Initial commit

1 files changed, 724 insertions, 0 deletions

diff --git a/json-rpc-shell.c b/json-rpc-shell.c
new file mode 100644
index 0000000..554d91d
--- /dev/null
+++ b/json-rpc-shell.c
@@ -0,0 +1,724 @@
+/*
+ * json-rpc-shell.c: trivial JSON-RPC 2.0 shell
+ *
+ * Copyright (c) 2014, Přemysl Janouch <p.janouch@gmail.com>
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#define PROGRAM_NAME "json-rpc-shell"
+#define PROGRAM_VERSION "alpha"
+
+/// Some arbitrary limit for the history file
+#define HISTORY_LIMIT 10000
+
+#define _POSIX_C_SOURCE 199309L
+#define _XOPEN_SOURCE 600
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+#include <locale.h>
+#include <errno.h>
+
+#include <libgen.h>
+#include <iconv.h>
+#include <langinfo.h>
+#include <sys/stat.h>
+
+#include <getopt.h>
+#include <readline/readline.h>
+#include <readline/history.h>
+#include <curl/curl.h>
+#include <jansson.h>
+
+#if defined __GNUC__
+#define ATTRIBUTE_PRINTF(x, y) __attribute__ ((format (printf, x, y)))
+#else // ! __GNUC__
+#define ATTRIBUTE_PRINTF(x, y)
+#endif // ! __GNUC__
+
+#define N_ELEMENTS(a) (sizeof (a) / sizeof ((a)[0]))
+
+#define BLOCK_START  do {
+#define BLOCK_END    } while (0)
+
+// --- Logging -----------------------------------------------------------------
+
+static void
+log_message_stdio (const char *quote, const char *fmt, va_list ap)
+{
+	FILE *stream = stderr;
+
+	fputs (quote, stream);
+	vfprintf (stream, fmt, ap);
+	fputs ("\n", stream);
+}
+
+static void
+log_message (const char *quote, const char *fmt, ...) ATTRIBUTE_PRINTF (2, 3);
+
+static void
+log_message (const char *quote, const char *fmt, ...)
+{
+	va_list ap;
+	va_start (ap, fmt);
+	log_message_stdio (quote, fmt, ap);
+	va_end (ap);
+}
+
+// `fatal' is reserved for unexpected failures that would harm further operation
+
+#define print_fatal(...)    log_message ("fatal: ",   __VA_ARGS__)
+#define print_error(...)    log_message ("error: ",   __VA_ARGS__)
+#define print_warning(...)  log_message ("warning: ", __VA_ARGS__)
+#define print_status(...)   log_message ("-- ",       __VA_ARGS__)
+
+#define exit_fatal(...)                                                        \
+	BLOCK_START                                                                \
+		print_fatal (__VA_ARGS__);                                             \
+		exit (EXIT_FAILURE);                                                   \
+	BLOCK_END
+
+// --- Dynamically allocated strings -------------------------------------------
+
+// Basically a string builder to abstract away manual memory management.
+
+struct str
+{
+	char *str;                          ///< String data, null terminated
+	size_t alloc;                       ///< How many bytes are allocated
+	size_t len;                         ///< How long the string actually is
+};
+
+static void
+str_init (struct str *self)
+{
+	self->alloc = 16;
+	self->len = 0;
+	self->str = strcpy (malloc (self->alloc), "");
+}
+
+static void
+str_free (struct str *self)
+{
+	free (self->str);
+	self->str = NULL;
+	self->alloc = 0;
+	self->len = 0;
+}
+
+static void
+str_ensure_space (struct str *self, size_t n)
+{
+	// We allocate at least one more byte for the terminating null character
+	size_t new_alloc = self->alloc;
+	while (new_alloc <= self->len + n)
+		new_alloc <<= 1;
+	if (new_alloc != self->alloc)
+		self->str = realloc (self->str, (self->alloc = new_alloc));
+}
+
+static void
+str_append_data (struct str *self, const char *data, size_t n)
+{
+	str_ensure_space (self, n);
+	memcpy (self->str + self->len, data, n);
+	self->len += n;
+	self->str[self->len] = '\0';
+}
+
+static void
+str_append_c (struct str *self, char c)
+{
+	str_append_data (self, &c, 1);
+}
+
+static void
+str_append (struct str *self, const char *s)
+{
+	str_append_data (self, s, strlen (s));
+}
+
+// --- Utilities ---------------------------------------------------------------
+
+static char *strdup_printf (const char *format, ...) ATTRIBUTE_PRINTF (1, 2);
+
+static char *
+strdup_printf (const char *format, ...)
+{
+	va_list ap;
+	va_start (ap, format);
+	int size = vsnprintf (NULL, 0, format, ap);
+	va_end (ap);
+	if (size < 0)
+		return NULL;
+
+	char buf[size + 1];
+	va_start (ap, format);
+	size = vsnprintf (buf, sizeof buf, format, ap);
+	va_end (ap);
+	if (size < 0)
+		return NULL;
+
+	return strdup (buf);
+}
+
+static char *
+iconv_strdup (iconv_t conv, char *in, size_t in_len, size_t *out_len)
+{
+	char *buf, *buf_ptr;
+	size_t out_left, buf_alloc;
+
+	buf = buf_ptr = malloc (out_left = buf_alloc = 64);
+
+	char *in_ptr = in;
+	if (in_len == (size_t) -1)
+		in_len = strlen (in) + 1;
+
+	while (iconv (conv, (char **) &in_ptr, &in_len,
+		(char **) &buf_ptr, &out_left) == (size_t) -1)
+	{
+		if (errno != E2BIG)
+		{
+			free (buf);
+			return NULL;
+		}
+		out_left += buf_alloc;
+		char *new_buf = realloc (buf, buf_alloc <<= 1);
+		buf_ptr += new_buf - buf;
+		buf = new_buf;
+	}
+	if (out_len)
+		*out_len = buf_alloc - out_left;
+	return buf;
+}
+
+static bool
+ensure_directory_existence (const char *path)
+{
+	struct stat st;
+	if (stat (path, &st))
+	{
+		if (mkdir (path, S_IRWXU | S_IRWXG | S_IRWXO))
+			return false;
+	}
+	else if (!S_ISDIR (st.st_mode))
+		return false;
+	return true;
+}
+
+static bool
+mkdir_with_parents (char *path)
+{
+	char *p = path;
+	while ((p = strchr (p + 1, '/')))
+	{
+		*p = '\0';
+		bool success = ensure_directory_existence (path);
+		*p = '/';
+
+		if (!success)
+			return false;
+	}
+	return ensure_directory_existence (path);
+}
+
+// --- Main program ------------------------------------------------------------
+
+struct app_context
+{
+	CURL *curl;                         ///< cURL handle
+	char curl_error[CURL_ERROR_SIZE];   ///< cURL error info buffer
+
+	bool pretty_print;                  ///< Whether to pretty print
+	bool verbose;                       ///< Print requests
+	bool trust_all;                     ///< Don't verify peer certificates
+
+	bool auto_id;                       ///< Use automatically generated ID's
+	int64_t next_id;                    ///< Next autogenerated ID
+
+	iconv_t term_to_utf8;               ///< Terminal encoding to UTF-8
+	iconv_t term_from_utf8;             ///< UTF-8 to terminal encoding
+};
+
+#define PARSE_FAIL(...)                                                        \
+	BLOCK_START                                                                \
+		print_error (__VA_ARGS__);                                             \
+		goto fail;                                                             \
+	BLOCK_END
+
+static bool
+parse_response (struct app_context *ctx, struct str *buf)
+{
+	json_error_t e;
+	json_t *response;
+	if (!(response = json_loadb (buf->str, buf->len, JSON_DECODE_ANY, &e)))
+	{
+		print_error ("failed to parse the response: %s", e.text);
+		return false;
+	}
+
+	bool success = false;
+	if (!json_is_object (response))
+		PARSE_FAIL ("the response is not a JSON object");
+
+	json_t *v;
+	if (!(v = json_object_get (response, "jsonrpc")))
+		print_warning ("`%s' field not present in response", "jsonrpc");
+	else if (!json_is_string (v) || strcmp (json_string_value (v), "2.0"))
+		print_warning ("invalid `%s' field in response", "jsonrpc");
+
+	json_t *result = json_object_get (response, "result");
+	json_t *error  = json_object_get (response, "error");
+	json_t *data   = NULL;
+
+	if (!result && !error)
+		PARSE_FAIL ("neither `result' nor `error' present in response");
+	if (result && error)
+		// Prohibited by the specification but happens in real life (null)
+		print_warning ("both `result' and `error' present in response");
+
+	if (error)
+	{
+		if (!json_is_object (error))
+			PARSE_FAIL ("invalid `%s' field in response", "error");
+
+		json_t *code    = json_object_get (error, "code");
+		json_t *message = json_object_get (error, "message");
+
+		if (!code)
+			PARSE_FAIL ("missing `%s' field in error response", "code");
+		if (!message)
+			PARSE_FAIL ("missing `%s' field in error response", "message");
+
+		if (!json_is_integer (code))
+			PARSE_FAIL ("invalid `%s' field in error response", "code");
+		if (!json_is_string (message))
+			PARSE_FAIL ("invalid `%s' field in error response", "message");
+
+		json_int_t code_val = json_integer_value (code);
+		char *utf8 = strdup_printf ("error response: %" JSON_INTEGER_FORMAT
+			" (%s)", code_val, json_string_value (message));
+		char *s = iconv_strdup (ctx->term_from_utf8, utf8, -1, NULL);
+		if (!s)
+			print_error ("character conversion failed for `%s'", "error");
+		else
+			printf ("%s\n", s);
+		free (s);
+
+		data = json_object_get (error, "data");
+	}
+
+	if (data)
+	{
+		char *utf8 = json_dumps (data, JSON_ENCODE_ANY);
+		char *s = iconv_strdup (ctx->term_from_utf8, utf8, -1, NULL);
+		free (utf8);
+
+		if (!s)
+			print_error ("character conversion failed for `%s'", "error data");
+		else
+			printf ("error data: %s\n", s);
+		free (s);
+	}
+
+	if (result)
+	{
+		int flags = JSON_ENCODE_ANY;
+		if (ctx->pretty_print)
+			flags |= JSON_INDENT (2);
+
+		char *utf8 = json_dumps (result, flags);
+		char *s = iconv_strdup (ctx->term_from_utf8, utf8, -1, NULL);
+		free (utf8);
+
+		if (!s)
+			print_error ("character conversion failed for `%s'", "result");
+		else
+			printf ("result: %s\n", s);
+		free (s);
+	}
+
+	success = true;
+fail:
+	json_decref (response);
+	return success;
+}
+
+static bool
+is_valid_json_rpc_id (json_t *v)
+{
+	return json_is_string (v) || json_is_integer (v)
+		|| json_is_real (v) || json_is_null (v);  // These two shouldn't be used
+}
+
+static bool
+is_valid_json_rpc_params (json_t *v)
+{
+	return json_is_array (v) || json_is_object (v);
+}
+
+static bool
+isspace_ascii (int c)
+{
+	return strchr (" \f\n\r\t\v", c);
+}
+
+static size_t
+write_callback (char *ptr, size_t size, size_t nmemb, void *user_data)
+{
+	struct str *buf = user_data;
+	str_append_data (buf, ptr, size * nmemb);
+	return size * nmemb;
+}
+
+#define RPC_FAIL(...)                                                          \
+	BLOCK_START                                                                \
+		print_error (__VA_ARGS__);                                             \
+		goto fail;                                                             \
+	BLOCK_END
+
+static void
+make_json_rpc_call (struct app_context *ctx,
+	const char *method, json_t *id, json_t *params)
+{
+	json_t *request = json_object ();
+	json_object_set_new (request, "jsonrpc", json_string ("2.0"));
+	json_object_set_new (request, "method",  json_string (method));
+
+	if (id)      json_object_set (request, "id",     id);
+	if (params)  json_object_set (request, "params", params);
+
+	char *req_utf8 = json_dumps (request, 0);
+	if (ctx->verbose)
+	{
+		char *req_term = iconv_strdup (ctx->term_from_utf8, req_utf8, -1, NULL);
+		if (!req_term)
+			print_error ("%s: %s", "verbose", "character conversion failed");
+		else
+			printf ("%s\n", req_term);
+		free (req_term);
+	}
+
+	struct str buf;
+	str_init (&buf);
+
+	if (curl_easy_setopt (ctx->curl, CURLOPT_POSTFIELDS, req_utf8)
+	 || curl_easy_setopt (ctx->curl, CURLOPT_POSTFIELDSIZE_LARGE,
+		(curl_off_t) -1)
+	 || curl_easy_setopt (ctx->curl, CURLOPT_WRITEDATA, &buf)
+	 || curl_easy_setopt (ctx->curl, CURLOPT_WRITEFUNCTION, write_callback))
+		RPC_FAIL ("cURL setup failed");
+
+	CURLcode ret;
+	if ((ret = curl_easy_perform (ctx->curl)))
+		RPC_FAIL ("HTTP request failed: %s", ctx->curl_error);
+
+	long code;
+	char *type;
+	if (curl_easy_getinfo (ctx->curl, CURLINFO_RESPONSE_CODE, &code)
+	 || curl_easy_getinfo (ctx->curl, CURLINFO_CONTENT_TYPE, &type))
+		RPC_FAIL ("cURL info retrieval failed");
+
+	if (code != 200)
+		RPC_FAIL ("unexpected HTTP response code: %ld", code);
+
+	bool success = false;
+	if (id)
+	{
+		if (!type)
+			print_warning ("missing `Content-Type' header");
+		else if (strcmp (type, "application/json"))
+			// FIXME: expect e.g. application/json; charset=UTF-8
+			print_warning ("unexpected `Content-Type' header: %s", type);
+
+		success = parse_response (ctx, &buf);
+	}
+	else
+	{
+		printf ("[Notification]\n");
+		if (buf.len)
+			print_warning ("we have been sent data back for a notification");
+		else
+			success = true;
+	}
+
+	if (!success)
+	{
+		char *s = iconv_strdup (ctx->term_from_utf8,
+			buf.str, buf.len + 1, NULL);
+		if (!s)
+			print_error ("character conversion failed for `%s'",
+				"raw response data");
+		else
+			printf ("%s: %s\n", "raw response data", s);
+		free (s);
+	}
+fail:
+	str_free (&buf);
+	free (req_utf8);
+	json_decref (request);
+}
+
+static void
+process_input (struct app_context *ctx, char *user_input)
+{
+	char *input;
+	size_t len;
+
+	if (!(input = iconv_strdup (ctx->term_to_utf8, user_input, -1, &len)))
+	{
+		print_error ("character conversion failed for `%s'", "user input");
+		goto fail;
+	}
+
+	// Cut out the method name first
+	char *p = input;
+	while (*p && isspace_ascii (*p))
+		p++;
+	char *method = p;
+	while (*p && !isspace_ascii (*p))
+		p++;
+	if (*p)
+		*p++ = '\0';
+
+	// Now we go through this madness, just so that the order can be arbitrary
+	json_error_t e;
+	size_t args_len = 0;
+	json_t *args[2], *id = NULL, *params = NULL;
+
+	while (true)
+	{
+		// Jansson is too stupid to just tell us that there was nothing
+		while (*p && isspace_ascii (*p))
+			p++;
+		if (!*p)
+			break;
+
+		if (args_len == N_ELEMENTS (args))
+		{
+			print_error ("too many arguments");
+			goto fail_tokener;
+		}
+		if (!(args[args_len] = json_loadb (p, len - (p - input),
+			JSON_DECODE_ANY | JSON_DISABLE_EOF_CHECK, &e)))
+		{
+			print_error ("failed to parse JSON value: %s", e.text);
+			goto fail_tokener;
+		}
+		p += e.position;
+		args_len++;
+	}
+
+	for (size_t i = 0; i < args_len; i++)
+	{
+		if (is_valid_json_rpc_id (args[i]))
+			id = json_incref (args[i]);
+		else if (is_valid_json_rpc_params (args[i]))
+			params = json_incref (args[i]);
+		else
+		{
+			print_error ("unexpected value at index %zu", i);
+			goto fail_tokener;
+		}
+	}
+
+	if (!id && ctx->auto_id)
+		id = json_integer (ctx->next_id++);
+
+	make_json_rpc_call (ctx, method, id, params);
+
+fail_tokener:
+	if (id)      json_decref (id);
+	if (params)  json_decref (params);
+
+	for (size_t i = 0; i < args_len; i++)
+		json_decref (args[i]);
+fail:
+	free (input);
+	putchar ('\n');
+}
+
+static void
+print_usage (const char *program_name)
+{
+	fprintf (stderr,
+		"Usage: %s [OPTION]... ENDPOINT\n"
+		"Trivial JSON-RPC shell.\n"
+		"\n"
+		"  -h, --help       display this help and exit\n"
+		"  -V, --version    output version information and exit\n"
+		"  -a, --auto-id    automatic `id' fields\n"
+		"  -o, --origin O   set the HTTP Origin header\n"
+		"  -p, --pretty     pretty-print the responses\n"
+		"  -t, --trust-all  don't care about SSL/TLS certificates\n"
+		"  -v, --verbose    print the request before sending\n",
+		program_name);
+}
+
+int
+main (int argc, char *argv[])
+{
+	const char *invocation_name = argv[0];
+
+	struct app_context ctx;
+	memset (&ctx, 0, sizeof ctx);
+
+	static struct option opts[] =
+	{
+		{ "help",      no_argument,       NULL, 'h' },
+		{ "version",   no_argument,       NULL, 'V' },
+		{ "auto-id",   no_argument,       NULL, 'a' },
+		{ "origin",    required_argument, NULL, 'o' },
+		{ "pretty",    no_argument,       NULL, 'p' },
+		{ "trust-all", no_argument,       NULL, 't' },
+		{ "verbose",   no_argument,       NULL, 'v' },
+		{ NULL,        0,                 NULL,  0  }
+	};
+
+	char *origin = NULL;
+	while (1)
+	{
+		int c, opt_index;
+
+		c = getopt_long (argc, argv, "hVapvt", opts, &opt_index);
+		if (c == -1)
+			break;
+
+		switch (c)
+		{
+		case 'h':
+			print_usage (invocation_name);
+			exit (EXIT_SUCCESS);
+		case 'V':
+			printf (PROGRAM_NAME " " PROGRAM_VERSION "\n");
+			exit (EXIT_SUCCESS);
+
+		case 'a':  ctx.auto_id      = true;  break;
+		case 'o':  origin = optarg;          break;
+		case 'p':  ctx.pretty_print = true;  break;
+		case 't':  ctx.trust_all    = true;  break;
+		case 'v':  ctx.verbose      = true;  break;
+
+		default:
+			print_error ("wrong options");
+			exit (EXIT_FAILURE);
+		}
+	}
+
+	argv += optind;
+	argc -= optind;
+
+	if (argc != 1)
+	{
+		print_usage (invocation_name);
+		exit (EXIT_FAILURE);
+	}
+
+	const char *endpoint = argv[0];
+	if (strncmp (endpoint, "http://", 7)
+	 && strncmp (endpoint, "https://", 8))
+		exit_fatal ("the endpoint address must begin with"
+			" either `http://' or `https://'");
+
+	CURL *curl;
+	if (!(ctx.curl = curl = curl_easy_init ()))
+		exit_fatal ("cURL initialization failed");
+
+	struct curl_slist *headers = NULL;
+	headers = curl_slist_append (headers, "Content-Type: application/json");
+
+	if (origin)
+	{
+		origin = strdup_printf ("Origin: %s", origin);
+		headers = curl_slist_append (headers, origin);
+	}
+
+	if (curl_easy_setopt (curl, CURLOPT_POST,           1L)
+	 || curl_easy_setopt (curl, CURLOPT_NOPROGRESS,     1L)
+	 || curl_easy_setopt (curl, CURLOPT_ERRORBUFFER,    ctx.curl_error)
+	 || curl_easy_setopt (curl, CURLOPT_HTTPHEADER,     headers)
+	 || curl_easy_setopt (curl, CURLOPT_SSL_VERIFYPEER, ctx.trust_all ? 0L : 1L)
+	 || curl_easy_setopt (curl, CURLOPT_SSL_VERIFYHOST, ctx.trust_all ? 0L : 2L)
+	 || curl_easy_setopt (curl, CURLOPT_URL,            endpoint))
+		exit_fatal ("cURL setup failed");
+
+	// We only need to convert to and from the terminal encoding
+	setlocale (LC_CTYPE, "");
+
+	char *encoding = nl_langinfo (CODESET);
+#ifdef __linux__
+	// XXX: not quite sure if this is actually desirable
+	encoding = strdup_printf ("%s//TRANSLIT", encoding);
+#endif // __linux__
+
+	if ((ctx.term_from_utf8 = iconv_open (encoding, "utf-8"))
+		== (iconv_t) -1
+	 || (ctx.term_to_utf8 = iconv_open ("utf-8", nl_langinfo (CODESET)))
+		== (iconv_t) -1)
+		exit_fatal ("creating the UTF-8 conversion object failed: %s",
+			strerror (errno));
+
+	char *data_home = getenv ("XDG_DATA_HOME"), *home = getenv ("HOME");
+	if (!data_home || *data_home != '/')
+	{
+		if (!home)
+			exit_fatal ("where is your $HOME, kid?");
+
+		data_home = strdup_printf ("%s/.local/share", home);
+	}
+
+	using_history ();
+	stifle_history (HISTORY_LIMIT);
+
+	char *history_path =
+		strdup_printf ("%s/" PROGRAM_NAME "/history", data_home);
+	(void) read_history (history_path);
+
+	// XXX: we should use termcap/terminfo for the codes but who cares
+	char *prompt = strdup_printf ("%c\x1b[1m%cjson-rpc> %c\x1b[0m%c",
+		RL_PROMPT_START_IGNORE, RL_PROMPT_END_IGNORE,
+		RL_PROMPT_START_IGNORE, RL_PROMPT_END_IGNORE);
+
+	char *line;
+	while ((line = readline (prompt)))
+	{
+		if (*line)
+			add_history (line);
+
+		process_input (&ctx, line);
+		free (line);
+	}
+
+	char *dir = strdup (history_path);
+	(void) mkdir_with_parents (dirname (dir));
+	free (dir);
+
+	if (write_history (history_path))
+		print_error ("writing the history file `%s' failed: %s",
+			history_path, strerror (errno));
+
+	free (history_path);
+	iconv_close (ctx.term_from_utf8);
+	iconv_close (ctx.term_to_utf8);
+	curl_slist_free_all (headers);
+	free (origin);
+	curl_easy_cleanup (curl);
+	return EXIT_SUCCESS;
+}