int _sys_msgctl(int id, int cmd, void *buf)
{
struct msqid_ds ubuf;
msg_info_t *info;
info = msg_get_by_id(id);
if (!info) {
syscall_errno = EINVAL;
return -1;
}
switch (cmd) {
case IPC_STAT:
if (!ipc_have_permissions(&(info->info.msg_perm), IPC_PERM_READ)) {
syscall_errno = EACCES;
return -1;
}
if (!copy_kern_to_user(&(info->info), buf, sizeof(struct msqid_ds))){
syscall_errno = EFAULT;
return -1;
}
return 0;
case IPC_SET:
if ((!ipc_is_creator(&(info->info.msg_perm))) && !ipc_have_permissions(&(info->info.msg_perm), IPC_PERM_WRITE)) {
syscall_errno = EPERM;
return -1;
}
if (!copy_user_to_kern(buf, &ubuf, sizeof(struct msqid_ds))){
syscall_errno = EFAULT;
return -1;
}
info->info.msg_perm.uid = ubuf.msg_perm.uid;
info->info.msg_perm.gid = ubuf.msg_perm.gid;
info->info.msg_perm.mode &= ~0x1FF;
info->info.msg_perm.mode |= ubuf.msg_perm.mode & 0x1FF;
return 0;
case IPC_RMID:
if ((!ipc_is_creator(&(info->info.msg_perm))) && !ipc_have_permissions(&(info->info.msg_perm), IPC_PERM_WRITE)) {
syscall_errno = EPERM;
return -1;
}
info->del = 1;
if (!info->refs) {
msg_do_delete(info);
} else {
semaphore_add(info->rwaitsem, 999999);
semaphore_add(info->swaitsem, 999999);
}
return 0;
default:
syscall_errno = EINVAL;
return -1;
}
}
static int
jack_shm_lock_registry (void)
{
if (semid == -1) {
if (semaphore_init () < 0)
return -1;
}
return semaphore_add (-1);
}
static void
jack_shm_unlock_registry (void)
{
semaphore_add (1);
}