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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 struct file *close_fd_get_file(unsigned int fd);
- 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 */
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