[2/2] linux ttyname_r: return link if appropriate
Commit Message
Same as previous commit for ttyname
---
sysdeps/unix/sysv/linux/ttyname_r.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
Comments
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
@@ -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. */