Sometimes these function may set errno to unexpected values like EAGAIN.
This causes confusion. Avoid that by using our own wrappers that retry
in that case. For example, in rhbz#1797915 we have failures like:
errno = 0;
v = g_ascii_strtoll ("10", 0, &end);
if (errno != 0)
g_assert_not_reached ();
as g_ascii_strtoll() would return 10, but also set errno to EAGAIN.
Work around that by using wrapper functions that retry. This certainly
should be fixed in glib (or glibc), but the issues are severe enough to
warrant a workaround.
Note that our workarounds are very defensive. We only retry 2 times, if
we get an unexpected errno value. This is in the hope to recover from
a spurious EAGAIN. It won't recover from other errors.
https://bugzilla.redhat.com/show_bug.cgi?id=1797915
(cherry picked from commit 7e49f4a199)
NMTST_SWAP() used memcpy() for copying the value, while NM_SWAP() uses
a temporary variable with typeof(). I think the latter is preferable.
Also, the macro is essentially doing the same thing.
(cherry picked from commit 6f9a478b7d)
Currently if an error is encountered during a send() of a message, the
client fails and there is no possibility of recover, since no timers
are armed after a failed event dispatch. An easy way to reproduce a
failure is to add a firewall rule like:
iptables -A OUTPUT -p udp --dport 67 -j REJECT
which makes the send() fail with EPERM during the renew. In such case,
the client should continue (failing) until it reaches the rebind phase
at T2, when it will be able to renew the lease using the packet
socket.
In general, a failure to send a packet should not cause the failure of
the client.
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/merge_requests/419https://bugzilla.redhat.com/show_bug.cgi?id=1806516
(cherry picked from commit 5a7b83ea0a)
The interface name might come from the command line or from a filename
(like during nm_vpn_wireguard_import()). It's not clear that this
is valid UTF-8. Asserting against that requires the caller to ensure
that the encoding is valid. That is cumbersome, especially since we anyway
check. Just report a regular error.
(cherry picked from commit 82fb8b00b4)
quoting 'man ovs-vswitchd.conf.db':
"The name must be alphanumeric and must not contain forward or backward
slashes."
OVS actually accepts a wider range of chars (all printable UTF-8 chars),
NetworkManager restricts this to ASCII char as it's a safer option for
now since OVS is not well documented on this matter.
https://bugzilla.redhat.com/show_bug.cgi?id=1788432
Fixes: e7d72a14f6 ('libnm-core: use different ifname validation function for OVS bridges, ports and interfaces')
(cherry picked from commit ed5a647ad1)
The only affected caller is nm_modem_manager_get_modems(), which
is used by NMDeviceBt for DUN connections. This is rather bad.
Fixes: 4154d9618c ('bluetooth: refactor BlueZ handling and let NMBluezManager cache ObjectManager data')
Fixes: e688e70b37 ('shared: add nm_utils_hash_values_to_array() helper')
(cherry picked from commit 037507f790)
Move the body of nm_utils_is_valid_iface_name() to
nm_utils_ifname_valid_kernel() so that it's shared between NM and
clients.
(cherry picked from commit 550f538564)
G_SOURCE_FUNC has attribute GLIB_AVAILABLE_MACRO_IN_2_58, which means
that the compiler will emit a warning when GLIB_VERSION_MAX_ALLOWED <
GLIB_VERSION_2_58. We currently define GLIB_VERSION_MAX_ALLOWED as
GLIB_VERSION_2_40. Redefine the macro to fix the following build error
when using glib >= 2.63.5 (the version in which the attribute was
added):
CC shared/nm-glib-aux/libnm_glib_aux_la-nm-shared-utils.lo
shared/nm-glib-aux/nm-shared-utils.c: In function ‘nm_g_unix_fd_source_new’:
shared/nm-glib-aux/nm-shared-utils.c:3679:13: error: Not available before [-Werror]
3679 | g_source_set_callback (source, G_SOURCE_FUNC (source_func), user_data, destroy_notify);
Fixes: 9c5741ccd2 ('shared/nm-glib: add compat implementation for G_SOURCE_FUNC()')
(cherry picked from commit 7f801685b2)
Properly initialize 'overload' when the space in the file section
ends.
