diff options
Diffstat (limited to 'cras/src/common/cras_shm.h')
| -rw-r--r-- | cras/src/common/cras_shm.h | 659 |
1 files changed, 0 insertions, 659 deletions
diff --git a/cras/src/common/cras_shm.h b/cras/src/common/cras_shm.h deleted file mode 100644 index 47786c3b..00000000 --- a/cras/src/common/cras_shm.h +++ /dev/null @@ -1,659 +0,0 @@ -/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved. - * Use of this source code is governed by a BSD-style license that can be - * found in the LICENSE file. - */ - -#ifndef CRAS_SHM_H_ -#define CRAS_SHM_H_ - -#include <assert.h> -#include <stdint.h> -#include <sys/mman.h> -#include <sys/param.h> - -#include "cras_types.h" -#include "cras_util.h" - -#define CRAS_NUM_SHM_BUFFERS 2U /* double buffer */ -#define CRAS_SHM_BUFFERS_MASK (CRAS_NUM_SHM_BUFFERS - 1) - -/* Configuration of the shm area. - * - * used_size - The size in bytes of the sample area being actively used. - * frame_bytes - The size of each frame in bytes. - */ -struct __attribute__((__packed__)) cras_audio_shm_config { - uint32_t used_size; - uint32_t frame_bytes; -}; - -/* Structure containing stream metadata shared between client and server. - * - * config - Size config data. A copy of the config shared with clients. - * read_buf_idx - index of the current buffer to read from (0 or 1 if double - * buffered). - * write_buf_idx - index of the current buffer to write to (0 or 1 if double - * buffered). - * read_offset - offset of the next sample to read (one per buffer). - * write_offset - offset of the next sample to write (one per buffer). - * write_in_progress - non-zero when a write is in progress. - * volume_scaler - volume scaling factor (0.0-1.0). - * muted - bool, true if stream should be muted. - * num_overruns - Starting at 0 this is incremented very time data is over - * written because too much accumulated before a read. - * ts - For capture, the time stamp of the next sample at read_index. For - * playback, this is the time that the next sample written will be played. - * This is only valid in audio callbacks. - * buffer_offset - Offset of each buffer from start of samples area. - * Valid range: 0 <= buffer_offset <= shm->samples_info.length - */ -struct __attribute__((__packed__)) cras_audio_shm_header { - struct cras_audio_shm_config config; - uint32_t read_buf_idx; /* use buffer A or B */ - uint32_t write_buf_idx; - uint32_t read_offset[CRAS_NUM_SHM_BUFFERS]; - uint32_t write_offset[CRAS_NUM_SHM_BUFFERS]; - int32_t write_in_progress[CRAS_NUM_SHM_BUFFERS]; - float volume_scaler; - int32_t mute; - int32_t callback_pending; - uint32_t num_overruns; - struct cras_timespec ts; - uint64_t buffer_offset[CRAS_NUM_SHM_BUFFERS]; -}; - -/* Returns the number of bytes needed to hold a cras_audio_shm_header. */ -static inline uint32_t cras_shm_header_size() -{ - return sizeof(struct cras_audio_shm_header); -} - -/* Returns the number of bytes needed to hold the samples area for an audio - * shm with the given used_size */ -static inline uint32_t cras_shm_calculate_samples_size(uint32_t used_size) -{ - return used_size * CRAS_NUM_SHM_BUFFERS; -} - -/* Holds identifiers for a shm segment. All valid cras_shm_info objects will - * have an fd and a length, and they may have the name of the shm file as well. - * - * fd - File descriptor to access shm (shared between client/server). - * name - Name of the shm area. May be empty. - * length - Size of the shm region. - */ -struct cras_shm_info { - int fd; - char name[NAME_MAX]; - size_t length; -}; - -/* Initializes a cras_shm_info to be used as the backing shared memory for a - * cras_audio_shm. - * - * shm_name - the name of the shm area to create. - * length - the length of the shm area to create. - * info_out - pointer where the created