This is useful for situations where an array of FDs is to be passed into
a child process (i.e. by passing it through safe_fork). This function
can be called in the child (before calling exec) to pack the FDs to all
be next to each-other starting from SD_LISTEN_FDS_START (i.e. 3)
The personality() syscall returns a 32-bit value where the top three
bytes are reserved for flags that emulate historical or architectural
quirks, and only the least significant byte reflects the actual
personality we're interested in (in opinionated_personality()).
Use the newly defined mask in the corresponding test as well, otherwise
the test fails on some more "exotic" architectures that set some of the
"quirk" flags:
~# uname -m
armv7l
~# build/test-seccomp
...
/* test_lock_personality */
current personality=0x0
safe_personality(PERSONALITY_INVALID)=0x800000
Assertion '(unsigned long) safe_personality(current) == current' failed at src/test/test-seccomp.c:970, function test_lock_personality(). Aborting.
lockpersonalityseccomp terminated by signal ABRT.
Assertion 'wait_for_terminate_and_check("lockpersonalityseccomp", pid, WAIT_LOG) == EXIT_SUCCESS' failed at src/test/test-seccomp.c:996, function test_lock_personality(). Aborting.
Aborted (core dumped)
See: personality(2) and comments in sys/personality.h
posix_spawnattr_setflags() doesn't OR the input to the current set of flags,
it overwrites them, so we are currently losing POSIX_SPAWN_SETSIGDEF.
Follow-up for: 6ecdfe7d10
This combines safe_fork() with pidref_set_pid().
Eventually we really should switch this to use CLONE_PIDFD, but as that
is not wrapped by glibc yet, it's hard. But this is not crucial anyway,
as a child we just forked off can always safely be referenced also by
PID, given the reaping is under our own control.
A simple test case is added in a follow-up commit.
Sometimes it makes sense to hard kill a client if we die. Let's hence
add a third FORK_DEATHSIG flag for this purpose: FORK_DEATHSIG_SIGKILL.
To make things less confusing this also renames FORK_DEATHSIG to
FORK_DEATHSIG_SIGTERM to make clear it sends SIGTERM. We already had
FORK_DEATHSIG_SIGINT, hence this makes things nicely symmetric.
A bunch of users are switched over for FORK_DEATHSIG_SIGKILL where we
know it's safe to abort things abruptly. This should make some kernel
cases more robust, since we cannot get confused by signal masks or such.
While we are at it, also fix a bunch of bugs where we didn't take
FORK_DEATHSIG_SIGINT into account in safe_fork()
For a given PID and namespace type, this helper function gives the PID
of the leader of the namespace containing the given PID. Use this in
systemd-coredump instead of using the existing get_mount_namespace_leader.
This helper will be used again in a later commit.
glibc does not provide clone() on ia64, only clone2. But only as a
symbol in the shared library, there's no prototype in the gblic
headers, so we have to define it, copied from the manpage.
This wraps glibc's clone() but deals with the 'stack' parameter in a
sensible way. Only supports invocations without CLONE_VM, i.e. when
child is a CoW copy of parent.
Let's be more accurate about what this function does: it checks whether
the underlying reported inode is the same. Internally, this already uses
a better named stat_inode_same() call, hence let's similarly name the
wrapping function following the same logic.
Similar for files_same_at() and path_equal_or_same_files().
No code changes, just some renaming.
Let's be more careful with generating error codes for (expected) error
causes.
This does not introduce new error conditions, it just changes what we
return under specific cases, to make things nicely recognizable in each
case. Most importantly this detects if fdinfo reports a pid of "-1" for
pidfds with processes that are already reaped (and thus have no PID
anymore)
None of our current users care about these error codes, but let's get
this right for the future.
The reason why get_process_cmdline() is so complicated is that we
need to escape and quote arguments for building a single result
string.
That's necessary when we want to log or print the command line.
However, when we want to parse the command line, it is not necessary
that the result is a single string, but can be strv.
This will be used when we parse the command line.
Whenever we're going to close all file descriptors, we tend to close
the log and set it into open when needed mode. When this is done with
the logging target set to LOG_TARGET_AUTO, we run into issues because
for every logging call, we'll check if stderr is connected to the
journal to determine where to send the logging message. This check
obviously stops working when we close stderr, so we settle the log
target before we do that so that we keep using the same logging
target even after stderr is closed.
IN C23, thread_local is a reserved keyword and we shall therefore
do nothing to redefine it. glibc has it defined for older standard
version with the right conditions.
v2 by Yu Watanabe:
Move the definition to missing_threads.h like the way we define e.g.
missing syscalls or missing definitions, and include it by the users.
Co-authored-by: Yu Watanabe <watanabe.yu+github@gmail.com>
Zbigniew Jędrzejewski-Szmek
Lennart Poettering
Adrian Vovk
Frantisek Sumsal
Mike Yuan
Luca Boccassi
Yu Watanabe
Rose
Nick Rosbrook
Joerg Behrmann
OMOJOLA JOSHUA
Daan De Meyer
Cristian RodríguezandYu Watanabe