src/core/kmod-setup.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6 ***/
   7
   8 #include <ftw.h>
   9 #include <string.h>
  10 #include <unistd.h>
  11
  12 #include "alloc-util.h"
  13 #include "bus-util.h"
  14 #include "capability-util.h"
  15 #include "fileio.h"
  16 #include "kmod-setup.h"
  17 #include "macro.h"
  18 #include "string-util.h"
  19
  20 #if HAVE_KMOD
  21 #include <libkmod.h>
  22 #include "module-util.h"
  23
  24 static void systemd_kmod_log(
  25                 void *data,
  26                 int priority,
  27                 const char *file, int line,
  28                 const char *fn,
  29                 const char *format,
  30                 va_list args) {
  31
  32         /* library logging is enabled at debug only */
  33         DISABLE_WARNING_FORMAT_NONLITERAL;
  34         log_internalv(LOG_DEBUG, 0, file, line, fn, format, args);
  35         REENABLE_WARNING;
  36 }
  37
  38 static int has_virtio_rng_nftw_cb(
  39                 const char *fpath,
  40                 const struct stat *sb,
  41                 int tflag,
  42                 struct FTW *ftwbuf) {
  43
  44         _cleanup_free_ char *alias = NULL;
  45         int r;
  46
  47         if ((FTW_D == tflag) && (ftwbuf->level > 2))
  48                 return FTW_SKIP_SUBTREE;
  49
  50         if (FTW_F != tflag)
  51                 return FTW_CONTINUE;
  52
  53         if (!endswith(fpath, "/modalias"))
  54                 return FTW_CONTINUE;
  55
  56         r = read_one_line_file(fpath, &alias);
  57         if (r < 0)
  58                 return FTW_SKIP_SIBLINGS;
  59
  60         if (startswith(alias, "pci:v00001AF4d00001005"))
  61                 return FTW_STOP;
  62
  63         if (startswith(alias, "pci:v00001AF4d00001044"))
  64                 return FTW_STOP;
  65
  66         return FTW_SKIP_SIBLINGS;
  67 }
  68
  69 static bool has_virtio_rng(void) {
  70         return (nftw("/sys/devices/pci0000:00", has_virtio_rng_nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL) == FTW_STOP);
  71 }
  72 #endif
  73
  74 int kmod_setup(void) {
  75 #if HAVE_KMOD
  76
  77         static const struct {
  78                 const char *module;
  79                 const char *path;
  80                 bool warn_if_unavailable:1;
  81                 bool warn_if_module:1;
  82                 bool (*condition_fn)(void);
  83         } kmod_table[] = {
  84                 /* auto-loading on use doesn't work before udev is up */
  85                 { "autofs4",   "/sys/class/misc/autofs",    true,   false,   NULL      },
  86
  87                 /* early configure of ::1 on the loopback device */
  88                 { "ipv6",      "/sys/module/ipv6",          false,  true,    NULL      },
  89
  90                 /* this should never be a module */
  91                 { "unix",      "/proc/net/unix",            true,   true,    NULL      },
  92
  93 #if HAVE_LIBIPTC
  94                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
  95                 { "ip_tables", "/proc/net/ip_tables_names", false,  false,   NULL      },
  96 #endif
  97                 /* virtio_rng would be loaded by udev later, but real entropy might be needed very early */
  98                 { "virtio_rng", NULL,                       false,  false,   has_virtio_rng },
  99         };
 100         _cleanup_(kmod_unrefp) struct kmod_ctx *ctx = NULL;
 101         unsigned int i;
 102         int r;
 103
 104         if (have_effective_cap(CAP_SYS_MODULE) == 0)
 105                 return 0;
 106
 107         for (i = 0; i < ELEMENTSOF(kmod_table); i++) {
 108                 _cleanup_(kmod_module_unrefp) struct kmod_module *mod = NULL;
 109
 110                 if (kmod_table[i].path && access(kmod_table[i].path, F_OK) >= 0)
 111                         continue;
 112
 113                 if (kmod_table[i].condition_fn && !kmod_table[i].condition_fn())
 114                         continue;
 115
 116                 if (kmod_table[i].warn_if_module)
 117                         log_debug("Your kernel apparently lacks built-in %s support. Might be "
 118                                   "a good idea to compile it in. We'll now try to work around "
 119                                   "this by loading the module...", kmod_table[i].module);
 120
 121                 if (!ctx) {
 122                         ctx = kmod_new(NULL, NULL);
 123                         if (!ctx)
 124                                 return log_oom();
 125
 126                         kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
 127                         kmod_load_resources(ctx);
 128                 }
 129
 130                 r = kmod_module_new_from_name(ctx, kmod_table[i].module, &mod);
 131                 if (r < 0) {
 132                         log_error("Failed to lookup module '%s'", kmod_table[i].module);
 133                         continue;
 134                 }
 135
 136                 r = kmod_module_probe_insert_module(mod, KMOD_PROBE_APPLY_BLACKLIST, NULL, NULL, NULL, NULL);
 137                 if (r == 0)
 138                         log_debug("Inserted module '%s'", kmod_module_get_name(mod));
 139                 else if (r == KMOD_PROBE_APPLY_BLACKLIST)
 140                         log_info("Module '%s' is blacklisted", kmod_module_get_name(mod));
 141                 else {
 142                         bool print_warning = kmod_table[i].warn_if_unavailable || (r < 0 && r != -ENOENT);
 143
 144                         log_full_errno(print_warning ? LOG_WARNING : LOG_DEBUG, r,
 145                                        "Failed to insert module '%s': %m", kmod_module_get_name(mod));
 146                 }
 147         }
 148
 149 #endif
 150         return 0;
 151 }