On Tue, Dec 18, 2018 at 09:35:59PM +0100, Alexander Tampermeier via blfs-support wrote: > Hi! > > I just built a new LFS 8.3 system and everything seemed to work well at a > first glance. But when trying to install DHCP-4.4.1 according to BLFS 8.3 > stable > (/http://www.linuxfromscratch.org/blfs/view/stable/basicnet/dhcp.html/) the > build aborts due to errors (please see the output below). > > First warnings appear during the build of the bind libraries ("/In file > included from entropy.c:61: ../entropy.c: In function 'entropypool_adddata': > ../entropy.c:327:7: warning: this statement may fall through > [-Wimplicit-fallthrough=] len--;/" and finally the build breaks. >
Warnings are very common with recent gcc versions, and almsot never related to the error(s). In general, all that matters is the first error. But as Bruce said, check the current instructions - our releases are only a snapshot of what we believed worked at that time. > I also recognized that during startup of the machine I get multiple errors > like: > /[ 5.580768] random: udevd: uninitialized urandom read (16 bytes read)/ > /[ 7.752273] random: sshd: uninitialized urandom read (32 bytes read) > /and finally:/ > [ 44.233105] random: crng init done Again, these are warnings. > / > Might it be, that the broken DHCP build is due to some failure of the random > generator as the first warning seems be related to entropy? But I am not not > sure, if the random generator is broken at all. How could I figure out the > core of the build issue? > No, random initialization in the kernel has changed this year, because of vulnerabilities (specifically, generating insufficiently random keys in some situations). Unfortunately, this is now a pain for some machines and VMs. You possibly have a delay while one or more of the bootscripts are looking for, and then using, entropoy - if the machine appears to hang while one or more of the bootscripts is running, try thumping the keyboard. The problem appears more common with SSDs for some reason. A patch was added to the 4.19 (current long-term stable) kernel, adding CONFIG_RANDOM_TRUST_CPU and enabling that should reduce the problem. Most recent machines have hardware rngs (but not my AMD Kaveri and probably not some other low-end CPUs). Alternatively, build haveged and its bootscript (I assume your are on sysv because I think that systemd includes its own dhcp client). > My system is running on VMware and I build several other LFS/BLFS systems > before and there never was an issue with random or DHCP. > Didn't see that until I was trimming the rest : for a VM, use haveged to provide entropy of uncertain quality and ensure a boot in a reasonable time. > By the way: The BLFS book suggests for DHCP to use the "/missing_ipv6/" > patch if the kernel has no IPv6 support. As I could not find this patch in > /http://www.linuxfromscratch.org/patches/blfs/8.3//, I had to compile IPv6 > into the kernel. Is there no such patch anymore available for BLFS 8.3? > The patch is not needed with 4.4. No doubt the lingering reference to it was missed. Happens all the time. Hmm, I see it is still referred to. I don't think it is needed, but I haven't tested dhclient in ages. > -O2 -Wall -Werror -fno-strict-aliasing -I../includes > -I/j/development/dhcp-4.4.1/bind/include -MT discover.o -MD -MP -MF > .deps/discover.Tpo -c -o discover.o discover.c// > //discover.c: In function 'discover_interfaces':// > //discover.c:646:4: error: 'strncpy' output may be truncated copying 15 > bytes from a string of length 15 [-Werror=stringop-truncation]// > // strncpy(tmp->name, info.name, sizeof(tmp->name) - 1);// > // ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~// > //cc1: all warnings being treated as errors// Ah, didn't read the voluminous messages. Need to remove -Werror from CFLAGS. Thread at https://www.mail-archive.com/[email protected]/msg07569.html which I guess was after 8.3 was released. ĸen -- I'm saving up 22 shillings and 10 pence (almost a pound!) per week to buy an ARM-13. http://www.antipope.org/charlie/blog-static/2018/11/brexit-means-brexit.html -- http://lists.linuxfromscratch.org/listinfo/blfs-support FAQ: http://www.linuxfromscratch.org/blfs/faq.html Unsubscribe: See the above information page
