Linux: Require properly configured /dev/pts for PTYs

Current systems do not have BSD terminals, so the fallback code in
posix_openpt/getpt does not do anything.  Also remove the file system
check for /dev/pts.  Current systems always have a devpts file system
mounted there if /dev/ptmx exists.

grantpt is now essentially a no-op.  It only verifies that the
argument is a ptmx-descriptor.  Therefore, this change indirectly
addresses bug 24941.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

1 files changed, 3 insertions, 64 deletions

diff --git a/sysdeps/unix/sysv/linux/getpt.c b/sysdeps/unix/sysv/linux/getpt.c
index 1803b232c9..3cc745e11a 100644
--- a/sysdeps/unix/sysv/linux/getpt.c
+++ b/sysdeps/unix/sysv/linux/getpt.c
@@ -16,69 +16,18 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
 #include <fcntl.h>
-#include <stdlib.h>
 #include <unistd.h>
 #include <paths.h>
-#include <sys/statfs.h>
-
-#include "linux_fsinfo.h"
 
 /* Path to the master pseudo terminal cloning device.  */
 #define _PATH_DEVPTMX _PATH_DEV "ptmx"
-/* Directory containing the UNIX98 pseudo terminals.  */
-#define _PATH_DEVPTS _PATH_DEV "pts"
-
-/* Prototype for function that opens BSD-style master pseudo-terminals.  */
-extern int __bsd_getpt (void) attribute_hidden;
 
 /* Open a master pseudo terminal and return its file descriptor.  */
 int
 __posix_openpt (int oflag)
 {
-  static int have_no_dev_ptmx;
-  int fd;
-
-  if (!have_no_dev_ptmx)
-    {
-      fd = __open (_PATH_DEVPTMX, oflag);
-      if (fd != -1)
-	{
-	  struct statfs fsbuf;
-	  static int devpts_mounted;
-
-	  /* Check that the /dev/pts filesystem is mounted
-	     or if /dev is a devfs filesystem (this implies /dev/pts).  */
-	  if (devpts_mounted
-	      || (__statfs (_PATH_DEVPTS, &fsbuf) == 0
-		  && fsbuf.f_type == DEVPTS_SUPER_MAGIC)
-	      || (__statfs (_PATH_DEV, &fsbuf) == 0
-		  && fsbuf.f_type == DEVFS_SUPER_MAGIC))
-	    {
-	      /* Everything is ok.  */
-	      devpts_mounted = 1;
-	      return fd;
-	    }
-
-	  /* If /dev/pts is not mounted then the UNIX98 pseudo terminals
-	     are not usable.  */
-	  __close (fd);
-	  have_no_dev_ptmx = 1;
-	  __set_errno (ENOENT);
-	}
-      else
-	{
-	  if (errno == ENOENT || errno == ENODEV)
-	    have_no_dev_ptmx = 1;
-	  else
-	    return -1;
-	}
-    }
-  else
-    __set_errno (ENOENT);
-
-  return -1;
+  return __open (_PATH_DEVPTMX, oflag);
 }
 weak_alias (__posix_openpt, posix_openpt)
 
@@ -86,16 +35,6 @@ weak_alias (__posix_openpt, posix_openpt)
 int
 __getpt (void)
 {
-  int fd = __posix_openpt (O_RDWR);
-  if (fd == -1)
-    fd = __bsd_getpt ();
-  return fd;
+  return __posix_openpt (O_RDWR);
 }
-
-
-#define PTYNAME1 "pqrstuvwxyzabcde";
-#define PTYNAME2 "0123456789abcdef";
-
-#define __getpt __bsd_getpt
-#define HAVE_POSIX_OPENPT
-#include <sysdeps/unix/bsd/getpt.c>
+weak_alias (__getpt, getpt)