Re: [PATCH 1/2] Windows libibery: Don't quote args unnecessarily

Re: [PATCH 1/2] Windows libibery: Don't quote args unnecessarily

[Kai Tietz]

Hello Ray,

Patches to libiberty need to be cross-posted to binutils, gdb, and gcc ML.  I did so for you now.

----- Original Message -----
> We only quote arguments that contain spaces, \n \t \v
> or " characters to prevent wasting 2 characters per
> argument of the CreateProcess() 32,768 limit.
> 
> libiberty/
> 	* pex-win32.c (argv_to_cmdline): Don't quote
> 	args unnecessarily

The changes to changelog shouldn't be part of the patch itself.  Just write into mail the changelog entry patch needs to have.  Eg as:

Changelog libiberty/
 	* pex-win32.c (argv_to_cmdline): Don't quote
 	args unnecessarily

> ---
>  libiberty/ChangeLog   |  5 +++++
>  libiberty/pex-win32.c | 48 +++++++++++++++++++++++++++++++++++++++---------
>  2 files changed, 44 insertions(+), 9 deletions(-)
> 
> diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
> index d9a208b..f6a4f8f 100644
> --- a/libiberty/ChangeLog
> +++ b/libiberty/ChangeLog
> @@ -1,3 +1,8 @@
> +2014-04-14 Ray Donnelly <mingw.android@gmail.com>
> +
> +	* pex-win32.c (argv_to_cmdline): Don't quote
> +	args unnecessarily.
> +
>  2014-04-17  Jakub Jelinek  <jakub@redhat.com>
>  
>  	PR sanitizer/56781
> diff --git a/libiberty/pex-win32.c b/libiberty/pex-win32.c
> index eae72c5..775b53c 100644
> --- a/libiberty/pex-win32.c
> +++ b/libiberty/pex-win32.c
> @@ -340,17 +340,26 @@ argv_to_cmdline (char *const *argv)
>    char *p;
>    size_t cmdline_len;
>    int i, j, k;
> +  int needs_quotes;
>  
>    cmdline_len = 0;
>    for (i = 0; argv[i]; i++)
>      {
> -      /* We quote every last argument.  This simplifies the problem;
> -	 we need only escape embedded double-quotes and immediately
> +      /* We only quote arguments that contain spaces, \n \t \v or "
> characters
> +	 to prevent wasting 2 chars per argument of the CreateProcess 32k char
> +	 limit We need only escape embedded double-quotes and immediately
>  	 preceeding backslash characters.  A sequence of backslach characters
>  	 that is not follwed by a double quote character will not be
>  	 escaped.  */
> +      needs_quotes = 0;
>        for (j = 0; argv[i][j]; j++)
>  	{
> +	  if (argv[i][j] == ' '  || argv[i][j] == '\n' ||
> +	      argv[i][j] == '\t' || argv[i][j] == '"' )
> +	    {
Here seems to be an intend issue.
> +	      needs_quotes = 1;
> +	    }
> +
>  	  if (argv[i][j] == '"')
>  	    {
>  	      /* Escape preceeding backslashes.  */
> @@ -362,16 +371,34 @@ argv_to_cmdline (char *const *argv)
>  	}
>        /* Trailing backslashes also need to be escaped because they will be
>           followed by the terminating quote.  */
> -      for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
> -	cmdline_len++;
> +      if (needs_quotes)
> +        {
> +          for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
> +            cmdline_len++;
> +        }
>        cmdline_len += j;
> -      cmdline_len += 3;  /* for leading and trailing quotes and space */
> +      /* for leading and trailing quotes and space */
> +      cmdline_len += needs_quotes * 2 + 1;
>      }
>    cmdline = XNEWVEC (char, cmdline_len);
>    p = cmdline;
>    for (i = 0; argv[i]; i++)
>      {
> -      *p++ = '"';
> +      needs_quotes = 0;
> +      for (j = 0; argv[i][j]; j++)
> +        {
> +          if (argv[i][j] == ' '  || argv[i][j] == '\n' ||
> +              argv[i][j] == '\t' || argv[i][j] == '"' )
> +            {
> +              needs_quotes = 1;
> +              break;
> +            }
> +        }
> +
> +      if (needs_quotes)
> +        {
> +          *p++ = '"';
> +        }
>        for (j = 0; argv[i][j]; j++)
>  	{
>  	  if (argv[i][j] == '"')
> @@ -382,9 +409,12 @@ argv_to_cmdline (char *const *argv)
>  	    }
>  	  *p++ = argv[i][j];
>  	}
> -      for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
> -	*p++ = '\\';
> -      *p++ = '"';
> +      if (needs_quotes)
> +        {
> +          for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
> +            *p++ = '\\';
> +          *p++ = '"';
> +        }
>        *p++ = ' ';
>      }
>    p[-1] = '\0';
> --
> 1.9.2

Patch itself makes sense.  Let see if there are additional comments.

