Date: Fri, 24 Mar 2017 00:38:24 -0700 From: Cy Schubert <Cy.Schubert@komquats.com> To: Ian Lepore <ian@freebsd.org>, Roman Divacky <rdivacky@freebsd.org>, Warner Losh <imp@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r315773 - head/sbin/devd Message-ID: <201703240738.v2O7cOhb003757@slippy.cwsent.com> In-Reply-To: Message from Cy Schubert <Cy.Schubert@komquats.com> of "Thu, 23 Mar 2017 20:40:14 -0700." <201703240340.v2O3eEKh002609@slippy.cwsent.com>
next in thread | previous in thread | raw e-mail | index | archive | help
In message <201703240340.v2O3eEKh002609@slippy.cwsent.com>, Cy Schubert writes: > In message <1490297671.58015.102.camel@freebsd.org>, Ian Lepore writes: > > On Thu, 2017-03-23 at 19:58 +0100, Roman Divacky wrote: > > > On Thu, Mar 23, 2017 at 02:36:51AM +0000, Warner Losh wrote: > > > > > > > > Author: imp > > > > Date: Thu Mar 23 02:36:51 2017 > > > > New Revision: 315773 > > > > URL: https://svnweb.freebsd.org/changeset/base/315773 > > > > > > > > Log: > > > > Implement quote escaping. String values may now contain " if you > > > > it is preceded by \. > > > > > > > > foo="I \"like\" C++" > > > > > > > > gives the value 'I "like" C++' to the variable 'foo'. If a > > > > character > > > > other than " follows the \, both the \ and that character are > > > > passed > > > > through. > > > > > > > > Differential Revision: https://reviews.freebsd.org/D6286 > > > > Sponsored by: Netflix > > > > > > > > Modified: > > > > head/sbin/devd/devd.cc > > > > head/sbin/devd/devd.hh > > > > > > > > Modified: head/sbin/devd/devd.cc > > > > =================================================================== > > > > =========== > > > > --- head/sbin/devd/devd.cc Thu Mar 23 02:33:27 2017 ( > > > > r315772) > > > > +++ head/sbin/devd/devd.cc Thu Mar 23 02:36:51 2017 ( > > > > r315773) > > > > @@ -411,6 +411,32 @@ var_list::is_set(const string &var) cons > > > > return (_vars.find(var) != _vars.end()); > > > > } > > > > > > > > +/** fix_value > > > > + * > > > > + * Removes quoted characters that have made it this far. \" are > > > > + * converted to ". For all other characters, both \ and following > > > > + * character. So the string 'fre\:\"' is translated to 'fred\:"'. > > > > + */ > > > > +const std::string & > > > > +var_list::fix_value(const std::string &val) const > > > > +{ > > > > + char *tmp, *dst; > > > > + const char *src; > > > > + std::string *rv; > > > > + > > > > + dst = tmp = new char[val.length()]; > > > > + src = val.c_str(); > > > > + while (*src) { > > > > + if (*src == '\\' && src[1] == '"') > > > > + src++; > > > > + else > > > > + *dst++ = *src++; > > > > + } > > > > + rv = new string(tmp); > > > > + delete tmp; > > > > + return *rv; > > > > +} > > > Can the temporary char[] be stack allocated? Also, when returning a > > > reference to > > > a heap allocated string who is responsible for freeing it? Perhaps > > > you can just > > > return std::string and let the compiler optimize it? > > > > > > Roman > > > > > > > Returning a reference to a new'd string is not good. > > > > IMO, the implementation of the function should take into account the > > idea that embedded escaped quotes are rare. The function should be > > optimized for readability and the common case of simply copying the > > string unmodified, something like: > > > > > > std::string > > var_list::fix_value(const std::string &val) const > > { > > std::string rv(val); > > std::string::size_type pos(0); > > > > while ((pos = rv.find("\\\"", pos)) != rv.npos) { > > rv.erase(pos, 1); > > } > > return (rv); > > } > > This revision caused devd a little gas. It failed to start moused for usb > attached mice (ums0 & ums1) to my latpop and nut failed to recognize my USB > connected UPS on a server. downstairs due to a permission issue which nut > provides a devd.conf file with: > > chgrp uucp /dev/$cdev; chmod g+rw /dev/$cdev Hi Ian, Your example above fixes the problem. -- Cheers, Cy Schubert <Cy.Schubert@cschubert.com> FreeBSD UNIX: <cy@FreeBSD.org> Web: http://www.FreeBSD.org The need of the many outweighs the greed of the few.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201703240738.v2O7cOhb003757>