[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.
 */

/**
 * Get a list of paths where we look for resource (e.g. firmware) files.
 *
 * @param res_type The type of resource to get the search paths for.
 *
 * @return List of strings that must be freed after use, including the strings.
 *
 * @since 0.6.0
 */
SR_API GSList *sr_resourcepaths_get(int res_type)
{
	const char *subdir = NULL;
	GSList *l = NULL;
	const char *env;
	const char *const *datadirs;

	if (res_type == SR_RESOURCE_FIRMWARE) {
		subdir = "sigrok-firmware";

		env = g_getenv("SIGROK_FIRMWARE_DIR");
		if (env)
			l = g_slist_append(l, g_strdup(env));

		env = g_getenv("SIGROK_FIRMWARE_PATH");
		if (env) {
			char **dir_list, **dir_iter, *dir_item;
			dir_list = g_strsplit(env, G_SEARCHPATH_SEPARATOR_S, 0);
			for (dir_iter = dir_list; *dir_iter; dir_iter++) {
				dir_item = *dir_iter;
				if (!dir_item || !*dir_item)
					continue;
				l = g_slist_append(l, g_strdup(dir_item));
			}
			g_strfreev(dir_list);
		}
	}

	l = g_slist_append(l, g_build_filename(g_get_user_data_dir(), subdir, NULL));

#ifdef FIRMWARE_DIR
	if (res_type == SR_RESOURCE_FIRMWARE) {
		/*
		 * Scan the hard-coded directory before the system directories to
		 * avoid picking up possibly outdated files from a system install.
		 */
		l = g_slist_append(l, g_strdup(FIRMWARE_DIR));
	}
#endif

	datadirs = g_get_system_data_dirs();
	while (*datadirs)
		l = g_slist_append(l, g_build_filename(*datadirs++, subdir, NULL));

	return l;
}

/**
 * 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;

	if (subdir)
		filename = g_build_filename(datadir, subdir, name, NULL);
	else
		filename = g_build_filename(datadir, 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)
{
	GSList *paths, *p = NULL;
	int64_t filesize;
	FILE *file = NULL;

	(void)cb_data;

	paths = sr_resourcepaths_get(res->type);

	/* Currently, the enum only defines SR_RESOURCE_FIRMWARE. */
	if (res->type != SR_RESOURCE_FIRMWARE) {
		sr_err("%s: unknown type %d.", __func__, res->type);
		return SR_ERR_ARG;
	}

	p = paths;
	while (p && !file) {
		file = try_open_file((const char *)(p->data), NULL, name);
		p = p->next;
	}
	g_slist_free_full(paths, g_free);

	if (!file) {
		sr_dbg("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 gssize 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 > G_MAXSSIZE) {
		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' (use loglevel 5/spew for"
		       " details).", 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 gssize sr_resource_read(struct sr_context *ctx,
		const struct sr_resource *res, void *buf, size_t count)
{
	gssize 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;
	size_t res_size;
	gssize 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;
	}
	res_size = res.size;

