Date: Sun, 11 Oct 1998 02:06:17 -0700 (PDT) From: Matthew Dillon <dillon@backplane.com> To: Peter Wemm <peter@netplex.com.au> Cc: Bruce Evans <bde@FreeBSD.ORG>, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/lib/libc/gen popen.c Message-ID: <199810110906.CAA02043@apollo.backplane.com> References: <199810110309.LAA18511@spinner.netplex.com.au>
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:Bruce Evans wrote:
:> bde 1998/10/10 12:30:45 PDT
:>
:> Modified files:
:> lib/libc/gen popen.c
:> Log:
:> vfork -> fork. The child calls execl() which calls malloc(), so
:> vfork() can't be used. We could use alloca() in execl() so that
:> it can be called between vfork() and execve(), but a "portable"
:...
:
:Why not fix it properly by not using execl()?
Wait a second!!!!!! vfork() was specifically designed for situations
where you call the exec*() functions. That's the whole point of
using vfork() rather then fork()!!!!!
If execl() is not compatible with vfork(), then execl() is seriously
broken. And I do mean seriously. I can't begin to count the number
of times I use vfork()/execl() in programs.
The problem ought to be easily solvable by having the exec*() functions
cache the returned argv in a static and 'free' them on the following
call before allocating a new copy, so the parent process does not
leak memory. Frankly, I'd prefer a solution that doesn't touch malloc
at all... if it were me I'd just take &arg and be done with it, but
alloca() is probably better then that. Still not fun, but better.
-Matt
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