[tor-commits] [tor/master] Start on a command-parsing tool for controller commands.
dgoulet at torproject.org
dgoulet at torproject.org
Tue Apr 30 15:57:51 UTC 2019
commit de70eebc65d40d50f877b0f82df4d05ce670faa5
Author: Nick Mathewson <nickm at torproject.org>
Date: Tue Apr 2 08:17:22 2019 -0400
Start on a command-parsing tool for controller commands.
There _is_ an underlying logic to these commands, but it isn't
wholly uniform, given years of tweaks and changes. Fortunately I
think there is a superset that will work.
This commit adds a parser for some of the most basic cases -- the
ones currently handled by getargs_helper() and some of the
object-taking ones. Soon will come initial tests; then I'll start using
the parser.
After that, I'll expand the parser to handle the other cases that come
up in the controller protocol.
---
src/core/include.am | 1 +
src/feature/control/control_cmd.c | 145 ++++++++++++++++++++++++++++--
src/feature/control/control_cmd.h | 39 ++++++++
src/feature/control/control_cmd_args_st.h | 44 +++++++++
4 files changed, 221 insertions(+), 8 deletions(-)
diff --git a/src/core/include.am b/src/core/include.am
index 982460172..b927f17a9 100644
--- a/src/core/include.am
+++ b/src/core/include.am
@@ -298,6 +298,7 @@ noinst_HEADERS += \
src/feature/control/control.h \
src/feature/control/control_auth.h \
src/feature/control/control_cmd.h \
+ src/feature/control/control_cmd_args_st.h \
src/feature/control/control_connection_st.h \
src/feature/control/control_events.h \
src/feature/control/control_fmt.h \
diff --git a/src/feature/control/control_cmd.c b/src/feature/control/control_cmd.c
index 930276b10..aa0bef513 100644
--- a/src/feature/control/control_cmd.c
+++ b/src/feature/control/control_cmd.c
@@ -45,6 +45,7 @@
#include "core/or/entry_connection_st.h"
#include "core/or/origin_circuit_st.h"
#include "core/or/socks_request_st.h"
+#include "feature/control/control_cmd_args_st.h"
#include "feature/control/control_connection_st.h"
#include "feature/nodelist/node_st.h"
#include "feature/nodelist/routerinfo_st.h"
@@ -60,6 +61,87 @@ static int control_setconf_helper(control_connection_t *conn, uint32_t len,
* finished authentication and is accepting commands. */
#define STATE_IS_OPEN(s) ((s) == CONTROL_CONN_STATE_OPEN)
+/**
+ * Release all storage held in <b>args</b>
+ **/
+void
+control_cmd_args_free_(control_cmd_args_t *args)
+{
+ if (! args)
+ return;
+
+ if (args->args) {
+ SMARTLIST_FOREACH(args->args, char *, c, tor_free(c));
+ smartlist_free(args->args);
+ }
+ tor_free(args->object);
+
+ tor_free(args);
+}
+
+/**
+ * Helper: parse the arguments to a command according to <b>syntax</b>. On
+ * success, set *<b>error_out</b> to NULL and return a newly allocated
+ * control_cmd_args_t. On failure, set *<b>error_out</b> to newly allocated
+ * error string, and return NULL.
