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 "recurse-dir.h"
  13 #include "string-util.h"
  14 #include "strv.h"
  15 #include "virt.h"
  16
  17 #if HAVE_KMOD
  18 #include "module-util.h"
  19
  20 static void systemd_kmod_log(
  21                 void *data,
  22                 int priority,
  23                 const char *file, int line,
  24                 const char *fn,
  25                 const char *format,
  26                 va_list args) {
  27
  28         /* library logging is enabled at debug only */
  29         DISABLE_WARNING_FORMAT_NONLITERAL;
  30         log_internalv(LOG_DEBUG, 0, file, line, fn, format, args);
  31         REENABLE_WARNING;
  32 }
  33
  34 static int match_modalias_recurse_dir_cb(
  35                 RecurseDirEvent event,
  36                 const char *path,
  37                 int dir_fd,
  38                 int inode_fd,
  39                 const struct dirent *de,
  40                 const struct statx *sx,
  41                 void *userdata) {
  42
  43         _cleanup_free_ char *alias = NULL;
  44         char **modaliases = ASSERT_PTR(userdata);
  45         int r;
  46
  47         if (event != RECURSE_DIR_ENTRY)
  48                 return RECURSE_DIR_CONTINUE;
  49
  50         if (de->d_type != DT_REG)
  51                 return RECURSE_DIR_CONTINUE;
  52
  53         if (!streq(de->d_name, "modalias"))
  54                 return RECURSE_DIR_CONTINUE;
  55
  56         r = read_one_line_file(path, &alias);
  57         if (r < 0) {
  58                 log_debug_errno(r, "Failed to read %s, ignoring: %m", path);
  59                 return RECURSE_DIR_LEAVE_DIRECTORY;
  60         }
  61
  62         if (startswith_strv(alias, modaliases))
  63                 return 1;
  64
  65         return RECURSE_DIR_LEAVE_DIRECTORY;
  66 }
  67
  68 static bool has_virtio_feature(const char *name, char **modaliases) {
  69         int r;
  70
  71         /* Directory traversal might be slow, hence let's do a cheap check first if it's even worth it */
  72         if (detect_vm() == VIRTUALIZATION_NONE)
  73                 return false;
  74
  75         r = recurse_dir_at(
  76                         AT_FDCWD,
  77                         "/sys/devices/pci0000:00",
  78                         /* statx_mask= */ 0,
  79                         /* n_depth_max= */ 3,
  80                         RECURSE_DIR_ENSURE_TYPE,
  81                         match_modalias_recurse_dir_cb,
  82                         modaliases);
  83         if (r < 0)
  84                 log_debug_errno(r, "Failed to determine whether host has %s device, ignoring: %m", name);
  85
  86         return r > 0;
  87 }
  88
  89 static bool has_virtio_rng(void) {
  90         return has_virtio_feature("virtio-rng", STRV_MAKE("pci:v00001AF4d00001005", "pci:v00001AF4d00001044"));
  91 }
  92
  93 static bool has_virtio_console(void) {
  94         return has_virtio_feature("virtio-console", STRV_MAKE("virtio:d00000003v", "virtio:d0000000Bv"));
  95 }
  96
  97 static bool has_virtio_vsock(void) {
  98         return has_virtio_feature("virtio-vsock", STRV_MAKE("virtio:d00000013v"));
  99 }
 100
 101 static bool has_virtiofs(void) {
 102         return has_virtio_feature("virtiofs", STRV_MAKE("virtio:d0000001Av"));
 103 }
 104
 105 static bool has_virtio_pci(void) {
 106         return has_virtio_feature("virtio-pci", STRV_MAKE("pci:v00001AF4d"));
 107 }
 108
 109 static bool in_qemu(void) {
 110         return IN_SET(detect_vm(), VIRTUALIZATION_KVM, VIRTUALIZATION_QEMU);
 111 }
 112 #endif
 113
 114 int kmod_setup(void) {
 115 #if HAVE_KMOD
 116         static const struct {
 117                 const char *module;
 118                 const char *path;
 119                 bool warn_if_unavailable;
 120                 bool warn_if_module;
 121                 bool (*condition_fn)(void);
 122         } kmod_table[] = {
 123                 /* This one we need to load explicitly, since auto-loading on use doesn't work
 124                  * before udev created the ghost device nodes, and we need it earlier than that. */
 125                 { "autofs4",                    "/sys/class/misc/autofs",    true,  false, NULL               },
 126
