libfdisk appears to return NULL when encountering an empty partition
label, let's handle this sanely, and treat NULL and "" for the current
label as the same, but for the new label as distinct: there NULL means
nothing is set, and "" means an actual empty label.
This is similar to the --image= switch in the other tools, like
systemd-sysusers or systemd-tmpfiles, i.e. it apply the configuration
from the image to the image.
This is particularly useful for downloading minimized GPT image, and
then extending it to the desired size via:
# systemd-repart --image=foo.image --size=5G
Let's have one flag to request that when dissecting an image the
loopback device is made read-only, and another one to request that when
it is mounted to make it read-only. Previously both concepts were always
done read-only together.
(Of course, making the loopback device read-only but mounting it
read-write doesn't make too much sense, but the kernel should catch that
for us, no need to make restrictions from our side there)
Use-case for this: in systemd-repart we'd like to operate on images for
adding partitions. Thus we'd like to have the loopback device writable,
but if we read repart.d/ snippets from it, we want to do that read-only.
This fixes maybe-uninitialized warning:
```
../src/basic/fileio.c: In function ‘chase_symlinks_and_fopen_unlocked’:
../src/basic/fileio.c:1026:19: warning: ‘f’ may be used uninitialized in this function [-Wmaybe-uninitialized]
1026 | *ret_file = f;
| ~~~~~~~~~~^~~
```
As @yuwata correctly points out, this became broken when log_debug()
started returning -EIO. I wanted to preserve this pattern, but it turns
out it is not very widely used, and preserving it would make the whole
thing, already quite complicated, even more complex.
log_debug() is made like log_info() and friends, and returns void.
Let's assert if we ever happen to pass 0 to one of the log functions.
With the preceding commit to return -EIO from log_*(), passing 0 wouldn't
affect the return value any more, but it is still most likely an error.
The unit test code is an exception: we fairly often pass the return value
to print it, before checking what it is. So let's assert that we're not
passing 0 in non-test code. As with the previous check for %m, this is only
done in developer mode. We are depending on external code setting
errno correctly for us, which might not always be true, and which we can't
test, so we shouldn't assert, but just handle this gracefully.
I did a bunch of greps to try to figure out if there are any places where
we're passing 0 on purpose, and couldn't find any.
The one place that failed in tests is adjusted.
About "zerook" in the name: I wanted the suffix to be unambiguous. It's a
single "word" because each of the words in log_full_errno is also meaningful,
and having one term use two words would be confusing.
This is only done in developer mode. It is a pretty rare occurence that we
make this kind of mistake. And even if it happens, the result is just a misleading
error message. So let's only do the check in non-release builds.
This silences some warnigns where gcc thinks that some variables are
unitialized. One particular case:
../src/journal/journald-server.c: In function 'ache_space_refresh':
../src/journal/journald-server.c:136:28: error: 'vfs_avail' may be used uninitialized in this function [-Werror=maybe-uninitialized]
136 | uint64_t vfs_used, vfs_avail, avail;
| ^~~~~~~~~
../src/journal/journald-server.c:136:18: error: 'vfs_used' may be used uninitialized in this function [-Werror=maybe-uninitialized]
136 | uint64_t vfs_used, vfs_avail, avail;
| ^~~~~~~~
cc1: all warnings being treated as errors
which is caused by
d = opendir(path);
if (!d)
return log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR,
errno, "Failed to open %s: %m", path);
if (fstatvfs(dirfd(d), &ss) < 0)
return log_error_errno(errno, "Failed to fstatvfs(%s): %m", path);
For some reason on aarch64 gcc thinks we might return non-negative here. In
principle errno must be set in both cases, but it's hard to say for certain.
So let's make sure that our code flow is correct, even if somebody forgot to
set the global variable somewhere.
