This reworks get_process_cmdline() quite substantially, fixing the following:
- Fixes:
a4e3bf4d7a (r66837630)
- The passed max_length is also applied to the "comm" name, if comm_fallback is
set.
- The right thing happens if max_length == 1 is specified
- when the cmdline "foobar" is abbreviated to 6 characters the result is not
"foobar" instead of "foo...".
- trailing whitespace are removed before the ... suffix is appended. The 7
character abbreviation of "foo barz" is hence "foo..." instead of "foo ...".
- leading whitespace are suppressed from the cmdline
- a comprehensive test case is added
Our functions that query /proc/pid/ support using pid==0 to mean
self. get_process_id also seemed to support that, but it was not implemented
correctly: the result should be in *uid, not returned, and also it gave
completely bogus result when called from get_process_gid(). But afaict,
get_process_{uid,gid} were never called with pid==0, so it's not an actual
bug. Remove the broken code to avoid confusion.
If max_length is equal or greater than cmdline length all trailing non-printable
characters are dropped. If max_length is 0 it should do the same.
This should also fix cmdline truncation if the last character is not '\0'.
Fixes#3469.
The current raw_clone function takes two arguments, the cloning flags and
a pointer to the stack for the cloned child. The raw cloning without
passing a "thread main" function does not make sense if a new stack is
specified, as it returns in both the parent and the child, which will fail
in the child as the stack is virgin. All uses of raw_clone indeed pass NULL
for the stack pointer which indicates that both processes should share the
stack address (so you better don't pass CLONE_VM).
This commit refactors the code to not require the caller to pass the stack
address, as NULL is the only sensible option. It also adds the magic code
needed to make raw_clone work on sparc64, which does not return 0 in %o0
for the child, but indicates the child process by setting %o1 to non-zero.
This refactoring is not plain aesthetic, because non-NULL stack addresses
need to get mangled before being passed to the clone syscall (you have to
apply STACK_BIAS), whereas NULL must not be mangled. Implementing the
conditional mangling of the stack address would needlessly complicate the
code.
raw_clone is moved to a separete header, because the burden of including
the assert machinery and sched.h shouldn't be applied to every user of
missing_syscalls.h
Let's make sigkill_wait() take a normal pid_t, and add sigkill_waitp() that
takes a pointer (which is useful for usage in _cleanup_), following the usual
logic we have for this.
This adds a new GetProcesses() bus call to the Unit object which returns an
array consisting of all PIDs, their process names, as well as their full cgroup
paths. This is then used by "systemctl status" to show the per-unit process
tree.
This has the benefit that the client-side no longer needs to access the
cgroupfs directly to show the process tree of a unit. Instead, it now uses this
new API, which means it also works if -H or -M are used correctly, as the
information from the specific host is used, and not the one from the local
system.
Fixes: #2945
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
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.
so far, when we read something from /proc/$PID we would pass on the
ENOENT from the kernel as error, if the process was missing. With this
change we systematically convert this to ESRCH, which is the more
appropriate error code, and what all the other glibc/syscalls like
kill() use.
All code that calls these functions should be fine with this change. In
fact, one invocation of get_process_exe() in bus-creds.c already assumed
ESRCH would be returned if a process is missing, and this assumption is
now validated after the change.