libkmod: turn into dlopen() dependency

As it turns out libkmod has quite a bunch of deps, including various
compressing libs and similar. By turning this into a dlopen()
dependency, we can make our depchain during install time quite a bit
smaller. In particular as inside of containers kmod doesn't help anyway
as CAP_SYS_MODULE is not available anyway.

While we are at it, also share the code that sets up logging/kmod
context.

After:

$ lddtree ./build/systemd
systemd => ./build/systemd (interpreter => /lib64/ld-linux-x86-64.so.2)
    libsystemd-core-255.so => ./build/src/core/libsystemd-core-255.so
        libaudit.so.1 => /lib64/libaudit.so.1
            libcap-ng.so.0 => /lib64/libcap-ng.so.0
                ld-linux-x86-64.so.2 => /lib64/ld-linux-x86-64.so.2
        libm.so.6 => /lib64/libm.so.6
        libmount.so.1 => /lib64/libmount.so.1
            libblkid.so.1 => /lib64/libblkid.so.1
        libseccomp.so.2 => /lib64/libseccomp.so.2
        libselinux.so.1 => /lib64/libselinux.so.1
            libpcre2-8.so.0 => /lib64/libpcre2-8.so.0
    libsystemd-shared-255.so => /home/lennart/projects/systemd/build/src/shared/libsystemd-shared-255.so
        libacl.so.1 => /lib64/libacl.so.1
            libattr.so.1 => /lib64/libattr.so.1
        libcap.so.2 => /lib64/libcap.so.2
        libcrypt.so.2 => /lib64/libcrypt.so.2
        libgcrypt.so.20 => /lib64/libgcrypt.so.20
            libgpg-error.so.0 => /lib64/libgpg-error.so.0
        liblz4.so.1 => /lib64/liblz4.so.1
        libcrypto.so.3 => /lib64/libcrypto.so.3
            libz.so.1 => /lib64/libz.so.1
        libpam.so.0 => /lib64/libpam.so.0
            libeconf.so.0 => /lib64/libeconf.so.0
        liblzma.so.5 => /lib64/liblzma.so.5
        libzstd.so.1 => /lib64/libzstd.so.1
    libc.so.6 => /lib64/libc.so.6

Before:

$ lddtree ./build/systemd
systemd => ./build/systemd (interpreter => /lib64/ld-linux-x86-64.so.2)
    libsystemd-core-255.so => ./build/src/core/libsystemd-core-255.so
        libaudit.so.1 => /lib64/libaudit.so.1
            libcap-ng.so.0 => /lib64/libcap-ng.so.0
                ld-linux-x86-64.so.2 => /lib64/ld-linux-x86-64.so.2
        libkmod.so.2 => /lib64/libkmod.so.2
            libzstd.so.1 => /lib64/libzstd.so.1
            liblzma.so.5 => /lib64/liblzma.so.5
            libz.so.1 => /lib64/libz.so.1
            libcrypto.so.3 => /lib64/libcrypto.so.3
            libgcc_s.so.1 => /lib64/libgcc_s.so.1
        libm.so.6 => /lib64/libm.so.6
        libmount.so.1 => /lib64/libmount.so.1
            libblkid.so.1 => /lib64/libblkid.so.1
        libseccomp.so.2 => /lib64/libseccomp.so.2
        libselinux.so.1 => /lib64/libselinux.so.1
            libpcre2-8.so.0 => /lib64/libpcre2-8.so.0
    libsystemd-shared-255.so => /home/lennart/projects/systemd/build/src/shared/libsystemd-shared-255.so
        libacl.so.1 => /lib64/libacl.so.1
            libattr.so.1 => /lib64/libattr.so.1
        libcap.so.2 => /lib64/libcap.so.2
        libcrypt.so.2 => /lib64/libcrypt.so.2
        libgcrypt.so.20 => /lib64/libgcrypt.so.20
            libgpg-error.so.0 => /lib64/libgpg-error.so.0
        liblz4.so.1 => /lib64/liblz4.so.1
        libpam.so.0 => /lib64/libpam.so.0
            libeconf.so.0 => /lib64/libeconf.so.0
    libc.so.6 => /lib64/libc.so.6

2 files changed, 15 insertions, 14 deletions

diff --git a/src/udev/meson.build b/src/udev/meson.build
index e5b52ab642..3535551e74 100644
--- a/src/udev/meson.build
+++ b/src/udev/meson.build
@@ -114,7 +114,7 @@ libudevd_core = static_library(
         include_directories : includes + include_directories('net'),
         link_with : udev_link_with,
         dependencies : [libblkid,
-                        libkmod,
+                        libkmod_cflags,
                         userspace],
         build_by_default : false)
 
diff --git a/src/udev/udev-builtin-kmod.c b/src/udev/udev-builtin-kmod.c
index 6d37af88a3..f4aa4802c9 100644
--- a/src/udev/udev-builtin-kmod.c
+++ b/src/udev/udev-builtin-kmod.c
@@ -18,10 +18,6 @@
 
 static struct kmod_ctx *ctx = NULL;
 
-_printf_(6,0) static void udev_kmod_log(void *data, int priority, const char *file, int line, const char *fn, const char *format, va_list args) {
-        log_internalv(priority, 0, file, line, fn, format, args);
-}
-
 static int builtin_kmod(UdevEvent *event, int argc, char *argv[]) {
         sd_device *dev = ASSERT_PTR(ASSERT_PTR(event)->dev);
         int r;
@@ -44,7 +40,7 @@ static int builtin_kmod(UdevEvent *event, int argc, char *argv[]) {
 
                 r = sd_device_get_property_value(dev, "MODALIAS", &modalias);
                 if (r < 0)
-                        return log_device_warning_errno(dev, r, "Failed to read property \"MODALIAS\".");
+                        return log_device_warning_errno(dev, r, "Failed to read property \"MODALIAS\": %m");
 
                 (void) module_load_and_warn(ctx, modalias, /* verbose = */ false);
         } else
@@ -56,23 +52,28 @@ static int builtin_kmod(UdevEvent *event, int argc, char *argv[]) {
 
 /* called at udev startup and reload */
 static int builtin_kmod_init(void) {
+        int r;
+
         if (ctx)
                 return 0;
 
-        ctx = kmod_new(NULL, NULL);
-        if (!ctx)
-                return -ENOMEM;
-
         log_debug("Loading kernel module index.");
-        kmod_set_log_fn(ctx, udev_kmod_log, NULL);
-        kmod_load_resources(ctx);
+
+        r = module_setup_context(&ctx);
+        if (r < 0)
+                return log_error_errno(r, "Failed to initialize libkmod context: %m");
+
         return 0;
 }
 
 /* called on udev shutdown and reload request */
 static void builtin_kmod_exit(void) {
         log_debug("Unload kernel module index.");
-        ctx = kmod_unref(ctx);
+
+        if (!ctx)
+                return;
+
+        ctx = sym_kmod_unref(ctx);
 }
 
 /* called every couple of seconds during event activity; 'true' if config has changed */
@@ -80,7 +81,7 @@ static bool builtin_kmod_should_reload(void) {
         if (!ctx)
                 return false;
 
-        if (kmod_validate_resources(ctx) != KMOD_RESOURCES_OK) {
+        if (sym_kmod_validate_resources(ctx) != KMOD_RESOURCES_OK) {
                 log_debug("Kernel module index needs reloading.");
                 return true;
         }