Re: Running 'type' causes false positive hashed command completion

[Daniel Shahaf <d.s@daniel.shahaf.name>]

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Bart Schaefer wrote on Thu, Aug 25, 2016 at 09:59:00 -0700:
> On Aug 24,  8:58pm, Daniel Shahaf wrote:
> } Subject: Running 'type' causes false positive hashed command completion
> }
> } $ zsh -f
> } % cd $(mtemp -d)
> } % touch sudofoo; chmod +x $_
> } % ./sudo<TAB>
> } <becomes>
> } % ./sudofoo <^C>
> } % type -w ./sudo
> } ./sudo: none
> } % ./sudo<TAB>
> } ./sudo    sudofoo*
> } 
> } That's wrong because ./sudo does not exist.
> 
> This seems pretty obvious:
> 
> 
> diff --git a/Src/exec.c b/Src/exec.c
> index ea9214d..9b24d38 100644
> --- a/Src/exec.c
> +++ b/Src/exec.c
> @@ -772,7 +772,7 @@ findcmd(char *arg0, int docopy)
> -    if (!cn && isset(HASHCMDS))
> +    if (!cn && isset(HASHCMDS) && !isrelative(arg0))
>  	cn = hashcmd(arg0, path);
> 
> Can anyone think of a valid case which that breaks?  The doc (under the
> PATH_DIRS option) even says "Commands explicitly beginning with `/', `./'
> or `../' are not subject to the path search."

I've just noticed another bug (predates this patch):

% setopt pathdirs
% ./pwd 
zsh: no such file or directory: ./pwd
% type ./pwd          
./pwd is /bin/./pwd

That's wrong, 'type' should have returned 'none'.

Patch attached.

Cheers,

Daniel

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>From d69ba249faeab0e6edb95062482d4f59fde01039 Mon Sep 17 00:00:00 2001
From: Daniel Shahaf <d.s@daniel.shahaf.name>
Date: Fri, 11 Nov 2016 02:25:21 +0000
Subject: [PATCH] whence: Honor PATH_DIRS option for arguments that start with
 './' or '../'.

While here, add some docstrings.
---
 Src/exec.c           | 23 ++++++++++++++++-------
 Test/E01options.ztst |  4 ++++
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/Src/exec.c b/Src/exec.c
index a01a633..ad80dd0 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -806,14 +806,13 @@ findcmd(char *arg0, int docopy, int default_path)
 	cn = hashcmd(arg0, path);
     if ((int) strlen(arg0) > PATH_MAX)
 	return NULL;
-    for (s = arg0; *s; s++)
-	if (*s == '/') {
-	    RET_IF_COM(arg0);
-	    if (arg0 == s || unset(PATHDIRS)) {
-		return NULL;
-	    }
-	    break;
+    if ((s = strchr(arg0, '/'))) {
+	RET_IF_COM(arg0);
+	if (arg0 == s || unset(PATHDIRS) || !strncmp(arg0, "./", 2) ||
+	    !strncmp(arg0, "../", 3)) {
+	    return NULL;
 	}
+    }
     if (cn) {
 	char nn[PATH_MAX];
 
@@ -848,6 +847,11 @@ findcmd(char *arg0, int docopy, int default_path)
     return NULL;
 }
 
+/*
+ * Return TRUE if the given path denotes an executable regular file, or a
+ * symlink to one.
+ */
+
 /**/
 int
 iscom(char *s)
@@ -877,6 +881,11 @@ isreallycom(Cmdnam cn)
     return iscom(fullnam);
 }
 
+/*
+ * Return TRUE if the given path contains a dot or dot-dot component
+ * and does not start with a slash.
+ */
+
 /**/
 int
 isrelative(char *s)
diff --git a/Test/E01options.ztst b/Test/E01options.ztst
index 40e96af..45df9f5 100644
--- a/Test/E01options.ztst
+++ b/Test/E01options.ztst
@@ -784,6 +784,10 @@
 >unsetting option...
 ?(eval):14: no such file or directory: pathtestdir/findme
 
+  (setopt pathdirs; path+=( /usr/bin ); type ./env)
+1:whence honours PATH_DIRS option
+>./env not found
+
   setopt posixbuiltins
   PATH= command -v print
   PATH= command -V print