xref: /freebsd-12.1/sbin/mdmfs/mdmfs.c (revision 7dd277a9)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include <sys/param.h>
39 #include <sys/linker.h>
40 #include <sys/mdioctl.h>
41 #include <sys/module.h>
42 #include <sys/mount.h>
43 #include <sys/stat.h>
44 #include <sys/wait.h>
45 
46 #include <assert.h>
47 #include <err.h>
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <grp.h>
51 #include <inttypes.h>
52 #include <paths.h>
53 #include <pwd.h>
54 #include <stdarg.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <ctype.h>
59 #include <unistd.h>
60 
61 typedef enum { false, true } bool;
62 
63 struct mtpt_info {
64 	uid_t		 mi_uid;
65 	bool		 mi_have_uid;
66 	gid_t		 mi_gid;
67 	bool		 mi_have_gid;
68 	mode_t		 mi_mode;
69 	bool		 mi_have_mode;
70 	bool		 mi_forced_pw;
71 };
72 
73 static	bool debug;		/* Emit debugging information? */
74 static	bool loudsubs;		/* Suppress output from helper programs? */
75 static	bool norun;		/* Actually run the helper programs? */
76 static	int unit;      		/* The unit we're working with. */
77 static	const char *mdname;	/* Name of memory disk device (e.g., "md"). */
78 static	const char *mdsuffix;	/* Suffix of memory disk device (e.g., ".uzip"). */
79 static	size_t mdnamelen;	/* Length of mdname. */
80 static	const char *path_mdconfig =_PATH_MDCONFIG;
81 
82 static void	 argappend(char **, const char *, ...) __printflike(2, 3);
83 static void	 debugprintf(const char *, ...) __printflike(1, 2);
84 static void	 do_mdconfig_attach(const char *, const enum md_types);
85 static void	 do_mdconfig_attach_au(const char *, const enum md_types);
86 static void	 do_mdconfig_detach(void);
87 static void	 do_mount_md(const char *, const char *);
88 static void	 do_mount_tmpfs(const char *, const char *);
89 static void	 do_mtptsetup(const char *, struct mtpt_info *);
90 static void	 do_newfs(const char *);
91 static void	 extract_ugid(const char *, struct mtpt_info *);
92 static int	 run(int *, const char *, ...) __printflike(2, 3);
93 static void	 usage(void);
94 
95 int
main(int argc,char ** argv)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, *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 	mdtype = MD_SWAP;
120 	mdname = MD_NAME;
121 	mdnamelen = strlen(mdname);
122 	mdsize = 0;
123 	/*
124 	 * Can't set these to NULL.  They may be passed to the
125 	 * respective programs without modification.  I.e., we may not
126 	 * receive any command-line options which will caused them to
127 	 * be modified.
128 	 */
129 	mdconfig_arg = strdup("");
130 	newfs_arg = strdup("");
131 	mount_arg = strdup("");
132 	size_arg = NULL;
133 
134 	/* If we were started as mount_mfs or mfs, imply -C. */
135 	if (strcmp(getprogname(), "mount_mfs") == 0 ||
136 	    strcmp(getprogname(), "mfs") == 0) {
137 		/* Make compatibility assumptions. */
138 		mi.mi_mode = 01777;
139 		mi.mi_have_mode = true;
140 	}
141 
142 	while ((ch = getopt(argc, argv,
143 	    "a:b:Cc:Dd:E:e:F:f:hi:LlMm:NnO:o:Pp:Ss:tT:Uv:w:X")) != -1)
144 		switch (ch) {
145 		case 'a':
146 			argappend(&newfs_arg, "-a %s", optarg);
147 			break;
148 		case 'b':
149 			argappend(&newfs_arg, "-b %s", optarg);
150 			break;
151 		case 'C':
152 			/* Ignored for compatibility. */
153 			break;
154 		case 'c':
155 			argappend(&newfs_arg, "-c %s", optarg);
156 			break;
157 		case 'D':
158 			detach = false;
159 			break;
160 		case 'd':
161 			argappend(&newfs_arg, "-d %s", optarg);
162 			break;
163 		case 'E':
164 			path_mdconfig = optarg;
