Ludovic Courtès (2019-11-04 18:07:05 +0100) wrote: > Ivan Vilata i Balaguer <i...@selidor.net> skribis: > > > BTW, I ran that under strace and it looks like the read-only remount fails > > after mounting `/var/run/nscd` in the new namespace has succeeded: > > > > $ strace -f unshare -mUr mount --bind -o ro /var/run/nscd /tmp/tt > > […] > > access("/run/mount", R_OK|W_OK) = -1 EACCES (Permission denied) > > mount("/run/nscd", "/tmp/tt", 0x14c25b0, MS_RDONLY|MS_BIND, NULL) = 0 > > mount("none", "/tmp/tt", NULL, MS_RDONLY|MS_REMOUNT|MS_BIND, NULL) = -1 > > EPERM (Operation not permitted) > > write(2, "mount: ", 7mount: ) = 7 > > write(2, "/tmp/tt: filesystem was mounted,"..., 89/tmp/tt: filesystem > > was mounted, but any subsequent operation failed: Unknown error 5005.) = 89 > > write(2, "\n", 1 > > […] > > Weird, why does it remount it? > > What does: > > mount | grep /run
$ mount | grep /run tmpfs on /run type tmpfs (rw,nosuid,nodev,noexec,relatime,size=1641444k,mode=755) […] > returns? I just tried on a Debian 10 image with Linux 4.19.0 and /run > is a tmpfs, which may be the reason why read-only bind-mounts fail (or > at least there’s a bug in that area.) > > Anyway, below is a patch for you to test. Let me know how it goes. :-) > > Thanks, > Ludo’. I applied your patch on top of bf7b08c4, pulled Guix and did successfully start `guix environment -CN`, with network support and all. Cool! `:)` > diff --git a/gnu/system/file-systems.scm b/gnu/system/file-systems.scm > index 6cf6ccc53e..6cdb2b749d 100644 > --- a/gnu/system/file-systems.scm > +++ b/gnu/system/file-systems.scm > @@ -507,7 +507,8 @@ a bind mount." > ;; XXX: On some GNU/Linux systems, /etc/resolv.conf is a > ;; symlink to a file in a tmpfs which, for an unknown > reason, > ;; cannot be bind mounted read-only within the container. > - (writable? (string=? file "/etc/resolv.conf")))) > + (writable? (or (string=? file "/etc/resolv.conf") > + (string=? file "/var/run/nscd"))))) > (cons "/var/run/nscd" %network-configuration-files))) > > (define (file-system-type-predicate type) -- Ivan Vilata i Balaguer -- https://elvil.net/