[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
 */

#define _LGPL_SOURCE
#include "shm.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/types.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 <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 stream_fd)
{
	int shmfd, waitfd[2], ret, i;
	struct shm_object *obj;
	char *memory_map;

	if (stream_fd < 0)
		return NULL;
	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));

	/* create shm */

	shmfd = stream_fd;
	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_ownership = 0;
	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_zero_file:
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->shm_fd_ownership = 0;

	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,
			int stream_fd)
{
	switch (type) {
	case SHM_OBJECT_SHM:
		return _shm_object_table_alloc_shm(table, memory_map_size,
				stream_fd);
	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;
	obj->shm_fd_ownership = 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;
	}

	/* 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;
	obj->shm_fd_ownership = 0;

	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);
		}
		if (obj->shm_fd_ownership) {
			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	*/
1d498196 MD	20
3fbec7dc	21	#define _LGPL_SOURCE
1d498196 MD	22	#include "shm.h"
	23	#include <unistd.h>
	24	#include <fcntl.h>
	25	#include <sys/mman.h>
a9ff648c	26	#include <sys/types.h>
1d498196 MD	27	#include <sys/stat.h> /* For mode constants */
	28	#include <fcntl.h> /* For O_* constants */
	29	#include <assert.h>
8da6cd6d MD	30	#include <stdio.h>
	31	#include <signal.h>
	32	#include <dirent.h>
4318ae1b	33	#include <lttng/align.h>
96e80018	34	#include <limits.h>
3a81f31d MD	35	#include <helper.h>
	36
	37	/*
	38	* Ensure we have the required amount of space available by writing 0
	39	* into the entire buffer. Not doing so can trigger SIGBUS when going
	40	* beyond the available shm space.
	41	*/
	42	static
	43	int zero_file(int fd, size_t len)
	44	{
	45	ssize_t retlen;
	46	size_t written = 0;
	47	char *zeropage;
	48	long pagelen;
	49	int ret;
	50
	51	pagelen = sysconf(_SC_PAGESIZE);
	52	if (pagelen < 0)
	53	return (int) pagelen;
	54	zeropage = calloc(pagelen, 1);
	55	if (!zeropage)
	56	return -ENOMEM;
	57
	58	while (len > written) {
	59	do {
	60	retlen = write(fd, zeropage,
	61	min_t(size_t, pagelen, len - written));
	62	} while (retlen == -1UL && errno == EINTR);
	63	if (retlen < 0) {
	64	ret = (int) retlen;
	65	goto error;
	66	}
	67	written += retlen;
	68	}
	69	ret = 0;
	70	error:
	71	free(zeropage);
	72	return ret;
	73	}
1d498196 MD	74
	75	struct shm_object_table *shm_object_table_create(size_t max_nb_obj)
	76	{
	77	struct shm_object_table *table;
	78
	79	table = zmalloc(sizeof(struct shm_object_table) +
	80	max_nb_obj * sizeof(table->objects[0]));
74d48abe MD	81	if (!table)
74d48abe MD	82	return NULL;
1d498196 MD	83	table->size = max_nb_obj;
	84	return table;
	85	}
	86
74d81a6c MD	87	static
74d81a6c MD	88	struct shm_object _shm_object_table_alloc_shm(struct shm_object_table table,
a9ff648c	89	size_t memory_map_size,
5ea386c3	90	int stream_fd)
1d498196	91	{
5ea386c3	92	int shmfd, waitfd[2], ret, i;
1d498196 MD	93	struct shm_object *obj;
	94	char *memory_map;
	95
5ea386c3 MD	96	if (stream_fd < 0)
5ea386c3 MD	97	return NULL;
1d498196 MD	98	if (table->allocated_len >= table->size)
1d498196 MD	99	return NULL;
7a9c21bd	100	obj = &table->objects[table->allocated_len];
1d498196 MD	101
	102	/* wait_fd: create pipe */
	103	ret = pipe(waitfd);
	104	if (ret < 0) {
	105	PERROR("pipe");
	106	goto error_pipe;
	107	}
	108	for (i = 0; i < 2; i++) {
	109	ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
	110	if (ret < 0) {
	111	PERROR("fcntl");
	112	goto error_fcntl;
	113	}
	114	}
5d61a504 MD	115	/* The write end of the pipe needs to be non-blocking */
	116	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	117	if (ret < 0) {
	118	PERROR("fcntl");
	119	goto error_fcntl;
	120	}
7a9c21bd	121	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
1d498196	122
5ea386c3	123	/* create shm */
