1/* 2 * linux/fs/stat.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7#include <linux/config.h> 8#include <linux/mm.h> 9#include <linux/errno.h> 10#include <linux/file.h> 11#include <linux/smp_lock.h> 12#include <linux/highuid.h> 13 14#include <asm/uaccess.h> 15 16/* 17 * Revalidate the inode. This is required for proper NFS attribute caching. 18 */ 19static __inline__ int 20do_revalidate(struct dentry *dentry) 21{ 22 struct inode * inode = dentry->d_inode; 23 if (inode->i_op && inode->i_op->revalidate) 24 return inode->i_op->revalidate(dentry); 25 return 0; 26} 27 28 29#if defined(__i386__) || defined(__m68k__) || defined(__ppc__) || defined(__sh__) 30 31/* 32 * For backward compatibility? Maybe this should be moved 33 * into arch/i386 instead? 34 */ 35static int cp_old_stat(struct inode * inode, struct __old_kernel_stat * statbuf) 36{ 37 static int warncount = 5; 38 struct __old_kernel_stat tmp; 39 40 if (warncount > 0) { 41 warncount--; 42 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", 43 current->comm); 44 } else if (warncount < 0) { 45 /* it's laughable, but... */ 46 warncount = 0; 47 } 48 49 tmp.st_dev = kdev_t_to_nr(inode->i_dev); 50 tmp.st_ino = inode->i_ino; 51 tmp.st_mode = inode->i_mode; 52 tmp.st_nlink = inode->i_nlink; 53 SET_OLDSTAT_UID(tmp, inode->i_uid); 54 SET_OLDSTAT_GID(tmp, inode->i_gid); 55 tmp.st_rdev = kdev_t_to_nr(inode->i_rdev); 56#if BITS_PER_LONG == 32 57 if (inode->i_size > MAX_NON_LFS) 58 return -EOVERFLOW; 59#endif 60 tmp.st_size = inode->i_size; 61 tmp.st_atime = inode->i_atime; 62 tmp.st_mtime = inode->i_mtime; 63 tmp.st_ctime = inode->i_ctime; 64 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 65} 66 67#endif 68 69static int cp_new_stat(struct inode * inode, struct stat * statbuf) 70{ 71 struct stat tmp; 72 unsigned int blocks, indirect; 73 74 memset(&tmp, 0, sizeof(tmp)); 75 tmp.st_dev = kdev_t_to_nr(inode->i_dev); 76 tmp.st_ino = inode->i_ino; 77 tmp.st_mode = inode->i_mode; 78 tmp.st_nlink = inode->i_nlink; 79 SET_STAT_UID(tmp, inode->i_uid); 80 SET_STAT_GID(tmp, inode->i_gid); 81 tmp.st_rdev = kdev_t_to_nr(inode->i_rdev); 82#if BITS_PER_LONG == 32 83 if (inode->i_size > MAX_NON_LFS) 84 return -EOVERFLOW; 85#endif 86 tmp.st_size = inode->i_size; 87 tmp.st_atime = inode->i_atime; 88 tmp.st_mtime = inode->i_mtime; 89 tmp.st_ctime = inode->i_ctime; 90/* 91 * st_blocks and st_blksize are approximated with a simple algorithm if 92 * they aren't supported directly by the filesystem. The minix and msdos 93 * filesystems don't keep track of blocks, so they would either have to 94 * be counted explicitly (by delving into the file itself), or by using 95 * this simple algorithm to get a reasonable (although not 100% accurate) 96 * value. 97 */ 98 99/* 100 * Use minix fs values for the number of direct and indirect blocks. The 101 * count is now exact for the minix fs except that it counts zero blocks. 102 * Everything is in units of BLOCK_SIZE until the assignment to 103 * tmp.st_blksize. 