cras/src/common/cras_shm.c - platform/external/adhd - Git at Google

 /* Copyright 2016 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.
  */

 #include <sys/cdefs.h>
 #include <sys/mman.h>
 #ifdef __BIONIC__
 #include <cutils/ashmem.h>
 #else
 #include <sys/shm.h>
 #endif
 #include <errno.h>
 #include <syslog.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>

 #include "cras_shm.h"

 int cras_shm_info_init(const char *stream_name, uint32_t length,
 		       struct cras_shm_info *info_out)
 {
 	struct cras_shm_info info;

 	if (!info_out)
 		return -EINVAL;

 	strncpy(info.name, stream_name, sizeof(info.name) - 1);
 	info.name[sizeof(info.name) - 1] = '\0';
 	info.length = length;
 	info.fd = cras_shm_open_rw(info.name, info.length);
 	if (info.fd < 0)
 		return info.fd;

 	*info_out = info;

 	return 0;
 }

 int cras_shm_info_init_with_fd(int fd, size_t length,
 			       struct cras_shm_info *info_out)
 {
 	struct cras_shm_info info;

 	if (!info_out)
 		return -EINVAL;

 	info.name[0] = '\0';
 	info.length = length;
 	info.fd = dup(fd);
 	if (info.fd < 0)
 		return info.fd;

 	*info_out = info;

 	return 0;
 }

 /* Move the resources from the cras_shm_info 'from' into the cras_shm_info 'to'.
  * The owner of 'to' will be responsible for cleaning up those resources with
  * cras_shm_info_cleanup.
  */
 static int cras_shm_info_move(struct cras_shm_info *from,
 			      struct cras_shm_info *to)
 {
 	if (!from || !to)
 		return -EINVAL;

 	*to = *from;
 	from->fd = -1;
 	from->name[0] = '\0';
 	return 0;
 }

 void cras_shm_info_cleanup(struct cras_shm_info *info)
 {
 	if (!info)
 		return;

 	if (info->name[0] != '\0')
 		cras_shm_close_unlink(info->name, info->fd);
 	else
 		close(info->fd);

 	info->fd = -1;
 	info->name[0] = '\0';
 }

 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)
 {
 	struct cras_audio_shm *shm;
 	int ret;

 	if (!header_info || !samples_info || !shm_out) {
 		ret = -EINVAL;
 		goto cleanup_info;
 	}

 	if (samples_prot != PROT_READ && samples_prot != PROT_WRITE) {
 		ret = -EINVAL;
 		syslog(LOG_ERR,
 		       "cras_shm: samples must be mapped read or write only");
 		goto cleanup_info;
 	}

 	shm = calloc(1, sizeof(*shm));
 	if (!shm) {
 		ret = -ENOMEM;
 		goto cleanup_info;
 	}

 	/* Move the cras_shm_info params into the new cras_audio_shm object.
 	 * The parameters are cleared, and the owner of cras_audio_shm is now
 	 * responsible for closing the fds and unlinking any associated shm
 	 * files using cras_audio_shm_destroy.
 	 */
 	ret = cras_shm_info_move(header_info, &shm->header_info);
 	if (ret)
 		goto free_shm;

 	ret = cras_shm_info_move(samples_info, &shm->samples_info);
 	if (ret)
 		goto free_shm;

 	shm->header =
 		mmap(NULL, shm->header_info.length, PROT_READ | PROT_WRITE,
 		     MAP_SHARED, shm->header_info.fd, 0);
 	if (shm->header == (struct cras_audio_shm_header *)-1) {
 		ret = -errno;
 		syslog(LOG_ERR, "cras_shm: mmap failed to map shm for header.");
 		goto free_shm;
 	}

 	shm->samples = mmap(NULL, shm->samples_info.length, samples_prot,
 			    MAP_SHARED, shm->samples_info.fd, 0);
 	if (shm->samples == (uint8_t *)-1) {
 		ret = -errno;
 		syslog(LOG_ERR,
 		       "cras_shm: mmap failed to map shm for samples.");
 		goto free_shm;
 	}

 	cras_shm_set_volume_scaler(shm, 1.0);

