swapctl.c revision 1.20 
1/*	$OpenBSD: swapctl.c,v 1.20 2015/04/18 18:28:37 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
56#include <unistd.h>
57#include <err.h>
58#include <errno.h>
59#include <stdio.h>
60#include <stdlib.h>
61#include <limits.h>
62#include <string.h>
63#include <fstab.h>
64#include <util.h>
65
66#include "swapctl.h"
67
68int	command;
69
70/*
71 * Commands for swapctl(8).  These are mutually exclusive.
72 */
73#define	CMD_A		0x01	/* process /etc/fstab */
74#define	CMD_a		0x02	/* add a swap file/device */
75#define	CMD_c		0x04	/* change priority of a swap file/device */
76#define	CMD_d		0x08	/* delete a swap file/device */
77#define	CMD_l		0x10	/* list swap files/devices */
78#define	CMD_s		0x20	/* summary of swap files/devices */
79
80#define	SET_COMMAND(cmd) \
81do { \
82	if (command) \
83		usage(); \
84	command = (cmd); \
85} while (0)
86
87/*
88 * Commands that require a "path" argument at the end of the command
89 * line, and the ones which require that none exist.
90 */
91#define	REQUIRE_PATH	(CMD_a | CMD_c | CMD_d)
92#define	REQUIRE_NOPATH	(CMD_A | CMD_l | CMD_s)
93
94/*
95 * Option flags, and the commands with which they are valid.
96 */
97int	kflag;		/* display in 1K blocks */
98#define	KFLAG_CMDS	(CMD_l | CMD_s)
99
100int	pflag;		/* priority was specified */
101#define	PFLAG_CMDS	(CMD_A | CMD_a | CMD_c)
102
103char	*tflag;		/* swap device type (blk or noblk) */
104#define	TFLAG_CMDS	(CMD_A)
105
106int	pri;		/* uses 0 as default pri */
107
108static	void change_priority(char *);
109static	void add_swap(char *);
110static	void del_swap(char *);
111static	void do_fstab(void);
112static	void usage(void);
113static	int  swapon_command(int, char **);
114
115extern	char *__progname;	/* from crt0.o */
116
117int
118main(int argc, char *argv[])
119{
120	const char *errstr;
121	int	c;
122
123	if (strcmp(__progname, "swapon") == 0)
124		return swapon_command(argc, argv);
125
126	while ((c = getopt(argc, argv, "Aacdlkp:st:")) != -1) {
127		switch (c) {
128		case 'A':
129			SET_COMMAND(CMD_A);
130			break;
131
132		case 'a':
133			SET_COMMAND(CMD_a);
134			break;
135
136		case 'c':
137			SET_COMMAND(CMD_c);
138			break;
139
140		case 'd':
141			SET_COMMAND(CMD_d);
142			break;
143
144		case 'l':
145			SET_COMMAND(CMD_l);
146			break;
147
148		case 'k':
149			kflag = 1;
150			break;
151
152		case 'p':
153			pflag = 1;
154			pri = strtonum(optarg, 0, INT_MAX, &errstr);
155			if (errstr)
156				errx(1, "-p %s: %s", errstr, optarg);
157			break;
158
159		case 's':
160			SET_COMMAND(CMD_s);
161			break;
162
163		case 't':
164			if (tflag != NULL)
165				usage();
166			tflag = optarg;
167			break;
168
169		default:
170			usage();
171			/* NOTREACHED */
172		}
173	}
174
175	argv += optind;
176	argc -= optind;
177
178	/* Did the user specify a command? */
179	if (command == 0) {
180		if (argc == 0)
181			SET_COMMAND(CMD_l);
182		else
183			usage();
184	}
185
186	switch (argc) {
187	case 0:
188		if (command & REQUIRE_PATH)
189			usage();
190		break;
191
192	case 1:
193		if (command & REQUIRE_NOPATH)
194			usage();
195		break;
196
197	default:
198		usage();
199	}
200
201	/* To change priority, you have to specify one. */
202	if ((command == CMD_c) && pflag == 0)
203		usage();
204
205	/* Sanity-check -t */
206	if (tflag != NULL) {
207		if (command != CMD_A)
208			usage();
209		if (strcmp(tflag, "blk") != 0 &&
210		    strcmp(tflag, "noblk") != 0)
211			usage();
212	}
213
214	/* Dispatch the command. */
215	switch (command) {
216	case CMD_l:
217		list_swap(pri, kflag, pflag, 1);
218		break;
219
220	case CMD_s:
221		list_swap(pri, kflag, pflag, 0);
222		break;
223
224	case CMD_c:
225		change_priority(argv[0]);
226		break;
227
228	case CMD_a:
229		add_swap(argv[0]);
230		break;
231
232	case CMD_d:
233		del_swap(argv[0]);
234		break;
235
236	case CMD_A:
237		do_fstab();
238		break;
239	}
240
241	return (0);
242}
243
244/*
245 * swapon_command: emulate the old swapon(8) program.
