[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/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	*/
	20
	21	#include "shm.h"
	22	#include <unistd.h>
	23	#include <fcntl.h>
	24	#include <sys/mman.h>
a9ff648c	25	#include <sys/types.h>
1d498196 MD	26	#include <sys/stat.h> /* For mode constants */
	27	#include <fcntl.h> /* For O_* constants */
	28	#include <assert.h>
8da6cd6d MD	29	#include <stdio.h>
	30	#include <signal.h>
	31	#include <dirent.h>
4318ae1b	32	#include <lttng/align.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]));
74d48abe MD	80	if (!table)
74d48abe 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,
a9ff648c	88	size_t memory_map_size,
5ea386c3	89	int stream_fd)
1d498196	90	{
5ea386c3	91	int shmfd, waitfd[2], ret, i;
1d498196 MD	92	struct shm_object *obj;
	93	char *memory_map;
	94
5ea386c3 MD	95	if (stream_fd < 0)
5ea386c3 MD	96	return NULL;
1d498196 MD	97	if (table->allocated_len >= table->size)
1d498196 MD	98	return NULL;
7a9c21bd	99	obj = &table->objects[table->allocated_len];
1d498196 MD	100
	101	/* wait_fd: create pipe */
	102	ret = pipe(waitfd);
	103	if (ret < 0) {
	104	PERROR("pipe");
	105	goto error_pipe;
	106	}
	107	for (i = 0; i < 2; i++) {
	108	ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
	109	if (ret < 0) {
	110	PERROR("fcntl");
	111	goto error_fcntl;
	112	}
	113	}
5d61a504 MD	114	/* The write end of the pipe needs to be non-blocking */
	115	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	116	if (ret < 0) {
	117	PERROR("fcntl");
	118	goto error_fcntl;
	119	}
7a9c21bd	120	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
1d498196	121
5ea386c3	122	/* create shm */
a9ff648c	123
5ea386c3	124	shmfd = stream_fd;
3a81f31d MD	125	ret = zero_file(shmfd, memory_map_size);
	126	if (ret) {
	127	PERROR("zero_file");
	128	goto error_zero_file;
	129	}
1d498196 MD	130	ret = ftruncate(shmfd, memory_map_size);
	131	if (ret) {
	132	PERROR("ftruncate");
	133	goto error_ftruncate;
	134	}
5ea386c3	135	obj->shm_fd_ownership = 0;
1d498196 MD	136	obj->shm_fd = shmfd;
	137
	138	/* memory_map: mmap */
	139	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	140	MAP_SHARED, shmfd, 0);
	141	if (memory_map == MAP_FAILED) {
	142	PERROR("mmap");
	143	goto error_mmap;
	144	}
74d81a6c	145	obj->type = SHM_OBJECT_SHM;
1d498196 MD	146	obj->memory_map = memory_map;
	147	obj->memory_map_size = memory_map_size;
	148	obj->allocated_len = 0;
dc613eb9	149	obj->index = table->allocated_len++;
7a9c21bd	150
1d498196 MD	151	return obj;
	152
	153	error_mmap:
	154	error_ftruncate:
3a81f31d	155	error_zero_file:
1d498196 MD	156	error_fcntl:
	157	for (i = 0; i < 2; i++) {
	158	ret = close(waitfd[i]);
	159	if (ret) {
	160	PERROR("close");
	161	assert(0);
	162	}
	163	}
	164	error_pipe:
1d498196	165	return NULL;
1d498196 MD	166	}
1d498196 MD	167
74d81a6c MD	168	static
	169	struct shm_object _shm_object_table_alloc_mem(struct shm_object_table table,
	170	size_t memory_map_size)
	171	{
	172	struct shm_object *obj;
	173	void *memory_map;
ff0f5728	174	int waitfd[2], i, ret;
74d81a6c MD	175
	176	if (table->allocated_len >= table->size)
	177	return NULL;
	178	obj = &table->objects[table->allocated_len];
	179
	180	memory_map = zmalloc(memory_map_size);
	181	if (!memory_map)
	182	goto alloc_error;
	183
ff0f5728 MD	184	/* wait_fd: create pipe */
	185	ret = pipe(waitfd);
