, provide a relevant number.
830  */
831 static int
832 run_exitnumber(int rv)
833 {
834 	if (rv < 0)
835 		return (-rv);
836 	return (rv);
837 }
838 
839 static void
840 usage(void)
841 {
842 
843 	fprintf(stderr,
844 "usage: %s [-DLlMNnPStUX] [-a maxcontig] [-b block-size]\n"
845 "\t[-c blocks-per-cylinder-group][-d max-extent-size] [-E path-mdconfig]\n"
846 "\t[-e maxbpg] [-F file] [-f frag-size] [-i bytes] [-k skel]\n"
847 "\t[-m percent-free] [-O optimization] [-o mount-options]\n"
848 "\t[-p permissions] [-s size] [-v version] [-w user:group]\n"
849 "\tmd-device mount-point\n", getprogname());
850 	exit(1);
851 }
852