165 			break;
166 		case 'e':
167 			argappend(&newfs_arg, "-e %s", optarg);
168 			break;
169 		case 'F':
170 			if (have_mdtype)
171 				usage();
172 			mdtype = MD_VNODE;
173 			have_mdtype = true;
174 			argappend(&mdconfig_arg, "-f %s", optarg);
175 			break;
176 		case 'f':
177 			argappend(&newfs_arg, "-f %s", optarg);
178 			break;
179 		case 'h':
180 			usage();
181 			break;
182 		case 'i':
183 			argappend(&newfs_arg, "-i %s", optarg);
184 			break;
185 		case 'L':
186 			loudsubs = true;
187 			break;
188 		case 'l':
189 			mlmac = true;
190 			argappend(&newfs_arg, "-l");
191 			break;
192 		case 'M':
193 			if (have_mdtype)
194 				usage();
195 			mdtype = MD_MALLOC;
196 			have_mdtype = true;
197 			argappend(&mdconfig_arg, "-o reserve");
198 			break;
199 		case 'm':
200 			argappend(&newfs_arg, "-m %s", optarg);
201 			break;
202 		case 'N':
203 			norun = true;
204 			break;
205 		case 'n':
206 			argappend(&newfs_arg, "-n");
207 			break;
208 		case 'O':
209 			argappend(&newfs_arg, "-o %s", optarg);
210 			break;
211 		case 'o':
212 			argappend(&mount_arg, "-o %s", optarg);
213 			break;
214 		case 'P':
215 			newfs = false;
216 			break;
217 		case 'p':
218 			if ((set = setmode(optarg)) == NULL)
219 				usage();
220 			mi.mi_mode = getmode(set, S_IRWXU | S_IRWXG | S_IRWXO);
221 			mi.mi_have_mode = true;
222 			mi.mi_forced_pw = true;
223 			free(set);
224 			break;
225 		case 'S':
226 			softdep = false;
227 			break;
228 		case 's':
229 			size_arg = optarg;
230 			break;
231 		case 't':
232 			argappend(&newfs_arg, "-t");
233 			break;
234 		case 'T':
235 			argappend(&mount_arg, "-t %s", optarg);
236 			break;
237 		case 'U':
238 			softdep = true;
239 			break;
240 		case 'v':
241 			argappend(&newfs_arg, "-O %s", optarg);
242 			break;
243 		case 'w':
244 			extract_ugid(optarg, &mi);
245 			mi.mi_forced_pw = true;
246 			break;
247 		case 'X':
248 			debug = true;
249 			break;
250 		default:
251 			usage();
252 		}
253 	argc -= optind;
254 	argv += optind;
255 	if (argc < 2)
256 		usage();
257 
258 	/*
259 	 * Historically our size arg was passed directly to mdconfig, which
260 	 * treats a number without a suffix as a count of 512-byte sectors;
261 	 * tmpfs would treat it as a count of bytes.  To get predictable
262 	 * behavior for 'auto' we document that the size always uses mdconfig
263 	 * rules.  To make that work, decode the size here so it can be passed
264 	 * to either tmpfs or mdconfig as a count of bytes.
265 	 */
266 	if (size_arg != NULL) {
267 		mdsize = (intmax_t)strtoumax(size_arg, &p, 0);
268 		if (p == size_arg || (p[0] != 0 && p[1] != 0) || mdsize < 0)
269 			errx(1, "invalid size '%s'", size_arg);
270 		switch (*p) {
271 		case 'p':
272 		case 'P':
273 			mdsize *= 1024;
274 		case 't':
275 		case 'T':
276 			mdsize *= 1024;
277 		case 'g':
278 		case 'G':
279 			mdsize *= 1024;
280 		case 'm':
281 		case 'M':
282 			mdsize *= 1024;
283 		case 'k':
284 		case 'K':
285 			mdsize *= 1024;
286 		case 'b':
287 		case 'B':
288 			break;
289 		case '\0':
290 			mdsize *= 512;
291 			break;
292 		default:
293 			errx(1, "invalid size suffix on '%s'", size_arg);
294 		}
295 	}
296 
297 	/*
298 	 * Based on the command line 'md-device' either mount a tmpfs filesystem
299 	 * or configure the md device then format and mount a filesystem on it.
300 	 * If the device is 'auto' use tmpfs if it is available and there is no
301 	 * request for multilabel MAC (which tmpfs does not support).
