[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;
#ifdef FIRMWARE_DIR
	const char *builtindir;
#endif
	const char *subdir;
	const char *const *datadirs;
	FILE *file;

	(void)cb_data;

	switch (res->type) {
	case SR_RESOURCE_FIRMWARE:
#ifdef FIRMWARE_DIR
		builtindir = FIRMWARE_DIR;
#endif
		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.
	 */
#ifdef FIRMWARE_DIR
	if (!file)
		file = try_open_file(builtindir, "", name);
#endif
	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;
	size_t res_size;
	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;
	}
	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
	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
	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
	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	#ifdef FIRMWARE_DIR
	103	const char *builtindir;
	104	#endif
	105	const char *subdir;
	106	const char const datadirs;
	107	FILE *file;
	108
	109	(void)cb_data;
	110
	111	switch (res->type) {
	112	case SR_RESOURCE_FIRMWARE:
	113	#ifdef FIRMWARE_DIR
	114	builtindir = FIRMWARE_DIR;
	115	#endif
	116	subdir = "sigrok-firmware";
	117	break;
	118	default:
	119	sr_err("%s: unknown type %d.", __func__, res->type);
	120	return SR_ERR_ARG;
	121	}
	122
	123	file = try_open_file(g_get_user_data_dir(), subdir, name);
	124	/*
	125	* Scan the hard-coded directory before the system directories to
	126	* avoid picking up possibly outdated files from a system install.
	127	*/
	128	#ifdef FIRMWARE_DIR
	129	if (!file)
	130	file = try_open_file(builtindir, "", name);
	131	#endif
	132	if (!file) {
	133	datadirs = g_get_system_data_dirs();
	134	while (*datadirs && !file)
	135	file = try_open_file(*datadirs++, subdir, name);
	136	}
	137	if (!file) {
	138	sr_err("Failed to locate '%s'.", name);
	139	return SR_ERR;
	140	}
	141
	142	filesize = sr_file_get_size(file);
	143	if (filesize < 0) {
	144	sr_err("Failed to obtain size of '%s': %s",
	145	name, g_strerror(errno));
	146	fclose(file);
	147	return SR_ERR;
	148	}
	149	res->size = filesize;
	150	res->handle = file;
	151
	152	return SR_OK;
	153	}
	154
	155	static int resource_close_default(struct sr_resource res, void cb_data)
	156	{
	157	FILE *file;
	158
	159	(void)cb_data;
	160
	161	file = res->handle;
	162	if (!file) {
	163	sr_err("%s: invalid handle.", __func__);
	164	return SR_ERR_ARG;
	165	}
	166
	167	if (fclose(file) < 0) {
	168	sr_err("Failed to close file: %s", g_strerror(errno));
	169	return SR_ERR;
	170	}
	171	res->handle = NULL;
	172
	173	return SR_OK;
	174	}
	175
	176	static ssize_t resource_read_default(const struct sr_resource *res,
	177	void buf, size_t count, void cb_data)
	178	{
	179	FILE *file;
	180	size_t n_read;
	181
	182	(void)cb_data;
	183
	184	file = res->handle;
	185	if (!file) {
	186	sr_err("%s: invalid handle.", __func__);
	187	return SR_ERR_ARG;
	188	}
	189	if (count > SSIZE_MAX) {
	190	sr_err("%s: count %zu too large.", __func__, count);
	191	return SR_ERR_ARG;
	192	}
	193
	194	n_read = fread(buf, 1, count, file);
	195
	196	if (n_read != count && ferror(file)) {
	197	sr_err("Failed to read resource file: %s", g_strerror(errno));
	198	return SR_ERR;
	199	}
	200	return n_read;
	201	}
	202
	203	/**
	204	* Install resource access hooks.
	205	*
	206	* @param ctx libsigrok context. Must not be NULL.
	207	* @param open_cb Resource open callback, or NULL to unset.
	208	* @param close_cb Resource close callback, or NULL to unset.
	209	* @param read_cb Resource read callback, or NULL to unset.
	210	* @param cb_data User data pointer passed to callbacks.
	211	*
	212	* @retval SR_OK Success.
	213	* @retval SR_ERR_ARG Invalid argument.
	214	*
	215	* @since 0.4.0
	216	*/
	217	SR_API int sr_resource_set_hooks(struct sr_context *ctx,
	218	sr_resource_open_callback open_cb,
	219	sr_resource_close_callback close_cb,
	220	sr_resource_read_callback read_cb, void *cb_data)
	221	{
	222	if (!ctx) {
	223	sr_err("%s: ctx was NULL.", __func__);
	224	return SR_ERR_ARG;
	225	}
	226	if (open_cb && close_cb && read_cb) {
	227	ctx->resource_open_cb = open_cb;
	228	ctx->resource_close_cb = close_cb;
	229	ctx->resource_read_cb = read_cb;
	230	ctx->resource_cb_data = cb_data;
	231	} else if (!open_cb && !close_cb && !read_cb) {
	232	ctx->resource_open_cb = &resource_open_default;
	233	ctx->resource_close_cb = &resource_close_default;
	234	ctx->resource_read_cb = &resource_read_default;
	235	ctx->resource_cb_data = ctx;
	236	} else {
	237	sr_err("%s: inconsistent callback pointers.", __func__);
	238	return SR_ERR_ARG;
	239	}
	240	return SR_OK;
	241	}
	242
	243	/**
	244	* Open resource.
	245	*
	246	* @param ctx libsigrok context. Must not be NULL.
	247	* @param[out] res Resource descriptor to fill in. Must not be NULL.
	248	* @param type Resource type ID.
	249	* @param name Name of the resource. Must not be NULL.
	250	*
	251	* @retval SR_OK Success.
	252	* @retval SR_ERR_ARG Invalid argument.
	253	* @retval SR_ERR Other error.
	254	*
	255	* @private
	256	*/
	257	SR_PRIV int sr_resource_open(struct sr_context *ctx,
	258	struct sr_resource res, int type, const char name)
	259	{
	260	int ret;
	261
	262	res->size = 0;
	263	res->handle = NULL;
	264	res->type = type;
	265
	266	ret = (*ctx->resource_open_cb)(res, name, ctx->resource_cb_data);
	267
	268	if (ret != SR_OK)
	269	sr_err("Failed to open resource '%s'.", name);
	270
	271	return ret;
	272	}
	273
	274	/**
	275	* Close resource.
	276	*
	277	* @param ctx libsigrok context. Must not be NULL.
	278	* @param[inout] res Resource descriptor. Must not be NULL.
	279	*
	280	* @retval SR_OK Success.
	281	* @retval SR_ERR_ARG Invalid argument.
	282	* @retval SR_ERR Other error.
	283	*
	284	* @private
	285	*/
	286	SR_PRIV int sr_resource_close(struct sr_context ctx, struct sr_resource res)
	287	{
	288	int ret;
	289
	290	ret = (*ctx->resource_close_cb)(res, ctx->resource_cb_data);
	291
	292	if (ret != SR_OK)
	293	sr_err("Failed to close resource.");
	294
	295	return ret;
	296	}
	297
	298	/**
	299	* Read resource data.
	300	*
	301	* @param ctx libsigrok context. Must not be NULL.
	302	* @param[in] res Resource descriptor. Must not be NULL.
	303	* @param[out] buf Buffer to store @a count bytes into. Must not be NULL.
	304	* @param count Number of bytes to read.
	305	*
	306	* @return The number of bytes actually read, or a negative value on error.
	307	* @retval SR_ERR_ARG Invalid argument.
	308	* @retval SR_ERR Other error.
	309	*
	310	* @private
	311	*/
	312	SR_PRIV ssize_t sr_resource_read(struct sr_context *ctx,
	313	const struct sr_resource res, void buf, size_t count)
	314	{
	315	ssize_t n_read;
	316
	317	n_read = (*ctx->resource_read_cb)(res, buf, count,
	318	ctx->resource_cb_data);
	319	if (n_read < 0)
	320	sr_err("Failed to read resource.");
	321
	322	return n_read;
	323	}
	324
	325	/**
	326	* Load a resource into memory.
	327	*
	328	* @param ctx libsigrok context. Must not be NULL.
	329	* @param type Resource type ID.
	330	* @param name Name of the resource. Must not be NULL.
	331	* @param[out] size Size in bytes of the returned buffer. Must not be NULL.
	332	* @param max_size Size limit. Error out if the resource is larger than this.
	333	*
	334	* @return A buffer containing the resource data, or NULL on failure. Must
	335	* be freed by the caller using g_free().
	336	*
	337	* @private
	338	*/
	339	SR_PRIV void sr_resource_load(struct sr_context ctx,
	340	int type, const char name, size_t size, size_t max_size)
	341	{
	342	struct sr_resource res;
	343	void *buf;
	344	size_t res_size;
	345	ssize_t n_read;
	346
	347	if (sr_resource_open(ctx, &res, type, name) != SR_OK)
	348	return NULL;
	349
	350	if (res.size > max_size) {
	351	sr_err("Size %" PRIu64 " of '%s' exceeds limit %zu.",
	352	res.size, name, max_size);
	353	sr_resource_close(ctx, &res);
	354	return NULL;
	355	}
	356	res_size = res.size;
	357
	358	buf = g_try_malloc(res_size);
	359	if (!buf) {
	360	sr_err("Failed to allocate buffer for '%s'.", name);
	361	sr_resource_close(ctx, &res);
	362	return NULL;
	363	}
	364
	365	n_read = sr_resource_read(ctx, &res, buf, res_size);
	366	sr_resource_close(ctx, &res);
	367
	368	if (n_read < 0 \|\| (size_t)n_read != res_size) {
	369	if (n_read >= 0)
	370	sr_err("Failed to read '%s': premature end of file.",
	371	name);
	372	g_free(buf);
	373	return NULL;
	374	}
	375
	376	*size = res_size;
	377	return buf;
	378	}
	379
	380	/** @} */