Even if pressing Ctrl-c after spawning gdb with "coredumpctl gdb" is not really
useful, we should let gdb handle the signal entirely otherwise the user can be
suprised to see a different behavior when gdb is started by coredumpctl vs when
it's started directly.
Indeed in the former case, gdb exits due to coredumpctl being killed by the
signal.
So this patch makes coredumpctl ignore SIGINT as long as gdb is running.
For the user, if the core file is missing or inaccessible, it is
more interesting that the fact that they forgot to pipe to a file.
So delay the failure from the check until after we have verified
that the file or the COREDUMP field are present.
Partially fixes#4161.
Also, error reporting on failure was duplicated. save_core() now
always prints an error message (because it knows the paths involved,
so can the most useful message), and the callers don't have to.
Propagate errors properly, so that if we hit oom or an error in the
journal, the whole command will fail. This is important when using
the output in scripts.
Support the output of multiple values for the same field with -F.
The journal supports that, and our official commands should too, as
far as it makes sense. -F can be used to print user-defined fields
(e.g. somebody could use a TAG field with multiple occurences), so
we should support that too. That seems better than silently printing
the last value found as was done before.
We would iterate trying to match the same field with all possible
field names. Once we find something, cut the loop short, since we
know that nothing else can match.
The column for "present" was easy to miss, especially if somebody had no
coredumps present at all, in which case the column of spaces of width one
wasn't visually distinguished from the neighbouring columns. Replace this
with an explicit text, one of: "missing", "journal", "present", "error".
$ coredumpctl
TIME PID UID GID SIG COREFILE EXE
Mon 2016-09-26 22:46:31 CEST 8623 0 0 11 missing /usr/bin/bash
Mon 2016-09-26 22:46:35 CEST 8639 1001 1001 11 missing /usr/bin/bash
Tue 2016-09-27 01:10:46 CEST 16110 1001 1001 11 journal /usr/bin/bash
Tue 2016-09-27 01:13:20 CEST 16290 1001 1001 11 journal /usr/bin/bash
Tue 2016-09-27 01:33:48 CEST 17867 1001 1001 11 present /usr/bin/bash
Tue 2016-09-27 01:37:55 CEST 18549 0 0 11 error /usr/bin/bash
Also, use access(…, R_OK), so that we can report a present but inaccessible
file different than a missing one.
In 'list', show present also for coredumps stored in the journal.
In 'status', replace "File" with "Storage" line that is always present.
Possible values:
Storage: none
Storage: journal
Storage: /path/to/file (inacessible)
Storage: /path/to/file
Previously the File field be only present if the file was accessible, so users
had to manually extract the file name precisely in the cases where it was
needed, i.e. when coredumpctl couldn't access the file. It's much more friendly
to always show something. This output is designed for human consumption, so
it's better to be a bit verbose.
The call to sd_j_set_data_threshold is moved, so that status is always printed
with the default of 64k, list uses 4k, and coredump retrieval is done with the
limit unset. This should make checking for the presence of the COREDUMP field
not too costly.
Added in 9fe13294a9 (by me :[```), and later obfuscated in d0c8806d4a, if an
uncompressed external file or an internally stored coredump was supposed to be
written to a file descriptor, nothing would be written.
Back when external storage was initially added in 34c10968cb, this mode of
storage was added. This could have made some sense back when XZ compression was
used, and an uncompressed core on disk could be used as short-lived cache file
which does require costly decompression. But now fast LZ4 compression is used
(by default) both internally and externally, so we have duplicated storage,
using the same compression and same default maximum core size in both cases,
but with different expiration lifetimes. Even the uncompressed-external,
compressed-internal mode is not very useful: for small files, decompression
with LZ4 is fast enough not to matter, and for large files, decompression is
still relatively fast, but the disk-usage penalty is very big.
An additional problem with the two modes of storage is that it complicates
the code and makes it much harder to return a useful error message to the user
if we cannot find the core file, since if we cannot find the file we have to
check the internal storage first.
This patch drops "both" storage mode. Effectively this means that if somebody
configured coredump this way, they will get a warning about an unsupported
value for Storage, and the default of "external" will be used.
I'm pretty sure that this mode is very rarely used anyway.
According to its manual page, flags given to mkostemp(3) shouldn't include
O_RDWR, O_CREAT or O_EXCL flags as these are always included. Beyond
those, the only flag that all callers (except a few tests where it
probably doesn't matter) use is O_CLOEXEC, so set that unconditionally.
Beef up the existing var_tmp() call, rename it to var_tmp_dir() and add a
matching tmp_dir() call (the former looks for the place for /var/tmp, the
latter for /tmp).
Both calls check $TMPDIR, $TEMP, $TMP, following the algorithm Python3 uses.
All dirs are validated before use. secure_getenv() is used in order to limite
exposure in suid binaries.
This also ports a couple of users over to these new APIs.
The var_tmp() return parameter is changed from an allocated buffer the caller
will own to a const string either pointing into environ[], or into a static
const buffer. Given that environ[] is mostly considered constant (and this is
exposed in the very well-known getenv() call), this should be OK behaviour and
allows us to avoid memory allocations in most cases.
Note that $TMPDIR and friends override both /var/tmp and /tmp usage if set.
Many subsystems define own pager_open_if_enabled() function which
checks '--no-pager' command line argument and open pager depends
on its value. All implementations of pager_open_if_enabled() are
the same. Let's merger this function with pager_open() from the
shared/pager.c and remove pager_open_if_enabled() from all subsytems
to prevent code duplication.