shared/n-dhcp4/src/n-dhcp4-outgoing.c: In function ‘n_dhcp4_outgoing_append’:
shared/n-dhcp4/src/n-dhcp4-outgoing.c:198:17: error: ‘overload’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
(cherry picked from commit b2620e798a)
Move back to INIT state after the lease expires, as per section 4.4.5
of RFC 2131. Previously the client just moved to EXPIRED, closed the
connection and cleared the probe, leaving to the caller of the library
the choice to create a new client instance and to start from
scratch. However, it seems more useful that the client, once
initialized, always tries to get a lease even after an expiration.
(cherry picked from commit 182a8021f3)
If the server sends a packet with multiple instances of the same
option, they are concatenated during n_dhcp4_incoming_linearize() and
evaluated as a single option as per section 7 of RFC 3396.
However, there are broken server implementations that send
self-contained options in multiple copies. They are reassembled to
form a single instance by the nettools client, which then fails to
parse them because they have a length greater than the expected one.
This problem can be reproduced by starting a server with:
dnsmasq --bind-interfaces --interface veth1 -d
--dhcp-range=172.25.1.100,172.25.1.200,1m
--dhcp-option=54,172.25.1.1
In this way dnsmasq sends a duplicate option 54 (server-id) when the
client requests it in the 'parameter request list' option, as
dhcp=systemd and dhcp=nettools currently do.
While this is a violation of the RFC by the server, both isc-dhcp and
systemd-networkd client implementations have mechanisms to deal with
this situation. dhclient simply takes the first bytes of the
aggregated option. systemd-networkd doesn't follow RFC 3396 and
doesn't aggregate multiple options; it considers only the last
occurrence of each option.
Change the parsing code to accept options that are longer than
necessary.
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/issues/324
(cherry picked from commit 1cbf9d22a5)
The latter requires __auto_type which is not available in GCC versions
older than 4.9. Fix the following compile error on RHEL 7.8:
CC src/src_libNetworkManagerBase_la-NetworkManagerUtils.lo
shared/n-dhcp4/src/n-dhcp4-c-probe.c: In function 'n_dhcp4_client_probe_transition_nak':
shared/n-dhcp4/src/n-dhcp4-c-probe.c:1008:17: error: unknown type name '__auto_type'
probe->ns_nak_restart_delay = c_clamp(probe->ns_nak_restart_delay * 2,
^
shared/n-dhcp4/src/n-dhcp4-c-probe.c:1008:17: error: unknown type name '__auto_type'
shared/n-dhcp4/src/n-dhcp4-c-probe.c:1008:17: error: unknown type name '__auto_type'
Fixes: 218782a9a3 ('n-dhcp4: restart the transaction after a NAK')
(cherry picked from commit 3a9b069c41)
It is not enough to set the INIT state after a NAK; a timeout
(ns_deferred) must be set so that it is added to the event fd. The
client retries immediately the first time, so that in the successful
case it gets an address quickly. To avoid flooding the network in case
of servers always replying with NAKs, next attempts are done with
intervals from 2 seconds to 5 minutes using exponential backoff. See
also systemd commit [1].
[1] 1d1a3e0afbhttps://gitlab.freedesktop.org/NetworkManager/NetworkManager/issues/325
(cherry picked from commit 218782a9a3)
When the client enters the INIT state, it calls listen() on the
connection connection to create the packet socket. However, if the
client is coming from the REBOOTING state after a NAK, the connection
is already in the listening state; do nothing in such case.