	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
addb7340 SA	38	/**
	39	* Get a list of paths where we look for resource (e.g. firmware) files.
	40	*
	41	* @param res_type The type of resource to get the search paths for.
	42	*
	43	* @return List of strings that must be freed after use, including the strings.
	44	*
	45	* @since 0.6.0
	46	*/
	47	SR_API GSList *sr_resourcepaths_get(int res_type)
	48	{
	49	const char *subdir = NULL;
	50	GSList *l = NULL;
	51	const char *env;
	52	const char const datadirs;
	53
	54	if (res_type == SR_RESOURCE_FIRMWARE) {
	55	subdir = "sigrok-firmware";
	56
	57	env = g_getenv("SIGROK_FIRMWARE_DIR");
3ad0308c	58	if (env)
addb7340	59	l = g_slist_append(l, g_strdup(env));
4a57cc35 GS	60
	61	env = g_getenv("SIGROK_FIRMWARE_PATH");
	62	if (env) {
	63	char dir_list, dir_iter, *dir_item;
	64	dir_list = g_strsplit(env, G_SEARCHPATH_SEPARATOR_S, 0);
	65	for (dir_iter = dir_list; *dir_iter; dir_iter++) {
	66	dir_item = *dir_iter;
	67	if (!dir_item \|\| !*dir_item)
	68	continue;
	69	l = g_slist_append(l, g_strdup(dir_item));
	70	}
	71	g_strfreev(dir_list);
	72	}
addb7340 SA	73	}
	74
	75	l = g_slist_append(l, g_build_filename(g_get_user_data_dir(), subdir, NULL));
	76
	77	#ifdef FIRMWARE_DIR
	78	if (res_type == SR_RESOURCE_FIRMWARE) {
	79	/*
	80	* Scan the hard-coded directory before the system directories to
	81	* avoid picking up possibly outdated files from a system install.
	82	*/
	83	l = g_slist_append(l, g_strdup(FIRMWARE_DIR));
	84	}
	85	#endif
	86
	87	datadirs = g_get_system_data_dirs();
	88	while (*datadirs)
	89	l = g_slist_append(l, g_build_filename(*datadirs++, subdir, NULL));
	90
	91	return l;
	92	}
	93
	94	/**
	95	* Retrieve the size of the open stream @a file.
7d89fd60 DE	96	*
	97	* This function only works on seekable streams. However, the set of seekable
	98	* streams is generally congruent with the set of streams that have a size.
	99	* Code that needs to work with any type of stream (including pipes) should
	100	* require neither seekability nor advance knowledge of the size.
	101	* On failure, the return value is negative and errno is set.
	102	*
	103	* @param file An I/O stream opened in binary mode.
	104	* @return The size of @a file in bytes, or a negative value on failure.
	105	*
	106	* @private
	107	*/
	108	SR_PRIV int64_t sr_file_get_size(FILE *file)
	109	{
	110	off_t filepos, filesize;
	111
	112	/* ftello() and fseeko() are not standard C, but part of POSIX.1-2001.
	113	* Thus, if these functions are available at all, they can reasonably
	114	* be expected to also conform to POSIX semantics. In particular, this
	115	* means that ftello() after fseeko(..., SEEK_END) has a defined result
	116	* and can be used to get the size of a seekable stream.
	117	* On Windows, the result is fully defined only for binary streams.
	118	*/
	119	filepos = ftello(file);
	120	if (filepos < 0)
	121	return -1;
	122
	123	if (fseeko(file, 0, SEEK_END) < 0)
	124	return -1;
	125
	126	filesize = ftello(file);
	127	if (filesize < 0)
	128	return -1;
	129
	130	if (fseeko(file, filepos, SEEK_SET) < 0)
	131	return -1;
	132
	133	return filesize;
	134	}
	135
bee24666 DE	136	static FILE try_open_file(const char datadir, const char *subdir,
	137	const char *name)
	138	{
	139	char *filename;
	140	FILE *file;
	141
366ccb8a SA	142	if (subdir)
	143	filename = g_build_filename(datadir, subdir, name, NULL);
	144	else
	145	filename = g_build_filename(datadir, name, NULL);
	146
bee24666 DE	147	file = g_fopen(filename, "rb");
	148
	149	if (file)
	150	sr_info("Opened '%s'.", filename);
	151	else
	152	sr_spew("Attempt to open '%s' failed: %s",
	153	filename, g_strerror(errno));
	154	g_free(filename);
	155
	156	return file;
	157	}
	158
	159	static int resource_open_default(struct sr_resource *res,
	160	const char name, void cb_data)
	161	{
