From feeb62d15f61a52788175a9f4e3ecc0cdca71d87 Mon Sep 17 00:00:00 2001
From: Johnothan King <johnothanking@protonmail.com>
Date: Sun, 26 Dec 2021 09:03:51 -0800
Subject: [PATCH] sh_close(): Set errno to EBADF for invalid file descriptors
 (#399)

The sh_close() function fails to set errno to EBADF when passed a
negative (invalid) file descriptor. This commit fixes the issue
by setting errno if the file descriptor is a negative value
(backported from ksh93v- 2012-08-24).
---
 src/cmd/ksh93/sh/io.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/cmd/ksh93/sh/io.c b/src/cmd/ksh93/sh/io.c
index 7c57253d1..ef5fc05ef 100644
--- a/src/cmd/ksh93/sh/io.c
+++ b/src/cmd/ksh93/sh/io.c
@@ -708,7 +708,10 @@ int sh_close(register int fd)
 	register Sfio_t *sp;
 	register int r = 0;
 	if(fd<0)
+	{
+		errno = EBADF;
 		return(-1);
+	}
 	if(fd >= shp->gd->lim.open_max)
 		sh_iovalidfd(shp,fd);
 	if(!(sp=shp->sftable[fd]) || sfclose(sp) < 0)