xref: /illumos-gate/usr/src/lib/libdevid/deviceid.c (revision 8b80e8cb6855118d46f605e91b5ed4ce83417395)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include <unistd.h>
29 #include <stdlib.h>
30 #include <errno.h>
31 #include <ftw.h>
32 #include <string.h>
33 #include <thread.h>
34 #include <synch.h>
35 #include <sys/types.h>
36 #include <sys/stat.h>
37 #include <fcntl.h>
38 #include <sys/modctl.h>
39 #include <strings.h>
40 
41 #include <libdevinfo.h>
42 #include "libdevid.h"
43 
44 /*
45  * Get Device Id from an open file descriptor
46  */
47 int
48 devid_get(int fd, ddi_devid_t *devidp)
49 {
50 	int		len = 0;
51 	dev_t		dev;
52 	struct stat	statb;
53 	ddi_devid_t	mydevid;
54 
55 	if (fstat(fd, &statb) != 0)
56 		return (-1);
57 
58 	/* If not char or block device, then error */
59 	if (!S_ISCHR(statb.st_mode) && !S_ISBLK(statb.st_mode))
60 		return (-1);
61 
62 	/* Get the device id size */
63 	dev = statb.st_rdev;
64 	if (modctl(MODSIZEOF_DEVID, dev, &len) != 0)
65 		return (-1);
66 
67 	/* Allocate space to return device id */
68 	if ((mydevid = (ddi_devid_t)malloc(len)) == NULL)
69 		return (-1);
70 
71 	/* Get the device id */
72 	if (modctl(MODGETDEVID, dev, len, mydevid) != 0) {
73 		free(mydevid);
74 		return (-1);
75 	}
76 
77 	/* Return the device id copy */
78 	*devidp = mydevid;
79 	return (0);
80 }
81 
82 /*
83  * Get the minor name
84  */
85 int
86 devid_get_minor_name(int fd, char **minor_namep)
87 {
88 	int		len = 0;
89 	dev_t		dev;
90 	int		spectype;
91 	char		*myminor_name;
92 	struct stat	statb;
93 
94 	if (fstat(fd, &statb) != 0)
95 		return (-1);
96 
97 	/* If not a char or block device, then return an error */
98 	if (!S_ISCHR(statb.st_mode) && !S_ISBLK(statb.st_mode))
99 		return (-1);
100 
101 	spectype = statb.st_mode & S_IFMT;
102 	dev = statb.st_rdev;
103 
104 	/* Get the minor name size */
105 	if (modctl(MODSIZEOF_MINORNAME, dev, spectype, &len) != 0)
106 		return (-1);
107 
108 	/* Allocate space for the minor name */
109 	if ((myminor_name = (char *)malloc(len)) == NULL)
110 		return (-1);
111 
112 	/* Get the minor name */
113 	if (modctl(MODGETMINORNAME, dev, spectype, len, myminor_name) != 0) {
114 		free(myminor_name);
115 		return (-1);
116 	}
117 
118 	/* return the minor name copy */
119 	*minor_namep = myminor_name;
120 	return (0);
121 }
122 
123 /* list element of devid_nmlist_t information */
124 struct nmlist {
125 	struct nmlist	*nl_next;
126 	char		*nl_devname;
127 	dev_t		nl_dev;
128 };
129 
130 /* add list element to end of nmlist headed by *nlhp */
131 struct nmlist *
132 nmlist_add(struct nmlist **nlhp, char *path)
133 {
134 	struct stat	statb;
135 	dev_t		dev;
136 	struct nmlist	*nl;
137 
138 	/* stat and get the devt for char or block */
139 	if ((stat(path, &statb) == 0) &&
140 	    (S_ISCHR(statb.st_mode) || S_ISBLK(statb.st_mode)))
141 		dev = statb.st_rdev;
142 	else
143 		dev = NODEV;
144 
145 	/* find the end of the list */
146 	for (; (nl = *nlhp) != NULL; nlhp = &nl->nl_next)
147 		;
148 
149 	/* allocate and initialize new entry */
150 	if ((nl = malloc(sizeof (*nl))) == NULL)
151 		return (NULL);
152 
153 	if ((nl->nl_devname = strdup(path)) == NULL) {
154 		free(nl);
155 		return (NULL);
156 	}
157 	nl->nl_next = NULL;
158 	nl->nl_dev = dev;
159 
160 	/* link new entry at end */
