diff options
Diffstat (limited to 'fs/stat.c')
| -rw-r--r-- | fs/stat.c | 511 |
1 files changed, 511 insertions, 0 deletions
diff --git a/fs/stat.c b/fs/stat.c new file mode 100644 index 000000000..cccc1aab9 --- /dev/null +++ b/fs/stat.c @@ -0,0 +1,511 @@ +/* + * linux/fs/stat.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include <linux/export.h> +#include <linux/mm.h> +#include <linux/errno.h> +#include <linux/file.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->size = i_size_read(inode); + stat->atime = inode->i_atime; + stat->mtime = inode->i_mtime; + stat->ctime = inode->i_ctime; + stat->blksize = (1 << inode->i_blkbits); + stat->blocks = inode->i_blocks; +} + +EXPORT_SYMBOL(generic_fillattr); + +/** + * vfs_getattr_nosec - getattr without security checks + * @path: file to get attributes from + * @stat: structure to return attributes in + * + * Get attributes without calling security_inode_getattr. + * + * Currently the only caller other than vfs_getattr is internal to the + * filehandle lookup code, which uses only the inode number and returns + * no attributes to any user. Any other code probably wants + * vfs_getattr. + */ +int vfs_getattr_nosec(struct path *path, struct kstat *stat) +{ + struct inode *inode = d_backing_inode(path->dentry); + + if (inode->i_op->getattr) + return inode->i_op->getattr(path->mnt, path->dentry, stat); + + generic_fillattr(inode, stat); + return 0; +} + +EXPORT_SYMBOL(vfs_getattr_nosec); + +int vfs_getattr(struct path *path, struct kstat *stat) +{ + int retval; + + retval = security_inode_getattr(path); + if (retval) + return retval; + return vfs_getattr_nosec(path, stat); +} + +EXPORT_SYMBOL(vfs_getattr); + +int vfs_fstat(unsigned int fd, struct kstat *stat) +{ + struct fd f = fdget_raw(fd); + int error = -EBADF; + + if (f.file) { + error = vfs_getattr(&f.file->f_path, stat); + fdput(f); + } + return error; +} +EXPORT_SYMBOL(vfs_fstat); + +int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat, + int flag) +{ + struct path path; + int error = -EINVAL; + unsigned int lookup_flags = 0; + + if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | + AT_EMPTY_PATH)) != 0) + goto out; + + if (!(flag & AT_SYMLINK_NOFOLLOW)) + lookup_flags |= LOOKUP_FOLLOW; + if (flag & AT_EMPTY_PATH) + lookup_flags |= LOOKUP_EMPTY; +retry: + error = user_path_at(dfd, filename, lookup_flags, &path); + if (error) + goto out; + + error = vfs_getattr(&path, stat); + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } +out: + return error; +} +EXPORT_SYMBOL(vfs_fstatat); + +int vfs_stat(const char __user *name, struct kstat *stat) +{ + return vfs_fstatat(AT_FDCWD, name, stat, 0); +} +EXPORT_SYMBOL(vfs_stat); + +int vfs_lstat(const char __user *name, struct kstat *stat) +{ + return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW); +} +EXPORT_SYMBOL(vfs_lstat); + + +#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, from_kuid_munged(current_user_ns(), stat->uid)); + SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), 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; +} + +SYSCALL_DEFINE2(stat, const char __user *, filename, + struct __old_kernel_stat __user *, statbuf) +{ + struct kstat stat; + int error; + + error = vfs_stat(filename, &stat); + if (error) + return error; + + return cp_old_stat(&stat, statbuf); +} + +SYSCALL_DEFINE2(lstat, const char __user *, filename, + struct __old_kernel_stat __user *, statbuf) +{ + struct kstat stat; + int error; + + error = vfs_lstat(filename, &stat); + if (error) + return error; + + return cp_old_stat(&stat, statbuf); +} + +SYSCALL_DEFINE2(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 */ + +#if BITS_PER_LONG == 32 +# define choose_32_64(a,b) a +#else +# define choose_32_64(a,b) b +#endif + +#define valid_dev(x) choose_32_64(old_valid_dev,new_valid_dev)(x) +#define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x) + +#ifndef INIT_STRUCT_STAT_PADDING +# define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st)) +#endif + +static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) +{ + struct stat tmp; + + if (!valid_dev(stat->dev) || !valid_dev(stat->rdev)) + return -EOVERFLOW; +#if