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