configure.in: Add check for lstat.

	* configure.in: Add check for lstat.
	* configure, config.in: Regenerate.
	* cppinit.c (append_include_chain): Make empty path ".".
        * cpplib.c (do_line): Don't simplify #line paths.
        * cppfiles.c (remove_component_p): New function.
	(find_or_create_entry): Acknowledge stat () errors during
	path simplification.
	(handle_missing_header): Don't simplify paths.
        (_cpp_simplify_pathname): Don't simplify VMS paths.  Return
        the empty path untouched.  Don't leave a trailing '/'.

From-SVN: r41148

gcc/ChangeLog

+2001-04-06  Neil Booth  <neil@daikokuya.demon.co.uk>
+
+	* configure.in: Add check for lstat.
+	* configure, config.in: Regenerate.
+	* cppinit.c (append_include_chain): Make empty path ".".
+        * cpplib.c (do_line): Don't simplify #line paths.
+        * cppfiles.c (remove_component_p): New function.
+	(find_or_create_entry): Acknowledge stat () errors during
+	path simplification.
+	(handle_missing_header): Don't simplify paths.
+        (_cpp_simplify_pathname): Don't simplify VMS paths.  Return
+        the empty path untouched.  Don't leave a trailing '/'.
+
 2001-04-06  Benjamin Kosnik  <bkoz@redhat.com>
 	
 	* cppdefault.c (GPLUSPLUS_BACKWARD_INCLUDE_DIR): Add.

gcc/config.in

@@ -134,6 +134,9 @@
 /* Define if you have the kill function.  */
 #undef HAVE_KILL
 
+/* Define if you have the lstat function.  */
+#undef HAVE_LSTAT
+
 /* Define if you have the munmap function.  */
 #undef HAVE_MUNMAP
 

gcc/configure

@@ -3102,7 +3102,7 @@ fi
 for ac_func in strtoul bsearch popen \
 	strchr strrchr kill getrlimit setrlimit atoll atoq \
 	sysconf isascii gettimeofday strsignal putc_unlocked fputc_unlocked \
-	fputs_unlocked getrusage iconv nl_langinfo
+	fputs_unlocked getrusage iconv nl_langinfo lstat
 do
 echo $ac_n "checking for $ac_func""... $ac_c" 1>&6
 echo "configure:3109: checking for $ac_func" >&5

gcc/configure.in

@@ -547,7 +547,7 @@ dnl gcc_AC_C_ENUM_BF_UNSIGNED
 AC_CHECK_FUNCS(strtoul bsearch popen \
 	strchr strrchr kill getrlimit setrlimit atoll atoq \
 	sysconf isascii gettimeofday strsignal putc_unlocked fputc_unlocked \
-	fputs_unlocked getrusage iconv nl_langinfo)
+	fputs_unlocked getrusage iconv nl_langinfo lstat)
 
 AC_CHECK_TYPE(ssize_t, int)
 

gcc/cppfiles.c

@@ -101,6 +101,7 @@ static int report_missing_guard		PARAMS ((splay_tree_node, void *));
 static splay_tree_node find_or_create_entry PARAMS ((cpp_reader *,
 						     const char *));
 static void handle_missing_header PARAMS ((cpp_reader *, const char *, int));
+static int remove_component_p	PARAMS ((const char *));
 
 /* Set up the splay tree we use to store information about all the
    file names seen in this compilation.  We also have entries for each
@@ -155,7 +156,8 @@ _cpp_never_reread (file)
 }
 
 /* Lookup a filename, which is simplified after making a copy, and
-   create an entry if none exists.  */
+   create an entry if none exists.  errno is nonzero iff a (reported)
+   stat() error occurred during simplification.  */
 static splay_tree_node
 find_or_create_entry (pfile, fname)
      cpp_reader *pfile;
@@ -208,6 +210,9 @@ open_file (pfile, filename)
   splay_tree_node nd = find_or_create_entry (pfile, filename);
   struct include_file *file = (struct include_file *) nd->value;
 
+  if (errno)
+    file->fd = -2;
+
   /* Don't retry opening if we failed previously.  */
   if (file->fd == -2)
     return 0;
@@ -643,7 +648,6 @@ handle_missing_header (pfile, fname, angle_brackets)
 	      p[len++] = '/';
 	    }
 	  memcpy (p + len, fname, fname_len + 1);
-	  _cpp_simplify_pathname (p);
 	  deps_add_dep (pfile->deps, p);
 	}
     }
@@ -1006,6 +1010,26 @@ remap_filename (pfile, name, loc)
   return name;
 }
 
+/* Returns true if it is safe to remove the final component of path,
+   when it is followed by a ".." component.  We use lstat to avoid
+   symlinks if we have it.  If not, we can still catch errors with
+   stat ().  */
+static int
+remove_component_p (path)
+     const char *path;
+{
+  struct stat s;
+  int result;
+
+#ifdef HAVE_LSTAT
+  result = lstat (path, &s);
+#else
+  result = stat (path, &s);
+#endif
+
+  return result == 0 && S_ISDIR (s.st_mode);
+}
+
 /* Simplify a path name in place, deleting redundant components.  This
    reduces OS overhead and guarantees that equivalent paths compare
    the same (modulo symlinks).
@@ -1018,16 +1042,23 @@ remap_filename (pfile, name, loc)
    //quux		//quux  (POSIX allows leading // as a namespace escape)
 
