/*
* 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 <signal.h>
#include <dirent.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)
{
int shmfd, waitfd[2], ret, i, sigblocked = 0;
struct shm_object *obj;
char *memory_map;
- char tmp_name[NAME_MAX] = "ust-shm-tmp-XXXXXX";
+ char tmp_name[NAME_MAX] = "/ust-shm-tmp-XXXXXX";
sigset_t all_sigs, orig_sigs;
if (table->allocated_len >= table->size)
PERROR("pthread_sigmask");
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) {
PERROR("ftruncate");
error_mmap:
error_ftruncate:
error_shm_release:
+error_zero_file:
error_sigmask_release:
ret = close(shmfd);
if (ret) {
assert(0);
}
}
- ret = close(obj->shm_fd);
- if (ret) {
- PERROR("close");
- 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)