path: root/src/target/image.c

/***************************************************************************
 *   Copyright (C) 2007 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   Copyright (C) 2008 by Spencer Oliver                                  *
 *   spen@spen-soft.co.uk                                                  *
 *                                                                         *
 *   Copyright (C) 2009 by Franck Hereson                                  *
 *   franck.hereson@secad.fr                                               *
 *                                                                         *
 *   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 2 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/>. *
 ***************************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "image.h"
#include "target.h"
#include <helper/log.h>

/* convert ELF header field to host endianness */
#define field16(elf, field) \
	((elf->endianness == ELFDATA2LSB) ? \
	le_to_h_u16((uint8_t *)&field) : be_to_h_u16((uint8_t *)&field))

#define field32(elf, field) \
	((elf->endianness == ELFDATA2LSB) ? \
	le_to_h_u32((uint8_t *)&field) : be_to_h_u32((uint8_t *)&field))

static int autodetect_image_type(struct image *image, const char *url)
{
	int retval;
	struct fileio *fileio;
	size_t read_bytes;
	uint8_t buffer[9];

	/* read the first 4 bytes of image */
	retval = fileio_open(&fileio, url, FILEIO_READ, FILEIO_BINARY);
	if (retval != ERROR_OK)
		return retval;
	retval = fileio_read(fileio, 9, buffer, &read_bytes);

	if (retval == ERROR_OK) {
		if (read_bytes != 9)
			retval = ERROR_FILEIO_OPERATION_FAILED;
	}
	fileio_close(fileio);

	if (retval != ERROR_OK)
		return retval;

	/* check header against known signatures */
	if (strncmp((char *)buffer, ELFMAG, SELFMAG) == 0) {
		LOG_DEBUG("ELF image detected.");
		image->type = IMAGE_ELF;
	} else if ((buffer[0] == ':')	/* record start byte */
		&& (isxdigit(buffer[1]))
		&& (isxdigit(buffer[2]))
		&& (isxdigit(buffer[3]))
		&& (isxdigit(buffer[4]))
		&& (isxdigit(buffer[5]))
		&& (isxdigit(buffer[6]))
		&& (buffer[7] == '0')	/* record type : 00 -> 05 */
		&& (buffer[8] >= '0') && (buffer[8] < '6')) {
		LOG_DEBUG("IHEX image detected.");
		image->type = IMAGE_IHEX;
	} else if ((buffer[0] == 'S')	/* record start byte */
		&& (isxdigit(buffer[1]))
		&& (isxdigit(buffer[2]))
		&& (isxdigit(buffer[3]))
		&& (buffer[1] >= '0') && (buffer[1] < '9')) {
		LOG_DEBUG("S19 image detected.");
		image->type = IMAGE_SRECORD;
	} else
		image->type = IMAGE_BINARY;

	return ERROR_OK;
}

static int identify_image_type(struct image *image, const char *type_string, const char *url)
{
	if (type_string) {
		if (!strcmp(type_string, "bin"))
			image->type = IMAGE_BINARY;
		else if (!strcmp(type_string, "ihex"))
			image->type = IMAGE_IHEX;
		else if (!strcmp(type_string, "elf"))
			image->type = IMAGE_ELF;
		else if (!strcmp(type_string, "mem"))
			image->type = IMAGE_MEMORY;
		else if (!strcmp(type_string, "s19"))
			image->type = IMAGE_SRECORD;
		else if (!strcmp(type_string, "build"))
			image->type = IMAGE_BUILDER;
		else
			return ERROR_IMAGE_TYPE_UNKNOWN;
	} else
		return autodetect_image_type(image, url);

	return ERROR_OK;
}

static int image_ihex_buffer_complete_inner(struct image *image,
	char *lpszLine,
	struct imagesection *section)
{
	struct image_ihex *ihex = image->type_private;
	struct fileio *fileio = ihex->fileio;
	uint32_t full_address = 0x0;
	uint32_t cooked_bytes;
	int i;

