Apple's libc shells out to Perl to implement wordexp

Post by JoachimS » Tue, Feb 10, 2015, 9:25 AM UTC

dxq wrote: post #18

mrpippy wrote: post #17

Earlier quoted context omitted.

The current one is a derivative of NetBSD's implementation (where it shells out to use a sh builtin)

Judging by both the source code and its placement in the repository (gen/FreeBSD/wordexp.c), I'm thinking it's a derivative of the FreeBSD implementation (which may itself be a derivative of the NetBSD implementation, or perhaps the other way around).

Post by Intermernet » Tue, Feb 10, 2015, 9:28 AM UTC

adamnemecek wrote: post #15

Intermernet wrote: post #2

Sorry, I don't have a Mac to check, but does the OSX build of Perl depend on libc? Also, that code seems to be from 2008 (or at least that's the latest year in the copyright header) despite the commit being from 2012. Does anyone know if this has been updated? Inserting a NUL byte between each word, and at the end doesn't sound like it requires Perl...

> otool -L /usr/bin/perl /usr/bin/perl: /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1151.14.0) /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1213.0.0)

Post by nandemo » Tue, Feb 10, 2015, 9:33 AM UTC

vertex-four wrote: post #31

nandemo wrote: post #13

Earlier quoted context omitted.

Performance is the least of my worries here. I'd be more worried about security, and plain dependency management. I mean, let's say this libc thing is supposed to be installed in quite a lot of systems, are we really sure that perl thing is installed in all of those systems? And what if, by some crazy coincidence, perl happens to depend on libc?

> I mean, let's say this libc thing is supposed to be installed in quite a lot of systems Apple's libc is not an independent thing to them - it's a part of OSX and iOS. You're not supposed to be able to take it out and use it for other things.

Post by tedunangst » Tue, Feb 10, 2015, 10:51 AM UTC

JoachimS wrote: post #35

cnvogel wrote: post #5

As it's already written in the manual... http://linux.die.net/man/3/wordexp wordexp, wordfree - perform word expansion like a posix-shell So, the implementer decided to take the short route, and just spawn a shell which, essentially, gets passed the input data to wordexp(), to do the work. But, of course, having something that starts with such a comment... /* XXX this is _not_ designed to be fast (...) wordexp is als…

Is wordexp() a requiement for being POSIX compatible? I searched through the FreeBSD repo on Gitbub and the only references to wordexp is basically the code itself. Searching the whole Github does not show many things either. How common is the function in practice and how important is it?

Post by jes » Tue, Feb 10, 2015, 11:14 AM UTC

smcl wrote: post #37

jes wrote: post #21

Earlier quoted context omitted.

With respect, is there evidence to support your claim? My direct experience is that I have received value far in excess of what I have had to pay for the Apple products and services I have purchased over the years. For example, I'm typing this reply on my PowerBook, which I use all day, every day in my work. I also have my iPhone with me constantly, and use it heavily. Finally, the Apple brand was said to be worth ab…

OT, but you're still using a Powerbook? That's pretty impressive. Which generation\year was it? I'm guessing you've had to swap out batteries and upgrade hard drive - have you had to modify anything else?