a9ff648c	124
5ea386c3	125	shmfd = stream_fd;
3a81f31d MD	126	ret = zero_file(shmfd, memory_map_size);
	127	if (ret) {
	128	PERROR("zero_file");
	129	goto error_zero_file;
	130	}
1d498196 MD	131	ret = ftruncate(shmfd, memory_map_size);
	132	if (ret) {
	133	PERROR("ftruncate");
	134	goto error_ftruncate;
	135	}
5ea386c3	136	obj->shm_fd_ownership = 0;
1d498196 MD	137	obj->shm_fd = shmfd;
	138
	139	/* memory_map: mmap */
	140	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	141	MAP_SHARED, shmfd, 0);
	142	if (memory_map == MAP_FAILED) {
	143	PERROR("mmap");
	144	goto error_mmap;
	145	}
74d81a6c	146	obj->type = SHM_OBJECT_SHM;
1d498196 MD	147	obj->memory_map = memory_map;
	148	obj->memory_map_size = memory_map_size;
	149	obj->allocated_len = 0;
dc613eb9	150	obj->index = table->allocated_len++;
7a9c21bd	151
1d498196 MD	152	return obj;
	153
	154	error_mmap:
	155	error_ftruncate:
3a81f31d	156	error_zero_file:
1d498196 MD	157	error_fcntl:
	158	for (i = 0; i < 2; i++) {
	159	ret = close(waitfd[i]);
	160	if (ret) {
	161	PERROR("close");
	162	assert(0);
	163	}
	164	}
	165	error_pipe:
1d498196	166	return NULL;
1d498196 MD	167	}
1d498196 MD	168
74d81a6c MD	169	static
	170	struct shm_object _shm_object_table_alloc_mem(struct shm_object_table table,
	171	size_t memory_map_size)
	172	{
	173	struct shm_object *obj;
	174	void *memory_map;
ff0f5728	175	int waitfd[2], i, ret;
74d81a6c MD	176
	177	if (table->allocated_len >= table->size)
	178	return NULL;
	179	obj = &table->objects[table->allocated_len];
	180
	181	memory_map = zmalloc(memory_map_size);
	182	if (!memory_map)
	183	goto alloc_error;
	184
ff0f5728 MD	185	/* wait_fd: create pipe */
	186	ret = pipe(waitfd);
	187	if (ret < 0) {
	188	PERROR("pipe");
	189	goto error_pipe;
	190	}
	191	for (i = 0; i < 2; i++) {
	192	ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
	193	if (ret < 0) {
	194	PERROR("fcntl");
	195	goto error_fcntl;
	196	}
	197	}
	198	/* The write end of the pipe needs to be non-blocking */
	199	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	200	if (ret < 0) {
	201	PERROR("fcntl");
	202	goto error_fcntl;
	203	}
	204	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
	205
	206	/* no shm_fd */
74d81a6c	207	obj->shm_fd = -1;
5ea386c3	208	obj->shm_fd_ownership = 0;
74d81a6c MD	209
	210	obj->type = SHM_OBJECT_MEM;
	211	obj->memory_map = memory_map;
	212	obj->memory_map_size = memory_map_size;
	213	obj->allocated_len = 0;
	214	obj->index = table->allocated_len++;
	215
	216	return obj;
	217
ff0f5728 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:
	227	free(memory_map);
74d81a6c MD	228	alloc_error:
	229	return NULL;
	230	}
	231
	232	struct shm_object shm_object_table_alloc(struct shm_object_table table,
	233	size_t memory_map_size,
a9ff648c	234	enum shm_object_type type,
5ea386c3	235	int stream_fd)
74d81a6c MD	236	{
	237	switch (type) {
	238	case SHM_OBJECT_SHM:
a9ff648c	239	return _shm_object_table_alloc_shm(table, memory_map_size,
5ea386c3	240	stream_fd);
74d81a6c MD	241	case SHM_OBJECT_MEM:
	242	return _shm_object_table_alloc_mem(table, memory_map_size);
	243	default:
	244	assert(0);
	245	}
	246	return NULL;
	247	}
	248
	249	struct shm_object shm_object_table_append_shm(struct shm_object_table table,
	250	int shm_fd, int wakeup_fd, uint32_t stream_nr,
	251	size_t memory_map_size)
193183fb MD	252	{
	253	struct shm_object *obj;
	254	char *memory_map;
74d81a6c	255	int ret;
193183fb MD	256
	257	if (table->allocated_len >= table->size)
	258	return NULL;
74d81a6c MD	259	/* streams _must_ be received in sequential order, else fail. */
	260	if (stream_nr + 1 != table->allocated_len)
	261	return NULL;
	262
193183fb MD	263	obj = &table->objects[table->allocated_len];
193183fb MD	264
74d81a6c MD	265	/* wait_fd: set write end of the pipe. */
	266	obj->wait_fd[0] = -1; /* read end is unset */
	267	obj->wait_fd[1] = wakeup_fd;
193183fb	268	obj->shm_fd = shm_fd;
5ea386c3	269	obj->shm_fd_ownership = 1;
193183fb	270
74d81a6c MD	271	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	272	if (ret < 0) {
	273	PERROR("fcntl");
	274	goto error_fcntl;
	275	}
	276	/* The write end of the pipe needs to be non-blocking */
