[tor-commits] [tor/master] Add new "struct_var_" functions to manipulate struct fields.
dgoulet at torproject.org
dgoulet at torproject.org
Thu Aug 22 21:12:54 UTC 2019
commit 2da188667d37757ae999c8ab24ed35b64e08700c
Author: Nick Mathewson <nickm at torproject.org>
Date: Tue Jun 18 20:40:11 2019 -0400
Add new "struct_var_" functions to manipulate struct fields.
These functions exist one level higher than typed_var_t. They
describe a type, a name, and an offset within a structure.
---
src/lib/conf/conftypes.h | 40 +++++++++
src/lib/confmgt/include.am | 2 +
src/lib/confmgt/structvar.c | 200 ++++++++++++++++++++++++++++++++++++++++++++
src/lib/confmgt/structvar.h | 51 +++++++++++
4 files changed, 293 insertions(+)
diff --git a/src/lib/conf/conftypes.h b/src/lib/conf/conftypes.h
index e66ab3d5a..cddfeff2f 100644
--- a/src/lib/conf/conftypes.h
+++ b/src/lib/conf/conftypes.h
@@ -63,8 +63,48 @@ typedef enum config_type_t {
CONFIG_TYPE_ROUTERSET, /**< A list of router names, addrs, and fps,
* parsed into a routerset_t. */
CONFIG_TYPE_OBSOLETE, /**< Obsolete (ignored) option. */
+ CONFIG_TYPE_EXTENDED, /**< Extended type; definition will appear in
+ * pointer. */
} config_type_t;
+/* Forward delcaration for var_type_def_t, for extended types. */
+struct var_type_def_t;
+
+/** Structure to specify a named, typed member within a structure. */
+typedef struct struct_member_t {
+ /** Name of the field. */
+ const char *name;
+ /** Type of the field, according to the config_type_t enumeration.
+ *
+ * This value is CONFIG_TYPE_EXTENDED for any type not listed in
+ * config_type_t.
+ **/
+ config_type_t type;
+ /**
+ * Pointer to a type definition for the type of this field. Overrides
+ * <b>type</b> if not NULL.
+ **/
+ const struct var_type_def_t *type_def;
+ /**
+ * Offset of this field within the structure. Compute this with
+ * offsetof(structure, fieldname).
+ **/
+ int offset;
+} struct_member_t;
+
+/**
+ * Structure to describe the location and preferred value of a "magic number"
+ * field within a structure.
+ *
+ * These 'magic numbers' are 32-bit values used to tag objects to make sure
+ * that they have the correct type.
+ */
+typedef struct struct_magic_decl_t {
+ const char *typename;
+ uint32_t magic_val;
+ int magic_offset;
+} struct_magic_decl_t;
+
#ifdef TOR_UNIT_TESTS
/**
* Union used when building in test mode typechecking the members of a type
diff --git a/src/lib/confmgt/include.am b/src/lib/confmgt/include.am
index a2c764995..aa5b37fdb 100644
--- a/src/lib/confmgt/include.am
+++ b/src/lib/confmgt/include.am
@@ -6,6 +6,7 @@ endif
# ADD_C_FILE: INSERT SOURCES HERE.
src_lib_libtor_confmgt_a_SOURCES = \
+ src/lib/confmgt/structvar.c \
src/lib/confmgt/type_defs.c \
src/lib/confmgt/typedvar.c \
src/lib/confmgt/unitparse.c
@@ -17,6 +18,7 @@ src_lib_libtor_confmgt_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
# ADD_C_FILE: INSERT HEADERS HERE.
noinst_HEADERS += \
+ src/lib/confmgt/structvar.h \
src/lib/confmgt/type_defs.h \
src/lib/confmgt/typedvar.h \
src/lib/confmgt/unitparse.h \
diff --git a/src/lib/confmgt/structvar.c b/src/lib/confmgt/structvar.c
new file mode 100644
index 000000000..7ea00fbde
--- /dev/null
+++ b/src/lib/confmgt/structvar.c
@@ -0,0 +1,200 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file structvar.c
+ * @brief Functions to manipulate named and typed elements of
+ * a structure.
