/*
* libringbuffer/shm.c
*
- * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * Dual LGPL v2.1/GPL v2 license.
+ * 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 <stdio.h>
#include <signal.h>
#include <dirent.h>
-#include <ust/align.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 *shm_object_table_append(struct shm_object_table *table,
size_t memory_map_size)
{
- int shmfd, waitfd[2], ret, i;
+ int shmfd, waitfd[2], ret, i, sigblocked = 0;
struct shm_object *obj;
char *memory_map;
char tmp_name[NAME_MAX] = "ust-shm-tmp-XXXXXX";
PERROR("pthread_sigmask");
goto error_pthread_sigmask;
}
+ sigblocked = 1;
/*
* Allocate shm, and immediately unlink its shm oject, keeping
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_shm_release;
+ 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) {
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++) {
}
+struct shm_object *shm_object_table_append_shadow(struct shm_object_table *table,
+ int shm_fd, int wait_fd, size_t memory_map_size)
+{
+ struct shm_object *obj;
+ char *memory_map;
+
+ if (table->allocated_len >= table->size)
+ return NULL;
+ obj = &table->objects[table->allocated_len];
+
+ /* wait_fd: set read end of the pipe. */
+ obj->wait_fd[0] = wait_fd;
+ obj->wait_fd[1] = -1; /* write end is unset. */
+ obj->shm_fd = shm_fd;
+
+ /* 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->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_mmap:
+ return NULL;
+}
+
static
void shmp_object_destroy(struct shm_object *obj)
{
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);
+ if (!obj->is_shadow) {
+ ret = munmap(obj->memory_map, obj->memory_map_size);
+ if (ret) {
+ PERROR("umnmap");
+ assert(0);
+ }
+ }
+ if (obj->shm_fd >= 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");
projects / lttng-ust.git / blobdiff