From 6851b62e08b75fc9bd40ea04fbabc9afb3e9f2c2 Mon Sep 17 00:00:00 2001 From: Pawel Wieczorkiewicz Date: Tue, 26 Nov 2019 12:25:06 +0000 Subject: [PATCH] create-diff-object: Handle extra pre-|post- hooks Include new sections containing optional pre-, post- action hooks. The following new section names are supported: - .livepatch.hooks.preapply - .livepatch.hooks.postapply - .livepatch.hooks.prerevert - .livepatch.hooks.postrevert Signed-off-by: Pawel Wieczorkiewicz Reviewed-by: Ross Lagerwall Signed-off-by: Ross Lagerwall --- create-diff-object.c | 67 +++++++++++++++++++++++++++++++++++--------- 1 file changed, 54 insertions(+), 13 deletions(-) diff --git a/create-diff-object.c b/create-diff-object.c index bdbd27a..b53cd5c 100644 --- a/create-diff-object.c +++ b/create-diff-object.c @@ -1115,6 +1115,22 @@ static struct special_section special_sections[] = { .name = ".livepatch.hooks.unload", .group_size = livepatch_hooks_group_size, }, + { + .name = ".livepatch.hooks.preapply", + .group_size = livepatch_hooks_group_size, + }, + { + .name = ".livepatch.hooks.postapply", + .group_size = livepatch_hooks_group_size, + }, + { + .name = ".livepatch.hooks.prerevert", + .group_size = livepatch_hooks_group_size, + }, + { + .name = ".livepatch.hooks.postrevert", + .group_size = livepatch_hooks_group_size, + }, {}, }; @@ -1478,23 +1494,44 @@ static void kpatch_include_debug_sections(struct kpatch_elf *kelf) } } -static void kpatch_include_hook_elements(struct kpatch_elf *kelf) +#define IS_HOOK_SECTION(section, hook) ({ \ + !strcmp(((section))->name, ".livepatch.hooks." hook) || \ + !strcmp(((section))->name, ".rela.livepatch.hooks." hook); \ +}) + +#define IS_ACTION_HOOK_SECTION(section, action) ({ \ + IS_HOOK_SECTION(section, "pre" action) || \ + IS_HOOK_SECTION(section, "post" action); \ +}) + +#define IS_HOOK_SYM_NAME(symbol, hook) ({ \ + !strcmp(((symbol))->name, "livepatch_" hook "_data"); \ +}) + +#define IS_ACTION_HOOK_SYM_NAME(symbol, action) ({ \ + IS_HOOK_SYM_NAME(symbol, "pre" action) || \ + IS_HOOK_SYM_NAME(symbol, "post" action); \ +}) + +static int kpatch_include_hook_elements(struct kpatch_elf *kelf) { struct section *sec; struct symbol *sym; struct rela *rela; + int num_new_functions = 0; - /* include load/unload sections */ + /* include all supported hooks sections */ list_for_each_entry(sec, &kelf->sections, list) { - if (!strcmp(sec->name, ".livepatch.hooks.load") || - !strcmp(sec->name, ".livepatch.hooks.unload") || - !strcmp(sec->name, ".rela.livepatch.hooks.load") || - !strcmp(sec->name, ".rela.livepatch.hooks.unload")) { + if (IS_HOOK_SECTION(sec, "load") || + IS_HOOK_SECTION(sec, "unload") || + IS_ACTION_HOOK_SECTION(sec, "apply") || + IS_ACTION_HOOK_SECTION(sec, "revert")) { sec->include = 1; + num_new_functions++; if (is_rela_section(sec)) { /* include hook dependencies */ rela = list_entry(sec->relas.next, - struct rela, list); + struct rela, list); sym = rela->sym; log_normal("found hook: %s\n",sym->name); kpatch_include_symbol(sym, 0); @@ -1510,13 +1547,17 @@ static void kpatch_include_hook_elements(struct kpatch_elf *kelf) } /* - * Strip temporary global load/unload function pointer objects - * used by the kpatch_[load|unload]() macros. + * Strip temporary global function pointer objects for all + * supported hooks, used by the kpatch_[load|unload]() macros. */ list_for_each_entry(sym, &kelf->symbols, list) - if (!strcmp(sym->name, "livepatch_load_data") || - !strcmp(sym->name, "livepatch_unload_data")) + if (IS_HOOK_SYM_NAME(sym, "load") || + IS_HOOK_SYM_NAME(sym, "unload") || + IS_ACTION_HOOK_SYM_NAME(sym, "apply") || + IS_ACTION_HOOK_SYM_NAME(sym, "revert")) sym->include = 0; + + return num_new_functions; } static int kpatch_include_new_globals(struct kpatch_elf *kelf) @@ -2313,11 +2354,11 @@ int main(int argc, char *argv[]) kpatch_include_standard_elements(kelf_patched); log_debug("Include changed functions\n"); num_changed = kpatch_include_changed_functions(kelf_patched); - log_debug("num_changed = %d\n", num_changed); log_debug("Include debug sections\n"); kpatch_include_debug_sections(kelf_patched); log_debug("Include hook elements\n"); - kpatch_include_hook_elements(kelf_patched); + num_changed += kpatch_include_hook_elements(kelf_patched); + log_debug("num_changed = %d\n", num_changed); log_debug("Include new globals\n"); new_globals_exist = kpatch_include_new_globals(kelf_patched); log_debug("new_globals_exist = %d\n", new_globals_exist); -- 2.39.5