Regards,
Kai

Re: [PATCH 1/2] Windows libibery: Don't quote args unnecessarily

[Eli Zaretskii]

> Date: Sat, 19 Apr 2014 16:23:33 -0400 (EDT)
> From: Kai Tietz <ktietz@redhat.com>
> Cc: gcc-patches@gcc.gnu.org, ktietz70@gmail.com,        "binutils@sourceware.org Development" <binutils@sourceware.org>,        gdb-patches@sourceware.org
> 
> > +      /* We only quote arguments that contain spaces, \n \t \v or " characters
> > +	 to prevent wasting 2 chars per argument of the CreateProcess 32k char
> > +	 limit We need only escape embedded double-quotes and immediately
> >  	 preceeding backslash characters.  A sequence of backslach characters
> >  	 that is not follwed by a double quote character will not be
> >  	 escaped.  */
> > +      needs_quotes = 0;
> >        for (j = 0; argv[i][j]; j++)
> >  	{
> > +	  if (argv[i][j] == ' '  || argv[i][j] == '\n' ||
> > +	      argv[i][j] == '\t' || argv[i][j] == '"' )
> > +	    {
> Here seems to be an intend issue.
> > +	      needs_quotes = 1;
> > +	    }

I think you can omit the \n case, since command arguments on Windows
cannot possibly include newlines.  Also, the comment speaks about \v,
but I see no code to handle that (and am not sure you should bother in
that case as well).

> Patch itself makes sense.

Yes, I agree.

Re: [PATCH 1/2] Windows libibery: Don't quote args unnecessarily

[Joel Brobecker]

> Changelog libiberty/
>  	* pex-win32.c (argv_to_cmdline): Don't quote
>  	args unnecessarily

Some minor comments...

> > diff --git a/libiberty/pex-win32.c b/libiberty/pex-win32.c
> > index eae72c5..775b53c 100644
> > --- a/libiberty/pex-win32.c
> > +++ b/libiberty/pex-win32.c
> > @@ -340,17 +340,26 @@ argv_to_cmdline (char *const *argv)
> >    char *p;
> >    size_t cmdline_len;
> >    int i, j, k;
> > +  int needs_quotes;
> >  
> >    cmdline_len = 0;
> >    for (i = 0; argv[i]; i++)
> >      {
> > -      /* We quote every last argument.  This simplifies the problem;
> > -	 we need only escape embedded double-quotes and immediately
> > +      /* We only quote arguments that contain spaces, \n \t \v or "
> > characters
> > +	 to prevent wasting 2 chars per argument of the CreateProcess 32k char
> > +	 limit We need only escape embedded double-quotes and immediately

Period missing after "limit".  JIC, remember that we ask that periods be
followed by 2 spaces.

> >  	 preceeding backslash characters.  A sequence of backslach characters
> >  	 that is not follwed by a double quote character will not be
> >  	 escaped.  */
> > +      needs_quotes = 0;
> >        for (j = 0; argv[i][j]; j++)
> >  	{
> > +	  if (argv[i][j] == ' '  || argv[i][j] == '\n' ||
> > +	      argv[i][j] == '\t' || argv[i][j] == '"' )

GNU Coding Style requirement: Binary operators should be at the start
of the next line, not at the end. For instance:

	  if (argv[i][j] == ' '  || argv[i][j] == '\n'
              || argv[i][j] == '\t' || argv[i][j] == '"')

Also, watch out for the extra space before ')' - please remove it.


> > +	    {
> Here seems to be an intend issue.
> > +	      needs_quotes = 1;
> > +	    }
> > +
> >  	  if (argv[i][j] == '"')
> >  	    {
> >  	      /* Escape preceeding backslashes.  */
> > @@ -362,16 +371,34 @@ argv_to_cmdline (char *const *argv)
> >  	}
> >        /* Trailing backslashes also need to be escaped because they will be
> >           followed by the terminating quote.  */
> > -      for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
> > -	cmdline_len++;
> > +      if (needs_quotes)
> > +        {
> > +          for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
> > +            cmdline_len++;
> > +        }
> >        cmdline_len += j;
> > -      cmdline_len += 3;  /* for leading and trailing quotes and space */
> > +      /* for leading and trailing quotes and space */
> > +      cmdline_len += needs_quotes * 2 + 1;
> >      }
> >    cmdline = XNEWVEC (char, cmdline_len);
> >    p = cmdline;
> >    for (i = 0; argv[i]; i++)
> >      {
> > -      *p++ = '"';
> > +      needs_quotes = 0;
> > +      for (j = 0; argv[i][j]; j++)
> > +        {
> > +          if (argv[i][j] == ' '  || argv[i][j] == '\n' ||
> > +              argv[i][j] == '\t' || argv[i][j] == '"' )

Same as above.

> > +            {
> > +              needs_quotes = 1;
> > +              break;
> > +            }
> > +        }
> > +
> > +      if (needs_quotes)
> > +        {
> > +          *p++ = '"';
> > +        }
> >        for (j = 0; argv[i][j]; j++)
> >  	{
> >  	  if (argv[i][j] == '"')
> > @@ -382,9 +409,12 @@ argv_to_cmdline (char *const *argv)
> >  	    }
> >  	  *p++ = argv[i][j];
> >  	}
> > -      for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
> > -	*p++ = '\\';
> > -      *p++ = '"';
> > +      if (needs_quotes)
> > +        {
> > +          for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
> > +            *p++ = '\\';
> > +          *p++ = '"';
> > +        }
> >        *p++ = ' ';
> >      }
> >    p[-1] = '\0';
> > --
> > 1.9.2
> 
> Patch itself makes sense.  Let see if there are additional comments.
> 
> Regards,
> Kai

-- 
Joel