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 <sys/wait.h>
  23 #include <unistd.h>
  24 #include <string.h>
  25 #include <errno.h>
  26
  27 #ifdef HAVE_KMOD
  28 #include <libkmod.h>
  29 #endif
  30
  31 #include "macro.h"
  32 #include "execute.h"
  33 #include "capability.h"
  34 #include "kmod-setup.h"
  35
  36 #ifdef HAVE_KMOD
  37 static void systemd_kmod_log(
  38                 void *data,
  39                 int priority,
  40                 const char *file, int line,
  41                 const char *fn,
  42                 const char *format,
  43                 va_list args) {
  44
  45         /* library logging is enabled at debug only */
  46         DISABLE_WARNING_FORMAT_NONLITERAL;
  47         log_metav(LOG_DEBUG, file, line, fn, format, args);
  48         REENABLE_WARNING;
  49 }
  50
  51 static bool cmdline_check_kdbus(void) {
  52         _cleanup_free_ char *line = NULL;
  53         const char *p;
  54         int r;
  55
  56         r = proc_cmdline(&line);
  57         if (r < 0)
  58                 return false;
  59
  60         p = line;
  61         for (;;) {
  62                 _cleanup_free_ char *word = NULL;
  63
  64                 r = unquote_first_word(&p, &word, true);
  65                 if (r <= 0)
  66                         return false;
  67
  68                 if (streq(word, "kdbus"))
  69                         return true;
  70         }
  71 }
  72 #endif
  73
  74 int kmod_setup(void) {
  75 #ifdef HAVE_KMOD
  76
  77         static const struct {
  78                 const char *module;
  79                 const char *path;
  80                 bool warn;
  81                 bool (*condition_fn)(void);
  82         } kmod_table[] = {
  83                 /* auto-loading on use doesn't work before udev is up */
  84                 { "autofs4", "/sys/class/misc/autofs", true, NULL },
  85
  86                 /* early configure of ::1 on the loopback device */
  87                 { "ipv6",    "/sys/module/ipv6",       true, NULL },
  88
  89                 /* this should never be a module */
  90                 { "unix",    "/proc/net/unix",         true, NULL },
  91
  92                 /* IPC is needed before we bring up any other services */
  93                 { "kdbus",   "/sys/fs/kdbus",          false, cmdline_check_kdbus },
  94         };
  95         struct kmod_ctx *ctx = NULL;
  96         unsigned int i;
  97         int r;
  98
  99         if (have_effective_cap(CAP_SYS_MODULE) == 0)
 100                 return 0;
 101
 102         for (i = 0; i < ELEMENTSOF(kmod_table); i++) {
 103                 struct kmod_module *mod;
 104
 105                 if (kmod_table[i].path && access(kmod_table[i].path, F_OK) >= 0)
 106                         continue;
 107
 108                 if (kmod_table[i].condition_fn && !kmod_table[i].condition_fn())
 109                         continue;
 110
 111                 if (kmod_table[i].warn)
 112                         log_debug("Your kernel apparently lacks built-in %s support. Might be "
 113                                   "a good idea to compile it in. We'll now try to work around "
 114                                   "this by loading the module...", kmod_table[i].module);
 115
 116                 if (!ctx) {
 117                         ctx = kmod_new(NULL, NULL);
 118                         if (!ctx)
 119                                 return log_oom();
 120
 121                         kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
 122                         kmod_load_resources(ctx);
 123                 }
 124
 125                 r = kmod_module_new_from_name(ctx, kmod_table[i].module, &mod);
 126                 if (r < 0) {
 127                         log_error("Failed to lookup module '%s'", kmod_table[i].module);
 128                         continue;
 129                 }
 130
 131                 r = kmod_module_probe_insert_module(mod, KMOD_PROBE_APPLY_BLACKLIST, NULL, NULL, NULL, NULL);
 132                 if (r == 0)
 133                         log_info("Inserted module '%s'", kmod_module_get_name(mod));
 134                 else if (r == KMOD_PROBE_APPLY_BLACKLIST)
 135                         log_info("Module '%s' is blacklisted", kmod_module_get_name(mod));
 136                 else if (kmod_table[i].warn)
 137                         log_error("Failed to insert module '%s'", kmod_module_get_name(mod));
 138
 139                 kmod_module_unref(mod);
 140         }
 141
 142         if (ctx)
 143                 kmod_unref(ctx);
 144
 145 #endif
 146         return 0;
 147 }