[libsigrok.git] / src / resource.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2015 Daniel Elstner <daniel.kitta@gmail.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 <errno.h>
#include <stdio.h>
#include <glib.h>
#include <glib/gstdio.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"

/** @cond PRIVATE */
#define LOG_PREFIX "resource"
/** @endcond */

/**
 * @file
 *
 * Access to resource files.
 */

/** Retrieve the size of the open stream @a file.
 *
 * This function only works on seekable streams. However, the set of seekable
 * streams is generally congruent with the set of streams that have a size.
 * Code that needs to work with any type of stream (including pipes) should
 * require neither seekability nor advance knowledge of the size.
 * On failure, the return value is negative and errno is set.
 *
 * @param file An I/O stream opened in binary mode.
 * @return The size of @a file in bytes, or a negative value on failure.
 *
 * @private
 */
SR_PRIV int64_t sr_file_get_size(FILE *file)
{
	off_t filepos, filesize;

	/* ftello() and fseeko() are not standard C, but part of POSIX.1-2001.
	 * Thus, if these functions are available at all, they can reasonably
	 * be expected to also conform to POSIX semantics. In particular, this
	 * means that ftello() after fseeko(..., SEEK_END) has a defined result
	 * and can be used to get the size of a seekable stream.
	 * On Windows, the result is fully defined only for binary streams.
	 */
	filepos = ftello(file);
	if (filepos < 0)
		return -1;

	if (fseeko(file, 0, SEEK_END) < 0)
		return -1;

	filesize = ftello(file);
	if (filesize < 0)
		return -1;

	if (fseeko(file, filepos, SEEK_SET) < 0)
		return -1;

	return filesize;
}

static FILE *try_open_file(const char *datadir, const char *subdir,
		const char *name)
{
	char *filename;
	FILE *file;

	filename = g_build_filename(datadir, subdir, name, NULL);
	file = g_fopen(filename, "rb");

	if (file)
		sr_info("Opened '%s'.", filename);
	else
		sr_spew("Attempt to open '%s' failed: %s",
			filename, g_strerror(errno));
	g_free(filename);

	return file;
}

static int resource_open_default(struct sr_resource *res,
		const char *name, void *cb_data)
{
	int64_t filesize;
	const char *builtindir, *subdir;
	const char *const *datadirs;
	FILE *file;

	(void)cb_data;

	switch (res->type) {
	case SR_RESOURCE_FIRMWARE:
		builtindir = FIRMWARE_DIR;
		subdir = "sigrok-firmware";
		break;
	default:
		sr_err("%s: unknown type %d.", __func__, res->type);
		return SR_ERR_ARG;
	}

	file = try_open_file(g_get_user_data_dir(), subdir, name);
	/*
	 * Scan the hard-coded directory before the system directories to
	 * avoid picking up possibly outdated files from a system install.
	 */
	if (!file)
		file = try_open_file(builtindir, "", name);

	if (!file) {
		datadirs = g_get_system_data_dirs();
		while (*datadirs && !file)
			file = try_open_file(*datadirs++, subdir, name);
	}
	if (!file) {
		sr_err("Failed to locate '%s'.", name);
		return SR_ERR;
	}

	filesize = sr_file_get_size(file);
	if (filesize < 0) {
		sr_err("Failed to obtain size of '%s': %s",
			name, g_strerror(errno));
		fclose(file);
		return SR_ERR;
	}
	res->size = filesize;
	res->handle = file;

	return SR_OK;
}

static int resource_close_default(struct sr_resource *res, void *cb_data)
{
	FILE *file;

	(void)cb_data;

	file = res->handle;
	if (!file) {
		sr_err("%s: invalid handle.", __func__);
		return SR_ERR_ARG;
	}

	if (fclose(file) < 0) {
		sr_err("Failed to close file: %s", g_strerror(errno));
		return SR_ERR;
	}
	res->handle = NULL;

	return SR_OK;
}

static ssize_t resource_read_default(const struct sr_resource *res,
		void *buf, size_t count, void *cb_data)
{
	FILE *file;
	size_t n_read;

	(void)cb_data;

	file = res->handle;
	if (!file) {
		sr_err("%s: invalid handle.", __func__);
		return SR_ERR_ARG;
	}
	if (count > SSIZE_MAX) {
		sr_err("%s: count %zu too large.", __func__, count);
		return SR_ERR_ARG;
	}

	n_read = fread(buf, 1, count, file);

	if (n_read != count && ferror(file)) {
		sr_err("Failed to read resource file: %s", g_strerror(errno));
		return SR_ERR;
	}
	return n_read;
}

