[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>
#include <ust-fd.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;
	}
	/*
	 * Also ensure the file metadata is synced with the storage by using
	 * fsync(2).
	 */
	ret = fsync(shmfd);
	if (ret) {
		PERROR("fsync");
		goto error_fsync;
	}
	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_fsync:
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, int consumer)
{
	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) {
			/* Delete FDs only if called from app (not consumer). */
			if (!consumer) {
				lttng_ust_lock_fd_tracker();
				ret = close(obj->shm_fd);
				if (!ret) {
					lttng_ust_delete_fd_from_tracker(obj->shm_fd);
				} else {
					PERROR("close");
					assert(0);
				}
				lttng_ust_unlock_fd_tracker();
			} else {
				ret = close(obj->shm_fd);
				if (ret) {
					PERROR("close");
					assert(0);
				}
			}
		}
		for (i = 0; i < 2; i++) {
			if (obj->wait_fd[i] < 0)
				continue;
			if (!consumer) {
				lttng_ust_lock_fd_tracker();
				ret = close(obj->wait_fd[i]);
				if (!ret) {
					lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]);
				} else {
					PERROR("close");
					assert(0);
				}
				lttng_ust_unlock_fd_tracker();
			} else {
				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;
			if (!consumer) {
				lttng_ust_lock_fd_tracker();
				ret = close(obj->wait_fd[i]);
				if (!ret) {
					lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]);
				} else {
					PERROR("close");
					assert(0);
				}
				lttng_ust_unlock_fd_tracker();
			} else {
				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 consumer)
{
	int i;

	for (i = 0; i < table->allocated_len; i++)
		shmp_object_destroy(&table->objects[i], consumer);
	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	35	#include <helper.h>
6548fca4	36	#include <ust-fd.h>
3a81f31d MD	37
	38	/*
	39	* Ensure we have the required amount of space available by writing 0
	40	* into the entire buffer. Not doing so can trigger SIGBUS when going
	41	* beyond the available shm space.
	42	*/
	43	static
	44	int zero_file(int fd, size_t len)
	45	{
	46	ssize_t retlen;
	47	size_t written = 0;
	48	char *zeropage;
	49	long pagelen;
	50	int ret;
	51
	52	pagelen = sysconf(_SC_PAGESIZE);
	53	if (pagelen < 0)
	54	return (int) pagelen;
	55	zeropage = calloc(pagelen, 1);
	56	if (!zeropage)
	57	return -ENOMEM;
	58
	59	while (len > written) {
	60	do {
	61	retlen = write(fd, zeropage,
	62	min_t(size_t, pagelen, len - written));
	63	} while (retlen == -1UL && errno == EINTR);
	64	if (retlen < 0) {
	65	ret = (int) retlen;
	66	goto error;
	67	}
	68	written += retlen;
	69	}
	70	ret = 0;
	71	error:
	72	free(zeropage);
	73	return ret;
	74	}
1d498196 MD	75
	76	struct shm_object_table *shm_object_table_create(size_t max_nb_obj)
	77	{
	78	struct shm_object_table *table;
	79
	80	table = zmalloc(sizeof(struct shm_object_table) +
	81	max_nb_obj * sizeof(table->objects[0]));
74d48abe MD	82	if (!table)
74d48abe MD	83	return NULL;
1d498196 MD	84	table->size = max_nb_obj;
	85	return table;
	86	}
	87
74d81a6c MD	88	static
74d81a6c MD	89	struct shm_object _shm_object_table_alloc_shm(struct shm_object_table table,
a9ff648c	90	size_t memory_map_size,
5ea386c3	91	int stream_fd)
1d498196	92	{
5ea386c3	93	int shmfd, waitfd[2], ret, i;
1d498196 MD	94	struct shm_object *obj;
	95	char *memory_map;
	96
5ea386c3 MD	97	if (stream_fd < 0)
5ea386c3 MD	98	return NULL;
1d498196 MD	99	if (table->allocated_len >= table->size)
1d498196 MD	100	return NULL;
7a9c21bd	101	obj = &table->objects[table->allocated_len];
1d498196 MD	102
	103	/* wait_fd: create pipe */
	104	ret = pipe(waitfd);
	105	if (ret < 0) {
	106	PERROR("pipe");
	107	goto error_pipe;
	108	}
	109	for (i = 0; i < 2; i++) {
	110	ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
	111	if (ret < 0) {
	112	PERROR("fcntl");
	113	goto error_fcntl;
	114	}
	115	}
5d61a504 MD	116	/* The write end of the pipe needs to be non-blocking */
	117	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	118	if (ret < 0) {
	119	PERROR("fcntl");
	120	goto error_fcntl;
	121	}
7a9c21bd	122	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
1d498196	123
5ea386c3	124	/* create shm */
a9ff648c	125
5ea386c3	126	shmfd = stream_fd;
3a81f31d MD	127	ret = zero_file(shmfd, memory_map_size);
	128	if (ret) {
	129	PERROR("zero_file");
	130	goto error_zero_file;
	131	}
1d498196 MD	132	ret = ftruncate(shmfd, memory_map_size);
	133	if (ret) {
	134	PERROR("ftruncate");
	135	goto error_ftruncate;
	136	}
d0f6cf57 MD	137	/*
	138	* Also ensure the file metadata is synced with the storage by using
	139	* fsync(2).
