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/* SPDX-License-Identifier: GPL-2.0 */ | |
/* | |
* descriptor table internals; you almost certainly want file.h instead. | |
*/ | |
#ifndef __LINUX_FDTABLE_H | |
#define __LINUX_FDTABLE_H | |
#include <linux/posix_types.h> | |
#include <linux/compiler.h> | |
#include <linux/spinlock.h> | |
#include <linux/rcupdate.h> | |
#include <linux/nospec.h> | |
#include <linux/types.h> | |
#include <linux/init.h> | |
#include <linux/fs.h> | |
#include <linux/atomic.h> | |
/* | |
* The default fd array needs to be at least BITS_PER_LONG, | |
* as this is the granularity returned by copy_fdset(). | |
*/ | |
#define NR_OPEN_DEFAULT BITS_PER_LONG | |
#define NR_OPEN_MAX ~0U | |
struct fdtable { | |
unsigned int max_fds; | |
struct file __rcu **fd; /* current fd array */ | |
unsigned long *close_on_exec; | |
unsigned long *open_fds; | |
unsigned long *full_fds_bits; | |
struct rcu_head rcu; | |
}; | |
static inline bool close_on_exec(unsigned int fd, const struct fdtable *fdt) | |
{ | |
return test_bit(fd, fdt->close_on_exec); | |
} | |
static inline bool fd_is_open(unsigned int fd, const struct fdtable *fdt) | |
{ | |
return test_bit(fd, fdt->open_fds); | |
} | |
/* | |
* Open file table structure | |
*/ | |
struct files_struct { | |
/* | |
* read mostly part | |
*/ | |
atomic_t count; | |
bool resize_in_progress; | |
wait_queue_head_t resize_wait; | |
struct fdtable __rcu *fdt; | |
struct fdtable fdtab; | |
/* | |
* written part on a separate cache line in SMP | |
*/ | |
spinlock_t file_lock ____cacheline_aligned_in_smp; | |
unsigned int next_fd; | |
unsigned long close_on_exec_init[1]; | |
unsigned long open_fds_init[1]; | |
unsigned long full_fds_bits_init[1]; | |
struct file __rcu * fd_array[NR_OPEN_DEFAULT]; | |
}; | |
struct file_operations; | |
struct vfsmount; | |
struct dentry; | |
#define rcu_dereference_check_fdtable(files, fdtfd) \ | |
rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock)) | |
#define files_fdtable(files) \ | |
rcu_dereference_check_fdtable((files), (files)->fdt) | |
/* | |
* The caller must ensure that fd table isn't shared or hold rcu or file lock | |
*/ | |
static inline struct file *files_lookup_fd_raw(struct files_struct *files, unsigned int fd) | |
{ | |
struct fdtable *fdt = rcu_dereference_raw(files->fdt); | |
if (fd < fdt->max_fds) { | |
fd = array_index_nospec(fd, fdt->max_fds); | |
return rcu_dereference_raw(fdt->fd[fd]); | |
} | |
return NULL; | |
} | |
static inline struct file *files_lookup_fd_locked(struct files_struct *files, unsigned int fd) | |
{ | |
RCU_LOCKDEP_WARN(!lockdep_is_held(&files->file_lock), | |
"suspicious rcu_dereference_check() usage"); | |
return files_lookup_fd_raw(files, fd); | |
} | |
static inline struct file *files_lookup_fd_rcu(struct files_struct *files, unsigned int fd) | |
{ | |
RCU_LOCKDEP_WARN(!rcu_read_lock_held(), | |
"suspicious rcu_dereference_check() usage"); | |
return files_lookup_fd_raw(files, fd); | |
} | |
static inline struct file *lookup_fd_rcu(unsigned int fd) | |
{ | |
return files_lookup_fd_rcu(current->files, fd); | |
} | |
struct file *task_lookup_fd_rcu(struct task_struct *task, unsigned int fd); | |
struct file *task_lookup_next_fd_rcu(struct task_struct *task, unsigned int *fd); | |
struct task_struct; | |
void put_files_struct(struct files_struct *fs); | |
int unshare_files(void); | |
struct files_struct *dup_fd(struct files_struct *, unsigned, int *) __latent_entropy; | |
void do_close_on_exec(struct files_struct *); | |
int iterate_fd(struct files_struct *, unsigned, | |
int (*)(const void *, struct file *, unsigned), | |
const void *); | |
extern int close_fd(unsigned int fd); | |
extern int __close_range(unsigned int fd, unsigned int max_fd, unsigned int flags); | |
extern int close_fd_get_file(unsigned int fd, struct file **res); | |
extern int unshare_fd(unsigned long unshare_flags, unsigned int max_fds, | |
struct files_struct **new_fdp); | |
extern struct kmem_cache *files_cachep; | |
#endif /* __LINUX_FDTABLE_H */ |