#include <sys/stat.h> /* For mode constants */
#include <fcntl.h> /* For O_* constants */
#include <assert.h>
-#include <ust/align.h>
+#include <stdio.h>
+#include <signal.h>
+#include <dirent.h>
+#include <lttng/align.h>
+#include <helper.h>
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";
+ sigset_t all_sigs, orig_sigs;
if (table->allocated_len >= table->size)
return NULL;
/* shm_fd: create shm */
+ /*
+ * Theoretically, we could leak a shm if the application crashes
+ * between open and unlink. Disable signals on this thread for
+ * increased safety against this scenario.
+ */
+ sigfillset(&all_sigs);
+ ret = pthread_sigmask(SIG_BLOCK, &all_sigs, &orig_sigs);
+ if (ret == -1) {
+ PERROR("pthread_sigmask");
+ goto error_pthread_sigmask;
+ }
+ sigblocked = 1;
+
/*
* Allocate shm, and immediately unlink its shm oject, keeping
* only the file descriptor as a reference to the object. If it
* We specifically do _not_ use the / at the beginning of the
* pathname so that some OS implementations can keep it local to
* the process (POSIX leaves this implementation-defined).
- * Ignore the shm_unlink errors, because we handle leaks that
- * could occur by applications crashing between shm_open and
- * shm_unlink by unlinking the shm before every open. Therefore,
- * we can only leak one single shm (and only if the application
- * crashes between shm_open and the following shm_unlink).
*/
do {
- (void) shm_unlink("ust-shm-tmp");
- shmfd = shm_open("ust-shm-tmp",
+ /*
+ * Using mktemp filename with O_CREAT | O_EXCL open
+ * flags.
+ */
+ mktemp(tmp_name);
+ if (tmp_name[0] == '\0') {
+ PERROR("mktemp");
+ goto error_shm_open;
+ }
+ shmfd = shm_open(tmp_name,
O_CREAT | O_EXCL | O_RDWR, 0700);
- } while (shmfd < 0 && errno == EEXIST);
+ } while (shmfd < 0 && (errno == EEXIST || errno == EACCES));
if (shmfd < 0) {
PERROR("shm_open");
goto error_shm_open;
}
- (void) shm_unlink("ust-shm-tmp");
+ ret = shm_unlink(tmp_name);
+ if (ret < 0 && errno != ENOENT) {
+ 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_sigmask_release;
+ }
ret = ftruncate(shmfd, memory_map_size);
if (ret) {
PERROR("ftruncate");
error_mmap:
error_ftruncate:
+error_shm_release:
+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++) {
ret = close(waitfd[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");