/**
 * Install resource access hooks.
 *
 * @param ctx libsigrok context. Must not be NULL.
 * @param open_cb Resource open callback, or NULL to unset.
 * @param close_cb Resource close callback, or NULL to unset.
 * @param read_cb Resource read callback, or NULL to unset.
 * @param cb_data User data pointer passed to callbacks.
 *
 * @retval SR_OK Success.
 * @retval SR_ERR_ARG Invalid argument.
 *
 * @since 0.4.0
 */
SR_API int sr_resource_set_hooks(struct sr_context *ctx,
		sr_resource_open_callback open_cb,
		sr_resource_close_callback close_cb,
		sr_resource_read_callback read_cb, void *cb_data)
{
	if (!ctx) {
		sr_err("%s: ctx was NULL.", __func__);
		return SR_ERR_ARG;
	}
	if (open_cb && close_cb && read_cb) {
		ctx->resource_open_cb  = open_cb;
		ctx->resource_close_cb = close_cb;
		ctx->resource_read_cb  = read_cb;
		ctx->resource_cb_data  = cb_data;
	} else if (!open_cb && !close_cb && !read_cb) {
		ctx->resource_open_cb  = &resource_open_default;
		ctx->resource_close_cb = &resource_close_default;
		ctx->resource_read_cb  = &resource_read_default;
		ctx->resource_cb_data  = ctx;
	} else {
		sr_err("%s: inconsistent callback pointers.", __func__);
		return SR_ERR_ARG;
	}
	return SR_OK;
}

/**
 * Open resource.
 *
 * @param ctx libsigrok context. Must not be NULL.
 * @param[out] res Resource descriptor to fill in. Must not be NULL.
 * @param type Resource type ID.
 * @param name Name of the resource. Must not be NULL.
 *
 * @retval SR_OK Success.
 * @retval SR_ERR_ARG Invalid argument.
 * @retval SR_ERR Other error.
 *
 * @private
 */
SR_PRIV int sr_resource_open(struct sr_context *ctx,
		struct sr_resource *res, int type, const char *name)
{
	int ret;

	res->size = 0;
	res->handle = NULL;
	res->type = type;

	ret = (*ctx->resource_open_cb)(res, name, ctx->resource_cb_data);

	if (ret != SR_OK)
		sr_err("Failed to open resource '%s'.", name);

	return ret;
}

/**
 * Close resource.
 *
 * @param ctx libsigrok context. Must not be NULL.
 * @param[inout] res Resource descriptor. Must not be NULL.
 *
 * @retval SR_OK Success.
 * @retval SR_ERR_ARG Invalid argument.
 * @retval SR_ERR Other error.
 *
 * @private
 */
SR_PRIV int sr_resource_close(struct sr_context *ctx, struct sr_resource *res)
{
	int ret;

	ret = (*ctx->resource_close_cb)(res, ctx->resource_cb_data);

	if (ret != SR_OK)
		sr_err("Failed to close resource.");

	return ret;
}

/**
 * Read resource data.
 *
 * @param ctx libsigrok context. Must not be NULL.
 * @param[in] res Resource descriptor. Must not be NULL.
 * @param[out] buf Buffer to store @a count bytes into. Must not be NULL.
 * @param count Number of bytes to read.
 *
 * @return The number of bytes actually read, or a negative value on error.
 * @retval SR_ERR_ARG Invalid argument.
 * @retval SR_ERR Other error.
 *
 * @private
 */
SR_PRIV ssize_t sr_resource_read(struct sr_context *ctx,
		const struct sr_resource *res, void *buf, size_t count)
{
	ssize_t n_read;

	n_read = (*ctx->resource_read_cb)(res, buf, count,
			ctx->resource_cb_data);
	if (n_read < 0)
		sr_err("Failed to read resource.");

