This code is trying to do two things: when reading a file with working
st.st_size, detect when the file size changes between the fstat() and our
allocation of the buffer based on the returned size, and the subsequent read().
When reading a file without st.st_size, read up to READ_FULL_BYTES_MAX.
But this second scenario was partially broken: we'd start with size = 4095, and
double the size up to three times, i.e. up to 32767. But we want to read up to
READ_FULL_BYTES_MAX.
So let's listentangle the two cases a bit: if a file returns non-zero st._size,
proceed as before. But if we don't know the size, let's immediately allocate
the buffer of maximum size of READ_FULL_BYTES_MAX. I think that allocating 4MB
and 1MB is going to take pretty much the same time as long as the memory is not
written to, so by allocating 1MB, 2MB, and 4MB, we wouldn't really be saving
anything internally, but wasting time on repeated reads, if the file is long
enough.
Also, don't do the seek if we know we're going to return an error immediately
after.
This should fix reading of any files in /proc, which all have size == 0. In
particular, various files read by coredump might be larger than 32767.
What about /sys? The file there return a fake value, usually 4096. So we'll
allocate a small buffer and read that.
Improve the logging to only print if systemd-oomd killed something. And
also print which cgroup was targeted.
Demote general swap above/pressure above messages to debug.
[zjs: fix some issuelets found in review]
https://bugzilla.redhat.com/show_bug.cgi?id=1944171
This was in F33, systemd-246.13, but the logic in the code didn't change.
Thread 1 (Thread 0x7fb5f0341b80 (LWP 1974)):
№0 selabel_lookup_common (rec=0x0, translating=0, key=0x55f616ac4750 "/run/user/1000/systemd/units/invocation:systemd-tmpfiles-clean.service", type=40960) at label.c:167
'rec' is the handle that we passed.
№1 0x00007fb5f13ae87f in selabel_lookup_raw (rec=<optimized out>, con=con@entry=0x7fffef307380, key=key@entry=0x55f616ac4750 "/run/user/1000/systemd/units/invocation:systemd-tmpfiles-clean.service", type=type@entry=40960) at label.c:256
lr = <optimized out>
'rec' is passed through as is to selabel_lookup_common().
№2 0x00007fb5f1561b2d in selinux_create_file_prepare_abspath (abspath=0x55f616ac4750 "/run/user/1000/systemd/units/invocation:systemd-tmpfiles-clean.service", mode=40960) at ../src/basic/selinux-util.c:368
filecon = 0x0
r = <optimized out>
__PRETTY_FUNCTION__ = "selinux_create_file_prepare_abspath"
__func__ = "selinux_create_file_prepare_abspath"
№3 0x00007fb5f1561ec3 in mac_selinux_create_file_prepare (path=<optimized out>, mode=40960) at ../src/basic/selinux-util.c:431
r = 0
abspath = 0x55f616ac4750 "/run/user/1000/systemd/units/invocation:systemd-tmpfiles-clean.service"
__PRETTY_FUNCTION__ = "mac_selinux_create_file_prepare"
We checked label_hnd != NULL, but then we apparently called
avc_netlink_check_nb(), which reset label_hnd. Yay for global state!
№4 0x00007fb5f1549950 in symlink_atomic_label (from=0x55f6169d8b50 "69a8dcf7a7ac46b29306f2fddbed3edc", to=0x55f616ab8380 "/run/user/1000/systemd/units/invocation:systemd-tmpfiles-clean.service") at ../src/basic/label.c:55
r = <optimized out>
__PRETTY_FUNCTION__ = "symlink_atomic_label"
In the logs:
Mar 29 14:48:44 fedorapad.home systemd[1974]: selinux: avc: received policyload notice (seqno=2)
Mar 29 14:48:44 fedorapad.home systemd[1974]: Failed to initialize SELinux labeling handle: No such file or directory
Mar 29 14:48:44 fedorapad.home systemd[1974]: selinux: avc: received policyload notice (seqno=3)
Mar 29 14:48:44 fedorapad.home systemd[1974]: selinux: avc: received setenforce notice (enforcing=0)
LLD 13 and GNU ld 2.37 support -z start-stop-gc which allows garbage
collection of C identifier name sections despite the __start_/__stop_
references. Simply set the retain attribute so that GCC 11 (if
configure-time binutils is 2.36 or newer)/Clang 13 will set the
SHF_GNU_RETAIN section attribute to prevent garbage collection.
Without the patch, there are linker errors like the following with -z
start-stop-gc.
