Date: Mon, 14 Oct 1996 01:50:03 -0700 (PDT) From: Bruce Evans <bde@zeta.org.au> To: freebsd-bugs Subject: Re: misc/1791: syslimits.h does not allow overriding default value of ARG_MAX Message-ID: <199610140850.BAA13957@freefall.freebsd.org>
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The following reply was made to PR misc/1791; it has been noted by GNATS.
From: Bruce Evans <bde@zeta.org.au>
To: FreeBSD-gnats-submit@FreeBSD.org, tegge@itea.ntnu.no
Cc: Subject: Re: misc/1791: syslimits.h does not allow overriding default value of ARG_MAX
Date: Mon, 14 Oct 1996 18:37:04 +1000
> It is not possible to specify an alternative value of ARG_MAX
> in the kernel config file, since /usr/src/sys/sys/syslimits.h
> defines ARG_MAX even if it was defined.
This isn't a bug. Defining ARG_MAX in <limits.h> advertises to
applications that ARG_MAX is a constant with the given value. The
only correct way to change it is to change the header and recompile
all applications that depend on it (ps, xargs and who-knows-what
else).
The best way to fix the problem is to remove the definition of
ARG_MAX from <limits.h> and then fix everything that (bogusly)
depends on it. Non-bogus dependencies on it look like this:
#ifdef ARG_MAX
char buf[ARG_MAX];
#else
long arg_max;
char *buf;
arg_max = sysconf(_SC_ARG_MAX);
if (arg_max == -1)
barf("sysconf");
st_arg_max = (size_t)arg_max;
if (st_arg_max != arg_max);
barf("unrepresentable arg_max");
buf = malloc(st_arg_max);
if (buf == NULL)
barf("malloc");
#endif
The kernel should use some other name for ARG_MAX to avoid confusion.
I have fixed most the corresponding problems for OPEN_MAX and CHILD_MAX.
They are now named PROC0_RLIMIT_NOFILE and PROC0_RLIMIT_NPROC in my
kernel sources.
Bruce
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