slattach: add support for /dev/ptmx [Bug:3467521]

diff --git a/slattach.c b/slattach.c
index 0f4ccd6..2b7dde2 100644 (file)
--- a/slattach.c
+++ b/slattach.c
@@ -62,10 +62,13 @@
 #include "util.h"
 
 #ifndef _PATH_LOCKD
-#define _PATH_LOCKD            "/var/lock"             /* lock files   */
+#define _PATH_LOCKD    "/var/lock"             /* lock files   */
 #endif
 #ifndef _UID_UUCP
-#define _UID_UUCP              "uucp"                  /* owns locks   */
+#define _UID_UUCP      "uucp"                  /* owns locks   */
+#endif
+#ifndef _PATH_DEVPTMX
+#define _PATH_DEVPTMX  "/dev/ptmx"             /* pseudo-terminal master */
 #endif
 
 
@@ -108,6 +111,7 @@ struct termios      tty_saved,              /* saved TTY device state       */
 int            tty_sdisc,              /* saved TTY line discipline    */
                tty_ldisc,              /* current TTY line discipline  */
                tty_fd = -1;            /* TTY file descriptor          */
+char *         path_pts = NULL;        /* slave pseudo-terminal device */
 int            opt_c = 0;              /* "command" to run at exit     */
 int            opt_e = 0;              /* "activate only" flag         */
 int            opt_h = 0;              /* "hangup" on carrier loss     */
@@ -492,7 +496,28 @@ tty_open(char *name, const char *speed)
                return(-errno);
        }
        tty_fd = fd;
-       if (opt_d) printf("slattach: tty_open: %s (fd=%d) ", path_open, fd);
+       if (opt_d) printf("slattach: tty_open: %s (fd=%d)\n", path_open, fd);
+       if (!strcmp(path_open, _PATH_DEVPTMX)) {
+               if (opt_d) printf("slattach: tty_open: trying to grantpt and unlockpt\n");
+               if (grantpt(fd) < 0) {
+                   if (opt_q == 0) fprintf(stderr,
+                           "slattach: tty_open: grantpt: %s\n", strerror(errno));
+                   return(-errno);
+               }
+               if (unlockpt(fd) < 0) {
+                   if (opt_q == 0) fprintf(stderr,
+                           "slattach: tty_open: unlockpt: %s\n", strerror(errno));
+                   return(-errno);
+               }
+               path_pts = ptsname(fd);
+               if (path_pts == NULL) {
+                   if (opt_q == 0) fprintf(stderr,
+                           "slattach: tty_open: ptsname: %s\n", strerror(errno));
+                   return(-errno);
+               }
+               if (opt_d) printf("slattach: tty_open: %s: slave pseudo-terminal is %s\n",
+                                 path_open, path_pts);
+       }
   } else {
        tty_fd = 0;
   }
@@ -707,6 +732,7 @@ main(int argc, char *argv[])
         if (tty_get_name(buff)) { return(3); }
        printf(_("%s started"), proto);
        if (path_dev != NULL) printf(_(" on %s"), path_dev);
+       if (path_pts != NULL) printf(_(" ptsname %s"), path_pts);
        printf(_(" interface %s\n"), buff);
   }