For btrfs, c_f_r() is like BTRFS_IOC_CLONE which we already used, but also
works when max_bytes is set. We do call copy_bytes in coredump code with
max_bytes set, and for large files, so we might see some benefit from using
c_f_r() on btrfs.
For other filesystems, c_f_r() falls back to do_splice_direct(), the same as
sendfile, which we already call, so there shouldn't be much difference.
Tested with test-copy and systemd-coredump on Linux 4.3 (w/o c_f_r)
and 4.5 (w/ c_f_r).
We called sendfile with 16kb (a.k.a. COPY_BUFFER_SIZE) as the maximum
number of bytes to copy. This seems rather inefficient, especially with
large files. Instead, call sendfile with a "large" maximum.
What "large" max means is a bit tricky: current file offset + max
must fit in loff_t. This means that as we call sendfile more than once,
we have to lower the max size.
With this patch, test-copy calls sendfile twice, e.g.:
sendfile(4, 3, NULL, 9223372036854775807) = 738760
sendfile(4, 3, NULL, 9223372036854037047) = 0
The second call is necessary to determine EOF.
I started looking into adding copy_file_range support, and discovered
that we can improve the way we call sendfile:
- sendfile(2) man page is missing an important bit: the number of bytes to
copy cannot be too big (SSIZE_MAX actually), and the description of EINVAL
return code does not mention this either,
- our implementation works but calls sendfile over and over with a small
size, which seems suboptimal.
First add a test which (under strace) can be used to see current behaviour.
In some cases we do not have a udev device when setting up a unit
(certainly the code gracefully handles this). However, we do
then go on to compare the path via path_equal which will assert
if a null value is passed in.
See https://bugs.mageia.org/show_bug.cgi?id=17766
Not sure if this is the correct fix, but it avoids the crash
Currently socket_address_listen() calls mac_selinux_bind() to bind a UNIX
socket and checks its return value and errno for EADDRINUSE. This is not
correct. When there's an SELinux context change made for the new socket,
bind() is not the last function called in mac_selinux_bind(). In that
case the last call is setfscreatecon() from libselinux which can change
errno as it uses access() to check if /proc/thread-self is available.
It fails on kernels before 3.17 and errno is set to ENOENT.
It's safe to check only the return value at it's set to -errno.
If the user specifies an selinux_apifs_context all content created in
the container including /dev/console should use this label.
Currently when this uses the default label it gets labeled user_devpts_t,
which would require us to write a policy allowing container processes to
manage user_devpts_t. This means that an escaped process would be allowed
to attack all users terminals as well as other container terminals. Changing
the label to match the apifs_context, means the processes would only be allowed
to manage their specific tty.
This change fixes a problem preventing RKT containers from working with systemd-nspawn.
name is IFNAMSIZ bytes, but we would copy sizeof(info->name) bytes,
which is IFNAMSIZ + 1. In effect we would go outside of the source
buffer and possibly leave a non-null terminated string in info->name.
CID #1351754.
Zbigniew Jędrzejewski-Szmek