block.c.svn-base

我们自己开发的一个OSEK操作系统！不知道可不可以？

/*
 * QEMU System Emulator block driver
 *
 * Copyright (c) 2003 Fabrice Bellard
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "qemu-common.h"
#ifndef QEMU_IMG
#include "console.h"
#endif
#include "block_int.h"

#ifdef _BSD
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/queue.h>
#include <sys/disk.h>
#endif

#define SECTOR_BITS 9
#define SECTOR_SIZE (1 << SECTOR_BITS)

typedef struct BlockDriverAIOCBSync {
    BlockDriverAIOCB common;
    QEMUBH *bh;
    int ret;
} BlockDriverAIOCBSync;

static BlockDriverAIOCB *bdrv_aio_read_em(BlockDriverState *bs,
        int64_t sector_num, uint8_t *buf, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque);
static BlockDriverAIOCB *bdrv_aio_write_em(BlockDriverState *bs,
        int64_t sector_num, const uint8_t *buf, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque);
static void bdrv_aio_cancel_em(BlockDriverAIOCB *acb);
static int bdrv_read_em(BlockDriverState *bs, int64_t sector_num,
                        uint8_t *buf, int nb_sectors);
static int bdrv_write_em(BlockDriverState *bs, int64_t sector_num,
                         const uint8_t *buf, int nb_sectors);

BlockDriverState *bdrv_first;
static BlockDriver *first_drv;

int path_is_absolute(const char *path)
{
    const char *p;
#ifdef _WIN32
    /* specific case for names like: "\\.\d:" */
    if (*path == '/' || *path == '\\')
        return 1;
#endif
    p = strchr(path, ':');
    if (p)
        p++;
    else
        p = path;
#ifdef _WIN32
    return (*p == '/' || *p == '\\');
#else
    return (*p == '/');
#endif
}

/* if filename is absolute, just copy it to dest. Otherwise, build a
   path to it by considering it is relative to base_path. URL are
   supported. */
void path_combine(char *dest, int dest_size,
                  const char *base_path,
                  const char *filename)
{
    const char *p, *p1;
    int len;

    if (dest_size <= 0)
        return;
    if (path_is_absolute(filename)) {
        pstrcpy(dest, dest_size, filename);
    } else {
        p = strchr(base_path, ':');
        if (p)
            p++;
        else
            p = base_path;
        p1 = strrchr(base_path, '/');
#ifdef _WIN32
        {
            const char *p2;
            p2 = strrchr(base_path, '\\');
            if (!p1 || p2 > p1)
                p1 = p2;
        }
#endif
        if (p1)
            p1++;
        else
            p1 = base_path;
        if (p1 > p)
            p = p1;
        len = p - base_path;
        if (len > dest_size - 1)
            len = dest_size - 1;
        memcpy(dest, base_path, len);
        dest[len] = '\0';
        pstrcat(dest, dest_size, filename);
    }
}


static void bdrv_register(BlockDriver *bdrv)
{
    if (!bdrv->bdrv_aio_read) {
        /* add AIO emulation layer */
        bdrv->bdrv_aio_read = bdrv_aio_read_em;
        bdrv->bdrv_aio_write = bdrv_aio_write_em;
        bdrv->bdrv_aio_cancel = bdrv_aio_cancel_em;
        bdrv->aiocb_size = sizeof(BlockDriverAIOCBSync);
    } else if (!bdrv->bdrv_read && !bdrv->bdrv_pread) {
        /* add synchronous IO emulation layer */
        bdrv->bdrv_read = bdrv_read_em;
        bdrv->bdrv_write = bdrv_write_em;
    }
    bdrv->next = first_drv;
    first_drv = bdrv;
}

/* create a new block device (by default it is empty) */
BlockDriverState *bdrv_new(const char *device_name)
{
    BlockDriverState **pbs, *bs;

    bs = qemu_mallocz(sizeof(BlockDriverState));
    if(!bs)
        return NULL;
    pstrcpy(bs->device_name, sizeof(bs->device_name), device_name);
    if (device_name[0] != '\0') {
        /* insert at the end */
        pbs = &bdrv_first;
        while (*pbs != NULL)
            pbs = &(*pbs)->next;
        *pbs = bs;
    }
    return bs;
}

