|  | /* | 
|  | *  linux/fs/stat.c | 
|  | * | 
|  | *  Copyright (C) 1991, 1992  Linus Torvalds | 
|  | */ | 
|  |  | 
|  | #include <linux/module.h> | 
|  | #include <linux/mm.h> | 
|  | #include <linux/errno.h> | 
|  | #include <linux/file.h> | 
|  | #include <linux/smp_lock.h> | 
|  | #include <linux/highuid.h> | 
|  | #include <linux/fs.h> | 
|  | #include <linux/namei.h> | 
|  | #include <linux/security.h> | 
|  | #include <linux/syscalls.h> | 
|  | #include <linux/pagemap.h> | 
|  |  | 
|  | #include <asm/uaccess.h> | 
|  | #include <asm/unistd.h> | 
|  |  | 
|  | void generic_fillattr(struct inode *inode, struct kstat *stat) | 
|  | { | 
|  | stat->dev = inode->i_sb->s_dev; | 
|  | stat->ino = inode->i_ino; | 
|  | stat->mode = inode->i_mode; | 
|  | stat->nlink = inode->i_nlink; | 
|  | stat->uid = inode->i_uid; | 
|  | stat->gid = inode->i_gid; | 
|  | stat->rdev = inode->i_rdev; | 
|  | stat->atime = inode->i_atime; | 
|  | stat->mtime = inode->i_mtime; | 
|  | stat->ctime = inode->i_ctime; | 
|  | stat->size = i_size_read(inode); | 
|  | stat->blocks = inode->i_blocks; | 
|  | stat->blksize = (1 << inode->i_blkbits); | 
|  | } | 
|  |  | 
|  | EXPORT_SYMBOL(generic_fillattr); | 
|  |  | 
|  | int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) | 
|  | { | 
|  | struct inode *inode = dentry->d_inode; | 
|  | int retval; | 
|  |  | 
|  | retval = security_inode_getattr(mnt, dentry); | 
|  | if (retval) | 
|  | return retval; | 
|  |  | 
|  | if (inode->i_op->getattr) | 
|  | return inode->i_op->getattr(mnt, dentry, stat); | 
|  |  | 
|  | generic_fillattr(inode, stat); | 
|  | if (!stat->blksize) { | 
|  | struct super_block *s = inode->i_sb; | 
|  | unsigned blocks; | 
|  | blocks = (stat->size+s->s_blocksize-1) >> s->s_blocksize_bits; | 
|  | stat->blocks = (s->s_blocksize / 512) * blocks; | 
|  | stat->blksize = s->s_blocksize; | 
|  | } | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | EXPORT_SYMBOL(vfs_getattr); | 
|  |  | 
|  | int vfs_stat_fd(int dfd, char __user *name, struct kstat *stat) | 
|  | { | 
|  | struct nameidata nd; | 
|  | int error; | 
|  |  | 
|  | error = __user_walk_fd(dfd, name, LOOKUP_FOLLOW, &nd); | 
|  | if (!error) { | 
|  | error = vfs_getattr(nd.mnt, nd.dentry, stat); | 
|  | path_release(&nd); | 
|  | } | 
|  | return error; | 
|  | } | 
|  |  | 
|  | int vfs_stat(char __user *name, struct kstat *stat) | 
|  | { | 
|  | return vfs_stat_fd(AT_FDCWD, name, stat); | 
|  | } | 
|  |  | 
|  | EXPORT_SYMBOL(vfs_stat); | 
|  |  | 
|  | int vfs_lstat_fd(int dfd, char __user *name, struct kstat *stat) | 
|  | { | 
|  | struct nameidata nd; | 
|  | int error; | 
|  |  | 
|  | error = __user_walk_fd(dfd, name, 0, &nd); | 
|  | if (!error) { | 
|  | error = vfs_getattr(nd.mnt, nd.dentry, stat); | 
|  | path_release(&nd); | 
|  | } | 
|  | return error; | 
|  | } | 
|  |  | 
|  | int vfs_lstat(char __user *name, struct kstat *stat) | 
|  | { | 
|  | return vfs_lstat_fd(AT_FDCWD, name, stat); | 
|  | } | 
|  |  | 
|  | EXPORT_SYMBOL(vfs_lstat); | 
|  |  | 
|  | int vfs_fstat(unsigned int fd, struct kstat *stat) | 
|  | { | 
|  | struct file *f = fget(fd); | 
|  | int error = -EBADF; | 
|  |  | 
|  | if (f) { | 
|  | error = vfs_getattr(f->f_vfsmnt, f->f_dentry, stat); | 
|  | fput(f); | 
|  | } | 
|  | return error; | 
|  | } | 
|  |  | 
|  | EXPORT_SYMBOL(vfs_fstat); | 
|  |  | 
|  | #ifdef __ARCH_WANT_OLD_STAT | 
|  |  | 
|  | /* | 
|  | * For backward compatibility?  Maybe this should be moved | 
|  | * into arch/i386 instead? | 
|  | */ | 