	return n_read;
}

/**
 * Load a resource into memory.
 *
 * @param ctx libsigrok context. Must not be NULL.
 * @param type Resource type ID.
 * @param name Name of the resource. Must not be NULL.
 * @param[out] size Size in bytes of the returned buffer. Must not be NULL.
 * @param max_size Size limit. Error out if the resource is larger than this.
 *
 * @return A buffer containing the resource data, or NULL on failure. Must
 *  be freed by the caller using g_free().
 *
 * @private
 */
SR_PRIV void *sr_resource_load(struct sr_context *ctx,
		int type, const char *name, size_t *size, size_t max_size)
{
	struct sr_resource res;
	void *buf;
	ssize_t n_read;

	if (sr_resource_open(ctx, &res, type, name) != SR_OK)
		return NULL;

	if (res.size > max_size) {
		sr_err("Size %" PRIu64 " of '%s' exceeds limit %zu.",
			res.size, name, max_size);
		sr_resource_close(ctx, &res);
		return NULL;
	}
	buf = g_try_malloc(res.size);
	if (!buf) {
		sr_err("Failed to allocate buffer for '%s'.", name);
		sr_resource_close(ctx, &res);
		return NULL;
	}

	n_read = sr_resource_read(ctx, &res, buf, res.size);
	sr_resource_close(ctx, &res);

	if (n_read < 0 || (size_t)n_read != res.size) {
		if (n_read >= 0)
			sr_err("Failed to read '%s': premature end of file.",
				name);
		g_free(buf);
		return NULL;
	}