302 	 */
303 	unitstr = argv[0];
304 	mtpoint = argv[1];
305 
306 	if (strcmp(unitstr, "auto") == 0) {
307 		if (mlmac)
308 			idx = -1; /* Must use md for mlmac. */
309 		else if ((idx = modfind("tmpfs")) == -1)
310 			idx = kldload("tmpfs");
311 		if (idx == -1)
312 			unitstr = "md";
313 		else
314 			unitstr = "tmpfs";
315 	}
316 
317 	if (strcmp(unitstr, "tmpfs") == 0) {
318 		if (size_arg != NULL && mdsize != 0)
319 			argappend(&mount_arg, "-o size=%jd", mdsize);
320 		do_mount_tmpfs(mount_arg, mtpoint);
321 	} else {
322 		if (size_arg != NULL)
323 			argappend(&mdconfig_arg, "-s %jdB", mdsize);
324 		if (strncmp(unitstr, "/dev/", 5) == 0)
325 			unitstr += 5;
326 		if (strncmp(unitstr, mdname, mdnamelen) == 0)
327 			unitstr += mdnamelen;
328 		if (!isdigit(*unitstr)) {
329 			autounit = true;
330 			unit = -1;
331 			mdsuffix = unitstr;
332 		} else {
333 			ul = strtoul(unitstr, &p, 10);
334 			if (ul == ULONG_MAX)
335 				errx(1, "bad device unit: %s", unitstr);
336 			unit = ul;
337 			mdsuffix = p;	/* can be empty */
338 		}
339 
340 		if (!have_mdtype)
341 			mdtype = MD_SWAP;
342 		if (softdep)
343 			argappend(&newfs_arg, "-U");
344 		if (mdtype != MD_VNODE && !newfs)
345 			errx(1, "-P requires a vnode-backed disk");
346 
347 		/* Do the work. */
348 		if (detach && !autounit)
349 			do_mdconfig_detach();
350 		if (autounit)
351 			do_mdconfig_attach_au(mdconfig_arg, mdtype);
352 		else
353 			do_mdconfig_attach(mdconfig_arg, mdtype);
354 		if (newfs)
355 			do_newfs(newfs_arg);
356 		do_mount_md(mount_arg, mtpoint);
357 	}
358 
359 	do_mtptsetup(mtpoint, &mi);
360 
361 	return (0);
362 }
363 
364 /*
365  * Append the expansion of 'fmt' to the buffer pointed to by '*dstp';
366  * reallocate as required.
367  */
368 static void
argappend(char ** dstp,const char * fmt,...)369 argappend(char **dstp, const char *fmt, ...)
370 {
371 	char *old, *new;
372 	va_list ap;
373 
374 	old = *dstp;
375 	assert(old != NULL);
376 
377 	va_start(ap, fmt);
378 	if (vasprintf(&new, fmt,ap) == -1)
379 		errx(1, "vasprintf");
380 	va_end(ap);
381 
382 	*dstp = new;
383 	if (asprintf(&new, "%s %s", old, new) == -1)
384 		errx(1, "asprintf");
385 	free(*dstp);
386 	free(old);
387 
388 	*dstp = new;
389 }
390 
391 /*
392  * If run-time debugging is enabled, print the expansion of 'fmt'.
393  * Otherwise, do nothing.
394  */
395 static void
debugprintf(const char * fmt,...)396 debugprintf(const char *fmt, ...)
397 {
398 	va_list ap;
399 
400 	if (!debug)
401 		return;
402 	fprintf(stderr, "DEBUG: ");
403 	va_start(ap, fmt);
404 	vfprintf(stderr, fmt, ap);
405 	va_end(ap);
406 	fprintf(stderr, "\n");
407 	fflush(stderr);
408 }
409 
410 /*
411  * Attach a memory disk with a known unit.
412  */
413 static void
do_mdconfig_attach(const char * args,const enum md_types mdtype)414 do_mdconfig_attach(const char *args, const enum md_types mdtype)
415 {
416 	int rv;
417 	const char *ta;		/* Type arg. */
418 
419 	switch (mdtype) {
420 	case MD_SWAP:
421 		ta = "-t swap";
422 		break;
423 	case MD_VNODE:
424 		ta = "-t vnode";
425 		break;
426 	case MD_MALLOC:
427 		ta = "-t malloc";
428 		break;
429 	default:
430 		abort();
431 	}
432 	rv = run(NULL, "%s -a %s%s -u %s%d", path_mdconfig, ta, args,
433 	    mdname, unit);
434 	if (rv)
435 		errx(1, "mdconfig (attach) exited with error code %d", rv);
436 }
437 
438 /*
439  * Attach a memory disk with an unknown unit; use autounit.
