This new helper adds all strings from a Set object as a string array to
a message.
Various places where we have similar code are then ported over to this.
When closing the FILE handle attached to a memstream, it may attempt to
do a realloc() that may fail during OOM situations, in which case we are
left with the buffer pointer pointing to NULL and buffer size > 0. For
example:
```
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
void *realloc(void *ptr, size_t size) {
return NULL;
}
int main(int argc, char *argv[])
{
FILE *f;
char *buf;
size_t sz = 0;
f = open_memstream(&buf, &sz);
if (!f)
return -ENOMEM;
fputs("Hello", f);
fflush(f);
printf("buf: 0x%lx, sz: %lu, errno: %d\n",
(unsigned long) buf, sz, errno);
fclose(f);
printf("buf: 0x%lx, sz: %lu, errno: %d\n",
(unsigned long) buf, sz, errno);
return 0;
}
```
```
$ gcc -o main main.c
$ ./main
buf: 0x74d4a0, sz: 5, errno: 0
buf: 0x0, sz: 5, errno: 0
```
This might do unexpected things if the underlying code expects a valid
pointer to the memstream buffer after closing the handle.
Found by Nallocfuzz.
In various tools and services we have a per-system and per-user concept.
So far we sometimes used a boolean indicating whether we are in system
mode, or a reversed boolean indicating whether we are in user mode, or
the LookupScope enum used by the lookup path logic.
Let's address that, in introduce a common enum for this, we can use all
across the board.
This is mostly just search/replace, no actual code changes.
Return the output of malloc_info() via a file descriptor (in case it
gets large on a busy system). Useful to get live data about memory
usage when it is not possible to run under a profiler from the get-go.
Do not formally register the method, but add a 'hidden' interface
so that it cannot be seen by introspection or by looking at the
object.
(Or when -H is used, since -H and -M are incompatible.)
Note that the slightly unusual form with separate boolean variables (hint_vars,
hint_addr) instead of e.g. a const char* variable to hold the message, because this
way we don't trigger the warning about non-literal format.
In general we almost never hit those asserts in production code, so users see
them very rarely, if ever. But either way, we just need something that users
can pass to the developers.
We have quite a few of those asserts, and some have fairly nice messages, but
many are like "WTF?" or "???" or "unexpected something". The error that is
printed includes the file location, and function name. In almost all functions
there's at most one assert, so the function name alone is enough to identify
the failure for a developer. So we don't get much extra from the message, and
we might just as well drop them.
Dropping them makes our code a tiny bit smaller, and most importantly, improves
development experience by making it easy to insert such an assert in the code
without thinking how to phrase the argument.
This is unfortunately harder to implement than it sounds. The user's bus
is bound a to the user's lifecycle after all (i.e. only exists as long
as the user has at least one PAM session), and the path dynamically (at
least theoretically, in practice it's going to be the same always)
generated via $XDG_RUNTIME_DIR in /run/.
To fix this properly, we'll thus go through PAM before connecting to a
user bus. Which is hard since we cannot just link against libpam in the
container, since the container might have been compiled entirely
differently. So our way out is to use systemd-run from outside, which
invokes a transient unit that does PAM from outside, doing so via D-Bus.
Inside the transient unit we then invoke systemd-stdio-bridge which
forwards D-Bus from the user bus to us. The systemd-stdio-bridge makes
up the PAM session and thus we can sure tht the bus exists at least as
long as the bus connection is kept.
Or so say this differently: if you use "systemctl -M lennart@foobar"
now, the bus connection works like this:
1. sd-bus on the host forks off:
systemd-run -M foobar -PGq --wait -pUser=lennart -pPAMName=login systemd-stdio-bridge
2. systemd-run gets a connection to the "foobar" container's
system bus, and invokes the "systemd-stdio-bridge" binary as
transient service inside a PAM session for the user "lennart"
3. The systemd-stdio-bridge then proxies our D-Bus traffic to
the user bus.
sd-bus (on host) → systemd-run (on host) → systemd-stdio-bridge (in container)
Complicated? Well, to some point yes, but otoh it's actually nice in
various other ways, primarily as it makes the -H and -M codepaths more
alike. In the -H case (i.e. connect to remote host via SSH) a very
similar three steps are used. The only difference is that instead of
"systemd-run" the "ssh" binary is used to invoke the stdio bridge in a
PAM session of some other system. Thus we get similar implementation and
isolation for similar operations.