(cherry picked from commit 4bcdc3c1eb)
Instead of terminating the program when the dispatch function returns
an invalid return code, log an error message and convert the error
code to a valid, generic one.
https://bugs.archlinux.org/task/64880
(cherry picked from commit 36f8822c9b)
After t1, the client tries to renew the lease by contacting via the
udp socket the server specified in the server-id option. If this
fails, after t2 it tries to contact any server using broadcast. For
this to work, the packet socket must be used.
(cherry picked from commit f860e929c0)
Currently the client always starts from the INIT state (i.e. sending a
discover message). If a requested-ip was specified by the caller, it
is added as an option in the discover.
It was reported that some DHCP servers don't respond to discover
messages with the requested-ip option set [1][2].
The RFC allows to skip the discover by entering the INIT-REBOOT state
and starting directly with a broadcast request message containing the
requested IP address. Implement that.
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1781856
[2] https://gitlab.freedesktop.org/NetworkManager/NetworkManager/issues/310
(cherry picked from commit af03b77980)
Found by covscan:
NetworkManager-1.22.0/shared/nm-glib-aux/nm-dbus-aux.c:361:
missing_va_end: va_end was not called for "ap".
Fixes: ce36494c0a ('shared: add nm_dbus_error_is() helper')
(cherry picked from commit 0de4fd6ebc)
"nm-glib-aux/nm-logging-fwd.h" provides macros like _LOGD() to be reused
by various parts which implement logging (by defining _NMLOG() accordingly).
libnm also has logging, however it uses different logging levels
aside LOGD_DEBUG.
Instead, implement _LOGD() using a define _LOGL_DEBUG, so that libnm can
redefine thos _LOGL_DEBUG defines and use the _LOGD() macro.
(cherry picked from commit 1b00fd2fd2)
RHEL7 supports clock_gettime(CLOCK_BOOTIME), but it does not support
timerfd_create(CLOCK_BOOTIME). Creating a timerfd will fail with EINVAL.
Fallback to CLOCK_MONOTONIC.
Compare this to n-acd which also has compatibility code to fallback to
CLOCK_MONOTONIC. However when n-acd falls back to CLOCK_MONOTONIC, it uses
monotonic clock also for clock_gettime().
For n-dhcp4, the timestamps are also exposed in the public API
(n_dhcp4_client_lease_get_lifetime()). Hence, for timestamps n-dhcp4
still uses and requires clock_gettime(CLOCK_BOOTIME). Only the internal
timeout handling with the timerfd falls back to CLOCK_MONOTONIC.
https://github.com/nettools/n-dhcp4/pull/13https://gitlab.freedesktop.org/NetworkManager/NetworkManager/merge_requests/362
(cherry picked from commit a1771c738d)
Otherwise, other applications cannot bind to port 0.0.0.0:68 at the same time.
This is for example what dhclient wants to do. So even when running
dhclient on another, unrelated interface, it would fail to bind the UDP
socket and quit.
Note that also systemd-networkd's DHCPv4 client sets this socket option.
Presumably for the same reasons.
Signed-off-by: Thomas Haller <thaller@redhat.com>
https://github.com/nettools/n-dhcp4/pull/12
(cherry picked from commit 53b74bc614)
inet_aton() also supports IPv4 addresses in octal (with a leading '0')
or where not all 4 digits of the address are present.
Add nm_utils_parse_inaddr_bin_full() to optionally fallback to
parse the address with inet_aton().
Note taht inet_aton() also supports all crazy formats, including
ignoring trailing garbage after a whitespace. We don't want to accept
that in general.
Note that even in legacy format we:
- accept everything that inet_pton() would accept
- additionally, we also accept some forms which inet_aton() would
accept, but not all.
That means, the legacy format that we accept is a superset of
inet_pton() and a subset of inet_aton(). Which is desirable.
(cherry picked from commit 8fbf67d138)
Do another import, shortly before re-release.
There are no actual changes, but as always: to find out
that there are no changes requires large part of the work of
just doing the reimport.
Also, systemd import branch was rebased recently, that means
git-merge does not get this reimport right automatically (because
it thinks that the changes on master should be reverted). Hence,
this reimport required more care. Do it while there are few
changes.