440  */
441 static void
do_mdconfig_attach_au(const char * args,const enum md_types mdtype)442 do_mdconfig_attach_au(const char *args, const enum md_types mdtype)
443 {
444 	const char *ta;		/* Type arg. */
445 	char *linep;
446 	char linebuf[12];	/* 32-bit unit (10) + '\n' (1) + '\0' (1) */
447 	int fd;			/* Standard output of mdconfig invocation. */
448 	FILE *sfd;
449 	int rv;
450 	char *p;
451 	size_t linelen;
452 	unsigned long ul;
453 
454 	switch (mdtype) {
455 	case MD_SWAP:
456 		ta = "-t swap";
457 		break;
458 	case MD_VNODE:
459 		ta = "-t vnode";
460 		break;
461 	case MD_MALLOC:
462 		ta = "-t malloc";
463 		break;
464 	default:
465 		abort();
466 	}
467 	rv = run(&fd, "%s -a %s%s", path_mdconfig, ta, args);
468 	if (rv)
469 		errx(1, "mdconfig (attach) exited with error code %d", rv);
470 
471 	/* Receive the unit number. */
472 	if (norun) {	/* Since we didn't run, we can't read.  Fake it. */
473 		unit = 0;
474 		return;
475 	}
476 	sfd = fdopen(fd, "r");
477 	if (sfd == NULL)
478 		err(1, "fdopen");
479 	linep = fgetln(sfd, &linelen);
480 	/* If the output format changes, we want to know about it. */
481 	if (linep == NULL || linelen <= mdnamelen + 1 ||
482 	    linelen - mdnamelen >= sizeof(linebuf) ||
483 	    strncmp(linep, mdname, mdnamelen) != 0)
484 		errx(1, "unexpected output from mdconfig (attach)");
485 	linep += mdnamelen;
486 	linelen -= mdnamelen;
487 	/* Can't use strlcpy because linep is not NULL-terminated. */
488 	strncpy(linebuf, linep, linelen);
489 	linebuf[linelen] = '\0';
490 	ul = strtoul(linebuf, &p, 10);
491 	if (ul == ULONG_MAX || *p != '\n')
492 		errx(1, "unexpected output from mdconfig (attach)");
493 	unit = ul;
494 
495 	fclose(sfd);
496 }
497 
498 /*
499  * Detach a memory disk.
500  */
501 static void
do_mdconfig_detach(void)502 do_mdconfig_detach(void)
503 {
504 	int rv;
505 
506 	rv = run(NULL, "%s -d -u %s%d", path_mdconfig, mdname, unit);
507 	if (rv && debug)	/* This is allowed to fail. */
508 		warnx("mdconfig (detach) exited with error code %d (ignored)",
509 		    rv);
510 }
511 
512 /*
513  * Mount the configured memory disk.
514  */
515 static void
do_mount_md(const char * args,const char * mtpoint)516 do_mount_md(const char *args, const char *mtpoint)
517 {
518 	int rv;
519 
520 	rv = run(NULL, "%s%s /dev/%s%d%s %s", _PATH_MOUNT, args,
521 	    mdname, unit, mdsuffix, mtpoint);
522 	if (rv)
523 		errx(1, "mount exited with error code %d", rv);
524 }
525 
526 /*
527  * Mount the configured tmpfs.
528  */
529 static void
do_mount_tmpfs(const char * args,const char * mtpoint)530 do_mount_tmpfs(const char *args, const char *mtpoint)
531 {
532 	int rv;
533 
534 	rv = run(NULL, "%s -t tmpfs %s tmp %s", _PATH_MOUNT, args, mtpoint);
535 	if (rv)
536 		errx(1, "tmpfs mount exited with error code %d", rv);
537 }
538 
539 /*
540  * Various configuration of the mountpoint.  Mostly, enact 'mip'.
541  */
542 static void
do_mtptsetup(const char * mtpoint,struct mtpt_info * mip)543 do_mtptsetup(const char *mtpoint, struct mtpt_info *mip)
544 {
545 	struct statfs sfs;
546 
547 	if (!mip->mi_have_mode && !mip->mi_have_uid && !mip->mi_have_gid)
548 		return;
549 
550 	if (!norun) {
551 		if (statfs(mtpoint, &sfs) == -1) {
552 			warn("statfs: %s", mtpoint);
553 			return;
554 		}
555 		if ((sfs.f_flags & MNT_RDONLY) != 0) {
556 			if (mip->mi_forced_pw) {
557 				warnx(
558 	"Not changing mode/owner of %s since it is read-only",
559 				    mtpoint);
560 			} else {
561 				debugprintf(
562 	"Not changing mode/owner of %s since it is read-only",
563 				    mtpoint);
564 			}
565 			return;
566 		}
567 	}
568 
569 	if (mip->mi_have_mode) {
570 		debugprintf("changing mode of %s to %o.", mtpoint,
571 		    mip->mi_mode);
572 		if (!norun)
573 			if (chmod(mtpoint, mip->mi_mode) == -1)
574 				err(1, "chmod: %s", mtpoint);
575 	}
576 	/*
577 	 * We have to do these separately because the user may have
578 	 * only specified one of them.
