Something went wrong. Try again.
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Something went wrong. Try again.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256/* SPDX-License-Identifier: GPL-2.0 *//* * 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>#include <linux/errno.h>#include <linux/cleanup.h>#include <linux/err.h>
struct file;
extern void fput(struct file *);
struct file_operations;struct task_struct;struct vfsmount;struct dentry;struct inode;struct path;extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *, const char *, int flags, const struct file_operations *);extern struct file *alloc_file_pseudo_noaccount(struct inode *, struct vfsmount *, const char *, int flags, const struct file_operations *);extern struct file *alloc_file_clone(struct file *, int flags, const struct file_operations *);
/* either a reference to struct file + flags * (cloned vs. borrowed, pos locked), with * flags stored in lower bits of value, * or empty (represented by 0). */struct fd { unsigned long word;};#define FDPUT_FPUT 1#define FDPUT_POS_UNLOCK 2
#define fd_file(f) ((struct file *)((f).word & ~(FDPUT_FPUT|FDPUT_POS_UNLOCK)))static inline bool fd_empty(struct fd f){ return unlikely(!f.word);}
#define EMPTY_FD (struct fd){0}static inline struct fd BORROWED_FD(struct file *f){ return (struct fd){(unsigned long)f};}static inline struct fd CLONED_FD(struct file *f){ return (struct fd){(unsigned long)f | FDPUT_FPUT};}
static inline void fdput(struct fd fd){ if (unlikely(fd.word & FDPUT_FPUT)) fput(fd_file(fd));}
extern struct file *fget(unsigned int fd);extern struct file *fget_raw(unsigned int fd);extern struct file *fget_task(struct task_struct *task, unsigned int fd);extern struct file *fget_task_next(struct task_struct *task, unsigned int *fd);extern void __f_unlock_pos(struct file *);
struct fd fdget(unsigned int fd);struct fd fdget_raw(unsigned int fd);struct fd fdget_pos(unsigned int fd);
static inline void fdput_pos(struct fd f){ if (f.word & FDPUT_POS_UNLOCK) __f_unlock_pos(fd_file(f)); fdput(f);}
DEFINE_CLASS(fd, struct fd, fdput(_T), fdget(fd), int fd)DEFINE_CLASS(fd_raw, struct fd, fdput(_T), fdget_raw(fd), int fd)DEFINE_CLASS(fd_pos, struct fd, fdput_pos(_T), fdget_pos(fd), int 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 int __get_unused_fd_flags(unsigned flags, unsigned long nofile);extern int get_unused_fd_flags(unsigned flags);extern void put_unused_fd(unsigned int fd);
DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T), get_unused_fd_flags(flags), unsigned flags)DEFINE_FREE(fput, struct file *, if (!IS_ERR_OR_NULL(_T)) fput(_T))
/* * take_fd() will take care to set @fd to -EBADF ensuring that * CLASS(get_unused_fd) won't call put_unused_fd(). This makes it * easier to rely on CLASS(get_unused_fd): * * struct file *f; * * CLASS(get_unused_fd, fd)(O_CLOEXEC); * if (fd < 0) * return fd; * * f = dentry_open(&path, O_RDONLY, current_cred()); * if (IS_ERR(f)) * return PTR_ERR(f); * * fd_install(fd, f); * return take_fd(fd); */#define take_fd(fd) __get_and_null(fd, -EBADF)
extern void fd_install(unsigned int fd, struct file *file);
int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags);
int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
extern void flush_delayed_fput(void);extern void __fput_sync(struct file *);
extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
