src/core/kmod-setup.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <string.h>
  21 #include <unistd.h>
  22
  23 #ifdef HAVE_KMOD
  24 #include <libkmod.h>
  25 #endif
  26
  27 #include "bus-util.h"
  28 #include "capability-util.h"
  29 #include "kmod-setup.h"
  30 #include "macro.h"
  31
  32 #ifdef HAVE_KMOD
  33 static void systemd_kmod_log(
  34                 void *data,
  35                 int priority,
  36                 const char *file, int line,
  37                 const char *fn,
  38                 const char *format,
  39                 va_list args) {
  40
  41         /* library logging is enabled at debug only */
  42         DISABLE_WARNING_FORMAT_NONLITERAL;
  43         log_internalv(LOG_DEBUG, 0, file, line, fn, format, args);
  44         REENABLE_WARNING;
  45 }
  46 #endif
  47
  48 int kmod_setup(void) {
  49 #ifdef HAVE_KMOD
  50
  51         static const struct {
  52                 const char *module;
  53                 const char *path;
  54                 bool warn_if_unavailable:1;
  55                 bool warn_if_module:1;
  56                 bool (*condition_fn)(void);
  57         } kmod_table[] = {
  58                 /* auto-loading on use doesn't work before udev is up */
  59                 { "autofs4",   "/sys/class/misc/autofs",    true,   false,   NULL      },
  60
  61                 /* early configure of ::1 on the loopback device */
  62                 { "ipv6",      "/sys/module/ipv6",          false,  true,    NULL      },
  63
  64                 /* this should never be a module */
  65                 { "unix",      "/proc/net/unix",            true,   true,    NULL      },
  66
  67                 /* IPC is needed before we bring up any other services */
  68                 { "kdbus",     "/sys/fs/kdbus",             false,  false,   is_kdbus_wanted },
  69
  70 #ifdef HAVE_LIBIPTC
  71                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
  72                 { "ip_tables", "/proc/net/ip_tables_names", false,  false,   NULL      },
  73 #endif
  74         };
  75         struct kmod_ctx *ctx = NULL;
  76         unsigned int i;
  77         int r;
  78
  79         if (have_effective_cap(CAP_SYS_MODULE) == 0)
  80                 return 0;
  81
  82         for (i = 0; i < ELEMENTSOF(kmod_table); i++) {
  83                 struct kmod_module *mod;
  84
  85                 if (kmod_table[i].path && access(kmod_table[i].path, F_OK) >= 0)
  86                         continue;
  87
  88                 if (kmod_table[i].condition_fn && !kmod_table[i].condition_fn())
  89                         continue;
  90
  91                 if (kmod_table[i].warn_if_module)
  92                         log_debug("Your kernel apparently lacks built-in %s support. Might be "
  93                                   "a good idea to compile it in. We'll now try to work around "
  94                                   "this by loading the module...", kmod_table[i].module);
  95
  96                 if (!ctx) {
  97                         ctx = kmod_new(NULL, NULL);
  98                         if (!ctx)
  99                                 return log_oom();
 100
 101                         kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
 102                         kmod_load_resources(ctx);
 103                 }
 104
 105                 r = kmod_module_new_from_name(ctx, kmod_table[i].module, &mod);
 106                 if (r < 0) {
 107                         log_error("Failed to lookup module '%s'", kmod_table[i].module);
 108                         continue;
 109                 }
 110
 111                 r = kmod_module_probe_insert_module(mod, KMOD_PROBE_APPLY_BLACKLIST, NULL, NULL, NULL, NULL);
 112                 if (r == 0)
 113                         log_debug("Inserted module '%s'", kmod_module_get_name(mod));
 114                 else if (r == KMOD_PROBE_APPLY_BLACKLIST)
 115                         log_info("Module '%s' is blacklisted", kmod_module_get_name(mod));
 116                 else {
 117                         bool print_warning = kmod_table[i].warn_if_unavailable || (r < 0 && r != -ENOENT);
 118
 119                         log_full_errno(print_warning ? LOG_WARNING : LOG_DEBUG, r,
 120                                        "Failed to insert module '%s': %m", kmod_module_get_name(mod));
 121                 }
 122
 123                 kmod_module_unref(mod);
 124         }
 125
 126         if (ctx)
 127                 kmod_unref(ctx);
 128
 129 #endif
 130         return 0;
 131 }