swapctl.c revision 1.24 
1/*	$OpenBSD: swapctl.c,v 1.24 2019/06/28 13:32:46 deraadt Exp $	*/
2/*	$NetBSD: swapctl.c,v 1.9 1998/07/26 20:23:15 mycroft Exp $	*/
3
4/*
5 * Copyright (c) 1996, 1997 Matthew R. Green
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
24 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27 * 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 * swapctl command:
34 *	-A		add all devices listed as `sw' in /etc/fstab
35 *	-t [blk|noblk]	if -A, add either all block device or all non-block
36 *			devices
37 *	-a <path>	add this device
38 *	-d <path>	remove this swap device
39 *	-l		list swap devices
40 *	-s		short listing of swap devices
41 *	-k		use kilobytes
42 *	-p <pri>	use this priority
43 *	-c <path>	change priority
44 *
45 * or, if invoked as "swapon" (compatibility mode):
46 *
47 *	-a		all devices listed as `sw' in /etc/fstab
48 *	-t		same as -t above (feature not present in old
49 *			swapon(8) command)
50 *	<dev>		add this device
51 */
52
53#include <sys/stat.h>
54#include <sys/swap.h>
55#include <sys/wait.h>
56
57#include <unistd.h>
58#include <err.h>
59#include <errno.h>
60#include <stdio.h>
61#include <stdlib.h>
62#include <limits.h>
63#include <string.h>
64#include <fstab.h>
65#include <util.h>
66
67#include "swapctl.h"
68
69int	command;
70
71/*
72 * Commands for swapctl(8).  These are mutually exclusive.
73 */
74#define	CMD_A		0x01	/* process /etc/fstab */
75#define	CMD_a		0x02	/* add a swap file/device */
76#define	CMD_c		0x04	/* change priority of a swap file/device */
77#define	CMD_d		0x08	/* delete a swap file/device */
78#define	CMD_l		0x10	/* list swap files/devices */
79#define	CMD_s		0x20	/* summary of swap files/devices */
80
81#define	SET_COMMAND(cmd) \
82do { \
83	if (command) \
84		usage(); \
85	command = (cmd); \
86} while (0)
87
88/*
89 * Commands that require a "path" argument at the end of the command
90 * line, and the ones which require that none exist.
91 */
92#define	REQUIRE_PATH	(CMD_a | CMD_c | CMD_d)
93#define	REQUIRE_NOPATH	(CMD_A | CMD_l | CMD_s)
94
95/*
96 * Option flags, and the commands with which they are valid.
97 */
98int	kflag;		/* display in 1K blocks */
99#define	KFLAG_CMDS	(CMD_l | CMD_s)
100
101int	pflag;		/* priority was specified */
102#define	PFLAG_CMDS	(CMD_A | CMD_a | CMD_c)
103
104char	*tflag;		/* swap device type (blk or noblk) */
105#define	TFLAG_CMDS	(CMD_A)
106
107int	pri;		/* uses 0 as default pri */
108
109static	void change_priority(char *);
110static	void add_swap(char *);
111static	void del_swap(char *);
112static	void do_fstab(void);
113static	void usage(void);
114static	int  swapon_command(int, char **);
115
116extern	char *__progname;	/* from crt0.o */
117
118int
119main(int argc, char *argv[])
120{
121	const char *errstr;
122	int	c;
123
124	if (strcmp(__progname, "swapon") == 0)
125		return swapon_command(argc, argv);
126
127	while ((c = getopt(argc, argv, "Aacdlkp:st:")) != -1) {
128		switch (c) {
129		case 'A':
130			SET_COMMAND(CMD_A);
131			break;
132
133		case 'a':
134			SET_COMMAND(CMD_a);
135			break;
136
137		case 'c':
138			SET_COMMAND(CMD_c);
139			break;
140
141		case 'd':
142			SET_COMMAND(CMD_d);
143			break;
144
145		case 'l':
146			SET_COMMAND(CMD_l);
147			break;
148
149		case 'k':
150			kflag = 1;
151			break;
152
153		case 'p':
154			pflag = 1;
