On Tue, Jun 5, 2018 at 7:43 PM, Michal Suchanek [off-list ref] wrote:

Hello,

due to work on the fadump_extra_args I looked at the kernel parameter parser
and found its grammar rather curious.

It supports double quotes but not any other quoting characters so double quotes
cannot be quoted. What's more, the quotes can be anywhere in the parameter
name or value and are interpteted but are removed only from start and end of
the parameter value.

These are the patches not specific to fadump which somewhat straighten the
qouting grammar to make it on par with common shell interpreters.

I didn't notice any use of string_unescape_*() functionality. So, your
patch is kinda very specific to some narrow subset of escaping and
unescaping stuff.
Thus, it's still not on par with shell, right?

Specifically double and single quotes can be used for quoting as well as
backslashes with the usual shell semantic. All quoting characters are removed
while the parameters are parsed.

Previous versions (including the fadump part) can be found here:

https://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg126148.html
https://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg123639.html

Thanks

Michal

Michal Suchanek (5):
  lib/cmdline.c: Add backslash support to kernel commandline parsing.
  Documentation/admin-guide: backslash support in kernel arguments.
  init/main.c: simplify repair_env_string.
  lib/cmdline.c: Implement single quotes in commandline argument
    parsing.
  Documentation/admin-guide: single quotes in kernel arguments.

 Documentation/admin-guide/kernel-parameters.rst |  5 +-
 init/main.c                                     | 13 ++---
 lib/cmdline.c                                   | 63 +++++++++++++++----------
 3 files changed, 46 insertions(+), 35 deletions(-)

--
2.13.6

-- 
With Best Regards,
Andy Shevchenko
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