Re: [Valgrind-developers] Executing scripts missing a "#!" line

[Nicholas N. <nj...@cs...>]

On Wed, 27 Jul 2005, Julian Seward wrote:

>>   - if it's an executable, execute natively
>>   - if it's a script with a "#!" line, use the named interpreter
>>   - else default to interpreting with /bin/sh
>>
>> Valgrind doesn't do that 3rd step.  Perhaps it should?
>
> I guess it should, yes.  How intrusive a change would it be?

Not very, it's just a few lines in m_ume.c.  Below is a preliminary patch 
(done with "diff -b", because I had to indent a section of code).  I 
haven't tested it thoroughly but the cases I tested worked.  I don't know 
whether defaulting to /bin/sh is Linux-specific, though.

N



*** ../trunk7/coregrind/m_ume.c Mon Jul 18 19:33:34 2005
--- coregrind/m_ume.c   Wed Jul 27 16:32:11 2005
***************
*** 581,587 ****


   static int match_script(const char *hdr, Int len)
   {
!    return (len > 2) && memcmp(hdr, "#!", 2) == 0;
   }

--- 581,590 ----


+ // If we don't match as ELF, assume it's a script.  (If there's not #! 
line,
+ // we default to assuming a /bin/sh script.)
   static int match_script(const char *hdr, Int len)
   {
!    //return (len > 2) && memcmp(hdr, "#!", 2) == 0;
!    return True;
   }

***************
*** 595,598 ****
--- 598,603 ----
      int eol;

+    if (hdr[0] == '#' && hdr[1] == '!') {
+
         interp = hdr + 2;
         while(interp < end && (*interp == ' ' || *interp == '\t'))
***************
*** 635,638 ****
--- 640,649 ----
            printf("#! script: interp_name=\"%s\" interp_args=\"%s\"\n",
                   info->interp_name, info->interp_args);
+
+    } else {
+       interp = "/bin/sh";
+       info->interp_name = interp;
+       info->interp_args = NULL;
+    }

      return do_exec_inner(interp, info);