	140	*/
	141	ret = fsync(shmfd);
	142	if (ret) {
	143	PERROR("fsync");
	144	goto error_fsync;
	145	}
5ea386c3	146	obj->shm_fd_ownership = 0;
1d498196 MD	147	obj->shm_fd = shmfd;
	148
	149	/* memory_map: mmap */
	150	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	151	MAP_SHARED, shmfd, 0);
	152	if (memory_map == MAP_FAILED) {
	153	PERROR("mmap");
	154	goto error_mmap;
	155	}
74d81a6c	156	obj->type = SHM_OBJECT_SHM;
1d498196 MD	157	obj->memory_map = memory_map;
	158	obj->memory_map_size = memory_map_size;
	159	obj->allocated_len = 0;
dc613eb9	160	obj->index = table->allocated_len++;
7a9c21bd	161
1d498196 MD	162	return obj;
	163
	164	error_mmap:
d0f6cf57	165	error_fsync:
1d498196	166	error_ftruncate:
3a81f31d	167	error_zero_file:
1d498196 MD	168	error_fcntl:
	169	for (i = 0; i < 2; i++) {
	170	ret = close(waitfd[i]);
	171	if (ret) {
	172	PERROR("close");
	173	assert(0);
	174	}
	175	}
	176	error_pipe:
1d498196	177	return NULL;
1d498196 MD	178	}
1d498196 MD	179
74d81a6c MD	180	static
	181	struct shm_object _shm_object_table_alloc_mem(struct shm_object_table table,
	182	size_t memory_map_size)
	183	{
	184	struct shm_object *obj;
	185	void *memory_map;
ff0f5728	186	int waitfd[2], i, ret;
74d81a6c MD	187
	188	if (table->allocated_len >= table->size)
	189	return NULL;
	190	obj = &table->objects[table->allocated_len];
	191
	192	memory_map = zmalloc(memory_map_size);
	193	if (!memory_map)
	194	goto alloc_error;
	195
ff0f5728 MD	196	/* wait_fd: create pipe */
	197	ret = pipe(waitfd);
	198	if (ret < 0) {
	199	PERROR("pipe");
	200	goto error_pipe;
	201	}
	202	for (i = 0; i < 2; i++) {
	203	ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
	204	if (ret < 0) {
	205	PERROR("fcntl");
	206	goto error_fcntl;
	207	}
	208	}
	209	/* The write end of the pipe needs to be non-blocking */
	210	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	211	if (ret < 0) {
	212	PERROR("fcntl");
	213	goto error_fcntl;
	214	}
	215	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
	216
	217	/* no shm_fd */
74d81a6c	218	obj->shm_fd = -1;
5ea386c3	219	obj->shm_fd_ownership = 0;
74d81a6c MD	220
	221	obj->type = SHM_OBJECT_MEM;
	222	obj->memory_map = memory_map;
	223	obj->memory_map_size = memory_map_size;
	224	obj->allocated_len = 0;
	225	obj->index = table->allocated_len++;
	226
	227	return obj;
	228
ff0f5728 MD	229	error_fcntl:
	230	for (i = 0; i < 2; i++) {
	231	ret = close(waitfd[i]);
	232	if (ret) {
	233	PERROR("close");
	234	assert(0);
	235	}
	236	}
	237	error_pipe:
	238	free(memory_map);
74d81a6c MD	239	alloc_error:
	240	return NULL;
	241	}
	242
	243	struct shm_object shm_object_table_alloc(struct shm_object_table table,
	244	size_t memory_map_size,
a9ff648c	245	enum shm_object_type type,
5ea386c3	246	int stream_fd)
74d81a6c MD	247	{
	248	switch (type) {
	249	case SHM_OBJECT_SHM:
a9ff648c	250	return _shm_object_table_alloc_shm(table, memory_map_size,
5ea386c3	251	stream_fd);
74d81a6c MD	252	case SHM_OBJECT_MEM:
	253	return _shm_object_table_alloc_mem(table, memory_map_size);
	254	default:
	255	assert(0);
	256	}
	257	return NULL;