+ *
+ * These functions represent a low-level API for accessing a member of a
+ * structure. They use typedvar.c to work, and they are used in turn by the
+ * configuration system to examine and set fields in configuration objects
+ * used by individual modules.
+ *
+ * Almost no code should call these directly.
+ **/
+
+#include "orconfig.h"
+#include "lib/confmgt/structvar.h"
+#include "lib/cc/compat_compiler.h"
+#include "lib/conf/conftypes.h"
+#include "lib/confmgt/type_defs.h"
+#include "lib/confmgt/typedvar.h"
+#include "lib/log/util_bug.h"
+
+#include <stddef.h>
+
+/**
+ * Set the 'magic number' on <b>object</b> to correspond to decl.
+ **/
+void
+struct_set_magic(void *object, const struct_magic_decl_t *decl)
+{
+ tor_assert(object);
+ tor_assert(decl);
+ uint32_t *ptr = STRUCT_VAR_P(object, decl->magic_offset);
+ *ptr = decl->magic_val;
+}
+
+/**
+ * Assert that the 'magic number' on <b>object</b> to corresponds to decl.
+ **/
+void
+struct_check_magic(const void *object, const struct_magic_decl_t *decl)
+{
+ tor_assert(object);
+ tor_assert(decl);
+
+ const uint32_t *ptr = STRUCT_VAR_P(object, decl->magic_offset);
+ tor_assertf(*ptr == decl->magic_val,
+ "Bad magic number on purported %s object. "
+ "Expected %"PRIu32"x but got "PRIu32"x.",
+ decl->magic_val, *ptr);
+}
+
+/**
+ * Return a mutable pointer to the member of <b>object</b> described
+ * by <b>member</b>.
+ **/
+void *
+struct_get_mptr(void *object, const struct_member_t *member)
+{
+ tor_assert(object);
+ return STRUCT_VAR_P(object, member->offset);
+}
+
+/**
+ * Return a const pointer to the member of <b>object</b> described
+ * by <b>member</b>.
+ **/
+const void *
+struct_get_ptr(const void *object, const struct_member_t *member)
+{
+ tor_assert(object);
+ return STRUCT_VAR_P(object, member->offset);
+}
+
+/**
+ * Helper: given a struct_member_t, look up the type definition for its
+ * variable.
+ */
+static const var_type_def_t *
+get_type_def(const struct_member_t *member)
+{
+ if (member->type_def)
+ return member->type_def;
+
+ return lookup_type_def(member->type);
+}
+
+/**
+ * (As typed_var_assign, but assign a value to the member of <b>object</b>
+ * defined by <b>member</b>.)
+ **/
+int
+struct_var_assign(void *object, const char *value, char **errmsg,
+ const struct_member_t *member)
+{
+ void *p = struct_get_mptr(object, member);
+ const var_type_def_t *def = get_type_def(member);
+
+ return typed_var_assign_ex(p, value, errmsg, def);
+}
+
+/**
+ * (As typed_var_free, but free and clear the member of <b>object</b> defined
+ * by <b>member</b>.)
+ **/
+void
+struct_var_free(void *object, const struct_member_t *member)
+{
+ void *p = struct_get_mptr(object, member);
+ const var_type_def_t *def = get_type_def(member);
+
+ typed_var_free_ex(p, def);
+}
+
+/**
+ * (As typed_var_encode, but encode the member of <b>object</b> defined
+ * by <b>member</b>.)
+ **/
+char *
+struct_var_encode(const void *object, const struct_member_t *member)
+{
+ const void *p = struct_get_ptr(object, member);
+ const var_type_def_t *def = get_type_def(member);
+
+ return typed_var_encode_ex(p, def);
+}
+
+/**
+ * (As typed_var_copy, but copy from <b>src</b> to <b>dest</b> the member
+ * defined by <b>member</b>.)
