freebsd-dev/sys/dev/bhnd/nvram/bhnd_nvram_data_bcmraw.c

/*-
 * Copyright (c) 2016 Landon Fuller <landonf@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
 *    redistribution must be conditioned upon including a substantially
 *    similar Disclaimer requirement for further binary redistribution.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGES.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#ifdef _KERNEL

#include <sys/param.h>
#include <sys/ctype.h>
#include <sys/malloc.h>
#include <sys/systm.h>

#else /* !_KERNEL */

#include <ctype.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#endif /* _KERNEL */

#include "bhnd_nvram_private.h"

#include "bhnd_nvram_datavar.h"

/*
 * Broadcom-RAW NVRAM data class.
 * 
 * The Broadcom NVRAM NUL-delimited ASCII format is used by most
 * Broadcom SoCs.
 * 
 * The NVRAM data is encoded as a stream of of NUL-terminated 'key=value'
 * strings; the end of the stream is denoted by a single extra NUL character.
 */

struct bhnd_nvram_bcmraw;

/** BCM-RAW NVRAM data class instance */
struct bhnd_nvram_bcmraw {
	struct bhnd_nvram_data		 nv;	/**< common instance state */
	char				*data;	/**< backing buffer */
	size_t				 size;	/**< buffer size */
	size_t				 count;	/**< variable count */
};

BHND_NVRAM_DATA_CLASS_DEFN(bcmraw, "Broadcom (RAW)",
   sizeof(struct bhnd_nvram_bcmraw))

static int
bhnd_nvram_bcmraw_probe(struct bhnd_nvram_io *io)
{
	char	 envp[16];
	size_t	 envp_len;
	int	 error;

	/*
	 * Fetch the initial bytes to try to identify BCM data.
	 * 
	 * We always assert a low probe priority, as we only scan the initial
	 * bytes of the file.
	 */
	envp_len = bhnd_nv_ummin(sizeof(envp), bhnd_nvram_io_getsize(io));
	if ((error = bhnd_nvram_io_read(io, 0x0, envp, envp_len)))
		return (error);

	/* A zero-length BCM-RAW buffer should contain a single terminating
	 * NUL */
	if (envp_len == 0)
		return (ENXIO);

	if (envp_len == 1) {
		if (envp[0] != '\0')
			return (ENXIO);

		return (BHND_NVRAM_DATA_PROBE_MAYBE);
	}

	/* Don't match on non-ASCII, non-printable data */
	for (size_t i = 0; i < envp_len; i++) {
		char c = envp[i];
		if (envp[i] == '\0')
			break;

		if (!bhnd_nv_isprint(c))
			return (ENXIO);
	}

	/* The first character should be a valid key char */
	if (!bhnd_nv_isalpha(envp[0]))
		return (ENXIO);

	return (BHND_NVRAM_DATA_PROBE_MAYBE);
}

/**
 * Initialize @p bcm with the provided NVRAM data mapped by @p src.
 * 
 * @param bcm A newly allocated data instance.
 */
static int
bhnd_nvram_bcmraw_init(struct bhnd_nvram_bcmraw *bcm, struct bhnd_nvram_io *src)
{
	size_t	 io_size;
	size_t	 capacity, offset;
	int	 error;

	/* Fetch the input image size */
	io_size = bhnd_nvram_io_getsize(src);

	/* Allocate a buffer large enough to hold the NVRAM image, and
	 * an extra EOF-signaling NUL (on the chance it's missing from the
	 * source data) */
	if (io_size == SIZE_MAX)
		return (ENOMEM);

	capacity = io_size + 1 /* room for extra NUL */;
	bcm->size = io_size;
	if ((bcm->data = bhnd_nv_malloc(capacity)) == NULL)
		return (ENOMEM);

	/* Copy in the NVRAM image */
	if ((error = bhnd_nvram_io_read(src, 0x0, bcm->data, io_size)))
		return (error);

	/* Process the buffer */
	bcm->count = 0;
	for (offset = 0; offset < bcm->size; offset++) {
		char		*envp;
		const char	*name, *value;
		size_t		 envp_len;
		size_t		 name_len, value_len;

		/* Parse the key=value string */
		envp = (char *) (bcm->data + offset);
		envp_len = strnlen(envp, bcm->size - offset);
		error = bhnd_nvram_parse_env(envp, envp_len, '=', &name,
					     &name_len, &value, &value_len);
		if (error) {
			BHND_NV_LOG("error parsing envp at offset %#zx: %d\n",
			    offset, error);
			return (error);
		}

		/* Insert a '\0' character, replacing the '=' delimiter and
		 * allowing us to vend references directly to the variable
		 * name */
		*(envp + name_len) = '\0';

		/* Add to variable count */
		bcm->count++;

		/* Seek past the value's terminating '\0' */
		offset += envp_len;
		if (offset == io_size) {
			BHND_NV_LOG("missing terminating NUL at offset %#zx\n",
			    offset);
			return (EINVAL);
		}

		/* If we hit EOF without finding a terminating NUL
		 * byte, we need to append it */
		if (++offset == bcm->size) {
			BHND_NV_ASSERT(offset < capacity,
			    ("appending past end of buffer"));
			bcm->size++;
			*(bcm->data + offset) = '\0';
		}

