MFH

Sponsored by:	The FreeBSD Foundation

2 files changed, 41 insertions, 13 deletions

diff --git a/bin/sh/redir.c b/bin/sh/redir.c
index 95d3238..0a7aa96 100644
--- a/bin/sh/redir.c
+++ b/bin/sh/redir.c
@@ -70,6 +70,7 @@ struct redirtab {
 	struct redirtab *next;
 	int renamed[10];
 	int fd0_redirected;
+	unsigned int empty_redirs;
 };
 
 
@@ -82,6 +83,9 @@ static struct redirtab *redirlist;
 */
 static int fd0_redirected = 0;
 
+/* Number of redirtabs that have not been allocated. */
+static unsigned int empty_redirs = 0;
+
 static void openredirect(union node *, char[10 ]);
 static int openhere(union node *);
 
@@ -115,12 +119,17 @@ redirect(union node *redir, int flags)
 		memory[i] = 0;
 	memory[1] = flags & REDIR_BACKQ;
 	if (flags & REDIR_PUSH) {
-		sv = ckmalloc(sizeof (struct redirtab));
-		for (i = 0 ; i < 10 ; i++)
-			sv->renamed[i] = EMPTY;
-		sv->fd0_redirected = fd0_redirected;
-		sv->next = redirlist;
-		redirlist = sv;
+		empty_redirs++;
+		if (redir != NULL) {
+			sv = ckmalloc(sizeof (struct redirtab));
+			for (i = 0 ; i < 10 ; i++)
+				sv->renamed[i] = EMPTY;
+			sv->fd0_redirected = fd0_redirected;
+			sv->empty_redirs = empty_redirs - 1;
+			sv->next = redirlist;
+			redirlist = sv;
+			empty_redirs = 0;
+		}
 	}
 	for (n = redir ; n ; n = n->nfile.next) {
 		fd = n->nfile.fd;
@@ -303,6 +312,12 @@ popredir(void)
 	struct redirtab *rp = redirlist;
 	int i;
 
+	INTOFF;
+	if (empty_redirs > 0) {
+		empty_redirs--;
+		INTON;
+		return;
+	}
 	for (i = 0 ; i < 10 ; i++) {
 		if (rp->renamed[i] != EMPTY) {
 			if (rp->renamed[i] >= 0) {
@@ -313,8 +328,8 @@ popredir(void)
 			}
 		}
 	}
-	INTOFF;
 	fd0_redirected = rp->fd0_redirected;
+	empty_redirs = rp->empty_redirs;
 	redirlist = rp->next;
 	ckfree(rp);
 	INTON;
diff --git a/bin/sh/sh.1 b/bin/sh/sh.1
index 14ae898..9406779 100644
--- a/bin/sh/sh.1
+++ b/bin/sh/sh.1
@@ -32,7 +32,7 @@
 .\"	from: @(#)sh.1	8.6 (Berkeley) 5/4/95
 .\" $FreeBSD$
 .\"
-.Dd August 29, 2015
+.Dd January 30, 2016
 .Dt SH 1
 .Os
 .Sh NAME
@@ -1952,13 +1952,20 @@ Execute the specified built-in command,
 This is useful when the user wishes to override a shell function
 with the same name as a built-in command.
 .It Ic cd Oo Fl L | P Oc Oo Fl e Oc Op Ar directory
+.It Ic cd Fl
 Switch to the specified
 .Ar directory ,
-or to the directory specified in the
+to the directory specified in the
 .Va HOME
 environment variable if no
 .Ar directory
-is specified.
+is specified or
+to the directory specified in the
+.Va OLDPWD
+environment variable if
+.Ar directory
+is
+.Fl .
 If
 .Ar directory
 does not begin with
@@ -1982,10 +1989,12 @@ the
 .Ic cd
 command will print out the name of the directory
 that it actually switched to
-if this is different from the name that the user gave.
-These may be different either because the
+if the
 .Va CDPATH
-mechanism was used or because a symbolic link was crossed.
+mechanism was used or if
+.Ar directory
+was
+.Fl .
 .Pp
 If the
 .Fl P
@@ -2774,6 +2783,10 @@ Initialization file for interactive shells.
 Locale settings.
 These are inherited by children of the shell,
 and is used in a limited manner by the shell itself.
+.It Ev OLDPWD
+The previous current directory.
+This is used and updated by
+.Ic cd .
 .It Ev PWD
 An absolute pathname for the current directory,
 possibly containing symbolic links.