[lttng-ust.git] / libringbuffer / shm.c

/*
 * libringbuffer/shm.c
 *
 * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "shm.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>	/* For mode constants */
#include <fcntl.h>	/* For O_* constants */
#include <assert.h>
#include <stdio.h>
#include <signal.h>
#include <dirent.h>
#include <lttng/align.h>
#include <helper.h>
#include <limits.h>
#include <helper.h>

/*
 * Ensure we have the required amount of space available by writing 0
 * into the entire buffer. Not doing so can trigger SIGBUS when going
 * beyond the available shm space.
 */
static
int zero_file(int fd, size_t len)
{
	ssize_t retlen;
	size_t written = 0;
	char *zeropage;
	long pagelen;
	int ret;

	pagelen = sysconf(_SC_PAGESIZE);
	if (pagelen < 0)
		return (int) pagelen;
	zeropage = calloc(pagelen, 1);
	if (!zeropage)
		return -ENOMEM;

	while (len > written) {
		do {
			retlen = write(fd, zeropage,
				min_t(size_t, pagelen, len - written));
		} while (retlen == -1UL && errno == EINTR);
		if (retlen < 0) {
			ret = (int) retlen;
			goto error;
		}
		written += retlen;
	}
	ret = 0;
error:
	free(zeropage);
	return ret;
}

struct shm_object_table *shm_object_table_create(size_t max_nb_obj)
{
	struct shm_object_table *table;

	table = zmalloc(sizeof(struct shm_object_table) +
			max_nb_obj * sizeof(table->objects[0]));
	if (!table)
		return NULL;
	table->size = max_nb_obj;
	return table;
}

static
struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table,
					   size_t memory_map_size)
{
	int shmfd, waitfd[2], ret, i, sigblocked = 0;
	struct shm_object *obj;
	char *memory_map;
	char tmp_name[NAME_MAX] = "/ust-shm-tmp-XXXXXX";
	sigset_t all_sigs, orig_sigs;

	if (table->allocated_len >= table->size)
		return NULL;
	obj = &table->objects[table->allocated_len];

	/* wait_fd: create pipe */
	ret = pipe(waitfd);
	if (ret < 0) {
		PERROR("pipe");
		goto error_pipe;
	}
	for (i = 0; i < 2; i++) {
		ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
		if (ret < 0) {
			PERROR("fcntl");
			goto error_fcntl;
		}
	}
	/* The write end of the pipe needs to be non-blocking */
	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	if (ret < 0) {
		PERROR("fcntl");
		goto error_fcntl;
	}
	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));

	/* shm_fd: create shm */

	/*
	 * Theoretically, we could leak a shm if the application crashes
	 * between open and unlink. Disable signals on this thread for
	 * increased safety against this scenario.
	 */
	sigfillset(&all_sigs);
	ret = pthread_sigmask(SIG_BLOCK, &all_sigs, &orig_sigs);
	if (ret == -1) {
		PERROR("pthread_sigmask");
		goto error_pthread_sigmask;
	}
	sigblocked = 1;

	/*
	 * Allocate shm, and immediately unlink its shm oject, keeping
	 * only the file descriptor as a reference to the object. If it
	 * already exists (caused by short race window during which the
	 * global object exists in a concurrent shm_open), simply retry.
	 * We specifically do _not_ use the / at the beginning of the
	 * pathname so that some OS implementations can keep it local to
	 * the process (POSIX leaves this implementation-defined).
	 */
	do {
		/*
		 * Using mktemp filename with O_CREAT | O_EXCL open
		 * flags.
		 */
		(void) mktemp(tmp_name);
		if (tmp_name[0] == '\0') {
			PERROR("mktemp");
			goto error_shm_open;
		}
		shmfd = shm_open(tmp_name,
				 O_CREAT | O_EXCL | O_RDWR, 0700);
	} while (shmfd < 0 && (errno == EEXIST || errno == EACCES));
	if (shmfd < 0) {
		PERROR("shm_open");
		goto error_shm_open;
	}
	ret = shm_unlink(tmp_name);
	if (ret < 0 && errno != ENOENT) {
		PERROR("shm_unlink");
		goto error_shm_release;
	}
	sigblocked = 0;
	ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL);
	if (ret == -1) {
		PERROR("pthread_sigmask");
		goto error_sigmask_release;
	}
	ret = zero_file(shmfd, memory_map_size);
	if (ret) {
		PERROR("zero_file");
		goto error_zero_file;
	}
	ret = ftruncate(shmfd, memory_map_size);
	if (ret) {
		PERROR("ftruncate");
		goto error_ftruncate;
	}
	obj->shm_fd = shmfd;