		/* Check for explicit EOF (encoded as a single empty NUL
		 * terminated string) */
		if (*(bcm->data + offset) == '\0')
			break;
	}

	/* Reclaim any unused space in he backing buffer */
	if (offset < bcm->size) {
		bcm->data = bhnd_nv_reallocf(bcm->data, bcm->size);
		if (bcm->data == NULL)
			return (ENOMEM);
	}

	return (0);
}

static int
bhnd_nvram_bcmraw_new(struct bhnd_nvram_data *nv, struct bhnd_nvram_io *io)
{
	struct bhnd_nvram_bcmraw	*bcm;
	int				 error;

	bcm = (struct bhnd_nvram_bcmraw *)nv;

	/* Parse the BCM input data and initialize our backing
	 * data representation */
	if ((error = bhnd_nvram_bcmraw_init(bcm, io))) {
		bhnd_nvram_bcmraw_free(nv);
		return (error);
	}

	return (0);
}

static void
bhnd_nvram_bcmraw_free(struct bhnd_nvram_data *nv)
{
	struct bhnd_nvram_bcmraw *bcm = (struct bhnd_nvram_bcmraw *)nv;

	if (bcm->data != NULL)
		bhnd_nv_free(bcm->data);
}

static size_t
bhnd_nvram_bcmraw_count(struct bhnd_nvram_data *nv)
{
	struct bhnd_nvram_bcmraw *bcm = (struct bhnd_nvram_bcmraw *)nv;

	return (bcm->count);
}

static int
bhnd_nvram_bcmraw_size(struct bhnd_nvram_data *nv, size_t *size)
{
	return (bhnd_nvram_bcmraw_serialize(nv, NULL, size));
}

static int
bhnd_nvram_bcmraw_serialize(struct bhnd_nvram_data *nv, void *buf, size_t *len)
{
	struct bhnd_nvram_bcmraw	*bcm;
	char * const			 p = (char *)buf;
	size_t				 limit;
	size_t				 offset;

	bcm = (struct bhnd_nvram_bcmraw *)nv;

	/* Save the output buffer limit */
	if (buf == NULL)
		limit = 0;
	else
		limit = *len;

	/* The serialized form will be exactly the length
	 * of our backing buffer representation */
	*len = bcm->size;

	/* Skip serialization if not requested, or report ENOMEM if
	 * buffer is too small */
	if (buf == NULL) {
		return (0);
	} else if (*len > limit) {
		return (ENOMEM);
	}

	/* Write all variables to the output buffer */
	memcpy(buf, bcm->data, *len);

	/* Rewrite all '\0' delimiters back to '=' */
	offset = 0;
	while (offset < bcm->size) {
		size_t name_len, value_len;

		name_len = strlen(p + offset);

		/* EOF? */
		if (name_len == 0) {
			BHND_NV_ASSERT(*(p + offset) == '\0',
			    ("no NUL terminator"));

			offset++;
			break;
		}

		/* Rewrite 'name\0' to 'name=' */
		offset += name_len;
		BHND_NV_ASSERT(*(p + offset) == '\0', ("incorrect offset"));

		*(p + offset) = '=';
		offset++;

		value_len = strlen(p + offset);
		offset += value_len + 1;
	}

	return (0);
}

static uint32_t
bhnd_nvram_bcmraw_caps(struct bhnd_nvram_data *nv)
{
	return (BHND_NVRAM_DATA_CAP_READ_PTR|BHND_NVRAM_DATA_CAP_DEVPATHS);
}

static const char *
bhnd_nvram_bcmraw_next(struct bhnd_nvram_data *nv, void **cookiep)
{
	struct bhnd_nvram_bcmraw	*bcm;
	const char			*envp;

	bcm = (struct bhnd_nvram_bcmraw *)nv;

	if (*cookiep == NULL) {
		/* Start at the first NVRAM data record */
		envp = bcm->data;
	} else {
		/* Seek to next record */
		envp = *cookiep;
		envp += strlen(envp) + 1;	/* key + '\0' */
		envp += strlen(envp) + 1;	/* value + '\0' */
	}

	/* EOF? */
	if (*envp == '\0')
		return (NULL);

	*cookiep = (void *)(uintptr_t)envp;
	return (envp);
}

static void *
bhnd_nvram_bcmraw_find(struct bhnd_nvram_data *nv, const char *name)
{
	return (bhnd_nvram_data_generic_find(nv, name));
}

static int
bhnd_nvram_bcmraw_getvar(struct bhnd_nvram_data *nv, void *cookiep, void *buf,
    size_t *len, bhnd_nvram_type type)
{
	return (bhnd_nvram_data_generic_rp_getvar(nv, cookiep, buf, len, type));
}

static const void *
bhnd_nvram_bcmraw_getvar_ptr(struct bhnd_nvram_data *nv, void *cookiep,
    size_t *len, bhnd_nvram_type *type)
{
	const char *envp;

	/* Cookie points to key\0value\0 -- get the value address */
	envp = cookiep;
	envp += strlen(envp) + 1;	/* key + '\0' */
	*len = strlen(envp) + 1;	/* value + '\0' */
	*type = BHND_NVRAM_TYPE_STRING;

	return (envp);
}

static const char *
bhnd_nvram_bcmraw_getvar_name(struct bhnd_nvram_data *nv, void *cookiep)
{
	/* Cookie points to key\0value\0 */
	return (cookiep);
}