155			pri = strtonum(optarg, 0, INT_MAX, &errstr);
156			if (errstr)
157				errx(1, "-p %s: %s", errstr, optarg);
158			break;
159
160		case 's':
161			SET_COMMAND(CMD_s);
162			break;
163
164		case 't':
165			if (tflag != NULL)
166				usage();
167			tflag = optarg;
168			break;
169
170		default:
171			usage();
172			/* NOTREACHED */
173		}
174	}
175
176	argv += optind;
177	argc -= optind;
178
179	/* Did the user specify a command? */
180	if (command == 0) {
181		if (argc == 0)
182			SET_COMMAND(CMD_l);
183		else
184			usage();
185	}
186
187	switch (argc) {
188	case 0:
189		if (command & REQUIRE_PATH)
190			usage();
191		break;
192
193	case 1:
194		if (command & REQUIRE_NOPATH)
195			usage();
196		break;
197
198	default:
199		usage();
200	}
201
202	/* To change priority, you have to specify one. */
203	if ((command == CMD_c) && pflag == 0)
204		usage();
205
206	/* Sanity-check -t */
207	if (tflag != NULL) {
208		if (command != CMD_A)
209			usage();
210		if (strcmp(tflag, "blk") != 0 &&
211		    strcmp(tflag, "noblk") != 0)
212			usage();
213	}
214
215	/* Dispatch the command. */
216	switch (command) {
217	case CMD_l:
218		list_swap(pri, kflag, pflag, 1);
219		break;
220
221	case CMD_s:
222		list_swap(pri, kflag, pflag, 0);
223		break;
224
225	case CMD_c:
226		change_priority(argv[0]);
227		break;
228
229	case CMD_a:
230		add_swap(argv[0]);
231		break;
232
233	case CMD_d:
234		del_swap(argv[0]);
235		break;
236
237	case CMD_A:
238		do_fstab();
239		break;
240	}
241
242	return (0);
243}
244
245/*
246 * swapon_command: emulate the old swapon(8) program.
247 */
248int
249swapon_command(int argc, char **argv)
250{
251	int ch, fiztab = 0;
252
253	while ((ch = getopt(argc, argv, "at:")) != -1) {
254		switch (ch) {
255		case 'a':
256			fiztab = 1;
257			break;
258		case 't':
259			if (tflag != NULL)
260				usage();
261			tflag = optarg;
262			break;
263		default:
264			goto swapon_usage;
265		}
266	}
267	argc -= optind;
268	argv += optind;
269
270	if (fiztab) {
271		if (argc)
272			goto swapon_usage;
273		/* Sanity-check -t */
274		if (tflag != NULL) {
275			if (strcmp(tflag, "blk") != 0 &&
276			    strcmp(tflag, "noblk") != 0)
277				usage();
278		}
279		do_fstab();
280		return (0);
281	} else if (argc == 0 || tflag != NULL)
282		goto swapon_usage;
283
284	while (argc) {
285		add_swap(argv[0]);
286		argc--;
287		argv++;
288	}
289	return (0);
290
291 swapon_usage:
292	fprintf(stderr, "usage: %s -a | path\n", __progname);
293	return (1);
294}
295
296/*
297 * change_priority:  change the priority of a swap device.
298 */
299void
300change_priority(char *path)
301{
302
303	if (swapctl(SWAP_CTL, path, pri) == -1)
304		warn("%s", path);
305}
306
307/*
308 * add_swap:  add the pathname to the list of swap devices.
309 */
310void
311add_swap(char *path)
312{
313
314	if (swapctl(SWAP_ON, path, pri) == -1)
315		if (errno != EBUSY)
316			err(1, "%s", path);
317}
318
319/*
320 * del_swap:  remove the pathname from the list of swap devices.
321 */
322void
323del_swap(char *path)
324{
325
326	if (swapctl(SWAP_OFF, path, pri) == -1)
327		err(1, "%s", path);
328}
329
330void
331do_fstab(void)
332{
333	struct	fstab *fp;
334	char	*s;
335	long	priority;
336	struct	stat st;
337	mode_t	rejecttype;
338	int	gotone = 0;
339
340	/*
341	 * Select which mount point types to reject, depending on the
342	 * value of the -t parameter.