104 */ 105#define D_B 7 106#define I_B (BLOCK_SIZE / sizeof(unsigned short)) 107 108 if (!inode->i_blksize) { 109 blocks = (tmp.st_size + BLOCK_SIZE - 1) / BLOCK_SIZE; 110 if (blocks > D_B) { 111 indirect = (blocks - D_B + I_B - 1) / I_B; 112 blocks += indirect; 113 if (indirect > 1) { 114 indirect = (indirect - 1 + I_B - 1) / I_B; 115 blocks += indirect; 116 if (indirect > 1) 117 blocks++; 118 } 119 } 120 tmp.st_blocks = (BLOCK_SIZE / 512) * blocks; 121 tmp.st_blksize = BLOCK_SIZE; 122 } else { 123 tmp.st_blocks = inode->i_blocks; 124 tmp.st_blksize = inode->i_blksize; 125 } 126 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 127} 128 129 130#if defined(__i386__) || defined(__m68k__) || defined(__ppc__) || defined(__sh__) 131/* 132 * For backward compatibility? Maybe this should be moved 133 * into arch/i386 instead? 134 */ 135asmlinkage long sys_stat(char * filename, struct __old_kernel_stat * statbuf) 136{ 137 struct nameidata nd; 138 int error; 139 140 error = user_path_walk(filename, &nd); 141 if (!error) { 142 error = do_revalidate(nd.dentry); 143 if (!error) 144 error = cp_old_stat(nd.dentry->d_inode, statbuf); 145 path_release(&nd); 146 } 147 return error; 148} 149#endif 150 151asmlinkage long sys_newstat(char * filename, struct stat * statbuf) 152{ 153 struct nameidata nd; 154 int error; 155 156 error = user_path_walk(filename, &nd); 157 if (!error) { 158 error = do_revalidate(nd.dentry); 159 if (!error) 160 error = cp_new_stat(nd.dentry->d_inode, statbuf); 161 path_release(&nd); 162 } 163 return error; 164} 165 166#if defined(__i386__) || defined(__m68k__) || defined(__ppc__) || defined(__sh__) 167 168/* 169 * For backward compatibility? Maybe this should be moved 170 * into arch/i386 instead? 171 */ 172asmlinkage long sys_lstat(char * filename, struct __old_kernel_stat * statbuf) 173{ 174 struct nameidata nd; 175 int error; 176 177 error = user_path_walk_link(filename, &nd); 178 if (!error) { 179 error = do_revalidate(nd.dentry); 180 if (!error) 181 error = cp_old_stat(nd.dentry->d_inode, statbuf); 182 path_release(&nd); 183 } 184 return error; 185} 186 187#endif 188 189asmlinkage long sys_newlstat(char * filename, struct stat * statbuf) 190{ 191 struct nameidata nd; 192 int error; 193 194 error = user_path_walk_link(filename, &nd); 195 if (!error) { 196 error = do_revalidate(nd.dentry); 197 if (!error) 198 error = cp_new_stat(nd.dentry->d_inode, statbuf); 199 path_release(&nd); 200 } 201 return error; 202} 203 204#if defined(__i386__) || defined(__m68k__) || defined(__ppc__) || defined(__sh__) 205 206/* 207 * For backward compatibility? Maybe this should be moved 208 * into arch/i386 instead? 209 */ 210asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat * statbuf) 211{ 212 struct file * f; 213 int err = -EBADF; 214 215 f = fget(fd); 216 if (f) { 217 struct dentry * dentry = f->f_dentry; 218 219 err = do_revalidate(dentry); 220 if (!err) 221 err = cp_old_stat(dentry->d_inode, statbuf); 222 fput(f); 223 } 224 return err; 225} 226 227#endif 228 229asmlinkage long sys_newfstat(unsigned int fd, struct stat * statbuf) 230{ 231 struct file * f; 232 int err = -EBADF; 233 234 f = fget(fd); 235 if (f) { 236 struct dentry * dentry = f->f_dentry; 237 238 err = do_revalidate(dentry); 239 if (!err) 240 err = cp_new_stat(dentry->d_inode, statbuf); 241 fput(f); 242 } 243 return err; 244} 245 246asmlinkage long sys_readlink(const char * path, char * buf, int bufsiz) 247{ 248 struct nameidata nd; 249 int error; 250 251 if (bufsiz <= 0) 252 return -EINVAL; 253 254 error = user_path_walk_link(path, &nd); 255 if (!error) { 256 struct inode * inode = nd.dentry->d_inode; 257 258 error = -EINVAL; 259 if (inode->i_op && inode->i_op->readlink && 260 !