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 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 * 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 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 140 zonecfg_close_scratch(FILE *fp) 141 { 142 (void) fclose(fp); 143 } 144 145 int 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 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 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 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 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 263 zonecfg_is_scratch(const char *kernzone) 264 { 265 return (strncmp(kernzone, "SUNWlu", 6) == 0); 266 } 267