We have our NM specific logging and log levels. Maybe we should
not have that, and instead only rely on syslog (like systemd)
or glog(). Anyway, currently we have one way and it makes sense
that this is also used outside from "src".
Move the helper function to parse log levels from string to
"nm-logging-base.h" so that we can use the same logging levels
outside of core.
This moves code that is currently GPL2+ licensed to
LGPL2.1+. However as far as I see, this code was entirely written
by Red Hat employees who would not object with this change. Also,
it's as obvious and trivial as it gets.
We have "nm-logging-fwd.h", which (as the name implies) is header-only.
Add instead a "nm-logging-base.c", which also contains implementation for
logging functions that are not only useful under "src/nm-logging.c"
No longer use GDBusObjectMangaerClient and gdbus-codegen generated classes
for the NMClient cache. Instead, use GDBusConnection directly and a
custom implementation (NMLDBusObject) for caching D-Bus' ObjectManager
data.
CHANGES
-------
- This is a complete rework. I think the previous implementation was
difficult to understand. There were unfixed bugs and nobody understood
the code well enough to fix them. Maybe somebody out there understood the
code, but I certainly did not. At least nobody provided patches to fix those
issues. I do believe that this implementation is more straightforward and
easier to understand. It removes a lot of layers of code. Whether this claim
of simplicity is true, each reader must decide for himself/herself. Note
that it is still fairly complex.
- There was a lingering performance issue with large number of D-Bus
objects. The patch tries hard that the implementation scales well. Of
course, when we cache N objects that have N-to-M references to other,
we still are fundamentally O(N*M) for runtime and memory consumption (with
M being the number of references between objects). But each part should behave
efficiently and well.
- Play well with GMainContext. libnm code (NMClient) is generally not
thread safe. However, it should work to use multiple instances in
parallel, as long as each access to a NMClient is through the caller's
GMainContext. This follows glib's style and effectively allows to use NMClient
in a multi threaded scenario. This implies to stick to a main context
upon construction and ensure that callbacks are only invoked when
iterating that context. Also, NMClient itself shall never iterate the
caller's context. This also means, libnm must never use g_idle_add() or
g_timeout_add(), as those enqueue sources in the g_main_context_default()
context.
- Get ordering of messages right. All events are consistently enqueued
in a GMainContext and processed strictly in order. For example,
previously "nm-object.c" tried to combine signals and emit them on an
idle handler. That is wrong, signals must be emitted in the right order
and when they happen. Note that when using GInitable's synchronous initialization
to initialize the NMClient instance, NMClient internally still operates fully
asynchronously. In that case NMClient has an internal main context.
- NMClient takes over most of the functionality. When using D-Bus'
ObjectManager interface, one needs to handle basically the entire state
of the D-Bus interface. That cannot be separated well into distinct
parts, and even if you try, you just end up having closely related code
in different source files. Spreading related code does not make it
easier to understand, on the contrary. That means, NMClient is
inherently complex as it contains most of the logic. I think that is
not avoidable, but it's not as bad as it sounds.
- NMClient processes D-Bus messages and state changes in separate steps.
First NMClient unpacks the message (e.g. _dbus_handle_properties_changed()) and
keeps track of the changed data. Then we update the GObject instances
(_dbus_handle_obj_changed_dbus()) without emitting any signals yet. Finally,
we emit all signals and notifications that were collected
(_dbus_handle_changes_commit()). Note that for example during the initial
GetManagedObjects() reply, NMClient receive a large amount of state at once.
But we first apply all the changes to our GObject instances before
emitting any signals. The result is that signals are always emitted in a moment
when the cache is consistent. The unavoidable downside is that when you receive
a property changed signal, possibly many other properties changed
already and more signals are about to be emitted.
- NMDeviceWifi no longer modifies the content of the cache from client side
during poke_wireless_devices_with_rf_status(). The content of the cache
should be determined by D-Bus alone and follow what NetworkManager
service exposes. Local modifications should be avoided.
