path: root/kernel/power/tuxonice_bio_signature.c

/*
 * kernel/power/tuxonice_bio_signature.c
 *
 * Copyright (C) 2004-2015 Nigel Cunningham (nigel at nigelcunningham com au)
 *
 * Distributed under GPLv2.
 *
 */

#include <linux/fs_uuid.h>

#include "tuxonice.h"
#include "tuxonice_sysfs.h"
#include "tuxonice_modules.h"
#include "tuxonice_prepare_image.h"
#include "tuxonice_bio.h"
#include "tuxonice_ui.h"
#include "tuxonice_alloc.h"
#include "tuxonice_io.h"
#include "tuxonice_builtin.h"
#include "tuxonice_bio_internal.h"

struct sig_data *toi_sig_data;

/* Struct of swap header pages */

struct old_sig_data {
        dev_t device;
        unsigned long sector;
        int resume_attempted;
        int orig_sig_type;
};

union diskpage {
        union swap_header swh;        /* swh.magic is the only member used */
        struct sig_data sig_data;
        struct old_sig_data old_sig_data;
};

union p_diskpage {
        union diskpage *pointer;
        char *ptr;
        unsigned long address;
};

char *toi_cur_sig_page;
char *toi_orig_sig_page;
int have_image;
int have_old_image;

int get_signature_page(void)
{
        if (!toi_cur_sig_page) {
                toi_message(TOI_IO, TOI_VERBOSE, 0,
                                "Allocating current signature page.");
                toi_cur_sig_page = (char *) toi_get_zeroed_page(38,
                        TOI_ATOMIC_GFP);
                if (!toi_cur_sig_page) {
                        printk(KERN_ERR "Failed to allocate memory for the "
                                "current image signature.\n");
                        return -ENOMEM;
                }

                toi_sig_data = (struct sig_data *) toi_cur_sig_page;
        }

        toi_message(TOI_IO, TOI_VERBOSE, 0, "Reading signature from dev %lx,"
                        " sector %d.",
                        resume_block_device->bd_dev, resume_firstblock);

        return toi_bio_ops.bdev_page_io(READ, resume_block_device,
                resume_firstblock, virt_to_page(toi_cur_sig_page));
}

void forget_signature_page(void)
{
        if (toi_cur_sig_page) {
                toi_sig_data = NULL;
                toi_message(TOI_IO, TOI_VERBOSE, 0, "Freeing toi_cur_sig_page"
                                " (%p).", toi_cur_sig_page);
                toi_free_page(38, (unsigned long) toi_cur_sig_page);
                toi_cur_sig_page = NULL;
        }

        if (toi_orig_sig_page) {
                toi_message(TOI_IO, TOI_VERBOSE, 0, "Freeing toi_orig_sig_page"
                                " (%p).", toi_orig_sig_page);
                toi_free_page(38, (unsigned long) toi_orig_sig_page);
                toi_orig_sig_page = NULL;
        }
}

/*
 * We need to ensure we use the signature page that's currently on disk,
 * so as to not remove the image header. Post-atomic-restore, the orig sig
 * page will be empty, so we can use that as our method of knowing that we
 * need to load the on-disk signature and not use the non-image sig in
 * memory. (We're going to powerdown after writing the change, so it's safe.
 */
int toi_bio_mark_resume_attempted(int flag)
{
        toi_message(TOI_IO, TOI_VERBOSE, 0, "Make resume attempted = %d.",
                        flag);
        if (!toi_orig_sig_page) {
                forget_signature_page();
                get_signature_page();
        }
        toi_sig_data->resumed_before = flag;
        return toi_bio_ops.bdev_page_io(WRITE, resume_block_device,
                resume_firstblock, virt_to_page(toi_cur_sig_page));
}

int toi_bio_mark_have_image(void)
{
        int result = 0;
        char buf[32];
        struct fs_info *fs_info;

        toi_message(TOI_IO, TOI_VERBOSE, 0, "Recording that an image exists.");
        memcpy(toi_sig_data->sig, tuxonice_signature,
                        sizeof(tuxonice_signature));
        toi_sig_data->have_image = 1;
        toi_sig_data->resumed_before = 0;
        toi_sig_data->header_dev_t = get_header_dev_t();
        toi_sig_data->have_uuid = 0;

        fs_info = fs_info_from_block_dev(get_header_bdev());
        if (fs_info && !IS_ERR(fs_info)) {
                memcpy(toi_sig_data->header_uuid, &fs_info->uuid, 16);
                free_fs_info(fs_info);
        } else
                result = (int) PTR_ERR(fs_info);