BITS_PER_LONG == 32 + if (stat->size > MAX_NON_LFS) + return -EOVERFLOW; +#endif + + INIT_STRUCT_STAT_PADDING(tmp); + tmp.st_dev = 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, from_kuid_munged(current_user_ns(), stat->uid)); + SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); + tmp.st_rdev = encode_dev(stat->rdev); + 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; +} + +SYSCALL_DEFINE2(newstat, const char __user *, filename, + struct stat __user *, statbuf) +{ + struct kstat stat; + int error = vfs_stat(filename, &stat); + + if (error) + return error; + return cp_new_stat(&stat, statbuf); +} + +SYSCALL_DEFINE2(newlstat, const char __user *, filename, + struct stat __user *, statbuf) +{ + struct kstat stat; + int error; + + error = vfs_lstat(filename, &stat); + if (error) + return error; + + return cp_new_stat(&stat, statbuf); +} + +#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) +SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename, + struct stat __user *, statbuf, int, flag) +{ + struct kstat stat; + int error; + + error = vfs_fstatat(dfd, filename, &stat, flag); + if (error) + return error; + return cp_new_stat(&stat, statbuf); +} +#endif + +SYSCALL_DEFINE2(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; +} + +SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname, + char __user *, buf, int, bufsiz) +{ + struct path path; + int error; + int empty = 0; + unsigned int lookup_flags = LOOKUP_EMPTY; + + if (bufsiz <= 0) + return -EINVAL; + +retry: + error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty); + if (!error) { + struct inode *inode = d_backing_inode(path.dentry); + + error = empty ? -ENOENT : -EINVAL; + if (inode->i_op->readlink) { + error = security_inode_readlink(path.dentry); + if (!error) { + touch_atime(&path); + error = inode->i_op->readlink(path.dentry, + buf, bufsiz); + } + } + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } + } + return error; +} + +SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf, + int, bufsiz) +{ + return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); +} + + +/* ---------- LFS-64 ----------- */ +#if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64) + +#ifndef INIT_STRUCT_STAT64_PADDING +# define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st)) +#endif + +static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) +{ + struct stat64 tmp; + + INIT_STRUCT_STAT64_PADDING(tmp); +#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 = from_kuid_munged(current_user_ns(), stat->uid); + tmp.st_gid = from_kgid_munged(current_user_ns(), 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; +} + +SYSCALL_DEFINE2(stat64, const 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; +} + +SYSCALL_DEFINE2(lstat64, const 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; +} + +SYSCALL_DEFINE2(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; +} + +SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename, + struct stat64 __user *, statbuf, int, flag) +{ + struct kstat stat; + int error; + + error = vfs_fstatat(dfd, filename, &stat, flag); + if (error) + return error; + return cp_new_stat64(&stat, statbuf); +} +#endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */ + +/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */ +void __inode_add_bytes(struct inode *inode, loff_t bytes) +{ + inode->i_blocks += bytes >> 9; + bytes &= 511; + inode->i_bytes += bytes; + if (inode->i_bytes >= 512) { + inode->i_blocks++; + inode->i_bytes -= 512; + } +} + +void inode_add_bytes(struct inode *inode, loff_t bytes) +{ + spin_lock(&inode->i_lock); + __inode_add_bytes(inode, bytes); + spin_unlock(&inode->i_lock); +} + +EXPORT_SYMBOL(inode_add_bytes); + +void __inode_sub_bytes(struct inode *inode, loff_t bytes) +{ + inode->i_blocks -= bytes >> 9; + bytes &= 511; + if (inode->i_bytes < bytes) { + inode->i_blocks--; + inode->i_bytes += 512; + } + inode->i_bytes -= bytes; +} + +EXPORT_SYMBOL(__inode_sub_bytes); + +void inode_sub_bytes(struct inode *inode, loff_t bytes) +{ + spin_lock(&inode->i_lock); + __inode_sub_bytes(inode, 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); |