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To: zsh-workers@math.gatech.edu (Zsh hackers list)
Subject: Bad exec error message fix
Date: Tue, 16 Jul 1996 13:48:51 +0200
From: Peter Stephenson <pws@ifh.de>
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This fixes the following two related (and long-standing) bugs.

1) Bad error message for a command not found with an unreadable
directory in the path.

% mkdir ~/noread
% chmod 000 ~/noread
% path=(~/noread $path)               # can be anywhere in $path
% no-such-command-of-this-name
zsh: permission denied: no-such-command-of-this-name

The shell now checks on an EACCES whether the directory is executable,
using access().  I realise access() is not perfect when running with
funny uid's, but this ought to be OK for error message purposes.  (As
ENOENT is the usual error message for a command not found with paths
correctly set up, this doesn't produce a big overhead.)


2) Bad error message for a command not found with a non-directory
in the path.

% path=(~/.zshrc $path)
% nor-this-one-either
zsh: not a directory: nor-this-one-either

Here, I have simply told it to ignore ENOTDIR (not a directory) errors
in the same way as it ignores ENOENT (file not found) when searching
for a command to execute.


Does anyone know of other related errors?

Unfortunately I can't test this under working conditions as I'd like
since the new rules for { and [[ break the initialisation scripts
here.  Hmmm.

*** Src/exec.c.perm	Mon Jul 15 02:32:31 1996
--- Src/exec.c	Tue Jul 16 13:40:28 1996
***************
*** 242,247 ****
--- 242,261 ----
  
  #define MAXCMDLEN (PATH_MAX*4)
  
+ /* test whether we really want to believe the error number */
+ 
+ /**/
+ int
+ isgooderr(int e, char *dir)
+ {
+     /*
+      * Maybe the directory was unreadable, or maybe it wasn't
+      * even a directory. 
+      */
+     return ((e != EACCES || !access(dir, X_OK)) &&
+ 	    e != ENOENT && e != ENOTDIR); 
+ }
+ 
  /* execute an external command */
  
  /**/
***************
*** 304,310 ****
  	}
  
      if (cn) {
! 	char nn[PATH_MAX];
  
  	if (cn->flags & HASHED)
  	    strcpy(nn, cn->u.cmd);
--- 318,324 ----
  	}
  
      if (cn) {
! 	char nn[PATH_MAX], *dptr;
  
  	if (cn->flags & HASHED)
  	    strcpy(nn, cn->u.cmd);
***************
*** 312,318 ****
  	    for (pp = path; pp < cn->u.name; pp++)
  		if (**pp == '.' && (*pp)[1] == '\0') {
  		    ee = zexecve(arg0, argv);
! 		    if (ee != ENOENT)
  			eno = ee;
  		} else if (**pp != '/') {
  		    z = buf;
--- 326,332 ----
  	    for (pp = path; pp < cn->u.name; pp++)
  		if (**pp == '.' && (*pp)[1] == '\0') {
  		    ee = zexecve(arg0, argv);
! 		    if (isgooderr(ee, *pp))
  			eno = ee;
  		} else if (**pp != '/') {
  		    z = buf;
***************
*** 320,326 ****
  		    *z++ = '/';
  		    strcpy(z, arg0);
  		    ee = zexecve(buf, argv);
! 		    if (ee != ENOENT)
  			eno = ee;
  		}
  	    strcpy(nn, cn->u.name ? *(cn->u.name) : "");
--- 334,340 ----
  		    *z++ = '/';
  		    strcpy(z, arg0);
  		    ee = zexecve(buf, argv);
! 		    if (isgooderr(ee, *pp))
  			eno = ee;
  		}
  	    strcpy(nn, cn->u.name ? *(cn->u.name) : "");
***************
*** 329,341 ****
  	}
  	ee = zexecve(nn, argv);
  
! 	if (ee != ENOENT)
  	    eno = ee;
      }
      for (pp = path; *pp; pp++)
  	if ((*pp)[0] == '.' && !(*pp)[1]) {
  	    ee = zexecve(arg0, argv);
! 	    if (ee != ENOENT)
  		eno = ee;
  	} else {
  	    z = buf;
--- 343,357 ----
  	}
  	ee = zexecve(nn, argv);
  
! 	if ((dptr = strrchr(nn, '/')))
! 	    *dptr = '\0';
! 	if (isgooderr(ee, *nn ? nn : "/"))
  	    eno = ee;
      }
      for (pp = path; *pp; pp++)
  	if ((*pp)[0] == '.' && !(*pp)[1]) {
  	    ee = zexecve(arg0, argv);
! 	    if (isgooderr(ee, *pp))
  		eno = ee;
  	} else {
  	    z = buf;
***************
*** 343,349 ****
  	    *z++ = '/';
  	    strcpy(z, arg0);
  	    ee = zexecve(buf, argv);
! 	    if (ee != ENOENT)
  		eno = ee;
  	}
      if (eno)
--- 359,365 ----
  	    *z++ = '/';
  	    strcpy(z, arg0);
  	    ee = zexecve(buf, argv);
! 	    if (isgooderr(ee, *pp))
  		eno = ee;
  	}
      if (eno)

-- 
Peter Stephenson <pws@ifh.de>       Tel: +49 33762 77366
WWW:  http://www.ifh.de/~pws/       Fax: +49 33762 77330
Deutches Electronen-Synchrotron --- Institut fuer Hochenergiephysik Zeuthen
DESY-IfH, 15735 Zeuthen, Germany.