Date: Wed, 03 Apr 2013 11:31:43 +0400 From: Andrey Chernov <ache@freebsd.org> To: Bruce Evans <brde@optusnet.com.au> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org, Xin LI <delphij@FreeBSD.org> Subject: Re: svn commit: r249035 - head/lib/libc/stdlib Message-ID: <515BDADF.8060303@freebsd.org> In-Reply-To: <20130403165736.F819@besplex.bde.org> References: <201304022341.r32NfL8L096954@svn.freebsd.org> <20130403165736.F819@besplex.bde.org>
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On 03.04.2013 11:04, Bruce Evans wrote: >> + mib[0] = CTL_KERN; >> + mib[1] = KERN_ARND; >> + sysctl(mib, 2, (void *)&next, &len, NULL, 0); >> } > > The sysctl() is certain to fail on old kernels (like open of /dev/random > on even older kernels), but there is no longer any error checking or > handling. The contents of `next' on error is indeterminate (not documented > in the man page), but is probably unchanged. Applications can actually > detect this error although though the API doesn't support this, by > using the documented implementation details and assuming that errno > is properly left changed if the syscall fails (set errno to 0 before > the call here and check it after). Even in case sysctl is not fail, kernel's arc4 is very poorly initialized right after the boot. See the comment in the libkern/arc4random.c arc4_randomstir(), it is about device not loaded case, but it is the same even if device is loaded but not harvest enough. NetBSD implementation of kernel's arc4 is different from ours. Really I am _very_ tired to tell people about the problem, to write patches for the problem, etc., so anybody who are interested can search more details and patches in the mail archives.home | help
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