+int
+set_pty(char *pty_name)
+{
+ int fd;
+
+#if !defined(LISP_FEATURE_HPUX) && !defined(SVR4)
+ fd = open("/dev/tty", O_RDWR, 0);
+ if (fd >= 0) {
+ ioctl(fd, TIOCNOTTY, 0);
+ close(fd);
+ }
+#endif
+ if ((fd = open(pty_name, O_RDWR, 0)) == -1)
+ return (-1);
+ dup2(fd, 0);
+ set_noecho(0);
+ dup2(fd, 1);
+ dup2(fd, 2);
+ close(fd);
+ return (0);
+}
+
+#endif /* !LISP_FEATURE_OPENBSD */
+
+extern char **environ;
+int spawn(char *program, char *argv[], int sin, int sout, int serr,
+ int search, char *envp[], char *pty_name, int wait)
+{
+ pid_t pid;
+ int fd;
+ int channel[2];
+ sigset_t sset;
+
+ channel[0] = -1;
+ channel[1] = -1;
+ if (!pipe(channel)) {
+ if (-1==fcntl(channel[1], F_SETFD, FD_CLOEXEC)) {
+ close(channel[1]);
+ channel[1] = -1;
+ }
+ }
+
+ pid = fork();
+ if (pid) {
+ if ((-1 != pid) && (-1 != channel[1])) {
+ int child_errno = 0;
+ int bytes = sizeof(int);
+ int n;
+ char *p = (char*)&child_errno;
+ close(channel[1]);
+ /* Try to read child errno from channel. */
+ while ((bytes > 0) &&
+ (n = read(channel[0], p, bytes))) {
+ if (-1 == n) {
+ if (EINTR == errno) {
+ continue;
+ } else {
+ break;
+ }
+ } else {
+ bytes -= n;
+ p += n;
+ }
+ }
+ close(channel[0]);
+ if (child_errno) {
+ waitpid(pid, NULL, 0);
+ /* Our convention to tell Lisp that it was the exec that
+ * failed, not the fork. */
+ pid = -2;
+ errno = child_errno;
+ }
+ }
+ return pid;
+ }
+ close (channel[0]);
+
+ /* Put us in our own process group, but only if we need not
+ * share stdin with our parent. In the latter case we claim
+ * control of the terminal. */
+ if (sin >= 0) {
+#if defined(LISP_FEATURE_HPUX) || defined(LISP_FEATURE_OPENBSD)
+ setsid();
+#elif defined(LISP_FEATURE_DARWIN)
+ setpgid(0, getpid());
+#elif defined(SVR4) || defined(__linux__) || defined(__osf__)
+ setpgrp();