BlockDriver *bdrv_find_format(const char *format_name)
{
    BlockDriver *drv1;
    for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) {
        if (!strcmp(drv1->format_name, format_name))
            return drv1;
    }
    return NULL;
}

int bdrv_create(BlockDriver *drv,
                const char *filename, int64_t size_in_sectors,
                const char *backing_file, int flags)
{
    if (!drv->bdrv_create)
        return -ENOTSUP;
    return drv->bdrv_create(filename, size_in_sectors, backing_file, flags);
}

#ifdef _WIN32
void get_tmp_filename(char *filename, int size)
{
    char temp_dir[MAX_PATH];

    GetTempPath(MAX_PATH, temp_dir);
    GetTempFileName(temp_dir, "qem", 0, filename);
}
#else
void get_tmp_filename(char *filename, int size)
{
    int fd;
    /* XXX: race condition possible */
    pstrcpy(filename, size, "/tmp/vl.XXXXXX");
    fd = mkstemp(filename);
    close(fd);
}
#endif

#ifdef _WIN32
static int is_windows_drive_prefix(const char *filename)
{
    return (((filename[0] >= 'a' && filename[0] <= 'z') ||
             (filename[0] >= 'A' && filename[0] <= 'Z')) &&
            filename[1] == ':');
}

static int is_windows_drive(const char *filename)
{
    if (is_windows_drive_prefix(filename) &&
        filename[2] == '\0')
        return 1;
    if (strstart(filename, "\\\\.\\", NULL) ||
        strstart(filename, "//./", NULL))
        return 1;
    return 0;
}
#endif

static BlockDriver *find_protocol(const char *filename)
{
    BlockDriver *drv1;
    char protocol[128];
    int len;
    const char *p;

#ifdef _WIN32
    if (is_windows_drive(filename) ||
        is_windows_drive_prefix(filename))
        return &bdrv_raw;
#endif
    p = strchr(filename, ':');
    if (!p)
        return &bdrv_raw;
    len = p - filename;
    if (len > sizeof(protocol) - 1)
        len = sizeof(protocol) - 1;
    memcpy(protocol, filename, len);
    protocol[len] = '\0';
    for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) {
        if (drv1->protocol_name &&
            !strcmp(drv1->protocol_name, protocol))
            return drv1;
    }
    return NULL;
}

/* XXX: force raw format if block or character device ? It would
   simplify the BSD case */
static BlockDriver *find_image_format(const char *filename)
{
    int ret, score, score_max;
    BlockDriver *drv1, *drv;
    uint8_t buf[2048];
    BlockDriverState *bs;

    /* detect host devices. By convention, /dev/cdrom[N] is always
       recognized as a host CDROM */
    if (strstart(filename, "/dev/cdrom", NULL))
        return &bdrv_host_device;
#ifdef _WIN32
    if (is_windows_drive(filename))
        return &bdrv_host_device;
#else
    {
        struct stat st;
        if (stat(filename, &st) >= 0 &&
            (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode))) {
            return &bdrv_host_device;
        }
    }
#endif

    drv = find_protocol(filename);
    /* no need to test disk image formats for vvfat */
    if (drv == &bdrv_vvfat)
        return drv;

    ret = bdrv_file_open(&bs, filename, BDRV_O_RDONLY);
    if (ret < 0)
        return NULL;
    ret = bdrv_pread(bs, 0, buf, sizeof(buf));
    bdrv_delete(bs);
    if (ret < 0) {
        return NULL;
    }

    score_max = 0;
    for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) {
        if (drv1->bdrv_probe) {
            score = drv1->bdrv_probe(buf, ret, filename);
            if (score > score_max) {
                score_max = score;
                drv = drv1;
            }
        }
    }
    return drv;
}

int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
{
    BlockDriverState *bs;
    int ret;

    bs = bdrv_new("");
    if (!bs)
        return -ENOMEM;
    ret = bdrv_open2(bs, filename, flags | BDRV_O_FILE, NULL);
    if (ret < 0) {
        bdrv_delete(bs);
        return ret;
    }
    *pbs = bs;
    return 0;
}

int bdrv_open(BlockDriverState *bs, const char *filename, int flags)
{
    return bdrv_open2(bs, filename, flags, NULL);
}

int bdrv_open2(BlockDriverState *bs, const char *filename, int flags,
               BlockDriver *drv)
{
    int ret, open_flags;
    char tmp_filename[PATH_MAX];
    char backing_filename[PATH_MAX];

    bs->read_only = 0;
    bs->is_temporary = 0;
    bs->encrypted = 0;

    if (flags & BDRV_O_SNAPSHOT) {
        BlockDriverState *bs1;
        int64_t total_size;