+ **/
+STATIC control_cmd_args_t *
+control_cmd_parse_args(const char *command,
+ const control_cmd_syntax_t *syntax,
+ size_t body_len,
+ const char *body,
+ char **error_out)
+{
+ *error_out = NULL;
+ control_cmd_args_t *result = tor_malloc_zero(sizeof(control_cmd_args_t));
+ const char *cmdline;
+ char *cmdline_alloc = NULL;
+
+ result->command = command;
+
+ const char *eol = memchr(body, '\n', body_len);
+ if (syntax->want_object) {
+ if (! eol || (eol+1) == body+body_len) {
+ *error_out = tor_strdup("Empty body");
+ goto err;
+ }
+ cmdline_alloc = tor_memdup_nulterm(body, eol-body);
+ cmdline = cmdline_alloc;
+ ++eol;
+ result->object_len = read_escaped_data(eol, (body+body_len)-eol,
+ &result->object);
+ } else {
+ if (eol && (eol+1) != body+body_len) {
+ *error_out = tor_strdup("Unexpected body");
+ goto err;
+ }
+ cmdline = body;
+ }
+
+ result->args = smartlist_new();
+ smartlist_split_string(result->args, cmdline, " ",
+ SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
+ size_t n_args = smartlist_len(result->args);
+ if (n_args < syntax->min_args) {
+ tor_asprintf(error_out, "Need at least %u argument(s)",
+ syntax->min_args);
+ goto err;
+ } else if (n_args > syntax->max_args) {
+ tor_asprintf(error_out, "Cannot accept more than %u argument(s)",
+ syntax->max_args);
+ goto err;
+ }
+
+ tor_assert_nonfatal(*error_out == NULL);
+ goto done;
+ err:
+ tor_assert_nonfatal(*error_out != NULL);
+ control_cmd_args_free(result);
+ done:
+ tor_free(cmdline_alloc);
+ return result;
+}
+
/** Called when we receive a SETCONF message: parse the body and try
* to update our configuration. Reply with a DONE or ERROR message.
* Modifies the contents of body.*/
@@ -2230,7 +2312,8 @@ handle_control_obsolete(control_connection_t *conn,
**/
typedef enum handler_type_t {
hnd_legacy,
- hnd_legacy_mut
+ hnd_legacy_mut,
+ hnd_parsed,
} handler_type_t;
/**
@@ -2257,6 +2340,13 @@ typedef union handler_fn_t {
int (*legacy_mut)(control_connection_t *conn,
uint32_t arg_len,
char *args);
+
+ /**
+ * A "parsed" handler expects its arguments in a pre-parsed format, in
+ * an immutable control_cmd_args_t *object.
+ **/
+ int (*parsed)(control_connection_t *conn,
+ const control_cmd_args_t *args);
} handler_fn_t;
/**
@@ -2279,6 +2369,10 @@ typedef struct control_cmd_def_t {
* Zero or more CMD_FL_* flags, or'd together.
*/
unsigned flags;
+ /**
+ * For parsed command: a syntax description.
+ */
+ const control_cmd_syntax_t *syntax;
} control_cmd_def_t;
/**
@@ -2287,16 +2381,27 @@ typedef struct control_cmd_def_t {
*/
#define CMD_FL_WIPE (1u<<0)
-/**
- * Macro: declare a command with a one-line argument and a given set of
- * flags.
+#define SYNTAX_IGNORE { 0, UINT_MAX, false }
+
+/** Macro: declare a command with a one-line argument, a given set of flags,
+ * and a syntax definition.
**/
-#define ONE_LINE(name, htype, flags) \
+#define ONE_LINE_(name, htype, flags, syntax) \
{ #name, \
hnd_ ##htype, \
{ .htype = handle_control_ ##name }, \
- flags \
+ flags, \
+ syntax, \
}
+
+/** Macro: declare a parsed command with a one-line argument, a given set of
+ * flags, and a syntax definition.
+ **/
+#define ONE_LINE(name, htype, flags) \
+ ONE_LINE_(name, htype, flags, NULL)
+#define ONE_LINE_PARSED(name, flags, syntax) \
+ ONE_LINE_(name, parsed, flags, syntax)
+
/**
* Macro: declare a command with a multi-line argument and a given set of
* flags.