	/* memory_map: mmap */
	memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE,
			  MAP_SHARED, shmfd, 0);
	if (memory_map == MAP_FAILED) {
		PERROR("mmap");
		goto error_mmap;
	}
	obj->type = SHM_OBJECT_SHM;
	obj->memory_map = memory_map;
	obj->memory_map_size = memory_map_size;
	obj->allocated_len = 0;
	obj->index = table->allocated_len++;

	return obj;

error_mmap:
error_ftruncate:
error_shm_release:
error_zero_file:
error_sigmask_release:
	ret = close(shmfd);
	if (ret) {
		PERROR("close");
		assert(0);
	}
error_shm_open:
	if (sigblocked) {
		ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL);
		if (ret == -1) {
			PERROR("pthread_sigmask");
		}
	}
error_pthread_sigmask:
error_fcntl:
	for (i = 0; i < 2; i++) {
		ret = close(waitfd[i]);
		if (ret) {
			PERROR("close");
			assert(0);
		}
	}
error_pipe:
	return NULL;
}

static
struct shm_object *_shm_object_table_alloc_mem(struct shm_object_table *table,
					   size_t memory_map_size)
{
	struct shm_object *obj;
	void *memory_map;
	int waitfd[2], i, ret;

	if (table->allocated_len >= table->size)
		return NULL;
	obj = &table->objects[table->allocated_len];

	memory_map = zmalloc(memory_map_size);
	if (!memory_map)
		goto alloc_error;

	/* wait_fd: create pipe */
	ret = pipe(waitfd);
	if (ret < 0) {
		PERROR("pipe");
		goto error_pipe;
	}
	for (i = 0; i < 2; i++) {
		ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
		if (ret < 0) {
			PERROR("fcntl");
			goto error_fcntl;
		}
	}
	/* The write end of the pipe needs to be non-blocking */
	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	if (ret < 0) {
		PERROR("fcntl");
		goto error_fcntl;
	}
	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));

	/* no shm_fd */
	obj->shm_fd = -1;

	obj->type = SHM_OBJECT_MEM;
	obj->memory_map = memory_map;
	obj->memory_map_size = memory_map_size;
	obj->allocated_len = 0;
	obj->index = table->allocated_len++;

	return obj;

error_fcntl:
	for (i = 0; i < 2; i++) {
		ret = close(waitfd[i]);
		if (ret) {
			PERROR("close");
			assert(0);
		}
	}
error_pipe:
	free(memory_map);
alloc_error:
	return NULL;
}

struct shm_object *shm_object_table_alloc(struct shm_object_table *table,
			size_t memory_map_size,
			enum shm_object_type type)
{
	switch (type) {
	case SHM_OBJECT_SHM:
		return _shm_object_table_alloc_shm(table, memory_map_size);
	case SHM_OBJECT_MEM:
		return _shm_object_table_alloc_mem(table, memory_map_size);
	default:
		assert(0);
	}
	return NULL;
}

struct shm_object *shm_object_table_append_shm(struct shm_object_table *table,
			int shm_fd, int wakeup_fd, uint32_t stream_nr,
			size_t memory_map_size)
{
	struct shm_object *obj;
	char *memory_map;
	int ret;

	if (table->allocated_len >= table->size)
		return NULL;
	/* streams _must_ be received in sequential order, else fail. */
	if (stream_nr + 1 != table->allocated_len)
		return NULL;

	obj = &table->objects[table->allocated_len];

	/* wait_fd: set write end of the pipe. */
	obj->wait_fd[0] = -1;	/* read end is unset */
	obj->wait_fd[1] = wakeup_fd;
	obj->shm_fd = shm_fd;

	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	if (ret < 0) {
		PERROR("fcntl");
		goto error_fcntl;
	}
	/* The write end of the pipe needs to be non-blocking */
	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	if (ret < 0) {
		PERROR("fcntl");
		goto error_fcntl;
	}

	/* memory_map: mmap */
	memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE,
			  MAP_SHARED, shm_fd, 0);
	if (memory_map == MAP_FAILED) {
		PERROR("mmap");
		goto error_mmap;
	}
	obj->type = SHM_OBJECT_SHM;
	obj->memory_map = memory_map;
	obj->memory_map_size = memory_map_size;
	obj->allocated_len = memory_map_size;
	obj->index = table->allocated_len++;

	return obj;

error_fcntl:
error_mmap:
	return NULL;
}

/*
 * Passing ownership of mem to object.
 */
struct shm_object *shm_object_table_append_mem(struct shm_object_table *table,
			void *mem, size_t memory_map_size, int wakeup_fd)
{
	struct shm_object *obj;
	int ret;

	if (table->allocated_len >= table->size)
		return NULL;
	obj = &table->objects[table->allocated_len];

	obj->wait_fd[0] = -1;	/* read end is unset */
	obj->wait_fd[1] = wakeup_fd;
	obj->shm_fd = -1;

	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	if (ret < 0) {
		PERROR("fcntl");
		goto error_fcntl;
	}
	/* The write end of the pipe needs to be non-blocking */
	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	if (ret < 0) {
		PERROR("fcntl");
		goto error_fcntl;
	}

	obj->type = SHM_OBJECT_MEM;
	obj->memory_map = mem;
	obj->memory_map_size = memory_map_size;
	obj->allocated_len = memory_map_size;
	obj->index = table->allocated_len++;

	return obj;

error_fcntl:
	return NULL;
}

static
void shmp_object_destroy(struct shm_object *obj)
{
	switch (obj->type) {
	case SHM_OBJECT_SHM:
	{
		int ret, i;

		ret = munmap(obj->memory_map, obj->memory_map_size);
		if (ret) {
			PERROR("umnmap");
			assert(0);
		}
		ret = close(obj->shm_fd);
		if (ret) {
			PERROR("close");
			assert(0);
		}
		for (i = 0; i < 2; i++) {
			if (obj->wait_fd[i] < 0)
				continue;
			ret = close(obj->wait_fd[i]);
			if (ret) {
				PERROR("close");
				assert(0);
			}
		}
		break;
	}
	case SHM_OBJECT_MEM:
	{
		int ret, i;

		for (i = 0; i < 2; i++) {
			if (obj->wait_fd[i] < 0)
				continue;
			ret = close(obj->wait_fd[i]);
			if (ret) {
				PERROR("close");
				assert(0);
			}
		}
		free(obj->memory_map);
		break;
	}
	default:
		assert(0);
	}
}

void shm_object_table_destroy(struct shm_object_table *table)
{
	int i;

	for (i = 0; i < table->allocated_len; i++)
		shmp_object_destroy(&table->objects[i]);
	free(table);
}

/*
 * zalloc_shm - allocate memory within a shm object.
 *
 * Shared memory is already zeroed by shmget.
 * *NOT* multithread-safe (should be protected by mutex).
 * Returns a -1, -1 tuple on error.
 */
struct shm_ref zalloc_shm(struct shm_object *obj, size_t len)
{
	struct shm_ref ref;
	struct shm_ref shm_ref_error = { -1, -1 };

	if (obj->memory_map_size - obj->allocated_len < len)
		return shm_ref_error;
	ref.index = obj->index;
	ref.offset =  obj->allocated_len;
	obj->allocated_len += len;
	return ref;
}

