[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;
	}
	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, 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	}
5ea386c3	137	obj->shm_fd_ownership = 0;
1d498196 MD	138	obj->shm_fd = shmfd;
	139
	140	/* memory_map: mmap */
	141	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	142	MAP_SHARED, shmfd, 0);
	143	if (memory_map == MAP_FAILED) {
	144	PERROR("mmap");
	145	goto error_mmap;
	146	}
74d81a6c	147	obj->type = SHM_OBJECT_SHM;
1d498196 MD	148	obj->memory_map = memory_map;
	149	obj->memory_map_size = memory_map_size;
	150	obj->allocated_len = 0;
dc613eb9	151	obj->index = table->allocated_len++;
7a9c21bd	152
1d498196 MD	153	return obj;
	154
	155	error_mmap:
	156	error_ftruncate:
3a81f31d	157	error_zero_file:
1d498196 MD	158	error_fcntl:
	159	for (i = 0; i < 2; i++) {
	160	ret = close(waitfd[i]);
	161	if (ret) {
	162	PERROR("close");
	163	assert(0);
	164	}
	165	}
	166	error_pipe:
1d498196	167	return NULL;
1d498196 MD	168	}
1d498196 MD	169
74d81a6c MD	170	static
	171	struct shm_object _shm_object_table_alloc_mem(struct shm_object_table table,
	172	size_t memory_map_size)
	173	{
	174	struct shm_object *obj;
	175	void *memory_map;
ff0f5728	176	int waitfd[2], i, ret;
74d81a6c MD	177
	178	if (table->allocated_len >= table->size)
	179	return NULL;
	180	obj = &table->objects[table->allocated_len];
	181
	182	memory_map = zmalloc(memory_map_size);
	183	if (!memory_map)
	184	goto alloc_error;
	185
ff0f5728 MD	186	/* wait_fd: create pipe */
	187	ret = pipe(waitfd);
	188	if (ret < 0) {
	189	PERROR("pipe");
	190	goto error_pipe;
	191	}
	192	for (i = 0; i < 2; i++) {
	193	ret = fcntl(waitfd[i], F_SETFD, FD_CLOEXEC);
	194	if (ret < 0) {
	195	PERROR("fcntl");
	196	goto error_fcntl;
	197	}
	198	}
	199	/* The write end of the pipe needs to be non-blocking */
	200	ret = fcntl(waitfd[1], F_SETFL, O_NONBLOCK);
	201	if (ret < 0) {
	202	PERROR("fcntl");
	203	goto error_fcntl;
	204	}
	205	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
	206
	207	/* no shm_fd */
74d81a6c	208	obj->shm_fd = -1;
5ea386c3	209	obj->shm_fd_ownership = 0;
74d81a6c MD	210
	211	obj->type = SHM_OBJECT_MEM;
	212	obj->memory_map = memory_map;
	213	obj->memory_map_size = memory_map_size;
	214	obj->allocated_len = 0;
	215	obj->index = table->allocated_len++;
	216
	217	return obj;
	218
ff0f5728 MD	219	error_fcntl:
	220	for (i = 0; i < 2; i++) {
	221	ret = close(waitfd[i]);
	222	if (ret) {
	223	PERROR("close");
	224	assert(0);
	225	}
	226	}
	227	error_pipe:
	228	free(memory_map);
74d81a6c MD	229	alloc_error:
	230	return NULL;
	231	}
	232
	233	struct shm_object shm_object_table_alloc(struct shm_object_table table,
	234	size_t memory_map_size,
a9ff648c	235	enum shm_object_type type,
5ea386c3	236	int stream_fd)
74d81a6c MD	237	{
	238	switch (type) {
	239	case SHM_OBJECT_SHM:
a9ff648c	240	return _shm_object_table_alloc_shm(table, memory_map_size,
5ea386c3	241	stream_fd);
74d81a6c MD	242	case SHM_OBJECT_MEM:
	243	return _shm_object_table_alloc_mem(table, memory_map_size);
	244	default:
	245	assert(0);
	246	}
