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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /*
28 * This module contains functions used for reading and writing the scratch zone
29 * translation files. These files are used by Live Upgrade to keep track of
30 * mappings between actual kernel zone names and the zones in an alternate boot
31 * environment.
32 *
33 * The functions are MT-safe.
34 *
35 * The file format looks like this:
36 *
37 * <zonename> <kernel-zonename> <alt-root>
38 *
39 * The expected usage model is:
40 *
41 * fp = zonecfg_open_scratch("", B_TRUE);
42 * zonecfg_lock_scratch(fp);
43 * if (zonecfg_find_scratch(fp, zonename, altroot, NULL, 0) == 0) {
44 * handle error; zone already mounted
45 * }
46 * mount zone here
47 * zonecfg_add_scratch(fp, zonename, kernname, altroot);
48 * zonecfg_close_scratch(fp);
49 * fp = zonecfg_open_scratch(zoneroot, B_TRUE);
50 * ftruncate(fileno(fp), 0);
51 * zonecfg_add_scratch(fp, zonename, kernname, "/");
52 * zonecfg_close_scratch(fp);
53 */
54
55 #include <stdio.h>
56 #include <unistd.h>
57 #include <fcntl.h>
58 #include <errno.h>
59 #include <string.h>
60 #include <sys/types.h>
61 #include <sys/stat.h>
62 #include <sys/param.h>
63 #include <libzonecfg.h>
64
65 #define PATH_MAPFILE "tmp/.alt.lu-zone-map"
66
67 static int
lock_op(int fd,int type)68 lock_op(int fd, int type)
69 {
70 struct flock lock;
71
72 lock.l_type = type;
73 lock.l_whence = SEEK_SET;
74 lock.l_start = 0;
75 lock.l_len = 0;
76
77 return (fcntl(fd, F_SETLKW, &lock));
78 }
79
80 FILE *
zonecfg_open_scratch(const char * rootpath,boolean_t createfile)81 zonecfg_open_scratch(const char *rootpath, boolean_t createfile)
82 {
83 mode_t oldmask = umask(0);
84 struct stat lbuf, fbuf;
85 int fd, flags;
86 FILE *fp;
87 char mapfile[MAXPATHLEN];
88
89 (void) snprintf(mapfile, sizeof (mapfile), "%s/" PATH_MAPFILE,
90 rootpath);
91
92 flags = O_RDWR | O_NOFOLLOW | O_NOLINKS;
93 if (createfile)
94 flags |= O_EXCL | O_CREAT;
95 if ((fd = open(mapfile, flags, 0644)) == -1) {
96 if (!createfile) {
97 errno = ENOENT;
98 goto failure;
99 }
100 if (lstat(mapfile, &lbuf) == -1)
101 goto failure;
102 if (!S_ISREG(lbuf.st_mode) || lbuf.st_nlink != 1 ||
103 lbuf.st_uid != 0) {
104 errno = EINVAL;
105 goto failure;
106 }
107 fd = open(mapfile, O_RDWR);
108 if (fd == -1)
109 goto failure;
110 if (fstat(fd, &fbuf) == -1)
111 goto failure;
112 if (lbuf.st_ino != fbuf.st_ino || lbuf.st_dev != fbuf.st_dev) {
113 errno = EINVAL;
114 goto failure;
115 }
116 }
117 if (lock_op(fd, F_RDLCK) == -1)
118 goto failure;
119 (void) umask(oldmask);
120 if ((fp = fdopen(fd, "r+")) == NULL)
121 (void) close(fd);
122 return (fp);
123
124 failure:
125 if (fd != -1)
126 (void) close(fd);
127 (void) umask(oldmask);
128 return (NULL);
129 }
130
131 int
zonecfg_lock_scratch(FILE * fp)132 zonecfg_lock_scratch(FILE *fp)
133 {
134 if (fflush(fp) != 0)
135 return (-1);
136 return (lock_op(fileno(fp), F_WRLCK));
137 }
138
139 void
zonecfg_close_scratch(FILE * fp)140 zonecfg_close_scratch(FILE *fp)
141 {
142 (void) fclose(fp);
143 }
144
145 int
zonecfg_get_scratch(FILE * fp,char * zonename,size_t namelen,char * kernname,size_t kernlen,char * altroot,size_t altlen)146 zonecfg_get_scratch(FILE *fp, char *zonename, size_t namelen, char *kernname,
147 size_t kernlen, char *altroot, size_t altlen)
148 {
149 char line[2 * ZONENAME_MAX + MAXPATHLEN + 2];
150 char *cp, *cp2;
151
152 /* We always hold at least a read lock on the file */
