The `libnm-core` build file has been improved by applying a set of
changes:
- Indentation has been fixed to be consistent.
- Library variable names have been changed to `lib{name}` pattern
following their filename pattern.
- `shared` prefix has been removed from all variables using it.
- Dependencies have been reviewed to store the necessary data.
- The use of the libraries and dependencies created in this file
has been reviewed through the entire source code. This has
required the addition or the removal of different libraries and
dependencies in different targets.
- Some files used directly with the `files` function have been moved
to their nearest path build file because meson stores their full
path seamessly and they can be used anywhere later.
The `nm-default.h` header is used widely in the code by many
targets. This header includes different headers and needs different
libraries depending the compilation flags.
A new set of `*nm_default_dep` dependencies have been created to
ease the inclusion of different directorires and libraries.
This allows cleaner build files and avoiding linking unnecessary
libraries so this has been applied allowing the removal of some
dependencies involving the linking of unnecessary libraries.
The `shared` build file has been improved by applying a set of
changes:
- Indentation has been fixed to be consistent.
- Unused libraries and dependencies have been removed.
- Dependencies have been reviewed to store the necessary data.
- Set of objects used in targets have been grouped together.
- Header files have been removed from sources lists as it's
unnecessary.
- Library variable names have been changed to `lib{name}` pattern
following their filename pattern.
- `shared` prefix has been removed from all variables using it.
- `version_header` its related configuration `version_conf`
variables have been renamed to `nm_version_macro*` following
its input and final file names.
Functions derived from generators as `configure_file`,
`custom_target` and `i18n.merge_file` can use placeholders like
`@BASENAME@` that removes the extension from the input filename
string.
The output string has been replaced by this placeholder that
allows in some cases the use of less variables.
Several points.
- We spawn the dnsmasq process directly. That has several downsides:
- The lifetime of the process is tied to NetworkManager's. When
stopping NetworkManager, we usually also stop dnsmasq. Or we keep
the process running, but later the process is no longer a child process
of NetworkManager and we can only kill it using the pidfile.
- We don't do special sandboxing of the dnsmasq process.
- Note that we want to ensure that only one dnsmasq process is running
at any time. We should track that in a singletone. Note that NMDnsDnsmasq
is not a singleton. While there is only one instance active at any time,
the DNS plugin can be swapped (e.g. during SIGHUP). Hence, don't track the
process per-NMDnsDnsmasq instance, but in a global variable "gl_pid".
- Usually, when NetworkManager quits, it also stops the dnsmasq process.
Previously, we would always try to terminate the process based on the
pidfile. That is wrong. Most of the time, NetworkManager spawned the
process itself, as a child process. Hence, the PID is known and NetworkManager
will get a signal when dnsmasq exits. The only moment when NetworkManager should
use the pidfile, is the first time when checking to kill the previous instance.
That is: only once at the beginning, to kill instances that were
intentionally or unintentionally (crash) left running earlier.
This is now done by _gl_pid_kill_external().
- Previously, before starting a new dnsmasq instance we would kill a
possibly already running one, and block while waiting for the process to
disappear. We should never block. Especially, since we afterwards start
the process also in non-blocking way, there is no reason to kill the
existing process in a blocking way. For the most part, starting dnsmasq
is already asynchronous and so should be the killing of the dnsmasq
process.
- Drop GDBusProxy and only use GDBusConnection. It fully suffices.
- When we kill a dnsmasq instance, we actually don't have to wait at
all. That can happen fully in background. The only pecularity is that
when we restart a new instance before the previous instance is killed,
then we must wait for the previous process to terminate first. Also, if
we are about to exit while killing the dnsmasq instance, we must register
nm_shutdown_wait_obj_*() to wait until the process is fully gone.
Having G_PID_FORMAT macro is useful, but it's only available in
recent glib versions. Add a compat implementation and a test that
our assumptions hold.
The leading underscore has the notion that this would be a private function.
It really isn't, and it would be fine for the user to call it directly.
Just like we have g_slice_free() and g_slice_free1().
I'd like to refactor libnm's caching. Note that cached D-Bus objects
have repeated strings all over the place. For example every object will
have a set of D-Bus interfaces (strings) and properties (strings) and an
object path (which is referenced by other objects). We can save a lot of
redundant strings by deduplicating/interning them. Also, by interning
them, we can compare them using pointer equality.
Add a NMRefString implementation for this.
Maybe an alternative name would be NMInternedString or NMDedupString, because
this string gets always interned. There is no way to create a NMRefString
that is not interned. Still, NMRefString name sounds better. It is ref-counted
after all.
Notes:
- glib has GQuark and g_intern_string(). However, such strings cannot
be unrefered and are leaked indefinitely. It is thus unsuited for
anything but a fixed set of well-known strings.
- glib 2.58 adds GRefString, but we cannot use that because we
currently still use glib 2.40.
There are some differences:
- GRefString is just a typedef to char. That means, the glib API
exposes GRefString like regular character strings.
NMRefString intentionally does that not. This makes it slightly
less convenient to pass it to API that expects "const char *".
But it makes it clear to the reader, that an instance is in fact
a NMRefString, which means it indicates that the string is
interned and can be referenced without additional copy.
- GRefString can be optionally interned. That means you can
only use pointer equality for comparing values if you know
that the GRefString was created with g_ref_string_new_intern().
