Module Name: src
Committed By: kre
Date: Mon Jan 31 16:54:28 UTC 2022
Modified Files:
src/bin/sh: cd.c histedit.c
Log Message:
Add some comments explaining accesses to the environment via
getenv()/setenv()/unsetenv() which manipulate the envornoment
the shell was passed at entry.
These are a little odd in sh as that environment is copied into
the shell's internal variable data struct at shell startup, and
normally never accessed after that - in builtin commands (test.
printf, ...) getenv() is #defined to become an internal sh lookup
function instead, so even those never use the startup environment).
NFCI
To generate a diff of this commit:
cvs rdiff -u -r1.52 -r1.53 src/bin/sh/cd.c
cvs rdiff -u -r1.57 -r1.58 src/bin/sh/histedit.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/bin/sh/cd.c
diff -u src/bin/sh/cd.c:1.52 src/bin/sh/cd.c:1.53
--- src/bin/sh/cd.c:1.52 Tue Nov 16 16:57:15 2021
+++ src/bin/sh/cd.c Mon Jan 31 16:54:28 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: cd.c,v 1.52 2021/11/16 16:57:15 kre Exp $ */
+/* $NetBSD: cd.c,v 1.53 2022/01/31 16:54:28 kre Exp $ */
/*-
* Copyright (c) 1991, 1993
@@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95";
#else
-__RCSID("$NetBSD: cd.c,v 1.52 2021/11/16 16:57:15 kre Exp $");
+__RCSID("$NetBSD: cd.c,v 1.53 2022/01/31 16:54:28 kre Exp $");
#endif
#endif /* not lint */
@@ -404,6 +404,20 @@ getpwd(int noerror)
return;
if (first) {
+ /*
+ * Note that this happens via the call from initpwd()
+ * just above, which is called early from main() during
+ * sh startup, so fetching PWD from the entry environment
+ * (which is what getenv() does) is acceptable. Here we
+ * could use normal sh var lookup functions instead, as
+ * the arriving environment has already been imported before
+ * we get here, but it makes little difference.
+ *
+ * XXX What would be better perhaps would be to move all of
+ * this into initpwd() instead of here, so we could get rid of
+ * this "first" static - that function is only ever called once.
+ * XXX Some other day.
+ */
first = 0;
pwd = getenv("PWD");
if (is_curdir(pwd)) {
Index: src/bin/sh/histedit.c
diff -u src/bin/sh/histedit.c:1.57 src/bin/sh/histedit.c:1.58
--- src/bin/sh/histedit.c:1.57 Tue Sep 14 15:04:09 2021
+++ src/bin/sh/histedit.c Mon Jan 31 16:54:28 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: histedit.c,v 1.57 2021/09/14 15:04:09 christos Exp $ */
+/* $NetBSD: histedit.c,v 1.58 2022/01/31 16:54:28 kre Exp $ */
/*-
* Copyright (c) 1993
@@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)histedit.c 8.2 (Berkeley) 5/4/95";
#else
-__RCSID("$NetBSD: histedit.c,v 1.57 2021/09/14 15:04:09 christos Exp $");
+__RCSID("$NetBSD: histedit.c,v 1.58 2022/01/31 16:54:28 kre Exp $");
#endif
#endif /* not lint */
@@ -129,6 +129,23 @@ histedit(void)
if (tracefile)
el_err = tracefile;
#endif
+ /*
+ * This odd piece of code doesn't affect the shell
+ * at all, the environment modified here is the
+ * stuff accessed via "environ" (the incoming
+ * envoironment to the shell) which is only ever
+ * touched at sh startup time (long before we get
+ * here) and ignored thereafter.
+ *
+ * But libedit calls getenv() to discover TERM
+ * and that searches the "environ" environment,
+ * not the shell's internal variable data struct,
+ * so we need to make sure that TERM in there is
+ * correct.
+ *
+ * This sequence copies TERM from the shell into
+ * the old "environ" environment.
+ */
term = lookupvar("TERM");
if (term)
setenv("TERM", term, 1);
