From be8ea9c41a14c8b1f8624f238b37f78043022b83 Mon Sep 17 00:00:00 2001
From: OBATA Akio <obache@wizdas.com>
Date: Sat, 29 Aug 2020 18:40:18 +0900
Subject: [PATCH] kpty: prevent to open pseudo ttys twice for openpty(3)
 platforms

Signed-off-by: OBATA Akio <obache@wizdas.com>
(cherry picked from commit 8f7371cddfa402a5561f46007985832b32383728)
---
 kdecore/kpty.cpp | 63 +++++++++++++++++++++++++++++-------------------
 1 file changed, 38 insertions(+), 25 deletions(-)

diff --git a/kdecore/kpty.cpp b/kdecore/kpty.cpp
index 7c58f74a9..1fe99275f 100644
--- a/kdecore/kpty.cpp
+++ b/kdecore/kpty.cpp
@@ -217,49 +217,60 @@ bool KPty::setPty(int pty_master)
 
 bool KPty::_attachPty(int pty_master)
 {
-  TQCString ptyName;
+  if (d->slaveFd  < 0 ) {
 
     kdDebug(175) << "KPty::_attachPty(): " << pty_master << endl;
-#if defined(HAVE_PTSNAME) && defined(HAVE_GRANTPT)
+#if defined(HAVE_PTSNAME)
     char *ptsn = ptsname(d->masterFd);
     if (ptsn) {
-        grantpt(d->masterFd);
         d->ttyName = ptsn;
     } else {
        ::close(d->masterFd);
        d->masterFd = -1;
+       return false;
     }
 #endif
 
-  struct stat st;
-  if (stat(d->ttyName.data(), &st))
-    return false; // this just cannot happen ... *cough*  Yeah right, I just
-                  // had it happen when pty #349 was allocated.  I guess
-                  // there was some sort of leak?  I only had a few open.
-  if (((st.st_uid != getuid()) ||
-       (st.st_mode & (S_IRGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH))) &&
-      !chownpty(true))
-  {
-    kdWarning(175)
-      << "KPty::_attachPty(): " << "chownpty failed for device " << ptyName << "::" << d->ttyName << endl
-      << "KPty::_attachPty(): " << "This means the communication can be eavesdropped." << endl;
-  }
+#if defined(HAVE_GRANTPT)
+    if (grantpt(d->masterFd)) {
+      return false;
+    }
+#else
+    struct stat st;
+    if (stat(d->ttyName.data(), &st))
+      return false; // this just cannot happen ... *cough*  Yeah right, I just
+                    // had it happen when pty #349 was allocated.  I guess
+                    // there was some sort of leak?  I only had a few open.
+    if (((st.st_uid != getuid()) ||
+         (st.st_mode & (S_IRGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH))) &&
+        !chownpty(true))
+    {
+      kdWarning(175)
+        << "KPty::_attachPty(): " << "chownpty failed for device " << d->ttyName << endl
+        << "KPty::_attachPty(): " << "This means the communication can be eavesdropped." << endl;
+    }
+#endif
 
 #ifdef BSD
-  revoke(d->ttyName.data());
+    revoke(d->ttyName.data());
 #endif
 
 #ifdef HAVE_UNLOCKPT
-  unlockpt(d->masterFd);
+    unlockpt(d->masterFd);
 #endif
 
-  d->slaveFd = ::open(d->ttyName.data(), O_RDWR | O_NOCTTY);
-  if (d->slaveFd < 0)
-  {
-    kdWarning(175) << "KPty::_attachPty(): " << "Can't open slave pseudo teletype" << endl;
-    ::close(d->masterFd);
-    d->masterFd = -1;
-    return false;
+    d->slaveFd = ::open(d->ttyName.data(), O_RDWR | O_NOCTTY);
+    if (d->slaveFd < 0)
+    {
+      kdWarning(175) << "KPty::_attachPty(): " << "Can't open slave pseudo teletype" << endl;
+      ::close(d->masterFd);
+      d->masterFd = -1;
+      return false;
+    }
+#ifdef HAVE_OPENPTY
+    // set screen size
+    ioctl(d->slaveFd, TIOCSWINSZ, (char *)&d->winSize);
+#endif
   }
 
 #if (defined(__svr4__) || defined(__sgi__))
@@ -294,8 +305,10 @@ bool KPty::_attachPty(int pty_master)
 
   _tcsetattr(d->slaveFd, &ttmode);
 
+#ifndef HAVE_OPENPTY
   // set screen size
   ioctl(d->slaveFd, TIOCSWINSZ, (char *)&d->winSize);
+#endif
 
   fcntl(d->masterFd, F_SETFD, FD_CLOEXEC);
   fcntl(d->slaveFd, F_SETFD, FD_CLOEXEC);