Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * srm_env.c - Access to SRM environment |
| 3 | * variables through linux' procfs |
| 4 | * |
| 5 | * Copyright (C) 2001-2002 Jan-Benedict Glaw <jbglaw@lug-owl.de> |
| 6 | * |
| 7 | * This driver is at all a modified version of Erik Mouw's |
| 8 | * Documentation/DocBook/procfs_example.c, so: thank |
| 9 | * you, Erik! He can be reached via email at |
| 10 | * <J.A.K.Mouw@its.tudelft.nl>. It is based on an idea |
| 11 | * provided by DEC^WCompaq^WIntel's "Jumpstart" CD. They |
| 12 | * included a patch like this as well. Thanks for idea! |
| 13 | * |
| 14 | * This program is free software; you can redistribute |
| 15 | * it and/or modify it under the terms of the GNU General |
| 16 | * Public License version 2 as published by the Free Software |
| 17 | * Foundation. |
| 18 | * |
| 19 | * This program is distributed in the hope that it will be |
| 20 | * useful, but WITHOUT ANY WARRANTY; without even the implied |
| 21 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE. See the GNU General Public License for more |
| 23 | * details. |
| 24 | * |
| 25 | * You should have received a copy of the GNU General Public |
| 26 | * License along with this program; if not, write to the |
| 27 | * Free Software Foundation, Inc., 59 Temple Place, |
| 28 | * Suite 330, Boston, MA 02111-1307 USA |
| 29 | * |
| 30 | */ |
| 31 | |
| 32 | /* |
| 33 | * Changelog |
| 34 | * ~~~~~~~~~ |
| 35 | * |
| 36 | * Thu, 22 Aug 2002 15:10:43 +0200 |
| 37 | * - Update Config.help entry. I got a number of emails asking |
| 38 | * me to tell their senders if they could make use of this |
| 39 | * piece of code... So: "SRM is something like BIOS for your |
| 40 | * Alpha" |
| 41 | * - Update code formatting a bit to better conform CodingStyle |
| 42 | * rules. |
| 43 | * - So this is v0.0.5, with no changes (except formatting) |
| 44 | * |
| 45 | * Wed, 22 May 2002 00:11:21 +0200 |
| 46 | * - Fix typo on comment (SRC -> SRM) |
| 47 | * - Call this "Version 0.0.4" |
| 48 | * |
| 49 | * Tue, 9 Apr 2002 18:44:40 +0200 |
| 50 | * - Implement access by variable name and additionally |
| 51 | * by number. This is done by creating two subdirectories |
| 52 | * where one holds all names (like the old directory |
| 53 | * did) and the other holding 256 files named like "0", |
| 54 | * "1" and so on. |
| 55 | * - Call this "Version 0.0.3" |
| 56 | * |
| 57 | */ |
| 58 | |
| 59 | #include <linux/kernel.h> |
| 60 | #include <linux/config.h> |
| 61 | #include <linux/module.h> |
| 62 | #include <linux/init.h> |
| 63 | #include <linux/proc_fs.h> |
| 64 | #include <asm/console.h> |
| 65 | #include <asm/uaccess.h> |
| 66 | #include <asm/machvec.h> |
| 67 | |
| 68 | #define BASE_DIR "srm_environment" /* Subdir in /proc/ */ |
| 69 | #define NAMED_DIR "named_variables" /* Subdir for known variables */ |
| 70 | #define NUMBERED_DIR "numbered_variables" /* Subdir for all variables */ |
| 71 | #define VERSION "0.0.5" /* Module version */ |
| 72 | #define NAME "srm_env" /* Module name */ |
| 73 | |
| 74 | MODULE_AUTHOR("Jan-Benedict Glaw <jbglaw@lug-owl.de>"); |
| 75 | MODULE_DESCRIPTION("Accessing Alpha SRM environment through procfs interface"); |
| 76 | MODULE_LICENSE("GPL"); |
| 77 | |
| 78 | typedef struct _srm_env { |
| 79 | char *name; |
| 80 | unsigned long id; |
| 81 | struct proc_dir_entry *proc_entry; |
| 82 | } srm_env_t; |
| 83 | |
| 84 | static struct proc_dir_entry *base_dir; |
| 85 | static struct proc_dir_entry *named_dir; |