(error = do_revalidate(nd.dentry))) { 261 UPDATE_ATIME(inode); 262 error = inode->i_op->readlink(nd.dentry, buf, bufsiz); 263 } 264 path_release(&nd); 265 } 266 return error; 267} 268 269 270/* ---------- LFS-64 ----------- */ 271#if !defined(__alpha__) && !defined(__ia64__) && !defined(__mips64) && !defined(__x86_64__) && !defined(CONFIG_ARCH_S390X) 272 273static long cp_new_stat64(struct inode * inode, struct stat64 * statbuf) 274{ 275 struct stat64 tmp; 276 unsigned int blocks, indirect; 277 278 memset(&tmp, 0, sizeof(tmp)); 279 tmp.st_dev = kdev_t_to_nr(inode->i_dev); 280 tmp.st_ino = inode->i_ino; 281#ifdef STAT64_HAS_BROKEN_ST_INO 282 tmp.__st_ino = inode->i_ino; 283#endif 284 tmp.st_mode = inode->i_mode; 285 tmp.st_nlink = inode->i_nlink; 286 tmp.st_uid = inode->i_uid; 287 tmp.st_gid = inode->i_gid; 288 tmp.st_rdev = kdev_t_to_nr(inode->i_rdev); 289 tmp.st_atime = inode->i_atime; 290 tmp.st_mtime = inode->i_mtime; 291 tmp.st_ctime = inode->i_ctime; 292 tmp.st_size = inode->i_size; 293/* 294 * st_blocks and st_blksize are approximated with a simple algorithm if 295 * they aren't supported directly by the filesystem. The minix and msdos 296 * filesystems don't keep track of blocks, so they would either have to 297 * be counted explicitly (by delving into the file itself), or by using 298 * this simple algorithm to get a reasonable (although not 100% accurate) 299 * value. 300 */ 301 302/* 303 * Use minix fs values for the number of direct and indirect blocks. The 304 * count is now exact for the minix fs except that it counts zero blocks. 305 * Everything is in units of BLOCK_SIZE until the assignment to 306 * tmp.st_blksize. 307 */ 308#define D_B 7 309#define I_B (BLOCK_SIZE / sizeof(unsigned short)) 310 311 if (!inode->i_blksize) { 312 blocks = (tmp.st_size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; 313 if (blocks > D_B) { 314 indirect = (blocks - D_B + I_B - 1) / I_B; 315 blocks += indirect; 316 if (indirect > 1) { 317 indirect = (indirect - 1 + I_B - 1) / I_B; 318 blocks += indirect; 319 if (indirect > 1) 320 blocks++; 321 } 322 } 323 tmp.st_blocks = (BLOCK_SIZE / 512) * blocks; 324 tmp.st_blksize = BLOCK_SIZE; 325 } else { 326 tmp.st_blocks = inode->i_blocks; 327 tmp.st_blksize = inode->i_blksize; 328 } 329 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 330} 331 332asmlinkage long sys_stat64(char * filename, struct stat64 * statbuf, long flags) 333{ 334 struct nameidata nd; 335 int error; 336 337 error = user_path_walk(filename, &nd); 338 if (!error) { 339 error = do_revalidate(nd.dentry); 340 if (!error) 341 error = cp_new_stat64(nd.dentry->d_inode, statbuf); 342 path_release(&nd); 343 } 344 return error; 345} 346 347asmlinkage long sys_lstat64(char * filename, struct stat64 * statbuf, long flags) 348{ 349 struct nameidata nd; 350 int error; 351 352 error = user_path_walk_link(filename, &nd); 353 if (!error) { 354 error = do_revalidate(nd.dentry); 355 if (!error) 356 error = cp_new_stat64(nd.dentry->d_inode, statbuf); 357 path_release(&nd); 358 } 359 return error; 360} 361 362asmlinkage long sys_fstat64(unsigned long fd, struct stat64 * statbuf, long flags) 363{ 364 struct file * f; 365 int err = -EBADF; 366 367 f = fget(fd); 368 if (f) { 369 struct dentry * dentry = f->f_dentry; 370 371 err = do_revalidate(dentry); 372 if (!err) 373 err = cp_new_stat64(dentry->d_inode, statbuf); 374 fput(f); 375 } 376 return err; 377} 378 379#endif /* LFS-64 */ 380