* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the Free
- * Software Foundation; only version 2 of the License.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2 only,
+ * as published by the Free Software Foundation.
*
- * This program 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 General Public License for
- * more details.
+ * This program 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 General Public License for more details.
*
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
- * Place - Suite 330, Boston, MA 02111-1307, USA.
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
#include <fcntl.h>
#include <limits.h>
#include <sys/mman.h>
int wait_shm_fd, ret;
mode_t mode;
+ assert(shm_path);
+
/* Default permissions */
mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
- /* Change owner of the shm path */
+ /*
+ * Change owner of the shm path.
+ */
if (global) {
- ret = chown(shm_path, 0, 0);
- if (ret < 0) {
- if (errno != ENOENT) {
- perror("chown wait shm");
- goto error;
- }
- }
-
/*
- * If global session daemon, any application can register so the shm
- * needs to be set in read-only mode for others.
+ * If global session daemon, any application can
+ * register. Make it initially writeable so applications
+ * registering concurrently can do ftruncate() by
+ * themselves.
*/
- mode |= S_IROTH;
- } else {
- ret = chown(shm_path, getuid(), getgid());
- if (ret < 0) {
- if (errno != ENOENT) {
- perror("chown wait shm");
- goto error;
- }
- }
- }
-
- /*
- * Set permissions to the shm even if we did not create the shm.
- */
- ret = chmod(shm_path, mode);
- if (ret < 0) {
- if (errno != ENOENT) {
- perror("chmod wait shm");
- goto error;
- }
+ mode |= S_IROTH | S_IWOTH;
}
/*
*/
wait_shm_fd = shm_open(shm_path, O_RDWR | O_CREAT, mode);
if (wait_shm_fd < 0) {
- perror("shm_open wait shm");
+ PERROR("shm_open wait shm");
goto error;
}
ret = ftruncate(wait_shm_fd, mmap_size);
if (ret < 0) {
- perror("ftruncate wait shm");
+ PERROR("ftruncate wait shm");
exit(EXIT_FAILURE);
}
#ifndef __FreeBSD__
- ret = fchmod(wait_shm_fd, mode);
- if (ret < 0) {
- perror("fchmod");
- exit(EXIT_FAILURE);
+ if (global) {
+ ret = fchown(wait_shm_fd, 0, 0);
+ if (ret < 0) {
+ PERROR("fchown");
+ exit(EXIT_FAILURE);
+ }
+ /*
+ * If global session daemon, any application can
+ * register so the shm needs to be set in read-only mode
+ * for others.
+ */
+ mode &= ~S_IWOTH;
+ ret = fchmod(wait_shm_fd, mode);
+ if (ret < 0) {
+ PERROR("fchmod");
+ exit(EXIT_FAILURE);
+ }
+ } else {
+ ret = fchown(wait_shm_fd, getuid(), getgid());
+ if (ret < 0) {
+ PERROR("fchown");
+ exit(EXIT_FAILURE);
+ }
}
#else
-#warning "FreeBSD does not support setting file mode on shm FD. Remember that for secure use, lttng-sessiond should be started before applications linked on lttng-ust."
+#warning "FreeBSD does not support setting file mode on shm FD."
#endif
DBG("Got the wait shm fd %d", wait_shm_fd);
*/
char *shm_ust_get_mmap(char *shm_path, int global)
{
- size_t mmap_size = sysconf(_SC_PAGE_SIZE);
+ size_t mmap_size;
int wait_shm_fd, ret;
char *wait_shm_mmap;
+ long sys_page_size;
+
+ assert(shm_path);
+
+ sys_page_size = sysconf(_SC_PAGE_SIZE);
+ if (sys_page_size < 0) {
+ PERROR("sysconf PAGE_SIZE");
+ goto error;
+ }
+ mmap_size = sys_page_size;
wait_shm_fd = get_wait_shm(shm_path, mmap_size, global);
if (wait_shm_fd < 0) {
/* close shm fd immediately after taking the mmap reference */
ret = close(wait_shm_fd);
if (ret) {
- perror("Error closing fd");
+ PERROR("Error closing fd");
}
if (wait_shm_mmap == MAP_FAILED) {
projects / lttng-tools.git / blobdiff