 	*shm_out = shm;
 	return 0;

 free_shm:
 	cras_audio_shm_destroy(shm);
 cleanup_info:
 	cras_shm_info_cleanup(samples_info);
 	cras_shm_info_cleanup(header_info);
 	return ret;
 }

 void cras_audio_shm_destroy(struct cras_audio_shm *shm)
 {
 	if (!shm)
 		return;

 	if (shm->samples != NULL && shm->samples != (uint8_t *)-1)
 		munmap(shm->samples, shm->samples_info.length);
 	cras_shm_info_cleanup(&shm->samples_info);
 	if (shm->header != NULL &&
 	    shm->header != (struct cras_audio_shm_header *)-1)
 		munmap(shm->header, shm->header_info.length);
 	cras_shm_info_cleanup(&shm->header_info);
 	free(shm);
 }

 /* Set the correct SELinux label for SHM fds. */
 static void cras_shm_restorecon(int fd)
 {
 #ifdef CRAS_SELINUX
 	char fd_proc_path[64];

 	if (snprintf(fd_proc_path, sizeof(fd_proc_path), "/proc/self/fd/%d",
 		     fd) < 0) {
 		syslog(LOG_WARNING,
 		       "Couldn't construct proc symlink path of fd: %d", fd);
 		return;
 	}

 	/* Get the actual file-path for this fd. */
 	char *path = realpath(fd_proc_path, NULL);
 	if (path == NULL) {
 		syslog(LOG_WARNING, "Couldn't run realpath() for %s: %s",
 		       fd_proc_path, strerror(errno));
 		return;
 	}

 	if (cras_selinux_restorecon(path) < 0) {
 		syslog(LOG_WARNING, "Restorecon on %s failed: %s", fd_proc_path,
 		       strerror(errno));
 	}

 	free(path);
 #endif
 }

 #ifdef __BIONIC__

 int cras_shm_open_rw(const char *name, size_t size)
 {
 	int fd;

 	/* Eliminate the / in the shm_name. */
 	if (name[0] == '/')
 		name++;
 	fd = ashmem_create_region(name, size);
 	if (fd < 0) {
 		fd = -errno;
 		syslog(LOG_ERR, "failed to ashmem_create_region %s: %s\n", name,
 		       strerror(-fd));
 	}
 	return fd;
 }

 int cras_shm_reopen_ro(const char *name, int fd)
 {
 	/* After mmaping the ashmem read/write, change it's protection
 	   bits to disallow further write access. */
 	if (ashmem_set_prot_region(fd, PROT_READ) != 0) {
 		fd = -errno;
 		syslog(LOG_ERR, "failed to ashmem_set_prot_region %s: %s\n",
 		       name, strerror(-fd));
 	}
 	return fd;
 }

 void cras_shm_close_unlink(const char *name, int fd)
 {
 	close(fd);
 }

 #else

 int cras_shm_open_rw(const char *name, size_t size)
 {
 	int fd;
 	int rc;

 	fd = shm_open(name, O_CREAT | O_EXCL | O_RDWR, 0600);
 	if (fd < 0) {
 		fd = -errno;
 		syslog(LOG_ERR, "failed to shm_open %s: %s\n", name,
 		       strerror(-fd));
 		return fd;
 	}
 	rc = posix_fallocate(fd, 0, size);
 	if (rc) {
 		rc = -errno;
 		syslog(LOG_ERR, "failed to set size of shm %s: %s\n", name,
 		       strerror(-rc));
 		return rc;
 	}

 	cras_shm_restorecon(fd);

 	return fd;
 }

 int cras_shm_reopen_ro(const char *name, int fd)
 {
 	/* Open a read-only copy to dup and pass to clients. */
 	fd = shm_open(name, O_RDONLY, 0);
 	if (fd < 0) {
 		fd = -errno;
 		syslog(LOG_ERR,
 		       "Failed to re-open shared memory '%s' read-only: %s",
 		       name, strerror(-fd));
 	}
 	return fd;
 }

 void cras_shm_close_unlink(const char *name, int fd)
 {
 	shm_unlink(name);
 	close(fd);
 }

 #endif

 void *cras_shm_setup(const char *name, size_t mmap_size, int *rw_fd_out,
 		     int *ro_fd_out)
 {
 	int rw_shm_fd = cras_shm_open_rw(name, mmap_size);
 	if (rw_shm_fd < 0)
 		return NULL;

 	/* mmap shm. */
 	void *exp_state = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
 			       MAP_SHARED, rw_shm_fd, 0);
 	if (exp_state == (void *)-1)
 		return NULL;

 	/* Open a read-only copy to dup and pass to clients. */
 	int ro_shm_fd = cras_shm_reopen_ro(name, rw_shm_fd);
 	if (ro_shm_fd < 0)
 		return NULL;

