Re: Is a pristine shell allowed to set HOME? (fwd)

[Peter Stephenson <pws@xxxxxxx>]

Bart Schaefer wrote:
> Zsh seems to be the odd man out, here.
> 
> ---------- Forwarded message ----------
> Date: Sun, 5 Feb 2006 20:14:07 +0100
> From: Jens Schweikhardt <schweikh@xxxxxxxxxxxxxxxx>
> To: austin-group-l@xxxxxxxxxxxxx
> Subject: Is a pristine shell allowed to set HOME?
> 	# env -i /bin/sh -c set | grep ^HOME=
> 	# env -i /usr/local/bin/bash -c set | grep ^HOME=
> 	# env -i /usr/local/bin/zsh -c set|grep ^HOME=
> 	HOME=/root
> 	# env -i /usr/local/bin/ksh93 -c set|grep ^HOME=
> 	# env -i /usr/local/bin/pdksh -c set|grep ^HOME=
> 	# env -i /bin/csh -c 'echo $HOME'   # = tcsh
> 	HOME: Undefined variable.

Probably better to be compatible here... hope this doesn't break
anything, but it's a very unusual case.

Index: README
===================================================================
RCS file: /cvsroot/zsh/zsh/README,v
retrieving revision 1.23
diff -u -r1.23 README
--- README	3 Oct 2005 09:00:45 -0000	1.23
+++ README	6 Feb 2006 11:13:29 -0000
@@ -31,6 +31,9 @@
 handling of other arguments).  This appears to be the standard shell
 behaviour.
 
+The variable HOME is no longer set by the shell; it must be present
+in the environment.  It is valid for the variable to be unset.
+
 Documentation
 -------------
 
Index: Src/init.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/init.c,v
retrieving revision 1.61
diff -u -r1.61 init.c
--- Src/init.c	3 Dec 2005 00:14:06 -0000	1.61
+++ Src/init.c	6 Feb 2006 11:13:30 -0000
@@ -795,22 +795,23 @@
      * recheck the info for `USERNAME'     */
     cached_uid = getuid();
 
-    /* Get password entry and set info for `HOME' and `USERNAME' */
+    /* Get password entry and set info for `USERNAME' */
 #ifdef HAVE_GETPWUID
     if ((pswd = getpwuid(cached_uid))) {
-	home = metafy(pswd->pw_dir, -1, META_DUP);
 	cached_username = ztrdup(pswd->pw_name);
     } else
 #endif /* HAVE_GETPWUID */
 	   {
-	home = ztrdup("/");
 	cached_username = ztrdup("");
     }
 
-    /* Try a cheap test to see if we can *
-     * initialize `PWD' from `HOME'      */
-    if (ispwd(home))
-	pwd = ztrdup(home);
+    /*
+     * Try a cheap test to see if we can initialize `PWD' from `HOME'.
+     * HOME must come from the environment; we're not allowed to
+     * set it locally.
+     */
+    if ((ptr = getenv("HOME")) && ispwd(ptr))
+	pwd = ztrdup(ptr);
     else if ((ptr = zgetenv("PWD")) && (strlen(ptr) < PATH_MAX) &&
 	     (ptr = metafy(ptr, -1, META_STATIC), ispwd(ptr)))
 	pwd = ztrdup(ptr);
@@ -1105,8 +1106,11 @@
 
     queue_signals();
     if (emulation == EMULATE_SH || emulation == EMULATE_KSH ||
-	!(h = getsparam("ZDOTDIR")))
+	!(h = getsparam("ZDOTDIR"))) {
 	h = home;
+	if (!h)
+	    return;
+    }
 
     {
 	/* Let source() complain if path is too long */
Index: Src/params.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/params.c,v
retrieving revision 1.107
diff -u -r1.107 params.c
--- Src/params.c	7 Nov 2005 09:37:34 -0000	1.107
+++ Src/params.c	6 Feb 2006 11:13:31 -0000
@@ -257,7 +257,7 @@
 IPDEF2("USERNAME", username_gsu, PM_DONTIMPORT|PM_RESTRICTED),
 IPDEF2("-", dash_gsu, PM_READONLY),
 IPDEF2("histchars", histchars_gsu, PM_DONTIMPORT),
-IPDEF2("HOME", home_gsu, 0),
+IPDEF2("HOME", home_gsu, PM_UNSET),
 IPDEF2("TERM", term_gsu, 0),
 IPDEF2("WORDCHARS", wordchars_gsu, 0),
 IPDEF2("IFS", ifs_gsu, PM_DONTIMPORT),
@@ -690,9 +690,6 @@
     *envp = '\0';
     opts[ALLEXPORT] = oae;
 
-    pm = (Param) paramtab->getnode(paramtab, "HOME");
-    if (!(pm->flags & PM_EXPORTED))
-	addenv(pm, home);
     pm = (Param) paramtab->getnode(paramtab, "LOGNAME");
     if (!(pm->flags & PM_EXPORTED))
 	addenv(pm, pm->u.str);
Index: Src/subst.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/subst.c,v
retrieving revision 1.43
diff -u -r1.43 subst.c
--- Src/subst.c	1 Nov 2005 18:04:25 -0000	1.43
+++ Src/subst.c	6 Feb 2006 11:13:32 -0000
@@ -417,7 +417,7 @@
 
 	val = zstrtol(str + 1, &ptr, 10);
 	if (isend(str[1])) {   /* ~ */
-	    *namptr = dyncat(home, str + 1);
+	    *namptr = dyncat(home ? home : "", str + 1);
 	    return 1;
 	} else if (str[1] == '+' && isend(str[2])) {   /* ~+ */
 	    *namptr = dyncat(pwd, str + 2);
Index: Src/utils.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/utils.c,v
retrieving revision 1.115
diff -u -r1.115 utils.c
--- Src/utils.c	13 Jan 2006 17:13:49 -0000	1.115
+++ Src/utils.c	6 Feb 2006 11:13:34 -0000
@@ -630,8 +630,8 @@
      * whenever a node is added to or removed from the hash table, and *
      * whenever the value of $HOME changes.  (On startup, too.)        */
     if (!s) {
-	homenode.dir = home;
-	homenode.diff = strlen(home);
+	homenode.dir = home ? home : "";
+	homenode.diff = home ? strlen(home) : 0;
 	if(homenode.diff==1)
 	    homenode.diff = 0;
 	if(!finddir_full)
Index: Src/Modules/newuser.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Modules/newuser.c,v
retrieving revision 1.3
diff -u -r1.3 newuser.c
--- Src/Modules/newuser.c	10 Dec 2005 00:27:11 -0000	1.3
+++ Src/Modules/newuser.c	6 Feb 2006 11:13:34 -0000
@@ -67,8 +67,11 @@
     if (emulation != EMULATE_ZSH)
 	return 0;
 
-    if (!dotdir)
+    if (!dotdir) {
 	dotdir = home;
+	if (!dotdir)
+	    return;
+    }
 
     if (check_dotfile(dotdir, ".zshenv") == 0 ||
 	check_dotfile(dotdir, ".zprofile") == 0 ||

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070


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