246 */
247int
248swapon_command(int argc, char **argv)
249{
250	int ch, fiztab = 0;
251
252	while ((ch = getopt(argc, argv, "at:")) != -1) {
253		switch (ch) {
254		case 'a':
255			fiztab = 1;
256			break;
257		case 't':
258			if (tflag != NULL)
259				usage();
260			tflag = optarg;
261			break;
262		default:
263			goto swapon_usage;
264		}
265	}
266	argc -= optind;
267	argv += optind;
268
269	if (fiztab) {
270		if (argc)
271			goto swapon_usage;
272		/* Sanity-check -t */
273		if (tflag != NULL) {
274			if (strcmp(tflag, "blk") != 0 &&
275			    strcmp(tflag, "noblk") != 0)
276				usage();
277		}
278		do_fstab();
279		return (0);
280	} else if (argc == 0 || tflag != NULL)
281		goto swapon_usage;
282
283	while (argc) {
284		add_swap(argv[0]);
285		argc--;
286		argv++;
287	}
288	return (0);
289
290 swapon_usage:
291	fprintf(stderr, "usage: %s -a | path\n", __progname);
292	return (1);
293}
294
295/*
296 * change_priority:  change the priority of a swap device.
297 */
298void
299change_priority(char *path)
300{
301
302	if (swapctl(SWAP_CTL, path, pri) < 0)
303		warn("%s", path);
304}
305
306/*
307 * add_swap:  add the pathname to the list of swap devices.
308 */
309void
310add_swap(char *path)
311{
312
313	if (swapctl(SWAP_ON, path, pri) < 0)
314		if (errno != EBUSY)
315			err(1, "%s", path);
316}
317
318/*
319 * del_swap:  remove the pathname from the list of swap devices.
320 */
321void
322del_swap(char *path)
323{
324
325	if (swapctl(SWAP_OFF, path, pri) < 0)
326		err(1, "%s", path);
327}
328
329void
330do_fstab(void)
331{
332	struct	fstab *fp;
333	char	*s;
334	long	priority;
335	struct	stat st;
336	mode_t	rejecttype;
337	int	gotone = 0;
338
339	/*
340	 * Select which mount point types to reject, depending on the
341	 * value of the -t parameter.
342	 */
343	if (tflag != NULL) {
344		if (strcmp(tflag, "blk") == 0)
345			rejecttype = S_IFREG;
346		else if (strcmp(tflag, "noblk") == 0)
347			rejecttype = S_IFBLK;
348	} else
349		rejecttype = 0;
350
351#define PRIORITYEQ	"priority="
352#define NFSMNTPT	"nfsmntpt="
353#define PATH_MOUNT	"/sbin/mount_nfs"
354	while ((fp = getfsent()) != NULL) {
355		const char *spec;
356
357		if (strcmp(fp->fs_type, "sw") != 0)
358			continue;
359
360		spec = fp->fs_spec;
361
362		if ((s = strstr(fp->fs_mntops, PRIORITYEQ)) != NULL) {
363			s += sizeof(PRIORITYEQ) - 1;
364			priority = atol(s);
365		} else
366			priority = pri;
367
368		if ((s = strstr(fp->fs_mntops, NFSMNTPT)) != NULL) {
369			char *t, cmd[sizeof(PATH_MOUNT)+PATH_MAX+1+PATH_MAX+1];
370			int l;
371
372			/*
373			 * Skip this song and dance if we're only
374			 * doing block devices.
375			 */
376			if (rejecttype == S_IFREG)
377				continue;
378
379			t = strpbrk(s, ",");
380			if (t != 0)
381				*t = '\0';
382			spec = strdup(s + strlen(NFSMNTPT));
383			if (spec == NULL)
384				err(1, "strdup");
385
386			if (t != 0)
387				*t = ',';
388
389			if (strlen(spec) == 0) {
390				warnx("empty mountpoint");
391				free((char *)spec);
392				continue;
393			}
394			l = snprintf(cmd, sizeof(cmd), "%s %s %s",
395			    PATH_MOUNT, fp->fs_spec, spec);
396			if (l == -1 || l >= sizeof(cmd))
397				errx(1, "path too long");
398			if (system(cmd) != 0) {
399				warnx("%s: mount failed", fp->fs_spec);
400				free((char *)spec);
401				continue;
402			}
403		} else if (isduid(spec, 0)) {
404			if (rejecttype == S_IFBLK)
405				continue;
406		} else {
407			/*
408			 * Determine blk-ness.  Don't even consider a
409			 * mountpoint outside /dev as a block device.
410			 */
411			if (rejecttype == S_IFREG) {
412				if (strncmp("/dev/", spec, 5) != 0)
413					continue;
414			}
415			if (stat(spec, &st) < 0) {
416				warn("%s", spec);
417				continue;
418			}
419			if ((st.st_mode & S_IFMT) == rejecttype)
420				continue;
421
422			/*
423			 * Do not allow fancy objects to be swap areas.
424			 */
425			if (!S_ISREG(st.st_mode) &&
426			    !S_ISBLK(st.st_mode))
427				continue;
428		}
429
430		if (swapctl(SWAP_ON, spec, (int)priority) < 0) {
431			if (errno != EBUSY)
432				warn("%s", spec);
433		} else {
434			gotone = 1;
435			printf("%s: adding %s as swap device at priority %d\n",
436			    __progname, fp->fs_spec, (int)priority);
437		}
438
439		if (spec != fp->fs_spec)
440			free((char *)spec);
441	}
442	if (gotone == 0)
443		exit(1);
444}
445
446void
447usage(void)
448{
449
450	fprintf(stderr, "usage: %s -A [-p priority] [-t blk|noblk]\n",
451	    __progname);
452	fprintf(stderr, "       %s -a [-p priority] path\n", __progname);
453	fprintf(stderr, "       %s -c -p priority path\n", __progname);
454	fprintf(stderr, "       %s -d path\n", __progname);
455	fprintf(stderr, "       %s [[-l] | -s] [-k]\n", __progname);
456	exit(1);
457}
458