        if (!result) {
                toi_message(TOI_IO, TOI_VERBOSE, 0, "Got uuid for dev_t %s.",
                                format_dev_t(buf, get_header_dev_t()));
                toi_sig_data->have_uuid = 1;
        } else
                toi_message(TOI_IO, TOI_VERBOSE, 0, "Could not get uuid for "
                                "dev_t %s.",
                                format_dev_t(buf, get_header_dev_t()));

        toi_sig_data->first_header_block = get_headerblock();
        have_image = 1;
        toi_message(TOI_IO, TOI_VERBOSE, 0, "header dev_t is %x. First block "
                        "is %d.", toi_sig_data->header_dev_t,
                        toi_sig_data->first_header_block);

        memcpy(toi_sig_data->sig2, tuxonice_signature,
                        sizeof(tuxonice_signature));
        toi_sig_data->header_version = TOI_HEADER_VERSION;

        return toi_bio_ops.bdev_page_io(WRITE, resume_block_device,
                resume_firstblock, virt_to_page(toi_cur_sig_page));
}

int remove_old_signature(void)
{
        union p_diskpage swap_header_page = (union p_diskpage) toi_cur_sig_page;
        char *orig_sig;
        char *header_start = (char *) toi_get_zeroed_page(38, TOI_ATOMIC_GFP);
        int result;
        struct block_device *header_bdev;
        struct old_sig_data *old_sig_data =
                &swap_header_page.pointer->old_sig_data;

        header_bdev = toi_open_bdev(NULL, old_sig_data->device, 1);
        result = toi_bio_ops.bdev_page_io(READ, header_bdev,
                        old_sig_data->sector, virt_to_page(header_start));

        if (result)
                goto out;

        /*
         * TODO: Get the original contents of the first bytes of the swap
         * header page.
         */
        if (!old_sig_data->orig_sig_type)
                orig_sig = "SWAP-SPACE";
        else
                orig_sig = "SWAPSPACE2";

        memcpy(swap_header_page.pointer->swh.magic.magic, orig_sig, 10);
        memcpy(swap_header_page.ptr, header_start, 10);

        result = toi_bio_ops.bdev_page_io(WRITE, resume_block_device,
                resume_firstblock, virt_to_page(swap_header_page.ptr));

out:
        toi_close_bdev(header_bdev);
        have_old_image = 0;
        toi_free_page(38, (unsigned long) header_start);
        return result;
}

/*
 * toi_bio_restore_original_signature - restore the original signature
 *
 * At boot time (aborting pre atomic-restore), toi_orig_sig_page gets used.
 * It will have the original signature page contents, stored in the image
 * header. Post atomic-restore, we use :toi_cur_sig_page, which will contain
 * the contents that were loaded when we started the cycle.
 */
int toi_bio_restore_original_signature(void)
{
        char *use = toi_orig_sig_page ? toi_orig_sig_page : toi_cur_sig_page;

        if (have_old_image)
                return remove_old_signature();

        if (!use) {
                printk("toi_bio_restore_original_signature: No signature "
                                "page loaded.\n");
                return 0;
        }

        toi_message(TOI_IO, TOI_VERBOSE, 0, "Recording that no image exists.");
        have_image = 0;
        toi_sig_data->have_image = 0;
        return toi_bio_ops.bdev_page_io(WRITE, resume_block_device,
                resume_firstblock, virt_to_page(use));
}

/*
 * check_for_signature - See whether we have an image.
 *
 * Returns 0 if no image, 1 if there is one, -1 if indeterminate.
 */
int toi_check_for_signature(void)
{
        union p_diskpage swap_header_page;
        int type;
        const char *normal_sigs[] = {"SWAP-SPACE", "SWAPSPACE2" };
        const char *swsusp_sigs[] = {"S1SUSP", "S2SUSP", "S1SUSPEND" };
        char *swap_header;

        if (!toi_cur_sig_page) {
                int result = get_signature_page();

                if (result)
                        return result;
        }

        /*
         * Start by looking for the binary header.
         */
        if (!memcmp(tuxonice_signature, toi_cur_sig_page,
                                sizeof(tuxonice_signature))) {
                have_image = toi_sig_data->have_image;
                toi_message(TOI_IO, TOI_VERBOSE, 0, "Have binary signature. "
                                "Have image is %d.", have_image);
                if (have_image)
                        toi_message(TOI_IO, TOI_VERBOSE, 0, "header dev_t is "
                                        "%x. First block is %d.",
                                        toi_sig_data->header_dev_t,
                                        toi_sig_data->first_header_block);
                return toi_sig_data->have_image;
        }