|  | static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) | 
|  | { | 
|  | static int warncount = 5; | 
|  | struct __old_kernel_stat tmp; | 
|  |  | 
|  | if (warncount > 0) { | 
|  | warncount--; | 
|  | printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", | 
|  | current->comm); | 
|  | } else if (warncount < 0) { | 
|  | /* it's laughable, but... */ | 
|  | warncount = 0; | 
|  | } | 
|  |  | 
|  | memset(&tmp, 0, sizeof(struct __old_kernel_stat)); | 
|  | tmp.st_dev = old_encode_dev(stat->dev); | 
|  | tmp.st_ino = stat->ino; | 
|  | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) | 
|  | return -EOVERFLOW; | 
|  | tmp.st_mode = stat->mode; | 
|  | tmp.st_nlink = stat->nlink; | 
|  | if (tmp.st_nlink != stat->nlink) | 
|  | return -EOVERFLOW; | 
|  | SET_UID(tmp.st_uid, stat->uid); | 
|  | SET_GID(tmp.st_gid, stat->gid); | 
|  | tmp.st_rdev = old_encode_dev(stat->rdev); | 
|  | #if BITS_PER_LONG == 32 | 
|  | if (stat->size > MAX_NON_LFS) | 
|  | return -EOVERFLOW; | 
|  | #endif | 
|  | tmp.st_size = stat->size; | 
|  | tmp.st_atime = stat->atime.tv_sec; | 
|  | tmp.st_mtime = stat->mtime.tv_sec; | 
|  | tmp.st_ctime = stat->ctime.tv_sec; | 
|  | return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; | 
|  | } | 
|  |  | 
|  | asmlinkage long sys_stat(char __user * filename, struct __old_kernel_stat __user * statbuf) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = vfs_stat_fd(AT_FDCWD, filename, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_old_stat(&stat, statbuf); | 
|  |  | 
|  | return error; | 
|  | } | 
|  | asmlinkage long sys_lstat(char __user * filename, struct __old_kernel_stat __user * statbuf) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_old_stat(&stat, statbuf); | 
|  |  | 
|  | return error; | 
|  | } | 
|  | asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat __user * statbuf) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = vfs_fstat(fd, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_old_stat(&stat, statbuf); | 
|  |  | 
|  | return error; | 
|  | } | 
|  |  | 
|  | #endif /* __ARCH_WANT_OLD_STAT */ | 
|  |  | 
|  | static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) | 
|  | { | 
|  | struct stat tmp; | 
|  |  | 
|  | #if BITS_PER_LONG == 32 | 
|  | if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev)) | 
|  | return -EOVERFLOW; | 
|  | #else | 
|  | if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) | 
|  | return -EOVERFLOW; | 
|  | #endif | 
|  |  | 
|  | memset(&tmp, 0, sizeof(tmp)); | 
|  | #if BITS_PER_LONG == 32 | 
|  | tmp.st_dev = old_encode_dev(stat->dev); | 
|  | #else | 
|  | tmp.st_dev = new_encode_dev(stat->dev); | 
|  | #endif | 
|  | tmp.st_ino = stat->ino; | 
|  | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) | 
|  | return -EOVERFLOW; | 
|  | tmp.st_mode = stat->mode; | 
|  | tmp.st_nlink = stat->nlink; | 
|  | if (tmp.st_nlink != stat->nlink) | 
|  | return -EOVERFLOW; | 
|  | SET_UID(tmp.st_uid, stat->uid); | 
|  | SET_GID(tmp.st_gid, stat->gid); | 
|  | #if BITS_PER_LONG == 32 | 
|  | tmp.st_rdev = old_encode_dev(stat->rdev); | 
|  | #else | 
|  | tmp.st_rdev = new_encode_dev(stat->rdev); | 
|  | #endif | 
|  | #if BITS_PER_LONG == 32 | 
|  | if (stat->size > MAX_NON_LFS) | 
|  | return -EOVERFLOW; | 
|  | #endif | 
|  | tmp.st_size = stat->size; | 
|  | tmp.st_atime = stat->atime.tv_sec; | 
|  | tmp.st_mtime = stat->mtime.tv_sec; | 
|  | tmp.st_ctime = stat->ctime.tv_sec; | 
|  | #ifdef STAT_HAVE_NSEC | 
|  | tmp.st_atime_nsec = stat->atime.tv_nsec; | 
