The following reply was made to PR kern/36385; it has been noted by GNATS.

From: christos@zoulas.com (Christos Zoulas)
To: Michael Piotrowski <mxp@dynalabs.de>
Cc: gnats-bugs@NetBSD.org, kern-bug-people@netbsd.org,
	gnats-admin@netbsd.org, netbsd-bugs@netbsd.org
Subject: Re: kern/36385: systrace and non-existent files
Date: Fri, 25 May 2007 07:59:01 -0400

 On May 25, 12:28am, mxp@dynalabs.de (Michael Piotrowski) wrote:
 -- Subject: Re: kern/36385: systrace and non-existent files
 
 | On 2007-05-24, christos@zoulas.com (Christos Zoulas) wrote:
 | 
 | > |  Hmm, I don't see any new check-ins--which version of intercept.c would
 | > |  that be?
 | >
 | > 1.29.
 | 
 | I'm sorry, but I can't find it.
 | 
 | Looking at <http://cvsweb.netbsd.org/bsdweb.cgi/src/bin/systrace/>, I
 | only see 1.28.
 
 Something is wrong with the transfer from cvs to anoncvs.
 
 Here is the diff.
 
 christos
 
 Index: intercept.c
 ===================================================================
 RCS file: /cvsroot/src/bin/systrace/intercept.c,v
 retrieving revision 1.28
 retrieving revision 1.29
 diff -u -r1.28 -r1.29
 --- intercept.c	29 Apr 2007 20:23:35 -0000	1.28
 +++ intercept.c	24 May 2007 18:18:43 -0000	1.29
 @@ -1,4 +1,4 @@
 -/*	$NetBSD: intercept.c,v 1.28 2007/04/29 20:23:35 msaitoh Exp $	*/
 +/*	$NetBSD: intercept.c,v 1.29 2007/05/24 18:18:43 christos Exp $	*/
  /*	$OpenBSD: intercept.c,v 1.29 2002/08/28 03:30:27 itojun Exp $	*/
  /*
   * Copyright 2002 Niels Provos <provos@citi.umich.edu>
 @@ -30,7 +30,7 @@
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  #include <sys/cdefs.h>
 -__RCSID("$NetBSD: intercept.c,v 1.28 2007/04/29 20:23:35 msaitoh Exp $");
 +__RCSID("$NetBSD: intercept.c,v 1.29 2007/05/24 18:18:43 christos Exp $");
  
  #include <sys/types.h>
  #include <sys/param.h>
 @@ -1014,142 +1014,47 @@
  	(*intercept_pfreecb)(policynr, intercept_pfreearg);
  }
  
 +/* Like the libc realpath, only we succeed if the last component does
 + * not exist.
 + */
  char *
  intercept_realpath(const char *path, char *resolved)
  {
 +	char orig[MAXPATHLEN];
  	struct stat sb;
 -	int idx = 0, n, nlnk = 0, serrno = errno;
 -	const char *q;
 -	char *p, wbuf[2][MAXPATHLEN];
 -	size_t len;
 +	char *ptr;
  
 -	/*
 -	 * Build real path one by one with paying an attention to .,
 -	 * .. and symbolic link.
 -	 */
 +	if (stat(path, &sb) != -1)
 +		return realpath(path, resolved);
  
 -	/*
 -	 * `p' is where we'll put a new component with prepending
 -	 * a delimiter.
 -	 */
 -	p = resolved;
 +	if (strlcpy(orig, path, sizeof(orig)) >= sizeof(orig))
 +		goto toolong;
  
 -	if (*path == 0) {
 -		*p = 0;
 +	/* Remove trailing slashes, while keeping the last one */
 +	while ((ptr = strrchr(orig, '/')) != NULL && ptr[1] == '\0')
 +		*ptr = '\0';
 +		
 +	if (ptr == NULL) {
  		errno = ENOENT;
 -		return (NULL);
 +		return NULL;
  	}
  
 -	/* If relative path, start from current working directory. */
 -	if (*path != '/') {
 -		if (getcwd(resolved, MAXPATHLEN) == NULL) {
 -			p[0] = '.';
 -			p[1] = 0;
 -			return (NULL);
 -		}
 -		len = strlen(resolved);
 -		if (len > 1)
 -			p += len;
 -	}
 -
 -loop:
 -	/* Skip any slash. */
 -	while (*path == '/')
 -		path++;
 -
 -	if (*path == 0) {
 -		if (p == resolved)
 -			*p++ = '/';
 -		*p = 0;
 -		return (resolved);
 -	}
 -
 -	/* Find the end of this component. */
 -	q = path;
 -	do
 -		q++;
 -	while (*q != '/' && *q != 0);
 -
 -	/* Test . or .. */
 -	if (path[0] == '.') {
 -		if (q - path == 1) {
 -			path = q;
 -			goto loop;
 -		}
 -		if (path[1] == '.' && q - path == 2) {
 -			/* Trim the last component. */
 -			if (p != resolved)
 -				while (*--p != '/')
 -					;
 -			path = q;
 -			goto loop;
 -		}
 -	}
 +	/* Trim last component */
 +	*ptr++ = '\0';
  
 -	/* Append this component. */
 -	if (p - resolved + 1 + q - path + 1 > MAXPATHLEN) {
 -		errno = ENAMETOOLONG;
 -		if (p == resolved)
 -			*p++ = '/';
 -		*p = 0;
 -		return (NULL);
 -	}
 -	p[0] = '/';
 -	memcpy(&p[1], path,
 -	    /* LINTED We know q > path. */
 -	    q - path);
 -	p[1 + q - path] = 0;
 +	if (realpath(orig, resolved) == NULL)
 +		return NULL;
  
 -	/*
 -	 * If this component is a symlink, toss it and prepend link
 -	 * target to unresolved path.
 -	 */
 -	if (lstat(resolved, &sb) == -1) {
 -		/* Allow nonexistent component if this is the last one. */
 -		while (*q == '/')
 -			q++;
 -
 -		if (*q == 0  && errno == ENOENT) {
 -			errno = serrno;
 -			return (resolved);
 -		}
 +	/* Put last component back */
 +	if (strlcat(resolved, "/", MAXPATHLEN) >= MAXPATHLEN)
 +		goto toolong;
  
 -		return (NULL);
 -	}
 -	if (S_ISLNK(sb.st_mode)) {
 -		if (nlnk++ >= MAXSYMLINKS) {
 -			errno = ELOOP;
 -			return (NULL);
 -		}
 -		n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1);
 -		if (n < 0)
 -			return (NULL);
 -		if (n == 0) {
 -			errno = ENOENT;
 -			return (NULL);
 -		}
 +	if (strlcat(resolved, ptr, MAXPATHLEN) >= MAXPATHLEN)
 +		goto toolong;
  
 -		/* Append unresolved path to link target and switch to it. */
 -		if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) {
 -			errno = ENAMETOOLONG;
 -			return (NULL);
 -		}
 -		memcpy(&wbuf[idx][n], q, len + 1);
 -		path = wbuf[idx];
 -		idx ^= 1;
 -
 -		/* If absolute symlink, start from root. */
 -		if (*path == '/')
 -			p = resolved;
 -		goto loop;
 -	}
 -	if (*q == '/' && !S_ISDIR(sb.st_mode)) {
 -		errno = ENOTDIR;
 -		return (NULL);
 -	}
 +	return resolved;
  
 -	/* Advance both resolved and unresolved path. */
 -	p += 1 + q - path;
 -	path = q;
 -	goto loop;
 +toolong:
 +	errno = ENAMETOOLONG;
 +	return NULL;
  }