cras_shm_info will be stored. - */ -int cras_shm_info_init(const char *shm_name, uint32_t length, - struct cras_shm_info *info_out); - -/* Initializes a cras_shm_info to be used as the backing shared memory for a - * cras_audio_shm. - * - * fd - file descriptor for the shm to be used. fd must be closed after - * calling this function. - * length - the size of the shm referenced by fd. - * info_out - pointer where the created cras_shm_info will be stored. - */ -int cras_shm_info_init_with_fd(int fd, size_t length, - struct cras_shm_info *info_out); - -/* Cleans up the resources for a cras_shm_info returned from cras_shm_info_init. - * - * info - the cras_shm_info to cleanup. - */ -void cras_shm_info_cleanup(struct cras_shm_info *info); - -/* Structure that holds the config for and a pointer to the audio shm header and - * samples area. - * - * config - Size config data, kept separate so it can be checked. - * header_info - fd, name, and length of shm containing header. - * header - Shm region containing audio metadata - * samples_info - fd, name, and length of shm containing samples. - * samples - Shm region containing audio data. - */ -struct cras_audio_shm { - struct cras_audio_shm_config config; - struct cras_shm_info header_info; - struct cras_audio_shm_header *header; - struct cras_shm_info samples_info; - uint8_t *samples; -}; - -/* Sets up a cras_audio_shm given info about the shared memory to use - * - * header_info - the underlying shm area to use for the header. The shm - * will be managed by the created cras_audio_shm object. - * The header_info parameter will be returned to an uninitialized - * state, and the client need not call cras_shm_info_destroy. - * samples_info - the underlying shm area to use for the samples. The shm - * will be managed by the created cras_audio_shm object. - * The samples_info parameter will be returned to an - * uninitialized state, and the client need not call - * cras_shm_info_destroy. - * samples_prot - the mapping protections to use when mapping samples. Allowed - * values are PROT_READ or PROT_WRITE. - * shm_out - pointer where the created cras_audio_shm will be stored. - * - * Returns 0 on success or a negative error code on failure. - */ -int cras_audio_shm_create(struct cras_shm_info *header_info, - struct cras_shm_info *samples_info, int samples_prot, - struct cras_audio_shm **shm_out); - -/* Destroys a cras_audio_shm returned from cras_audio_shm_create. - * - * shm - the cras_audio_shm to destroy. - */ -void cras_audio_shm_destroy(struct cras_audio_shm *shm); - -/* Limit a buffer offset to within the samples area size. */ -static inline unsigned -cras_shm_get_checked_buffer_offset(const struct cras_audio_shm *shm, - uint32_t buf_idx) -{ - unsigned buffer_offset = shm->header->buffer_offset[buf_idx]; - - /* Cap buffer_offset at the length of the samples area */ - return MIN(buffer_offset, shm->samples_info.length); -} - -/* Get a pointer to the buffer at idx. */ -static inline uint8_t *cras_shm_buff_for_idx(const struct cras_audio_shm *shm, - size_t idx) -{ - assert_on_compile_is_power_of_2(CRAS_NUM_SHM_BUFFERS); - idx = idx & CRAS_SHM_BUFFERS_MASK; - - return shm->samples + cras_shm_get_checked_buffer_offset(shm, idx); -} - -/* Limit a read offset to within the buffer size. */ -static inline unsigned -cras_shm_get_checked_read_offset(const struct cras_audio_shm *shm, - uint32_t buf_idx) -{ - unsigned buffer_offset = - cras_shm_get_checked_buffer_offset(shm, buf_idx); - unsigned read_offset = shm->header->read_offset[buf_idx]; - - /* The read_offset is allowed to be the total size, indicating that the - * buffer is full. If read pointer is invalid assume it is at the - * beginning. */ - if (read_offset > shm->config.used_size) - return 0; - if (buffer_offset + read_offset > shm->samples_info.length) - return 0; - return read_offset; -} - -/* Limit a write offset to within the buffer size. */ -static inline unsigned -cras_shm_get_checked_write_offset(const struct cras_audio_shm *shm, - uint32_t buf_idx) -{ - unsigned write_offset = shm->header->write_offset[buf_idx]; - unsigned buffer_offset = - cras_shm_get_checked_buffer_offset(shm, buf_idx); - - /* The write_offset is allowed to be the total size, indicating that the - * buffer is full. If write pointer is past used size, assume it is at - * used size. */ - write_offset = MIN(write_offset, shm->config.used_size); - - /* If the buffer offset plus the write offset overruns the samples area, - * return the longest valid write_offset */ - if (buffer_offset + write_offset > shm->samples_info.length) - return shm->samples_info.length - buffer_offset; - return write_offset; -} - -/* Get the number of frames readable in current read buffer */ -static inline unsigned -cras_shm_get_curr_read_frames(const struct cras_audio_shm *shm) -{ - unsigned buf_idx = shm->header->read_buf_idx & CRAS_SHM_BUFFERS_MASK; - unsigned read_offset, write_offset; - - read_offset = cras_shm_get_checked_read_offset(shm, buf_idx); - write_offset = cras_shm_get_checked_write_offset(shm, buf_idx); - - if (read_offset > write_offset) - return 0; - else - return (write_offset - read_offset) / shm->config.frame_bytes; -} - -/* Get the base of the current read buffer. */ -static inline uint8_t * -cras_shm_get_read_buffer_base(const struct cras_audio_shm *shm) -{ - unsigned i = shm->header->read_buf_idx & CRAS_SHM_BUFFERS_MASK; - return cras_shm_buff_for_idx(shm, i); -} - -/* Get the base of the current write buffer. */ -static inline uint8_t * -cras_shm_get_write_buffer_base(const struct cras_audio_shm *shm) -{ - unsigned i = shm->header->write_buf_idx & CRAS_SHM_BUFFERS_MASK; - - return cras_shm_buff_for_idx(shm, i); -} - -/* Get a pointer to the next buffer to write */ -static inline uint8_t * -cras_shm_get_writeable_frames(const struct cras_audio_shm *shm, - unsigned limit_frames, unsigned *frames) -{ - unsigned buf_idx = shm->header->write_buf_idx & CRAS_SHM_BUFFERS_MASK; - unsigned write_offset; - const unsigned frame_bytes = shm->config.frame_bytes; - unsigned written; - - write_offset = cras_shm_get_checked_write_offset(shm, buf_idx); - written = write_offset / frame_bytes; - if (frames) { - if (limit_frames >= written) - *frames = limit_frames - written; - else - *frames = 0; - } - - return cras_shm_buff_for_idx(shm, buf_idx) + write_offset; -} - -/* Get a pointer to the current read buffer plus an offset. The offset might be - * in the next buffer. 'frames' is filled with the number of frames that can be - * copied from the returned buffer. - */ -static inline uint8_t * -cras_shm_get_readable_frames(const struct cras_audio_shm *shm, size_t offset, - size_t *frames) -{ - unsigned buf_idx = shm->header->read_buf_idx & CRAS_SHM_BUFFERS_MASK; - unsigned read_offset, write_offset, final_offset; - - assert(frames != NULL); - - read_offset = cras_shm_get_checked_read_offset(shm, buf_idx); - write_offset = cras_shm_get_checked_write_offset(shm, buf_idx); - final_offset = read_offset + offset * shm->config.frame_bytes; - if (final_offset >= write_offset) { - final_offset -= write_offset; - assert_on_compile_is_power_of_2(CRAS_NUM_SHM_BUFFERS); - buf_idx = (buf_idx + 1) & CRAS_SHM_BUFFERS_MASK; - write_offset = cras_shm_get_checked_write_offset(shm, buf_idx); - } - if (final_offset >= write_offset) { - /* Past end of samples. */ - *frames = 0; - return NULL; - } - *frames = (write_offset - final_offset) / shm->config.frame_bytes; - return cras_shm_buff_for_idx(shm, buf_idx) + final_offset; -} - -/* How many bytes are queued? */ -static inline size_t cras_shm_get_bytes_queued(const struct cras_audio_shm *shm) -{ - size_t total, i; - const unsigned used_size = shm->config.used_size; - - total = 0; - for (i = 0; i < CRAS_NUM_SHM_BUFFERS; i++) { - unsigned read_offset, write_offset; - - read_offset = MIN(shm->header->read_offset[i], used_size); - write_offset = MIN(shm->header->write_offset[i], used_size); - - if (write_offset > read_offset) - total += write_offset - read_offset; - } - return total; -} - -/* How many frames are queued? */ -static inline int cras_shm_get_frames(const struct cras_audio_shm *shm) -{ - size_t bytes; - - bytes = cras_shm_get_bytes_queued(shm); - if (bytes % shm->config.frame_bytes != 0) - return -EIO; - return bytes / shm->config.frame_bytes; -} - -/* How many frames in the current buffer? */ -static inline size_t -cras_shm_get_frames_in_curr_buffer(const struct cras_audio_shm *shm) -{ - size_t buf_idx = shm->header->read_buf_idx & CRAS_SHM_BUFFERS_MASK; - unsigned read_offset, write_offset; - const unsigned used_size = shm->config.used_size; - - read_offset = MIN(shm->header->read_offset[buf_idx], used_size); - write_offset = MIN(shm->header->write_offset[buf_idx], used_size); - - if (write_offset <= read_offset) - return 0; - - return (write_offset - read_offset) / shm->config.frame_bytes; -} - -/* Return 1 if there is an empty buffer in the list. */ -static inline int cras_shm_is_buffer_available(const struct cras_audio_shm *shm) -{ - size_t buf_idx = shm->header->write_buf_idx & CRAS_SHM_BUFFERS_MASK; - - return (shm->header->write_offset[buf_idx] == 0); -} - -/* How many are available to be written? */ -static inline size_t -cras_shm_get_num_writeable(const struct cras_audio_shm *shm) -{ - /* Not allowed to write to a buffer twice. */ - if (!cras_shm_is_buffer_available(shm)) - return 0; - - return shm->config.used_size / shm->config.frame_bytes; -} - -/* Flags an overrun if writing would cause one and reset the write offset. - * Return 1 if overrun happens, otherwise return 0. */ -static inline int cras_shm_check_write_overrun(struct cras_audio_shm *shm) -{ - int ret = 0; - size_t write_buf_idx = - shm->header->write_buf_idx & CRAS_SHM_BUFFERS_MASK; - - if (!shm->header->write_in_progress[write_buf_idx]) { - unsigned int used_size = shm->config.used_size; - - if (shm->header->write_offset[write_buf_idx]) { - shm->header->num_overruns++; /* Will over-write unread */ - ret = 1; - } - - memset(cras_shm_buff_for_idx(shm, write_buf_idx), 0, used_size); - - shm->header->write_in_progress[write_buf_idx] = 1; - shm->header->write_offset[write_buf_idx] = 0; - } - return ret; -} - -/* Increment the write pointer for the current buffer. */ -static inline void cras_shm_buffer_written(struct cras_audio_shm *shm, - size_t frames) -{ - size_t buf_idx = shm->header->write_buf_idx & CRAS_SHM_BUFFERS_MASK; - - if (frames == 0) - return; - - shm->header->write_offset[buf_idx] += frames * shm->config.frame_bytes; - shm->header->read_offset[buf_idx] = 0; -} - -/* Returns the number of frames that have been written to the current buffer. */ -static inline unsigned int -cras_shm_frames_written(const struct cras_audio_shm *shm) -{ - size_t buf_idx = shm->header->write_buf_idx & CRAS_SHM_BUFFERS_MASK; - - return shm->header->write_offset[buf_idx] / shm->config.frame_bytes; -} - -/* Signals the writing to this buffer is complete and moves to the next one. */ -static inline void cras_shm_buffer_write_complete(struct cras_audio_shm *shm) -{ - size_t buf_idx = shm->header->write_buf_idx & CRAS_SHM_BUFFERS_MASK; - - shm->header->write_in_progress[buf_idx] = 0; - - assert_on_compile_is_power_of_2(CRAS_NUM_SHM_BUFFERS); - buf_idx = (buf_idx + 1) & CRAS_SHM_BUFFERS_MASK; - shm->header->write_buf_idx = buf_idx; -} - -/* Set