161 	*nlhp = nl;
162 	return (nl);
163 }
164 
165 /* information needed by devlink_callback to call nmlist_add */
166 struct devlink_cbinfo {
167 	struct nmlist	**cbi_nlhp;
168 	char		*cbi_search_path;
169 	int		cbi_error;
170 };
171 
172 /* di_devlink callback to add a /dev entry to nmlist */
173 static int
174 devlink_callback(di_devlink_t dl, void *arg)
175 {
176 	struct devlink_cbinfo	*cbip = (struct devlink_cbinfo *)arg;
177 	char			*devpath = (char *)di_devlink_path(dl);
178 
179 	if (strncmp(devpath, cbip->cbi_search_path,
180 	    strlen(cbip->cbi_search_path)) == 0) {
181 		if (nmlist_add(cbip->cbi_nlhp, devpath) == NULL) {
182 			cbip->cbi_error = 1;
183 			return (DI_WALK_TERMINATE);
184 		}
185 	}
186 	return (DI_WALK_CONTINUE);
187 }
188 
189 /*
190  * Resolve /dev names to DI_PRIMARY_LINK, DI_SECONDARY_LINK, or both.
191  * The default is to resolve to just the DI_PRIMARY_LINK.
192  */
193 int			devid_deviceid_to_nmlist_link = DI_PRIMARY_LINK;
194 
195 /*
196  * Options for the devid_deviceid_to_nmlist implementation:
197  *
198  *   DEVICEID_NMLIST_SLINK -	reduce overhead by reuse the previous
199  *				di_devlink_init.
200  */
201 #define	DEVICEID_NMLIST_SLINK	1
202 int			devid_deviceid_to_nmlist_flg = 0;
203 static di_devlink_handle_t devid_deviceid_to_nmlist_dlh = NULL;	/* SLINK */
204 
205 #define	DEVICEID_NMLIST_NRETRY	10
206 
207 /*
208  * Convert the specified devid/minor_name into a devid_nmlist_t array
209  * with names that resolve into /devices or /dev depending on search_path.
210  *
211  * The man page indicates that:
212  *
213  *     This function traverses the file tree, starting at search_path.
214  *
215  * This is not true, we reverse engineer the paths relative to
216  * the specified search path to avoid attaching all devices.
217  */
218 int
219 devid_deviceid_to_nmlist(
220 	char		*search_path,
221 	ddi_devid_t	devid,
222 	char		*minor_name,
223 	devid_nmlist_t	**retlist)
224 {
225 	char			*cp;
226 	int			dev;
227 	char			*paths = NULL;
228 	char			*path;
229 	int			lens;
230 	di_devlink_handle_t	dlh = NULL;
231 	int			ret = -1;
232 	struct devlink_cbinfo	cbi;
233 	struct nmlist		*nlh = NULL;
234 	struct nmlist		*nl;
235 	devid_nmlist_t		*rl;
236 	int			nret;
237 	int			nagain = 0;
238 	int			err = 0;
239 
240 	*retlist = NULL;
241 
242 	/* verify valid search path starts with "/devices" or "/dev" */
243 	if ((strcmp(search_path, "/devices") == 0) ||
244 	    (strncmp(search_path, "/devices/", 9) == 0))
245 		dev = 0;
246 	else if ((strcmp(search_path, "/dev") == 0) ||
247 	    (strncmp(search_path, "/dev/", 5) == 0))
248 		dev = 1;
249 	else {
250 		errno = EINVAL;
251 		return (-1);
252 	}
253 
254 
255 	/* translate devid/minor_name to /devices paths */
256 again:	if (modctl(MODDEVID2PATHS, devid, minor_name, 0, &lens, NULL) != 0)
257 		goto out;
258 	if ((paths = (char *)malloc(lens)) == NULL)
259 		goto out;
260 	if (modctl(MODDEVID2PATHS, devid, minor_name, 0, &lens, paths) != 0) {
261 		if ((errno == EAGAIN) && (nagain++ < DEVICEID_NMLIST_NRETRY)) {
262 			free(paths);
263 			paths = NULL;
264 			goto again;
265 		}
266 		goto out;
267 	}
268 
269 	/*
270 	 * initialize for /devices path to /dev path translation. To reduce
271 	 * overhead we reuse the last snapshot if DEVICEID_NMLIST_SLINK is set.
