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111 lines
2.7 KiB
111 lines
2.7 KiB
/* |
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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/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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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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struct rcu_head rcu; |
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struct fdtable *next; |
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}; |
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static inline bool close_on_exec(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(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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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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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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struct file __rcu * fd_array[NR_OPEN_DEFAULT]; |
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}; |
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#define rcu_dereference_check_fdtable(files, fdtfd) \ |
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(rcu_dereference_check((fdtfd), \ |
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lockdep_is_held(&(files)->file_lock) || \ |
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atomic_read(&(files)->count) == 1 || \ |
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rcu_my_thread_group_empty())) |
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#define files_fdtable(files) \ |
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(rcu_dereference_check_fdtable((files), (files)->fdt)) |
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struct file_operations; |
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struct vfsmount; |
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struct dentry; |
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extern void __init files_defer_init(void); |
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static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) |
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{ |
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struct file * file = NULL; |
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struct fdtable *fdt = files_fdtable(files); |
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if (fd < fdt->max_fds) |
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file = rcu_dereference_check_fdtable(files, fdt->fd[fd]); |
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return file; |
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} |
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/* |
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* Check whether the specified fd has an open file. |
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*/ |
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#define fcheck(fd) fcheck_files(current->files, fd) |
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struct task_struct; |
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struct files_struct *get_files_struct(struct task_struct *); |
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void put_files_struct(struct files_struct *fs); |
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void reset_files_struct(struct files_struct *); |
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int unshare_files(struct files_struct **); |
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struct files_struct *dup_fd(struct files_struct *, int *); |
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void do_close_on_exec(struct files_struct *); |
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extern int __alloc_fd(struct files_struct *files, |
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unsigned start, unsigned end, unsigned flags); |
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extern void __fd_install(struct files_struct *files, |
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unsigned int fd, struct file *file); |
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extern int __close_fd(struct files_struct *files, |
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unsigned int fd); |
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extern struct kmem_cache *files_cachep; |
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#endif /* __LINUX_FDTABLE_H */
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