the write pointer for the current buffer and complete the write. */ -static inline void cras_shm_buffer_written_start(struct cras_audio_shm *shm, - size_t frames) -{ - size_t buf_idx = shm->header->write_buf_idx & CRAS_SHM_BUFFERS_MASK; - - shm->header->write_offset[buf_idx] = frames * shm->config.frame_bytes; - shm->header->read_offset[buf_idx] = 0; - cras_shm_buffer_write_complete(shm); -} - -/* Increment the read pointer. If it goes past the write pointer for this - * buffer, move to the next buffer. */ -static inline void cras_shm_buffer_read(struct cras_audio_shm *shm, - size_t frames) -{ - size_t buf_idx = shm->header->read_buf_idx & CRAS_SHM_BUFFERS_MASK; - size_t remainder; - struct cras_audio_shm_header *header = shm->header; - struct cras_audio_shm_config *config = &shm->config; - - if (frames == 0) - return; - - header->read_offset[buf_idx] += frames * config->frame_bytes; - if (header->read_offset[buf_idx] >= header->write_offset[buf_idx]) { - remainder = header->read_offset[buf_idx] - - header->write_offset[buf_idx]; - header->read_offset[buf_idx] = 0; - header->write_offset[buf_idx] = 0; - assert_on_compile_is_power_of_2(CRAS_NUM_SHM_BUFFERS); - buf_idx = (buf_idx + 1) & CRAS_SHM_BUFFERS_MASK; - if (remainder < header->write_offset[buf_idx]) { - header->read_offset[buf_idx] = remainder; - } else if (remainder) { - /* Read all of this buffer too. */ - header->write_offset[buf_idx] = 0; - buf_idx = (buf_idx + 1) & CRAS_SHM_BUFFERS_MASK; - } - header->read_buf_idx = buf_idx; - } -} - -/* Read from the current buffer. This is similar to cras_shm_buffer_read(), but - * it doesn't check for the case we may read from two buffers. */ -static inline void cras_shm_buffer_read_current(struct cras_audio_shm *shm, - size_t frames) -{ - size_t buf_idx = shm->header->read_buf_idx & CRAS_SHM_BUFFERS_MASK; - struct cras_audio_shm_header *header = shm->header; - struct cras_audio_shm_config *config = &shm->config; - - header->read_offset[buf_idx] += frames * config->frame_bytes; - if (header->read_offset[buf_idx] >= header->write_offset[buf_idx]) { - header->read_offset[buf_idx] = 0; - header->write_offset[buf_idx] = 0; - buf_idx = (buf_idx + 1) & CRAS_SHM_BUFFERS_MASK; - header->read_buf_idx = buf_idx; - } -} - -/* Sets the volume for the stream. The volume level is a scaling factor that - * will be applied to the stream before mixing. */ -static inline void cras_shm_set_volume_scaler(struct cras_audio_shm *shm, - float volume_scaler) -{ - volume_scaler = MAX(volume_scaler, 0.0); - shm->header->volume_scaler = MIN(volume_scaler, 1.0); -} - -/* Returns the volume of the stream(0.0-1.0). */ -static inline float cras_shm_get_volume_scaler(const struct cras_audio_shm *shm) -{ - return shm->header->volume_scaler; -} - -/* Indicates that the stream should be muted/unmuted */ -static inline void cras_shm_set_mute(struct cras_audio_shm *shm, size_t mute) -{ - shm->header->mute = !!mute; -} - -/* Returns the mute state of the stream. 0 if not muted, non-zero if muted. */ -static inline size_t cras_shm_get_mute(const struct cras_audio_shm *shm) -{ - return shm->header->mute; -} - -/* Sets the size of a frame in bytes. */ -static inline void cras_shm_set_frame_bytes(struct cras_audio_shm *shm, - unsigned frame_bytes) -{ - shm->config.frame_bytes = frame_bytes; - if (shm->header) - shm->header->config.frame_bytes = frame_bytes; -} - -/* Returns the size of a frame in bytes. */ -static inline unsigned cras_shm_frame_bytes(const struct cras_audio_shm *shm) -{ - return shm->config.frame_bytes; -} - -/* Sets if a callback is pending with the client. */ -static inline void cras_shm_set_callback_pending(struct cras_audio_shm *shm, - int pending) -{ - shm->header->callback_pending = !!pending; -} - -/* Returns