[syslinux] Syslinux search for config file

[Gert Hulselmans]

2012/8/30 Gert Hulselmans <hulselmansgert at gmail.com>:
> 2012/8/30 Tomas M <tomas at slax.org>:
>>>> I also tested 4.05, and it did NOT search the install directory if such
>>>>  directory is not in the "expected" list. Tomas also got the same result (as
>>>>  he wrote in a previous email in this same thread).
>>>
>>> He stated such but without more data, I can't be certain he's not
>>> encountering something that's already been resolved.
>>
>> I see symptoms as described by Ady Ady
>> I install syslinux from windows, using syslinux.exe (32bit binary),
>> which I got from syslinux 4.05 source distribution (there is the
>> binary precompiled).
>> # syslinux.exe -maf -d \slax\boot F:
>>
>
> I guess it is a bug in the windows version of the Syslinux installer:
>
>
>
> In win/syslinux.c, the directory path will replace all / characters with \
> (so -d /boot/blabla works the same as -d \boot\blabla):
> ================================================
>     /* Move the file to the desired location */
>     if (opt.directory) {
>         char new_ldlinux_name[strlen(opt.directory) + 16];
>         char *cp = new_ldlinux_name + 3;
>         const char *sd;
>         int slash = 1;
>
>         new_ldlinux_name[0] = opt.device[0];
>         new_ldlinux_name[1] = ':';
>         new_ldlinux_name[2] = '\\';
>
>         for (sd = opt.directory; *sd; sd++) {
>             char c = *sd;
>
>             if (c == '/' || c == '\\') {
>                 if (slash)
>                     continue;
>                 c = '\\';
>                 slash = 1;
>             } else {
>                 slash = 0;
>             }
>
>             *cp++ = c;
>         }
> ================================================
>
> In the syslinux_patch function of libinstaller/syslxmod.c:
> ================================================
>     /* Poke in the base directory path */
>     if (subdir) {
>         int sublen = strlen(subdir) + 1;
>         if (get_16_sl(&epa->dirlen) < sublen) {
>             fprintf(stderr, "Subdirectory path too long... aborting
> install!\n");
>             exit(1);
>         }
>         memcpy_to_sl(ptr(boot_image, &epa->diroffset), subdir, sublen);
>     }
> ================================================
>
> The subdir name that is written to the extended patch area dir offset
> (epa->diroffset)
> contains always backslashes, when you run the Windows syslinux installer.
> Probably Syslinux can't handle backslashes, when booted (in the configuration
> files you also need to use forward slashes).
>
>
> Run bootinfoscript: http://sourceforge.net/projects/bootinfoscript/
>
> When you install Syslinux from linux, you will see something like this:
>
> sdb1: __________________________________________________________________________
>
>     File system:       vfat
>     Boot sector type:  SYSLINUX 4.05 2011-12-09
>     Boot sector info:  Syslinux looks at sector 952269 of /dev/sdb1 for its
>                        second stage. SYSLINUX is installed in the
>                        /boot/syslinux2 directory. No errors found in the Boot
>                        Parameter Block.
>
>
>
> When you install Syslinux from Windows, I expect that you will see
> something like this:
>
> sdb1: __________________________________________________________________________
>
>     File system:       vfat
>     Boot sector type:  SYSLINUX 4.05 2011-12-09
>     Boot sector info:  Syslinux looks at sector 952269 of /dev/sdb1 for its
>                        second stage. SYSLINUX is installed in the
>                        \boot\syslinux2 directory. No errors found in the Boot
>                        Parameter Block.
>
>
>> Probably you have some syslinux.cfg file or similar somewhere in the
>> common paths. Please try with blank sdb media and only one directory
>> "b" in the root
>
> I installed Syslinux to a different directory in the past (from linux)
> and it worked fine. I tried directories with dots and spaces.
>
>
> - Gert Hulselmans

After a closer look at the source code, the following should work:

  syslinux.exe -maf -d /slax/boot F:

The forward slashes are replaced with backward slashes after calling
syslinux_patch.

- Gert Hulselmans