/* * partitioned_file.c, read and write binary file "partitions" described by FMAP * * Copyright (C) 2015 Google, Inc. * * 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; version 2 of the License. * * 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. */ #include "partitioned_file.h" #include "cbfs_sections.h" #include <assert.h> #include <stdlib.h> #include <string.h> struct partitioned_file { struct fmap *fmap; struct buffer buffer; FILE *stream; }; static bool fill_ones_through(struct partitioned_file *file) { assert(file); memset(file->buffer.data, 0xff, file->buffer.size); return partitioned_file_write_region(file, &file->buffer); } static unsigned count_selected_fmap_entries(const struct fmap *fmap, partitioned_file_fmap_selector_t callback, const void *arg) { assert(fmap); assert(callback); unsigned count = 0; for (unsigned i = 0; i < fmap->nareas; ++i) { if (callback(fmap->areas + i, arg)) ++count; } return count; } static partitioned_file_t *reopen_flat_file(const char *filename, bool write_access) { assert(filename); struct partitioned_file *file = calloc(1, sizeof(*file)); const char *access_mode; if (!file) { ERROR("Failed to allocate partitioned file structure\n"); return NULL; } if (buffer_from_file(&file->buffer, filename)) { free(file); return NULL; } access_mode = write_access ? "rb+" : "rb"; file->stream = fopen(filename, access_mode); if (!file->stream) { perror(filename); partitioned_file_close(file); return NULL; } return file; } partitioned_file_t *partitioned_file_create_flat(const char *filename, size_t image_size) { assert(filename); struct partitioned_file *file = calloc(1, sizeof(*file)); if (!file) { ERROR("Failed to allocate partitioned file structure\n"); return NULL; } file->stream = fopen(filename, "wb"); if (!file->stream) { perror(filename); free(file); return NULL; } if (buffer_create(&file->buffer, image_size, filename)) { partitioned_file_close(file); return NULL; } if (!fill_ones_through(file)) { partitioned_file_close(file); return NULL; } return file; } partitioned_file_t *partitioned_file_create(const char *filename, struct buffer *flashmap) { assert(filename); assert(flashmap); assert(flashmap->data); if (fmap_find((const uint8_t *)flashmap->data, flashmap->size) != 0) { ERROR("Attempted to create a partitioned image out of something that isn't an FMAP\n"); return NULL; } struct fmap *bootstrap_fmap = (struct fmap *)flashmap->data; const struct fmap_area *fmap_area = fmap_find_area(bootstrap_fmap, SECTION_NAME_FMAP); if (!fmap_area) { ERROR("Provided FMAP missing '%s' region\n", SECTION_NAME_FMAP); return NULL; } if (count_selected_fmap_entries(bootstrap_fmap, partitioned_file_fmap_select_children_of, fmap_area)) { ERROR("Provided FMAP's '%s' region contains other regions\n", SECTION_NAME_FMAP); return NULL; } int fmap_len = fmap_size(bootstrap_fmap); if (fmap_len < 0) { ERROR("Unable to determine size of provided FMAP\n"); return NULL; } assert((size_t)fmap_len <= flashmap->size); if ((uint32_t)fmap_len > fmap_area->size) { ERROR("Provided FMAP's '%s' region needs to be at least %d bytes\n", SECTION_NAME_FMAP, fmap_len); return NULL; } partitioned_file_t *file = partitioned_file_create_flat(filename, bootstrap_fmap->size); if (!file) return NULL; struct buffer fmap_region; buffer_splice(&fmap_region, &file->buffer, fmap_area->offset, fmap_area->size); memcpy(fmap_region.data, bootstrap_fmap, fmap_len); if (!partitioned_file_write_region(file, &fmap_region)) { partitioned_file_close(file); return NULL; } file->fmap = (struct fmap *)(file->buffer.data + fmap_area->offset); return file; } partitioned_file_t *partitioned_file_reopen(const char *filename, bool write_access) { assert(filename); partitioned_file_t *file = reopen_flat_file(filename, write_access); if (!file) return NULL; long fmap_region_offset = fmap_find((const uint8_t *)file->buffer.data, file->buffer.size); if (fmap_region_offset < 0) { INFO("Opening image as a flat file because it doesn't contain any FMAP\n"); return file; } file->fmap = (struct fmap *)(file->buffer.data + fmap_region_offset); if (file->fmap->size > file->buffer.size) { int fmap_region_size = fmap_size(file->fmap); ERROR("FMAP records image size as %u, but file is only %zu bytes%s\n", file->fmap->size, file->buffer.size, fmap_region_offset == 0 && (signed)file->buffer.size == fmap_region_size ? " (is it really an image, or *just* an FMAP?)" : " (did something truncate this file?)"); partitioned_file_close(file); return NULL; } const struct fmap_area *fmap_fmap_entry = fmap_find_area(file->fmap, SECTION_NAME_FMAP); if ((long)fmap_fmap_entry->offset != fmap_region_offset) { ERROR("FMAP's '%s' section doesn't point back to FMAP start (did something corrupt this file?)