	186	if (ret < 0) {
	187	PERROR("pipe");
	188	goto error_pipe;
	189	}
	190	for (i = 0; i < 2; i++) {
	191	ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
	192	if (ret < 0) {
	193	PERROR("fcntl");
	194	goto error_fcntl;
	195	}
	196	}
	197	/* The write end of the pipe needs to be non-blocking */
	198	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	199	if (ret < 0) {
	200	PERROR("fcntl");
	201	goto error_fcntl;
	202	}
	203	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
	204
	205	/* no shm_fd */
74d81a6c	206	obj->shm_fd = -1;
5ea386c3	207	obj->shm_fd_ownership = 0;
74d81a6c MD	208
	209	obj->type = SHM_OBJECT_MEM;
	210	obj->memory_map = memory_map;
	211	obj->memory_map_size = memory_map_size;
	212	obj->allocated_len = 0;
	213	obj->index = table->allocated_len++;
	214
	215	return obj;
	216
ff0f5728 MD	217	error_fcntl:
	218	for (i = 0; i < 2; i++) {
	219	ret = close(waitfd[i]);
	220	if (ret) {
	221	PERROR("close");
	222	assert(0);
	223	}
	224	}
	225	error_pipe:
	226	free(memory_map);
74d81a6c MD	227	alloc_error:
	228	return NULL;
	229	}
	230
	231	struct shm_object shm_object_table_alloc(struct shm_object_table table,
	232	size_t memory_map_size,
a9ff648c	233	enum shm_object_type type,
5ea386c3	234	int stream_fd)
74d81a6c MD	235	{
	236	switch (type) {
	237	case SHM_OBJECT_SHM:
a9ff648c	238	return _shm_object_table_alloc_shm(table, memory_map_size,
5ea386c3	239	stream_fd);
74d81a6c MD	240	case SHM_OBJECT_MEM:
	241	return _shm_object_table_alloc_mem(table, memory_map_size);
	242	default:
	243	assert(0);
	244	}
	245	return NULL;
	246	}
	247
	248	struct shm_object shm_object_table_append_shm(struct shm_object_table table,
	249	int shm_fd, int wakeup_fd, uint32_t stream_nr,
	250	size_t memory_map_size)
193183fb MD	251	{
	252	struct shm_object *obj;
	253	char *memory_map;
74d81a6c	254	int ret;
193183fb MD	255
	256	if (table->allocated_len >= table->size)
	257	return NULL;
74d81a6c MD	258	/* streams _must_ be received in sequential order, else fail. */
	259	if (stream_nr + 1 != table->allocated_len)
	260	return NULL;
	261
193183fb MD	262	obj = &table->objects[table->allocated_len];
193183fb MD	263
74d81a6c MD	264	/* wait_fd: set write end of the pipe. */
	265	obj->wait_fd[0] = -1; /* read end is unset */
	266	obj->wait_fd[1] = wakeup_fd;
193183fb	267	obj->shm_fd = shm_fd;
5ea386c3	268	obj->shm_fd_ownership = 1;
193183fb	269
74d81a6c MD	270	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	271	if (ret < 0) {
	272	PERROR("fcntl");
	273	goto error_fcntl;
	274	}
	275	/* The write end of the pipe needs to be non-blocking */
	276	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	277	if (ret < 0) {
	278	PERROR("fcntl");
	279	goto error_fcntl;
	280	}
	281
193183fb MD	282	/* memory_map: mmap */
	283	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	284	MAP_SHARED, shm_fd, 0);
	285	if (memory_map == MAP_FAILED) {
	286	PERROR("mmap");
	287	goto error_mmap;
	288	}
74d81a6c	289	obj->type = SHM_OBJECT_SHM;
193183fb MD	290	obj->memory_map = memory_map;
	291	obj->memory_map_size = memory_map_size;
	292	obj->allocated_len = memory_map_size;
	293	obj->index = table->allocated_len++;
	294
	295	return obj;
	296
74d81a6c	297	error_fcntl:
193183fb MD	298	error_mmap:
	299	return NULL;
	300	}
	301
74d81a6c MD	302	/*
	303	* Passing ownership of mem to object.