@@ -2305,7 +2410,8 @@ typedef struct control_cmd_def_t {
{ "+"#name, \
hnd_ ##htype, \
{ .htype = handle_control_ ##name }, \
- flags \
+ flags, \
+ NULL \
}
/**
* Macro: declare an obsolete command. (Obsolete commands give a different
@@ -2315,7 +2421,8 @@ typedef struct control_cmd_def_t {
{ #name, \
hnd_legacy, \
{ .legacy = handle_control_obsolete }, \
- 0 \
+ 0, \
+ NULL, \
}
/**
@@ -2379,6 +2486,28 @@ handle_single_control_command(const control_cmd_def_t *def,
if (def->handler.legacy_mut(conn, cmd_data_len, args))
rv = -1;
break;
+ case hnd_parsed: {
+ control_cmd_args_t *parsed_args;
+ char *err=NULL;
+ tor_assert(def->syntax);
+ parsed_args = control_cmd_parse_args(conn->incoming_cmd,
+ def->syntax,
+ cmd_data_len, args,
+ &err);
+ if (!parsed_args) {
+ connection_printf_to_buf(conn,
+ "512 Bad arguments to %s: %s\r\n",
+ conn->incoming_cmd, err?err:"");
+ tor_free(err);
+ } else {
+ if (BUG(err))
+ tor_free(err);
+ if (def->handler.parsed(conn, parsed_args))
+ rv = 0;
+ control_cmd_args_free(parsed_args);
+ }
+ break;
+ }
default:
tor_assert_unreached();
}
diff --git a/src/feature/control/control_cmd.h b/src/feature/control/control_cmd.h
index a417e10da..1070a9edb 100644
--- a/src/feature/control/control_cmd.h
+++ b/src/feature/control/control_cmd.h
@@ -12,11 +12,19 @@
#ifndef TOR_CONTROL_CMD_H
#define TOR_CONTROL_CMD_H
+#include "lib/malloc/malloc.h"
+
int handle_control_command(control_connection_t *conn,
uint32_t cmd_data_len,
char *args);
void control_cmd_free_all(void);
+typedef struct control_cmd_args_t control_cmd_args_t;
+void control_cmd_args_free_(control_cmd_args_t *args);
+
+#define control_cmd_args_free(v) \
+ FREE_AND_NULL(control_cmd_args_t, control_cmd_args_free_, (v))
+
#ifdef CONTROL_CMD_PRIVATE
#include "lib/crypt_ops/crypto_ed25519.h"
@@ -39,6 +47,37 @@ STATIC int add_onion_helper_keyarg(const char *arg, int discard_pk,
STATIC rend_authorized_client_t *add_onion_helper_clientauth(const char *arg,
int *created, char **err_msg_out);
+/**
+ * Definition for the syntax of a controller command, as parsed by
+ * control_cmd_parse_args.
+ *
+ * WORK IN PROGRESS: This structure is going to get more complex as this
+ * branch goes on.
+ **/
+typedef struct control_cmd_syntax_t {
+ /**
+ * Lowest number of positional arguments that this command accepts.
+ * 0 for "it's okay not to have positional arguments."
+ **/
+ unsigned int min_args;
+ /**
+ * Highest number of positional arguments that this command accepts.
+ * UINT_MAX for no limit.
+ **/
+ unsigned int max_args;
+ /**
+ * True iff this command wants to be followed by a multiline object.
+ **/
+ bool want_object;
+} control_cmd_syntax_t;
+
+STATIC control_cmd_args_t *control_cmd_parse_args(
+ const char *command,
+ const control_cmd_syntax_t *syntax,
+ size_t body_len,
+ const char *body,
+ char **error_out);
+
#endif /* defined(CONTROL_CMD_PRIVATE) */
#ifdef CONTROL_MODULE_PRIVATE
diff --git a/src/feature/control/control_cmd_args_st.h b/src/feature/control/control_cmd_args_st.h
new file mode 100644
index 000000000..9ecc5d750
--- /dev/null
+++ b/src/feature/control/control_cmd_args_st.h
@@ -0,0 +1,44 @@
+/* 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 control_cmd_args_st.h
+ * \brief Definition for control_cmd_args_t
+ **/
+
+#ifndef TOR_CONTROL_CMD_ST_H
+#define TOR_CONTROL_CMD_ST_H
+
+struct smartlist_t;
+struct config_line_t;
+
+/**
+ * Parsed arguments for a control command.
+ *
+ * WORK IN PROGRESS: This structure is going to get more complex as this
+ * branch goes on.
+ **/
+struct control_cmd_args_t {
+ /**
+ * The command itself, as provided by the controller. Not owned by this
+ * structure.
+ **/
+ const char *command;
+ /**
+ * Positional arguments to the command.
+ **/
+ struct smartlist_t *args;
+ /**
+ * Number of bytes in <b>object</b>; 0 if <b>object</b> is not set.
+ **/
+ size_t object_len;
+ /**
+ * A multiline object passed with this command.
+ **/
+ char *object;
+};
+
+#endif /* !defined(TOR_CONTROL_CMD_ST_H) */
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