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linux-next/include/linux/file.h
Yann Droneaud f938612dd9 include/linux/file.h: remove get_unused_fd() macro
Macro get_unused_fd() is used to allocate a file descriptor with default
flags.  Those default flags (0) don't enable close-on-exec.

This can be seen as an unsafe default: in most case close-on-exec should
be enabled to not leak file descriptor across exec().

It would be better to have a "safer" default set of flags, eg.  O_CLOEXEC
must be used to enable close-on-exec.

Instead this patch removes get_unused_fd() so that out of tree modules
won't be affect by a runtime behavor change which might introduce other
kind of bugs: it's better to catch the change at build time, making it
easier to fix.

Removing the macro will also promote use of get_unused_fd_flags() (or
anon_inode_getfd()) with flags provided by userspace.  Or, if flags cannot
be given by userspace, with flags set to O_CLOEXEC by default.

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10 17:41:10 -08:00

77 lines
1.7 KiB
C

/*
* Wrapper functions for accessing the file_struct fd array.
*/
#ifndef __LINUX_FILE_H
#define __LINUX_FILE_H
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/posix_types.h>
struct file;
extern void fput(struct file *);
struct file_operations;
struct vfsmount;
struct dentry;
struct path;
extern struct file *alloc_file(struct path *, fmode_t mode,
const struct file_operations *fop);
static inline void fput_light(struct file *file, int fput_needed)
{
if (fput_needed)
fput(file);
}
struct fd {
struct file *file;
unsigned int flags;
};
#define FDPUT_FPUT 1
#define FDPUT_POS_UNLOCK 2
static inline void fdput(struct fd fd)
{
if (fd.flags & FDPUT_FPUT)
fput(fd.file);
}
extern struct file *fget(unsigned int fd);
extern struct file *fget_raw(unsigned int fd);
extern unsigned long __fdget(unsigned int fd);
extern unsigned long __fdget_raw(unsigned int fd);
extern unsigned long __fdget_pos(unsigned int fd);
static inline struct fd __to_fd(unsigned long v)
{
return (struct fd){(struct file *)(v & ~3),v & 3};
}
static inline struct fd fdget(unsigned int fd)
{
return __to_fd(__fdget(fd));
}
static inline struct fd fdget_raw(unsigned int fd)
{
return __to_fd(__fdget_raw(fd));
}
extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);
extern int replace_fd(unsigned fd, struct file *file, unsigned flags);
extern void set_close_on_exec(unsigned int fd, int flag);
extern bool get_close_on_exec(unsigned int fd);
extern void put_filp(struct file *);
extern int get_unused_fd_flags(unsigned flags);
extern void put_unused_fd(unsigned int fd);
extern void fd_install(unsigned int fd, struct file *file);
extern void flush_delayed_fput(void);
extern void __fput_sync(struct file *);
#endif /* __LINUX_FILE_H */