WIP: kpatch-build: use symbol table instead of kobject

Signed-off-by: Artem Savkov <asavkov@redhat.com>
sm00th · May 11, 2018 · d61a44c · d61a44c
1 parent 9477a04
commit d61a44c
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Showing 3 changed files with 84 additions and 4 deletions.
diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build
@@ -780,8 +780,10 @@ for i in $FILES; do
 	fi
 	cd "$TEMPDIR" || die
 	if [[ -e "orig/$i" ]]; then
+		SYMTAB="$KOBJFILE.symtab"
+		readelf -W -s "$KOBJFILE" | tail -n +4 | awk '{ printf("%s %d %s %s %s %s\n", $2, $3, $4, $5, $7, $8 ? $8 : "__kpatch_noname__"); }' > "$SYMTAB"
 		# create-diff-object orig.o patched.o kernel-object output.o Module.symvers patch-mod-name
-		"$TOOLSDIR"/create-diff-object "orig/$i" "patched/$i" "$KOBJFILE" \
+		"$TOOLSDIR"/create-diff-object "orig/$i" "patched/$i" "$SYMTAB" \
 			"output/$i" "$SRCDIR/Module.symvers" "${MODNAME//-/_}" 2>&1 | logger 1
 		check_pipe_status create-diff-object
 		# create-diff-object returns 3 if no functional change is found

diff --git a/kpatch-build/lookup.c b/kpatch-build/lookup.c
@@ -174,6 +174,7 @@ static void find_local_syms(struct lookup_table *table, char *hint,
 		ERROR("find_local_syms for %s: found_none", hint);
 }
 
+#if 0
 static void obj_read(struct lookup_table *table, char *path)
 {
 	Elf *elf;
@@ -253,6 +254,7 @@ static void obj_read(struct lookup_table *table, char *path)
 	close(fd);
 	elf_end(elf);
 }
+#endif
 
 /* Strip the path and replace '-' with '_' */
 static char *make_modname(char *modname)
@@ -272,6 +274,77 @@ static char *make_modname(char *modname)
 	return basename(modname);
 }
 
+// TODO: rename?
+static void symtab_read(struct lookup_table *table, char *path)
+{
+	FILE *file;
+	unsigned int value, size, i = 0;
+	char name[256], type[256], vis[256], ndx[10];
+
+	if ((file = fopen(path, "r")) < 0)
+		ERROR("fopen");
+
+	while (fscanf(file, "%x %d %s %s %s %s\n",
+		      &value, &size, type, vis, ndx, name) != EOF) {
+		table->obj_nr++;
+	}
+
+	table->obj_syms = malloc(table->obj_nr * sizeof(*table->obj_syms));
+	if (!table->obj_syms)
+		ERROR("malloc table.obj_syms");
+	memset(table->obj_syms, 0, table->obj_nr * sizeof(*table->obj_syms));
+
+	rewind(file);
+
+	while (fscanf(file, "%x %d %s %s %s %s\n",
+		      &value, &size, type, vis, ndx, name) != EOF) {
+		if (!strcmp(ndx, "UND")) {
+			table->obj_syms[i].skip = 1;
+			i++;
+			continue;
+		}
+
+		table->obj_syms[i].value = value;
+		table->obj_syms[i].size = size;
+		table->obj_syms[i].name = strdup(name);
+
+		if (!strcmp(vis, "LOCAL")) {
+			table->obj_syms[i].bind = STB_LOCAL;
+		} else if (!strcmp(vis, "GLOBAL")) {
+			table->obj_syms[i].bind = STB_GLOBAL;
+		} else {
+			table->obj_syms[i].bind = STB_WEAK;
+		}
+
+		if (!strcmp(type, "NOTYPE")) {
+			table->obj_syms[i].type = STT_NOTYPE;
+		} else if (!strcmp(type, "OBJECT")) {
+			table->obj_syms[i].type = STT_OBJECT;
+		} else if (!strcmp(type, "FUNC")) {
+			table->obj_syms[i].type = STT_FUNC;
+		} else if (!strcmp(type, "SECTION")) {
+			table->obj_syms[i].type = STT_SECTION;
+		} else if (!strcmp(type, "FILE")) {
+			table->obj_syms[i].type = STT_FILE;
+		} else if (!strcmp(type, "COMMON")) {
+			table->obj_syms[i].type = STT_COMMON;
+		} else {
+			table->obj_syms[i].type = STT_TLS;
+		}
+
+		if (!strcmp(name, "__kpatch_noname__")) {
+			table->obj_syms[i].name = strdup("");
+		} else {
+			table->obj_syms[i].name = strdup(name);
+		}
+		if (!table->obj_syms[i].name)
+			ERROR("strdup");
+		i++;
+	}
+
+	fclose(file);
+}
+
 static void symvers_read(struct lookup_table *table, char *path)
 {
 	FILE *file;
@@ -324,7 +397,7 @@ struct lookup_table *lookup_open(char *obj_path, char *symvers_path,
 		ERROR("malloc table");
 	memset(table, 0, sizeof(*table));
 
-	obj_read(table, obj_path);
+	symtab_read(table, obj_path);
 	symvers_read(table, symvers_path);
 	find_local_syms(table, hint, locals);
 

diff --git a/test/unit/Makefile.include b/test/unit/Makefile.include
@@ -4,6 +4,7 @@ EXT_FAIL        ?= PATCHED.FAIL.o
 EXT_TEST        ?= test
 EXT_OUTPUT      ?= OUTPUT.o
 EXT_TEST_OUTPUT ?= test.out
+EXT_SYMTAB      ?= symtab
 TNAME            = $(@:.$(EXT_OUTPUT)=)
 
 ifndef VERBOSE
@@ -31,6 +32,10 @@ define check_all =
 	$(call check_stripped,$(1))
 endef
 
+define symtab_file =
+  $(if $(wildcard $(1).$(EXT_SYMTAB)),$(1).$(EXT_SYMTAB),vmlinux.$(EXT_SYMTAB))
+endef
+
 all: $(TARGETS) $(TEST_TARGETS)
 
 clean:
@@ -47,14 +52,14 @@ clean:
 	$(call check_all,$(TNAME).$(EXT_ORIG))
 	$(call check_all,$(TNAME).$(EXT_PATCHED))
 	$(CDO_ENV) $(CDO) $(TNAME).$(EXT_ORIG) $(TNAME).$(EXT_PATCHED) \
-		$(TNAME).$(EXT_ORIG) $@ /dev/null test_$(TNAME) $(MUTE_PASS)
+		$(call symtab_file,$(TNAME)) $@ /dev/null test_$(TNAME) $(MUTE_PASS)
 
 %.$(EXT_OUTPUT): %.$(EXT_ORIG) %.$(EXT_FAIL) $(CDO)
 	@echo "BUILD $(TNAME)-FAIL"
 	$(call check_all,$(TNAME).$(EXT_ORIG))
 	$(call check_all,$(TNAME).$(EXT_FAIL))
 	! $(CDO_ENV) $(CDO) $(TNAME).$(EXT_ORIG) $(TNAME).$(EXT_FAIL) \
-		$(TNAME).$(EXT_ORIG) $@ /dev/null test_$(TNAME) $(MUTE_FAIL)
+		$(call symtab_file,$(TNAME)) $@ /dev/null test_$(TNAME) $(MUTE_FAIL)
 # Expecting to fail, thus create output file manually so we won't rerun the
 # test without clean
 	@touch $@