diff mbox

[2/2] linux ttyname_r: return link if appropriate

Message ID 20160418195349.GC30476@ubuntumail
State New, archived
Headers show

Commit Message

Serge Hallyn April 18, 2016, 7:53 p.m. UTC
Same as previous commit for ttyname
---
 sysdeps/unix/sysv/linux/ttyname_r.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Comments

Mike Frysinger April 18, 2016, 8:03 p.m. UTC | #1
On 18 Apr 2016 19:53, Serge Hallyn wrote:
> Same as previous commit for ttyname

i think it's preferable to squash it into the previous commit.
it's not like we'd merge one w/out the other.
-mike
diff mbox

Patch

diff --git a/sysdeps/unix/sysv/linux/ttyname_r.c b/sysdeps/unix/sysv/linux/ttyname_r.c
index d15bc74..e3d0c8b 100644
--- a/sysdeps/unix/sysv/linux/ttyname_r.c
+++ b/sysdeps/unix/sysv/linux/ttyname_r.c
@@ -32,6 +32,19 @@  static int getttyname_r (char *buf, size_t buflen,
 			 dev_t mydev, ino64_t myino, int save,
 			 int *dostat) internal_function;
 
+/* Return true if this is a UNIX98 pty device, as defined in
+   linux/Documentation/devices.txt */
+static int
+is_pty (struct stat64 *sb)
+{
+#ifdef _STATBUF_ST_RDEV
+  int m = major (sb->st_rdev);
+  return (136 <= m && m <= 143);
+#else
+  return false;
+#endif
+}
+
 static int
 internal_function attribute_compat_text_section
 getttyname_r (char *buf, size_t buflen, dev_t mydev, ino64_t myino,
@@ -158,6 +171,15 @@  __ttyname_r (int fd, char *buf, size_t buflen)
 #endif
 	  )
 	return 0;
+
+      /* If the link doesn't exist, then it points to a device in another
+	 namespace.  If it is a UNIX98 pty, then return the /proc/self
+	 fd, as it points to a name unreachable in our namespace */
+      if (is_pty (&st) && strlen (procname) < buflen - 1)
+        {
+	  strcpy (buf, procname);
+	  return 0;
+        }
     }
 
   /* Prepare the result buffer.  */