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