	258	}
	259
	260	struct shm_object shm_object_table_append_shm(struct shm_object_table table,
	261	int shm_fd, int wakeup_fd, uint32_t stream_nr,
	262	size_t memory_map_size)
193183fb MD	263	{
	264	struct shm_object *obj;
	265	char *memory_map;
74d81a6c	266	int ret;
193183fb MD	267
	268	if (table->allocated_len >= table->size)
	269	return NULL;
74d81a6c MD	270	/* streams _must_ be received in sequential order, else fail. */
	271	if (stream_nr + 1 != table->allocated_len)
	272	return NULL;
	273
193183fb MD	274	obj = &table->objects[table->allocated_len];
193183fb MD	275
74d81a6c MD	276	/* wait_fd: set write end of the pipe. */
	277	obj->wait_fd[0] = -1; /* read end is unset */
	278	obj->wait_fd[1] = wakeup_fd;
193183fb	279	obj->shm_fd = shm_fd;
5ea386c3	280	obj->shm_fd_ownership = 1;
193183fb	281
74d81a6c MD	282	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	283	if (ret < 0) {
	284	PERROR("fcntl");
	285	goto error_fcntl;
	286	}
	287	/* The write end of the pipe needs to be non-blocking */
	288	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	289	if (ret < 0) {
	290	PERROR("fcntl");
	291	goto error_fcntl;
	292	}
	293
193183fb MD	294	/* memory_map: mmap */
	295	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	296	MAP_SHARED, shm_fd, 0);
	297	if (memory_map == MAP_FAILED) {
	298	PERROR("mmap");
	299	goto error_mmap;
	300	}
74d81a6c	301	obj->type = SHM_OBJECT_SHM;
193183fb MD	302	obj->memory_map = memory_map;
	303	obj->memory_map_size = memory_map_size;
	304	obj->allocated_len = memory_map_size;
	305	obj->index = table->allocated_len++;
	306
	307	return obj;
	308
74d81a6c	309	error_fcntl:
193183fb MD	310	error_mmap:
	311	return NULL;
	312	}
	313
74d81a6c MD	314	/*
	315	* Passing ownership of mem to object.
	316	*/
	317	struct shm_object shm_object_table_append_mem(struct shm_object_table table,
ff0f5728	318	void *mem, size_t memory_map_size, int wakeup_fd)
74d81a6c MD	319	{
74d81a6c MD	320	struct shm_object *obj;
ff0f5728	321	int ret;
74d81a6c MD	322
	323	if (table->allocated_len >= table->size)
	324	return NULL;
	325	obj = &table->objects[table->allocated_len];
	326
ff0f5728 MD	327	obj->wait_fd[0] = -1; /* read end is unset */
ff0f5728 MD	328	obj->wait_fd[1] = wakeup_fd;
74d81a6c	329	obj->shm_fd = -1;
5ea386c3	330	obj->shm_fd_ownership = 0;
74d81a6c	331
ff0f5728 MD	332	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	333	if (ret < 0) {
	334	PERROR("fcntl");
	335	goto error_fcntl;
	336	}
	337	/* The write end of the pipe needs to be non-blocking */
	338	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	339	if (ret < 0) {
	340	PERROR("fcntl");
	341	goto error_fcntl;
	342	}
	343
74d81a6c MD	344	obj->type = SHM_OBJECT_MEM;
	345	obj->memory_map = mem;
	346	obj->memory_map_size = memory_map_size;
	347	obj->allocated_len = memory_map_size;
	348	obj->index = table->allocated_len++;
	349
	350	return obj;
ff0f5728 MD	351
	352	error_fcntl:
	353	return NULL;
74d81a6c MD	354	}
74d81a6c MD	355
1d498196	356	static
6548fca4	357	void shmp_object_destroy(struct shm_object *obj, int consumer)
1d498196	358	{