	*size = res.size;
	return buf;
}

/** @} */
Commit	Line	Data
bee24666 DE	1	/*
	2	* This file is part of the libsigrok project.
	3	*
	4	* Copyright (C) 2015 Daniel Elstner <daniel.kitta@gmail.com>
	5	*
	6	* This program is free software: you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation, either version 3 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	18	*/
	19
	20	#include <config.h>
	21	#include <errno.h>
	22	#include <stdio.h>
	23	#include <glib.h>
	24	#include <glib/gstdio.h>
	25	#include <libsigrok/libsigrok.h>
	26	#include "libsigrok-internal.h"
	27
	28	/** @cond PRIVATE */
	29	#define LOG_PREFIX "resource"
	30	/** @endcond */
	31
	32	/**
	33	* @file
	34	*
	35	* Access to resource files.
	36	*/
	37
7d89fd60 DE	38	/** Retrieve the size of the open stream @a file.
	39	*
	40	* This function only works on seekable streams. However, the set of seekable
	41	* streams is generally congruent with the set of streams that have a size.
	42	* Code that needs to work with any type of stream (including pipes) should
	43	* require neither seekability nor advance knowledge of the size.
	44	* On failure, the return value is negative and errno is set.
	45	*
	46	* @param file An I/O stream opened in binary mode.
	47	* @return The size of @a file in bytes, or a negative value on failure.
	48	*
	49	* @private
	50	*/
	51	SR_PRIV int64_t sr_file_get_size(FILE *file)
	52	{
	53	off_t filepos, filesize;
	54
	55	/* ftello() and fseeko() are not standard C, but part of POSIX.1-2001.
	56	* Thus, if these functions are available at all, they can reasonably
	57	* be expected to also conform to POSIX semantics. In particular, this
	58	* means that ftello() after fseeko(..., SEEK_END) has a defined result
	59	* and can be used to get the size of a seekable stream.
	60	* On Windows, the result is fully defined only for binary streams.
	61	*/
	62	filepos = ftello(file);
	63	if (filepos < 0)
	64	return -1;
	65
	66	if (fseeko(file, 0, SEEK_END) < 0)
	67	return -1;
	68
	69	filesize = ftello(file);
	70	if (filesize < 0)
	71	return -1;
	72
	73	if (fseeko(file, filepos, SEEK_SET) < 0)
	74	return -1;
	75
	76	return filesize;
	77	}
	78
bee24666 DE	79	static FILE try_open_file(const char datadir, const char *subdir,
	80	const char *name)
	81	{
	82	char *filename;
	83	FILE *file;
	84
	85	filename = g_build_filename(datadir, subdir, name, NULL);
	86	file = g_fopen(filename, "rb");
	87
	88	if (file)
	89	sr_info("Opened '%s'.", filename);
	90	else
	91	sr_spew("Attempt to open '%s' failed: %s",
	92	filename, g_strerror(errno));
	93	g_free(filename);
	94
	95	return file;
	96	}
	97
	98	static int resource_open_default(struct sr_resource *res,
	99	const char name, void cb_data)
	100	{
	101	int64_t filesize;
	102	const char builtindir, subdir;
	103	const char const datadirs;
	104	FILE *file;
	105
	106	(void)cb_data;
	107
	108	switch (res->type) {
	109	case SR_RESOURCE_FIRMWARE:
	110	builtindir = FIRMWARE_DIR;
	111	subdir = "sigrok-firmware";
	112	break;
	113	default:
	114	sr_err("%s: unknown type %d.", __func__, res->type);
	115	return SR_ERR_ARG;
	116	}
	117
	118	file = try_open_file(g_get_user_data_dir(), subdir, name);
	119	/*
	120	* Scan the hard-coded directory before the system directories to
	121	* avoid picking up possibly outdated files from a system install.
	122	*/
	123	if (!file)
	124	file = try_open_file(builtindir, "", name);
	125
	126	if (!file) {
	127	datadirs = g_get_system_data_dirs();
	128	while (*datadirs && !file)
	129	file = try_open_file(*datadirs++, subdir, name);
	130	}
	131	if (!file) {
	132	sr_err("Failed to locate '%s'.", name);
	133	return SR_ERR;
	134	}
	135
	136	filesize = sr_file_get_size(file);
	137	if (filesize < 0) {
	138	sr_err("Failed to obtain size of '%s': %s",
	139	name, g_strerror(errno));
	140	fclose(file);
	141	return SR_ERR;
	142	}
143	res->size = filesize;
144	res->handle = file;
145
146	return SR_OK;
147	}
148
149	static int resource_close_default(struct sr_resource res, void cb_data)
150	{
151	FILE *file;
152
153	(void)cb_data;
154
155	file = res->handle;
156	if (!file) {
157	sr_err("%s: invalid handle.", __func__);
158	return SR_ERR_ARG;
159	}
160
161	if (fclose(file) < 0) {
162	sr_err("Failed to close file: %s", g_strerror(errno));
163	return SR_ERR;
164	}
165	res->handle = NULL;
166
167	return SR_OK;
168	}
169
170	static ssize_t resource_read_default(const struct sr_resource *res,
171	void buf, size_t count, void cb_data)
172	{
173	FILE *file;
174	size_t n_read;
175
176	(void)cb_data;
177
178	file = res->handle;
179	if (!file) {
180	sr_err("%s: invalid handle.", __func__);
181	return SR_ERR_ARG;
182	}
183	if (count > SSIZE_MAX) {
184	sr_err("%s: count %zu too large.", __func__, count);
185	return SR_ERR_ARG;
186	}
187
188	n_read = fread(buf, 1, count, file);
189
190	if (n_read != count && ferror(file)) {
191	sr_err("Failed to read resource file: %s", g_strerror(errno));
192	return SR_ERR;
193	}
194	return n_read;