/* * fd_prepare: Combined fd + file allocation cleanup class. * @err: Error code to indicate if allocation succeeded. * @__fd: Allocated fd (may not be accessed directly) * @__file: Allocated struct file pointer (may not be accessed directly) * * Allocates an fd and a file together. On error paths, automatically cleans * up whichever resource was successfully allocated. Allows flexible file * allocation with different functions per usage. * * Do not use directly. */struct fd_prepare { s32 err; s32 __fd; /* do not access directly */ struct file *__file; /* do not access directly */};
/* Typedef for fd_prepare cleanup guards. */typedef struct fd_prepare class_fd_prepare_t;
/* * Accessors for fd_prepare class members. * _Generic() is used for zero-cost type safety. */#define fd_prepare_fd(_fdf) \ (_Generic((_fdf), struct fd_prepare: (_fdf).__fd))
#define fd_prepare_file(_fdf) \ (_Generic((_fdf), struct fd_prepare: (_fdf).__file))
/* Do not use directly. */static inline void class_fd_prepare_destructor(const struct fd_prepare *fdf){ if (unlikely(fdf->__fd >= 0)) put_unused_fd(fdf->__fd); if (unlikely(!IS_ERR_OR_NULL(fdf->__file))) fput(fdf->__file);}
/* Do not use directly. */static inline int class_fd_prepare_lock_err(const struct fd_prepare *fdf){ if (unlikely(fdf->err)) return fdf->err; if (unlikely(fdf->__fd < 0)) return fdf->__fd; if (unlikely(IS_ERR(fdf->__file))) return PTR_ERR(fdf->__file); if (unlikely(!fdf->__file)) return -ENOMEM; return 0;}
/* * __FD_PREPARE_INIT - Helper to initialize fd_prepare class. * @_fd_flags: flags for get_unused_fd_flags() * @_file_owned: expression that returns struct file * * * Returns a struct fd_prepare with fd, file, and err set. * If fd allocation fails, fd will be negative and err will be set. If * fd succeeds but file_init_expr fails, file will be ERR_PTR and err * will be set. The err field is the single source of truth for error * checking. */#define __FD_PREPARE_INIT(_fd_flags, _file_owned) \ ({ \ struct fd_prepare fdf = { \ .__fd = get_unused_fd_flags((_fd_flags)), \ }; \ if (likely(fdf.__fd >= 0)) \ fdf.__file = (_file_owned); \ fdf.err = ACQUIRE_ERR(fd_prepare, &fdf); \ fdf; \ })
/* * FD_PREPARE - Macro to declare and initialize an fd_prepare variable. * * Declares and initializes an fd_prepare variable with automatic * cleanup. No separate scope required - cleanup happens when variable * goes out of scope. * * @_fdf: name of struct fd_prepare variable to define * @_fd_flags: flags for get_unused_fd_flags() * @_file_owned: struct file to take ownership of (can be expression) */#define FD_PREPARE(_fdf, _fd_flags, _file_owned) \ CLASS_INIT(fd_prepare, _fdf, __FD_PREPARE_INIT(_fd_flags, _file_owned))
/* * fd_publish - Publish prepared fd and file to the fd table. * @_fdf: struct fd_prepare variable */#define fd_publish(_fdf) \ ({ \ struct fd_prepare *fdp = &(_fdf); \ VFS_WARN_ON_ONCE(fdp->err); \ VFS_WARN_ON_ONCE(fdp->__fd < 0); \ VFS_WARN_ON_ONCE(IS_ERR_OR_NULL(fdp->__file)); \ fd_install(fdp->__fd, fdp->__file); \ retain_and_null_ptr(fdp->__file); \ take_fd(fdp->__fd); \ })
/* Do not use directly. */#define __FD_ADD(_fdf, _fd_flags, _file_owned) \ ({ \ FD_PREPARE(_fdf, _fd_flags, _file_owned); \ s32 ret = _fdf.err; \ if (likely(!ret)) \ ret = fd_publish(_fdf); \ ret; \ })
/* * FD_ADD - Allocate and install an fd and file in one step. * @_fd_flags: flags for get_unused_fd_flags() * @_file_owned: struct file to take ownership of * * Returns the allocated fd number, or negative error code on failure. */#define FD_ADD(_fd_flags, _file_owned) \ __FD_ADD(__UNIQUE_ID(fd_prepare), _fd_flags, _file_owned)
#endif /* __LINUX_FILE_H */