Let's not leak details from src/shared and src/libsystemd into
src/basic, even though you can't actually do anything useful with
just forward declarations from src/shared.
The sd-forward.h header is put in src/libsystemd/sd-common as we
don't have a directory for shared internal headers for libsystemd
yet.
Let's also rename forward.h to basic-forward.h to keep things
self-explanatory.
I noticed similar warnings in many VM boots:
fedora (udev-worker)[475]: sr0: Failed to open device node: No medium found
This particular one is from src/udev/udev-builtin-uaccess.c:125, but I think the
same principle should be used in all places: if we are ignoring errors that the
device has been removed, we should also ignore ENOMEDIUM.
abs() requires including the entirety of stdlib.h just for a single
trivial function. Let's introduce the ABS() macro and use it in header
files instead so we can get rid of stdlib.h transitive includes in header
files in a later commit.
Various functions in log.h are only used by asserts, and there's
enough assertion related stuff in macro.h to justify a separate header
which also makes it easier to avoid circular dependencies.
Let's introduce assert-util.h and an accompanying fundamental header
and move all the assertion related stuff over there. PROJECT_FILE is
moved over to macro.h.
This is useful if the variable is ssize_t and we don't want to trigger a
warning or truncation.
With gcc (gcc-13.2.1-1.fc38.x86_64), the resulting systemd binary is identical,
so I assume that the compiler is able to completely optimize away the type.
We do 'IN_SET(r, -CONST1, -CONST2)', instead of 'IN_SET(-r, CONST1, CONST2)'
because -r is undefined if r is the minimum value (i.e. INT_MIN). But we know
that the constants are small, so their negative values are fine.
This new helper converts libc style syscall return values into
systemd-kernel (actually: kernel style) negative errno values.
It's implemented as macro-like inline function, and propagates return
values >= 0 as themselves and returns -errno for negative error returns.
THis is supposed to be little more than syntactic sugar so that we can
reduce a lot of (short, but still) boilerplate code whever we convert
libc style error handling into our own.
As discussed here:
https://github.com/systemd/systemd/pull/21326#discussion_r748413537
C's strerror() function does not return a "const char *" pointer
for the string. That has historic reasons and C99 even comments
that "[t]he array pointed to shall not be modified by the program".
Make the strerror_safe() wrapper correct this and be more strict
in this regard.
This is modelled after the existing ERRNO_IS_RESOURCES() and in
particular ERRNO_IS_DISCONNECT(). It returns true for all transient
network errors that should be handled like EAGAIN whenever we call
accept() or accept4(). This is per documentation in the accept(2) man
page that explicitly says to do so in the its "RETURN VALUE" section.
The error list we cover is a bit more comprehensive, and based on
existing code of ours. For example EINTR is included too (since we need
that to cover cases where we call accept()/accept4() on a blocking
socket), and of course ERRNO_IS_DISCONNECT() is a bit more comprehensive
than the list in the man page too.
No technical reason, except that later on we want to add a new
ERRNO_IS() which uses the parameter twice and where we want to avoid
double evaluation, and where we'd like to keep things in the same style.
Yu Watanabe
Daan De Meyer
Zbigniew Jędrzejewski-Szmek
Mike Yuan
Lennart Poettering
Luca Boccassi
Thomas Haller