[Crash-utility] [PATCH] Fix junk values when run crash on a .gz file

[Dave Anderson]

----- Original Message -----
> On Tue, 2011-12-06 at 09:50 -0500, Dave Anderson wrote:
> > 
> > ----- Original Message -----
> > > On Mon, 2011-12-05 at 15:03 -0500, Dave Anderson wrote:
> > > > 
> > > > ----- Original Message -----
> > > > >
> > > > > So I guess the proper thing to do would be to check for the FNAME bit
> > > > > in the FLG byte, and if it's not set, I guess we could either accept
> > > > > the file without prejudice, or print a message indicating that the
> > > > > name has been stripped and that -f should be used.
> > > > 
> > > > I wasn't aware of "gzip -n" or "gzip --no-name" when I wrote the
> > > > original function.  How does the attached patch work for you?
> > > > Instead of either suggestion above, it will just print a NOTE if
> > > > you don't use "-f".
> > > > 
> > > > Dave
> > > > 
> > > Hi Dave,
> > > 
> > > The attached patch works for me. It prints the file name is
> > > unknown. How about printing the file name is unknown and -f should be used as
> > > you  mentioned in the previous mail.
> > 
> > OK, will do -- queued for crash-6.0.2.
> > 
> > Thanks
> >   Dave
> > 
> 
> Hi Dave,
> 
> A return statement is missing in the if condition when a .gz file header
> contains no filename. Request you to include the same.
> 
> --- crash-6.0.1/symbols.c.orig
> +++ crash-6.0.1/symbols.c
> @@ -2983,6 +2983,8 @@ is_compressed_kernel(char *file, char **
>  #define GZIP  (1)
>  #define BZIP2 (2)
>  
> +#define FNAME (1 << 3)
> +
>         if ((fd = open(file, O_RDONLY)) < 0)
>                 return FALSE;
>  
> @@ -2995,7 +2997,12 @@ is_compressed_kernel(char *file, char **type = 0;
>  
>         if ((header[0] == 0x1f) && (header[1] == 0x8b) && (header[2] == 8)) {
> -               if (!STRNEQ((char *)&header[10], "vmlinux") &&
> +               if (!(header[3] & FNAME)) {
> +                       if (!(st->flags & FORCE_DEBUGINFO))
> +                               error(NOTE, "%s: "
> +                                   "original filename unknown\n\n",
> +                                       file);
> 				return FALSE;----> to be included.
> +               } else if (!STRNEQ((char *)&header[10], "vmlinux") &&
>                     !(st->flags & FORCE_DEBUGINFO)) {
>                         error(INFO, "%s: compressed file name does
>                         not "
>                             "start with \"vmlinux\"\n", &header[10]);

Actually I did it that way on purpose, so that the "gzip -n" vmlinux file
would be accepted on face value -- but with the warning.  The user is not
doing anything wrong that should force them to have to re-enter the command.

This is what I have queued: 

        if ((header[0] == 0x1f) && (header[1] == 0x8b) && (header[2] == 8)) {
                if (!(header[3] & FNAME)) {
                        if (!(st->flags & FORCE_DEBUGINFO)) {
                                error(INFO, "%s: "
                                    "original filename unknown\n",
                                        file);
                                error(CONT,
                                    "Use \"-f %s\" on command line to prevent this message.\n\n",
                                        file);
                        }
                } else if (!STRNEQ((char *)&header[10], "vmlinux") &&
                    !(st->flags & FORCE_DEBUGINFO)) {
                        error(INFO, "%s: compressed file name does not "
                            "start with \"vmlinux\"\n", &header[10]);
                        error(CONT,
                            "Use \"-f %s\" on command line to override.\n\n",
                                file);
                        return FALSE;
                }
                type = GZIP;
        }

Dave