src/core/kmod-setup.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <string.h>
  23 #include <unistd.h>
  24
  25 #ifdef HAVE_KMOD
  26 #include <libkmod.h>
  27 #endif
  28
  29 #include "bus-util.h"
  30 #include "capability-util.h"
  31 #include "kmod-setup.h"
  32 #include "macro.h"
  33
  34 #ifdef HAVE_KMOD
  35 static void systemd_kmod_log(
  36                 void *data,
  37                 int priority,
  38                 const char *file, int line,
  39                 const char *fn,
  40                 const char *format,
  41                 va_list args) {
  42
  43         /* library logging is enabled at debug only */
  44         DISABLE_WARNING_FORMAT_NONLITERAL;
  45         log_internalv(LOG_DEBUG, 0, file, line, fn, format, args);
  46         REENABLE_WARNING;
  47 }
  48 #endif
  49
  50 int kmod_setup(void) {
  51 #ifdef HAVE_KMOD
  52
  53         static const struct {
  54                 const char *module;
  55                 const char *path;
  56                 bool warn_if_unavailable:1;
  57                 bool warn_if_module:1;
  58                 bool (*condition_fn)(void);
  59         } kmod_table[] = {
  60                 /* auto-loading on use doesn't work before udev is up */
  61                 { "autofs4",   "/sys/class/misc/autofs",    true,   false,   NULL      },
  62
  63                 /* early configure of ::1 on the loopback device */
  64                 { "ipv6",      "/sys/module/ipv6",          false,  true,    NULL      },
  65
  66                 /* this should never be a module */
  67                 { "unix",      "/proc/net/unix",            true,   true,    NULL      },
  68
  69                 /* IPC is needed before we bring up any other services */
  70                 { "kdbus",     "/sys/fs/kdbus",             false,  false,   is_kdbus_wanted },
  71
  72 #ifdef HAVE_LIBIPTC
  73                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
  74                 { "ip_tables", "/proc/net/ip_tables_names", false,  false,   NULL      },
  75 #endif
  76         };
  77         struct kmod_ctx *ctx = NULL;
  78         unsigned int i;
  79         int r;
  80
  81         if (have_effective_cap(CAP_SYS_MODULE) == 0)
  82                 return 0;
  83
  84         for (i = 0; i < ELEMENTSOF(kmod_table); i++) {
  85                 struct kmod_module *mod;
  86
  87                 if (kmod_table[i].path && access(kmod_table[i].path, F_OK) >= 0)
  88                         continue;
  89
  90                 if (kmod_table[i].condition_fn && !kmod_table[i].condition_fn())
  91                         continue;
  92
  93                 if (kmod_table[i].warn_if_module)
  94                         log_debug("Your kernel apparently lacks built-in %s support. Might be "
  95                                   "a good idea to compile it in. We'll now try to work around "
  96                                   "this by loading the module...", kmod_table[i].module);
  97
  98                 if (!ctx) {
  99                         ctx = kmod_new(NULL, NULL);
 100                         if (!ctx)
 101                                 return log_oom();
 102
 103                         kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
 104                         kmod_load_resources(ctx);
 105                 }
 106
 107                 r = kmod_module_new_from_name(ctx, kmod_table[i].module, &mod);
 108                 if (r < 0) {
 109                         log_error("Failed to lookup module '%s'", kmod_table[i].module);
 110                         continue;
 111                 }
 112
 113                 r = kmod_module_probe_insert_module(mod, KMOD_PROBE_APPLY_BLACKLIST, NULL, NULL, NULL, NULL);
 114                 if (r == 0)
 115                         log_debug("Inserted module '%s'", kmod_module_get_name(mod));
 116                 else if (r == KMOD_PROBE_APPLY_BLACKLIST)
 117                         log_info("Module '%s' is blacklisted", kmod_module_get_name(mod));
 118                 else {
 119                         bool print_warning = kmod_table[i].warn_if_unavailable || (r < 0 && r != -ENOENT);
 120
 121                         log_full_errno(print_warning ? LOG_WARNING : LOG_DEBUG, r,
 122                                        "Failed to insert module '%s': %m", kmod_module_get_name(mod));
 123                 }
 124
 125                 kmod_module_unref(mod);
 126         }
 127
 128         if (ctx)
 129                 kmod_unref(ctx);
 130
 131 #endif
 132         return 0;
 133 }