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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.
This commit is contained in:
Nick Mathewson
parent
e9ca904dbf
commit
de70eebc65
@ -298,6 +298,7 @@ noinst_HEADERS += \
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src/feature/control/control.h \
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src/feature/control/control_auth.h \
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src/feature/control/control_cmd.h \
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src/feature/control/control_cmd_args_st.h \
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src/feature/control/control_connection_st.h \
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src/feature/control/control_events.h \
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src/feature/control/control_fmt.h \
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@ -45,6 +45,7 @@
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#include "core/or/entry_connection_st.h"
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#include "core/or/origin_circuit_st.h"
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#include "core/or/socks_request_st.h"
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#include "feature/control/control_cmd_args_st.h"
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#include "feature/control/control_connection_st.h"
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#include "feature/nodelist/node_st.h"
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#include "feature/nodelist/routerinfo_st.h"
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@ -60,6 +61,87 @@ static int control_setconf_helper(control_connection_t *conn, uint32_t len,
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* finished authentication and is accepting commands. */
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#define STATE_IS_OPEN(s) ((s) == CONTROL_CONN_STATE_OPEN)
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/**
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* Release all storage held in <b>args</b>
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**/
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void
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control_cmd_args_free_(control_cmd_args_t *args)
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{
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if (! args)
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return;
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if (args->args) {
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SMARTLIST_FOREACH(args->args, char *, c, tor_free(c));
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smartlist_free(args->args);
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}
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tor_free(args->object);
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tor_free(args);
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}
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/**
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* Helper: parse the arguments to a command according to <b>syntax</b>. On
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* success, set *<b>error_out</b> to NULL and return a newly allocated
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* control_cmd_args_t. On failure, set *<b>error_out</b> to newly allocated
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* error string, and return NULL.
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**/
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STATIC control_cmd_args_t *
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control_cmd_parse_args(const char *command,
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const control_cmd_syntax_t *syntax,
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size_t body_len,
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const char *body,
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char **error_out)
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{
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*error_out = NULL;
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control_cmd_args_t *result = tor_malloc_zero(sizeof(control_cmd_args_t));
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const char *cmdline;
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char *cmdline_alloc = NULL;
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result->command = command;
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const char *eol = memchr(body, '\n', body_len);
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if (syntax->want_object) {
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if (! eol || (eol+1) == body+body_len) {
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*error_out = tor_strdup("Empty body");
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goto err;
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}
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cmdline_alloc = tor_memdup_nulterm(body, eol-body);
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cmdline = cmdline_alloc;
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++eol;
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result->object_len = read_escaped_data(eol, (body+body_len)-eol,
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&result->object);
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} else {
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if (eol && (eol+1) != body+body_len) {
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*error_out = tor_strdup("Unexpected body");
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goto err;
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}
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cmdline = body;
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}
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result->args = smartlist_new();
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smartlist_split_string(result->args, cmdline, " ",
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SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
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size_t n_args = smartlist_len(result->args);
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if (n_args < syntax->min_args) {
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tor_asprintf(error_out, "Need at least %u argument(s)",
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syntax->min_args);
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goto err;
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} else if (n_args > syntax->max_args) {
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tor_asprintf(error_out, "Cannot accept more than %u argument(s)",
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syntax->max_args);
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goto err;
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}
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tor_assert_nonfatal(*error_out == NULL);
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goto done;
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err:
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tor_assert_nonfatal(*error_out != NULL);
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control_cmd_args_free(result);
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done:
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tor_free(cmdline_alloc);
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return result;
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}
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/** Called when we receive a SETCONF message: parse the body and try
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* to update our configuration. Reply with a DONE or ERROR message.
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* Modifies the contents of body.*/
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@ -2230,7 +2312,8 @@ handle_control_obsolete(control_connection_t *conn,
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**/
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typedef enum handler_type_t {
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hnd_legacy,
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hnd_legacy_mut
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hnd_legacy_mut,
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hnd_parsed,
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} handler_type_t;
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/**
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@ -2257,6 +2340,13 @@ typedef union handler_fn_t {
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int (*legacy_mut)(control_connection_t *conn,
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uint32_t arg_len,
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char *args);
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/**
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* A "parsed" handler expects its arguments in a pre-parsed format, in
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* an immutable control_cmd_args_t *object.
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**/
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int (*parsed)(control_connection_t *conn,
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const control_cmd_args_t *args);
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} handler_fn_t;
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/**
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@ -2279,6 +2369,10 @@ typedef struct control_cmd_def_t {
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* Zero or more CMD_FL_* flags, or'd together.
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*/
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unsigned flags;
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/**
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* For parsed command: a syntax description.
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*/
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const control_cmd_syntax_t *syntax;
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} control_cmd_def_t;
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/**
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@ -2287,16 +2381,27 @@ typedef struct control_cmd_def_t {
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*/
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#define CMD_FL_WIPE (1u<<0)
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/**
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* Macro: declare a command with a one-line argument and a given set of
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* flags.
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#define SYNTAX_IGNORE { 0, UINT_MAX, false }
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/** Macro: declare a command with a one-line argument, a given set of flags,
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* and a syntax definition.
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**/
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#define ONE_LINE(name, htype, flags) \
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#define ONE_LINE_(name, htype, flags, syntax) \
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{ #name, \
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hnd_ ##htype, \
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{ .htype = handle_control_ ##name }, \
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flags \
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flags, \
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syntax, \
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}
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/** Macro: declare a parsed command with a one-line argument, a given set of
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* flags, and a syntax definition.
