source: mainline/uspace/lib/gpt/libgpt.c@ cbd64057

/*
 * Copyright (c) 2011 Dominik Taborsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, 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 DAMAGE.
 */

/** @addtogroup libgpt
 * @{
 */
/** @file
 */

/* TODO:
 * This implementation only supports fixed size partition entries. Specification
 * requires otherwise, though. Use void * array and casting to achieve that.
 */

#include <checksum.h>
#include <errno.h>
#include <mem.h>

#include "libgpt.h"

/** Read GPT from specific device
 * @param       dev_handle      device to read GPT from
 * 
 * @return                              GPT record on success, NULL on error
 */
gpt_t * gpt_read_gpt_header(service_id_t dev_handle)
{
        int rc;
        size_t b_size;
        
        rc = block_get_bsize(dev_handle, &b_size);
        if (rc != EOK) {
                errno = rc;
                return NULL;
        }
        
        gpt_t * gpt = malloc(sizeof(gpt_t));
        if (gpt == NULL) {
                errno = ENOMEM;
                return NULL;
        }
        
        gpt->header_lba = malloc(b_size);// We might need only sizeof(gpt_header_t),
        if (gpt == NULL) {                              // but we should follow specs and have 
                free(gpt);                                      // zeroes through all the rest of the block
                errno = ENOMEM;
                return NULL;
        }
        
        
        rc = load_and_check_header(handle, GPT_HDR_BA, gpt->header_lba);
        if (rc == EBADCHECKSUM || rc == EINVAL) {
                aoff64_t n_blocks;
                rc = block_get_nblocks(dev_handle, &n_blocks);
                if (rc != EOK) {
                        errno = rc;
                        goto fail;
                }
                
                rc = load_and_check_header(handle, n_blocks - 1, gpt->header_lba);
                if (rc == EBADCHECKSUM || rc == EINVAL) {
                        errno = rc;
                        goto fail;
                }
        }
        
        return gpt;

fail:
        gpt_free_gpt(gpt);
        return NULL;
}

/** Write GPT header to device
 * @param header                GPT header to be written
 * @param dev_handle    device handle to write the data to
 * 
 * @return                              0 on success, libblock error code otherwise
 */
int gpt_write_gpt_header(gpt_t * header, service_id_t dev_handle)
{
        int rc;
        size_t b_size;
        
        header->raw_data->header_crc32 = 0;
        header->raw_data->header_crc32 = compute_crc32(header, header->header_size);
        
        rc = block_get_bsize(dev_handle, &b_size);
        if (rc != EOK)
                return rc;
        
        rc = block_init(EXCHANGE_ATOMIC, dev_handle, b_size);
        if (rc != EOK)
                return rc;
        
        /* Write to main GPT header location */
        rc = block_write_direct(dev_handle, GPT_HDR_BA, GPT_HDR_BS, header->raw_data);
        if (rc != EOK)
                block_fini(dev_handle);
                return rc;
        
        aoff64_t n_blocks;
        rc = block_get_nblocks(dev_handle, &n_blocks);
        if (rc != EOK)
                return rc;
        
        /* Write to backup GPT header location */
        rc = block_write_direct(dev_handle, n_blocks - 1, GPT_HDR_BS, header->raw_data);
        block_fini(dev_handle);
        if (rc != EOK)
                return rc;
                
        return 0;
}

/** Parse partitions from GPT
 * @param gpt   GPT to be parsed
 * 
 * @return              partition linked list pointer or NULL on error
 *                              error code is stored in errno
 */
gpt_parts_t * gpt_read_partitions(gpt_t * gpt)
{
        int i;
        gpt_parts_t * res;
        uint32_t num_ent = uint32_t_le2host(gpt->header.num_entries);
        uint32_t ent_size = uint32_t_le2host(gpt->header.entry_size);
        uint64_t ent_lba = uint64_t_le2host(gpt->header.entry_lba);
        
        res = alloc_part_array(num_ent);
        if (res == NULL) {
                //errno = ENOMEM; // already set in alloc_part_array()
                return NULL;
        }
        