	/* we can't determine the number of sections that we'll have to create ahead of time,
	 * so we locally hold them until parsing is finished */

	size_t filesize;
	int retval;
	retval = fileio_size(fileio, &filesize);
	if (retval != ERROR_OK)
		return retval;

	ihex->buffer = malloc(filesize >> 1);
	cooked_bytes = 0x0;
	image->num_sections = 0;
	section[image->num_sections].private = &ihex->buffer[cooked_bytes];
	section[image->num_sections].base_address = 0x0;
	section[image->num_sections].size = 0x0;
	section[image->num_sections].flags = 0;

	while (fileio_fgets(fileio, 1023, lpszLine) == ERROR_OK) {
		uint32_t count;
		uint32_t address;
		uint32_t record_type;
		uint32_t checksum;
		uint8_t cal_checksum = 0;
		size_t bytes_read = 0;

		if (lpszLine[0] == '#')
			continue;

		if (sscanf(&lpszLine[bytes_read], ":%2" SCNx32 "%4" SCNx32 "%2" SCNx32, &count,
			&address, &record_type) != 3)
			return ERROR_IMAGE_FORMAT_ERROR;
		bytes_read += 9;

		cal_checksum += (uint8_t)count;
		cal_checksum += (uint8_t)(address >> 8);
		cal_checksum += (uint8_t)address;
		cal_checksum += (uint8_t)record_type;

		if (record_type == 0) {	/* Data Record */
			if ((full_address & 0xffff) != address) {
				/* we encountered a nonconsecutive location, create a new section,
				 * unless the current section has zero size, in which case this specifies
				 * the current section's base address
				 */
				if (section[image->num_sections].size != 0) {
					image->num_sections++;
					if (image->num_sections >= IMAGE_MAX_SECTIONS) {
						/* too many sections */
						LOG_ERROR("Too many sections found in IHEX file");
						return ERROR_IMAGE_FORMAT_ERROR;
					}
					section[image->num_sections].size = 0x0;
					section[image->num_sections].flags = 0;
					section[image->num_sections].private =
						&ihex->buffer[cooked_bytes];
				}
				section[image->num_sections].base_address =
					(full_address & 0xffff0000) | address;
				full_address = (full_address & 0xffff0000) | address;
			}

			while (count-- > 0) {
				unsigned value;
				sscanf(&lpszLine[bytes_read], "%2x", &value);
				ihex->buffer[cooked_bytes] = (uint8_t)value;
				cal_checksum += (uint8_t)ihex->buffer[cooked_bytes];
				bytes_read += 2;
				cooked_bytes += 1;
				section[image->num_sections].size += 1;
				full_address++;
			}
		} else if (record_type == 1) {	/* End of File Record */
			/* finish the current section */
			image->num_sections++;

			/* copy section information */
			image->sections = malloc(sizeof(struct imagesection) * image->num_sections);
			for (i = 0; i < image->num_sections; i++) {
				image->sections[i].private = section[i].private;
				image->sections[i].base_address = section[i].base_address;
				image->sections[i].size = section[i].size;
				image->sections[i].flags = section[i].flags;
			}

			return ERROR_OK;
		} else if (record_type == 2) {	/* Linear Address Record */
			uint16_t upper_address;

			sscanf(&lpszLine[bytes_read], "%4hx", &upper_address);
			cal_checksum += (uint8_t)(upper_address >> 8);
			cal_checksum += (uint8_t)upper_address;
			bytes_read += 4;

			if ((full_address >> 4) != upper_address) {
				/* we encountered a nonconsecutive location, create a new section,
				 * unless the current section has zero size, in which case this specifies
				 * the current section's base address
				 */
				if (section[image->num_sections].size != 0) {
					image->num_sections++;
					if (image->num_sections >= IMAGE_MAX_SECTIONS) {
						/* too many sections */
						LOG_ERROR("Too many sections found in IHEX file");
						return ERROR_IMAGE_FORMAT_ERROR;
					}
					section[image->num_sections].size = 0x0;
					section[image->num_sections].flags = 0;
					section[image->num_sections].private =
						&ihex->buffer[cooked_bytes];
				}
				section[image->num_sections].base_address =
					(full_address & 0xffff) | (upper_address << 4);
				full_address = (full_address & 0xffff) | (upper_address << 4);
			}
		} else if (record_type == 3) {	/* Start Segment Address Record */
			uint32_t dummy;