153 for (;;) {
154 if (fgets(line, sizeof (line), fp) == NULL)
155 return (-1);
156 if ((cp = strchr(line, '\n')) == NULL)
157 return (-1);
158 *cp = '\0';
159 if ((cp = strchr(line, ' ')) == NULL)
160 cp = line + strlen(line);
161 else
162 *cp++ = '\0';
163 if (zonename != NULL &&
164 strlcpy(zonename, line, namelen) >= namelen)
165 continue;
166 if ((cp2 = strchr(cp, ' ')) == NULL)
167 cp2 = cp + strlen(cp);
168 else
169 *cp2++ = '\0';
170 if (kernname != NULL &&
171 strlcpy(kernname, cp, kernlen) >= kernlen)
172 continue;
173 if (altroot != NULL && strlcpy(altroot, cp2, altlen) >= altlen)
174 continue;
175 break;
176 }
177 return (0);
178 }
179
180 int
zonecfg_find_scratch(FILE * fp,const char * zonename,const char * altroot,char * kernzone,size_t kernlen)181 zonecfg_find_scratch(FILE *fp, const char *zonename, const char *altroot,
182 char *kernzone, size_t kernlen)
183 {
184 char zone[ZONENAME_MAX];
185 char aroot[MAXPATHLEN];
186
187 rewind(fp);
188 while (zonecfg_get_scratch(fp, zone, sizeof (zone), kernzone, kernlen,
189 aroot, sizeof (aroot)) == 0) {
190 if (strcmp(zone, zonename) == 0 && strcmp(altroot, aroot) == 0)
191 return (0);
192 }
193 return (-1);
194 }
195
196 int
zonecfg_reverse_scratch(FILE * fp,const char * kernzone,char * zonename,size_t namelen,char * altroot,size_t altlen)197 zonecfg_reverse_scratch(FILE *fp, const char *kernzone, char *zonename,
198 size_t namelen, char *altroot, size_t altlen)
199 {
200 char kzone[ZONENAME_MAX];
201
202 rewind(fp);
203 while (zonecfg_get_scratch(fp, zonename, namelen, kzone,
204 sizeof (kzone), altroot, altlen) == 0) {
205 if (strcmp(kzone, kernzone) == 0)
206 return (0);
207 }
208 return (-1);
209 }
210
211 int
zonecfg_add_scratch(FILE * fp,const char * zonename,const char * kernzone,const char * altroot)212 zonecfg_add_scratch(FILE *fp, const char *zonename, const char *kernzone,
213 const char *altroot)
214 {
215 if (fseek(fp, 0, SEEK_END) == -1)
216 return (-1);
217 if (fprintf(fp, "%s %s %s\n", zonename, kernzone, altroot) == EOF)
218 return (-1);
219 if (fflush(fp) != 0)
220 return (-1);
221 return (0);
222 }
223
224 int
zonecfg_delete_scratch(FILE * fp,const char * kernzone)225 zonecfg_delete_scratch(FILE *fp, const char *kernzone)
226 {
227 char zone[ZONENAME_MAX];
228 char kzone[ZONENAME_MAX];
229 char aroot[MAXPATHLEN];
230 long roffs, woffs;
231
232 /*
233 * The implementation here is intentionally quite simple. We could
234 * allocate a buffer that's big enough to hold the data up to
235 * stat.st_size and then write back out the part we need to, but there
236 * seems to be little point.
237 */
238 rewind(fp);
239 roffs = 0;
240 do {
241 woffs = roffs;
242 if (zonecfg_get_scratch(fp, NULL, 0, kzone, sizeof (kzone),
243 NULL, 0) != 0)
244 return (-1);
245 roffs = ftell(fp);
246 } while (strcmp(kzone, kernzone) != 0);
247 while (zonecfg_get_scratch(fp, zone, sizeof (zone), kzone,
248 sizeof (kzone), aroot, sizeof aroot) == 0) {
249 roffs = ftell(fp);
250 if (fseek(fp, woffs, SEEK_SET) == -1)
251 break;
252 if (fprintf(fp, "%s %s %s\n", zone, kzone, aroot) == EOF)
253 break;
254 woffs = ftell(fp);
255 if (fseek(fp, roffs, SEEK_SET) == -1)
256 break;
257 }
258 (void) ftruncate(fileno(fp), woffs);
259 return (0);
260 }
261
262 boolean_t
zonecfg_is_scratch(const char * kernzone)263 zonecfg_is_scratch(const char *kernzone)
264 {
265 return (strncmp(kernzone, "SUNWlu", 6) == 0);
266 }
267