| 86 | static struct proc_dir_entry *numbered_dir; |
| 87 | static char number[256][4]; |
| 88 | |
| 89 | static srm_env_t srm_named_entries[] = { |
| 90 | { "auto_action", ENV_AUTO_ACTION }, |
| 91 | { "boot_dev", ENV_BOOT_DEV }, |
| 92 | { "bootdef_dev", ENV_BOOTDEF_DEV }, |
| 93 | { "booted_dev", ENV_BOOTED_DEV }, |
| 94 | { "boot_file", ENV_BOOT_FILE }, |
| 95 | { "booted_file", ENV_BOOTED_FILE }, |
| 96 | { "boot_osflags", ENV_BOOT_OSFLAGS }, |
| 97 | { "booted_osflags", ENV_BOOTED_OSFLAGS }, |
| 98 | { "boot_reset", ENV_BOOT_RESET }, |
| 99 | { "dump_dev", ENV_DUMP_DEV }, |
| 100 | { "enable_audit", ENV_ENABLE_AUDIT }, |
| 101 | { "license", ENV_LICENSE }, |
| 102 | { "char_set", ENV_CHAR_SET }, |
| 103 | { "language", ENV_LANGUAGE }, |
| 104 | { "tty_dev", ENV_TTY_DEV }, |
| 105 | { NULL, 0 }, |
| 106 | }; |
| 107 | static srm_env_t srm_numbered_entries[256]; |
| 108 | |
| 109 | |
| 110 | |
| 111 | static int |
| 112 | srm_env_read(char *page, char **start, off_t off, int count, int *eof, |
| 113 | void *data) |
| 114 | { |
| 115 | int nbytes; |
| 116 | unsigned long ret; |
| 117 | srm_env_t *entry; |
| 118 | |
| 119 | if(off != 0) |
| 120 | return -EFAULT; |
| 121 | |
| 122 | entry = (srm_env_t *) data; |
| 123 | ret = callback_getenv(entry->id, page, count); |
| 124 | |
| 125 | if((ret >> 61) == 0) |
| 126 | nbytes = (int) ret; |
| 127 | else |
| 128 | nbytes = -EFAULT; |
| 129 | |
| 130 | return nbytes; |
| 131 | } |
| 132 | |
| 133 | |
| 134 | static int |
| 135 | srm_env_write(struct file *file, const char __user *buffer, unsigned long count, |
| 136 | void *data) |
| 137 | { |
| 138 | int res; |
| 139 | srm_env_t *entry; |
| 140 | char *buf = (char *) __get_free_page(GFP_USER); |
| 141 | unsigned long ret1, ret2; |
| 142 | |
| 143 | entry = (srm_env_t *) data; |
| 144 | |
| 145 | if (!buf) |
| 146 | return -ENOMEM; |
| 147 | |
| 148 | res = -EINVAL; |
| 149 | if (count >= PAGE_SIZE) |
| 150 | goto out; |
| 151 | |
| 152 | res = -EFAULT; |
| 153 | if (copy_from_user(buf, buffer, count)) |
| 154 | goto out; |
| 155 | buf[count] = '\0'; |
| 156 | |
| 157 | ret1 = callback_setenv(entry->id, buf, count); |
| 158 | if ((ret1 >> 61) == 0) { |
| 159 | do |
| 160 | ret2 = callback_save_env(); |
| 161 | while((ret2 >> 61) == 1); |
| 162 | res = (int) ret1; |
| 163 | } |
| 164 | |
| 165 | out: |
| 166 | free_page((unsigned long)buf); |
| 167 | return res; |
| 168 | } |
| 169 | |
| 170 | static void |
| 171 | srm_env_cleanup(void) |
| 172 | { |
| 173 | srm_env_t *entry; |
| 174 | unsigned long var_num; |
| 175 | |
| 176 | if(base_dir) { |
| 177 | /* |
| 178 | * Remove named entries |
| 179 | */ |
| 180 | if(named_dir) { |
| 181 | entry = srm_named_entries; |
| 182 | while(entry->name != NULL && entry->id != 0) { |
| 183 | if(entry->proc_entry) { |
| 184 | remove_proc_entry(entry->name, |
| 185 | named_dir); |
| 186 | entry->proc_entry = NULL; |
| 187 | } |
| 188 | entry++; |
| 189 | } |
| 190 | remove_proc_entry(NAMED_DIR, base_dir); |
| 191 | } |
| 192 | |
| 193 | /* |
| 194 | * Remove numbered entries |
| 195 | */ |
| 196 | if(numbered_dir) { |
| 197 | for(var_num = 0; var_num <= 255; var_num++) { |
| 198 | entry = &srm_numbered_entries[var_num]; |
| 199 | |
| 200 | if(entry->proc_entry) { |
| 201 | remove_proc_entry(entry->name, |
| 202 | numbered_dir); |
| 203 | entry->proc_entry = NULL; |
| 204 | entry->name = NULL; |
| 205 | } |
| 206 | } |
| 207 | remove_proc_entry(NUMBERED_DIR, base_dir); |
| 208 | } |
| 209 | |
| 210 | remove_proc_entry(BASE_DIR, NULL); |
| 211 | } |
