This is a follow-up to 5d2036b5f3, and also makes
the "machinectl clean" verb asynchronous, after all it's little more than a
series of image removals.
The changes required to make this happen are a bit more comprehensive as we
need to pass information about deleted images back to the client, as well as
information about the image we failed on if we failed on one. Hence, create a
temporary file in /tmp, serialize that data into, and read it from the parent
after the operation is complete.
This moves the O_TMPFILE handling from the coredumping code into common library
code, and generalizes it as open_tmpfile_linkable() + link_tmpfile(). The
existing open_tmpfile() function (which creates an unlinked temporary file that
cannot be linked into the fs) is renamed to open_tmpfile_unlinkable(), to make
the distinction clear. Thus, code may now choose between:
a) open_tmpfile_linkable() + link_tmpfile()
b) open_tmpfile_unlinkable()
Depending on whether they want a file that may be linked back into the fs later
on or not.
In a later commit we should probably convert fopen_temporary() to make use of
open_tmpfile_linkable().
Followup for: #3065
Initialize auto variables with cleanup attribute, otherwise we
get a compiler warning with -fexceptions.
./configure CFLAGS='-Wmaybe-uninitialized -fexceptions -O2'
Throughout the tree there's spurious use of spaces separating ++ and --
operators from their respective operands. Make ++ and -- operator
consistent with the majority of existing uses; discard the spaces.
The call combines outputing a string with prefixing it with a space, optionally. This is useful to shorten the logic
for outputing lists of strings, that are space separated.
gcc is confused by the common idiom of
return errno ? -errno : -ESOMETHING
and thinks a positive value may be returned. Replace this condition
with errno > 0 to help gcc and avoid many spurious warnings. I filed
a gcc rfe a long time ago, but it hard to say if it will ever be
implemented [1].
Both conventions were used in the codebase, this change makes things
more consistent. This is a follow up to bcb161b023.
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61846
With this change, the idiom:
r = write_string_file(p, buf, 0);
if (r < 0) {
if (verify_one_line_file(p, buf) > 0)
r = 0;
}
gets reduced to:
r = write_string_file(p, buf, WRITE_STRING_FILE_VERIFY_ON_FAILURE);
i.e. when writing the string fails and the new flag
WRITE_STRING_FILE_VERIFY_ON_FAILURE is specified we'll not return a
failure immediately, but check the contents of the file. If it matches
what we wanted to write we suppress the error and exit cleanly.
Previously, we'd rely on the mtime timestamps of the touch files to see
if our sync/rotation requests were already suppressed. This means we
rely on CLOCK_REALTIME timestamps. With this patch we instead store the
CLOCK_MONOTONIC timestamp *in* the touch files, and avoid relying on
mtime.
This should make things more reliable when the clock or underlying mtime
granularity is not very good.
This also adds warning messages if writing any of the flag files fails.
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
All users of get_status_field() expect the field pattern to occur in
the beginning of a line, and the delimiter is ':'.
Hardcode this into the function, and also skip any whitespace before ':'
to support fields in files like /proc/cpuinfo. Add support for returning
the full field value (currently stops on first whitespace).
Rename the function so it's easier to ensure all callers switch to new
semantics.
Some places invoked fflush() directly with their own manual error
checking, let's unify all that by using fflush_and_check().
This also unifies the general error paths of fflush()+rename() file
writers.
Merge write_string_file(), write_string_file_no_create() and
write_string_file_atomic() into write_string_file() and provide a flags mask
that allows combinations of atomic writing, newline appending and automatic
file creation. Change all users accordingly.
1) never bother with setting the flag for loopback devices
2) if we fail to write the flag due to EROFS (which is likely to happen
in containers where /proc/sys is read-only) or any other error, check
if the flag already has the right value. If so, don't complain.
Closes#469
Torstein Husebø