|  | tmp.st_mtime_nsec = stat->mtime.tv_nsec; | 
|  | tmp.st_ctime_nsec = stat->ctime.tv_nsec; | 
|  | #endif | 
|  | tmp.st_blocks = stat->blocks; | 
|  | tmp.st_blksize = stat->blksize; | 
|  | return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; | 
|  | } | 
|  |  | 
|  | asmlinkage long sys_newstat(char __user *filename, struct stat __user *statbuf) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = vfs_stat_fd(AT_FDCWD, filename, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_new_stat(&stat, statbuf); | 
|  |  | 
|  | return error; | 
|  | } | 
|  |  | 
|  | asmlinkage long sys_newlstat(char __user *filename, struct stat __user *statbuf) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_new_stat(&stat, statbuf); | 
|  |  | 
|  | return error; | 
|  | } | 
|  |  | 
|  | #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) | 
|  | asmlinkage long sys_newfstatat(int dfd, char __user *filename, | 
|  | struct stat __user *statbuf, int flag) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = -EINVAL; | 
|  |  | 
|  | if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) | 
|  | goto out; | 
|  |  | 
|  | if (flag & AT_SYMLINK_NOFOLLOW) | 
|  | error = vfs_lstat_fd(dfd, filename, &stat); | 
|  | else | 
|  | error = vfs_stat_fd(dfd, filename, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_new_stat(&stat, statbuf); | 
|  |  | 
|  | out: | 
|  | return error; | 
|  | } | 
|  | #endif | 
|  |  | 
|  | asmlinkage long sys_newfstat(unsigned int fd, struct stat __user *statbuf) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = vfs_fstat(fd, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_new_stat(&stat, statbuf); | 
|  |  | 
|  | return error; | 
|  | } | 
|  |  | 
|  | asmlinkage long sys_readlinkat(int dfd, const char __user *path, | 
|  | char __user *buf, int bufsiz) | 
|  | { | 
|  | struct nameidata nd; | 
|  | int error; | 
|  |  | 
|  | if (bufsiz <= 0) | 
|  | return -EINVAL; | 
|  |  | 
|  | error = __user_walk_fd(dfd, path, 0, &nd); | 
|  | if (!error) { | 
|  | struct inode * inode = nd.dentry->d_inode; | 
|  |  | 
|  | error = -EINVAL; | 
|  | if (inode->i_op && inode->i_op->readlink) { | 
|  | error = security_inode_readlink(nd.dentry); | 
|  | if (!error) { | 
|  | touch_atime(nd.mnt, nd.dentry); | 
|  | error = inode->i_op->readlink(nd.dentry, buf, bufsiz); | 
|  | } | 
|  | } | 
|  | path_release(&nd); | 
|  | } | 
|  | return error; | 
|  | } | 
|  |  | 
|  | asmlinkage long sys_readlink(const char __user *path, char __user *buf, | 
|  | int bufsiz) | 
|  | { | 
|  | return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); | 
|  | } | 
|  |  | 
|  |  | 
|  | /* ---------- LFS-64 ----------- */ | 
|  | #ifdef __ARCH_WANT_STAT64 | 
|  |  | 
|  | static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) | 
|  | { | 
|  | struct stat64 tmp; | 
|  |  | 
|  | memset(&tmp, 0, sizeof(struct stat64)); | 
|  | #ifdef CONFIG_MIPS | 
|  | /* mips has weird padding, so we don't get 64 bits there */ | 
|  | if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) | 
|  | return -EOVERFLOW; | 
|  | tmp.st_dev = new_encode_dev(stat->dev); | 
|  | tmp.st_rdev = new_encode_dev(stat->rdev); | 
|  | #else | 
|  | tmp.st_dev = huge_encode_dev(stat->dev); | 
|  | tmp.st_rdev = huge_encode_dev(stat->rdev); | 
|  | #endif | 
|  | tmp.st_ino = stat->ino; | 
|  | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) | 
|  | return -EOVERFLOW; | 
|  | #ifdef STAT64_HAS_BROKEN_ST_INO | 
|  | tmp.__st_ino = stat->ino; | 
|  | #endif | 