	277	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	278	if (ret < 0) {
	279	PERROR("fcntl");
	280	goto error_fcntl;
	281	}
	282
193183fb MD	283	/* memory_map: mmap */
	284	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	285	MAP_SHARED, shm_fd, 0);
	286	if (memory_map == MAP_FAILED) {
	287	PERROR("mmap");
	288	goto error_mmap;
	289	}
74d81a6c	290	obj->type = SHM_OBJECT_SHM;
193183fb MD	291	obj->memory_map = memory_map;
	292	obj->memory_map_size = memory_map_size;
	293	obj->allocated_len = memory_map_size;
	294	obj->index = table->allocated_len++;
	295
	296	return obj;
	297
74d81a6c	298	error_fcntl:
193183fb MD	299	error_mmap:
	300	return NULL;
	301	}
	302
74d81a6c MD	303	/*
	304	* Passing ownership of mem to object.
	305	*/
	306	struct shm_object shm_object_table_append_mem(struct shm_object_table table,
ff0f5728	307	void *mem, size_t memory_map_size, int wakeup_fd)
74d81a6c MD	308	{
74d81a6c MD	309	struct shm_object *obj;
ff0f5728	310	int ret;
74d81a6c MD	311
	312	if (table->allocated_len >= table->size)
	313	return NULL;
	314	obj = &table->objects[table->allocated_len];
	315
ff0f5728 MD	316	obj->wait_fd[0] = -1; /* read end is unset */
ff0f5728 MD	317	obj->wait_fd[1] = wakeup_fd;
74d81a6c	318	obj->shm_fd = -1;
5ea386c3	319	obj->shm_fd_ownership = 0;
74d81a6c	320
ff0f5728 MD	321	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	322	if (ret < 0) {
	323	PERROR("fcntl");
	324	goto error_fcntl;
	325	}
	326	/* The write end of the pipe needs to be non-blocking */
	327	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	328	if (ret < 0) {
	329	PERROR("fcntl");
	330	goto error_fcntl;
	331	}
	332
74d81a6c MD	333	obj->type = SHM_OBJECT_MEM;
	334	obj->memory_map = mem;
	335	obj->memory_map_size = memory_map_size;
	336	obj->allocated_len = memory_map_size;
	337	obj->index = table->allocated_len++;
	338
	339	return obj;
ff0f5728 MD	340
	341	error_fcntl:
	342	return NULL;
74d81a6c MD	343	}
74d81a6c MD	344
1d498196 MD	345	static
	346	void shmp_object_destroy(struct shm_object *obj)
	347	{
74d81a6c MD	348	switch (obj->type) {
	349	case SHM_OBJECT_SHM:
	350	{
	351	int ret, i;
1d498196	352
7a784989 MD	353	ret = munmap(obj->memory_map, obj->memory_map_size);
	354	if (ret) {
	355	PERROR("umnmap");
	356	assert(0);
	357	}
5ea386c3 MD	358	if (obj->shm_fd_ownership) {
5ea386c3 MD	359	ret = close(obj->shm_fd);
a9ff648c	360	if (ret) {
5ea386c3 MD	361	PERROR("close");
5ea386c3 MD	362	assert(0);
a9ff648c MD	363	}
a9ff648c MD	364	}
74d81a6c MD	365	for (i = 0; i < 2; i++) {
	366	if (obj->wait_fd[i] < 0)
	367	continue;
	368	ret = close(obj->wait_fd[i]);
	369	if (ret) {
	370	PERROR("close");
	371	assert(0);
	372	}
1d498196	373	}
74d81a6c MD	374	break;
	375	}
	376	case SHM_OBJECT_MEM:
ff0f5728 MD	377	{
	378	int ret, i;
	379
	380	for (i = 0; i < 2; i++) {
	381	if (obj->wait_fd[i] < 0)
	382	continue;
	383	ret = close(obj->wait_fd[i]);
	384	if (ret) {
	385	PERROR("close");
	386	assert(0);
	387	}
	388	}
74d81a6c MD	389	free(obj->memory_map);
74d81a6c MD	390	break;
ff0f5728	391	}
74d81a6c MD	392	default:
74d81a6c MD	393	assert(0);
1d498196 MD	394	}
	395	}
	396
	397	void shm_object_table_destroy(struct shm_object_table *table)
	398	{
	399	int i;
	400
	401	for (i = 0; i < table->allocated_len; i++)
	402	shmp_object_destroy(&table->objects[i]);
	403	free(table);
	404	}
	405
	406	/*
	407	* zalloc_shm - allocate memory within a shm object.
	408	*
	409	* Shared memory is already zeroed by shmget.
	410	* NOT multithread-safe (should be protected by mutex).
	411	* Returns a -1, -1 tuple on error.
	412	*/
	413	struct shm_ref zalloc_shm(struct shm_object *obj, size_t len)
	414	{
	415	struct shm_ref ref;
	416	struct shm_ref shm_ref_error = { -1, -1 };
	417
	418	if (obj->memory_map_size - obj->allocated_len < len)
	419	return shm_ref_error;
	420	ref.index = obj->index;
	421	ref.offset = obj->allocated_len;
	422	obj->allocated_len += len;
	423	return ref;
	424	}
	425
	426	void align_shm(struct shm_object *obj, size_t align)
	427	{
	428	size_t offset_len = offset_align(obj->allocated_len, align);
	429	obj->allocated_len += offset_len;
	430	}