src/core/kmod-setup.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <unistd.h>
   4
   5 #include "alloc-util.h"
   6 #include "bus-util.h"
   7 #include "capability-util.h"
   8 #include "efi-api.h"
   9 #include "fileio.h"
  10 #include "kmod-setup.h"
  11 #include "macro.h"
  12 #include "module-util.h"
  13 #include "recurse-dir.h"
  14 #include "string-util.h"
  15 #include "strv.h"
  16 #include "virt.h"
  17
  18 #if HAVE_KMOD
  19 static int match_modalias_recurse_dir_cb(
  20                 RecurseDirEvent event,
  21                 const char *path,
  22                 int dir_fd,
  23                 int inode_fd,
  24                 const struct dirent *de,
  25                 const struct statx *sx,
  26                 void *userdata) {
  27
  28         _cleanup_free_ char *alias = NULL;
  29         char **modaliases = ASSERT_PTR(userdata);
  30         int r;
  31
  32         if (event != RECURSE_DIR_ENTRY)
  33                 return RECURSE_DIR_CONTINUE;
  34
  35         if (de->d_type != DT_REG)
  36                 return RECURSE_DIR_CONTINUE;
  37
  38         if (!streq(de->d_name, "modalias"))
  39                 return RECURSE_DIR_CONTINUE;
  40
  41         r = read_one_line_file(path, &alias);
  42         if (r < 0) {
  43                 log_debug_errno(r, "Failed to read %s, ignoring: %m", path);
  44                 return RECURSE_DIR_LEAVE_DIRECTORY;
  45         }
  46
  47         if (startswith_strv(alias, modaliases))
  48                 return 1;
  49
  50         return RECURSE_DIR_LEAVE_DIRECTORY;
  51 }
  52
  53 static bool has_virtio_feature(const char *name, char **modaliases) {
  54         int r;
  55
  56         /* Directory traversal might be slow, hence let's do a cheap check first if it's even worth it */
  57         if (detect_vm() == VIRTUALIZATION_NONE)
  58                 return false;
  59
  60         r = recurse_dir_at(
  61                         AT_FDCWD,
  62                         "/sys/devices/pci0000:00",
  63                         /* statx_mask= */ 0,
  64                         /* n_depth_max= */ 3,
  65                         RECURSE_DIR_ENSURE_TYPE,
  66                         match_modalias_recurse_dir_cb,
  67                         modaliases);
  68         if (r < 0)
  69                 log_debug_errno(r, "Failed to determine whether host has %s device, ignoring: %m", name);
  70
  71         return r > 0;
  72 }
  73
  74 static bool has_virtio_rng(void) {
  75         return has_virtio_feature("virtio-rng", STRV_MAKE("pci:v00001AF4d00001005", "pci:v00001AF4d00001044"));
  76 }
  77
  78 static bool has_virtio_console(void) {
  79         return has_virtio_feature("virtio-console", STRV_MAKE("virtio:d00000003v", "virtio:d0000000Bv"));
  80 }
  81
  82 static bool has_virtio_vsock(void) {
  83         return has_virtio_feature("virtio-vsock", STRV_MAKE("virtio:d00000013v"));
  84 }
  85
  86 static bool has_virtiofs(void) {
  87         return has_virtio_feature("virtiofs", STRV_MAKE("virtio:d0000001Av"));
  88 }
  89
  90 static bool has_virtio_pci(void) {
  91         return has_virtio_feature("virtio-pci", STRV_MAKE("pci:v00001AF4d"));
  92 }
  93
  94 static bool in_qemu(void) {
  95         return IN_SET(detect_vm(), VIRTUALIZATION_KVM, VIRTUALIZATION_QEMU);
  96 }
  97 #endif
  98
  99 int kmod_setup(void) {
 100 #if HAVE_KMOD
 101         static const struct {
 102                 const char *module;
 103                 const char *path;
 104                 bool warn_if_unavailable;
 105                 bool warn_if_module;
 106                 bool (*condition_fn)(void);
 107         } kmod_table[] = {
 108                 /* This one we need to load explicitly, since auto-loading on use doesn't work
 109                  * before udev created the ghost device nodes, and we need it earlier than that. */
 110                 { "autofs4",                    "/sys/class/misc/autofs",    true,  false, NULL               },
 111
 112                 /* This one we need to load explicitly, since auto-loading of IPv6 is not done when
