1/* 2 * srm_env.c - Access to SRM environment 3 * variables through linux' procfs 4 * 5 * (C) 2001,2002,2006 by 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#include <linux/kernel.h> 33#include <linux/gfp.h> 34#include <linux/module.h> 35#include <linux/init.h> 36#include <linux/proc_fs.h> 37#include <linux/seq_file.h> 38#include <asm/console.h> 39#include <asm/uaccess.h> 40#include <asm/machvec.h> 41 42#define BASE_DIR "srm_environment" /* Subdir in /proc/ */ 43#define NAMED_DIR "named_variables" /* Subdir for known variables */ 44#define NUMBERED_DIR "numbered_variables" /* Subdir for all variables */ 45#define VERSION "0.0.6" /* Module version */ 46#define NAME "srm_env" /* Module name */ 47 48MODULE_AUTHOR("Jan-Benedict Glaw <jbglaw@lug-owl.de>"); 49MODULE_DESCRIPTION("Accessing Alpha SRM environment through procfs interface"); 50MODULE_LICENSE("GPL"); 51 52typedef struct _srm_env { 53 char *name; 54 unsigned long id; 55 struct proc_dir_entry *proc_entry; 56} srm_env_t; 57 58static struct proc_dir_entry *base_dir; 59static struct proc_dir_entry *named_dir; 60static struct proc_dir_entry *numbered_dir; 61static char number[256][4]; 62 63static srm_env_t srm_named_entries[] = { 64 { "auto_action", ENV_AUTO_ACTION }, 65 { "boot_dev", ENV_BOOT_DEV }, 66 { "bootdef_dev", ENV_BOOTDEF_DEV }, 67 { "booted_dev", ENV_BOOTED_DEV }, 68 { "boot_file", ENV_BOOT_FILE }, 69 { "booted_file", ENV_BOOTED_FILE }, 70 { "boot_osflags", ENV_BOOT_OSFLAGS }, 71 { "booted_osflags", ENV_BOOTED_OSFLAGS }, 72 { "boot_reset", ENV_BOOT_RESET }, 73 { "dump_dev", ENV_DUMP_DEV }, 74 { "enable_audit", ENV_ENABLE_AUDIT }, 75 { "license", ENV_LICENSE }, 76 { "char_set", ENV_CHAR_SET }, 77 { "language", ENV_LANGUAGE }, 78 { "tty_dev", ENV_TTY_DEV }, 79 { NULL, 0 }, 80}; 81static srm_env_t srm_numbered_entries[256]; 82 83 84static int srm_env_proc_show(struct seq_file *m, void *v) 85{ 86 unsigned long ret; 87 srm_env_t *entry; 88 char *page; 89 90 entry = m->private; 91 page = (char *)__get_free_page(GFP_USER); 92 if (!page) 93 return -ENOMEM; 94 95 ret = callback_getenv(entry->id, page, PAGE_SIZE); 96 97 if ((ret >> 61) == 0) { 98 seq_write(m, page, ret); 99 ret = 0; 100 } else 101 ret = -EFAULT; 102 free_page((unsigned long)page); 103 return ret; 104} 105 106static int srm_env_proc_open(struct inode *inode, struct file *file) 107{ 108 return single_open(file, srm_env_proc_show, PDE(inode)->data); 109} 110 111static ssize_t srm_env_proc_write(struct file *file, const char __user *buffer, 112 size_t count, loff_t *pos) 113{ 114 int res; 115 srm_env_t *entry = PDE(file->f_path.dentry->d_inode)->data; 116 char *buf = (char *) __get_free_page(GFP_USER); 117 unsigned long ret1, ret2; 118 119 if (!buf) 120 return -ENOMEM; 121 122 res = -EINVAL; 123 if (count >= PAGE_SIZE) 124 goto out; 125 126 res = -EFAULT; 127 if (copy_from_user(buf, buffer, count)) 128 goto out; 129 buf[count] = '\0'; 130 131 ret1 = callback_setenv(entry->id, buf, count); 132 if ((ret1 >> 61) == 0) { 133 do 134 ret2 = callback_save_env(); 135 while((ret2 >> 61) == 1); 136 res = (int) ret1; 137 } 138 139 out: 140 free_page((unsigned long)buf); 141 return res; 142} 143 144static const struct file_operations srm_env_proc_fops = { 145 .owner = THIS_MODULE, 146 .open = srm_env_proc_open, 147 .read = seq_read, 148 .llseek = seq_lseek, 149 .release = single_release, 150 .write = srm_env_proc_write, 151}; 152 153static void 154srm_env_cleanup(void) 155{ 156 srm_env_t *entry; 157 unsigned long var_num; 158 159 if (base_dir) { 160 /* 161 * Remove named entries 162 */ 163 if (named_dir) { 164 entry = srm_named_entries; 165 while (entry->name != NULL && entry->id != 0) { 166 if (entry->proc_entry) { 167 remove_proc_entry(entry->name, 168 named_dir); 169 entry->proc_entry = NULL; 170 } 171 entry++; 172 } 173 remove_proc_entry(NAMED_DIR, base_dir); 174 } 175 176 /* 177 * Remove numbered entries 178 */ 179 if (numbered_dir) { 180 for (var_num = 0; var_num <= 255; var_num++) { 181 entry = &srm_numbered_entries[var_num]; 182 183 if (entry->proc_entry) { 184 remove_proc_entry(entry->name, 185 numbered_dir); 186 entry->proc_entry = NULL; 187 entry->name = NULL; 188 } 189 } 190 remove_proc_entry(NUMBERED_DIR, base_dir); 191 } 192 193 remove_proc_entry(BASE_DIR, NULL); 194 } 195 196 return; 197} 198 199static int __init 200srm_env_init(void) 201{ 202 srm_env_t *entry; 203 unsigned long var_num; 204 205 /* 206 * Check system 207 */ 208 if (!alpha_using_srm) { 209 printk(KERN_INFO "%s: This Alpha system doesn't " 210 "know about SRM (or you've booted " 211 "SRM->MILO->Linux, which gets " 212 "misdetected)...\n", __func__); 213 return -ENODEV; 214 } 215 216 /* 217 * Init numbers 218 */ 219 for (var_num = 0; var_num <= 255; var_num++) 220 sprintf(number[var_num], "%ld", var_num); 221 222 /* 223 * Create base directory 224 */ 225 base_dir = proc_mkdir(BASE_DIR, NULL); 226 if (!base_dir) { 227 printk(KERN_ERR "Couldn't create base dir /proc/%s\n", 228 BASE_DIR); 229 goto cleanup; 230 } 231 232 /* 233 * Create per-name subdirectory 234 */ 235 named_dir = proc_mkdir(NAMED_DIR, base_dir); 236 if (!named_dir) { 237 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n", 238 BASE_DIR, NAMED_DIR); 239 goto cleanup; 240 } 241 242 /* 243 * Create per-number subdirectory 244 */ 245 numbered_dir = proc_mkdir(NUMBERED_DIR, base_dir); 246 if (!numbered_dir) { 247 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n", 248 BASE_DIR, NUMBERED_DIR); 249 goto cleanup; 250 251 } 252 253 /* 254 * Create all named nodes 255 */ 256 entry = srm_named_entries; 257 while (entry->name && entry->id) { 258 entry->proc_entry = proc_create_data(entry->name, 0644, named_dir, 259 &srm_env_proc_fops, entry); 260 if (!entry->proc_entry) 261 goto cleanup; 262 entry++; 263 } 264 265 /* 266 * Create all numbered nodes 267 */ 268 for (var_num = 0; var_num <= 255; var_num++) { 269 entry = &srm_numbered_entries[var_num]; 270 entry->name = number[var_num]; 271 272 entry->proc_entry = proc_create_data(entry->name, 0644, numbered_dir, 273 &srm_env_proc_fops, entry); 274 if (!entry->proc_entry) 275 goto cleanup; 276 277 entry->id = var_num; 278 } 279 280 printk(KERN_INFO "%s: version %s loaded successfully\n", NAME, 281 VERSION); 282 283 return 0; 284 285cleanup: 286 srm_env_cleanup(); 287 288 return -ENOMEM; 289} 290 291static void __exit 292srm_env_exit(void) 293{ 294 srm_env_cleanup(); 295 printk(KERN_INFO "%s: unloaded successfully\n", NAME); 296 297 return; 298} 299 300module_init(srm_env_init); 301module_exit(srm_env_exit); 302