	304	*/
	305	struct shm_object shm_object_table_append_mem(struct shm_object_table table,
ff0f5728	306	void *mem, size_t memory_map_size, int wakeup_fd)
74d81a6c MD	307	{
74d81a6c MD	308	struct shm_object *obj;
ff0f5728	309	int ret;
74d81a6c MD	310
	311	if (table->allocated_len >= table->size)
	312	return NULL;
	313	obj = &table->objects[table->allocated_len];
	314
ff0f5728 MD	315	obj->wait_fd[0] = -1; /* read end is unset */
ff0f5728 MD	316	obj->wait_fd[1] = wakeup_fd;
74d81a6c	317	obj->shm_fd = -1;
5ea386c3	318	obj->shm_fd_ownership = 0;
74d81a6c	319
ff0f5728 MD	320	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	321	if (ret < 0) {
	322	PERROR("fcntl");
	323	goto error_fcntl;
	324	}
	325	/* The write end of the pipe needs to be non-blocking */
	326	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	327	if (ret < 0) {
	328	PERROR("fcntl");
	329	goto error_fcntl;
	330	}
	331
74d81a6c MD	332	obj->type = SHM_OBJECT_MEM;
	333	obj->memory_map = mem;
	334	obj->memory_map_size = memory_map_size;
	335	obj->allocated_len = memory_map_size;
	336	obj->index = table->allocated_len++;
	337
	338	return obj;
ff0f5728 MD	339
	340	error_fcntl:
	341	return NULL;
74d81a6c MD	342	}
74d81a6c MD	343
1d498196 MD	344	static
	345	void shmp_object_destroy(struct shm_object *obj)
	346	{
74d81a6c MD	347	switch (obj->type) {
	348	case SHM_OBJECT_SHM:
	349	{
	350	int ret, i;
1d498196	351
7a784989 MD	352	ret = munmap(obj->memory_map, obj->memory_map_size);
	353	if (ret) {
	354	PERROR("umnmap");
	355	assert(0);
	356	}
5ea386c3 MD	357	if (obj->shm_fd_ownership) {
5ea386c3 MD	358	ret = close(obj->shm_fd);
a9ff648c	359	if (ret) {
5ea386c3 MD	360	PERROR("close");
5ea386c3 MD	361	assert(0);
a9ff648c MD	362	}
a9ff648c MD	363	}
74d81a6c MD	364	for (i = 0; i < 2; i++) {
	365	if (obj->wait_fd[i] < 0)
	366	continue;
	367	ret = close(obj->wait_fd[i]);
	368	if (ret) {
	369	PERROR("close");
	370	assert(0);
	371	}
1d498196	372	}
74d81a6c MD	373	break;
	374	}
	375	case SHM_OBJECT_MEM:
ff0f5728 MD	376	{
	377	int ret, i;
	378
	379	for (i = 0; i < 2; i++) {
	380	if (obj->wait_fd[i] < 0)
	381	continue;
	382	ret = close(obj->wait_fd[i]);
	383	if (ret) {
	384	PERROR("close");
	385	assert(0);
	386	}
	387	}
74d81a6c MD	388	free(obj->memory_map);
74d81a6c MD	389	break;
ff0f5728	390	}
74d81a6c MD	391	default:
74d81a6c MD	392	assert(0);
1d498196 MD	393	}
	394	}
	395
	396	void shm_object_table_destroy(struct shm_object_table *table)
	397	{
	398	int i;
	399
	400	for (i = 0; i < table->allocated_len; i++)
	401	shmp_object_destroy(&table->objects[i]);
	402	free(table);
	403	}
	404
	405	/*
	406	* zalloc_shm - allocate memory within a shm object.
	407	*
	408	* Shared memory is already zeroed by shmget.
	409	* NOT multithread-safe (should be protected by mutex).
	410	* Returns a -1, -1 tuple on error.
	411	*/
	412	struct shm_ref zalloc_shm(struct shm_object *obj, size_t len)
	413	{
	414	struct shm_ref ref;
	415	struct shm_ref shm_ref_error = { -1, -1 };
	416
	417	if (obj->memory_map_size - obj->allocated_len < len)
	418	return shm_ref_error;
	419	ref.index = obj->index;
	420	ref.offset = obj->allocated_len;
	421	obj->allocated_len += len;
	422	return ref;
	423	}
	424
	425	void align_shm(struct shm_object *obj, size_t align)
	426	{
	427	size_t offset_len = offset_align(obj->allocated_len, align);
	428	obj->allocated_len += offset_len;
	429	}