src/core/kmod-setup.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <ftw.h>
   4 #include <unistd.h>
   5
   6 #include "alloc-util.h"
   7 #include "bus-util.h"
   8 #include "capability-util.h"
   9 #include "fileio.h"
  10 #include "kmod-setup.h"
  11 #include "macro.h"
  12 #include "string-util.h"
  13
  14 #if HAVE_KMOD
  15 #include <libkmod.h>
  16 #include "module-util.h"
  17
  18 static void systemd_kmod_log(
  19                 void *data,
  20                 int priority,
  21                 const char *file, int line,
  22                 const char *fn,
  23                 const char *format,
  24                 va_list args) {
  25
  26         /* library logging is enabled at debug only */
  27         DISABLE_WARNING_FORMAT_NONLITERAL;
  28         log_internalv(LOG_DEBUG, 0, file, line, fn, format, args);
  29         REENABLE_WARNING;
  30 }
  31
  32 static int has_virtio_rng_nftw_cb(
  33                 const char *fpath,
  34                 const struct stat *sb,
  35                 int tflag,
  36                 struct FTW *ftwbuf) {
  37
  38         _cleanup_free_ char *alias = NULL;
  39         int r;
  40
  41         if ((FTW_D == tflag) && (ftwbuf->level > 2))
  42                 return FTW_SKIP_SUBTREE;
  43
  44         if (FTW_F != tflag)
  45                 return FTW_CONTINUE;
  46
  47         if (!endswith(fpath, "/modalias"))
  48                 return FTW_CONTINUE;
  49
  50         r = read_one_line_file(fpath, &alias);
  51         if (r < 0)
  52                 return FTW_SKIP_SIBLINGS;
  53
  54         if (startswith(alias, "pci:v00001AF4d00001005"))
  55                 return FTW_STOP;
  56
  57         if (startswith(alias, "pci:v00001AF4d00001044"))
  58                 return FTW_STOP;
  59
  60         return FTW_SKIP_SIBLINGS;
  61 }
  62
  63 static bool has_virtio_rng(void) {
  64         return (nftw("/sys/devices/pci0000:00", has_virtio_rng_nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL) == FTW_STOP);
  65 }
  66 #endif
  67
  68 int kmod_setup(void) {
  69 #if HAVE_KMOD
  70
  71         static const struct {
  72                 const char *module;
  73                 const char *path;
  74                 bool warn_if_unavailable:1;
  75                 bool warn_if_module:1;
  76                 bool (*condition_fn)(void);
  77         } kmod_table[] = {
  78                 /* This one we need to load explicitly, since auto-loading on use doesn't work
  79                  * before udev created the ghost device nodes, and we need it earlier than that. */
  80                 { "autofs4",   "/sys/class/misc/autofs",    true,   false,   NULL      },
  81
  82                 /* This one we need to load explicitly, since auto-loading of IPv6 is not done when
  83                  * we try to configure ::1 on the loopback device. */
  84                 { "ipv6",      "/sys/module/ipv6",          false,  true,    NULL      },
  85
  86                 /* This should never be a module */
  87                 { "unix",      "/proc/net/unix",            true,   true,    NULL      },
  88
  89 #if HAVE_LIBIPTC
  90                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
  91                 { "ip_tables", "/proc/net/ip_tables_names", false,  false,   NULL      },
  92 #endif
  93                 /* virtio_rng would be loaded by udev later, but real entropy might be needed very early */
  94                 { "virtio_rng", NULL,                       false,  false,   has_virtio_rng },
  95         };
  96         _cleanup_(kmod_unrefp) struct kmod_ctx *ctx = NULL;
  97         unsigned i;
  98
  99         if (have_effective_cap(CAP_SYS_MODULE) == 0)
 100                 return 0;
 101
 102         for (i = 0; i < ELEMENTSOF(kmod_table); i++) {
 103                 if (kmod_table[i].path && access(kmod_table[i].path, F_OK) >= 0)
 104                         continue;
 105
 106                 if (kmod_table[i].condition_fn && !kmod_table[i].condition_fn())
 107                         continue;
 108
 109                 if (kmod_table[i].warn_if_module)
 110                         log_debug("Your kernel apparently lacks built-in %s support. Might be "
 111                                   "a good idea to compile it in. We'll now try to work around "
 112                                   "this by loading the module...", kmod_table[i].module);
 113
 114                 if (!ctx) {
 115                         ctx = kmod_new(NULL, NULL);
 116                         if (!ctx)
 117                                 return log_oom();
 118
 119                         kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
 120                         kmod_load_resources(ctx);
 121                 }
 122
 123                 (void) module_load_and_warn(ctx, kmod_table[i].module, kmod_table[i].warn_if_unavailable);
 124         }
 125
 126 #endif
 127         return 0;
 128 }