- This aims to bring no API/ABI change, though it does of course bring
various subtle changes in behavior. Those should be all for the better, but the
goal is not to break any existing clients. This does change internal
(albeit externally visible) API, like dropping NM_OBJECT_DBUS_OBJECT_MANAGER
property and NMObject no longer implementing GInitableIface and GAsyncInitableIface.
- Some uses of gdbus-codegen classes remain in NMVpnPluginOld, NMVpnServicePlugin
and NMSecretAgentOld. These are independent of NMClient/NMObject and
should be reworked separately.
- While we no longer use generated classes from gdbus-codegen, we don't
need more glue code than before. Also before we constructed NMPropertiesInfo and
a had large amount of code to propagate properties from NMDBus* to NMObject.
That got completely reworked, but did not fundamentally change. You still need
about the same effort to create the NMLDBusMetaIface. Not using
generated bindings did not make anything worse (which tells about the
usefulness of generated code, at least in the way it was used).
- NMLDBusMetaIface and other meta data is static and immutable. This
avoids copying them around. Also, macros like NML_DBUS_META_PROPERTY_INIT_U()
have compile time checks to ensure the property types matches. It's pretty hard
to misuse them because it won't compile.
- The meta data now explicitly encodes the expected D-Bus types and
makes sure never to accept wrong data. That would only matter when the
server (accidentally or intentionally) exposes unexpected types on
D-Bus. I don't think that was previously ensured in all cases.
For example, demarshal_generic() only cared about the GObject property
type, it didn't know the expected D-Bus type.
- Previously GDBusObjectManager would sometimes emit warnings (g_log()). Those
probably indicated real bugs. In any case, it prevented us from running CI
with G_DEBUG=fatal-warnings, because there would be just too many
unrelated crashes. Now we log debug messages that can be enabled with
"LIBNM_CLIENT_DEBUG=trace". Some of these messages can also be turned
into g_warning()/g_critical() by setting LIBNM_CLIENT_DEBUG=warning,error.
Together with G_DEBUG=fatal-warnings, this turns them into assertions.
Note that such "assertion failures" might also happen because of a server
bug (or change). Thus these are not common assertions that indicate a bug
in libnm and are thus not armed unless explicitly requested. In our CI we
should now always run with LIBNM_CLIENT_DEBUG=warning,error and
G_DEBUG=fatal-warnings and to catch bugs. Note that currently
NetworkManager has bugs in this regard, so enabling this will result in
assertion failures. That should be fixed first.
- Note that this changes the order in which we emit "notify:devices" and
"device-added" signals. I think it makes the most sense to emit first
"device-removed", then "notify:devices", and finally "device-added"
signals.
This changes behavior for commit 52ae28f6e5 ('libnm: queue
added/removed signals and suppress uninitialized notifications'),
but I don't think that users should actually rely on the order. Still,
the new order makes the most sense to me.
- In NetworkManager, profiles can be invisible to the user by setting
"connection.permissions". Such profiles would be hidden by NMClient's
nm_client_get_connections() and their "connection-added"/"connection-removed"
signals.
Note that NMActiveConnection's nm_active_connection_get_connection()
and NMDevice's nm_device_get_available_connections() still exposes such
hidden NMRemoteConnection instances. This behavior was preserved.
NUMBERS
-------
I compared 3 versions of libnm.
[1] 962297f908, current tip of nm-1-20 branch
[2] 4fad8c7c64, current master, immediate parent of this patch
[3] this patch
All tests were done on Fedora 31, x86_64, gcc 9.2.1-1.fc31.
The libraries were build with
$ ./contrib/fedora/rpm/build_clean.sh -g -w test -W debug
Note that RPM build already stripped the library.
---
N1) File size of libnm.so.0.1.0 in bytes. There currently seems to be a issue
on Fedora 31 generating wrong ELF notes. Usually, libnm is smaller but
in these tests it had large (and bogus) ELF notes. Anyway, the point
is to show the relative sizes, so it doesn't matter).