void align_shm(struct shm_object *obj, size_t align)
{
	size_t offset_len = offset_align(obj->allocated_len, align);
	obj->allocated_len += offset_len;
}
Commit	Line	Data
1d498196 MD	1	/*
	2	* libringbuffer/shm.c
	3	*
e92f3e28	4	* Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
1d498196	5	*
e92f3e28 MD	6	* This library is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU Lesser General Public
	8	* License as published by the Free Software Foundation; only
	9	* version 2.1 of the License.
	10	*
	11	* This library is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* Lesser General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU Lesser General Public
	17	* License along with this library; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
1d498196 MD	19	*/
	20
	21	#include "shm.h"
	22	#include <unistd.h>
	23	#include <fcntl.h>
	24	#include <sys/mman.h>
	25	#include <sys/stat.h> /* For mode constants */
	26	#include <fcntl.h> /* For O_* constants */
	27	#include <assert.h>
8da6cd6d MD	28	#include <stdio.h>
	29	#include <signal.h>
	30	#include <dirent.h>
4318ae1b	31	#include <lttng/align.h>
35897f8b	32	#include <helper.h>
96e80018	33	#include <limits.h>
3a81f31d MD	34	#include <helper.h>
	35
	36	/*
	37	* Ensure we have the required amount of space available by writing 0
	38	* into the entire buffer. Not doing so can trigger SIGBUS when going
	39	* beyond the available shm space.
	40	*/
	41	static
	42	int zero_file(int fd, size_t len)
	43	{
	44	ssize_t retlen;
	45	size_t written = 0;
	46	char *zeropage;
	47	long pagelen;
	48	int ret;
	49
	50	pagelen = sysconf(_SC_PAGESIZE);
	51	if (pagelen < 0)
	52	return (int) pagelen;
	53	zeropage = calloc(pagelen, 1);
	54	if (!zeropage)
	55	return -ENOMEM;
	56
	57	while (len > written) {
	58	do {
	59	retlen = write(fd, zeropage,
	60	min_t(size_t, pagelen, len - written));
	61	} while (retlen == -1UL && errno == EINTR);
	62	if (retlen < 0) {
	63	ret = (int) retlen;
	64	goto error;
	65	}
	66	written += retlen;
	67	}
	68	ret = 0;
	69	error:
	70	free(zeropage);
	71	return ret;
	72	}
1d498196 MD	73
	74	struct shm_object_table *shm_object_table_create(size_t max_nb_obj)
	75	{
	76	struct shm_object_table *table;
	77
	78	table = zmalloc(sizeof(struct shm_object_table) +
	79	max_nb_obj * sizeof(table->objects[0]));
911360f6 MD	80	if (!table)
911360f6 MD	81	return NULL;
1d498196 MD	82	table->size = max_nb_obj;
	83	return table;
	84	}
	85
74d81a6c MD	86	static
74d81a6c MD	87	struct shm_object _shm_object_table_alloc_shm(struct shm_object_table table,
1d498196 MD	88	size_t memory_map_size)
1d498196 MD	89	{
5a61337d	90	int shmfd, waitfd[2], ret, i, sigblocked = 0;
1d498196 MD	91	struct shm_object *obj;
1d498196 MD	92	char *memory_map;
dda4784f	93	char tmp_name[NAME_MAX] = "/ust-shm-tmp-XXXXXX";
8da6cd6d	94	sigset_t all_sigs, orig_sigs;
1d498196 MD	95
	96	if (table->allocated_len >= table->size)
	97	return NULL;
7a9c21bd	98	obj = &table->objects[table->allocated_len];
1d498196 MD	99
	100	/* wait_fd: create pipe */
	101	ret = pipe(waitfd);
	102	if (ret < 0) {
	103	PERROR("pipe");
	104	goto error_pipe;
	105	}
	106	for (i = 0; i < 2; i++) {
	107	ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
	108	if (ret < 0) {
	109	PERROR("fcntl");
	110	goto error_fcntl;
	111	}
	112	}
5d61a504 MD	113	/* The write end of the pipe needs to be non-blocking */
	114	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	115	if (ret < 0) {