			/* "Start Segment Address Record" will not be supported
			 * but we must consume it, and do not create an error.  */
			while (count-- > 0) {
				sscanf(&lpszLine[bytes_read], "%2" SCNx32, &dummy);
				cal_checksum += (uint8_t)dummy;
				bytes_read += 2;
			}
		} else if (record_type == 4) {	/* Extended Linear Address Record */
			uint16_t upper_address;

			sscanf(&lpszLine[bytes_read], "%4hx", &upper_address);
			cal_checksum += (uint8_t)(upper_address >> 8);
			cal_checksum += (uint8_t)upper_address;
			bytes_read += 4;

			if ((full_address >> 16) != upper_address) {
				/* we encountered a nonconsecutive location, create a new section,
				 * unless the current section has zero size, in which case this specifies
				 * the current section's base address
				 */
				if (section[image->num_sections].size != 0) {
					image->num_sections++;
					if (image->num_sections >= IMAGE_MAX_SECTIONS) {
						/* too many sections */
						LOG_ERROR("Too many sections found in IHEX file");
						return ERROR_IMAGE_FORMAT_ERROR;
					}
					section[image->num_sections].size = 0x0;
					section[image->num_sections].flags = 0;
					section[image->num_sections].private =
						&ihex->buffer[cooked_bytes];
				}
				section[image->num_sections].base_address =
					(full_address & 0xffff) | (upper_address << 16);
				full_address = (full_address & 0xffff) | (upper_address << 16);
			}
		} else if (record_type == 5) {	/* Start Linear Address Record */
			uint32_t start_address;

			sscanf(&lpszLine[bytes_read], "%8" SCNx32, &start_address);
			cal_checksum += (uint8_t)(start_address >> 24);
			cal_checksum += (uint8_t)(start_address >> 16);
			cal_checksum += (uint8_t)(start_address >> 8);
			cal_checksum += (uint8_t)start_address;
			bytes_read += 8;

			image->start_address_set = 1;
			image->start_address = be_to_h_u32((uint8_t *)&start_address);
		} else {
			LOG_ERROR("unhandled IHEX record type: %i", (int)record_type);
			return ERROR_IMAGE_FORMAT_ERROR;
		}

		sscanf(&lpszLine[bytes_read], "%2" SCNx32, &checksum);

		if ((uint8_t)checksum != (uint8_t)(~cal_checksum + 1)) {
			/* checksum failed */
			LOG_ERROR("incorrect record checksum found in IHEX file");
			return ERROR_IMAGE_CHECKSUM;
		}
	}

	LOG_ERROR("premature end of IHEX file, no end-of-file record found");
	return ERROR_IMAGE_FORMAT_ERROR;
}

/**
 * Allocate memory dynamically instead of on the stack. This
 * is important w/embedded hosts.
 */
static int image_ihex_buffer_complete(struct image *image)
{
	char *lpszLine = malloc(1023);
	if (lpszLine == NULL) {
		LOG_ERROR("Out of memory");
		return ERROR_FAIL;
	}
	struct imagesection *section = malloc(sizeof(struct imagesection) * IMAGE_MAX_SECTIONS);
	if (section == NULL) {
		free(lpszLine);
		LOG_ERROR("Out of memory");
		return ERROR_FAIL;
	}
	int retval;

	retval = image_ihex_buffer_complete_inner(image, lpszLine, section);

	free(section);
	free(lpszLine);

	return retval;
}

static int image_elf_read_headers(struct image *image)
{
	struct image_elf *elf = image->type_private;
	size_t read_bytes;
	uint32_t i, j;
	int retval;
	uint32_t nload, load_to_vaddr = 0;

	elf->header = malloc(sizeof(Elf32_Ehdr));

	if (elf->header == NULL) {
		LOG_ERROR("insufficient memory to perform operation ");
		return ERROR_FILEIO_OPERATION_FAILED;
	}

	retval = fileio_read(elf->fileio, sizeof(Elf32_Ehdr), (uint8_t *)elf->header, &read_bytes);
	if (retval != ERROR_OK) {
		LOG_ERROR("cannot read ELF file header, read failed");
		return ERROR_FILEIO_OPERATION_FAILED;
	}
	if (read_bytes != sizeof(Elf32_Ehdr)) {
		LOG_ERROR("cannot read ELF file header, only partially read");
		return ERROR_FILEIO_OPERATION_FAILED;
	}

	if (strncmp((char *)elf->header->e_ident, ELFMAG, SELFMAG) != 0) {
		LOG_ERROR("invalid ELF file, bad magic number");
		return ERROR_IMAGE_FORMAT_ERROR;
	}
	if (elf->header->e_ident[EI_CLASS] != ELFCLASS32) {
		LOG_ERROR("invalid ELF file, only 32bits files are supported");
		return ERROR_IMAGE_FORMAT_ERROR;
	}