 113                  * we try to configure ::1 on the loopback device. */
 114                 { "ipv6",                       "/sys/module/ipv6",          false, true,  NULL               },
 115
 116                 /* This should never be a module */
 117                 { "unix",                       "/proc/net/unix",            true,  true,  NULL               },
 118
 119 #if HAVE_LIBIPTC
 120                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
 121                 { "ip_tables",                  "/proc/net/ip_tables_names", false, false, NULL               },
 122 #endif
 123                 /* virtio_rng would be loaded by udev later, but real entropy might be needed very early */
 124                 { "virtio_rng",                 NULL,                        false, false, has_virtio_rng     },
 125
 126                 /* we want early logging to hvc consoles if possible, and make sure systemd-getty-generator
 127                  * can rely on all consoles being probed already.*/
 128                 { "virtio_console",             NULL,                        false, false, has_virtio_console },
 129
 130                 /* Make sure we can send sd-notify messages over vsock as early as possible. */
 131                 { "vmw_vsock_virtio_transport", NULL,                        false, false, has_virtio_vsock   },
 132
 133                 /* We can't wait for specific virtiofs tags to show up as device nodes so we have to load the
 134                  * virtiofs and virtio_pci modules early to make sure the virtiofs tags are found when
 135                  * sysroot.mount is started.
 136                  *
 137                  * TODO: Remove these again once https://gitlab.com/virtio-fs/virtiofsd/-/issues/128 is
 138                  * resolved and the kernel fix is widely available. */
 139                 { "virtiofs",                   "/sys/module/virtiofs",      false, false, has_virtiofs       },
 140                 { "virtio_pci",                 "/sys/module/virtio_pci",    false, false, has_virtio_pci     },
 141
 142                 /* qemu_fw_cfg would be loaded by udev later, but we want to import credentials from it super early */
 143                 { "qemu_fw_cfg",                "/sys/firmware/qemu_fw_cfg", false, false, in_qemu            },
 144
 145                 /* dmi-sysfs is needed to import credentials from it super early */
 146                 { "dmi-sysfs",                  "/sys/firmware/dmi/entries", false, false, NULL               },
 147
 148 #if HAVE_TPM2
 149                 /* Make sure the tpm subsystem is available which ConditionSecurity=tpm2 depends on. */
 150                 { "tpm",                        "/sys/class/tpmrm",          false, false, efi_has_tpm2       },
 151 #endif
 152         };
 153
 154         int r;
 155
 156         if (have_effective_cap(CAP_SYS_MODULE) <= 0)
 157                 return 0;
 158
 159         _cleanup_(sym_kmod_unrefp) struct kmod_ctx *ctx = NULL;
 160         FOREACH_ELEMENT(kmod, kmod_table) {
 161                 if (kmod->path && access(kmod->path, F_OK) >= 0)
 162                         continue;
 163
 164                 if (kmod->condition_fn && !kmod->condition_fn())
 165                         continue;
 166
 167                 if (kmod->warn_if_module)
 168                         log_debug("Your kernel apparently lacks built-in %s support. Might be "
 169                                   "a good idea to compile it in. We'll now try to work around "
 170                                   "this by loading the module...", kmod->module);
 171
 172                 if (!ctx) {
 173                         r = module_setup_context(&ctx);
 174                         if (r < 0)
 175                                 return log_error_errno(r, "Failed to initialize kmod context: %m");
 176                 }
 177
 178                 (void) module_load_and_warn(ctx, kmod->module, kmod->warn_if_unavailable);
 179         }
 180
 181 #endif
 182         return 0;
 183 }