 127                 /* This one we need to load explicitly, since auto-loading of IPv6 is not done when
 128                  * we try to configure ::1 on the loopback device. */
 129                 { "ipv6",                       "/sys/module/ipv6",          false, true,  NULL               },
 130
 131                 /* This should never be a module */
 132                 { "unix",                       "/proc/net/unix",            true,  true,  NULL               },
 133
 134 #if HAVE_LIBIPTC
 135                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
 136                 { "ip_tables",                  "/proc/net/ip_tables_names", false, false, NULL               },
 137 #endif
 138                 /* virtio_rng would be loaded by udev later, but real entropy might be needed very early */
 139                 { "virtio_rng",                 NULL,                        false, false, has_virtio_rng     },
 140
 141                 /* we want early logging to hvc consoles if possible, and make sure systemd-getty-generator
 142                  * can rely on all consoles being probed already.*/
 143                 { "virtio_console",             NULL,                        false, false, has_virtio_console },
 144
 145                 /* Make sure we can send sd-notify messages over vsock as early as possible. */
 146                 { "vmw_vsock_virtio_transport", NULL,                        false, false, has_virtio_vsock   },
 147
 148                 /* We can't wait for specific virtiofs tags to show up as device nodes so we have to load the
 149                  * virtiofs and virtio_pci modules early to make sure the virtiofs tags are found when
 150                  * sysroot.mount is started.
 151                  *
 152                  * TODO: Remove these again once https://gitlab.com/virtio-fs/virtiofsd/-/issues/128 is
 153                  * resolved and the kernel fix is widely available. */
 154                 { "virtiofs",                   "/sys/module/virtiofs",      false, false, has_virtiofs       },
 155                 { "virtio_pci",                 "/sys/module/virtio_pci",    false, false, has_virtio_pci     },
 156
 157                 /* qemu_fw_cfg would be loaded by udev later, but we want to import credentials from it super early */
 158                 { "qemu_fw_cfg",                "/sys/firmware/qemu_fw_cfg", false, false, in_qemu            },
 159
 160                 /* dmi-sysfs is needed to import credentials from it super early */
 161                 { "dmi-sysfs",                  "/sys/firmware/dmi/entries", false, false, NULL               },
 162
 163 #if HAVE_TPM2
 164                 /* Make sure the tpm subsystem is available which ConditionSecurity=tpm2 depends on. */
 165                 { "tpm",                        "/sys/class/tpmrm",          false, false, efi_has_tpm2       },
 166 #endif
 167         };
 168
 169         if (have_effective_cap(CAP_SYS_MODULE) <= 0)
 170                 return 0;
 171
 172         _cleanup_(kmod_unrefp) struct kmod_ctx *ctx = NULL;
 173
 174         FOREACH_ARRAY(kmod, kmod_table, ELEMENTSOF(kmod_table)) {
 175                 if (kmod->path && access(kmod->path, F_OK) >= 0)
 176                         continue;
 177
 178                 if (kmod->condition_fn && !kmod->condition_fn())
 179                         continue;
 180
 181                 if (kmod->warn_if_module)
 182                         log_debug("Your kernel apparently lacks built-in %s support. Might be "
 183                                   "a good idea to compile it in. We'll now try to work around "
 184                                   "this by loading the module...", kmod->module);
 185
 186                 if (!ctx) {
 187                         ctx = kmod_new(NULL, NULL);
 188                         if (!ctx)
 189                                 return log_oom();
 190
 191                         kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
 192                         kmod_load_resources(ctx);
 193                 }
 194
 195                 (void) module_load_and_warn(ctx, kmod->module, kmod->warn_if_unavailable);
 196         }
 197
 198 #endif
 199         return 0;
 200 }