	elf->endianness = elf->header->e_ident[EI_DATA];
	if ((elf->endianness != ELFDATA2LSB)
		&& (elf->endianness != ELFDATA2MSB)) {
		LOG_ERROR("invalid ELF file, unknown endianness setting");
		return ERROR_IMAGE_FORMAT_ERROR;
	}

	elf->segment_count = field16(elf, elf->header->e_phnum);
	if (elf->segment_count == 0) {
		LOG_ERROR("invalid ELF file, no program headers");
		return ERROR_IMAGE_FORMAT_ERROR;
	}

	retval = fileio_seek(elf->fileio, field32(elf, elf->header->e_phoff));
	if (retval != ERROR_OK) {
		LOG_ERROR("cannot seek to ELF program header table, read failed");
		return retval;
	}

	elf->segments = malloc(elf->segment_count*sizeof(Elf32_Phdr));
	if (elf->segments == NULL) {
		LOG_ERROR("insufficient memory to perform operation ");
		return ERROR_FILEIO_OPERATION_FAILED;
	}

	retval = fileio_read(elf->fileio, elf->segment_count*sizeof(Elf32_Phdr),
			(uint8_t *)elf->segments, &read_bytes);
	if (retval != ERROR_OK) {
		LOG_ERROR("cannot read ELF segment headers, read failed");
		return retval;
	}
	if (read_bytes != elf->segment_count*sizeof(Elf32_Phdr)) {
		LOG_ERROR("cannot read ELF segment headers, only partially read");
		return ERROR_FILEIO_OPERATION_FAILED;
	}

	/* count useful segments (loadable), ignore BSS section */
	image->num_sections = 0;
	for (i = 0; i < elf->segment_count; i++)
		if ((field32(elf,
			elf->segments[i].p_type) == PT_LOAD) &&
			(field32(elf, elf->segments[i].p_filesz) != 0))
			image->num_sections++;

	assert(image->num_sections > 0);

	/**
	 * some ELF linkers produce binaries with *all* the program header
	 * p_paddr fields zero (there can be however one loadable segment
	 * that has valid physical address 0x0).
	 * If we have such a binary with more than
	 * one PT_LOAD header, then use p_vaddr instead of p_paddr
	 * (ARM ELF standard demands p_paddr = 0 anyway, and BFD
	 * library uses this approach to workaround zero-initialized p_paddrs
	 * when obtaining lma - look at elf.c of BDF)
	 */
	for (nload = 0, i = 0; i < elf->segment_count; i++)
		if (elf->segments[i].p_paddr != 0)
			break;
		else if ((field32(elf,
			elf->segments[i].p_type) == PT_LOAD) &&
			(field32(elf, elf->segments[i].p_memsz) != 0))
			++nload;

	if (i >= elf->segment_count && nload > 1)
		load_to_vaddr = 1;

	/* alloc and fill sections array with loadable segments */
	image->sections = malloc(image->num_sections * sizeof(struct imagesection));
	for (i = 0, j = 0; i < elf->segment_count; i++) {
		if ((field32(elf,
			elf->segments[i].p_type) == PT_LOAD) &&
			(field32(elf, elf->segments[i].p_filesz) != 0)) {
			image->sections[j].size = field32(elf, elf->segments[i].p_filesz);
			if (load_to_vaddr)
				image->sections[j].base_address = field32(elf,
						elf->segments[i].p_vaddr);
			else
				image->sections[j].base_address = field32(elf,
						elf->segments[i].p_paddr);
			image->sections[j].private = &elf->segments[i];
			image->sections[j].flags = field32(elf, elf->segments[i].p_flags);
			j++;
		}
	}

	image->start_address_set = 1;
	image->start_address = field32(elf, elf->header->e_entry);

	return ERROR_OK;
}

static int image_elf_read_section(struct image *image,
	int section,
	uint32_t offset,
	uint32_t size,
	uint8_t *buffer,
	size_t *size_read)
{
	struct image_elf *elf = image->type_private;
	Elf32_Phdr *segment = (Elf32_Phdr *)image->sections[section].private;
	size_t read_size, really_read;
	int retval;

	*size_read = 0;

	LOG_DEBUG("load segment %d at 0x%" PRIx32 " (sz = 0x%" PRIx32 ")", section, offset, size);

