parsers: avoid NULL dereference when option strings are empty

[sigrok-cli.git] / input.c

/*
 * This file is part of the sigrok-cli project.
 *
 * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#include "sigrok-cli.h"

#define CHUNK_SIZE (4 * 1024 * 1024)

static void load_input_file_module(struct df_arg_desc *df_arg)
{
	struct sr_session *session;
	const struct sr_input *in;
	const struct sr_input_module *imod;
	const struct sr_option **options;
	struct sr_dev_inst *sdi;
	GHashTable *mod_args, *mod_opts;
	GString *buf;
	gboolean got_sdi;
	int fd;
	ssize_t len;
	char *mod_id;
	gboolean is_stdin;
	gboolean push_scan_data;

	if (!sr_input_list())
		g_critical("No supported input formats available.");

	mod_id = NULL;
	mod_args = NULL;
	if (opt_input_format) {
		mod_args = parse_generic_arg(opt_input_format, TRUE, NULL);
		mod_id = g_hash_table_lookup(mod_args, "sigrok_key");
	}

	is_stdin = strcmp(opt_input_file, "-") == 0;
	push_scan_data = FALSE;
	fd = 0;
	buf = g_string_sized_new(CHUNK_SIZE);
	if (mod_id) {
		/* User specified an input module to use. */
		if (!(imod = sr_input_find(mod_id)))
			g_critical("Error: unknown input module '%s'.", mod_id);
		g_hash_table_remove(mod_args, "sigrok_key");
		if ((options = sr_input_options_get(imod))) {
			mod_opts = generic_arg_to_opt(options, mod_args);
			(void)warn_unknown_keys(options, mod_args, NULL);
			sr_input_options_free(options);
		} else {
			mod_opts = NULL;
		}
		if (!(in = sr_input_new(imod, mod_opts)))
			g_critical("Error: failed to initialize input module.");
		if (mod_opts)
			g_hash_table_destroy(mod_opts);
		if (mod_args)
			g_hash_table_destroy(mod_args);
		if (!is_stdin && (fd = open(opt_input_file, O_RDONLY)) < 0)
			g_critical("Failed to load %s: %s.", opt_input_file,
					g_strerror(errno));
	} else {
		if (!is_stdin) {
			/*
			 * An actual filename: let the input modules try to
			 * identify the file.
			 */
			if (sr_input_scan_file(opt_input_file, &in) == SR_OK) {
				/* That worked, reopen the file for reading. */
				fd = open(opt_input_file, O_RDONLY);
			}
		} else {
			/*
			 * Taking input from a pipe: let the input modules try
			 * to identify the stream content.
			 */
			if (is_stdin) {
				/* stdin */
				fd = 0;
			} else {
				fd = open(opt_input_file, O_RDONLY);
				if (fd == -1)
					g_critical("Failed to load %s: %s.", opt_input_file,
							g_strerror(errno));
			}
			if ((len = read(fd, buf->str, buf->allocated_len)) < 1)
				g_critical("Failed to read %s: %s.", opt_input_file,
						g_strerror(errno));
			buf->len = len;
			sr_input_scan_buffer(buf, &in);
			push_scan_data = TRUE;
		}
		if (!in)
			g_critical("Error: no input module found for this file.");
	}
	sr_session_new(sr_ctx, &session);
	df_arg->session = session;
	sr_session_datafeed_callback_add(session, datafeed_in, df_arg);

	/*
	 * Implementation detail: The combination of reading from stdin
	 * and automatic file format detection may have pushed the first
	 * chunk of input data into the input module's data accumulator,
	 * _bypassing_ the .receive() callback. It is essential to call
	 * .receive() before calling .end() for files of size smaller than
	 * CHUNK_SIZE (which is a typical case). So that sdi becomes ready.
	 * Fortunately all input modules accept .receive() calls with
	 * a zero length, and inspect whatever was accumulated so far.
	 *
	 * After that optional initial push of data which was queued
	 * above during format detection, continue reading remaining
	 * chunks from the input file until EOF is seen.
	 */
	got_sdi = FALSE;
	while (TRUE) {
		g_string_truncate(buf, 0);
		if (push_scan_data)
			len = 0;
		else
			len = read(fd, buf->str, buf->allocated_len);
		if (len < 0)
			g_critical("Read failed: %s", g_strerror(errno));
		if (len == 0 && !push_scan_data)
			/* End of file or stream. */
			break;
		push_scan_data = FALSE;
		buf->len = len;
		if (sr_input_send(in, buf) != SR_OK) {
			g_critical("File import failed (read)");
			break;
		}

		sdi = sr_input_dev_inst_get(in);
		if (!got_sdi && sdi) {
			/* First time we got a valid sdi. */
			if (select_channels(sdi) != SR_OK) {
				g_critical("File import failed (channels)");
				return;
			}
			if (sr_session_dev_add(session, sdi) != SR_OK) {
				g_critical("Failed to use device.");
				sr_session_destroy(session);
				return;
			}
			got_sdi = TRUE;
		}
	}
	sr_input_end(in);
	sr_input_free(in);
	g_string_free(buf, TRUE);
	close(fd);

	df_arg->session = NULL;
	sr_session_destroy(session);
}

void load_input_file(gboolean do_props)
{
	struct df_arg_desc df_arg;
	struct sr_session *session;
	struct sr_dev_inst *sdi;
	GSList *devices;
	GMainLoop *main_loop;
	int ret;

	memset(&df_arg, 0, sizeof(df_arg));
	df_arg.do_props = do_props;

	if (!strcmp(opt_input_file, "-")) {
		/* Input from stdin is never a session file. */
		load_input_file_module(&df_arg);
	} else {
		if ((ret = sr_session_load(sr_ctx, opt_input_file,
				&session)) == SR_OK) {
			/* sigrok session file */
			ret = sr_session_dev_list(session, &devices);
			if (ret != SR_OK || !devices || !devices->data) {
				g_critical("Failed to access session device.");
				g_slist_free(devices);
				sr_session_destroy(session);
				return;
			}
			sdi = devices->data;
			g_slist_free(devices);
			if (select_channels(sdi) != SR_OK) {
				sr_session_destroy(session);
				return;
			}
			main_loop = g_main_loop_new(NULL, FALSE);

			df_arg.session = session;
			sr_session_datafeed_callback_add(session,
				datafeed_in, &df_arg);
			sr_session_stopped_callback_set(session,
				(sr_session_stopped_callback)g_main_loop_quit,
				main_loop);
			if (sr_session_start(session) == SR_OK)
				g_main_loop_run(main_loop);

			g_main_loop_unref(main_loop);
			df_arg.session = NULL;
			sr_session_destroy(session);
		} else if (ret != SR_ERR) {
			/* It's a session file, but it didn't work out somehow. */
			g_critical("Failed to load session file.");
		} else {
			/* Fall back on input modules. */
			load_input_file_module(&df_arg);
		}
	}
}