fs/stat.c

Source file repositories/reference/linux-study-clean/fs/stat.c

File Facts

System
Linux kernel
Corpus path
fs/stat.c
Extension
.c
Size
27228 bytes
Lines
969
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: syscall or user/kernel boundary
Status
core implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

SYSCALL_DEFINE2(stat, const char __user *, filename,
		struct __old_kernel_stat __user *, statbuf)
{
	struct kstat stat;
	int error;

	error = vfs_stat(filename, &stat);
	if (unlikely(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 (unlikely(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;

	error = vfs_fstat(fd, &stat);
	if (unlikely(error))
		return error;

	return cp_old_stat(&stat, statbuf);
}

#endif /* __ARCH_WANT_OLD_STAT */

#ifdef __ARCH_WANT_NEW_STAT

#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 (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
		return -EOVERFLOW;
	if (sizeof(tmp.st_rdev) < 4 && !old_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 = new_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 = new_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;

Annotation

Implementation Notes