+ /* Unix98 standardized grantpt, unlockpt, and ptsname, but not the
+ functions required to open a master pty in the first place :-(
+
+ Modern Unix systems all seems to have convenience methods to open
+ a master pty fd in one function call, but there is little
+ agreement on how to do it.
+
+ allocate_pty() tries all the different known easy ways of opening
+ a pty. In case of failure, we resort to the old BSD-style pty
+ grovelling code in allocate_pty_the_old_fashioned_way(). */
+#ifndef FORCE_ALLOCATE_PTY_THE_OLD_FASHIONED_WAY
+ int master_fd = -1;
+ const char *slave_name = NULL;
+ const char *clone = NULL;
+ static const char * const clones[] = /* Different pty master clone devices */
+ {
+ "/dev/ptmx", /* Various systems */
+ "/dev/ptm/clone", /* HPUX */
+ "/dev/ptc", /* AIX */
+ "/dev/ptmx_bsd" /* Tru64 */
+ };
+
+#ifdef HAVE_GETPT /* glibc */
+ master_fd = getpt ();
+ if (master_fd >= 0)
+ goto have_master;
+#endif /* HAVE_GETPT */
+
+
+#if defined(HAVE_OPENPTY) /* BSD, Tru64, glibc */
+ {
+ int slave_fd = -1;
+ int rc;
+ EMACS_BLOCK_SIGNAL (SIGCHLD);
+ rc = openpty (&master_fd, &slave_fd, NULL, NULL, NULL);
+ EMACS_UNBLOCK_SIGNAL (SIGCHLD);
+ if (rc == 0)
+ {
+ slave_name = ttyname (slave_fd);
+ close (slave_fd);
+ goto have_slave_name;
+ }
+ else
+ {
+ if (master_fd >= 0)
+ close (master_fd);
+ if (slave_fd >= 0)
+ close (slave_fd);
+ }
+ }
+#endif /* HAVE_OPENPTY */
+
+#if defined(HAVE__GETPTY) && defined (O_NDELAY) /* SGI */
+ master_fd = -1;
+ EMACS_BLOCK_SIGNAL (SIGCHLD);
+ slave_name = _getpty (&master_fd, O_RDWR | O_NDELAY, 0600, 0);
+ EMACS_UNBLOCK_SIGNAL (SIGCHLD);
+ if (master_fd >= 0 && slave_name != NULL)
+ goto have_slave_name;
+#endif /* HAVE__GETPTY */
+
+ /* Master clone devices are available on most systems */
+ {
+ int i;
+ for (i = 0; i < countof (clones); i++)
+ {
+ clone = clones[i];
+ master_fd = open (clone, O_RDWR | O_NONBLOCK | OPEN_BINARY, 0);
+ if (master_fd >= 0)
+ goto have_master;
+ }
+ clone = NULL;
+ }
+
+ goto lose;
+
+ have_master:
+
+#if defined (HAVE_PTSNAME)
+ slave_name = ptsname (master_fd);
+ if (slave_name)
+ goto have_slave_name;
+#endif
+
+ /* AIX docs say to use ttyname, not ptsname, to get slave_name */
+ if (clone
+ && !strcmp (clone, "/dev/ptc")
+ && (slave_name = ttyname (master_fd)) != NULL)
+ goto have_slave_name;
+
+ goto lose;
+
+ have_slave_name:
+ strncpy (pty_name, slave_name, sizeof (pty_name));
+ pty_name[sizeof (pty_name) - 1] = '\0';
+ setup_pty (master_fd);
+
+ /* We jump through some hoops to frob the pty.
+ It's not obvious that checking the return code here is useful. */
+
+ /* "The grantpt() function will fail if it is unable to successfully
+ invoke the setuid root program. It may also fail if the
+ application has installed a signal handler to catch SIGCHLD
+ signals." */
+#if defined (HAVE_GRANTPT) || defined (HAVE_UNLOCKPT)
+ EMACS_BLOCK_SIGNAL (SIGCHLD);
+
+#if defined (HAVE_GRANTPT)
+ grantpt (master_fd);
+#ifdef HPUX
+ /* grantpt() behavior on some versions of HP-UX differs from what's
+ specified in the man page: the group of the slave PTY is set to
+ the user's primary group, and we fix that. */
+ {
+ struct group *tty_group = getgrnam ("tty");
+ if (tty_group != NULL)
+ chown (pty_name, (uid_t) -1, tty_group->gr_gid);
+ }
+#endif /* HPUX has broken grantpt() */
+#endif /* HAVE_GRANTPT */
+
+#if defined (HAVE_UNLOCKPT)
+ unlockpt (master_fd);
+#endif
+
+ EMACS_UNBLOCK_SIGNAL (SIGCHLD);
+#endif /* HAVE_GRANTPT || HAVE_UNLOCKPT */
+
+ return master_fd;
+
+ lose:
+ if (master_fd >= 0)
+ close (master_fd);
+#endif /* ndef FORCE_ALLOCATE_PTY_THE_OLD_FASHIONED_WAY */
+ return allocate_pty_the_old_fashioned_way ();
+}
+
+/* This function tries to allocate a pty by iterating through file
+ pairs with names like /dev/ptyp1 and /dev/ttyp1. */
+static int
+allocate_pty_the_old_fashioned_way (void)
+{
projects / chise / xemacs-chise.git.1 / blobdiff