|  | tmp.st_mode = stat->mode; | 
|  | tmp.st_nlink = stat->nlink; | 
|  | tmp.st_uid = stat->uid; | 
|  | tmp.st_gid = stat->gid; | 
|  | tmp.st_atime = stat->atime.tv_sec; | 
|  | tmp.st_atime_nsec = stat->atime.tv_nsec; | 
|  | tmp.st_mtime = stat->mtime.tv_sec; | 
|  | tmp.st_mtime_nsec = stat->mtime.tv_nsec; | 
|  | tmp.st_ctime = stat->ctime.tv_sec; | 
|  | tmp.st_ctime_nsec = stat->ctime.tv_nsec; | 
|  | tmp.st_size = stat->size; | 
|  | tmp.st_blocks = stat->blocks; | 
|  | tmp.st_blksize = stat->blksize; | 
|  | return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; | 
|  | } | 
|  |  | 
|  | asmlinkage long sys_stat64(char __user * filename, struct stat64 __user * statbuf) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = vfs_stat(filename, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_new_stat64(&stat, statbuf); | 
|  |  | 
|  | return error; | 
|  | } | 
|  | asmlinkage long sys_lstat64(char __user * filename, struct stat64 __user * statbuf) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = vfs_lstat(filename, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_new_stat64(&stat, statbuf); | 
|  |  | 
|  | return error; | 
|  | } | 
|  | asmlinkage long sys_fstat64(unsigned long fd, struct stat64 __user * statbuf) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = vfs_fstat(fd, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_new_stat64(&stat, statbuf); | 
|  |  | 
|  | return error; | 
|  | } | 
|  |  | 
|  | asmlinkage long sys_fstatat64(int dfd, char __user *filename, | 
|  | struct stat64 __user *statbuf, int flag) | 
|  | { | 
|  | struct kstat stat; | 
|  | int error = -EINVAL; | 
|  |  | 
|  | if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) | 
|  | goto out; | 
|  |  | 
|  | if (flag & AT_SYMLINK_NOFOLLOW) | 
|  | error = vfs_lstat_fd(dfd, filename, &stat); | 
|  | else | 
|  | error = vfs_stat_fd(dfd, filename, &stat); | 
|  |  | 
|  | if (!error) | 
|  | error = cp_new_stat64(&stat, statbuf); | 
|  |  | 
|  | out: | 
|  | return error; | 
|  | } | 
|  | #endif /* __ARCH_WANT_STAT64 */ | 
|  |  | 
|  | void inode_add_bytes(struct inode *inode, loff_t bytes) | 
|  | { | 
|  | spin_lock(&inode->i_lock); | 
|  | inode->i_blocks += bytes >> 9; | 
|  | bytes &= 511; | 
|  | inode->i_bytes += bytes; | 
|  | if (inode->i_bytes >= 512) { | 
|  | inode->i_blocks++; | 
|  | inode->i_bytes -= 512; | 
|  | } | 
|  | spin_unlock(&inode->i_lock); | 
|  | } | 
|  |  | 
|  | EXPORT_SYMBOL(inode_add_bytes); | 
|  |  | 
|  | void inode_sub_bytes(struct inode *inode, loff_t bytes) | 
|  | { | 
|  | spin_lock(&inode->i_lock); | 
|  | inode->i_blocks -= bytes >> 9; | 
|  | bytes &= 511; | 
|  | if (inode->i_bytes < bytes) { | 
|  | inode->i_blocks--; | 
|  | inode->i_bytes += 512; | 
|  | } | 
|  | inode->i_bytes -= bytes; | 
|  | spin_unlock(&inode->i_lock); | 
|  | } | 
|  |  | 
|  | EXPORT_SYMBOL(inode_sub_bytes); | 
|  |  | 
|  | loff_t inode_get_bytes(struct inode *inode) | 
|  | { | 
|  | loff_t ret; | 
|  |  | 
|  | spin_lock(&inode->i_lock); | 
|  | ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; | 
|  | spin_unlock(&inode->i_lock); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | EXPORT_SYMBOL(inode_get_bytes); | 
|  |  | 
|  | void inode_set_bytes(struct inode *inode, loff_t bytes) | 
|  | { | 
|  | /* Caller is here responsible for sufficient locking | 
|  | * (ie. inode->i_lock) */ | 
|  | inode->i_blocks = bytes >> 9; | 
|  | inode->i_bytes = bytes & 511; | 
|  | } | 
|  |  | 
|  | EXPORT_SYMBOL(inode_set_bytes); |