[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, *env;
	const char *const *datadirs;
	FILE *file = NULL;

	(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;
	}

	env = g_getenv("SIGROK_FIRMWARE_DIR");
	if (!env)
		sr_dbg("SIGROK_FIRMWARE_DIR environment variable not set, ignoring.");
	else
		file = try_open_file(env, "", name);

	if (!file)
		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_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
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;
127c9cec DE	102	#ifdef FIRMWARE_DIR
	103	const char *builtindir;
	104	#endif
1503d457	105	const char subdir, env;
bee24666	106	const char const datadirs;
1503d457	107	FILE *file = NULL;
bee24666 DE	108
	109	(void)cb_data;
	110
	111	switch (res->type) {
	112	case SR_RESOURCE_FIRMWARE:
127c9cec	113	#ifdef FIRMWARE_DIR
bee24666	114	builtindir = FIRMWARE_DIR;
127c9cec	115	#endif
bee24666 DE	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
1503d457 UH	123	env = g_getenv("SIGROK_FIRMWARE_DIR");
	124	if (!env)
	125	sr_dbg("SIGROK_FIRMWARE_DIR environment variable not set, ignoring.");
	126	else
	127	file = try_open_file(env, "", name);
	128
	129	if (!file)
	130	file = try_open_file(g_get_user_data_dir(), subdir, name);
	131
bee24666 DE	132	/*
	133	* Scan the hard-coded directory before the system directories to
	134	* avoid picking up possibly outdated files from a system install.
	135	*/
127c9cec	136	#ifdef FIRMWARE_DIR
bee24666 DE	137	if (!file)
bee24666 DE	138	file = try_open_file(builtindir, "", name);
127c9cec	139	#endif
bee24666 DE	140	if (!file) {
	141	datadirs = g_get_system_data_dirs();
	142	while (*datadirs && !file)
	143	file = try_open_file(*datadirs++, subdir, name);
	144	}
	145	if (!file) {
7ade12b4	146	sr_dbg("Failed to locate '%s'.", name);
bee24666 DE	147	return SR_ERR;
	148	}
	149
	150	filesize = sr_file_get_size(file);
	151	if (filesize < 0) {
	152	sr_err("Failed to obtain size of '%s': %s",
	153	name, g_strerror(errno));
	154	fclose(file);
	155	return SR_ERR;
	156	}
	157	res->size = filesize;
	158	res->handle = file;
	159
	160	return SR_OK;
	161	}
	162
	163	static int resource_close_default(struct sr_resource res, void cb_data)
	164	{
	165	FILE *file;
	166
	167	(void)cb_data;
	168
	169	file = res->handle;
	170	if (!file) {
	171	sr_err("%s: invalid handle.", __func__);
	172	return SR_ERR_ARG;
	173	}
	174
	175	if (fclose(file) < 0) {
	176	sr_err("Failed to close file: %s", g_strerror(errno));
	177	return SR_ERR;
	178	}
	179	res->handle = NULL;
	180
	181	return SR_OK;
	182	}
	183
32ba0d80	184	static gssize resource_read_default(const struct sr_resource *res,
bee24666 DE	185	void buf, size_t count, void cb_data)
	186	{
	187	FILE *file;
	188	size_t n_read;
	189
	190	(void)cb_data;
	191
	192	file = res->handle;
	193	if (!file) {
	194	sr_err("%s: invalid handle.", __func__);
	195	return SR_ERR_ARG;
	196	}
32ba0d80	197	if (count > G_MAXSSIZE) {
bee24666 DE	198	sr_err("%s: count %zu too large.", __func__, count);
	199	return SR_ERR_ARG;
	200	}
	201
	202	n_read = fread(buf, 1, count, file);
	203
	204	if (n_read != count && ferror(file)) {
	205	sr_err("Failed to read resource file: %s", g_strerror(errno));
	206	return SR_ERR;
	207	}
	208	return n_read;
	209	}
	210
	211	/**
	212	* Install resource access hooks.
	213	*
	214	* @param ctx libsigrok context. Must not be NULL.
	215	* @param open_cb Resource open callback, or NULL to unset.
	216	* @param close_cb Resource close callback, or NULL to unset.
	217	* @param read_cb Resource read callback, or NULL to unset.
	218	* @param cb_data User data pointer passed to callbacks.
	219	*
	220	* @retval SR_OK Success.
	221	* @retval SR_ERR_ARG Invalid argument.
	222	*
	223	* @since 0.4.0
	224	*/
	225	SR_API int sr_resource_set_hooks(struct sr_context *ctx,
	226	sr_resource_open_callback open_cb,
	227	sr_resource_close_callback close_cb,
	228	sr_resource_read_callback read_cb, void *cb_data)
	229	{
	230	if (!ctx) {
	231	sr_err("%s: ctx was NULL.", __func__);
	232	return SR_ERR_ARG;
	233	}
	234	if (open_cb && close_cb && read_cb) {
d9251a2c	235	ctx->resource_open_cb = open_cb;
bee24666	236	ctx->resource_close_cb = close_cb;
d9251a2c UH	237	ctx->resource_read_cb = read_cb;
d9251a2c UH	238	ctx->resource_cb_data = cb_data;
bee24666	239	} else if (!open_cb && !close_cb && !read_cb) {
d9251a2c	240	ctx->resource_open_cb = &resource_open_default;