	116	PERROR("fcntl");
	117	goto error_fcntl;
	118	}
7a9c21bd	119	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
1d498196 MD	120
	121	/* shm_fd: create shm */
	122
8da6cd6d MD	123	/*
	124	* Theoretically, we could leak a shm if the application crashes
	125	* between open and unlink. Disable signals on this thread for
	126	* increased safety against this scenario.
	127	*/
	128	sigfillset(&all_sigs);
	129	ret = pthread_sigmask(SIG_BLOCK, &all_sigs, &orig_sigs);
	130	if (ret == -1) {
	131	PERROR("pthread_sigmask");
	132	goto error_pthread_sigmask;
	133	}
5a61337d	134	sigblocked = 1;
8da6cd6d	135
1d498196 MD	136	/*
	137	* Allocate shm, and immediately unlink its shm oject, keeping
	138	* only the file descriptor as a reference to the object. If it
	139	* already exists (caused by short race window during which the
	140	* global object exists in a concurrent shm_open), simply retry.
	141	* We specifically do _not_ use the / at the beginning of the
	142	* pathname so that some OS implementations can keep it local to
	143	* the process (POSIX leaves this implementation-defined).
	144	*/
	145	do {
8da6cd6d MD	146	/*
	147	* Using mktemp filename with O_CREAT \| O_EXCL open
	148	* flags.
	149	*/
af21f781	150	(void) mktemp(tmp_name);
8da6cd6d MD	151	if (tmp_name[0] == '\0') {
	152	PERROR("mktemp");
	153	goto error_shm_open;
a8803897	154	}
8da6cd6d	155	shmfd = shm_open(tmp_name,
1d498196	156	O_CREAT \| O_EXCL \| O_RDWR, 0700);
8da6cd6d	157	} while (shmfd < 0 && (errno == EEXIST \|\| errno == EACCES));
1d498196 MD	158	if (shmfd < 0) {
	159	PERROR("shm_open");
	160	goto error_shm_open;
	161	}
8da6cd6d	162	ret = shm_unlink(tmp_name);
a8803897 MD	163	if (ret < 0 && errno != ENOENT) {
	164	PERROR("shm_unlink");
	165	goto error_shm_release;
	166	}
5a61337d	167	sigblocked = 0;
8da6cd6d MD	168	ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL);
	169	if (ret == -1) {
	170	PERROR("pthread_sigmask");
5a61337d	171	goto error_sigmask_release;
8da6cd6d	172	}
3a81f31d MD	173	ret = zero_file(shmfd, memory_map_size);
	174	if (ret) {
	175	PERROR("zero_file");
	176	goto error_zero_file;
	177	}
1d498196 MD	178	ret = ftruncate(shmfd, memory_map_size);
	179	if (ret) {
	180	PERROR("ftruncate");
	181	goto error_ftruncate;
	182	}
	183	obj->shm_fd = shmfd;
	184
	185	/* memory_map: mmap */
	186	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	187	MAP_SHARED, shmfd, 0);
	188	if (memory_map == MAP_FAILED) {
	189	PERROR("mmap");
	190	goto error_mmap;
	191	}
74d81a6c	192	obj->type = SHM_OBJECT_SHM;
1d498196 MD	193	obj->memory_map = memory_map;
	194	obj->memory_map_size = memory_map_size;
	195	obj->allocated_len = 0;
dc613eb9	196	obj->index = table->allocated_len++;
7a9c21bd	197
1d498196 MD	198	return obj;
	199
	200	error_mmap:
	201	error_ftruncate:
a8803897	202	error_shm_release:
3a81f31d	203	error_zero_file:
5a61337d	204	error_sigmask_release:
1d498196 MD	205	ret = close(shmfd);
	206	if (ret) {
	207	PERROR("close");
	208	assert(0);
	209	}
	210	error_shm_open:
5a61337d MD	211	if (sigblocked) {
	212	ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL);
	213	if (ret == -1) {
	214	PERROR("pthread_sigmask");
	215	}
	216	}
8da6cd6d	217	error_pthread_sigmask:
1d498196 MD	218	error_fcntl:
	219	for (i = 0; i < 2; i++) {
	220	ret = close(waitfd[i]);
	221	if (ret) {
	222	PERROR("close");
	223	assert(0);
	224	}
	225	}
	226	error_pipe:
1d498196	227	return NULL;
1d498196 MD	228	}
1d498196 MD	229
74d81a6c MD	230	static