579 	 */
580 	if (mip->mi_have_uid) {
581 		debugprintf("changing owner (user) or %s to %u.", mtpoint,
582 		    mip->mi_uid);
583 		if (!norun)
584 			if (chown(mtpoint, mip->mi_uid, -1) == -1)
585 				err(1, "chown %s to %u (user)", mtpoint,
586 				    mip->mi_uid);
587 	}
588 	if (mip->mi_have_gid) {
589 		debugprintf("changing owner (group) or %s to %u.", mtpoint,
590 		    mip->mi_gid);
591 		if (!norun)
592 			if (chown(mtpoint, -1, mip->mi_gid) == -1)
593 				err(1, "chown %s to %u (group)", mtpoint,
594 				    mip->mi_gid);
595 	}
596 }
597 
598 /*
599  * Put a file system on the memory disk.
600  */
601 static void
do_newfs(const char * args)602 do_newfs(const char *args)
603 {
604 	int rv;
605 
606 	rv = run(NULL, "%s%s /dev/%s%d", _PATH_NEWFS, args, mdname, unit);
607 	if (rv)
608 		errx(1, "newfs exited with error code %d", rv);
609 }
610 
611 /*
612  * 'str' should be a user and group name similar to the last argument
613  * to chown(1); i.e., a user, followed by a colon, followed by a
614  * group.  The user and group in 'str' may be either a [ug]id or a
615  * name.  Upon return, the uid and gid fields in 'mip' will contain
616  * the uid and gid of the user and group name in 'str', respectively.
617  *
618  * In other words, this derives a user and group id from a string
619  * formatted like the last argument to chown(1).
620  *
621  * Notice: At this point we don't support only a username or only a
622  * group name. do_mtptsetup already does, so when this feature is
623  * desired, this is the only routine that needs to be changed.
624  */
625 static void
extract_ugid(const char * str,struct mtpt_info * mip)626 extract_ugid(const char *str, struct mtpt_info *mip)
627 {
628 	char *ug;			/* Writable 'str'. */
629 	char *user, *group;		/* Result of extracton. */
630 	struct passwd *pw;
631 	struct group *gr;
632 	char *p;
633 	uid_t *uid;
634 	gid_t *gid;
635 
636 	uid = &mip->mi_uid;
637 	gid = &mip->mi_gid;
638 	mip->mi_have_uid = mip->mi_have_gid = false;
639 
640 	/* Extract the user and group from 'str'.  Format above. */
641 	ug = strdup(str);
642 	assert(ug != NULL);
643 	group = ug;
644 	user = strsep(&group, ":");
645 	if (user == NULL || group == NULL || *user == '\0' || *group == '\0')
646 		usage();
647 
648 	/* Derive uid. */
649 	*uid = strtoul(user, &p, 10);
650 	if (*uid == (uid_t)ULONG_MAX)
651 		usage();
652 	if (*p != '\0') {
653 		pw = getpwnam(user);
654 		if (pw == NULL)
655 			errx(1, "invalid user: %s", user);
656 		*uid = pw->pw_uid;
657 	}
658 	mip->mi_have_uid = true;
659 
660 	/* Derive gid. */
661 	*gid = strtoul(group, &p, 10);
662 	if (*gid == (gid_t)ULONG_MAX)
663 		usage();
664 	if (*p != '\0') {
665 		gr = getgrnam(group);
666 		if (gr == NULL)
667 			errx(1, "invalid group: %s", group);
668 		*gid = gr->gr_gid;
669 	}
670 	mip->mi_have_gid = true;
671 
672 	free(ug);
673 }
674 
675 /*
676  * Run a process with command name and arguments pointed to by the
677  * formatted string 'cmdline'.  Since system(3) is not used, the first
678  * space-delimited token of 'cmdline' must be the full pathname of the
679  * program to run.  The return value is the return code of the process
680  * spawned.  If 'ofd' is non-NULL, it is set to the standard output of
681  * the program spawned (i.e., you can read from ofd and get the output
682  * of the program).