	/* read initialized data in current segment if any */
	if (offset < field32(elf, segment->p_filesz)) {
		/* maximal size present in file for the current segment */
		read_size = MIN(size, field32(elf, segment->p_filesz) - offset);
		LOG_DEBUG("read elf: size = 0x%zu at 0x%" PRIx32 "", read_size,
			field32(elf, segment->p_offset) + offset);
		/* read initialized area of the segment */
		retval = fileio_seek(elf->fileio, field32(elf, segment->p_offset) + offset);
		if (retval != ERROR_OK) {
			LOG_ERROR("cannot find ELF segment content, seek failed");
			return retval;
		}
		retval = fileio_read(elf->fileio, read_size, buffer, &really_read);
		if (retval != ERROR_OK) {
			LOG_ERROR("cannot read ELF segment content, read failed");
			return retval;
		}
		size -= read_size;
		*size_read += read_size;
		/* need more data ? */
		if (!size)
			return ERROR_OK;
	}

	return ERROR_OK;
}

static int image_mot_buffer_complete_inner(struct image *image,
	char *lpszLine,
	struct imagesection *section)
{
	struct image_mot *mot = image->type_private;
	struct fileio *fileio = mot->fileio;
	uint32_t full_address = 0x0;
	uint32_t cooked_bytes;
	int i;

	/* we can't determine the number of sections that we'll have to create ahead of time,
	 * so we locally hold them until parsing is finished */

	int retval;
	size_t filesize;
	retval = fileio_size(fileio, &filesize);
	if (retval != ERROR_OK)
		return retval;

	mot->buffer = malloc(filesize >> 1);
	cooked_bytes = 0x0;
	image->num_sections = 0;
	section[image->num_sections].private = &mot->buffer[cooked_bytes];
	section[image->num_sections].base_address = 0x0;
	section[image->num_sections].size = 0x0;
	section[image->num_sections].flags = 0;

	while (fileio_fgets(fileio, 1023, lpszLine) == ERROR_OK) {
		uint32_t count;
		uint32_t address;
		uint32_t record_type;
		uint32_t checksum;
		uint8_t cal_checksum = 0;
		uint32_t bytes_read = 0;

		/* get record type and record length */
		if (sscanf(&lpszLine[bytes_read], "S%1" SCNx32 "%2" SCNx32, &record_type,
			&count) != 2)
			return ERROR_IMAGE_FORMAT_ERROR;

		bytes_read += 4;
		cal_checksum += (uint8_t)count;

		/* skip checksum byte */
		count -= 1;

		if (record_type == 0) {
			/* S0 - starting record (optional) */
			int iValue;

			while (count-- > 0) {
				sscanf(&lpszLine[bytes_read], "%2x", &iValue);
				cal_checksum += (uint8_t)iValue;
				bytes_read += 2;
			}
		} else if (record_type >= 1 && record_type <= 3) {
			switch (record_type) {
				case 1:
					/* S1 - 16 bit address data record */
					sscanf(&lpszLine[bytes_read], "%4" SCNx32, &address);
					cal_checksum += (uint8_t)(address >> 8);
					cal_checksum += (uint8_t)address;
					bytes_read += 4;
					count -= 2;
					break;

				case 2:
					/* S2 - 24 bit address data record */
					sscanf(&lpszLine[bytes_read], "%6" SCNx32, &address);
					cal_checksum += (uint8_t)(address >> 16);
					cal_checksum += (uint8_t)(address >> 8);
					cal_checksum += (uint8_t)address;
					bytes_read += 6;
					count -= 3;
					break;

				case 3:
					/* S3 - 32 bit address data record */
					sscanf(&lpszLine[bytes_read], "%8" SCNx32, &address);
					cal_checksum += (uint8_t)(address >> 24);
					cal_checksum += (uint8_t)(address >> 16);
					cal_checksum += (uint8_t)(address >> 8);
					cal_checksum += (uint8_t)address;
					bytes_read += 8;
					count -= 4;
					break;

			}

			if (full_address != address) {
				/* we encountered a nonconsecutive location, create a new section,
				 * unless the current section has zero size, in which case this specifies
				 * the current section's base address
				 */
				if (section[image->num_sections].size != 0) {
					image->num_sections++;
					section[image->num_sections].size = 0x0;
					section[image->num_sections].flags = 0;
					section[image->num_sections].private =
						&mot->buffer[cooked_bytes];
				}
				section[image->num_sections].base_address = address;
				full_address = address;
			}

			while (count-- > 0) {
				unsigned value;
				sscanf(&lpszLine[bytes_read], "%2x", &value);
				mot->buffer[cooked_bytes] = (uint8_t)value;
				cal_checksum += (uint8_t)mot->buffer[cooked_bytes];
				bytes_read += 2;
				cooked_bytes += 1;
				section[image->num_sections].size += 1;
				full_address++;
			}
		} else if (record_type == 5) {
			/* S5 is the data count record, we ignore it */
			uint32_t dummy;

			while (count-- > 0) {
				sscanf(&lpszLine[bytes_read], "%2" SCNx32, &dummy);
				cal_checksum += (uint8_t)dummy;
				bytes_read += 2;
			}
		} else if (record_type >= 7 && record_type <= 9) {
			/* S7, S8, S9 - ending records for 32, 24 and 16bit */
			image->num_sections++;