	231	struct shm_object _shm_object_table_alloc_mem(struct shm_object_table table,
	232	size_t memory_map_size)
	233	{
	234	struct shm_object *obj;
	235	void *memory_map;
ff0f5728	236	int waitfd[2], i, ret;
74d81a6c MD	237
	238	if (table->allocated_len >= table->size)
	239	return NULL;
	240	obj = &table->objects[table->allocated_len];
	241
	242	memory_map = zmalloc(memory_map_size);
	243	if (!memory_map)
	244	goto alloc_error;
	245
ff0f5728 MD	246	/* wait_fd: create pipe */
	247	ret = pipe(waitfd);
	248	if (ret < 0) {
	249	PERROR("pipe");
	250	goto error_pipe;
	251	}
	252	for (i = 0; i < 2; i++) {
	253	ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
	254	if (ret < 0) {
	255	PERROR("fcntl");
	256	goto error_fcntl;
	257	}
	258	}
	259	/* The write end of the pipe needs to be non-blocking */
	260	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	261	if (ret < 0) {
	262	PERROR("fcntl");
	263	goto error_fcntl;
	264	}
	265	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
	266
	267	/* no shm_fd */
74d81a6c MD	268	obj->shm_fd = -1;
	269
	270	obj->type = SHM_OBJECT_MEM;
	271	obj->memory_map = memory_map;
	272	obj->memory_map_size = memory_map_size;
	273	obj->allocated_len = 0;
	274	obj->index = table->allocated_len++;
	275
	276	return obj;
	277
ff0f5728 MD	278	error_fcntl:
	279	for (i = 0; i < 2; i++) {
	280	ret = close(waitfd[i]);
	281	if (ret) {
	282	PERROR("close");
	283	assert(0);
	284	}
	285	}
	286	error_pipe:
	287	free(memory_map);
74d81a6c MD	288	alloc_error:
	289	return NULL;
	290	}
	291
	292	struct shm_object shm_object_table_alloc(struct shm_object_table table,
	293	size_t memory_map_size,
	294	enum shm_object_type type)
	295	{
	296	switch (type) {
	297	case SHM_OBJECT_SHM:
	298	return _shm_object_table_alloc_shm(table, memory_map_size);
	299	case SHM_OBJECT_MEM:
	300	return _shm_object_table_alloc_mem(table, memory_map_size);
	301	default:
	302	assert(0);
	303	}
	304	return NULL;
	305	}
	306
	307	struct shm_object shm_object_table_append_shm(struct shm_object_table table,
	308	int shm_fd, int wakeup_fd, uint32_t stream_nr,
	309	size_t memory_map_size)
193183fb MD	310	{
	311	struct shm_object *obj;
	312	char *memory_map;
74d81a6c	313	int ret;
193183fb MD	314
	315	if (table->allocated_len >= table->size)
	316	return NULL;
74d81a6c MD	317	/* streams _must_ be received in sequential order, else fail. */
	318	if (stream_nr + 1 != table->allocated_len)
	319	return NULL;
	320
193183fb MD	321	obj = &table->objects[table->allocated_len];
193183fb MD	322
74d81a6c MD	323	/* wait_fd: set write end of the pipe. */
	324	obj->wait_fd[0] = -1; /* read end is unset */
	325	obj->wait_fd[1] = wakeup_fd;
193183fb MD	326	obj->shm_fd = shm_fd;
193183fb MD	327
74d81a6c MD	328	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	329	if (ret < 0) {
	330	PERROR("fcntl");
	331	goto error_fcntl;
	332	}
	333	/* The write end of the pipe needs to be non-blocking */
	334	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	335	if (ret < 0) {
	336	PERROR("fcntl");
	337	goto error_fcntl;
	338	}
	339
193183fb MD	340	/* memory_map: mmap */
	341	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	342	MAP_SHARED, shm_fd, 0);
	343	if (memory_map == MAP_FAILED) {
	344	PERROR("mmap");
	345	goto error_mmap;
	346	}
74d81a6c	347	obj->type = SHM_OBJECT_SHM;
193183fb MD	348	obj->memory_map = memory_map;
	349	obj->memory_map_size = memory_map_size;
	350	obj->allocated_len = memory_map_size;
