return table;
}
-static
-int create_posix_shm(void)
-{
- char tmp_name[NAME_MAX] = "/ust-shm-tmp-XXXXXX";
- int shmfd, ret;
-
- /*
- * Allocate shm, and immediately unlink its shm oject, keeping
- * only the file descriptor as a reference to the object. If it
- * already exists (caused by short race window during which the
- * global object exists in a concurrent shm_open), simply retry.
- * 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).
- */
- do {
- /*
- * Using mktemp filename with O_CREAT | O_EXCL open
- * flags.
- */
- (void) 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 || errno == EACCES));
- if (shmfd < 0) {
- PERROR("shm_open");
- goto error_shm_open;
- }
- ret = shm_unlink(tmp_name);
- if (ret < 0 && errno != ENOENT) {
- PERROR("shm_unlink");
- goto error_shm_release;
- }
- return shmfd;
-
-error_shm_release:
- ret = close(shmfd);
- if (ret) {
- PERROR("close");
- assert(0);
- }
-error_shm_open:
- return -1;
-}
-
-static
-int create_shared_file(const char *shm_path)
-{
- return open(shm_path, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
-}
-
static
struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table,
size_t memory_map_size,
- const char *shm_path)
+ int stream_fd)
{
- int shmfd, waitfd[2], ret, i, sigblocked = 0;
+ int shmfd, waitfd[2], ret, i;
struct shm_object *obj;
char *memory_map;
- sigset_t all_sigs, orig_sigs;
+ if (stream_fd < 0)
+ return NULL;
if (table->allocated_len >= table->size)
return NULL;
obj = &table->objects[table->allocated_len];
}
memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
- /* 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;
-
+ /* create shm */
- if (!shm_path) {
- obj->shm_path[0] = '\0';
- shmfd = create_posix_shm();
- } else {
- strncpy(obj->shm_path, shm_path,
- sizeof(obj->shm_path));
- obj->shm_path[sizeof(obj->shm_path) - 1] = '\0';
-
- /* Path should already exist, but could fail. */
- shmfd = create_shared_file(shm_path);
- }
- if (shmfd < 0)
- goto error_shm_open;
-
- sigblocked = 0;
- ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL);
- if (ret == -1) {
- PERROR("pthread_sigmask");
- goto error_sigmask_release;
- }
+ shmfd = stream_fd;
ret = zero_file(shmfd, memory_map_size);
if (ret) {
PERROR("zero_file");
PERROR("ftruncate");
goto error_ftruncate;
}
+ obj->shm_fd_ownership = 0;
obj->shm_fd = shmfd;
/* memory_map: mmap */
error_mmap:
error_ftruncate:
error_zero_file:
-error_sigmask_release:
- ret = close(shmfd);
- if (ret) {
- PERROR("close");
- assert(0);
- }
- if (shm_path) {
- ret = unlink(shm_path);
- if (ret) {
- PERROR("ret");
- }
- }
-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]);
/* no shm_fd */
obj->shm_fd = -1;
+ obj->shm_fd_ownership = 0;
obj->type = SHM_OBJECT_MEM;
obj->memory_map = memory_map;
struct shm_object *shm_object_table_alloc(struct shm_object_table *table,
size_t memory_map_size,
enum shm_object_type type,
- const char *shm_path)
+ int stream_fd)
{
switch (type) {
case SHM_OBJECT_SHM:
return _shm_object_table_alloc_shm(table, memory_map_size,
- shm_path);
+ stream_fd);
case SHM_OBJECT_MEM:
return _shm_object_table_alloc_mem(table, memory_map_size);
default:
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) {
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("umnmap");
assert(0);
}
- ret = close(obj->shm_fd);
- if (ret) {
- PERROR("close");
- assert(0);
- }
- if (obj->shm_path[0]) {
- ret = unlink(obj->shm_path);
+ if (obj->shm_fd_ownership) {
+ ret = close(obj->shm_fd);
if (ret) {
- PERROR("ret");
+ PERROR("close");
+ assert(0);
}
}
for (i = 0; i < 2; i++) {
projects / lttng-ust.git / blobdiff