343	 */
344	if (tflag != NULL) {
345		if (strcmp(tflag, "blk") == 0)
346			rejecttype = S_IFREG;
347		else if (strcmp(tflag, "noblk") == 0)
348			rejecttype = S_IFBLK;
349	} else
350		rejecttype = 0;
351
352#define PRIORITYEQ	"priority="
353#define NFSMNTPT	"nfsmntpt="
354#define PATH_MOUNT	"/sbin/mount_nfs"
355	while ((fp = getfsent()) != NULL) {
356		const char *spec;
357
358		if (strcmp(fp->fs_type, "sw") != 0)
359			continue;
360
361		spec = fp->fs_spec;
362
363		if ((s = strstr(fp->fs_mntops, PRIORITYEQ)) != NULL) {
364			s += sizeof(PRIORITYEQ) - 1;
365			priority = atol(s);
366		} else
367			priority = pri;
368
369		if ((s = strstr(fp->fs_mntops, NFSMNTPT)) != NULL) {
370			char *t;
371			pid_t pid;
372			int status;
373
374			/*
375			 * Skip this song and dance if we're only
376			 * doing block devices.
377			 */
378			if (rejecttype == S_IFREG)
379				continue;
380
381			t = strpbrk(s, ",");
382			if (t != 0)
383				*t = '\0';
384			spec = strdup(s + strlen(NFSMNTPT));
385			if (spec == NULL)
386				err(1, "strdup");
387
388			if (t != 0)
389				*t = ',';
390
391			if (strlen(spec) == 0) {
392				warnx("empty mountpoint");
393				free((char *)spec);
394				continue;
395			}
396
397			switch (pid = vfork()) {
398			case -1:	/* error */
399				err(1, "vfork");
400			case 0:
401				execl(PATH_MOUNT, PATH_MOUNT, fp->fs_spec, spec,
402				    (char *)NULL);
403				err(1, "execl");
404			}
405			while (waitpid(pid, &status, 0) == -1)
406				if (errno != EINTR)
407					err(1, "waitpid");
408			if (status != 0) {
409				warnx("%s: mount failed", fp->fs_spec);
410				free((char *)spec);
411				continue;
412			}
413		} else if (isduid(spec, 0)) {
414			if (rejecttype == S_IFBLK)
415				continue;
416		} else {
417			/*
418			 * Determine blk-ness.  Don't even consider a
419			 * mountpoint outside /dev as a block device.
420			 */
421			if (rejecttype == S_IFREG) {
422				if (strncmp("/dev/", spec, 5) != 0)
423					continue;
424			}
425			if (stat(spec, &st) == -1) {
426				warn("%s", spec);
427				continue;
428			}
429			if ((st.st_mode & S_IFMT) == rejecttype)
430				continue;
431
432			/*
433			 * Do not allow fancy objects to be swap areas.
434			 */
435			if (!S_ISREG(st.st_mode) &&
436			    !S_ISBLK(st.st_mode))
437				continue;
438		}
439
440		if (swapctl(SWAP_ON, spec, (int)priority) == -1) {
441			if (errno != EBUSY)
442				warn("%s", spec);
443		} else {
444			gotone = 1;
445			printf("%s: adding %s as swap device at priority %d\n",
446			    __progname, fp->fs_spec, (int)priority);
447		}
448
449		if (spec != fp->fs_spec)
450			free((char *)spec);
451	}
452	if (gotone == 0)
453		exit(1);
454}
455
456void
457usage(void)
458{
459
460	fprintf(stderr, "usage: %s -A [-p priority] [-t blk | noblk]\n",
461	    __progname);
462	fprintf(stderr, "       %s -a [-p priority] path\n", __progname);
463	fprintf(stderr, "       %s -c -p priority path\n", __progname);
464	fprintf(stderr, "       %s -d path\n", __progname);
465	fprintf(stderr, "       %s [[-l] | -s] [-k]\n", __progname);
466	exit(1);
467}
468