        /* We can limit comm_size like this:
         *  - we don't need more bytes
         *  - the size of GPT partition entry can be different to 128 bytes */
        rc = block_init(EXCHANGE_SERIALIZE, dev_handle, sizeof(gpt_entry_t));
        if (rc != EOK) {
                gpt_free_partitions(res);
                errno = rc;
                return NULL;
        }
        
        size_t block_size;
        rc = block_get_bsize(gpt->device, &block_size);
        if (rc != EOK) {
                gpt_free_partitions(res);
                errno = rc;
                return NULL;
        }
        
        //size_t bufpos = 0;
        //size_t buflen = 0;
        aoff64_t pos = ent_lba * block_size;
        
        /* Now we read just sizeof(gpt_entry_t) bytes for each entry from the device.
         * Hopefully, this does not bypass cache (no mention in libblock.c),
         * and also allows us to have variable partition entry size (but we
         * will always read just sizeof(gpt_entry_t) bytes - hopefully they
         * don't break backward compatibility) */
        for (i = 0; i < num_ent; ++i) {
                //FIXME: this does bypass cache...
                rc = block_read_bytes_direct(gpt->device, pos, sizeof(gpt_entry_t), res->part_array + i);
                //FIXME: but seqread() is just too complex...
                //rc = block_seqread(gpt->device, &bufpos, &buflen, &pos, res->part_array[i], sizeof(gpt_entry_t));
                pos += ent_size;
                
                if (rc != EOK) {
                        gpt_free_partitions(res);
                        errno = rc;
                        return NULL;
                }
        }
        
        uint32_t crc = compute_crc32(res->part_array, res->num_ent * sizeof(gpt_entry_t));
        
        if(gpt->raw_data.pe_array_crc32 != crc)
        {
                gpt_free_partitions(res);
                errno = EBADCHECKSUM;
                return NULL;
        }
        
        return res;
}

/** Write GPT and partitions to device
 * @param parts                 partition list to be written
 * @param mbr                   MBR to be written with 'parts' partitions
 * @param dev_handle    device to write the data to
 * 
 * @return                              returns EOK on succes, specific error code otherwise
 */
int gpt_write_partitions(gpt_parts_t * parts, gpt_t * header, service_id_t dev_handle)
{
        int i;
        size_t b_size;
        
        header->raw_data->pe_array_crc32 = compute_crc32(parts->part_array, parts->num_ent * header->raw_data->entry_size);
        
        rc = block_get_bsize(dev_handle, &b_size);
        if (rc != EOK)
                return rc;
        
        rc = block_init(EXCHANGE_ATOMIC, dev_handle, b_size);
        if (rc != EOK)
                return rc;
        
        /* Write to main GPT partition array location */
        rc = block_write_direct(dev_handle, uint64_t_le2host(header->entry_lba), 
                        nearest_larger_int((uint64_t_le2host(header->raw_data->entry_size) * parts->num_ent) / b_size), 
                        parts->part_array);
        if (rc != EOK)
                block_fini(dev_handle);
                return rc;
        
        aoff64_t n_blocks;
        rc = block_get_nblocks(dev_handle, &n_blocks);
        if (rc != EOK)
                return rc;
        
        /* Write to backup GPT partition array location */
        //rc = block_write_direct(dev_handle, n_blocks - 1, GPT_HDR_BS, header->raw_data);
        block_fini(dev_handle);
        if (rc != EOK)
                return rc;
        
        
        gpt_write_gpt_header(header, dev_handle);
        
        return 0;
        
}

/** free() GPT header including gpt->header_lba */
void gpt_free_gpt(gpt_t * gpt)
{
        free(gpt->header_lba);
        free(gpt);
}

/** Free partition list
 * 
 * @param parts         partition list to be freed
 */
void gpt_free_partitions(gpt_parts_t * parts)
{
        free(parts->part_array);
        free(parts);
}