272 	 */
273 	if (dev) {
274 		dlh = devid_deviceid_to_nmlist_dlh;
275 		if (dlh &&
276 		    !(devid_deviceid_to_nmlist_flg & DEVICEID_NMLIST_SLINK)) {
277 			(void) di_devlink_fini(&dlh);
278 			dlh = devid_deviceid_to_nmlist_dlh = NULL;
279 		}
280 		if ((dlh == NULL) &&
281 		    ((dlh = di_devlink_init(NULL, 0)) == NULL))
282 				goto out;
283 	}
284 
285 	/*
286 	 * iterate over all the devtspectype resolutions of the devid and
287 	 * convert them into the appropriate path form and add items to return
288 	 * to the nmlist list;
289 	 */
290 	for (path = paths; *path; path += strlen(path) + 1) {
291 		if (dev) {
292 			/* add /dev entries */
293 			cbi.cbi_nlhp = &nlh;
294 			cbi.cbi_search_path = search_path;
295 			cbi.cbi_error = 0;
296 
297 			(void) di_devlink_walk(dlh, NULL, path,
298 			    devid_deviceid_to_nmlist_link,
299 			    (void *)&cbi, devlink_callback);
300 			if (cbi.cbi_error)
301 				goto out;
302 		} else {
303 			/* add /devices entry */
304 			cp = malloc(strlen("/devices") + strlen(path) + 1);
305 			(void) strcpy(cp, "/devices");
306 			(void) strcat(cp, path);
307 			if (strncmp(cp, search_path,
308 			    strlen(search_path)) == 0) {
309 				if (nmlist_add(&nlh, cp) == NULL) {
310 					free(cp);
311 					goto out;
312 				}
313 			}
314 			free(cp);
315 		}
316 	}
317 
318 	/* convert from nmlist to retlist array */
319 	for (nl = nlh, nret = 0; nl; nl = nl->nl_next)
320 		nret++;
321 	if (nret == 0) {
322 		err = ENODEV;
323 		goto out;
324 	}
325 	if ((*retlist = calloc(nret + 1, sizeof (devid_nmlist_t))) == NULL) {
326 		err = ENOMEM;
327 		goto out;
328 	}
329 	for (nl = nlh, rl = *retlist; nl; nl = nl->nl_next, rl++) {
330 		rl->devname = nl->nl_devname;
331 		rl->dev = nl->nl_dev;
332 	}
333 	rl->devname = NULL;
334 	rl->dev = NODEV;
335 
336 	ret = 0;
337 
338 out:
339 	while ((nl = nlh) != NULL) {	/* free the nmlist */
340 		nlh = nl->nl_next;
341 		free(nl);
342 	}
343 	if (paths)
344 		free(paths);
345 	if (dlh) {
346 		if ((ret == 0) &&
347 		    (devid_deviceid_to_nmlist_flg & DEVICEID_NMLIST_SLINK))
348 			devid_deviceid_to_nmlist_dlh = dlh;
349 		else
350 			(void) di_devlink_fini(&dlh);
351 	}
352 	if (ret && *retlist)
353 		free(*retlist);
354 	if (ret && err != 0)
355 		errno = err;
356 	return (ret);
357 }
358 
359 /*
360  * Free Device Id Name List
361  */
362 void
363 devid_free_nmlist(devid_nmlist_t *list)
364 {
365 	devid_nmlist_t *p = list;
366 
367 	if (list == NULL)
368 		return;
369 
370 	/* Free all the device names */
371 	while (p->devname != NULL) {
372 		free(p->devname);
373 		p++;
374 	}
375 
376 	/* Free the array */
377 	free(list);
378 }
379