git: 40860e6bf222 - stable/13 - snp(4): properly report detached/revoked ttys

The branch stable/13 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=40860e6bf2221efb3840b380d6b5d6f3f768a633

commit 40860e6bf2221efb3840b380d6b5d6f3f768a633
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2022-09-24 20:23:31 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2022-10-02 00:51:47 +0000

    snp(4): properly report detached/revoked ttys
    
    PR:     257964
    
    (cherry picked from commit bb4be76cf358246ef04ea8a67f38ff2a25b6c580)
---
 share/man/man4/snp.4 | 8 ++------
 sys/dev/snp/snp.c    | 7 +++++--
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/share/man/man4/snp.4 b/share/man/man4/snp.4
index ce0ef66c5721..524e779ce081 100644
--- a/share/man/man4/snp.4
+++ b/share/man/man4/snp.4
@@ -1,7 +1,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 5, 2008
+.Dd September 24, 2022
 .Dt SNP 4
 .Os
 .Sh NAME
@@ -58,8 +58,6 @@ ioctl returns a positive value equal to the number of characters
 in a read buffer.
 Special values defined are:
 .Bl -tag -width ".Dv SNP_TTYCLOSE"
-.It Dv SNP_OFLOW
-device overflow occurred, device detached.
 .It Dv SNP_TTYCLOSE
 tty not attached.
 .It Dv SNP_DETACH
@@ -92,8 +90,6 @@ were based on code written by
 .Sh BUGS
 This version of
 .Nm
-does not return proper error codes when calling
-.Dv FIONREAD .
-It also does not allow
+does not allow
 .Dv SNPSTTY
 to detach itself from the TTY.
diff --git a/sys/dev/snp/snp.c b/sys/dev/snp/snp.c
index 64e2d0f64537..3bcd2263809b 100644
--- a/sys/dev/snp/snp.c
+++ b/sys/dev/snp/snp.c
@@ -289,10 +289,13 @@ snp_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags,
 		tp = ss->snp_tty;
 		if (tp != NULL) {
 			tty_lock(tp);
-			*(int *)data = ttyoutq_bytesused(&ss->snp_outq);
+			if (tty_gone(tp))
+				*(int *)data = SNP_TTYCLOSE;
+			else
+				*(int *)data = ttyoutq_bytesused(&ss->snp_outq);
 			tty_unlock(tp);
 		} else {
-			*(int *)data = 0;
+			*(int *)data = SNP_DETACH;
 		}
 		return (0);
 	default: