[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)
			sr_dbg("SIGROK_FIRMWARE_DIR environment variable not set, ignoring.");
		else
			l = g_slist_append(l, g_strdup(env));
	}

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		 * avoid picking up possibly outdated files from a system install.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	70	* avoid picking up possibly outdated files from a system install.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