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 <unistd.h>
  23 #include <string.h>
  24
  25 #ifdef HAVE_KMOD
  26 #include <libkmod.h>
  27 #endif
  28
  29 #include "macro.h"
  30 #include "capability.h"
  31 #include "bus-util.h"
  32 #include "kmod-setup.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 #ifdef ENABLE_KDBUS
  70                 /* IPC is needed before we bring up any other services */
  71                 { "kdbus",     "/sys/fs/kdbus",             false,  false,   is_kdbus_wanted },
  72 #endif
  73
  74 #ifdef HAVE_LIBIPTC
  75                 /* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
  76                 { "ip_tables", "/proc/net/ip_tables_names", false,  false,   NULL      },
  77 #endif
  78         };
  79         struct kmod_ctx *ctx = NULL;
  80         unsigned int i;
  81         int r;
  82
  83         if (have_effective_cap(CAP_SYS_MODULE) == 0)
  84                 return 0;
  85
  86         for (i = 0; i < ELEMENTSOF(kmod_table); i++) {
  87                 struct kmod_module *mod;
  88
  89                 if (kmod_table[i].path && access(kmod_table[i].path, F_OK) >= 0)
  90                         continue;
  91
  92                 if (kmod_table[i].condition_fn && !kmod_table[i].condition_fn())
  93                         continue;
  94
  95                 if (kmod_table[i].warn_if_module)
  96                         log_debug("Your kernel apparently lacks built-in %s support. Might be "
  97                                   "a good idea to compile it in. We'll now try to work around "
  98                                   "this by loading the module...", kmod_table[i].module);
  99
 100                 if (!ctx) {
 101                         ctx = kmod_new(NULL, NULL);
 102                         if (!ctx)
 103                                 return log_oom();
 104
 105                         kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
 106                         kmod_load_resources(ctx);
 107                 }
 108
 109                 r = kmod_module_new_from_name(ctx, kmod_table[i].module, &mod);
 110                 if (r < 0) {
 111                         log_error("Failed to lookup module '%s'", kmod_table[i].module);
 112                         continue;
 113                 }
 114
 115                 r = kmod_module_probe_insert_module(mod, KMOD_PROBE_APPLY_BLACKLIST, NULL, NULL, NULL, NULL);
 116                 if (r == 0)
 117                         log_info("Inserted module '%s'", kmod_module_get_name(mod));
 118                 else if (r == KMOD_PROBE_APPLY_BLACKLIST)
 119                         log_info("Module '%s' is blacklisted", kmod_module_get_name(mod));
 120                 else {
 121                         bool print_warning = kmod_table[i].warn_if_unavailable || (r < 0 && r != -ENOSYS);
 122
 123                         log_full_errno(print_warning ? LOG_WARNING : LOG_DEBUG, r,
 124                                        "Failed to insert module '%s': %m", kmod_module_get_name(mod));
 125                 }
 126
 127                 kmod_module_unref(mod);
 128         }
 129
 130         if (ctx)
 131                 kmod_unref(ctx);
 132
 133 #endif
 134         return 0;
 135 }