src/udev/udev-builtin-kmod.c

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * load kernel modules
   4  *
   5  * Copyright © 2011 ProFUSION embedded systems
   6  */
   7
   8 #include "device-util.h"
   9 #include "module-util.h"
  10 #include "string-util.h"
  11 #include "strv.h"
  12 #include "udev-builtin.h"
  13
  14 static struct kmod_ctx *ctx = NULL;
  15
  16 static int builtin_kmod(UdevEvent *event, int argc, char *argv[]) {
  17         sd_device *dev = ASSERT_PTR(ASSERT_PTR(event)->dev);
  18         int r;
  19
  20         if (event->event_mode != EVENT_UDEV_WORKER) {
  21                 log_device_debug(dev, "Running in test mode, skipping execution of 'kmod' builtin command.");
  22                 return 0;
  23         }
  24
  25         if (!ctx)
  26                 return 0;
  27
  28         if (argc < 2 || !streq(argv[1], "load"))
  29                 return log_device_warning_errno(dev, SYNTHETIC_ERRNO(EINVAL),
  30                                                 "%s: expected: load [module…]", argv[0]);
  31
  32         char **modules = strv_skip(argv, 2);
  33         if (modules)
  34                 STRV_FOREACH(module, modules)
  35                         (void) module_load_and_warn(ctx, *module, /* verbose = */ false);
  36         else {
  37                 const char *modalias;
  38
  39                 r = sd_device_get_property_value(dev, "MODALIAS", &modalias);
  40                 if (r < 0)
  41                         return log_device_warning_errno(dev, r, "Failed to read property \"MODALIAS\": %m");
  42
  43                 (void) module_load_and_warn(ctx, modalias, /* verbose = */ false);
  44         }
  45
  46         return 0;
  47 }
  48
  49 /* called at udev startup and reload */
  50 static int builtin_kmod_init(void) {
  51         int r;
  52
  53         if (ctx)
  54                 return 0;
  55
  56         r = module_setup_context(&ctx);
  57         if (r < 0)
  58                 return log_error_errno(r, "Failed to initialize libkmod context: %m");
  59
  60         log_debug("Loaded kernel module index.");
  61         return 0;
  62 }
  63
  64 /* called on udev shutdown and reload request */
  65 static void builtin_kmod_exit(void) {
  66         if (!ctx)
  67                 return;
  68
  69         ctx = sym_kmod_unref(ctx);
  70         log_debug("Unloaded kernel module index.");
  71 }
  72
  73 /* called every couple of seconds during event activity; 'true' if config has changed */
  74 static bool builtin_kmod_should_reload(void) {
  75         if (!ctx)
  76                 return false;
  77
  78         if (sym_kmod_validate_resources(ctx) != KMOD_RESOURCES_OK) {
  79                 log_debug("Kernel module index needs reloading.");
  80                 return true;
  81         }
  82
  83         return false;
  84 }
  85
  86 const UdevBuiltin udev_builtin_kmod = {
  87         .name = "kmod",
  88         .cmd = builtin_kmod,
  89         .init = builtin_kmod_init,
  90         .exit = builtin_kmod_exit,
  91         .should_reload = builtin_kmod_should_reload,
  92         .help = "Kernel module loader",
  93         .run_once = false,
  94 };