This is useful so that callers know whether anything at all and how much
was flushed.
This patches through users of this functions to ensure that the return
values > 0 which may be returned now are not propagated in public APIs.
Also, users that ignore the return value are changed to do so explicitly
now.
I'm not sure why this is needed, but apparrently coverity doesn't like
(void)0. With this change, coverity can (almost) build systemd:
CFLAGS='-D_Float128="long double"' meson cov-build -Dman=false && \
CCACHE_DISABLE=1 COVERITY_UNSUPPORTED=1 cov-build --dir cov-int ninja -C cov-build
Patch originially by Marek Cermak <macermak@redhat.com>.
If read_line() returns ENOBFUS this means the line was overly long. When
we use this for checking whether an executable is a script, then this
shouldn't be propagated as-is, but simply as "this is not a script".
This tweaks write_string_stream_ts() in one minor way: when stdio
buffering has been turned off, let's append the newline we shall append
to the buffer we write ourselves so that the kernel only gets one
syscall for the result. When buffering is enabled stdio will take care
of that anyway.
Follow-up for #7750.
Let's call getsockopt() in a loop, so that we can deal correctly with
the label changing while we are trying to read it.
(also, while we are at it, let's make sure that there's always one
trailing NUL byte at the end of the buffer, after all SO_PEERSEC has
zero documentation, and multiple implementing backends, hence let's
better be safe than sorry)
Also, drop UID/GID validity checks from getpeercred() as the kernel will
never pass us invalid UID/GID on userns, but the overflow UID/GID
instead. Add a comment about this.
This ensures that in all threads we fork off in the background in our
code we mask out all signals, so that our thread won't end up getting
signals delivered the main process should be getting.
We always set the signal mask before forking off the thread, so that the
thread has the right mask set from its earliest existance on.
Using wait_for_terminate_and_check() instead of wait_for_terminate()
let's us simplify, shorten and unify the return value checking and
logging of waitid(). Hence, let's use it all over the place.
This new flag will cause safe_fork() to wait for the forked off child
before returning. This allows us to unify a number of cases where we
immediately wait on the forked off child, witout running any code in the
parent after the fork, and without direct interest in the precise exit
status of the process, except recgonizing EXIT_SUCCESS vs everything
else.
This renames wait_for_terminate_and_warn() to
wait_for_terminate_and_check(), and adds a flags parameter, that
controls how much to log: there's one flag that means we log about
abnormal stuff, and another one that controls whether we log about
non-zero exit codes. Finally, there's a shortcut flag value for logging
in both cases, as that's what we usually use.
All callers are accordingly updated. At three occasions duplicate logging
is removed, i.e. where the old function was called but logged in the
caller, too.
First of all, let's return pid_t, which appears to be the correct type
given that we return PIDs, and it#s what fork() uses too.
Most importantly though, flush out our PID cache, so that the call
becomes compatible with our getpid_cached() logic.
We were including gcrypt-util.[ch] by hand in the few places where it
was used. Create a convenience library to avoid compiling the same
files multiple times.
v2:
- use a separate static library instead of mergin into libbasic
gcrypt_util_sources had to be moved because otherwise they appeared twice
in libshared.so halfproducts, causing an error.
-fvisibility=default is added to libbasic, libshared_static so that the symbols
appear properly in the exported symbol list in libshared.
The advantage is that files are not compiled twice. When configured with -Dman=false,
the ninja target list is reduced from 1588 to 1347 targets. The difference in compilation
time is small (<10%). I think this is because of -O0 and ccache and multiple cores, and
in different settings the compilation time could be reduced. The main advantage is that
errors and warnings are not reported twice.
The __get_cpuid() function only calls __cpuid() if __get_cpuid_max()
returns a value that is less than or equal to the leaf value.
In QEMU/KVM, I found that the special hypervisor leaf value (0x40000000U)
is always larger than the value retured by __get_cpuid_max().
Avoid this problem by calling the __cpuid() macro directly once we have
checked the hypervisor bit from leaf 1.
Fixes: d31b0033b7
We make assumptions about the comm name we set via PR_SET_NAME: that it
would reflect the process name, but that's only the case for the main
thread. Moreover, we cache the mmap() region without locking.
Let's hence be safe rather than sorry and support all this only in the
main thread.
It's a relatively small wrapper around safe_fork() now, hence let's move
it over, and make its signature even more alike. Also, set a different
process name for the polkit and askpw agents.
This adds a new safe_fork() wrapper around fork() and makes use of it
everywhere. The new wrapper does a couple of things we previously did
manually and separately in a safer, more correct and automatic way:
1. Optionally resets signal handlers/mask in the child
2. Sets a name on all processes we fork off right after forking off (and
the patch assigns useful names for all processes we fork off now,
following a systematic naming scheme: always enclosed in () – in order
to indicate that these are not proper, exec()ed processes, but only
forked off children, and if the process is long-running with only our
own code, without execve()'ing something else, it gets am "sd-" prefix.)
3. Optionally closes all file descriptors in the child
4. Optionally sets a PR_SET_DEATHSIG to SIGTERM in the child, in a safe
way so that the parent dying before this happens being handled
safely.
5. Optionally reopens the logs
6. Optionally connects stdin/stdout/stderr to /dev/null
7. Debug logs about the forked off processes.
Ultimately, O_CLOEXEC should be off in fd 0, 1, 2, but when we open
/dev/null here it's unlikely to be < 0, and after dupping the fd to 0,
1, 2 we turn off O_CLOEXEC explicitly anyway.
Unless we know that what we are about to open will return 0, 1 or 2 we
should always set O_CLOEXEC in order to be safe to other threads forking
of subprocesses at the wrong moment.
Just a minor tweak, making sure we execute as much as we can of the
funciton, but return the first error instead of the last we encounter.
This is usuelly how we do things when we have functions that continue on
the first error, so let's do it like that here too.
Let's fork off sync() ina process instead of a thread, as a safety
measure. This is beneficial to ensure that the original process can exit
without having to wait for the sync() to finish (note that the kernel
will delay process termination until all threads finished their
syscalls). In case of hanging NFS this increases the chance that PID 1
can safely transition to the "systemd-shutdown" process as the sync() is
initiated early on but definitely not waited for.
