| Quellcodebibliothek Statistik Leitseite products/sources/formale Sprachen/C/Linux/samples/livepatch/ (Open Source Betriebssystem Version 6.17.9©) Datei vom 24.10.2025 mit Größe 5 kB |
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Quelle livepatch-callbacks-demo.c Sprache: C |
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// SPDX-License-Identifier: GPL-2.0-or-later
/* * Copyright (C) 2017 Joe Lawrence <joe.lawrence@redhat.com> */ /* * livepatch-callbacks-demo.c - (un)patching callbacks livepatch demo * * * Purpose * ------- * * Demonstration of registering livepatch (un)patching callbacks. * * * Usage * ----- * * Step 1 - load the simple module * * insmod samples/livepatch/livepatch-callbacks-mod.ko * * * Step 2 - load the demonstration livepatch (with callbacks) * * insmod samples/livepatch/livepatch-callbacks-demo.ko * * * Step 3 - cleanup * * echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled * rmmod livepatch_callbacks_demo * rmmod livepatch_callbacks_mod * * Watch dmesg output to see livepatch enablement, callback execution * and patching operations for both vmlinux and module targets. * * NOTE: swap the insmod order of livepatch-callbacks-mod.ko and * livepatch-callbacks-demo.ko to observe what happens when a * target module is loaded after a livepatch with callbacks. * * NOTE: 'pre_patch_ret' is a module parameter that sets the pre-patch * callback return status. Try setting up a non-zero status * such as -19 (-ENODEV): * * # Load demo livepatch, vmlinux is patched * insmod samples/livepatch/livepatch-callbacks-demo.ko * * # Setup next pre-patch callback to return -ENODEV * echo -19 > /sys/module/livepatch_callbacks_demo/parameters/pre_patch_ret * * # Module loader refuses to load the target module * insmod samples/livepatch/livepatch-callbacks-mod.ko * insmod: ERROR: could not insert module samples/livepatch/livepatch-callbacks-mod.ko: N * * NOTE: There is a second target module, * livepatch-callbacks-busymod.ko, available for experimenting * with livepatch (un)patch callbacks. This module contains * a 'sleep_secs' parameter that parks the module on one of the * functions that the livepatch demo module wants to patch. * Modifying this value and tweaking the order of module loads can * effectively demonstrate stalled patch transitions: * * # Load a target module, let it park on 'busymod_work_func' for * # thirty seconds * insmod samples/livepatch/livepatch-callbacks-busymod.ko sleep_secs=30 * * # Meanwhile load the livepatch * insmod samples/livepatch/livepatch-callbacks-demo.ko * * # ... then load and unload another target module while the * # transition is in progress * insmod samples/livepatch/livepatch-callbacks-mod.ko * rmmod samples/livepatch/livepatch-callbacks-mod.ko * * # Finally cleanup * echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled * rmmod samples/livepatch/livepatch-callbacks-demo.ko */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/kernel.h> #include <linux/livepatch.h> static int pre_patch_ret; module_param(pre_patch_ret, int, 0644); MODULE_PARM_DESC(pre_patch_ret, "pre_patch_ret (default=0)"); static const char *const module_state[] = { [MODULE_STATE_LIVE] = "[MODULE_STATE_LIVE] Normal state", [MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init", [MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away", [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up", }; static void callback_info(const char *callback, struct klp_object *obj) { if (obj->mod) pr_info("%s: %s -> %s\n", callback, obj->mod->name, module_state[obj->mod->state]); else pr_info("%s: vmlinux\n", callback); } /* Executed on object patching (ie, patch enablement) */ static int pre_patch_callback(struct klp_object *obj) { callback_info(__func__, obj); return pre_patch_ret; } /* Executed on object unpatching (ie, patch disablement) */ static void post_patch_callback(struct klp_object *obj) { callback_info(__func__, obj); } /* Executed on object unpatching (ie, patch disablement) */ static void pre_unpatch_callback(struct klp_object *obj) { callback_info(__func__, obj); } /* Executed on object unpatching (ie, patch disablement) */ static void post_unpatch_callback(struct klp_object *obj) { callback_info(__func__, obj); } static void patched_work_func(struct work_struct *work) { pr_info("%s\n", __func__); } static struct klp_func no_funcs[] = { { } }; static struct klp_func busymod_funcs[] = { { .old_name = "busymod_work_func", .new_func = patched_work_func, }, { } }; static struct klp_object objs[] = { { .name = NULL, /* vmlinux */ .funcs = no_funcs, .callbacks = { .pre_patch = pre_patch_callback, .post_patch = post_patch_callback, .pre_unpatch = pre_unpatch_callback, .post_unpatch = post_unpatch_callback, }, }, { .name = "livepatch_callbacks_mod", .funcs = no_funcs, .callbacks = { .pre_patch = pre_patch_callback, .post_patch = post_patch_callback, .pre_unpatch = pre_unpatch_callback, .post_unpatch = post_unpatch_callback, }, }, { .name = "livepatch_callbacks_busymod", .funcs = busymod_funcs, .callbacks = { .pre_patch = pre_patch_callback, .post_patch = post_patch_callback, .pre_unpatch = pre_unpatch_callback, .post_unpatch = post_unpatch_callback, }, }, { } }; static struct klp_patch patch = { .mod = THIS_MODULE, .objs = objs, }; static int livepatch_callbacks_demo_init(void) { return klp_enable_patch(&patch); } static void livepatch_callbacks_demo_exit(void) { } module_init(livepatch_callbacks_demo_init); module_exit(livepatch_callbacks_demo_exit); MODULE_DESCRIPTION("Live patching demo for (un)patching callbacks"); MODULE_LICENSE("GPL"); MODULE_INFO(livepatch, "Y"); ¤ Dauer der Verarbeitung: 0.25 Sekunden (vorverarbeitet) ¤*© Formatika GbR, Deutschland |
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2026-03-28