			/* copy section information */
			image->sections = malloc(sizeof(struct imagesection) * image->num_sections);
			for (i = 0; i < image->num_sections; i++) {
				image->sections[i].private = section[i].private;
				image->sections[i].base_address = section[i].base_address;
				image->sections[i].size = section[i].size;
				image->sections[i].flags = section[i].flags;
			}

			return ERROR_OK;
		} else {
			LOG_ERROR("unhandled S19 record type: %i", (int)(record_type));
			return ERROR_IMAGE_FORMAT_ERROR;
		}

		/* account for checksum, will always be 0xFF */
		sscanf(&lpszLine[bytes_read], "%2" SCNx32, &checksum);
		cal_checksum += (uint8_t)checksum;

		if (cal_checksum != 0xFF) {
			/* checksum failed */
			LOG_ERROR("incorrect record checksum found in S19 file");
			return ERROR_IMAGE_CHECKSUM;
		}
	}

	LOG_ERROR("premature end of S19 file, no end-of-file record found");
	return ERROR_IMAGE_FORMAT_ERROR;
}

/**
 * Allocate memory dynamically instead of on the stack. This
 * is important w/embedded hosts.
 */
static int image_mot_buffer_complete(struct image *image)
{
	char *lpszLine = malloc(1023);
	if (lpszLine == NULL) {
		LOG_ERROR("Out of memory");
		return ERROR_FAIL;
	}
	struct imagesection *section = malloc(sizeof(struct imagesection) * IMAGE_MAX_SECTIONS);
	if (section == NULL) {
		free(lpszLine);
		LOG_ERROR("Out of memory");
		return ERROR_FAIL;
	}
	int retval;

	retval = image_mot_buffer_complete_inner(image, lpszLine, section);

	free(section);
	free(lpszLine);

	return retval;
}

int image_open(struct image *image, const char *url, const char *type_string)
{
	int retval = ERROR_OK;

	retval = identify_image_type(image, type_string, url);
	if (retval != ERROR_OK)
		return retval;

	if (image->type == IMAGE_BINARY) {
		struct image_binary *image_binary;

		image_binary = image->type_private = malloc(sizeof(struct image_binary));

		retval = fileio_open(&image_binary->fileio, url, FILEIO_READ, FILEIO_BINARY);
		if (retval != ERROR_OK)
			return retval;
		size_t filesize;
		retval = fileio_size(image_binary->fileio, &filesize);
		if (retval != ERROR_OK) {
			fileio_close(image_binary->fileio);
			return retval;
		}

		image->num_sections = 1;
		image->sections = malloc(sizeof(struct imagesection));
		image->sections[0].base_address = 0x0;
		image->sections[0].size = filesize;
		image->sections[0].flags = 0;
	} else if (image->type == IMAGE_IHEX) {
		struct image_ihex *image_ihex;

		image_ihex = image->type_private = malloc(sizeof(struct image_ihex));

		retval = fileio_open(&image_ihex->fileio, url, FILEIO_READ, FILEIO_TEXT);
		if (retval != ERROR_OK)
			return retval;

		retval = image_ihex_buffer_complete(image);
		if (retval != ERROR_OK) {
			LOG_ERROR(
				"failed buffering IHEX image, check server output for additional information");
			fileio_close(image_ihex->fileio);
			return retval;
		}
	} else if (image->type == IMAGE_ELF) {
		struct image_elf *image_elf;

		image_elf = image->type_private = malloc(sizeof(struct image_elf));

		retval = fileio_open(&image_elf->fileio, url, FILEIO_READ, FILEIO_BINARY);
		if (retval != ERROR_OK)
			return retval;

		retval = image_elf_read_headers(image);
		if (retval != ERROR_OK) {
			fileio_close(image_elf->fileio);
			return retval;
		}
	} else if (image->type == IMAGE_MEMORY) {
		struct target *target = get_target(url);

