The systemd pstore service archives the contents of /sys/fs/pstore
upon boot so that there is room for a subsequent dump. The issue is
that while the service is present, the kernel still needs to be
configured to write data into the pstore. The kernel has two
parameters, crash_kexec_post_notifiers and printk.always_kmsg_dump,
that control writes into pstore.
The crash_kexec_post_notifiers parameter enables the kernel to write
dmesg (including stack trace) into pstore upon a panic, and
printk.always_kmsg_dump parameter enables the kernel to write dmesg
upon a shutdown (shutdown, reboot, halt).
As it stands today, these parameters are not managed/manipulated by
the systemd pstore service, and are solely reliant upon the user [to
have the foresight] to set them on the kernel command line at boot, or
post boot via sysfs. Furthermore, the user would need to set these
parameters in a persistent fashion so that that they are enabled on
subsequent reboots.
This patch introduces the setting of these two kernel parameters via
the systemd tmpfiles technique.
For low memory machines (256MB), 10% of RAM for /run may not be enough for
re-exec of PID1 because 16MB of free space is required and /run may already
contain something.
When setting flow control attributes of an interface we first acquire
the current settings and then add in the new settings before applying
them again. This only works on interfaces that implement the ethtool
ioctls. on others we'll see an ugly "Could not set flow control of"
message, simply because we issue the SIOCETHTOOL ioctl once, for getting
the data. In particular we'll get it for the "lo" interface all the
time, which sucks hard. Let's get rid of it.
Fixes: oss-fuzz#22208
```
test/fuzz/fuzz-calendarspec/oss-fuzz-22208... ../src/shared/calendarspec.c:666:48: runtime error: signed integer overflow: 2147000000 + 1000000 cannot be represented in type 'int'
#0 0x7f0b9f6cc56a in prepend_component ../src/shared/calendarspec.c:666
#1 0x7f0b9f6cd03a in parse_chain ../src/shared/calendarspec.c:718
#2 0x7f0b9f6cea1c in parse_calendar_time ../src/shared/calendarspec.c:845
#3 0x7f0b9f6d1397 in calendar_spec_from_string ../src/shared/calendarspec.c:1084
#4 0x401570 in LLVMFuzzerTestOneInput ../src/fuzz/fuzz-calendarspec.c:17
#5 0x401ae0 in main ../src/fuzz/fuzz-main.c:39
#6 0x7f0b9e31b1a2 in __libc_start_main (/lib64/libc.so.6+0x271a2)
#7 0x40122d in _start (/home/fsumsal/repos/systemd/build/fuzz-calendarspec+0x40122d)
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../src/shared/calendarspec.c:666:48 in
```
Prompted by the discussions in #15180.
This is a bit more complex than I hoped, since for PID 1 we need to pass
in the synethetic environment block in we generate on demand.
It's easy to add, and should be pretty useful, in particular as in
AssertPathIsEncrypted= as it can be used for checking that
some path is encrypted before some service is invoked that might want to
place secure material there.
Link groups are similar to port ranges found in managed switches.
You can add network interfaces to a numbered group and perform operations
on all the interfaces from that group at once.
Let's go one step further and upgrade implicitly. Usually =syslog
assignments are historic artifacts only. Let's upgrade the lines
automatically, and politely suggest people update their unit
files/configuration (and drop the lines altogether, without
replacement).
Fixes: #15807
This adds --empty=create and --size= for creating loopback files from
scratch of a specified size, or growing loopback files to the specified
size when they already exist.
This is useful when operating on disk image files, as a manual
invocation of fallocate(1) becomes unnecessary.
While investigating why some of my netlink calls would timeout I
stumbled upon the definition of the max write queue length. Finding this
constant made me believe we still had a write queue in the code - which
isn't true. The netlink write queue code was removed in #189.
- If length of formatted string >= LONG_LINE_MAX then return -ENOBUFS
- Normal Case:
- length of formatted string < POSIX defined LINE_MAX
- Allocate sbuf to accomodate the message
- Rare case:
- LINE_MAX < length of formatted string < LONG_LINE_MAX
- Allocate the required length using alloca()
Let's use size_t for numbers of entries in memory.
Let's use const wherever appropriate.
Drop `_server` suffix from function name where we don't have it for
similar other cases.
