st

commit 5eef2ee3fbba84b0103b60863bfbc6ab72ff9970
parent 9f09941219345c95f647348e8764756743bbaac0
Author: Koichi Murase <myoga.murase@gmail.com>
Date:   Tue, 24 Aug 2021 06:25:05 +0900

fix a problem that the standard streams are unexpectedly closed

In the current implementation, the slave PTY (assigned to the variable
`s') is always closed after duplicating it to file descriptors of
standard streams (0, 1, and 2).  However, when the allocated slave PTY
`s' is already one of 0, 1, or 2, this causes unexpected closing of a
standard stream.  The same problem occurs when the file descriptor of
the master PTY (the variable `m') is one of 0, 1, or 2.

In this patch, the original master PTY (m) is closed before it would
be overwritten by duplicated slave PTYs.  The original slave PTY (s)
is closed only when it is not one of the stanrad streams.

Diffstat:
M
st.c
 | 
5
+++--

1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/st.c b/st.c
@@ -793,14 +793,15 @@ ttynew(const char *line, char *cmd, const char *out, char **args)
 		break;
 	case 0:
 		close(iofd);
+		close(m);
 		setsid(); /* create a new process group */
 		dup2(s, 0);
 		dup2(s, 1);
 		dup2(s, 2);
 		if (ioctl(s, TIOCSCTTY, NULL) < 0)
 			die("ioctl TIOCSCTTY failed: %s\n", strerror(errno));
-		close(s);
-		close(m);
+		if (s > 2)
+			close(s);
 #ifdef __OpenBSD__
 		if (pledge("stdio getpw proc exec", NULL) == -1)
 			die("pledge\n");