74d81a6c MD	359	switch (obj->type) {
	360	case SHM_OBJECT_SHM:
	361	{
	362	int ret, i;
1d498196	363
7a784989 MD	364	ret = munmap(obj->memory_map, obj->memory_map_size);
	365	if (ret) {
	366	PERROR("umnmap");
	367	assert(0);
	368	}
6548fca4	369
5ea386c3	370	if (obj->shm_fd_ownership) {
6548fca4 MD	371	/* Delete FDs only if called from app (not consumer). */
	372	if (!consumer) {
	373	lttng_ust_lock_fd_tracker();
	374	ret = close(obj->shm_fd);
	375	if (!ret) {
	376	lttng_ust_delete_fd_from_tracker(obj->shm_fd);
	377	} else {
	378	PERROR("close");
	379	assert(0);
	380	}
	381	lttng_ust_unlock_fd_tracker();
	382	} else {
	383	ret = close(obj->shm_fd);
	384	if (ret) {
	385	PERROR("close");
	386	assert(0);
	387	}
a9ff648c MD	388	}
a9ff648c MD	389	}
74d81a6c MD	390	for (i = 0; i < 2; i++) {
	391	if (obj->wait_fd[i] < 0)
	392	continue;
6548fca4 MD	393	if (!consumer) {
	394	lttng_ust_lock_fd_tracker();
	395	ret = close(obj->wait_fd[i]);
	396	if (!ret) {
	397	lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]);
	398	} else {
	399	PERROR("close");
	400	assert(0);
	401	}
	402	lttng_ust_unlock_fd_tracker();
	403	} else {
	404	ret = close(obj->wait_fd[i]);
	405	if (ret) {
	406	PERROR("close");
	407	assert(0);
	408	}
74d81a6c	409	}
1d498196	410	}
74d81a6c MD	411	break;
	412	}
	413	case SHM_OBJECT_MEM:
ff0f5728 MD	414	{
	415	int ret, i;
	416
	417	for (i = 0; i < 2; i++) {
	418	if (obj->wait_fd[i] < 0)
	419	continue;
6548fca4 MD	420	if (!consumer) {
	421	lttng_ust_lock_fd_tracker();
	422	ret = close(obj->wait_fd[i]);
	423	if (!ret) {
	424	lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]);
	425	} else {
	426	PERROR("close");
	427	assert(0);
	428	}
	429	lttng_ust_unlock_fd_tracker();
	430	} else {
	431	ret = close(obj->wait_fd[i]);
	432	if (ret) {
	433	PERROR("close");
	434	assert(0);
	435	}
ff0f5728 MD	436	}
ff0f5728 MD	437	}
74d81a6c MD	438	free(obj->memory_map);
74d81a6c MD	439	break;
ff0f5728	440	}
74d81a6c MD	441	default:
74d81a6c MD	442	assert(0);
1d498196 MD	443	}
	444	}
	445
6548fca4	446	void shm_object_table_destroy(struct shm_object_table *table, int consumer)
1d498196 MD	447	{
	448	int i;
	449
	450	for (i = 0; i < table->allocated_len; i++)
6548fca4	451	shmp_object_destroy(&table->objects[i], consumer);
1d498196 MD	452	free(table);
	453	}
	454
	455	/*
	456	* zalloc_shm - allocate memory within a shm object.
	457	*
	458	* Shared memory is already zeroed by shmget.
	459	* NOT multithread-safe (should be protected by mutex).
	460	* Returns a -1, -1 tuple on error.
	461	*/
	462	struct shm_ref zalloc_shm(struct shm_object *obj, size_t len)
	463	{
	464	struct shm_ref ref;
	465	struct shm_ref shm_ref_error = { -1, -1 };
	466
	467	if (obj->memory_map_size - obj->allocated_len < len)
	468	return shm_ref_error;
	469	ref.index = obj->index;
	470	ref.offset = obj->allocated_len;
	471	obj->allocated_len += len;
	472	return ref;
	473	}
	474
	475	void align_shm(struct shm_object *obj, size_t align)
	476	{
	477	size_t offset_len = offset_align(obj->allocated_len, align);
	478	obj->allocated_len += offset_len;
	479	}