guid_part.c

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/*
 * Copyright (c) 2010 Jiri Svoboda
 * 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.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ipc/bd.h>
#include <async.h>
#include <as.h>
#include <fibril_synch.h>
#include <devmap.h>
#include <sys/types.h>
#include <sys/typefmt.h>
#include <inttypes.h>
#include <libblock.h>
#include <devmap.h>
#include <errno.h>
#include <bool.h>
#include <byteorder.h>
#include <assert.h>
#include <macros.h>
#include <task.h>

#include "gpt.h"

#define NAME "guid_part"

const uint8_t efi_signature[8] = {
        /* "EFI PART" in ASCII */
        0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54
};

typedef struct part {
        bool present;
        aoff64_t start_addr;
        aoff64_t length;
        devmap_handle_t dev;
        struct part *next;
} part_t;

static size_t block_size;

static devmap_handle_t indev_handle;

static part_t plist_head;

static int gpt_init(const char *dev_name);
static int gpt_read(void);
static part_t *gpt_part_new(void);
static void gpt_pte_to_part(const gpt_entry_t *pte, part_t *part);
static void gpt_connection(ipc_callid_t iid, ipc_call_t *icall);
static int gpt_bd_read(part_t *p, aoff64_t ba, size_t cnt, void *buf);
static int gpt_bd_write(part_t *p, aoff64_t ba, size_t cnt, const void *buf);
static int gpt_bsa_translate(part_t *p, aoff64_t ba, size_t cnt, aoff64_t *gba);

int main(int argc, char **argv)
{
        printf(NAME ": GUID partition table driver\n");

        if (argc != 2) {
                printf("Expected one argument (device name).\n");
                return -1;
        }

        if (gpt_init(argv[1]) != EOK)
                return -1;

        printf(NAME ": Accepting connections\n");
        task_retval(0);
        async_manager();

        /* Not reached */
        return 0;
}

static int gpt_init(const char *dev_name)
{
        int rc;
        int i;
        char *name;
        devmap_handle_t dev;
        uint64_t size_mb;
        part_t *part;

        rc = devmap_device_get_handle(dev_name, &indev_handle, 0);
        if (rc != EOK) {
                printf(NAME ": could not resolve device `%s'.\n", dev_name);
                return rc;
        }

        rc = block_init(indev_handle, 2048);
        if (rc != EOK)  {
                printf(NAME ": could not init libblock.\n");
                return rc;
        }

        /* Determine and verify block size. */

        rc = block_get_bsize(indev_handle, &block_size);
        if (rc != EOK) {
                printf(NAME ": error getting block size.\n");
                return rc;
        }

        if (block_size < 512 || (block_size % 512) != 0) {
                printf(NAME ": invalid block size %zu.\n", block_size);
                return ENOTSUP;
        }

        /* Read in partition records. */
        rc = gpt_read();
        if (rc != EOK)
                return rc;

        /* Register the driver with device mapper. */
        rc = devmap_driver_register(NAME, gpt_connection);
        if (rc != EOK) {
                printf(NAME ": Unable to register driver.\n");
                return rc;
        }

        /*
         * Create partition devices.
         */
        i = 0;
        part = plist_head.next;

        while (part != NULL) {
                /* Skip absent partitions. */
                if (!part->present) {
                        part = part->next;
                        ++i;
                        continue;
                }

                asprintf(&name, "%sp%d", dev_name, i);
                if (name == NULL)
                        return ENOMEM;

                rc = devmap_device_register(name, &dev);
                if (rc != EOK) {
                        printf(NAME ": Unable to register device %s.\n", name);
                        return rc;
                }

                size_mb = (part->length * block_size + 1024 * 1024 - 1)
                    / (1024 * 1024);
                printf(NAME ": Registered device %s: %" PRIu64 " blocks "
                    "%" PRIuOFF64 " MB.\n", name, part->length, size_mb);

                part->dev = dev;
                free(name);

                part = part->next;
                ++i;
        }

        return EOK;
}

static int gpt_read(void)
{
        int i, rc;
        gpt_header_t *gpt_hdr;
        gpt_entry_t *etable;
        uint64_t ba;
        uint32_t bcnt;
        uint32_t esize;
        uint32_t num_entries;
        uint32_t entry;
        part_t *prev, *p;

        gpt_hdr = malloc(block_size);
        if (gpt_hdr == NULL) {
                printf(NAME ": Failed allocating memory.\n");
                return ENOMEM;
        }

        rc = block_read_direct(indev_handle, GPT_HDR_BA, 1, gpt_hdr);
        if (rc != EOK) {
                printf(NAME ": Failed reading GPT header block.\n");
                return rc;
        }

        for (i = 0; i < 8; ++i) {
                if (gpt_hdr->efi_signature[i] != efi_signature[i]) {
                        printf(NAME ": Invalid GPT signature.\n");
                        return EINVAL;
                }
        }

        plist_head.next = NULL;
        prev = &plist_head;

        num_entries = uint32_t_le2host(gpt_hdr->num_entries);
        ba = uint64_t_le2host(gpt_hdr->entry_lba);
        esize = uint32_t_le2host(gpt_hdr->entry_size);
        bcnt = (num_entries / esize) + ((num_entries % esize != 0) ? 1 : 0);

        etable = malloc(num_entries * esize);
        if (etable == NULL) {
                free(gpt_hdr);
                printf(NAME ": Failed allocating memory.\n");
                return ENOMEM;
        }

        rc = block_read_direct(indev_handle, ba, bcnt, etable);
        if (rc != EOK) {
                printf(NAME ": Failed reading GPT entries.\n");
                return rc;
        }

        for (entry = 0; entry < num_entries; ++entry) {
                p = gpt_part_new();
                if (p == NULL)
                        return ENOMEM;

                gpt_pte_to_part(&etable[entry], p);
                prev->next = p;
                prev = p;
        }

        free(etable);

        return EOK;
}

static part_t *gpt_part_new(void)
{
        return malloc(sizeof(part_t));
}

static void gpt_pte_to_part(const gpt_entry_t *pte, part_t *part)
{
        uint64_t sa, len;
        int i;

        /* Partition spans addresses [start_lba, end_lba] (inclusive). */
        sa = uint64_t_le2host(pte->start_lba);
        len = uint64_t_le2host(pte->end_lba) + 1 - sa;

        part->start_addr = sa;
        part->length     = len;

        part->present = false;

        for (i = 0; i < 8; ++i) {
                if (pte->part_type[i] != 0x00)
                        part->present = true;
        }

        part->dev = 0;
        part->next = NULL;
}

static void gpt_connection(ipc_callid_t iid, ipc_call_t *icall)
{
        size_t comm_size;
        void *fs_va = NULL;
        ipc_callid_t callid;
        ipc_call_t call;
        sysarg_t method;
        devmap_handle_t dh;
        unsigned int flags;
        int retval;
        aoff64_t ba;
        size_t cnt;
        part_t *part;

        /* Get the device handle. */
        dh = IPC_GET_ARG1(*icall);

        /* 
         * Determine which partition device is the client connecting to.
         * A linear search is not terribly fast, but we only do this
         * once for each connection.
         */
        part = plist_head.next;
        while (part != NULL && part->dev != dh)
                part = part->next;

        if (part == NULL) {
                async_answer_0(iid, EINVAL);
                return;
        }

        assert(part->present == true);

        /* Answer the IPC_M_CONNECT_ME_TO call. */
        async_answer_0(iid, EOK);

        if (!async_share_out_receive(&callid, &comm_size, &flags)) {
                async_answer_0(callid, EHANGUP);
                return;
        }

        fs_va = as_get_mappable_page(comm_size);
        if (fs_va == NULL) {
                async_answer_0(callid, EHANGUP);
                return;
        }

        (void) async_share_out_finalize(callid, fs_va);

        while (1) {
                callid = async_get_call(&call);
                method = IPC_GET_IMETHOD(call);
                switch (method) {
                case IPC_M_PHONE_HUNGUP:
                        /* The other side has hung up. */
                        async_answer_0(callid, EOK);
                        return;
                case BD_READ_BLOCKS:
                        ba = MERGE_LOUP32(IPC_GET_ARG1(call),
                            IPC_GET_ARG2(call));
                        cnt = IPC_GET_ARG3(call);
                        if (cnt * block_size > comm_size) {
                                retval = ELIMIT;
                                break;
                        }
                        retval = gpt_bd_read(part, ba, cnt, fs_va);
                        break;
                case BD_WRITE_BLOCKS:
                        ba = MERGE_LOUP32(IPC_GET_ARG1(call),
                            IPC_GET_ARG2(call));
                        cnt = IPC_GET_ARG3(call);
                        if (cnt * block_size > comm_size) {
                                retval = ELIMIT;
                                break;
                        }
                        retval = gpt_bd_write(part, ba, cnt, fs_va);
                        break;
                case BD_GET_BLOCK_SIZE:
                        async_answer_1(callid, EOK, block_size);
                        continue;
                case BD_GET_NUM_BLOCKS:
                        async_answer_2(callid, EOK, LOWER32(part->length),
                            UPPER32(part->length));
                        continue;
                default:
                        retval = EINVAL;
                        break;
                }
                async_answer_0(callid, retval);
        }
}

static int gpt_bd_read(part_t *p, aoff64_t ba, size_t cnt, void *buf)
{
        aoff64_t gba;

        if (gpt_bsa_translate(p, ba, cnt, &gba) != EOK)
                return ELIMIT;

        return block_read_direct(indev_handle, gba, cnt, buf);
}

static int gpt_bd_write(part_t *p, aoff64_t ba, size_t cnt, const void *buf)
{
        aoff64_t gba;

        if (gpt_bsa_translate(p, ba, cnt, &gba) != EOK)
                return ELIMIT;

        return block_write_direct(indev_handle, gba, cnt, buf);
}

static int gpt_bsa_translate(part_t *p, aoff64_t ba, size_t cnt, aoff64_t *gba)
{
        if (ba + cnt > p->length)
                return ELIMIT;

        *gba = p->start_addr + ba;
        return EOK;
}

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