Fixes: #14580
We return BUS_ERROR_NO_SUCH_UNIT a.k.a. org.freedesktop.systemd1.NoSuchUnit
in various places. In #16813:
Aug 22 06:14:48 core sudo[2769199]: pam_systemd_home(sudo:account): Failed to query user record: Unit dbus-org.freedesktop.home1.service not found.
Aug 22 06:14:48 core dbus-daemon[5311]: [system] Activation via systemd failed for unit 'dbus-org.freedesktop.home1.service': Unit dbus-org.freedesktop.home1.service not found.
Aug 22 06:14:48 core dbus-daemon[5311]: [system] Activating via systemd: service name='org.freedesktop.home1' unit='dbus-org.freedesktop.home1.service' requested by ':1.6564' (uid=0 pid=2769199 comm="sudo su ")
This particular error comes from bus_unit_validate_load_state() in pid1:
case UNIT_NOT_FOUND:
return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_UNIT, "Unit %s not found.", u->id);
It seems possible that we should return a different error, but it doesn't really
matter: if we change pid1 to return a different error, we still need to handle
BUS_ERROR_NO_SUCH_UNIT as in this patch to handle pid1 with current code.
set_put()/set_ensure_put() return 0, not -EEXIST, if the entry is already
found in the set. In this case this does not make any difference, but let's
not confuse the reader.
Patch contains a coccinelle script, but it only works in some cases. Many
parts were converted by hand.
Note: I did not fix errors in return value handing. This will be done separate
to keep the patch comprehensible. No functional change is intended in this
patch.
If we're using a set with _put_strdup(), most of the time we want to use
string hash ops on the set, and free the strings when done. This defines
the appropriate a new string_hash_ops_free structure to automatically free
the keys when removing the set, and makes set_put_strdup() and set_put_strdupv()
instantiate the set with those hash ops.
hashmap_put_strdup() was already doing something similar.
(It is OK to instantiate the set earlier, possibly with a different hash ops
structure. set_put_strdup() will then use the existing set. It is also OK
to call set_free_free() instead of set_free() on a set with
string_hash_ops_free, the effect is the same, we're just overriding the
override of the cleanup function.)
No functional change intended.
The idea is to have a static table that defines the dbus API. The vtable is
defined right next to the interface name and path because they are logically
connected.
This makes the Environment entries more round-trippable: a similar format is
used for input and output. It is certainly more useful for users, because
showing [unprintable] on anything non-trivial makes systemctl show -p Environment
useless in many cases.
Fixes: #14723 and https://bugzilla.redhat.com/show_bug.cgi?id=1525593.
$ systemctl --user show -p Environment run-*.service
Environment=ASDF=asfd "SPACE= "
Environment=ASDF=asfd "SPACE=\n\n\n"
Environment=ASDF=asfd "TAB=\t\\" "FOO=X X"
Many of the convenience functions from sd-bus operate on verbose sets
of discrete strings for destination/path/interface/member.
For most callers, destination/path/interface are uniform, and just the
member is distinct.
This commit introduces a new struct encapsulating the
destination/path/interface pointers called BusAddress, and wrapper
functions which take a BusAddress* instead of three strings, and just
pass the encapsulated strings on to the sd-bus convenience functions.
Future commits will update call sites to use these helpers throwing
out a bunch of repetitious destination/path/interface strings littered
throughout the codebase, replacing them with some appropriately named
static structs passed by pointer to these new helpers.
Change the behavior of string arrays in a bus property map. Previously,
passing the same strv pointer to more than one map entry would result in
the old strv being freed and overwritten. With this change, an existing
strv pointer is appended to.
This is important if we want to create one strv comprised of multiple
dependencies. This makes it so callers don't have to create one strv per
dependency and subsequently merge them into one strv.
If we fail to start polkit, we get a message like
"org.freedesktop.DBus.Error.NameHasNoOwner: Could not activate remote peer.",
which has no meaning for the caller of our StartUnit method. Let's just
return -EACCES.
$ systemctl start apache
Failed to start apache.service: Could not activate remote peer. (before)
Failed to start apache.service: Access denied (after)
Fixes#13865.
Mike Yuan
Zbigniew Jędrzejewski-Szmek
Lennart Poettering
Yu Watanabe
Frantisek Sumsal
Luca Boccassi
David Tardon
Vito Caputo
Kevin Kuehler