683  */
684 static int
run(int * ofd,const char * cmdline,...)685 run(int *ofd, const char *cmdline, ...)
686 {
687 	char **argv, **argvp;		/* Result of splitting 'cmd'. */
688 	int argc;
689 	char *cmd;			/* Expansion of 'cmdline'. */
690 	int pid, status;		/* Child info. */
691 	int pfd[2];			/* Pipe to the child. */
692 	int nfd;			/* Null (/dev/null) file descriptor. */
693 	bool dup2dn;			/* Dup /dev/null to stdout? */
694 	va_list ap;
695 	char *p;
696 	int rv, i;
697 
698 	dup2dn = true;
699 	va_start(ap, cmdline);
700 	rv = vasprintf(&cmd, cmdline, ap);
701 	if (rv == -1)
702 		err(1, "vasprintf");
703 	va_end(ap);
704 
705 	/* Split up 'cmd' into 'argv' for use with execve. */
706 	for (argc = 1, p = cmd; (p = strchr(p, ' ')) != NULL; p++)
707 		argc++;		/* 'argc' generation loop. */
708 	argv = (char **)malloc(sizeof(*argv) * (argc + 1));
709 	assert(argv != NULL);
710 	for (p = cmd, argvp = argv; (*argvp = strsep(&p, " ")) != NULL;)
711 		if (**argvp != '\0')
712 			if (++argvp >= &argv[argc]) {
713 				*argvp = NULL;
714 				break;
715 			}
716 	assert(*argv);
717 	/* The argv array ends up NULL-terminated here. */
718 
719 	/* Make sure the above loop works as expected. */
720 	if (debug) {
721 		/*
722 		 * We can't, but should, use debugprintf here.  First,
723 		 * it appends a trailing newline to the output, and
724 		 * second it prepends "DEBUG: " to the output.  The
725 		 * former is a problem for this would-be first call,
726 		 * and the latter for the would-be call inside the
727 		 * loop.
728 		 */
729 		(void)fprintf(stderr, "DEBUG: running:");
730 		/* Should be equivalent to 'cmd' (before strsep, of course). */
731 		for (i = 0; argv[i] != NULL; i++)
732 			(void)fprintf(stderr, " %s", argv[i]);
733 		(void)fprintf(stderr, "\n");
734 	}
735 
736 	/* Create a pipe if necessary and fork the helper program. */
737 	if (ofd != NULL) {
738 		if (pipe(&pfd[0]) == -1)
739 			err(1, "pipe");
740 		*ofd = pfd[0];
741 		dup2dn = false;
742 	}
743 	pid = fork();
744 	switch (pid) {
745 	case 0:
746 		/* XXX can we call err() in here? */
747 		if (norun)
748 			_exit(0);
749 		if (ofd != NULL)
750 			if (dup2(pfd[1], STDOUT_FILENO) < 0)
751 				err(1, "dup2");
752 		if (!loudsubs) {
753 			nfd = open(_PATH_DEVNULL, O_RDWR);
754 			if (nfd == -1)
755 				err(1, "open: %s", _PATH_DEVNULL);
756 			if (dup2(nfd, STDIN_FILENO) < 0)
757 				err(1, "dup2");
758 			if (dup2dn)
759 				if (dup2(nfd, STDOUT_FILENO) < 0)
760 				   err(1, "dup2");
761 			if (dup2(nfd, STDERR_FILENO) < 0)
762 				err(1, "dup2");
763 		}
764 
765 		(void)execv(argv[0], argv);
766 		warn("exec: %s", argv[0]);
767 		_exit(-1);
768 	case -1:
769 		err(1, "fork");
770 	}
771 
772 	free(cmd);
773 	free(argv);
774 	while (waitpid(pid, &status, 0) != pid)
775 		;
776 	return (WEXITSTATUS(status));
777 }
778 
779 static void
usage(void)780 usage(void)
781 {
782 
783 	fprintf(stderr,
784 "usage: %s [-DLlMNnPStUX] [-a maxcontig] [-b block-size]\n"
785 "\t[-c blocks-per-cylinder-group][-d max-extent-size] [-E path-mdconfig]\n"
786 "\t[-e maxbpg] [-F file] [-f frag-size] [-i bytes] [-m percent-free]\n"
787 "\t[-O optimization] [-o mount-options]\n"
788 "\t[-p permissions] [-s size] [-v version] [-w user:group]\n"
789 "\tmd-device mount-point\n", getprogname());
790 	exit(1);
791 }
792