	351	obj->index = table->allocated_len++;
	352
	353	return obj;
	354
74d81a6c	355	error_fcntl:
193183fb MD	356	error_mmap:
	357	return NULL;
	358	}
	359
74d81a6c MD	360	/*
	361	* Passing ownership of mem to object.
	362	*/
	363	struct shm_object shm_object_table_append_mem(struct shm_object_table table,
ff0f5728	364	void *mem, size_t memory_map_size, int wakeup_fd)
74d81a6c MD	365	{
74d81a6c MD	366	struct shm_object *obj;
ff0f5728	367	int ret;
74d81a6c MD	368
	369	if (table->allocated_len >= table->size)
	370	return NULL;
	371	obj = &table->objects[table->allocated_len];
	372
ff0f5728 MD	373	obj->wait_fd[0] = -1; /* read end is unset */
ff0f5728 MD	374	obj->wait_fd[1] = wakeup_fd;
74d81a6c MD	375	obj->shm_fd = -1;
74d81a6c MD	376
ff0f5728 MD	377	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	378	if (ret < 0) {
	379	PERROR("fcntl");
	380	goto error_fcntl;
	381	}
	382	/* The write end of the pipe needs to be non-blocking */
	383	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	384	if (ret < 0) {
	385	PERROR("fcntl");
	386	goto error_fcntl;
	387	}
	388
74d81a6c MD	389	obj->type = SHM_OBJECT_MEM;
	390	obj->memory_map = mem;
	391	obj->memory_map_size = memory_map_size;
	392	obj->allocated_len = memory_map_size;
	393	obj->index = table->allocated_len++;
	394
	395	return obj;
ff0f5728 MD	396
	397	error_fcntl:
	398	return NULL;
74d81a6c MD	399	}
74d81a6c MD	400
1d498196 MD	401	static
	402	void shmp_object_destroy(struct shm_object *obj)
	403	{
74d81a6c MD	404	switch (obj->type) {
	405	case SHM_OBJECT_SHM:
	406	{
	407	int ret, i;
1d498196	408
7a784989 MD	409	ret = munmap(obj->memory_map, obj->memory_map_size);
	410	if (ret) {
	411	PERROR("umnmap");
	412	assert(0);
	413	}
ef9ff354 MD	414	ret = close(obj->shm_fd);
	415	if (ret) {
	416	PERROR("close");
	417	assert(0);
	418	}
74d81a6c MD	419	for (i = 0; i < 2; i++) {
	420	if (obj->wait_fd[i] < 0)
	421	continue;
	422	ret = close(obj->wait_fd[i]);
	423	if (ret) {
	424	PERROR("close");
	425	assert(0);
	426	}
1d498196	427	}
74d81a6c MD	428	break;
	429	}
	430	case SHM_OBJECT_MEM:
ff0f5728 MD	431	{
	432	int ret, i;
	433
	434	for (i = 0; i < 2; i++) {
	435	if (obj->wait_fd[i] < 0)
	436	continue;
	437	ret = close(obj->wait_fd[i]);
	438	if (ret) {
	439	PERROR("close");
	440	assert(0);
	441	}
	442	}
74d81a6c MD	443	free(obj->memory_map);
74d81a6c MD	444	break;
ff0f5728	445	}
74d81a6c MD	446	default:
74d81a6c MD	447	assert(0);
1d498196 MD	448	}
	449	}
	450
	451	void shm_object_table_destroy(struct shm_object_table *table)
	452	{
	453	int i;
	454
	455	for (i = 0; i < table->allocated_len; i++)
	456	shmp_object_destroy(&table->objects[i]);
	457	free(table);
	458	}
	459
	460	/*
	461	* zalloc_shm - allocate memory within a shm object.
	462	*
	463	* Shared memory is already zeroed by shmget.
	464	* NOT multithread-safe (should be protected by mutex).
	465	* Returns a -1, -1 tuple on error.
	466	*/
	467	struct shm_ref zalloc_shm(struct shm_object *obj, size_t len)
	468	{
	469	struct shm_ref ref;
	470	struct shm_ref shm_ref_error = { -1, -1 };
	471
	472	if (obj->memory_map_size - obj->allocated_len < len)
	473	return shm_ref_error;
	474	ref.index = obj->index;
	475	ref.offset = obj->allocated_len;
	476	obj->allocated_len += len;
	477	return ref;
	478	}
	479
	480	void align_shm(struct shm_object *obj, size_t align)
	481	{
	482	size_t offset_len = offset_align(obj->allocated_len, align);
	483	obj->allocated_len += offset_len;
	484	}