    Guarantees no trailing slashes.  All transforms reduce the length
-   of the string.  Returns PATH;
- */
+   of the string.  Returns PATH.  errno is 0 if no error occurred;
+   nonzero if an error occurred when using stat () or lstat ().  */
+
 char *
 _cpp_simplify_pathname (path)
     char *path;
 {
+#ifndef VMS
   char *from, *to;
-    char *base;
+  char *base, *orig_base;
   int absolute = 0;
 
+  errno = 0;
+  /* Don't overflow the empty path by putting a '.' in it below.  */
+  if (*path == '\0')
+    return path;
+
 #if defined (HAVE_DOS_BASED_FILE_SYSTEM)
   /* Convert all backslashes to slashes. */
   for (from = path; *from; from++)
@@ -1042,7 +1073,7 @@ _cpp_simplify_pathname (path)
   from = to = path;
 #endif
     
-    /* Remove redundant initial /s.  */
+  /* Remove redundant leading /s.  */
   if (*from == '/')
     {
       absolute = 1;
@@ -1058,83 +1089,74 @@ _cpp_simplify_pathname (path)
 	    to++;
 	}
     }
-    base = to;
 
+  base = orig_base = to;
   for (;;)
     {
+      int move_base = 0;
+
       while (*from == '/')
 	from++;
 
-	if (from[0] == '.' && from[1] == '/')
-	    from += 2;
-	else if (from[0] == '.' && from[1] == '\0')
-	    goto done;
-	else if (from[0] == '.' && from[1] == '.' && from[2] == '/')
-	{
-	    if (base == to)
-	    {
-		if (absolute)
-		    from += 3;
-		else
+      if (*from == '\0')
+	break;
+
+      if (*from == '.')
 	{
-		    *to++ = *from++;
-		    *to++ = *from++;
-		    *to++ = *from++;
-		    base = to;
-		}
-	    }
-	    else
+	  if (from[1] == '\0')
+	    break;
+	  if (from[1] == '/')
 	    {
-		to -= 2;
-		while (to > base && *to != '/') to--;
-		if (*to == '/')
-		    to++;
-		from += 3;
-	    }
+	      from += 2;
+	      continue;
 	    }
-	else if (from[0] == '.' && from[1] == '.' && from[2] == '\0')
+	  else if (from[1] == '.' && (from[2] == '/' || from[2] == '\0'))
 	    {
-	    if (base == to)
+	      /* Don't simplify if there was no previous component.  */
+	      if (absolute && orig_base == to)
 		{
-		if (!absolute)
-		{
-		    *to++ = *from++;
-		    *to++ = *from++;
-		}
+		  from += 2;
+		  continue;
 		}
-	    else
+	      /* Don't simplify if the previous component was "../",
+		 or if an error has already occurred with (l)stat.  */
+	      if (base != to && errno == 0)
 		{
-		to -= 2;
-		while (to > base && *to != '/') to--;
-		if (*to == '/')
-		    to++;
-	    }
-	    goto done;
-	}
-	else
-	    /* Copy this component and trailing /, if any.  */
-	    while ((*to++ = *from++) != '/')
-	    {
-		if (!to[-1])
+		  /* We don't back up if it's a symlink.  */
+		  *to = '\0';
+		  if (remove_component_p (path))
 		    {
+		      while (to > base && *to != '/')
 			to--;
-		    goto done;
+		      from += 2;
+		      continue;
 		    }
 		}
-	
+	      move_base = 1;
+	    }
 	}
 
- done:
-    /* Trim trailing slash */
-    if (to[0] == '/' && (!absolute || to > path+1))
-	to--;
+      /* Add the component separator.  */
+      if (to > orig_base)
+	*to++ = '/';
 
-    /* Change the empty string to "." so that stat() on the result
-       will always work. */
+      /* Copy this component until the trailing null or '/'.  */
+      while (*from != '\0' && *from != '/')
+	*to++ = *from++;
+
+      if (move_base)
+	base = to;
+    }
+    
+  /* Change the empty string to "." so that it is not treated as stdin.
+     Null terminate.  */
   if (to == path)
     *to++ = '.';
-    
   *to = '\0';
 
   return path;
+#else /* VMS  */
+  errno = 0;
+  return path;
+#endif /* !VMS  */
 }

gcc/cppinit.c

@@ -211,6 +211,8 @@ append_include_chain (pfile, dir, path, cxx_aware)
   struct stat st;
   unsigned int len;
 
+  if (*dir == '\0')
+    dir = xstrdup (".");
   _cpp_simplify_pathname (dir);
   if (stat (dir, &st))
     {

gcc/cpplib.c

@@ -729,12 +729,7 @@ do_line (pfile)
   cpp_get_token (pfile, &token);
   if (token.type == CPP_STRING)
     {
-      char *fname;
-      unsigned int len = token.val.str.len + 1;
-
-      fname = (char *) _cpp_pool_alloc (&pfile->ident_pool, len);
-      memcpy (fname, token.val.str.text, len);
-      _cpp_simplify_pathname (fname);
+      const char *fname = (const char *) token.val.str.text;
 
       /* Only accept flags for the # 55 form.  */
       if (! pfile->state.line_extension)