+ **/
+int
+struct_var_copy(void *dest, const void *src, const struct_member_t *member)
+{
+ void *p_dest = struct_get_mptr(dest, member);
+ const void *p_src = struct_get_ptr(src, member);
+ const var_type_def_t *def = get_type_def(member);
+
+ return typed_var_copy_ex(p_dest, p_src, def);
+}
+
+/**
+ * (As typed_var_eq, but compare the members of <b>a</b> and <b>b</b>
+ * defined by <b>member</b>.)
+ **/
+bool
+struct_var_eq(const void *a, const void *b, const struct_member_t *member)
+{
+ const void *p_a = struct_get_ptr(a, member);
+ const void *p_b = struct_get_ptr(b, member);
+ const var_type_def_t *def = get_type_def(member);
+
+ return typed_var_eq_ex(p_a, p_b, def);
+}
+
+/**
+ * (As typed_var_ok, but validate the member of <b>object</b> defined by
+ * <b>member</b>.)
+ **/
+bool
+struct_var_ok(const void *object, const struct_member_t *member)
+{
+ const void *p = struct_get_ptr(object, member);
+ const var_type_def_t *def = get_type_def(member);
+
+ return typed_var_ok_ex(p, def);
+}
+
+/**
+ * (As typed_var_kvassign, but assign a value to the member of <b>object</b>
+ * defined by <b>member</b>.)
+ **/
+int
+struct_var_kvassign(void *object, const struct config_line_t *line,
+ char **errmsg,
+ const struct_member_t *member)
+{
+ void *p = struct_get_mptr(object, member);
+ const var_type_def_t *def = get_type_def(member);
+
+ return typed_var_kvassign_ex(p, line, errmsg, def);
+}
+
+/**
+ * (As typed_var_kvencode, but encode the value of the member of <b>object</b>
+ * defined by <b>member</b>.)
+ **/
+struct config_line_t *
+struct_var_kvencode(const void *object, const struct_member_t *member)
+{
+ const void *p = struct_get_ptr(object, member);
+ const var_type_def_t *def = get_type_def(member);
+
+ return typed_var_kvencode_ex(member->name, p, def);
+}
diff --git a/src/lib/confmgt/structvar.h b/src/lib/confmgt/structvar.h
new file mode 100644
index 000000000..894098e50
--- /dev/null
+++ b/src/lib/confmgt/structvar.h
@@ -0,0 +1,51 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file structvar.h
+ * @brief Header for lib/confmgt/structvar.c
+ **/
+
+#ifndef TOR_LIB_CONFMGT_STRUCTVAR_H
+#define TOR_LIB_CONFMGT_STRUCTVAR_H
+
+struct struct_magic_decl_t;
+struct struct_member_t;
+struct config_line_t;
+
+#include <stdbool.h>
+
+void struct_set_magic(void *object,
+ const struct struct_magic_decl_t *decl);
+void struct_check_magic(const void *object,
+ const struct struct_magic_decl_t *decl);
+
+void *struct_get_mptr(void *object,
+ const struct struct_member_t *member);
+const void *struct_get_ptr(const void *object,
+ const struct struct_member_t *member);
+
+int struct_var_assign(void *object, const char *value, char **errmsg,
+ const struct struct_member_t *member);
+void struct_var_free(void *object,
+ const struct struct_member_t *member);
+char *struct_var_encode(const void *object,
+ const struct struct_member_t *member);
+int struct_var_copy(void *dest, const void *src,
+ const struct struct_member_t *member);
+bool struct_var_eq(const void *a, const void *b,
+ const struct struct_member_t *member);
+bool struct_var_ok(const void *object,
+ const struct struct_member_t *member);
+
+int struct_var_kvassign(void *object, const struct config_line_t *line,
+ char **errmsg,
+ const struct struct_member_t *member);
+struct config_line_t *struct_var_kvencode(
+ const void *object,
+ const struct struct_member_t *member);
+
+#endif /* !defined(TOR_LIB_CONFMGT_STRUCTVAR_H) */
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