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/*

 * Copyright 2008 Rob Kendrick 

 *

 * This file is part of NetSurf.

 *

 * NetSurf 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; version 2 of the License.

 *

 * NetSurf 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 .

 */

/* data: URL handling.  See http://tools.ietf.org/html/rfc2397 */

#include 

#include 

#include 

#include 

#include 

#include 

#include 		/* for URL unescaping functions */

#include 

#include "utils/config.h"

#include "content/fetch.h"

#include "content/fetchers/data.h"

#include "content/urldb.h"

#include "desktop/netsurf.h"

#include "desktop/options.h"

#include "utils/log.h"

#include "utils/messages.h"

#include "utils/url.h"

#include "utils/utils.h"

#include "utils/ring.h"

#include "utils/base64.h"

struct fetch_data_context {

	struct fetch *parent_fetch;

	char *url;

	char *mimetype;

	char *data;

	size_t datalen;

	bool base64;

	bool aborted;

	bool locked;

	struct fetch_data_context *r_next, *r_prev;

};

static struct fetch_data_context *ring = NULL;

static CURL *curl;

static bool fetch_data_initialise(lwc_string *scheme)

{

	LOG(("fetch_data_initialise called for %s", lwc_string_data(scheme)));

	if ( (curl = curl_easy_init()) == NULL)

		return false;

	else

		return true;

}

static void fetch_data_finalise(lwc_string *scheme)

{

	LOG(("fetch_data_finalise called for %s", lwc_string_data(scheme)));

	curl_easy_cleanup(curl);

}

static bool fetch_data_can_fetch(const nsurl *url)

{

	return true;

}

static void *fetch_data_setup(struct fetch *parent_fetch, nsurl *url,

		 bool only_2xx, bool downgrade_tls, const char *post_urlenc,

		 const struct fetch_multipart_data *post_multipart,

		 const char **headers)

{

	struct fetch_data_context *ctx = calloc(1, sizeof(*ctx));

	if (ctx == NULL)

		return NULL;

	ctx->parent_fetch = parent_fetch;

	/* TODO: keep as nsurl to avoid copy */

	ctx->url = malloc(nsurl_length(url) + 1);

	if (ctx->url == NULL) {

		free(ctx);

		return NULL;

	}

	memcpy(ctx->url, nsurl_access(url), nsurl_length(url) + 1);

	RING_INSERT(ring, ctx);

	return ctx;

}

static bool fetch_data_start(void *ctx)

{

	return true;

}

static void fetch_data_free(void *ctx)

{

	struct fetch_data_context *c = ctx;

	free(c->url);

	free(c->data);

	free(c->mimetype);

	RING_REMOVE(ring, c);

	free(ctx);

}

static void fetch_data_abort(void *ctx)

{

	struct fetch_data_context *c = ctx;

	/* To avoid the poll loop having to deal with the fetch context

	 * disappearing from under it, we simply flag the abort here.

	 * The poll loop itself will perform the appropriate cleanup.

	 */

	c->aborted = true;

}

static void fetch_data_send_callback(const fetch_msg *msg,

		struct fetch_data_context *c)

{

	c->locked = true;

	fetch_send_callback(msg, c->parent_fetch);

	c->locked = false;

}

static bool fetch_data_process(struct fetch_data_context *c)

{

	fetch_msg msg;

	char *params;

	char *comma;

	char *unescaped;

        int templen;

	/* format of a data: URL is:

	 *   data:[][;base64],

	 * The mimetype is optional.  If it is missing, the , before the

	 * data must still be there.

	 */

	LOG(("url: %.140s", c->url));

	if (strlen(c->url) < 6) {

		/* 6 is the minimum possible length (data:,) */

		msg.type = FETCH_ERROR;

		msg.data.error = "Malformed data: URL";

		fetch_data_send_callback(&msg, c);

		return false;

	}

	/* skip the data: part */

	params = c->url + SLEN("data:");

	/* find the comma */

	if ( (comma = strchr(params, ',')) == NULL) {

		msg.type = FETCH_ERROR;

		msg.data.error = "Malformed data: URL";

		fetch_data_send_callback(&msg, c);

		return false;

	}

	if (params[0] == ',') {

		/* there is no mimetype here, assume text/plain */

		c->mimetype = strdup("text/plain;charset=US-ASCII");

	} else {

		/* make a copy of everything between data: and the comma */

		c->mimetype = strndup(params, comma - params);

	}

	if (c->mimetype == NULL) {

		msg.type = FETCH_ERROR;

		msg.data.error =

			"Unable to allocate memory for mimetype in data: URL";

		fetch_data_send_callback(&msg, c);

		return false;

	}

	if (strcmp(c->mimetype + strlen(c->mimetype) - 7, ";base64") == 0) {

		c->base64 = true;

		c->mimetype[strlen(c->mimetype) - 7] = '\0';

	} else {

		c->base64 = false;

	}

	/* we URL unescape the data first, just incase some insane page

	 * decides to nest URL and base64 encoding.  Like, say, Acid2.

