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-rw-r--r--src/core/kmod-setup.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/src/core/kmod-setup.c b/src/core/kmod-setup.c
new file mode 100644
index 0000000..a91cfeb
--- /dev/null
+++ b/src/core/kmod-setup.c
@@ -0,0 +1,129 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <ftw.h>
+#include <string.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 <libkmod.h>
+#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;
+}