read_line() is a lot more careful and optimized than read_nul_string()
but does mostly the same thing. let's replace the latter by the former,
just with a special flag that toggles between the slightly different EOL
rules if both.
This splits out a bunch of functions from fileio.c that have to do with
temporary files. Simply to make the header files a bit shorter, and to
group things more nicely.
No code changes, just some rearranging of source files.
Now that we don't (mis-)use the env file parser to parse kernel command
lines there's no need anymore to override the used newline character
set. Let's hence drop the argument and just "\n\r" always. This nicely
simplifies our code.
All users of the macro (except for one, in serialize.c), use the macro in
connection with read_line(), so they must include fileio.h. Let's not play
libc games and require multiple header file to be included for the most common
use of a function.
The removal of def.h includes is not exact. I mostly went over the commits that
switch over to use read_line() and add def.h at the same time and reverted the
addition of def.h in those files.
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Let's always write "1 << 0", "1 << 1" and so on, except where we need
more than 31 flag bits, where we write "UINT64(1) << 0", and so on to force
64bit values.
Most our other parsing functions do this, let's do this here too,
internally we accept that anyway. Also, the closely related
load_env_file() and load_env_file_pairs() also do this, so let's be
systematic.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
fputs() writes only first 2048 bytes and fails
to write to /proc when values are larger than that.
This patch adds a new flag to WriteStringFileFlags
that make it possible to disable the buffer under
specific cases.
read_line() is much like getline(), and returns a line read from a
FILE*, of arbitrary sizes. In contrast to gets() it will grow the buffer
dynamically, and in contrast to getline() it will place a user-specified
boundary on the line.
For files which are vital to boot
1. Avoid opening any window where power loss will zero them out or worse.
I know app developers all coded to the ext3 implementation, but
the only formal documentation we have says we're broken if we actually
rely on it. E.g.
* `man mount`, search for `auto_da_alloc`.
* http://www.linux-mtd.infradead.org/faq/ubifs.html#L_atomic_change
* https://thunk.org/tytso/blog/2009/03/15/dont-fear-the-fsync/
2. If we tell the kernel we're interested in writing them to disk, it will
tell us if that fails. So at minimum, this means we play our part in
notifying the user about errors.
I refactored error-handling in `udevadm-hwdb` a little. It turns out I did
exactly the same as had already been done in the `systemd-hwdb` version,
i.e. commit d702dcd.
merge_env_file is a new function, that's like load_env_file, but takes a
pre-existing environment as an input argument. New environment entries are
merged. Variable expansion is performed.
Falling back to the process environment is supported (when a flag is set).
Alternatively this could be implemented as passing an additional fallback
environment array, but later on we're adding another flag to allow braceless
expansion, and the two flags can be combined in one arg, so there's less
stuff to pass around.
There is a slight change in behaviour: the user manager for root will create a
temporary file in /run/systemd, not /tmp. I don't think this matters, but
simplifies implementation.
This adds mkdtemp_malloc() that is a combination of mkdtemp() plus strdup(). It
initializes its return paremeter only if the temporary directory could be
created successfully, so that the parameter is exactly non-NULL when the
directory exists.
rmdir_and_free() and rmdir_and_freep() are also added, and the latter may be
used inside of _cleanup_ for such a directory string variable, to automatically
rmdir() the directory if it is non-NULL when the scope exits.
rmdir_and_free() is similar to the existing rm_rf_and_free() however, is only
removes a single directory and does not operate recursively.
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.
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
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.
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.
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.
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