\n", SECTION_NAME_FMAP); partitioned_file_close(file); return NULL; } return file; } bool partitioned_file_write_region(partitioned_file_t *file, const struct buffer *buffer) { assert(file); assert(file->stream); assert(buffer); assert(buffer->data); if (buffer->data - buffer->offset != file->buffer.data) { ERROR("Attempted to write a partition buffer back to a different file than it came from\n"); return false; } if (buffer->offset + buffer->size > file->buffer.size) { ERROR("Attempted to write data off the end of image file\n"); return false; } if (fseek(file->stream, buffer->offset, SEEK_SET)) { ERROR("Failed to seek within image file\n"); return false; } if (!fwrite(buffer->data, buffer->size, 1, file->stream)) { ERROR("Failed to write to image file\n"); return false; } return true; } bool partitioned_file_read_region(struct buffer *dest, const partitioned_file_t *file, const char *region) { assert(dest); assert(file); assert(file->buffer.data); assert(region); if (file->fmap) { const struct fmap_area *area = fmap_find_area(file->fmap, region); if (!area) { ERROR("Image is missing '%s' region\n", region); return false; } if (area->offset + area->size > file->buffer.size) { ERROR("Region '%s' runs off the end of the image file\n", region); return false; } buffer_splice(dest, &file->buffer, area->offset, area->size); } else { if (strcmp(region, SECTION_NAME_PRIMARY_CBFS) != 0) { ERROR("This is a legacy image that contains only a CBFS\n"); return false; } buffer_clone(dest, &file->buffer); } return true; } void partitioned_file_close(partitioned_file_t *file) { if (!file) return; file->fmap = NULL; buffer_delete(&file->buffer); if (file->stream) { fclose(file->stream); file->stream = NULL; } free(file); } bool partitioned_file_is_partitioned(const partitioned_file_t *file) { return partitioned_file_get_fmap(file) != NULL; } size_t partitioned_file_total_size(const partitioned_file_t *file) { assert(file); return file->buffer.size; } bool partitioned_file_region_check_magic(const partitioned_file_t *file, const char *region, const char *magic, size_t magic_len) { struct buffer area; return partitioned_file_read_region(&area, file, region) && buffer_check_magic(&area, magic, magic_len); } bool partitioned_file_region_contains_nested(const partitioned_file_t *file, const char *region) { assert(file); assert(region); if (!file->fmap) return false; const struct fmap_area *area = fmap_find_area(file->fmap, region); return area && partitioned_file_fmap_count(file, partitioned_file_fmap_select_children_of, area); } const struct fmap *partitioned_file_get_fmap(const partitioned_file_t *file) { assert(file); return file->fmap; } unsigned partitioned_file_fmap_count(const partitioned_file_t *file, partitioned_file_fmap_selector_t callback, const void *arg) { assert(file); assert(callback); if (!file->fmap) return 0; return count_selected_fmap_entries(file->fmap, callback, arg); } static bool select_all(unused const struct fmap_area *area, unused const void *arg) { return true; } const partitioned_file_fmap_selector_t partitioned_file_fmap_select_all = select_all; static bool select_children_of(const struct fmap_area *child, const void *arg) { assert(child); assert(arg); const struct fmap_area *parent = (const struct fmap_area *)arg; if (child == arg || (child->offset == parent->offset && child->size == parent->size)) return false; return child->offset >= parent->offset && child->offset + child->size <= parent->offset + parent->size; } const partitioned_file_fmap_selector_t partitioned_file_fmap_select_children_of = select_children_of; static bool select_parents_of(const struct fmap_area *parent, const void *arg) { return select_children_of((const struct fmap_area *)arg, parent); } const partitioned_file_fmap_selector_t partitioned_file_fmap_select_parents_of = select_parents_of;