	247	return NULL;
	248	}
	249
	250	struct shm_object shm_object_table_append_shm(struct shm_object_table table,
	251	int shm_fd, int wakeup_fd, uint32_t stream_nr,
	252	size_t memory_map_size)
193183fb MD	253	{
	254	struct shm_object *obj;
	255	char *memory_map;
74d81a6c	256	int ret;
193183fb MD	257
	258	if (table->allocated_len >= table->size)
	259	return NULL;
74d81a6c MD	260	/* streams _must_ be received in sequential order, else fail. */
	261	if (stream_nr + 1 != table->allocated_len)
	262	return NULL;
	263
193183fb MD	264	obj = &table->objects[table->allocated_len];
193183fb MD	265
74d81a6c MD	266	/* wait_fd: set write end of the pipe. */
	267	obj->wait_fd[0] = -1; /* read end is unset */
	268	obj->wait_fd[1] = wakeup_fd;
193183fb	269	obj->shm_fd = shm_fd;
5ea386c3	270	obj->shm_fd_ownership = 1;
193183fb	271
74d81a6c MD	272	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	273	if (ret < 0) {
	274	PERROR("fcntl");
	275	goto error_fcntl;
	276	}
	277	/* The write end of the pipe needs to be non-blocking */
	278	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	279	if (ret < 0) {
	280	PERROR("fcntl");
	281	goto error_fcntl;
	282	}
	283
193183fb MD	284	/* memory_map: mmap */
	285	memory_map = mmap(NULL, memory_map_size, PROT_READ \| PROT_WRITE,
	286	MAP_SHARED, shm_fd, 0);
	287	if (memory_map == MAP_FAILED) {
	288	PERROR("mmap");
	289	goto error_mmap;
	290	}
74d81a6c	291	obj->type = SHM_OBJECT_SHM;
193183fb MD	292	obj->memory_map = memory_map;
	293	obj->memory_map_size = memory_map_size;
	294	obj->allocated_len = memory_map_size;
	295	obj->index = table->allocated_len++;
	296
	297	return obj;
	298
74d81a6c	299	error_fcntl:
193183fb MD	300	error_mmap:
	301	return NULL;
	302	}
	303
74d81a6c MD	304	/*
	305	* Passing ownership of mem to object.
	306	*/
	307	struct shm_object shm_object_table_append_mem(struct shm_object_table table,
ff0f5728	308	void *mem, size_t memory_map_size, int wakeup_fd)
74d81a6c MD	309	{
74d81a6c MD	310	struct shm_object *obj;
ff0f5728	311	int ret;
74d81a6c MD	312
	313	if (table->allocated_len >= table->size)
	314	return NULL;
	315	obj = &table->objects[table->allocated_len];
	316
ff0f5728 MD	317	obj->wait_fd[0] = -1; /* read end is unset */
ff0f5728 MD	318	obj->wait_fd[1] = wakeup_fd;
74d81a6c	319	obj->shm_fd = -1;
5ea386c3	320	obj->shm_fd_ownership = 0;
74d81a6c	321
ff0f5728 MD	322	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
	323	if (ret < 0) {
	324	PERROR("fcntl");
	325	goto error_fcntl;
	326	}
	327	/* The write end of the pipe needs to be non-blocking */
	328	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
	329	if (ret < 0) {
	330	PERROR("fcntl");
	331	goto error_fcntl;
	332	}
	333
74d81a6c MD	334	obj->type = SHM_OBJECT_MEM;
	335	obj->memory_map = mem;
	336	obj->memory_map_size = memory_map_size;
	337	obj->allocated_len = memory_map_size;
	338	obj->index = table->allocated_len++;
	339
	340	return obj;
ff0f5728 MD	341
	342	error_fcntl:
	343	return NULL;
74d81a6c MD	344	}
74d81a6c MD	345
1d498196	346	static
6548fca4	347	void shmp_object_destroy(struct shm_object *obj, int consumer)