```
ld: error: undefined symbol: __start_SYSTEMD_BUS_ERROR_MAP
>>> referenced by bus-error.c:93 (../src/libsystemd/sd-bus/bus-error.c:93)
>>> sd-bus_bus-error.c.o:(bus_error_name_to_errno) in archive src/libsystemd/libsystemd_static.a
```
let's make sure we set the "aa" bit in the stub only if we answer with
fully authoritative data. For this ensure:
1. Either all data is synthetic, including all CNAME/DNAME redirects
2. Or all data comes from the local trust anchor or the local zones
(i.e. not the network or the cache)
Follow-up for 4ad017cda5
Coverity was complaining that we don't check the return value, which we stopped
doing in 772e0a76f3.
But it seems that we don't want those calls at all. The test was originally
added with the call in a6ee01caf3, but I don't
see why we should override this. If the user wants to execute the test with
mempool disabled, we shouldn't ignore that.
Coverity CID#1444464, CID#1444466.
We'd proceed rather inefficiently: the initial buffer size was LINE_MAX/2,
i.e. only 1k. We can read 4k at the same cost.
Also, we'd try to allocate 1025, 2049, 4097 bytes, i.e. always one higher than
the power-of-two size. Effectively the allocation would be bigger, and we'd
waste the additional space. So let's allocate aligned to the power-of-two size.
size=4095, 8191, 16383, so we allocate 4k, 8k, 16k.
We'd first assign a value up to SSIZE_MAX, and then immediately check if we
have a value bigger than READ_FULL_BYTES_MAX. This wasn't exactly wrong, but a
bit roundabout. Let's immediately assign the value from the appropriate range
or error out.
Coverity CID#1450973.
This adds generic support for the SetCredential=/LoadCredential= logic
to our password querying infrastructure: if a password is requested by a
program that has a credential store configured via
$CREDENTIALS_DIRECTORY we'll look in it for a password.
The "systemd-ask-password" tool is updated with an option to specify the
credential to look for.
Let's make use of our own credentials infrastructure in our tools: let's
hook up systemd-sysusers with the credentials logic, so that the root
password can be provisioned this way. This is really useful when working
with stateless systems, in particular nspawn's "--volatile=yes" switch,
as this works now:
# systemd-nspawn -i foo.raw --volatile=yes --set-credential=passwd.plaintext-password:foo
For the first time we have a nice, non-interactive way to provision the
root password for a fully stateless system from the container manager.
Yay!
Let's be a bit less strict when setting up credentials: if the service
manager didn't receieve a cred, and we shall propagate it down via
LoadCredentials= don't fail. Fail on all other errors though, as before,
and on explicitly listed paths.
This allows "LoadCredentials=foo" to be used as shortcut for
"LoadCredentials=foo:foo", i.e. it's a very short way to inherit a
credential under its original name from the service manager into a
service.
In bind_remount_one_with_mountinfo() let's handle mount failures
gracefully if the flags already match anyway. This isn't perfect, since
it mixes up superblock and mount point flags, but it's close enough.
And get rid of get_mount_flags() altogether.
(This drops the statvfs() fallback that get_mount_flags() did. That
fallback was incomplete however, and mostly hid errors. Our primary
avenue to get mount flags is /proc/self/mountinfo and we should trust
it, and fix bugs we might encounter with it, but not tape over it.
Dropping the fallback is relevant in particular as it actually returned
mount flags for any path, not just mount points, which was very icky.)
This replaces the "todo" set with a "todo" hash map that stores the
mount flags we found. This makes an explicit call to get_mount_flags()
unncessary, since we have the flags handy right-away, and lowers our
work from O(n^2) to O(n). Nice!
The "done" set is also improved slightly: we'll use more modern ways to
allocate it, via set_ensure_consume(), and freeing-via-hash_ops.
Finally, failures on submount remounts are now handled gracefully,
there are just too many reasons why they might fail, given NFS, autofs,
FUSE which weird access controls, where even root might lack the privs
to do something.
Fixes: #16156
Instead of marking the bind mount read-only right-away, let's just
restart the loop, so that we'll pick it up like any other mount and then
remount like that.
Let's always query one property, check it, and then query the next,
preferring "cheap" ones over "slow" ones (i.e. cheap are the ones we can
check directly, and slow are the ones we need to check with some loop of
some kind).
The various flavours of stat() basically tell us for free if something
is a symlink. If it is, then it's definitely not a mount point. Use
that.
All other inode types can be mount point, just symlinks cannot.
This fixes resetting of initial_jitter_elapsed: the first time the timer
hits after initial_jitter_scheduled is set we need to mark things as
elapsed.
(Also improve log messages around this while we are at it)
