3 ms·

Which is to say, /var/ is writable when they do it. This business of /var/ not being writable early enough is probably to do with the wonderful complexities of

Which is to say, /var/ is writable when they do it. This business of /var/ not being writable early enough is probably to do with the wonderful complexities of modern Linux, and is just not a problem that OpenBSD has.

asveikau 7y ago
This is a fancy way of saying it's systemd's fault. (/s)
bonzini 7y ago
What if a filesystem error forces /var (or whichever mount point hosts the entropy seed) to remain read-only and seed is never replaced? Seems like unlike systemd the BSDs are fine with crediting entropy even if it has been used already in a previous boot. That's wrong though.
- throw0101a 7y ago
  > Seems like unlike systemd the BSDs are fine with crediting entropy even if it has been used already in a previous boot. FreeBSD runs a regular cron job so that there are multiple files. If /var goes R-O, you still have a bunch of files from when it wasn't and they are not the same as on initial boot (assuming that (a) /var was mounted R-W at some point, and (b) cron managed to run as well). Also, on shutdown there is an attempt to write 4096B to both /entropy and /boot/entropy: * https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random?revision=348122&view=markup https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random?... Further, all of these various seed files are not the only sources of entropy (timers, RDRAND, etc).
  - bonzini 7y ago
    > (assuming that (a) /var was mounted R-W at some point Not a good assumption if the initial r/w mount is the one that fails...
    - throw0101a 7y ago
      If the initial /var (or /) is broken, then one has bigger problems and probably has to go in manually to fix things. But for >99% of cases where the system comes up cleanly, and runs cleanly for a period of time, you'll have a bunch of seed files ready to go for the next boot. This configuration optimizes for the common case.
throw0101a 7y ago
> Which is to say, /var/ is writable when they do it. They also do it at shutdown, before /var is R/O or unmounted. One can also have multiple files, and have a regular cron job that replaces one of them occasionally while the system is running. This is what the FreeBSD script does. * https://svnweb.freebsd.org/base/head/libexec/save-entropy/ https://svnweb.freebsd.org/base/head/libexec/save-entropy/ * https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random Other systems have solved this problem, so I'm not sure why all the high drama with Linux.

asveikau 7y ago

This is a fancy way of saying it's systemd's fault. (/s)

bonzini 7y ago

What if a filesystem error forces /var (or whichever mount point hosts the entropy seed) to remain read-only and seed is never replaced? Seems like unlike systemd the BSDs are fine with crediting entropy even if it has been used already in a previous boot. That's wrong though.

throw0101a 7y ago
> Seems like unlike systemd the BSDs are fine with crediting entropy even if it has been used already in a previous boot. FreeBSD runs a regular cron job so that there are multiple files. If /var goes R-O, you still have a bunch of files from when it wasn't and they are not the same as on initial boot (assuming that (a) /var was mounted R-W at some point, and (b) cron managed to run as well). Also, on shutdown there is an attempt to write 4096B to both /entropy and /boot/entropy: * https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random?revision=348122&view=markup https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random?... Further, all of these various seed files are not the only sources of entropy (timers, RDRAND, etc).
- bonzini 7y ago
  > (assuming that (a) /var was mounted R-W at some point Not a good assumption if the initial r/w mount is the one that fails...
  - throw0101a 7y ago
    If the initial /var (or /) is broken, then one has bigger problems and probably has to go in manually to fix things. But for >99% of cases where the system comes up cleanly, and runs cleanly for a period of time, you'll have a bunch of seed files ready to go for the next boot. This configuration optimizes for the common case.

throw0101a 7y ago

> Which is to say, /var/ is writable when they do it. They also do it at shutdown, before /var is R/O or unmounted. One can also have multiple files, and have a regular cron job that replaces one of them occasionally while the system is running. This is what the FreeBSD script does. * https://svnweb.freebsd.org/base/head/libexec/save-entropy/ https://svnweb.freebsd.org/base/head/libexec/save-entropy/ * https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random Other systems have solved this problem, so I'm not sure why all the high drama with Linux.