| 212 | |
| 213 | return; |
| 214 | } |
| 215 | |
| 216 | |
| 217 | static int __init |
| 218 | srm_env_init(void) |
| 219 | { |
| 220 | srm_env_t *entry; |
| 221 | unsigned long var_num; |
| 222 | |
| 223 | /* |
| 224 | * Check system |
| 225 | */ |
| 226 | if(!alpha_using_srm) { |
| 227 | printk(KERN_INFO "%s: This Alpha system doesn't " |
| 228 | "know about SRM (or you've booted " |
| 229 | "SRM->MILO->Linux, which gets " |
| 230 | "misdetected)...\n", __FUNCTION__); |
| 231 | return -ENODEV; |
| 232 | } |
| 233 | |
| 234 | /* |
| 235 | * Init numbers |
| 236 | */ |
| 237 | for(var_num = 0; var_num <= 255; var_num++) |
| 238 | sprintf(number[var_num], "%ld", var_num); |
| 239 | |
| 240 | /* |
| 241 | * Create base directory |
| 242 | */ |
| 243 | base_dir = proc_mkdir(BASE_DIR, NULL); |
| 244 | if(base_dir == NULL) { |
| 245 | printk(KERN_ERR "Couldn't create base dir /proc/%s\n", |
| 246 | BASE_DIR); |
| 247 | goto cleanup; |
| 248 | } |
| 249 | base_dir->owner = THIS_MODULE; |
| 250 | |
| 251 | /* |
| 252 | * Create per-name subdirectory |
| 253 | */ |
| 254 | named_dir = proc_mkdir(NAMED_DIR, base_dir); |
| 255 | if(named_dir == NULL) { |
| 256 | printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n", |
| 257 | BASE_DIR, NAMED_DIR); |
| 258 | goto cleanup; |
| 259 | } |
| 260 | named_dir->owner = THIS_MODULE; |
| 261 | |
| 262 | /* |
| 263 | * Create per-number subdirectory |
| 264 | */ |
| 265 | numbered_dir = proc_mkdir(NUMBERED_DIR, base_dir); |
| 266 | if(numbered_dir == NULL) { |
| 267 | printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n", |
| 268 | BASE_DIR, NUMBERED_DIR); |
| 269 | goto cleanup; |
| 270 | |
| 271 | } |
| 272 | numbered_dir->owner = THIS_MODULE; |
| 273 | |
| 274 | /* |
| 275 | * Create all named nodes |
| 276 | */ |
| 277 | entry = srm_named_entries; |
| 278 | while(entry->name != NULL && entry->id != 0) { |
| 279 | entry->proc_entry = create_proc_entry(entry->name, |
| 280 | 0644, named_dir); |
| 281 | if(entry->proc_entry == NULL) |
| 282 | goto cleanup; |
| 283 | |
| 284 | entry->proc_entry->data = (void *) entry; |
| 285 | entry->proc_entry->owner = THIS_MODULE; |
| 286 | entry->proc_entry->read_proc = srm_env_read; |
| 287 | entry->proc_entry->write_proc = srm_env_write; |
| 288 | |
| 289 | entry++; |
| 290 | } |
| 291 | |
| 292 | /* |
| 293 | * Create all numbered nodes |
| 294 | */ |
| 295 | for(var_num = 0; var_num <= 255; var_num++) { |
| 296 | entry = &srm_numbered_entries[var_num]; |
| 297 | entry->name = number[var_num]; |
| 298 | |
| 299 | entry->proc_entry = create_proc_entry(entry->name, |
| 300 | 0644, numbered_dir); |
| 301 | if(entry->proc_entry == NULL) |
| 302 | goto cleanup; |
| 303 | |
| 304 | entry->id = var_num; |
| 305 | entry->proc_entry->data = (void *) entry; |
| 306 | entry->proc_entry->owner = THIS_MODULE; |
| 307 | entry->proc_entry->read_proc = srm_env_read; |
| 308 | entry->proc_entry->write_proc = srm_env_write; |
| 309 | } |
| 310 | |
| 311 | printk(KERN_INFO "%s: version %s loaded successfully\n", NAME, |
| 312 | VERSION); |
| 313 | |
| 314 | return 0; |
| 315 | |
| 316 | cleanup: |
| 317 | srm_env_cleanup(); |
| 318 | |
| 319 | return -ENOMEM; |
| 320 | } |
| 321 | |
| 322 | |
| 323 | static void __exit |
| 324 | srm_env_exit(void) |
| 325 | { |
| 326 | srm_env_cleanup(); |
| 327 | printk(KERN_INFO "%s: unloaded successfully\n", NAME); |
| 328 | |
| 329 | return; |
| 330 | } |
| 331 | |
| 332 | |
| 333 | module_init(srm_env_init); |
| 334 | module_exit(srm_env_exit); |
| 335 | |