lib/livepatch/test_klp_callbacks_demo2.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
   3
   4 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   5
   6 #include <linux/module.h>
   7 #include <linux/kernel.h>
   8 #include <linux/livepatch.h>
   9
  10 static int replace;
  11 module_param(replace, int, 0644);
  12 MODULE_PARM_DESC(replace, "replace (default=0)");
  13
  14 static const char *const module_state[] = {
  15         [MODULE_STATE_LIVE]     = "[MODULE_STATE_LIVE] Normal state",
  16         [MODULE_STATE_COMING]   = "[MODULE_STATE_COMING] Full formed, running module_init",
  17         [MODULE_STATE_GOING]    = "[MODULE_STATE_GOING] Going away",
  18         [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up",
  19 };
  20
  21 static void callback_info(const char *callback, struct klp_object *obj)
  22 {
  23         if (obj->mod)
  24                 pr_info("%s: %s -> %s\n", callback, obj->mod->name,
  25                         module_state[obj->mod->state]);
  26         else
  27                 pr_info("%s: vmlinux\n", callback);
  28 }
  29
  30 /* Executed on object patching (ie, patch enablement) */
  31 static int pre_patch_callback(struct klp_object *obj)
  32 {
  33         callback_info(__func__, obj);
  34         return 0;
  35 }
  36
  37 /* Executed on object unpatching (ie, patch disablement) */
  38 static void post_patch_callback(struct klp_object *obj)
  39 {
  40         callback_info(__func__, obj);
  41 }
  42
  43 /* Executed on object unpatching (ie, patch disablement) */
  44 static void pre_unpatch_callback(struct klp_object *obj)
  45 {
  46         callback_info(__func__, obj);
  47 }
  48
  49 /* Executed on object unpatching (ie, patch disablement) */
  50 static void post_unpatch_callback(struct klp_object *obj)
  51 {
  52         callback_info(__func__, obj);
  53 }
  54
  55 static struct klp_func no_funcs[] = {
  56         { }
  57 };
  58
  59 static struct klp_object objs[] = {
  60         {
  61                 .name = NULL,   /* vmlinux */
  62                 .funcs = no_funcs,
  63                 .callbacks = {
  64                         .pre_patch = pre_patch_callback,
  65                         .post_patch = post_patch_callback,
  66                         .pre_unpatch = pre_unpatch_callback,
  67                         .post_unpatch = post_unpatch_callback,
  68                 },
  69         }, { }
  70 };
  71
  72 static struct klp_patch patch = {
  73         .mod = THIS_MODULE,
  74         .objs = objs,
  75         /* set .replace in the init function below for demo purposes */
  76 };
  77
  78 static int test_klp_callbacks_demo2_init(void)
  79 {
  80         patch.replace = replace;
  81         return klp_enable_patch(&patch);
  82 }
  83
  84 static void test_klp_callbacks_demo2_exit(void)
  85 {
  86 }
  87
  88 module_init(test_klp_callbacks_demo2_init);
  89 module_exit(test_klp_callbacks_demo2_exit);
  90 MODULE_LICENSE("GPL");
  91 MODULE_INFO(livepatch, "Y");
  92 MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
  93 MODULE_DESCRIPTION("Livepatch test: livepatch demo2");