        /* if snapshot, we create a temporary backing file and open it
           instead of opening 'filename' directly */

        /* if there is a backing file, use it */
        bs1 = bdrv_new("");
        if (!bs1) {
            return -ENOMEM;
        }
        if (bdrv_open(bs1, filename, 0) < 0) {
            bdrv_delete(bs1);
            return -1;
        }
        total_size = bdrv_getlength(bs1) >> SECTOR_BITS;
        bdrv_delete(bs1);

        get_tmp_filename(tmp_filename, sizeof(tmp_filename));
        realpath(filename, backing_filename);
        if (bdrv_create(&bdrv_qcow2, tmp_filename,
                        total_size, backing_filename, 0) < 0) {
            return -1;
        }
        filename = tmp_filename;
        bs->is_temporary = 1;
    }

    pstrcpy(bs->filename, sizeof(bs->filename), filename);
    if (flags & BDRV_O_FILE) {
        drv = find_protocol(filename);
        if (!drv)
            return -ENOENT;
    } else {
        if (!drv) {
            drv = find_image_format(filename);
            if (!drv)
                return -1;
        }
    }
    bs->drv = drv;
    bs->opaque = qemu_mallocz(drv->instance_size);
    if (bs->opaque == NULL && drv->instance_size > 0)
        return -1;
    /* Note: for compatibility, we open disk image files as RDWR, and
       RDONLY as fallback */
    if (!(flags & BDRV_O_FILE))
        open_flags = BDRV_O_RDWR | (flags & BDRV_O_DIRECT);
    else
        open_flags = flags & ~(BDRV_O_FILE | BDRV_O_SNAPSHOT);
    ret = drv->bdrv_open(bs, filename, open_flags);
    if (ret == -EACCES && !(flags & BDRV_O_FILE)) {
        ret = drv->bdrv_open(bs, filename, BDRV_O_RDONLY);
        bs->read_only = 1;
    }
    if (ret < 0) {
        qemu_free(bs->opaque);
        bs->opaque = NULL;
        bs->drv = NULL;
        return ret;
    }
    if (drv->bdrv_getlength) {
        bs->total_sectors = bdrv_getlength(bs) >> SECTOR_BITS;
    }
#ifndef _WIN32
    if (bs->is_temporary) {
        unlink(filename);
    }
#endif
    if (bs->backing_file[0] != '\0') {
        /* if there is a backing file, use it */
        bs->backing_hd = bdrv_new("");
        if (!bs->backing_hd) {
        fail:
            bdrv_close(bs);
            return -ENOMEM;
        }
        path_combine(backing_filename, sizeof(backing_filename),
                     filename, bs->backing_file);
        if (bdrv_open(bs->backing_hd, backing_filename, 0) < 0)
            goto fail;
    }

    /* call the change callback */
    bs->media_changed = 1;
    if (bs->change_cb)
        bs->change_cb(bs->change_opaque);

    return 0;
}

void bdrv_close(BlockDriverState *bs)
{
    if (bs->drv) {
        if (bs->backing_hd)
            bdrv_delete(bs->backing_hd);
        bs->drv->bdrv_close(bs);
        qemu_free(bs->opaque);
#ifdef _WIN32
        if (bs->is_temporary) {
            unlink(bs->filename);
        }
#endif
        bs->opaque = NULL;
        bs->drv = NULL;

        /* call the change callback */
        bs->media_changed = 1;
        if (bs->change_cb)
            bs->change_cb(bs->change_opaque);
    }
}

void bdrv_delete(BlockDriverState *bs)
{
    /* XXX: remove the driver list */
    bdrv_close(bs);
    qemu_free(bs);
}

/* commit COW file into the raw image */
int bdrv_commit(BlockDriverState *bs)
{
    BlockDriver *drv = bs->drv;
    int64_t i, total_sectors;
    int n, j;
    unsigned char sector[512];

    if (!drv)
        return -ENOMEDIUM;

    if (bs->read_only) {
	return -EACCES;
    }

    if (!bs->backing_hd) {