1 files changed, 127 insertions, 0 deletions
diff --git a/src/core/kmod-setup.c b/src/core/kmod-setup.c
new file mode 100644
index 0000000..8a7f828
--- /dev/null
+++ b/src/core/kmod-setup.c
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <ftw.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "bus-util.h"
+#include "capability-util.h"
+#include "fileio.h"
+#include "kmod-setup.h"
+#include "macro.h"
+#include "string-util.h"
+
+#if HAVE_KMOD
+#include "module-util.h"
+
+static void systemd_kmod_log(
+                void *data,
+                int priority,
+                const char *file, int line,
+                const char *fn,
+                const char *format,
+                va_list args) {
+
+        /* library logging is enabled at debug only */
+        DISABLE_WARNING_FORMAT_NONLITERAL;
+        log_internalv(LOG_DEBUG, 0, file, line, fn, format, args);
+        REENABLE_WARNING;
+}
+
+static int has_virtio_rng_nftw_cb(
+                const char *fpath,
+                const struct stat *sb,
+                int tflag,
+                struct FTW *ftwbuf) {
+
+        _cleanup_free_ char *alias = NULL;
+        int r;
+
+        if ((FTW_D == tflag) && (ftwbuf->level > 2))
+                return FTW_SKIP_SUBTREE;
+
+        if (FTW_F != tflag)
+                return FTW_CONTINUE;
+
+        if (!endswith(fpath, "/modalias"))
+                return FTW_CONTINUE;
+
+        r = read_one_line_file(fpath, &alias);
+        if (r < 0)
+                return FTW_SKIP_SIBLINGS;
+
+        if (startswith(alias, "pci:v00001AF4d00001005"))
+                return FTW_STOP;
+
+        if (startswith(alias, "pci:v00001AF4d00001044"))
+                return FTW_STOP;
+
+        return FTW_SKIP_SIBLINGS;
+}
+
+static bool has_virtio_rng(void) {
+        return (nftw("/sys/devices/pci0000:00", has_virtio_rng_nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL) == FTW_STOP);
+}
+#endif
+
+int kmod_setup(void) {
+#if HAVE_KMOD
+
+        static const struct {
+                const char *module;
+                const char *path;
+                bool warn_if_unavailable:1;
+                bool warn_if_module:1;
+                bool (*condition_fn)(void);
+        } kmod_table[] = {
+                /* This one we need to load explicitly, since auto-loading on use doesn't work
+                 * before udev created the ghost device nodes, and we need it earlier than that. */
+                { "autofs4",   "/sys/class/misc/autofs",    true,   false,   NULL      },
+
+                /* This one we need to load explicitly, since auto-loading of IPv6 is not done when
+                 * we try to configure ::1 on the loopback device. */
+                { "ipv6",      "/sys/module/ipv6",          false,  true,    NULL      },
+
+                /* This should never be a module */
+                { "unix",      "/proc/net/unix",            true,   true,    NULL      },
+
+#if HAVE_LIBIPTC
+                /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
+                { "ip_tables", "/proc/net/ip_tables_names", false,  false,   NULL      },
+#endif
+                /* virtio_rng would be loaded by udev later, but real entropy might be needed very early */
+                { "virtio_rng", NULL,                       false,  false,   has_virtio_rng },
+        };
+        _cleanup_(kmod_unrefp) struct kmod_ctx *ctx = NULL;
+        unsigned i;
+
+        if (have_effective_cap(CAP_SYS_MODULE) == 0)
+                return 0;
+
+        for (i = 0; i < ELEMENTSOF(kmod_table); i++) {
+                if (kmod_table[i].path && access(kmod_table[i].path, F_OK) >= 0)
+                        continue;
+
+                if (kmod_table[i].condition_fn && !kmod_table[i].condition_fn())
+                        continue;
+
+                if (kmod_table[i].warn_if_module)
+                        log_debug("Your kernel apparently lacks built-in %s support. Might be "
+                                  "a good idea to compile it in. We'll now try to work around "
+                                  "this by loading the module...", kmod_table[i].module);
+
+                if (!ctx) {
+                        ctx = kmod_new(NULL, NULL);
+                        if (!ctx)
+                                return log_oom();
+
+                        kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
+                        kmod_load_resources(ctx);
+                }
+
+                (void) module_load_and_warn(ctx, kmod_table[i].module, kmod_table[i].warn_if_unavailable);
+        }
+
+#endif
+        return 0;
+}