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**/
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#define ONE_LINE(name, htype, flags) \
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ONE_LINE_(name, htype, flags, NULL)
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#define ONE_LINE_PARSED(name, flags, syntax) \
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ONE_LINE_(name, parsed, flags, syntax)
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/**
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* Macro: declare a command with a multi-line argument and a given set of
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* flags.
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@ -2305,7 +2410,8 @@ typedef struct control_cmd_def_t {
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{ "+"#name, \
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hnd_ ##htype, \
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{ .htype = handle_control_ ##name }, \
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flags \
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flags, \
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NULL \
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}
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/**
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* Macro: declare an obsolete command. (Obsolete commands give a different
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@ -2315,7 +2421,8 @@ typedef struct control_cmd_def_t {
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{ #name, \
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hnd_legacy, \
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{ .legacy = handle_control_obsolete }, \
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0 \
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0, \
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NULL, \
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}
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/**
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@ -2379,6 +2486,28 @@ handle_single_control_command(const control_cmd_def_t *def,
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if (def->handler.legacy_mut(conn, cmd_data_len, args))
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rv = -1;
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break;
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case hnd_parsed: {
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control_cmd_args_t *parsed_args;
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char *err=NULL;
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tor_assert(def->syntax);
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parsed_args = control_cmd_parse_args(conn->incoming_cmd,
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def->syntax,
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cmd_data_len, args,
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&err);
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if (!parsed_args) {
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connection_printf_to_buf(conn,
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"512 Bad arguments to %s: %s\r\n",
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conn->incoming_cmd, err?err:"");
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tor_free(err);
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} else {
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if (BUG(err))
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tor_free(err);
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if (def->handler.parsed(conn, parsed_args))
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rv = 0;
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control_cmd_args_free(parsed_args);
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}
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break;
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}
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default:
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tor_assert_unreached();
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}
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@ -12,11 +12,19 @@
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#ifndef TOR_CONTROL_CMD_H
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#define TOR_CONTROL_CMD_H
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#include "lib/malloc/malloc.h"
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int handle_control_command(control_connection_t *conn,
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uint32_t cmd_data_len,
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char *args);
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void control_cmd_free_all(void);
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typedef struct control_cmd_args_t control_cmd_args_t;
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void control_cmd_args_free_(control_cmd_args_t *args);
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#define control_cmd_args_free(v) \
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FREE_AND_NULL(control_cmd_args_t, control_cmd_args_free_, (v))
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#ifdef CONTROL_CMD_PRIVATE
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#include "lib/crypt_ops/crypto_ed25519.h"
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@ -39,6 +47,37 @@ STATIC int add_onion_helper_keyarg(const char *arg, int discard_pk,
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STATIC rend_authorized_client_t *add_onion_helper_clientauth(const char *arg,
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int *created, char **err_msg_out);
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/**
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* Definition for the syntax of a controller command, as parsed by
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* control_cmd_parse_args.
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*
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* WORK IN PROGRESS: This structure is going to get more complex as this
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* branch goes on.
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**/
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typedef struct control_cmd_syntax_t {
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/**
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* Lowest number of positional arguments that this command accepts.
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* 0 for "it's okay not to have positional arguments."
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**/
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unsigned int min_args;
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/**
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* Highest number of positional arguments that this command accepts.
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* UINT_MAX for no limit.
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**/
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unsigned int max_args;
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/**
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* True iff this command wants to be followed by a multiline object.
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**/
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bool want_object;
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} control_cmd_syntax_t;
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STATIC control_cmd_args_t *control_cmd_parse_args(
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const char *command,
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const control_cmd_syntax_t *syntax,
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size_t body_len,
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const char *body,
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char **error_out);
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#endif /* defined(CONTROL_CMD_PRIVATE) */
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#ifdef CONTROL_MODULE_PRIVATE
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44
src/feature/control/control_cmd_args_st.h
Normal file
44
src/feature/control/control_cmd_args_st.h
Normal file
@ -0,0 +1,44 @@
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/* Copyright (c) 2001 Matej Pfajfar.
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* Copyright (c) 2001-2004, Roger Dingledine.
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* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
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* Copyright (c) 2007-2019, The Tor Project, Inc. */
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/* See LICENSE for licensing information */
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/**
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* \file control_cmd_args_st.h
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* \brief Definition for control_cmd_args_t
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**/
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#ifndef TOR_CONTROL_CMD_ST_H
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#define TOR_CONTROL_CMD_ST_H
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struct smartlist_t;
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struct config_line_t;
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/**
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* Parsed arguments for a control command.
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*
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* WORK IN PROGRESS: This structure is going to get more complex as this
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* branch goes on.
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**/
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struct control_cmd_args_t {
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/**
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* The command itself, as provided by the controller. Not owned by this
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* structure.
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**/
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const char *command;
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/**
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* Positional arguments to the command.
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**/
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struct smartlist_t *args;
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/**
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* Number of bytes in <b>object</b>; 0 if <b>object</b> is not set.
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**/
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size_t object_len;
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/**
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* A multiline object passed with this command.
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**/
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char *object;
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};
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#endif /* !defined(TOR_CONTROL_CMD_ST_H) */
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