	 */

        templen = c->datalen;

        unescaped = curl_easy_unescape(curl, comma + 1, 0, &templen);

        c->datalen = templen;

        if (unescaped == NULL) {

		msg.type = FETCH_ERROR;

		msg.data.error = "Unable to URL decode data: URL";

		fetch_data_send_callback(&msg, c);

		return false;

	}

	if (c->base64) {

		c->data = malloc(c->datalen); /* safe: always gets smaller */

		if (base64_decode(unescaped, c->datalen, c->data,

				&(c->datalen)) == false) {

			msg.type = FETCH_ERROR;

			msg.data.error = "Unable to Base64 decode data: URL";

			fetch_data_send_callback(&msg, c);

			curl_free(unescaped);

			return false;

		}

	} else {

		c->data = malloc(c->datalen);

		if (c->data == NULL) {

			msg.type = FETCH_ERROR;

			msg.data.error =

				"Unable to allocate memory for data: URL";

			fetch_data_send_callback(&msg, c);

			curl_free(unescaped);

			return false;

		}

		memcpy(c->data, unescaped, c->datalen);

	}

	curl_free(unescaped);

	return true;

}

static void fetch_data_poll(lwc_string *scheme)

{

	fetch_msg msg;

	struct fetch_data_context *c, *next;

	if (ring == NULL) return;

	/* Iterate over ring, processing each pending fetch */

	c = ring;

	do {

		/* Ignore fetches that have been flagged as locked.

		 * This allows safe re-entrant calls to this function.

		 * Re-entrancy can occur if, as a result of a callback,

		 * the interested party causes fetch_poll() to be called

		 * again.

		 */

		if (c->locked == true) {

			next = c->r_next;

			continue;

		}

		/* Only process non-aborted fetches */

		if (c->aborted == false && fetch_data_process(c) == true) {

			char header[64];

			fetch_set_http_code(c->parent_fetch, 200);

			LOG(("setting data: MIME type to %s, length to %zd",

					c->mimetype, c->datalen));

			/* Any callback can result in the fetch being aborted.

			 * Therefore, we _must_ check for this after _every_

			 * call to fetch_data_send_callback().

			 */

			snprintf(header, sizeof header, "Content-Type: %s",

					c->mimetype);

			msg.type = FETCH_HEADER;

			msg.data.header_or_data.buf = (const uint8_t *) header;

			msg.data.header_or_data.len = strlen(header);

			fetch_data_send_callback(&msg, c);

			if (c->aborted == false) {

				snprintf(header, sizeof header,

					"Content-Length: %"SSIZET_FMT,

					c->datalen);

				msg.type = FETCH_HEADER;

				msg.data.header_or_data.buf =

						(const uint8_t *) header;

				msg.data.header_or_data.len = strlen(header);

				fetch_data_send_callback(&msg, c);

			}

			if (c->aborted == false) {

				msg.type = FETCH_DATA;

				msg.data.header_or_data.buf =

						(const uint8_t *) c->data;

				msg.data.header_or_data.len = c->datalen;

				fetch_data_send_callback(&msg, c);

			}

			if (c->aborted == false) {

				msg.type = FETCH_FINISHED;

				fetch_data_send_callback(&msg, c);

			}

		} else {

			LOG(("Processing of %s failed!", c->url));

			/* Ensure that we're unlocked here. If we aren't,

			 * then fetch_data_process() is broken.

			 */

			assert(c->locked == false);

		}

		/* Compute next fetch item at the last possible moment as

		 * processing this item may have added to the ring.

		 */

		next = c->r_next;

		fetch_remove_from_queues(c->parent_fetch);

		fetch_free(c->parent_fetch);

		/* Advance to next ring entry, exiting if we've reached

		 * the start of the ring or the ring has become empty

		 */

	} while ( (c = next) != ring && ring != NULL);

}

void fetch_data_register(void)

{

	lwc_string *scheme;

	if (lwc_intern_string("data", SLEN("data"), &scheme) != lwc_error_ok) {

		die("Failed to initialise the fetch module "

				"(couldn't intern \"data\").");

	}

	fetch_add_fetcher(scheme,

		fetch_data_initialise,

		fetch_data_can_fetch,

		fetch_data_setup,

		fetch_data_start,

		fetch_data_abort,

		fetch_data_free,

		fetch_data_poll,

		fetch_data_finalise);

}