src/core/kmod-setup.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <ftw.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6
   7 #include "alloc-util.h"
   8 #include "bus-util.h"
   9 #include "capability-util.h"
  10 #include "fileio.h"
  11 #include "kmod-setup.h"
  12 #include "macro.h"
  13 #include "string-util.h"
  14
  15 #if HAVE_KMOD
  16 #include <libkmod.h>
  17 #include "module-util.h"
  18
  19 static void systemd_kmod_log(
  20                 void *data,
  21                 int priority,
  22                 const char *file, int line,
  23                 const char *fn,
  24                 const char *format,
  25                 va_list args) {
  26
  27         /* library logging is enabled at debug only */
  28         DISABLE_WARNING_FORMAT_NONLITERAL;
  29         log_internalv(LOG_DEBUG, 0, file, line, fn, format, args);
  30         REENABLE_WARNING;
  31 }
  32
  33 static int has_virtio_rng_nftw_cb(
  34                 const char *fpath,
  35                 const struct stat *sb,
  36                 int tflag,
  37                 struct FTW *ftwbuf) {
  38
  39         _cleanup_free_ char *alias = NULL;
  40         int r;
  41
  42         if ((FTW_D == tflag) && (ftwbuf->level > 2))
  43                 return FTW_SKIP_SUBTREE;
  44
  45         if (FTW_F != tflag)
  46                 return FTW_CONTINUE;
  47
  48         if (!endswith(fpath, "/modalias"))
  49                 return FTW_CONTINUE;
  50
  51         r = read_one_line_file(fpath, &alias);
  52         if (r < 0)
  53                 return FTW_SKIP_SIBLINGS;
  54
  55         if (startswith(alias, "pci:v00001AF4d00001005"))
  56                 return FTW_STOP;
  57
  58         if (startswith(alias, "pci:v00001AF4d00001044"))
  59                 return FTW_STOP;
  60
  61         return FTW_SKIP_SIBLINGS;
  62 }
  63
  64 static bool has_virtio_rng(void) {
  65         return (nftw("/sys/devices/pci0000:00", has_virtio_rng_nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL) == FTW_STOP);
  66 }
  67 #endif
  68
  69 int kmod_setup(void) {
  70 #if HAVE_KMOD
  71
  72         static const struct {
  73                 const char *module;
  74                 const char *path;
  75                 bool warn_if_unavailable:1;
  76                 bool warn_if_module:1;
  77                 bool (*condition_fn)(void);
  78         } kmod_table[] = {
  79                 /* This one we need to load explicitly, since auto-loading on use doesn't work
  80                  * before udev created the ghost device nodes, and we need it earlier than that. */
  81                 { "autofs4",   "/sys/class/misc/autofs",    true,   false,   NULL      },
  82
  83                 /* This one we need to load explicitly, since auto-loading of IPv6 is not done when
  84                  * we try to configure ::1 on the loopback device. */
  85                 { "ipv6",      "/sys/module/ipv6",          false,  true,    NULL      },
  86
  87                 /* This should never be a module */
  88                 { "unix",      "/proc/net/unix",            true,   true,    NULL      },
  89
  90 #if HAVE_LIBIPTC
  91                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
  92                 { "ip_tables", "/proc/net/ip_tables_names", false,  false,   NULL      },
  93 #endif
  94                 /* virtio_rng would be loaded by udev later, but real entropy might be needed very early */
  95                 { "virtio_rng", NULL,                       false,  false,   has_virtio_rng },
  96         };
  97         _cleanup_(kmod_unrefp) struct kmod_ctx *ctx = NULL;
  98         unsigned int i;
  99
 100         if (have_effective_cap(CAP_SYS_MODULE) == 0)
 101                 return 0;
 102
 103         for (i = 0; i < ELEMENTSOF(kmod_table); i++) {
 104                 if (kmod_table[i].path && access(kmod_table[i].path, F_OK) >= 0)
 105                         continue;
 106
 107                 if (kmod_table[i].condition_fn && !kmod_table[i].condition_fn())
 108                         continue;
 109
 110                 if (kmod_table[i].warn_if_module)
 111                         log_debug("Your kernel apparently lacks built-in %s support. Might be "
 112                                   "a good idea to compile it in. We'll now try to work around "
 113                                   "this by loading the module...", kmod_table[i].module);
 114
 115                 if (!ctx) {
 116                         ctx = kmod_new(NULL, NULL);
 117                         if (!ctx)
 118                                 return log_oom();
 119
 120                         kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
 121                         kmod_load_resources(ctx);
 122                 }
 123
 124                 (void) module_load_and_warn(ctx, kmod_table[i].module, kmod_table[i].warn_if_unavailable);
 125         }
 126
 127 #endif
 128         return 0;
 129 }