		if (target == NULL) {
			LOG_ERROR("target '%s' not defined", url);
			return ERROR_FAIL;
		}

		struct image_memory *image_memory;

		image->num_sections = 1;
		image->sections = malloc(sizeof(struct imagesection));
		image->sections[0].base_address = 0x0;
		image->sections[0].size = 0xffffffff;
		image->sections[0].flags = 0;

		image_memory = image->type_private = malloc(sizeof(struct image_memory));

		image_memory->target = target;
		image_memory->cache = NULL;
		image_memory->cache_address = 0x0;
	} else if (image->type == IMAGE_SRECORD) {
		struct image_mot *image_mot;

		image_mot = image->type_private = malloc(sizeof(struct image_mot));

		retval = fileio_open(&image_mot->fileio, url, FILEIO_READ, FILEIO_TEXT);
		if (retval != ERROR_OK)
			return retval;

		retval = image_mot_buffer_complete(image);
		if (retval != ERROR_OK) {
			LOG_ERROR(
				"failed buffering S19 image, check server output for additional information");
			fileio_close(image_mot->fileio);
			return retval;
		}
	} else if (image->type == IMAGE_BUILDER) {
		image->num_sections = 0;
		image->base_address_set = 0;
		image->sections = NULL;
		image->type_private = NULL;
	}

	if (image->base_address_set) {
		/* relocate */
		int section;
		for (section = 0; section < image->num_sections; section++)
			image->sections[section].base_address += image->base_address;
											/* we're done relocating. The two statements below are mainly
											* for documenation purposes: stop anyone from empirically
											* thinking they should use these values henceforth. */
		image->base_address = 0;
		image->base_address_set = 0;
	}

	return retval;
};

int image_read_section(struct image *image,
	int section,
	uint32_t offset,
	uint32_t size,
	uint8_t *buffer,
	size_t *size_read)
{
	int retval;

	/* don't read past the end of a section */
	if (offset + size > image->sections[section].size) {
		LOG_DEBUG(
			"read past end of section: 0x%8.8" PRIx32 " + 0x%8.8" PRIx32 " > 0x%8.8" PRIx32 "",
			offset,
			size,
			image->sections[section].size);
		return ERROR_COMMAND_SYNTAX_ERROR;
	}

	if (image->type == IMAGE_BINARY) {
		struct image_binary *image_binary = image->type_private;

		/* only one section in a plain binary */
		if (section != 0)
			return ERROR_COMMAND_SYNTAX_ERROR;

		/* seek to offset */
		retval = fileio_seek(image_binary->fileio, offset);
		if (retval != ERROR_OK)
			return retval;

		/* return requested bytes */
		retval = fileio_read(image_binary->fileio, size, buffer, size_read);
		if (retval != ERROR_OK)
			return retval;
	} else if (image->type == IMAGE_IHEX) {
		memcpy(buffer, (uint8_t *)image->sections[section].private + offset, size);
		*size_read = size;

		return ERROR_OK;
	} else if (image->type == IMAGE_ELF)
		return image_elf_read_section(image, section, offset, size, buffer, size_read);
	else if (image->type == IMAGE_MEMORY) {
		struct image_memory *image_memory = image->type_private;
		uint32_t address = image->sections[section].base_address + offset;

		*size_read = 0;

		while ((size - *size_read) > 0) {
			uint32_t size_in_cache;

			if (!image_memory->cache
				|| (address < image_memory->cache_address)
				|| (address >=
				(image_memory->cache_address + IMAGE_MEMORY_CACHE_SIZE))) {
				if (!image_memory->cache)
					image_memory->cache = malloc(IMAGE_MEMORY_CACHE_SIZE);

				if (target_read_buffer(image_memory->target, address &
					~(IMAGE_MEMORY_CACHE_SIZE - 1),
					IMAGE_MEMORY_CACHE_SIZE, image_memory->cache) != ERROR_OK) {
					free(image_memory->cache);
					image_memory->cache = NULL;
					return ERROR_IMAGE_TEMPORARILY_UNAVAILABLE;
				}
				image_memory->cache_address = address &
					~(IMAGE_MEMORY_CACHE_SIZE - 1);
			}

			size_in_cache =
				(image_memory->cache_address + IMAGE_MEMORY_CACHE_SIZE) - address;

			memcpy(buffer + *size_read,
				image_memory->cache + (address - image_memory->cache_address),
				(size_in_cache > size) ? size : size_in_cache
				);