So, GRefString looks like a "const char *" pointer and even if
you know it's a GRefString, you might not know whether it is
interned. NMRefString is always interned, and you can always
compare it using pointer equality.
- In the past I already proposed a different implementation for a
ref-string. That made different choices. For example NMRefString
then was a typedef to "const char *", it did not support interning
but deduplication (without a global cache), ref/unref was not
thread safe (but then there was no global cache so that two threads
could still use the API independently).
The point is, there are various choices to make. GRefString, the
previous NMRefString implementation and the one here, all have pros and
cons. I think for the purpose where I intend NMRefString (dedup and
efficient comparison), it is a preferable implementation.
Ah, and of course NMRefString is an immutable string, which is a nice
property.
There is really no reason for this to be a macro. Our hash-related
helpers (like nm_hash_update_val()) are macros because they do some
shenigans to accept arguments of different (compile-time) types. But
the arguments for nm_hash_obfuscate_ptr() are well known and expected
of a certain form.
Note that with "-O2" some quick testing shows that the compiler no
longer inlines the function. But I guess that's fine, probably the
compiler knows best anyway.
... and nm_utils_fd_get_contents() and nm_utils_file_set_contents().
Don't mix negative errno return value with a GError output. Instead,
return a boolean result indicating success or failure.
Also, optionally
- output GError
- set out_errsv to the positive errno (or 0 on success)
Obviously, the return value and the output arguments (contents, length,
out_errsv, error) must all agree in their success/failure result.
That means, you may check any of the return value, out_errsv, error, and
contents to reliably detect failure or success.
Also note that out_errsv gives the positive(!) errno. But you probably
shouldn't care about the distinction and use nm_errno_native() either
way to normalize the value.
nm_utils_file_set_contents() is a re-implementation of g_file_set_contents(),
as such it returned merely a boolean success value.
It's sometimes interesting to get the native error code. Let the function
deviate from glib's original g_file_set_contents() and return the error code
(as negative value) instead.
This requires all callers to change. Also, it's potentially a dangerous
change, as this is easy to miss.
Note that nm_utils_file_get_contents() also returns an errno, and
already deviates from g_file_get_contents() in the same way. This patch
resolves at least the inconsistency with nm_utils_file_get_contents().
- add nm_c_list_elem_find_first() macro that takes a predicate
and returns the first match.
This macro has a non-function-like behavior, which we often try to
avoid because macros should behave like functions. In this case it's
however convenient, so let's do it.
Also, despite being non-function-like, it should be pretty hard to
use wrongly.
- rename nm_c_list_elem_find_first() to nm_c_list_elem_find_first_ptr().
When we build n-dhcp4 for NetworkManager we get a compiler warning.
This can also be reproduced by building n-dhcp4 alone:
$ CFLAGS='-Werror=declaration-after-statement' meson build && ninja -C build
...
[36/47] Compiling C object 'src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o'.
FAILED: src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o
ccache cc -Isrc/25a6634@@ndhcp4-private@sta -Isrc -I../src -Isubprojects/c-list/src -I../subprojects/c-list/src -Isubprojects/c-siphash/src -I../subprojects/c-siphash/src -Isubprojects/c-stdaux/src -I../subprojects/c-stdaux/src -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=c11 -g -D_GNU_SOURCE -Werror=declaration-after-statement -fPIC -fvisibility=hidden -fno-common -MD -MQ 'src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o' -MF 'src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o.d' -o 'src/25a6634@@ndhcp4-private@sta/n-dhcp4-outgoing.c.o' -c ../src/n-dhcp4-outgoing.c
../src/n-dhcp4-outgoing.c: In function ‘n_dhcp4_outgoing_new’:
../src/n-dhcp4-outgoing.c:63:9: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
63 | static_assert(N_DHCP4_NETWORK_IP_MINIMUM_MAX_SIZE >= N_DHCP4_OUTGOING_MAX_PHDR +
| ^~~~~~~~~~~~~
Coverity says
CID 202453 (#1 of 1): Wrong sizeof argument (SIZEOF_MISMATCH)suspicious_sizeof:
Passing argument user_data of type gconstpointer and argument (gsize)nargs * 8UL /* sizeof (gconstpointer) */ to function g_slice_free1 is suspicious.
Let's pass instead the "data" pointer. It's the same, but maybe that
avoids the warning.
Coverity doesn't like us ignoring the return value, although
we really only care about the "p" output pointer.
Try casting the result to (void), maybe that silences Coverity.
- don't let no_auto_default_from_file() do any preprocessing of
the lines that it reads. It merely splits the lines at '\n'
and utf8safe-unescapes them.
This was previously duplicated also by NMConfigData's property
setter. We don't need to do it twice.
- sort the lines. This makes the entire handling O(n*ln(n)) instead
of O(n^2). Also, sorting effectively normalizes the content, and
it's desirable to have one true representation of what we write.
In particular when calling nm_utils_strv_sort() with a positive length
argument, then this is not a %NULL terminated strv arrary. That may mean
that it makes sense for the input array to contain %NULL strings.
Use a strcmp() function that accepts %NULL too.
While this is not used at the moment, I think nm_utils_strv_sort()
should accept %NULL strings beause otherwise it's a possibly unexpected
restriction of its API. The function should handle sensible input gracefully.
