src/core/kmod-setup.c

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