linux/sound/core/oss/pcm_plugin.h
Gustavo A. R. Silva 9ad06ebb9a ALSA: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200507192223.GA16335@embeddedor
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-05-07 22:30:36 +02:00

169 lines
6.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef __PCM_PLUGIN_H
#define __PCM_PLUGIN_H
/*
* Digital Audio (Plugin interface) abstract layer
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
*/
#ifdef CONFIG_SND_PCM_OSS_PLUGINS
#define snd_pcm_plug_stream(plug) ((plug)->stream)
enum snd_pcm_plugin_action {
INIT = 0,
PREPARE = 1,
};
struct snd_pcm_channel_area {
void *addr; /* base address of channel samples */
unsigned int first; /* offset to first sample in bits */
unsigned int step; /* samples distance in bits */
};
struct snd_pcm_plugin_channel {
void *aptr; /* pointer to the allocated area */
struct snd_pcm_channel_area area;
snd_pcm_uframes_t frames; /* allocated frames */
unsigned int enabled:1; /* channel need to be processed */
unsigned int wanted:1; /* channel is wanted */
};
struct snd_pcm_plugin_format {
snd_pcm_format_t format;
unsigned int rate;
unsigned int channels;
};
struct snd_pcm_plugin {
const char *name; /* plug-in name */
int stream;
struct snd_pcm_plugin_format src_format; /* source format */
struct snd_pcm_plugin_format dst_format; /* destination format */
int src_width; /* sample width in bits */
int dst_width; /* sample width in bits */
snd_pcm_access_t access;
snd_pcm_sframes_t (*src_frames)(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t dst_frames);
snd_pcm_sframes_t (*dst_frames)(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t src_frames);
snd_pcm_sframes_t (*client_channels)(struct snd_pcm_plugin *plugin,
snd_pcm_uframes_t frames,
struct snd_pcm_plugin_channel **channels);
snd_pcm_sframes_t (*transfer)(struct snd_pcm_plugin *plugin,
const struct snd_pcm_plugin_channel *src_channels,
struct snd_pcm_plugin_channel *dst_channels,
snd_pcm_uframes_t frames);
int (*action)(struct snd_pcm_plugin *plugin,
enum snd_pcm_plugin_action action,
unsigned long data);
struct snd_pcm_plugin *prev;
struct snd_pcm_plugin *next;
struct snd_pcm_substream *plug;
void *private_data;
void (*private_free)(struct snd_pcm_plugin *plugin);
char *buf;
snd_pcm_uframes_t buf_frames;
struct snd_pcm_plugin_channel *buf_channels;
char extra_data[];
};
int snd_pcm_plugin_build(struct snd_pcm_substream *handle,
const char *name,
struct snd_pcm_plugin_format *src_format,
struct snd_pcm_plugin_format *dst_format,
size_t extra,
struct snd_pcm_plugin **ret);
int snd_pcm_plugin_free(struct snd_pcm_plugin *plugin);
int snd_pcm_plugin_clear(struct snd_pcm_plugin **first);
int snd_pcm_plug_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t frames);
snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *handle, snd_pcm_uframes_t drv_size);
snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *handle, snd_pcm_uframes_t clt_size);
#define FULL ROUTE_PLUGIN_RESOLUTION
#define HALF ROUTE_PLUGIN_RESOLUTION / 2
int snd_pcm_plugin_build_io(struct snd_pcm_substream *handle,
struct snd_pcm_hw_params *params,
struct snd_pcm_plugin **r_plugin);
int snd_pcm_plugin_build_linear(struct snd_pcm_substream *handle,
struct snd_pcm_plugin_format *src_format,
struct snd_pcm_plugin_format *dst_format,
struct snd_pcm_plugin **r_plugin);
int snd_pcm_plugin_build_mulaw(struct snd_pcm_substream *handle,
struct snd_pcm_plugin_format *src_format,
struct snd_pcm_plugin_format *dst_format,
struct snd_pcm_plugin **r_plugin);
int snd_pcm_plugin_build_rate(struct snd_pcm_substream *handle,
struct snd_pcm_plugin_format *src_format,
struct snd_pcm_plugin_format *dst_format,
struct snd_pcm_plugin **r_plugin);
int snd_pcm_plugin_build_route(struct snd_pcm_substream *handle,
struct snd_pcm_plugin_format *src_format,
struct snd_pcm_plugin_format *dst_format,
struct snd_pcm_plugin **r_plugin);
int snd_pcm_plugin_build_copy(struct snd_pcm_substream *handle,
struct snd_pcm_plugin_format *src_format,
struct snd_pcm_plugin_format *dst_format,
struct snd_pcm_plugin **r_plugin);
int snd_pcm_plug_format_plugins(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params,
struct snd_pcm_hw_params *slave_params);
snd_pcm_format_t snd_pcm_plug_slave_format(snd_pcm_format_t format,
const struct snd_mask *format_mask);
int snd_pcm_plugin_append(struct snd_pcm_plugin *plugin);
snd_pcm_sframes_t snd_pcm_plug_write_transfer(struct snd_pcm_substream *handle,
struct snd_pcm_plugin_channel *src_channels,
snd_pcm_uframes_t size);
snd_pcm_sframes_t snd_pcm_plug_read_transfer(struct snd_pcm_substream *handle,
struct snd_pcm_plugin_channel *dst_channels_final,
snd_pcm_uframes_t size);
snd_pcm_sframes_t snd_pcm_plug_client_channels_buf(struct snd_pcm_substream *handle,
char *buf, snd_pcm_uframes_t count,
struct snd_pcm_plugin_channel **channels);
snd_pcm_sframes_t snd_pcm_plugin_client_channels(struct snd_pcm_plugin *plugin,
snd_pcm_uframes_t frames,
struct snd_pcm_plugin_channel **channels);
int snd_pcm_area_silence(const struct snd_pcm_channel_area *dst_channel,
size_t dst_offset,
size_t samples, snd_pcm_format_t format);
int snd_pcm_area_copy(const struct snd_pcm_channel_area *src_channel,
size_t src_offset,
const struct snd_pcm_channel_area *dst_channel,
size_t dst_offset,
size_t samples, snd_pcm_format_t format);
void *snd_pcm_plug_buf_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t size);
void snd_pcm_plug_buf_unlock(struct snd_pcm_substream *plug, void *ptr);
snd_pcm_sframes_t snd_pcm_oss_write3(struct snd_pcm_substream *substream,
const char *ptr, snd_pcm_uframes_t size,
int in_kernel);
snd_pcm_sframes_t snd_pcm_oss_read3(struct snd_pcm_substream *substream,
char *ptr, snd_pcm_uframes_t size, int in_kernel);
snd_pcm_sframes_t snd_pcm_oss_writev3(struct snd_pcm_substream *substream,
void **bufs, snd_pcm_uframes_t frames);
snd_pcm_sframes_t snd_pcm_oss_readv3(struct snd_pcm_substream *substream,
void **bufs, snd_pcm_uframes_t frames);
#else
static inline snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *handle, snd_pcm_uframes_t drv_size) { return drv_size; }
static inline snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *handle, snd_pcm_uframes_t clt_size) { return clt_size; }
static inline int snd_pcm_plug_slave_format(int format, const struct snd_mask *format_mask) { return format; }
#endif
#ifdef PLUGIN_DEBUG
#define pdprintf(fmt, args...) printk(KERN_DEBUG "plugin: " fmt, ##args)
#else
#define pdprintf(fmt, args...)
#endif
#endif /* __PCM_PLUGIN_H */