bee24666	241	ctx->resource_close_cb = &resource_close_default;
d9251a2c UH	242	ctx->resource_read_cb = &resource_read_default;
d9251a2c UH	243	ctx->resource_cb_data = ctx;
bee24666 DE	244	} else {
	245	sr_err("%s: inconsistent callback pointers.", __func__);
	246	return SR_ERR_ARG;
	247	}
	248	return SR_OK;
	249	}
	250
	251	/**
	252	* Open resource.
	253	*
	254	* @param ctx libsigrok context. Must not be NULL.
	255	* @param[out] res Resource descriptor to fill in. Must not be NULL.
	256	* @param type Resource type ID.
	257	* @param name Name of the resource. Must not be NULL.
	258	*
	259	* @retval SR_OK Success.
	260	* @retval SR_ERR_ARG Invalid argument.
	261	* @retval SR_ERR Other error.
	262	*
	263	* @private
	264	*/
	265	SR_PRIV int sr_resource_open(struct sr_context *ctx,
	266	struct sr_resource res, int type, const char name)
	267	{
	268	int ret;
	269
	270	res->size = 0;
	271	res->handle = NULL;
	272	res->type = type;
	273
	274	ret = (*ctx->resource_open_cb)(res, name, ctx->resource_cb_data);
	275
	276	if (ret != SR_OK)
7ade12b4 UH	277	sr_err("Failed to open resource '%s' (use loglevel 5/spew for"
7ade12b4 UH	278	" details).", name);
bee24666 DE	279
	280	return ret;
	281	}
	282
	283	/**
	284	* Close resource.
	285	*
	286	* @param ctx libsigrok context. Must not be NULL.
	287	* @param[inout] res Resource descriptor. Must not be NULL.
	288	*
	289	* @retval SR_OK Success.
	290	* @retval SR_ERR_ARG Invalid argument.
	291	* @retval SR_ERR Other error.
	292	*
	293	* @private
	294	*/
	295	SR_PRIV int sr_resource_close(struct sr_context ctx, struct sr_resource res)
	296	{
	297	int ret;
	298
	299	ret = (*ctx->resource_close_cb)(res, ctx->resource_cb_data);
	300
	301	if (ret != SR_OK)
	302	sr_err("Failed to close resource.");
	303
	304	return ret;
	305	}
	306
	307	/**
	308	* Read resource data.
	309	*
	310	* @param ctx libsigrok context. Must not be NULL.
	311	* @param[in] res Resource descriptor. Must not be NULL.
	312	* @param[out] buf Buffer to store @a count bytes into. Must not be NULL.
	313	* @param count Number of bytes to read.
	314	*
	315	* @return The number of bytes actually read, or a negative value on error.
	316	* @retval SR_ERR_ARG Invalid argument.
	317	* @retval SR_ERR Other error.
	318	*
	319	* @private
	320	*/
32ba0d80	321	SR_PRIV gssize sr_resource_read(struct sr_context *ctx,
bee24666 DE	322	const struct sr_resource res, void buf, size_t count)
bee24666 DE	323	{
32ba0d80	324	gssize n_read;
bee24666 DE	325
	326	n_read = (*ctx->resource_read_cb)(res, buf, count,
	327	ctx->resource_cb_data);
	328	if (n_read < 0)
	329	sr_err("Failed to read resource.");
	330
	331	return n_read;
	332	}
	333
	334	/**
	335	* Load a resource into memory.
	336	*
	337	* @param ctx libsigrok context. Must not be NULL.
	338	* @param type Resource type ID.
	339	* @param name Name of the resource. Must not be NULL.
	340	* @param[out] size Size in bytes of the returned buffer. Must not be NULL.
	341	* @param max_size Size limit. Error out if the resource is larger than this.
	342	*
	343	* @return A buffer containing the resource data, or NULL on failure. Must
d9251a2c	344	* be freed by the caller using g_free().
bee24666 DE	345	*
	346	* @private
	347	*/
	348	SR_PRIV void sr_resource_load(struct sr_context ctx,
	349	int type, const char name, size_t size, size_t max_size)
	350	{
	351	struct sr_resource res;
	352	void *buf;
45d835ed	353	size_t res_size;
32ba0d80	354	gssize n_read;
bee24666 DE	355
	356	if (sr_resource_open(ctx, &res, type, name) != SR_OK)
	357	return NULL;
	358
	359	if (res.size > max_size) {
	360	sr_err("Size %" PRIu64 " of '%s' exceeds limit %zu.",
	361	res.size, name, max_size);
	362	sr_resource_close(ctx, &res);
	363	return NULL;
	364	}
45d835ed DE	365	res_size = res.size;
	366
	367	buf = g_try_malloc(res_size);
bee24666 DE	368	if (!buf) {
	369	sr_err("Failed to allocate buffer for '%s'.", name);
	370	sr_resource_close(ctx, &res);
	371	return NULL;
	372	}
	373
45d835ed	374	n_read = sr_resource_read(ctx, &res, buf, res_size);
bee24666 DE	375	sr_resource_close(ctx, &res);
bee24666 DE	376
45d835ed	377	if (n_read < 0 \|\| (size_t)n_read != res_size) {
bee24666 DE	378	if (n_read >= 0)
	379	sr_err("Failed to read '%s': premature end of file.",
	380	name);
	381	g_free(buf);
	382	return NULL;
	383	}
	384
45d835ed	385	*size = res_size;
bee24666 DE	386	return buf;
	387	}
	388
	389	/** @} */