Fix PR50293 - LTO plugin with space in path

Joseph, Thanks for your valuable comments. See my reply and new patch below.

> -----Original Message-----
> From: Joseph Myers [mailto:joseph@codesourcery.com]
> Sent: Monday, February 18, 2013 06:16
> To: Joey Ye
> Cc: gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH] Fix PR50293 - LTO plugin with space in path
> 
> On Sun, 17 Feb 2013, Joey Ye wrote:
> 
> > +static char * convert_white_space(char * orig);
> 
> Please fix formatting in many places in this patch to follow the GNU
> Coding Standards.  No space after '*', but space before '('; there seem
> to
> be various other formatting problems as well.
My bad. All fixed.

> 
> > +/* Insert back slash before spaces in a string, to avoid path
> > +   that has space in it broken into multiple arguments.  */
> 
> That doesn't seem to be a proper specification of the interface to this
> function.  What are the semantics of ORIG?  A string that is a filename,
> or something else?  What are the exact semantics of the return value for
> quoting - is it correct for the function to convert a (backslash, space)
> pair to (backslash, backslash, space) or not?  Is anything special in
> the
> return value other than backslash and space, and how are any special
> characters in the return value to be interpreted?
> 
> As it seems like this function frees the argument (why?) this also needs
> to be specified in the comment as part of the semantics of the function.
This function might need a string longer than original one to accommodate
additional back slashes. So it has to xmalloc a new string. The original
string should be freed in such a case. However, it is tedious to caller
to figure out that conversion does happens and free the orig. The solution
is for this function to free it when conversion happens.

By doing so it is required that orig must be allocated and can be freed,
as the newly added comments described explicitly.
> 
> It would be a good idea for you to give a more detailed explanation in
> the
> next version of the patch submission of how the path, before the patch,
> got processed so that the spaces were wrongly interpreted.  That might
> help make clearer whether the interface to this new function is actually
> correct, since the subsequent operations on the return value should act
> as
> an inverse to the operation carried out by this function.
> 
> --
> Joseph S. Myers
> joseph@codesourcery.com

 /* The Specs Language
 
@@ -6595,6 +6596,7 @@
 				    X_OK, false);
   if (lto_wrapper_file)
     {
+      lto_wrapper_file = convert_white_space (lto_wrapper_file);
       lto_wrapper_spec = lto_wrapper_file;
       obstack_init (&collect_obstack);
       obstack_grow (&collect_obstack, "COLLECT_LTO_WRAPPER=",
@@ -7005,12 +7007,13 @@
 			      + strlen (fuse_linker_plugin), 0))
 #endif
 	    {
-	      linker_plugin_file_spec = find_a_file (&exec_prefixes,
+	      char * temp_spec = find_a_file (&exec_prefixes,
 						     LTOPLUGINSONAME, R_OK,
 						     false);
-	      if (!linker_plugin_file_spec)
+	      if (!temp_spec)
 		fatal_error ("-fuse-linker-plugin, but %s not found",
 			     LTOPLUGINSONAME);
+	      linker_plugin_file_spec = convert_white_space (temp_spec);
 	    }
 #endif
 	  lto_gcc_spec = argv[0];
@@ -8506,3 +8509,52 @@
   free (name);
   return result;
 }
+
+/* Insert back slash before spaces in orig (usually a file path), to 
+   avoid being broken by spec parser.
+
+   This function is needed as do_spec_1 treats white space (' ' and '\t')
+   as the end of an argument. But in case of -plugin /usr/gcc
install/xxx.so,
+   the filename should be treated as a single argument rather than being
+   broken into multiple. Solution is to insert '\\' before the space in a 
+   filename.
+   
+   This function converts and only converts all occurrance of ' ' 
+   to '\\' + ' ' and '\t' to '\\' + '\t'.  For example:
+   "a b"  -> "a\\ b"
+   "a  b" -> "a\\ \\ b"
+   "a\tb" -> "a\\\tb"
+   "a\\ b" -> "a\\\\ b"
+
+   orig: input null-terminating string that was allocated by xalloc. The
+   memory it points to might be freed in this function. Behavior undefined
+   if orig isn't xalloced or is freed already at entry.
+
+   Return: orig if no conversion needed. orig if conversion needed but no
+   sufficient memory for a new string. Otherwise a newly allocated string
+   that was converted from orig.  */
+
+static char * convert_white_space (char *orig)
+{
+  int len, number_of_space = 0;
+  if (orig == NULL) return orig;
+
+  for (len=0; orig[len]; len++)
+    if (orig[len] == ' ' || orig[len] == '\t') number_of_space ++;
+
+  if (number_of_space)
+    {
+      char * new_spec = (char *)xmalloc (len + number_of_space + 1);
+      int j,k;
+      if (new_spec == NULL) return orig;
+
+      for (j=0, k=0; j<=len; j++, k++)
+	{
+	  if (orig[j] == ' ' || orig[j] == '\t') new_spec[k++] = '\\';
+	  new_spec[k] = orig[j];
+	}
+      free (orig);
+      return new_spec;
+  }
+  else return orig;
+}

On Mon, 18 Feb 2013, Joey Ye wrote:

> +static char * convert_white_space (char *);

No space after "*".

> -	      linker_plugin_file_spec = find_a_file (&exec_prefixes,
> +	      char * temp_spec = find_a_file (&exec_prefixes,
>  						     LTOPLUGINSONAME, R_OK,
>  						     false);

The indentation of the following lines looks odd after this patch; unless 
that's just an effect of TABs plus quoting, make sure they are reindented 
to line up with the new position of the opening '('.

> +/* Insert back slash before spaces in orig (usually a file path), to 

Capitalize variable names when referring to the value of the variable, so 
ORIG; likewise elsewhere in this comment.  Single work "backslash".

> +   the filename should be treated as a single argument rather than being

"file name" should be two words, according to the GNU Coding Standards.

> +   This function converts and only converts all occurrance of ' ' 

"occurrence"

> +   Return: orig if no conversion needed. orig if conversion needed but no
> +   sufficient memory for a new string. Otherwise a newly allocated string

Returning wrong results on insufficient memory doesn't make sense.  
Anyway, xmalloc always exits the program if there is insufficient memory, 
so you don't need any code to allow for that case.

> +static char * convert_white_space (char *orig)

Newline, not space, between return type and function name, so that the 
function name comes at the start of the line.

> +  if (orig == NULL) return orig;

The comment didn't mention NULL as a valid argument, and it doesn't appear 
NULL can actually be passed to this function.  So don't include code to 
handle that case.

> +  for (len=0; orig[len]; len++)

Spaces around "=".

> +    if (orig[len] == ' ' || orig[len] == '\t') number_of_space ++;

No space before "++", but put the body of the "if" on a separate line.

> +      char * new_spec = (char *)xmalloc (len + number_of_space + 1);

No space after "*".  Space in the cast after "(char *)".

> +      int j,k;

Space after ",".

> +      if (new_spec == NULL) return orig;

As discussed above, not needed.

> +      for (j=0, k=0; j<=len; j++, k++)

Spaces around "=" and "<=".

> +	  if (orig[j] == ' ' || orig[j] == '\t') new_spec[k++] = '\\';

Put the "if" both on a separate line.

> +  else return orig;

Put the "else" body on a separate line.