b0d9ea1308
The fdtable infrastructure provides a possibility to prevent concurrent access to file descriptor. Use that functionality in eventfd API. Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
103 lines
2.2 KiB
C
103 lines
2.2 KiB
C
/*
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* Copyright (c) 2020 Tobias Svehagen
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#ifndef ZEPHYR_INCLUDE_POSIX_SYS_EVENTFD_H_
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#define ZEPHYR_INCLUDE_POSIX_SYS_EVENTFD_H_
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#include <zephyr.h>
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#include <sys/fdtable.h>
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#include <sys/types.h>
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#include <fcntl.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define EFD_IN_USE 0x1
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#define EFD_SEMAPHORE 0x2
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#define EFD_NONBLOCK O_NONBLOCK
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#define EFD_FLAGS_SET (EFD_SEMAPHORE | EFD_NONBLOCK)
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typedef uint64_t eventfd_t;
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/**
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* @brief Create a file descriptor for event notification
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*
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* The returned file descriptor can be used with POSIX read/write calls or
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* with the eventfd_read/eventfd_write functions.
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*
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* It also supports polling and by including an eventfd in a call to poll,
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* it is possible to signal and wake the polling thread by simply writing to
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* the eventfd.
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*
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* When using read() and write() on an eventfd, the size must always be at
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* least 8 bytes or the operation will fail with EINVAL.
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*
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* @return New eventfd file descriptor on success, -1 on error
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*/
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int eventfd(unsigned int initval, int flags);
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/**
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* @brief Read from an eventfd
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*
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* If call is successful, the value parameter will have the value 1
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*
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* @param fd File descriptor
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* @param value Pointer for storing the read value
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*
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* @return 0 on success, -1 on error
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*/
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static inline int eventfd_read(int fd, eventfd_t *value)
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{
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const struct fd_op_vtable *efd_vtable;
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struct k_mutex *lock;
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ssize_t ret;
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void *obj;
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obj = z_get_fd_obj_and_vtable(fd, &efd_vtable, &lock);
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(void)k_mutex_lock(lock, K_FOREVER);
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ret = efd_vtable->read(obj, value, sizeof(*value));
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k_mutex_unlock(lock);
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return ret == sizeof(eventfd_t) ? 0 : -1;
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}
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/**
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* @brief Write to an eventfd
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*
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* @param fd File descriptor
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* @param value Value to write
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*
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* @return 0 on success, -1 on error
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*/
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static inline int eventfd_write(int fd, eventfd_t value)
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{
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const struct fd_op_vtable *efd_vtable;
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struct k_mutex *lock;
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ssize_t ret;
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void *obj;
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obj = z_get_fd_obj_and_vtable(fd, &efd_vtable, &lock);
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(void)k_mutex_lock(lock, K_FOREVER);
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ret = efd_vtable->write(obj, &value, sizeof(value));
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k_mutex_unlock(lock);
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return ret == sizeof(eventfd_t) ? 0 : -1;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* ZEPHYR_INCLUDE_POSIX_SYS_EVENTFD_H_ */
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