[1] 4075552 (102.7%)
[2] 3969624 (100.0%)
[3] 3705208 ( 93.3%)
---
N2) `size /usr/lib64/libnm.so.0.1.0`:
text data bss dec hex filename
[1] 1314569 (102.0%) 69980 ( 94.8%) 10632 ( 80.4%) 1395181 (101.4%) 1549ed /usr/lib64/libnm.so.0.1.0
[2] 1288410 (100.0%) 73796 (100.0%) 13224 (100.0%) 1375430 (100.0%) 14fcc6 /usr/lib64/libnm.so.0.1.0
[3] 1229066 ( 95.4%) 65248 ( 88.4%) 13400 (101.3%) 1307714 ( 95.1%) 13f442 /usr/lib64/libnm.so.0.1.0
---
N3) Performance test with test-client.py. With checkout of [2], run
```
prepare_checkout() {
rm -rf /tmp/nm-test && \
git checkout -B test 4fad8c7c64 && \
git clean -fdx && \
./autogen.sh --prefix=/tmp/nm-test && \
make -j 5 install && \
make -j 5 check-local-clients-tests-test-client
}
prepare_test() {
NM_TEST_REGENERATE=1 NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v
}
do_test() {
for i in {1..10}; do
NM_TEST_CLIENT_BUILDDIR="/data/src/NetworkManager" NM_TEST_CLIENT_NMCLI_PATH=/usr/bin/nmcli python3 ./clients/tests/test-client.py -v || return -1
done
echo "done!"
}
prepare_checkout
prepare_test
time do_test
```
[1] real 2m14.497s (101.3%) user 5m26.651s (100.3%) sys 1m40.453s (101.4%)
[2] real 2m12.800s (100.0%) user 5m25.619s (100.0%) sys 1m39.065s (100.0%)
[3] real 1m54.915s ( 86.5%) user 4m18.585s ( 79.4%) sys 1m32.066s ( 92.9%)
---
N4) Performance. Run NetworkManager from build [2] and setup a large number
of profiles (551 profiles and 515 devices, mostly unrealized). This
setup is already at the edge of what NetworkManager currently can
handle. Of course, that is a different issue. Here we just check how
long plain `nmcli` takes on the system.
```
do_cleanup() {
for UUID in $(nmcli -g NAME,UUID connection show | sed -n 's/^xx-c-.*:\([^:]\+\)$/\1/p'); do
nmcli connection delete uuid "$UUID"
done
for DEVICE in $(nmcli -g DEVICE device status | grep '^xx-i-'); do
nmcli device delete "$DEVICE"
done
}
do_setup() {
do_cleanup
for i in {1..30}; do
nmcli connection add type bond autoconnect no con-name xx-c-bond-$i ifname xx-i-bond-$i ipv4.method disabled ipv6.method ignore
for j in $(seq $i 30); do
nmcli connection add type vlan autoconnect no con-name xx-c-vlan-$i-$j vlan.id $j ifname xx-i-vlan-$i-$j vlan.parent xx-i-bond-$i ipv4.method disabled ipv6.method ignore
done
done
systemctl restart NetworkManager.service
sleep 5
}
do_test() {
perf stat -r 50 -B nmcli 1>/dev/null
}
do_test
```
[1]
Performance counter stats for 'nmcli' (50 runs):
456.33 msec task-clock:u # 1.093 CPUs utilized ( +- 0.44% )
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
5,900 page-faults:u # 0.013 M/sec ( +- 0.02% )
1,408,675,453 cycles:u # 3.087 GHz ( +- 0.48% )
1,594,741,060 instructions:u # 1.13 insn per cycle ( +- 0.02% )
368,744,018 branches:u # 808.061 M/sec ( +- 0.02% )
4,566,058 branch-misses:u # 1.24% of all branches ( +- 0.76% )
0.41761 +- 0.00282 seconds time elapsed ( +- 0.68% )
[2]
Performance counter stats for 'nmcli' (50 runs):
477.99 msec task-clock:u # 1.088 CPUs utilized ( +- 0.36% )
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
5,948 page-faults:u # 0.012 M/sec ( +- 0.03% )
1,471,133,482 cycles:u # 3.078 GHz ( +- 0.36% )
1,655,275,369 instructions:u # 1.13 insn per cycle ( +- 0.02% )
382,595,152 branches:u # 800.433 M/sec ( +- 0.02% )
4,746,070 branch-misses:u # 1.24% of all branches ( +- 0.49% )
0.43923 +- 0.00242 seconds time elapsed ( +- 0.55% )
[3]
Performance counter stats for 'nmcli' (50 runs):
352.36 msec task-clock:u # 1.027 CPUs utilized ( +- 0.32% )
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
4,790 page-faults:u # 0.014 M/sec ( +- 0.26% )