 	*rw_fd_out = rw_shm_fd;
 	*ro_fd_out = ro_shm_fd;

 	return exp_state;
 }
	/* Copyright 2016 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.
	*/

	#include <sys/cdefs.h>
	#include <sys/mman.h>
	#ifdef __BIONIC__
	#include <cutils/ashmem.h>
	#else
	#include <sys/shm.h>
	#endif
	#include <errno.h>
	#include <syslog.h>
	#include <stdio.h>
	#include <string.h>
	#include <unistd.h>

	#include "cras_shm.h"

	int cras_shm_info_init(const char *stream_name, uint32_t length,
	struct cras_shm_info *info_out)
	{
	struct cras_shm_info info;

	if (!info_out)
	return -EINVAL;

	strncpy(info.name, stream_name, sizeof(info.name) - 1);
	info.name[sizeof(info.name) - 1] = '\0';
	info.length = length;
	info.fd = cras_shm_open_rw(info.name, info.length);
	if (info.fd < 0)
	return info.fd;

	*info_out = info;

	return 0;
	}

	int cras_shm_info_init_with_fd(int fd, size_t length,
	struct cras_shm_info *info_out)
	{
	struct cras_shm_info info;

	if (!info_out)
	return -EINVAL;

	info.name[0] = '\0';
	info.length = length;
	info.fd = dup(fd);
	if (info.fd < 0)
	return info.fd;

	*info_out = info;

	return 0;
	}

	/* Move the resources from the cras_shm_info 'from' into the cras_shm_info 'to'.
	* The owner of 'to' will be responsible for cleaning up those resources with
	* cras_shm_info_cleanup.
	*/
	static int cras_shm_info_move(struct cras_shm_info *from,
	struct cras_shm_info *to)
	{
	if (!from \|\| !to)
	return -EINVAL;

	to = from;
	from->fd = -1;
	from->name[0] = '\0';
	return 0;
	}

	void cras_shm_info_cleanup(struct cras_shm_info *info)
	{
	if (!info)
	return;

	if (info->name[0] != '\0')
	cras_shm_close_unlink(info->name, info->fd);
	else
	close(info->fd);

	info->fd = -1;
	info->name[0] = '\0';
	}

	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)
	{
	struct cras_audio_shm *shm;
	int ret;

	if (!header_info \|\| !samples_info \|\| !shm_out) {
	ret = -EINVAL;
	goto cleanup_info;
	}

	if (samples_prot != PROT_READ && samples_prot != PROT_WRITE) {
	ret = -EINVAL;
	syslog(LOG_ERR,
	"cras_shm: samples must be mapped read or write only");
	goto cleanup_info;
	}

	shm = calloc(1, sizeof(*shm));
	if (!shm) {
	ret = -ENOMEM;
	goto cleanup_info;
	}

	/* Move the cras_shm_info params into the new cras_audio_shm object.
	* The parameters are cleared, and the owner of cras_audio_shm is now
	* responsible for closing the fds and unlinking any associated shm
	* files using cras_audio_shm_destroy.
	*/
	ret = cras_shm_info_move(header_info, &shm->header_info);
	if (ret)
	goto free_shm;

	ret = cras_shm_info_move(samples_info, &shm->samples_info);
	if (ret)
	goto free_shm;

	shm->header =
	mmap(NULL, shm->header_info.length, PROT_READ \| PROT_WRITE,
	MAP_SHARED, shm->header_info.fd, 0);
	if (shm->header == (struct cras_audio_shm_header *)-1) {
	ret = -errno;
	syslog(LOG_ERR, "cras_shm: mmap failed to map shm for header.");
	goto free_shm;
	}

	shm->samples = mmap(NULL, shm->samples_info.length, samples_prot,
	MAP_SHARED, shm->samples_info.fd, 0);
	if (shm->samples == (uint8_t *)-1) {
	ret = -errno;
	syslog(LOG_ERR,
	"cras_shm: mmap failed to map shm for samples.");
	goto free_shm;
	}

	cras_shm_set_volume_scaler(shm, 1.0);

