static void
ksem_insert(char *path, Fnv32_t fnv, struct ksem *ks)
{
struct ksem_mapping *map;
map = malloc(sizeof(struct ksem_mapping), M_KSEM, M_WAITOK);
map->km_path = path;
map->km_fnv = fnv;
map->km_ksem = ksem_hold(ks);
LIST_INSERT_HEAD(KSEM_HASH(fnv), map, km_link);
}
/* Other helper routines. */
static int
ksem_create(struct thread *td, const char *name, semid_t *semidp, mode_t mode,
unsigned int value, int flags, int compat32)
{
struct filedesc *fdp;
struct ksem *ks;
struct file *fp;
char *path;
Fnv32_t fnv;
int error, fd;
if (value > SEM_VALUE_MAX)
return (EINVAL);
fdp = td->td_proc->p_fd;
mode = (mode & ~fdp->fd_cmask) & ACCESSPERMS;
error = falloc(td, &fp, &fd, O_CLOEXEC);
if (error) {
if (name == NULL)
error = ENOSPC;
return (error);
}
/*
* Go ahead and copyout the file descriptor now. This is a bit
* premature, but it is a lot easier to handle errors as opposed
* to later when we've possibly created a new semaphore, etc.
*/
error = ksem_create_copyout_semid(td, semidp, fd, compat32);
if (error) {
fdclose(fdp, fp, fd, td);
fdrop(fp, td);
return (error);
}
if (name == NULL) {
/* Create an anonymous semaphore. */
ks = ksem_alloc(td->td_ucred, mode, value);
if (ks == NULL)
error = ENOSPC;
else
ks->ks_flags |= KS_ANONYMOUS;
} else {
path = malloc(MAXPATHLEN, M_KSEM, M_WAITOK);
error = copyinstr(name, path, MAXPATHLEN, NULL);
/* Require paths to start with a '/' character. */
if (error == 0 && path[0] != '/')
error = EINVAL;
if (error) {
fdclose(fdp, fp, fd, td);
fdrop(fp, td);
free(path, M_KSEM);
return (error);
}
fnv = fnv_32_str(path, FNV1_32_INIT);
sx_xlock(&ksem_dict_lock);
ks = ksem_lookup(path, fnv);
if (ks == NULL) {
/* Object does not exist, create it if requested. */
if (flags & O_CREAT) {
ks = ksem_alloc(td->td_ucred, mode, value);
if (ks == NULL)
error = ENFILE;
else {
ksem_insert(path, fnv, ks);
path = NULL;
}
} else
error = ENOENT;
} else {
/*
* Object already exists, obtain a new
* reference if requested and permitted.
*/
if ((flags & (O_CREAT | O_EXCL)) ==
(O_CREAT | O_EXCL))
error = EEXIST;
else {
#ifdef MAC
error = mac_posixsem_check_open(td->td_ucred,
ks);
if (error == 0)
#endif
error = ksem_access(ks, td->td_ucred);
}
if (error == 0)
ksem_hold(ks);
#ifdef INVARIANTS
else
ks = NULL;
#endif
}
sx_xunlock(&ksem_dict_lock);
if (path)
free(path, M_KSEM);
}
if (error) {
KASSERT(ks == NULL, ("ksem_create error with a ksem"));
fdclose(fdp, fp, fd, td);
fdrop(fp, td);
return (error);
}
KASSERT(ks != NULL, ("ksem_create w/o a ksem"));
finit(fp, FREAD | FWRITE, DTYPE_SEM, ks, &ksem_ops);
fdrop(fp, td);
return (0);
}