From: Alan Cox <alan@linux.intel.com>
Date: Thu, 21 May 2015 22:58:49 +0000 (+0100)
Subject: tty: handle close better
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=ad59a7240df134177c574bda1ffe9f7794eb806c;p=FUZIX.git

tty: handle close better
---

diff --git a/Kernel/include/tty.h b/Kernel/include/tty.h
index 1a87684d..47020180 100644
--- a/Kernel/include/tty.h
+++ b/Kernel/include/tty.h
@@ -151,10 +151,10 @@ struct termios {
    the data indexed off a single register */
 struct tty {
     /* Put flag first: makes it cheaper when short of registers */
-    uint8_t flag;		/* Use uint8 pad - makes the whole struct
+    uint8_t flag;		/* make the whole struct
                                    24 byte - a nice number for CPUs with no 
                                    multiplier */
-    uint8_t pad0;
+    uint8_t users;
 #define TTYF_STOP	1
 #define TTYF_DISCARD	2
 #define TTYF_DEAD	4
diff --git a/Kernel/tty.c b/Kernel/tty.c
index 5ee924f4..61e9ab7a 100644
--- a/Kernel/tty.c
+++ b/Kernel/tty.c
@@ -172,6 +172,10 @@ int tty_open(uint8_t minor, uint16_t flag)
 		udata.u_ptab->p_tty = minor;
 		t->pgrp = udata.u_ptab->p_pgrp;
 	}
+	if (t->users) {
+	        t->users++;
+	        return 0;
+        }
 	tty_setup(minor);
 	if ((t->termios.c_cflag & CLOCAL) || (flag & O_NDELAY))
 	        return 0;
@@ -187,18 +191,21 @@ int tty_open(uint8_t minor, uint16_t flag)
                 t->flag &= ~TTYF_DEAD;
                 return -1;
         }
+        t->users++;
         return 0;
 }
 
 int tty_close(uint8_t minor)
 {
+        struct tty *t = &ttydata[minor];
+        if (--t->users)
+                return 0;
 	/* If we are closing the controlling tty, make note */
-	if (minor == udata.u_ptab->p_tty) {
+	if (minor == udata.u_ptab->p_tty)
 		udata.u_ptab->p_tty = 0;
-		ttydata[minor].pgrp = 0;
-        }
+	t->pgrp = 0;
         /* If we were hung up then the last opener has gone away */
-        ttydata[minor].flag &= ~TTYF_DEAD;
+        t->flag &= ~TTYF_DEAD;
 	return (0);
 }