1,092,341,186 cycles:u # 3.100 GHz ( +- 0.26% )
1,209,045,283 instructions:u # 1.11 insn per cycle ( +- 0.02% )
281,708,462 branches:u # 799.499 M/sec ( +- 0.01% )
3,101,031 branch-misses:u # 1.10% of all branches ( +- 0.61% )
0.34296 +- 0.00120 seconds time elapsed ( +- 0.35% )
---
N5) same setup as N4), but run `PAGER= /bin/time -v nmcli`:
[1]
Command being timed: "nmcli"
User time (seconds): 0.42
System time (seconds): 0.04
Percent of CPU this job got: 107%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.43
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 34456
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 6128
Voluntary context switches: 1298
Involuntary context switches: 1106
Swaps: 0
File system inputs: 0
File system outputs: 0
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0
[2]
Command being timed: "nmcli"
User time (seconds): 0.44
System time (seconds): 0.04
Percent of CPU this job got: 108%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.44
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 34452
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 6169
Voluntary context switches: 1849
Involuntary context switches: 142
Swaps: 0
File system inputs: 0
File system outputs: 0
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0
[3]
Command being timed: "nmcli"
User time (seconds): 0.32
System time (seconds): 0.02
Percent of CPU this job got: 102%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.34
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 29196
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 5059
Voluntary context switches: 919
Involuntary context switches: 685
Swaps: 0
File system inputs: 0
File system outputs: 0
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0
---
N6) same setup as N4), but run `nmcli monitor` and look at `ps aux` for
the RSS size.
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
[1] me 1492900 21.0 0.2 461348 33248 pts/10 Sl+ 15:02 0:00 nmcli monitor
[2] me 1490721 5.0 0.2 461496 33548 pts/10 Sl+ 15:00 0:00 nmcli monitor
[3] me 1495801 16.5 0.1 459476 28692 pts/10 Sl+ 15:04 0:00 nmcli monitor
We will rework NMClient entirely. Then, the synchronous initialization will also use
the asynchronous code paths. The difference will be that with synchronous initialization,
all D-Bus interaction will be done with an internal GMainContext as current thread default,
and that internal context will run until initialization completes.
Note that even after initialization completes, it cannot be swapped back to the user's
(outer) GMainContext. That is because contexts are essentially the queue for our
D-Bus events, and we cannot swap from one queue to the other in a race
free manner (or a full resync). In other words, the two contexts are not in sync,
so after using the internal context NMClient needs to stick to that (at least, until
the name owner gets lost, which gives an opportunity to resync and switch back to the
user's main context).
We thus need to hook the internal (inner) GMainContext with the user's (outer) context,
so when the user iterates the outer context, events on the inner context get dispatched.
Add nm_utils_g_main_context_create_integrate_source() to create such a GSource for
integrating two contexts.
Note that the use-case here is limited: the integrated, inner main context must
not be explicitly iterated except from being dispatched by the integrating
source. Otherwise, you'd get recursive runs, possible deadlocks and general
ugliness. NMClient must show restrain how to use the inner context while it is
integrated.