1d498196	348	{
74d81a6c MD	349	switch (obj->type) {
	350	case SHM_OBJECT_SHM:
	351	{
	352	int ret, i;
1d498196	353
7a784989 MD	354	ret = munmap(obj->memory_map, obj->memory_map_size);
	355	if (ret) {
	356	PERROR("umnmap");
	357	assert(0);
	358	}
6548fca4	359
5ea386c3	360	if (obj->shm_fd_ownership) {
6548fca4 MD	361	/* Delete FDs only if called from app (not consumer). */
	362	if (!consumer) {
	363	lttng_ust_lock_fd_tracker();
	364	ret = close(obj->shm_fd);
	365	if (!ret) {
	366	lttng_ust_delete_fd_from_tracker(obj->shm_fd);
	367	} else {
	368	PERROR("close");
	369	assert(0);
	370	}
	371	lttng_ust_unlock_fd_tracker();
	372	} else {
	373	ret = close(obj->shm_fd);
	374	if (ret) {
	375	PERROR("close");
	376	assert(0);
	377	}
a9ff648c MD	378	}
a9ff648c MD	379	}
74d81a6c MD	380	for (i = 0; i < 2; i++) {
	381	if (obj->wait_fd[i] < 0)
	382	continue;
6548fca4 MD	383	if (!consumer) {
	384	lttng_ust_lock_fd_tracker();
	385	ret = close(obj->wait_fd[i]);
	386	if (!ret) {
	387	lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]);
	388	} else {
	389	PERROR("close");
	390	assert(0);
	391	}
	392	lttng_ust_unlock_fd_tracker();
	393	} else {
	394	ret = close(obj->wait_fd[i]);
	395	if (ret) {
	396	PERROR("close");
	397	assert(0);
	398	}
74d81a6c	399	}
1d498196	400	}
74d81a6c MD	401	break;
	402	}
	403	case SHM_OBJECT_MEM:
ff0f5728 MD	404	{
	405	int ret, i;
	406
	407	for (i = 0; i < 2; i++) {
	408	if (obj->wait_fd[i] < 0)
	409	continue;
6548fca4 MD	410	if (!consumer) {
	411	lttng_ust_lock_fd_tracker();
	412	ret = close(obj->wait_fd[i]);
	413	if (!ret) {
	414	lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]);
	415	} else {
	416	PERROR("close");
	417	assert(0);
	418	}
	419	lttng_ust_unlock_fd_tracker();
	420	} else {
	421	ret = close(obj->wait_fd[i]);
	422	if (ret) {
	423	PERROR("close");
	424	assert(0);
	425	}
ff0f5728 MD	426	}
ff0f5728 MD	427	}
74d81a6c MD	428	free(obj->memory_map);
74d81a6c MD	429	break;
ff0f5728	430	}
74d81a6c MD	431	default:
74d81a6c MD	432	assert(0);
1d498196 MD	433	}
	434	}
	435
6548fca4	436	void shm_object_table_destroy(struct shm_object_table *table, int consumer)
1d498196 MD	437	{
	438	int i;
	439
	440	for (i = 0; i < table->allocated_len; i++)
6548fca4	441	shmp_object_destroy(&table->objects[i], consumer);
1d498196 MD	442	free(table);
	443	}
	444
	445	/*
	446	* zalloc_shm - allocate memory within a shm object.
	447	*
	448	* Shared memory is already zeroed by shmget.
	449	* NOT multithread-safe (should be protected by mutex).
	450	* Returns a -1, -1 tuple on error.
	451	*/
	452	struct shm_ref zalloc_shm(struct shm_object *obj, size_t len)
	453	{
	454	struct shm_ref ref;
	455	struct shm_ref shm_ref_error = { -1, -1 };
	456
	457	if (obj->memory_map_size - obj->allocated_len < len)
	458	return shm_ref_error;
	459	ref.index = obj->index;
	460	ref.offset = obj->allocated_len;
	461	obj->allocated_len += len;
	462	return ref;
	463	}
	464
	465	void align_shm(struct shm_object *obj, size_t align)
	466	{
	467	size_t offset_len = offset_align(obj->allocated_len, align);
	468	obj->allocated_len += offset_len;
	469	}