| 1 | /*
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| 2 | * Wrapper functions for accessing the file_struct fd array.
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| 3 | */
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| 4 |
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| 5 | #ifndef __LINUX_FILE_H
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| 6 | #define __LINUX_FILE_H
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| 7 |
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| 8 | #include <linux/types.h>
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| 9 |
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| 10 | struct fd {
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| 11 | struct file *file;
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| 12 | int need_put;
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| 13 | };
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| 14 |
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| 15 | extern void _fput(struct file *);
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| 16 |
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| 17 | /*
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| 18 | * Check whether the specified task has the fd open. Since the task
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| 19 | * may not have a files_struct, we must test for p->files != NULL.
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| 20 | */
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| 21 | extern struct file * fcheck_task(struct task_struct *p, unsigned int fd);
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| 22 |
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| 23 | /*
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| 24 | * Check whether the specified fd has an open file.
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| 25 | */
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| 26 | extern inline struct file * fcheck(unsigned int fd);
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| 27 |
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| 28 | extern inline struct file * frip(unsigned int fd);
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| 29 |
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| 30 | extern inline struct file * fget(unsigned int fd);
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| 31 |
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| 32 | /*
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| 33 | * 23/12/1998 Marcin Dalecki <dalecki@cs.net.pl>:
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| 34 | *
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| 35 | * Since those functions where calling other functions, it was compleatly
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| 36 | * bogous to make them all "extern inline".
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| 37 | *
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| 38 | * The removal of this pseudo optimization saved me scandaleous:
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| 39 | *
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| 40 | * 3756 (i386 arch)
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| 41 | *
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| 42 | * precious bytes from my kernel, even without counting all the code compiled
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| 43 | * as module!
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| 44 | *
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| 45 | * I suspect there are many other similar "optimizations" across the
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| 46 | * kernel...
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| 47 | */
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| 48 | extern inline void fput(struct file * file);
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| 49 | extern void put_filp(struct file *);
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| 50 |
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| 51 | /*
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| 52 | * Install a file pointer in the fd array.
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| 53 | *
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| 54 | * The VFS is full of places where we drop the files lock between
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| 55 | * setting the open_fds bitmap and installing the file in the file
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| 56 | * array. At any such point, we are vulnerable to a dup2() race
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| 57 | * installing a file in the array before us. We need to detect this and
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| 58 | * fput() the struct file we are about to overwrite in this case.
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| 59 | */
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| 60 |
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| 61 | extern inline void fd_install(unsigned int fd, struct file * file);
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| 62 |
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| 63 | #endif /* __LINUX_FILE_H */
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