addb7340	162	GSList paths, p = NULL;
bee24666	163	int64_t filesize;
1503d457	164	FILE *file = NULL;
bee24666 DE	165
	166	(void)cb_data;
	167
addb7340 SA	168	paths = sr_resourcepaths_get(res->type);
	169
	170	/* Currently, the enum only defines SR_RESOURCE_FIRMWARE. */
	171	if (res->type != SR_RESOURCE_FIRMWARE) {
bee24666 DE	172	sr_err("%s: unknown type %d.", __func__, res->type);
	173	return SR_ERR_ARG;
	174	}
	175
addb7340 SA	176	p = paths;
	177	while (p && !file) {
	178	file = try_open_file((const char *)(p->data), NULL, name);
	179	p = p->next;
bee24666	180	}
addb7340 SA	181	g_slist_free_full(paths, g_free);
addb7340 SA	182
bee24666	183	if (!file) {
7ade12b4	184	sr_dbg("Failed to locate '%s'.", name);
bee24666 DE	185	return SR_ERR;
	186	}
	187
	188	filesize = sr_file_get_size(file);
	189	if (filesize < 0) {
	190	sr_err("Failed to obtain size of '%s': %s",
	191	name, g_strerror(errno));
	192	fclose(file);
	193	return SR_ERR;
	194	}
	195	res->size = filesize;
	196	res->handle = file;
	197
	198	return SR_OK;
	199	}
	200
	201	static int resource_close_default(struct sr_resource res, void cb_data)
	202	{
	203	FILE *file;
	204
	205	(void)cb_data;
	206
	207	file = res->handle;
	208	if (!file) {
	209	sr_err("%s: invalid handle.", __func__);
	210	return SR_ERR_ARG;
	211	}
	212
	213	if (fclose(file) < 0) {
	214	sr_err("Failed to close file: %s", g_strerror(errno));
	215	return SR_ERR;
	216	}
	217	res->handle = NULL;
	218
	219	return SR_OK;
	220	}
	221
32ba0d80	222	static gssize resource_read_default(const struct sr_resource *res,
bee24666 DE	223	void buf, size_t count, void cb_data)
	224	{
	225	FILE *file;
	226	size_t n_read;
	227
	228	(void)cb_data;
	229
	230	file = res->handle;
	231	if (!file) {
	232	sr_err("%s: invalid handle.", __func__);
	233	return SR_ERR_ARG;
	234	}
32ba0d80	235	if (count > G_MAXSSIZE) {
bee24666 DE	236	sr_err("%s: count %zu too large.", __func__, count);
	237	return SR_ERR_ARG;
	238	}
	239
	240	n_read = fread(buf, 1, count, file);
	241
	242	if (n_read != count && ferror(file)) {
	243	sr_err("Failed to read resource file: %s", g_strerror(errno));
	244	return SR_ERR;
	245	}
	246	return n_read;
	247	}
	248
	249	/**
	250	* Install resource access hooks.
	251	*
	252	* @param ctx libsigrok context. Must not be NULL.
	253	* @param open_cb Resource open callback, or NULL to unset.
	254	* @param close_cb Resource close callback, or NULL to unset.
	255	* @param read_cb Resource read callback, or NULL to unset.
	256	* @param cb_data User data pointer passed to callbacks.
	257	*
	258	* @retval SR_OK Success.
	259	* @retval SR_ERR_ARG Invalid argument.
	260	*
	261	* @since 0.4.0
	262	*/
	263	SR_API int sr_resource_set_hooks(struct sr_context *ctx,
	264	sr_resource_open_callback open_cb,
	265	sr_resource_close_callback close_cb,
	266	sr_resource_read_callback read_cb, void *cb_data)
	267	{
	268	if (!ctx) {
	269	sr_err("%s: ctx was NULL.", __func__);
	270	return SR_ERR_ARG;
	271	}
	272	if (open_cb && close_cb && read_cb) {
d9251a2c	273	ctx->resource_open_cb = open_cb;
bee24666	274	ctx->resource_close_cb = close_cb;
d9251a2c UH	275	ctx->resource_read_cb = read_cb;
d9251a2c UH	276	ctx->resource_cb_data = cb_data;
bee24666	277	} else if (!open_cb && !close_cb && !read_cb) {
d9251a2c	278	ctx->resource_open_cb = &resource_open_default;
bee24666	279	ctx->resource_close_cb = &resource_close_default;
d9251a2c UH	280	ctx->resource_read_cb = &resource_read_default;
d9251a2c UH	281	ctx->resource_cb_data = ctx;
bee24666 DE	282	} else {
	283	sr_err("%s: inconsistent callback pointers.", __func__);
	284	return SR_ERR_ARG;
	285	}
	286	return SR_OK;
	287	}
	288
	289	/**
	290	* Open resource.
	291	*
	292	* @param ctx libsigrok context. Must not be NULL.
	293	* @param[out] res Resource descriptor to fill in. Must not be NULL.
	294	* @param type Resource type ID.
