-static int openpt_in_namespace(pid_t pid, int flags) {
- _cleanup_close_pair_ int pair[2] = { -1, -1 };
- _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, rootfd = -1;
- union {
- struct cmsghdr cmsghdr;
- uint8_t buf[CMSG_SPACE(sizeof(int))];
- } control = {};
- struct msghdr mh = {
- .msg_control = &control,
- .msg_controllen = sizeof(control),
- };
- struct cmsghdr *cmsg;
- int master = -1, r;
- pid_t child;
- siginfo_t si;
-
- assert(pid > 0);
-
- r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &rootfd);
- if (r < 0)
- return r;
-
- if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
- return -errno;
-
- child = fork();
- if (child < 0)
- return -errno;
-
- if (child == 0) {
- pair[0] = safe_close(pair[0]);
-
- r = namespace_enter(pidnsfd, mntnsfd, -1, rootfd);
- if (r < 0)
- _exit(EXIT_FAILURE);
-
- master = posix_openpt(flags);
- if (master < 0)
- _exit(EXIT_FAILURE);
-
- cmsg = CMSG_FIRSTHDR(&mh);
- cmsg->cmsg_level = SOL_SOCKET;
- cmsg->cmsg_type = SCM_RIGHTS;
- cmsg->cmsg_len = CMSG_LEN(sizeof(int));
- memcpy(CMSG_DATA(cmsg), &master, sizeof(int));
-
- mh.msg_controllen = cmsg->cmsg_len;
-
- if (sendmsg(pair[1], &mh, MSG_NOSIGNAL) < 0)
- _exit(EXIT_FAILURE);
-
- _exit(EXIT_SUCCESS);
- }
-
- pair[1] = safe_close(pair[1]);
-
- r = wait_for_terminate(child, &si);
- if (r < 0)
- return r;
- if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
- return -EIO;
-
- if (recvmsg(pair[0], &mh, MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) < 0)
- return -errno;
-
- for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg))
- if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
- int *fds;
- unsigned n_fds;
-
- fds = (int*) CMSG_DATA(cmsg);
- n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
-
- if (n_fds != 1) {
- close_many(fds, n_fds);
- return -EIO;
- }
-
- master = fds[0];
- }
-
- if (master < 0)
- return -EIO;
-
- return master;
-}
-