195	}
196
197	/**
198	* Install resource access hooks.
199	*
200	* @param ctx libsigrok context. Must not be NULL.
201	* @param open_cb Resource open callback, or NULL to unset.
202	* @param close_cb Resource close callback, or NULL to unset.
203	* @param read_cb Resource read callback, or NULL to unset.
204	* @param cb_data User data pointer passed to callbacks.
205	*
206	* @retval SR_OK Success.
207	* @retval SR_ERR_ARG Invalid argument.
208	*
209	* @since 0.4.0
210	*/
211	SR_API int sr_resource_set_hooks(struct sr_context *ctx,
212	sr_resource_open_callback open_cb,
213	sr_resource_close_callback close_cb,
214	sr_resource_read_callback read_cb, void *cb_data)
215	{
216	if (!ctx) {
217	sr_err("%s: ctx was NULL.", __func__);
218	return SR_ERR_ARG;
219	}
220	if (open_cb && close_cb && read_cb) {
221	ctx->resource_open_cb = open_cb;
222	ctx->resource_close_cb = close_cb;
223	ctx->resource_read_cb = read_cb;
224	ctx->resource_cb_data = cb_data;
225	} else if (!open_cb && !close_cb && !read_cb) {
226	ctx->resource_open_cb = &resource_open_default;
227	ctx->resource_close_cb = &resource_close_default;
228	ctx->resource_read_cb = &resource_read_default;
229	ctx->resource_cb_data = ctx;
230	} else {
231	sr_err("%s: inconsistent callback pointers.", __func__);
232	return SR_ERR_ARG;
233	}
234	return SR_OK;
235	}
236
237	/**
238	* Open resource.
239	*
240	* @param ctx libsigrok context. Must not be NULL.
241	* @param[out] res Resource descriptor to fill in. Must not be NULL.
242	* @param type Resource type ID.
243	* @param name Name of the resource. Must not be NULL.
244	*
245	* @retval SR_OK Success.
246	* @retval SR_ERR_ARG Invalid argument.
247	* @retval SR_ERR Other error.
248	*
249	* @private
250	*/
251	SR_PRIV int sr_resource_open(struct sr_context *ctx,
252	struct sr_resource res, int type, const char name)
253	{
254	int ret;
255
256	res->size = 0;
257	res->handle = NULL;
258	res->type = type;
259
260	ret = (*ctx->resource_open_cb)(res, name, ctx->resource_cb_data);
261
262	if (ret != SR_OK)
263	sr_err("Failed to open resource '%s'.", name);
264
265	return ret;
266	}
267
268	/**
269	* Close resource.
270	*
271	* @param ctx libsigrok context. Must not be NULL.
272	* @param[inout] res Resource descriptor. Must not be NULL.
273	*
274	* @retval SR_OK Success.
275	* @retval SR_ERR_ARG Invalid argument.
276	* @retval SR_ERR Other error.
277	*
278	* @private
279	*/
280	SR_PRIV int sr_resource_close(struct sr_context ctx, struct sr_resource res)
281	{
282	int ret;
283
284	ret = (*ctx->resource_close_cb)(res, ctx->resource_cb_data);
285
286	if (ret != SR_OK)
287	sr_err("Failed to close resource.");
288
289	return ret;
290	}
291
292	/**
293	* Read resource data.
294	*
295	* @param ctx libsigrok context. Must not be NULL.
296	* @param[in] res Resource descriptor. Must not be NULL.
297	* @param[out] buf Buffer to store @a count bytes into. Must not be NULL.
298	* @param count Number of bytes to read.
299	*
300	* @return The number of bytes actually read, or a negative value on error.
301	* @retval SR_ERR_ARG Invalid argument.
302	* @retval SR_ERR Other error.
303	*
304	* @private
305	*/
306	SR_PRIV ssize_t sr_resource_read(struct sr_context *ctx,
307	const struct sr_resource res, void buf, size_t count)
308	{
309	ssize_t n_read;
310
311	n_read = (*ctx->resource_read_cb)(res, buf, count,
312	ctx->resource_cb_data);
313	if (n_read < 0)
314	sr_err("Failed to read resource.");
315
316	return n_read;
317	}
318
319	/**
320	* Load a resource into memory.
321	*
322	* @param ctx libsigrok context. Must not be NULL.
323	* @param type Resource type ID.
324	* @param name Name of the resource. Must not be NULL.
325	* @param[out] size Size in bytes of the returned buffer. Must not be NULL.
326	* @param max_size Size limit. Error out if the resource is larger than this.
327	*
328	* @return A buffer containing the resource data, or NULL on failure. Must
329	* be freed by the caller using g_free().
330	*
331	* @private
332	*/
333	SR_PRIV void sr_resource_load(struct sr_context ctx,
334	int type, const char name, size_t size, size_t max_size)
335	{
336	struct sr_resource res;
337	void *buf;
338	ssize_t n_read;
339
340	if (sr_resource_open(ctx, &res, type, name) != SR_OK)
341	return NULL;
342
343	if (res.size > max_size) {
344	sr_err("Size %" PRIu64 " of '%s' exceeds limit %zu.",
345	res.size, name, max_size);
346	sr_resource_close(ctx, &res);
347	return NULL;
348	}
349	buf = g_try_malloc(res.size);
350	if (!buf) {
351	sr_err("Failed to allocate buffer for '%s'.", name);
352	sr_resource_close(ctx, &res);
353	return NULL;
354	}
355
356	n_read = sr_resource_read(ctx, &res, buf, res.size);
357	sr_resource_close(ctx, &res);
358
359	if (n_read < 0 \|\| (size_t)n_read != res.size) {
360	if (n_read >= 0)
361	sr_err("Failed to read '%s': premature end of file.",
362	name);
363	g_free(buf);
364	return NULL;
365	}
366
367	*size = res.size;
368	return buf;
369	}
370
371	/** @} */