	*shm_out = shm;
	return 0;

	free_shm:
	cras_audio_shm_destroy(shm);
	cleanup_info:
	cras_shm_info_cleanup(samples_info);
	cras_shm_info_cleanup(header_info);
	return ret;
	}

	void cras_audio_shm_destroy(struct cras_audio_shm *shm)
	{
	if (!shm)
	return;

	if (shm->samples != NULL && shm->samples != (uint8_t *)-1)
	munmap(shm->samples, shm->samples_info.length);
	cras_shm_info_cleanup(&shm->samples_info);
	if (shm->header != NULL &&
	shm->header != (struct cras_audio_shm_header *)-1)
	munmap(shm->header, shm->header_info.length);
	cras_shm_info_cleanup(&shm->header_info);
	free(shm);
	}

	/* Set the correct SELinux label for SHM fds. */
	static void cras_shm_restorecon(int fd)
	{
	#ifdef CRAS_SELINUX
	char fd_proc_path[64];

	if (snprintf(fd_proc_path, sizeof(fd_proc_path), "/proc/self/fd/%d",
	fd) < 0) {
	syslog(LOG_WARNING,
	"Couldn't construct proc symlink path of fd: %d", fd);
	return;
	}

	/* Get the actual file-path for this fd. */
	char *path = realpath(fd_proc_path, NULL);
	if (path == NULL) {
	syslog(LOG_WARNING, "Couldn't run realpath() for %s: %s",
	fd_proc_path, strerror(errno));
	return;
	}

	if (cras_selinux_restorecon(path) < 0) {
	syslog(LOG_WARNING, "Restorecon on %s failed: %s", fd_proc_path,
	strerror(errno));
	}

	free(path);
	#endif
	}

	#ifdef __BIONIC__

	int cras_shm_open_rw(const char *name, size_t size)
	{
	int fd;

	/* Eliminate the / in the shm_name. */
	if (name[0] == '/')
	name++;
	fd = ashmem_create_region(name, size);
	if (fd < 0) {
	fd = -errno;
	syslog(LOG_ERR, "failed to ashmem_create_region %s: %s\n", name,
	strerror(-fd));
	}
	return fd;
	}

	int cras_shm_reopen_ro(const char *name, int fd)
	{
	/* After mmaping the ashmem read/write, change it's protection
	bits to disallow further write access. */
	if (ashmem_set_prot_region(fd, PROT_READ) != 0) {
	fd = -errno;
	syslog(LOG_ERR, "failed to ashmem_set_prot_region %s: %s\n",
	name, strerror(-fd));
	}
	return fd;
	}

	void cras_shm_close_unlink(const char *name, int fd)
	{
	close(fd);
	}

	#else

	int cras_shm_open_rw(const char *name, size_t size)
	{
	int fd;
	int rc;

	fd = shm_open(name, O_CREAT \| O_EXCL \| O_RDWR, 0600);
	if (fd < 0) {
	fd = -errno;
	syslog(LOG_ERR, "failed to shm_open %s: %s\n", name,
	strerror(-fd));
	return fd;
	}
	rc = posix_fallocate(fd, 0, size);
	if (rc) {
	rc = -errno;
	syslog(LOG_ERR, "failed to set size of shm %s: %s\n", name,
	strerror(-rc));
	return rc;
	}

	cras_shm_restorecon(fd);

	return fd;
	}

	int cras_shm_reopen_ro(const char *name, int fd)
	{
	/* Open a read-only copy to dup and pass to clients. */
	fd = shm_open(name, O_RDONLY, 0);
	if (fd < 0) {
	fd = -errno;
	syslog(LOG_ERR,
	"Failed to re-open shared memory '%s' read-only: %s",
	name, strerror(-fd));
	}
	return fd;
	}

	void cras_shm_close_unlink(const char *name, int fd)
	{
	shm_unlink(name);
	close(fd);
	}

	#endif

	void cras_shm_setup(const char name, size_t mmap_size, int *rw_fd_out,
	int *ro_fd_out)
	{
	int rw_shm_fd = cras_shm_open_rw(name, mmap_size);
	if (rw_shm_fd < 0)
	return NULL;

	/* mmap shm. */
	void *exp_state = mmap(NULL, mmap_size, PROT_READ \| PROT_WRITE,
	MAP_SHARED, rw_shm_fd, 0);
	if (exp_state == (void *)-1)
	return NULL;

	/* Open a read-only copy to dup and pass to clients. */
	int ro_shm_fd = cras_shm_reopen_ro(name, rw_shm_fd);
	if (ro_shm_fd < 0)
	return NULL;

	*rw_fd_out = rw_shm_fd;
	*ro_fd_out = ro_shm_fd;

	return exp_state;
	}