non-zero if a callback is pending for this shm region. */ -static inline int cras_shm_callback_pending(const struct cras_audio_shm *shm) -{ - return shm->header->callback_pending; -} - -/* Sets the starting offset of a buffer */ -static inline void cras_shm_set_buffer_offset(struct cras_audio_shm *shm, - uint32_t buf_idx, uint32_t offset) -{ - shm->header->buffer_offset[buf_idx] = offset; -} - -/* Sets the used_size of the shm region. This is the maximum number of bytes - * that is exchanged each time a buffer is passed from client to server. - * - * Also sets the buffer_offsets to default values based on the used size. - */ -static inline void cras_shm_set_used_size(struct cras_audio_shm *shm, - unsigned used_size) -{ - uint32_t i; - - shm->config.used_size = used_size; - if (shm->header) { - shm->header->config.used_size = used_size; - - for (i = 0; i < CRAS_NUM_SHM_BUFFERS; i++) - cras_shm_set_buffer_offset(shm, i, i * used_size); - } -} - -/* Returns the used size of the shm region in bytes. */ -static inline unsigned cras_shm_used_size(const struct cras_audio_shm *shm) -{ - return shm->config.used_size; -} - -/* Returns the used size of the shm region in frames. */ -static inline unsigned cras_shm_used_frames(const struct cras_audio_shm *shm) -{ - return shm->config.used_size / shm->config.frame_bytes; -} - -/* Returns the size of the samples shm region. */ -static inline uint64_t cras_shm_samples_size(const struct cras_audio_shm *shm) -{ - return shm->samples_info.length; -} - -/* Gets the counter of over-runs. */ -static inline unsigned cras_shm_num_overruns(const struct cras_audio_shm *shm) -{ - return shm->header->num_overruns; -} - -/* Copy the config from the shm region to the local config. Used by clients - * when initially setting up the region. - */ -static inline void cras_shm_copy_shared_config(struct cras_audio_shm *shm) -{ - memcpy(&shm->config, &shm->header->config, sizeof(shm->config)); -} - -/* Open a read/write shared memory area with the given name. - * Args: - * name - Name of the shared-memory area. - * size - Size of the shared-memory area. - * Returns: - * >= 0 file descriptor value, or negative errno value on error. - */ -int cras_shm_open_rw(const char *name, size_t size); - -/* Reopen an existing shared memory area read-only. - * Args: - * name - Name of the shared-memory area. - * fd - Existing file descriptor. - * Returns: - * >= 0 new file descriptor value, or negative errno value on error. - */ -int cras_shm_reopen_ro(const char *name, int fd); - -/* Close and delete a shared memory area. - * Args: - * name - Name of the shared-memory area. - * fd - Existing file descriptor. - * Returns: - * >= 0 new file descriptor value, or negative errno value on error. - */ -void cras_shm_close_unlink(const char *name, int fd); - -/* - * Configure shared memory for the system state. - * Args: - * name - Name of the shared-memory area. - * mmap_size - Amount of shared memor to map. - * rw_fd_out - Filled with the RW fd for the shm region. - * ro_fd_out - Filled with the RO fd for the shm region. - * Returns a pointer to the new shared memory region. Or NULL on error. - */ -void *cras_shm_setup(const char *name, size_t mmap_size, int *rw_fd_out, - int *ro_fd_out); - -#ifdef CRAS_SELINUX -/* - * Wrapper around selinux_restorecon(). This is helpful in unit tests because - * we can mock out the selinux_restorecon() behaviour there. That is required - * because selinux_restorecon() would fail in the unit tests, since there - * is no file_contexts file. - * Args: - * pathname - Name of the file on which to run restorecon - * Returns 0 on success, otherwise -1 and errno is set appropriately. - */ -int cras_selinux_restorecon(const char *pathname); -#endif - -#endif /* CRAS_SHM_H_ */ |