mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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0f25f0e4ef
Making sure that struct fd instances are destroyed in the same
scope where they'd been created, getting rid of reassignments
and passing them by reference, converting to CLASS(fd{,_pos,_raw}).
We are getting very close to having the memory safety of that stuff
trivial to verify.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull 'struct fd' class updates from Al Viro:
"The bulk of struct fd memory safety stuff
Making sure that struct fd instances are destroyed in the same scope
where they'd been created, getting rid of reassignments and passing
them by reference, converting to CLASS(fd{,_pos,_raw}).
We are getting very close to having the memory safety of that stuff
trivial to verify"
* tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
deal with the last remaing boolean uses of fd_file()
css_set_fork(): switch to CLASS(fd_raw, ...)
memcg_write_event_control(): switch to CLASS(fd)
assorted variants of irqfd setup: convert to CLASS(fd)
do_pollfd(): convert to CLASS(fd)
convert do_select()
convert vfs_dedupe_file_range().
convert cifs_ioctl_copychunk()
convert media_request_get_by_fd()
convert spu_run(2)
switch spufs_calls_{get,put}() to CLASS() use
convert cachestat(2)
convert do_preadv()/do_pwritev()
fdget(), more trivial conversions
fdget(), trivial conversions
privcmd_ioeventfd_assign(): don't open-code eventfd_ctx_fdget()
o2hb_region_dev_store(): avoid goto around fdget()/fdput()
introduce "fd_pos" class, convert fdget_pos() users to it.
fdget_raw() users: switch to CLASS(fd_raw)
convert vmsplice() to CLASS(fd)
...
131 lines
3.7 KiB
C
131 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Wrapper functions for accessing the file_struct fd array.
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*/
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#ifndef __LINUX_FILE_H
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#define __LINUX_FILE_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <linux/posix_types.h>
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#include <linux/errno.h>
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#include <linux/cleanup.h>
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#include <linux/err.h>
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struct file;
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extern void fput(struct file *);
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struct file_operations;
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struct task_struct;
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struct vfsmount;
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struct dentry;
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struct inode;
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struct path;
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extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *,
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const char *, int flags, const struct file_operations *);
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extern struct file *alloc_file_pseudo_noaccount(struct inode *, struct vfsmount *,
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const char *, int flags, const struct file_operations *);
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extern struct file *alloc_file_clone(struct file *, int flags,
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const struct file_operations *);
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/* either a reference to struct file + flags
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* (cloned vs. borrowed, pos locked), with
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* flags stored in lower bits of value,
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* or empty (represented by 0).
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*/
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struct fd {
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unsigned long word;
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};
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#define FDPUT_FPUT 1
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#define FDPUT_POS_UNLOCK 2
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#define fd_file(f) ((struct file *)((f).word & ~(FDPUT_FPUT|FDPUT_POS_UNLOCK)))
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static inline bool fd_empty(struct fd f)
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{
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return unlikely(!f.word);
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}
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#define EMPTY_FD (struct fd){0}
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static inline struct fd BORROWED_FD(struct file *f)
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{
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return (struct fd){(unsigned long)f};
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}
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static inline struct fd CLONED_FD(struct file *f)
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{
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return (struct fd){(unsigned long)f | FDPUT_FPUT};
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}
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static inline void fdput(struct fd fd)
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{
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if (fd.word & FDPUT_FPUT)
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fput(fd_file(fd));
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}
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extern struct file *fget(unsigned int fd);
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extern struct file *fget_raw(unsigned int fd);
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extern struct file *fget_task(struct task_struct *task, unsigned int fd);
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extern struct file *fget_task_next(struct task_struct *task, unsigned int *fd);
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extern void __f_unlock_pos(struct file *);
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struct fd fdget(unsigned int fd);
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struct fd fdget_raw(unsigned int fd);
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struct fd fdget_pos(unsigned int fd);
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static inline void fdput_pos(struct fd f)
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{
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if (f.word & FDPUT_POS_UNLOCK)
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__f_unlock_pos(fd_file(f));
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fdput(f);
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}
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DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd)
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DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd)
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DEFINE_CLASS(fd_pos, struct fd, fdput_pos(_T), fdget_pos(fd), int fd)
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extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);
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extern int replace_fd(unsigned fd, struct file *file, unsigned flags);
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extern void set_close_on_exec(unsigned int fd, int flag);
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extern bool get_close_on_exec(unsigned int fd);
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extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile);
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extern int get_unused_fd_flags(unsigned flags);
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extern void put_unused_fd(unsigned int fd);
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DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T),
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get_unused_fd_flags(flags), unsigned flags)
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DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T))
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/*
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* take_fd() will take care to set @fd to -EBADF ensuring that
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* CLASS(get_unused_fd) won't call put_unused_fd(). This makes it
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* easier to rely on CLASS(get_unused_fd):
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*
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* struct file *f;
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*
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* CLASS(get_unused_fd, fd)(O_CLOEXEC);
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* if (fd < 0)
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* return fd;
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*
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* f = dentry_open(&path, O_RDONLY, current_cred());
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* if (IS_ERR(f))
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* return PTR_ERR(f);
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*
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* fd_install(fd, f);
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* return take_fd(fd);
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*/
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#define take_fd(fd) __get_and_null(fd, -EBADF)
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extern void fd_install(unsigned int fd, struct file *file);
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int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags);
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int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
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extern void flush_delayed_fput(void);
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extern void __fput_sync(struct file *);
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extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
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#endif /* __LINUX_FILE_H */
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