	295	* @param name Name of the resource. Must not be NULL.
	296	*
	297	* @retval SR_OK Success.
	298	* @retval SR_ERR_ARG Invalid argument.
	299	* @retval SR_ERR Other error.
	300	*
	301	* @private
	302	*/
	303	SR_PRIV int sr_resource_open(struct sr_context *ctx,
	304	struct sr_resource res, int type, const char name)
	305	{
	306	int ret;
	307
	308	res->size = 0;
	309	res->handle = NULL;
	310	res->type = type;
	311
	312	ret = (*ctx->resource_open_cb)(res, name, ctx->resource_cb_data);
	313
	314	if (ret != SR_OK)
7ade12b4 UH	315	sr_err("Failed to open resource '%s' (use loglevel 5/spew for"
7ade12b4 UH	316	" details).", name);
bee24666 DE	317
	318	return ret;
	319	}
	320
	321	/**
	322	* Close resource.
	323	*
	324	* @param ctx libsigrok context. Must not be NULL.
	325	* @param[inout] res Resource descriptor. Must not be NULL.
	326	*
	327	* @retval SR_OK Success.
	328	* @retval SR_ERR_ARG Invalid argument.
	329	* @retval SR_ERR Other error.
	330	*
	331	* @private
	332	*/
	333	SR_PRIV int sr_resource_close(struct sr_context ctx, struct sr_resource res)
	334	{
	335	int ret;
	336
	337	ret = (*ctx->resource_close_cb)(res, ctx->resource_cb_data);
	338
	339	if (ret != SR_OK)
	340	sr_err("Failed to close resource.");
	341
	342	return ret;
	343	}
	344
	345	/**
	346	* Read resource data.
	347	*
	348	* @param ctx libsigrok context. Must not be NULL.
	349	* @param[in] res Resource descriptor. Must not be NULL.
	350	* @param[out] buf Buffer to store @a count bytes into. Must not be NULL.
	351	* @param count Number of bytes to read.
	352	*
	353	* @return The number of bytes actually read, or a negative value on error.
	354	* @retval SR_ERR_ARG Invalid argument.
	355	* @retval SR_ERR Other error.
	356	*
	357	* @private
	358	*/
32ba0d80	359	SR_PRIV gssize sr_resource_read(struct sr_context *ctx,
bee24666 DE	360	const struct sr_resource res, void buf, size_t count)
bee24666 DE	361	{
32ba0d80	362	gssize n_read;
bee24666 DE	363
	364	n_read = (*ctx->resource_read_cb)(res, buf, count,
	365	ctx->resource_cb_data);
	366	if (n_read < 0)
	367	sr_err("Failed to read resource.");
	368
	369	return n_read;
	370	}
	371
	372	/**
	373	* Load a resource into memory.
	374	*
	375	* @param ctx libsigrok context. Must not be NULL.
	376	* @param type Resource type ID.
	377	* @param name Name of the resource. Must not be NULL.
	378	* @param[out] size Size in bytes of the returned buffer. Must not be NULL.
	379	* @param max_size Size limit. Error out if the resource is larger than this.
	380	*
	381	* @return A buffer containing the resource data, or NULL on failure. Must
d9251a2c	382	* be freed by the caller using g_free().
bee24666 DE	383	*
	384	* @private
	385	*/
	386	SR_PRIV void sr_resource_load(struct sr_context ctx,
	387	int type, const char name, size_t size, size_t max_size)
	388	{
	389	struct sr_resource res;
	390	void *buf;
45d835ed	391	size_t res_size;
32ba0d80	392	gssize n_read;
bee24666 DE	393
	394	if (sr_resource_open(ctx, &res, type, name) != SR_OK)
	395	return NULL;
	396
	397	if (res.size > max_size) {
	398	sr_err("Size %" PRIu64 " of '%s' exceeds limit %zu.",
	399	res.size, name, max_size);
	400	sr_resource_close(ctx, &res);
	401	return NULL;
	402	}
45d835ed DE	403	res_size = res.size;
	404
	405	buf = g_try_malloc(res_size);
bee24666 DE	406	if (!buf) {
	407	sr_err("Failed to allocate buffer for '%s'.", name);
	408	sr_resource_close(ctx, &res);
	409	return NULL;
	410	}
	411
45d835ed	412	n_read = sr_resource_read(ctx, &res, buf, res_size);
bee24666 DE	413	sr_resource_close(ctx, &res);
bee24666 DE	414
45d835ed	415	if (n_read < 0 \|\| (size_t)n_read != res_size) {
bee24666 DE	416	if (n_read >= 0)
	417	sr_err("Failed to read '%s': premature end of file.",
	418	name);
	419	g_free(buf);
	420	return NULL;
	421	}
	422
45d835ed	423	*size = res_size;
bee24666 DE	424	return buf;
bee24666 DE	425	}