/** Set partition type
 * @param p                     partition to be set
 * @param type          partition type to set
 *                                      - see gpt_ptypes to choose from
 * 
 */
void gpt_set_part_type(g_part_t * p, int type)
{
        /* Beware: first 3 blocks are byteswapped! */
        p->raw_data.part_type[3] = gpt_ptypes[type][0];
        p->raw_data.part_type[2] = gpt_ptypes[type][1];
        p->raw_data.part_type[1] = gpt_ptypes[type][2];
        p->raw_data.part_type[0] = gpt_ptypes[type][3];
        
        p->raw_data.part_type[5] = gpt_ptypes[type][4];
        p->raw_data.part_type[4] = gpt_ptypes[type][5];
        
        p->raw_data.part_type[7] = gpt_ptypes[type][6];
        p->raw_data.part_type[6] = gpt_ptypes[type][7];
        
        p->raw_data.part_type[8] = gpt_ptypes[type][8];
        p->raw_data.part_type[9] = gpt_ptypes[type][9];
        p->raw_data.part_type[10] = gpt_ptypes[type][10];
        p->raw_data.part_type[11] = gpt_ptypes[type][11];
        p->raw_data.part_type[12] = gpt_ptypes[type][12];
        p->raw_data.part_type[13] = gpt_ptypes[type][13];
        p->raw_data.part_type[14] = gpt_ptypes[type][14];
        p->raw_data.part_type[15] = gpt_ptypes[type][15];
}

/** Copy partition name */
void gpt_set_part_name(gpt_entry_t * p, char_t name[], size_t length)
{
        memcpy(p->part_name, name, length);
}

// Internal functions follow //

static int load_and_check_header(service_id_t handle, aoff64_t addr, gpt_t * header)
{
        rc = block_init(EXCHANGE_ATOMIC, handle, b_size);
        if (rc != EOK)
                return rc;
        
        rc = block_read_direct(handle, addr, GPT_HDR_BS, gpt->header_lba);
        block_fini(handle);
        if (rc != EOK)
                return rc;
        
        
        int i;
        /* Check the EFI signature */
        for (i = 0; i < 8; ++i) {
                if (gpt->header_lba.efi_signature[i] != efi_signature[i])
                        return EINVAL;
        }
        
        /* Check the CRC32 of the header */
        uint32_t crc = gpt->header_lba->header_crc32;
        gpt->header_lba->header_crc32 = 0;
        if (crc != compute_crc32(gpt->header_lba, gpt->header_lba->header_size))
                return EBADCHECKSUM;
        else
                gpt->header_lba->header_crc32 = crc;
        
        /* Check for zeroes in the rest of the block */
        for (i = sizeof(gpt_header_t); i < b_size; ++i) {
                if (((uint8_t *) gpt->header_lba)[i] != 0)
                        goto EINVAL;
        }
        
        gpt->device = dev_handle;
        //gpt->partitions = NULL;
        
        return EOK;
}

static gpt_parts_t * alloc_part_array(uint32_t num)
{
        gpt_parts_t * res = malloc(sizeof(gpt_parts_t));
        if (res == NULL) {
                errno = ENOMEM;
                return NULL;
        }
        
        uint32_t size = num > GPT_BASE_PART_NUM ? num : GPT_BASE_PART_NUM;
        res->part_array = malloc(size * sizeof(gpt_entry_t));
        if (res.part_array == NULL) {
                free(res);
                errno = ENOMEM;
                return NULL;
        }
        
        res->num_ent = num;
        res->arr_size = size;
        
        return res;
}

static int extend_part_array(gpt_parts_t * p)
{
        unsigned int nsize = p->arr_size * 2;
        gpt_entry_t * tmp = malloc(nsize * sizeof(gpt_entry_t));
        if(tmp == NULL) {
                errno = ENOMEM;
                return -1;
        }
        
        memcpy(tmp, p->part_array, p->num_ent);
        free(p->part_array);
        p->part_array = tmp;
        p->arr_size = nsize;
        
        return 0;
}

static int reduce_part_array(gpt_parts_t * p)
{
        if(p->arr_size > GPT_MIN_PART_NUM) {
                unsigned int nsize = p->arr_size / 2;
                gpt_entry_t * tmp = malloc(nsize * sizeof(gpt_entry_t));
                if(tmp == NULL) {
                        errno = ENOMEM;
                        return -1;
                }
                
                memcpy(tmp, p->part_array, p->num_ent < nsize ? p->num_ent : nsize);
                free(p->part_array);
                p->part_array = tmp;
                p->arr_size = nsize;
        }
        
        return 0;
}

//FIXME: replace this with a library call, if it exists
static long long nearest_larger_int(double a)
{
        if ((long long) a == a) {
                return (long long) a;
        }
        
        return ((long long) a) + 1;
}