			*size_read += (size_in_cache > size) ? size : size_in_cache;
			address += (size_in_cache > size) ? size : size_in_cache;
		}
	} else if (image->type == IMAGE_SRECORD) {
		memcpy(buffer, (uint8_t *)image->sections[section].private + offset, size);
		*size_read = size;

		return ERROR_OK;
	} else if (image->type == IMAGE_BUILDER) {
		memcpy(buffer, (uint8_t *)image->sections[section].private + offset, size);
		*size_read = size;

		return ERROR_OK;
	}

	return ERROR_OK;
}

int image_add_section(struct image *image, uint32_t base, uint32_t size, int flags, uint8_t const *data)
{
	struct imagesection *section;

	/* only image builder supports adding sections */
	if (image->type != IMAGE_BUILDER)
		return ERROR_COMMAND_SYNTAX_ERROR;

	/* see if there's a previous section */
	if (image->num_sections) {
		section = &image->sections[image->num_sections - 1];

		/* see if it's enough to extend the last section,
		 * adding data to previous sections or merging is not supported */
		if (((section->base_address + section->size) == base) &&
			(section->flags == flags)) {
			section->private = realloc(section->private, section->size + size);
			memcpy((uint8_t *)section->private + section->size, data, size);
			section->size += size;
			return ERROR_OK;
		}
	}

	/* allocate new section */
	image->num_sections++;
	image->sections =
		realloc(image->sections, sizeof(struct imagesection) * image->num_sections);
	section = &image->sections[image->num_sections - 1];
	section->base_address = base;
	section->size = size;
	section->flags = flags;
	section->private = malloc(sizeof(uint8_t) * size);
	memcpy((uint8_t *)section->private, data, size);

	return ERROR_OK;
}

void image_close(struct image *image)
{
	if (image->type == IMAGE_BINARY) {
		struct image_binary *image_binary = image->type_private;

		fileio_close(image_binary->fileio);
	} else if (image->type == IMAGE_IHEX) {
		struct image_ihex *image_ihex = image->type_private;

		fileio_close(image_ihex->fileio);

		if (image_ihex->buffer) {
			free(image_ihex->buffer);
			image_ihex->buffer = NULL;
		}
	} else if (image->type == IMAGE_ELF) {
		struct image_elf *image_elf = image->type_private;

		fileio_close(image_elf->fileio);

		if (image_elf->header) {
			free(image_elf->header);
			image_elf->header = NULL;
		}

		if (image_elf->segments) {
			free(image_elf->segments);
			image_elf->segments = NULL;
		}
	} else if (image->type == IMAGE_MEMORY) {
		struct image_memory *image_memory = image->type_private;

		if (image_memory->cache) {
			free(image_memory->cache);
			image_memory->cache = NULL;
		}
	} else if (image->type == IMAGE_SRECORD) {
		struct image_mot *image_mot = image->type_private;

		fileio_close(image_mot->fileio);

		if (image_mot->buffer) {
			free(image_mot->buffer);
			image_mot->buffer = NULL;
		}
	} else if (image->type == IMAGE_BUILDER) {
		int i;

		for (i = 0; i < image->num_sections; i++) {
			free(image->sections[i].private);
			image->sections[i].private = NULL;
		}
	}

	if (image->type_private) {
		free(image->type_private);
		image->type_private = NULL;
	}

	if (image->sections) {
		free(image->sections);
		image->sections = NULL;
	}
}

int image_calculate_checksum(uint8_t *buffer, uint32_t nbytes, uint32_t *checksum)
{
	uint32_t crc = 0xffffffff;
	LOG_DEBUG("Calculating checksum");

	static uint32_t crc32_table[256];

	static bool first_init;
	if (!first_init) {
		/* Initialize the CRC table and the decoding table.  */
		int i, j;
		unsigned int c;
		for (i = 0; i < 256; i++) {
			/* as per gdb */
			for (c = i << 24, j = 8; j > 0; --j)
				c = c & 0x80000000 ? (c << 1) ^ 0x04c11db7 : (c << 1);
			crc32_table[i] = c;
		}

		first_init = true;
	}

	while (nbytes > 0) {
		int run = nbytes;
		if (run > 32768)
			run = 32768;
		nbytes -= run;
		while (run--) {
			/* as per gdb */
			crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ *buffer++) & 255];
		}
		keep_alive();
	}

	LOG_DEBUG("Calculating checksum done");

	*checksum = crc;
	return ERROR_OK;
}