        /*
         * Failing that, try old file allocator headers.
         */

        if (!memcmp(HaveImage, toi_cur_sig_page, strlen(HaveImage))) {
                have_image = 1;
                return 1;
        }

        have_image = 0;

        if (!memcmp(NoImage, toi_cur_sig_page, strlen(NoImage)))
                return 0;

        /*
         * Nope? How about swap?
         */
        swap_header_page = (union p_diskpage) toi_cur_sig_page;
        swap_header = swap_header_page.pointer->swh.magic.magic;

        /* Normal swapspace? */
        for (type = 0; type < 2; type++)
                if (!memcmp(normal_sigs[type], swap_header,
                                        strlen(normal_sigs[type])))
                        return 0;

        /* Swsusp or uswsusp? */
        for (type = 0; type < 3; type++)
                if (!memcmp(swsusp_sigs[type], swap_header,
                                        strlen(swsusp_sigs[type])))
                        return 2;

        /* Old TuxOnIce version? */
        if (!memcmp(tuxonice_signature, swap_header,
                                sizeof(tuxonice_signature) - 1)) {
                toi_message(TOI_IO, TOI_VERBOSE, 0, "Found old TuxOnIce "
                                "signature.");
                have_old_image = 1;
                return 3;
        }

        return -1;
}

/*
 * Image_exists
 *
 * Returns -1 if don't know, otherwise 0 (no) or 1 (yes).
 */
int toi_bio_image_exists(int quiet)
{
        int result;
        char *msg = NULL;

        toi_message(TOI_IO, TOI_VERBOSE, 0, "toi_bio_image_exists.");

        if (!resume_dev_t) {
                if (!quiet)
                        printk(KERN_INFO "Not even trying to read header "
                                "because resume_dev_t is not set.\n");
                return -1;
        }

        if (open_resume_dev_t(0, quiet))
                return -1;

        result = toi_check_for_signature();

        clear_toi_state(TOI_RESUMED_BEFORE);
        if (toi_sig_data->resumed_before)
                set_toi_state(TOI_RESUMED_BEFORE);

        if (quiet || result == -ENOMEM)
                return result;

        if (result == -1)
                msg = "TuxOnIce: Unable to find a signature."
                                " Could you have moved a swap file?\n";
        else if (!result)
                msg = "TuxOnIce: No image found.\n";
        else if (result == 1)
                msg = "TuxOnIce: Image found.\n";
        else if (result == 2)
                msg = "TuxOnIce: uswsusp or swsusp image found.\n";
        else if (result == 3)
                msg = "TuxOnIce: Old implementation's signature found.\n";

        printk(KERN_INFO "%s", msg);

        return result;
}

int toi_bio_scan_for_image(int quiet)
{
        struct block_device *bdev;
        char default_name[255] = "";

        if (!quiet)
                printk(KERN_DEBUG "Scanning swap devices for TuxOnIce "
                                "signature...\n");
        for (bdev = next_bdev_of_type(NULL, "swap"); bdev;
                                bdev = next_bdev_of_type(bdev, "swap")) {
                int result;
                char name[255] = "";
                sprintf(name, "%u:%u", MAJOR(bdev->bd_dev),
                                MINOR(bdev->bd_dev));
                if (!quiet)
                        printk(KERN_DEBUG "- Trying %s.\n", name);
                resume_block_device = bdev;
                resume_dev_t = bdev->bd_dev;

                result = toi_check_for_signature();

                resume_block_device = NULL;
                resume_dev_t = MKDEV(0, 0);

                if (!default_name[0])
                        strcpy(default_name, name);

                if (result == 1) {
                        /* Got one! */
                        strcpy(resume_file, name);
                        next_bdev_of_type(bdev, NULL);
                        if (!quiet)
                                printk(KERN_DEBUG " ==> Image found on %s.\n",
                                                resume_file);
                        return 1;
                }
                forget_signature_page();
        }

        if (!quiet)
                printk(KERN_DEBUG "TuxOnIce scan: No image found.\n");
        strcpy(resume_file, default_name);
        return 0;
}

int toi_bio_get_header_version(void)
{
        return (memcmp(toi_sig_data->sig2, tuxonice_signature,
                                sizeof(tuxonice_signature))) ?
                0 : toi_sig_data->header_version;

}