x49gp/block.c
2018-08-28 12:42:54 -04:00

677 lines
14 KiB
C

/* $Id: block.c,v 1.1 2008/12/11 12:18:17 ecd Exp $
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include "qemu-common.h"
#include <block.h>
#include "block_int.h"
#define SECTOR_BITS 9
#define SECTOR_SIZE (1 << SECTOR_BITS)
static BlockDriverState *bdrv_first;
static BlockDriver *first_drv;
#ifndef ENOMEDIUM
#define ENOMEDIUM ENODEV
#endif
static void bdrv_close(BlockDriverState *bs);
static 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. */
static 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);
}
}
#ifdef _WIN32
void get_tmp_filename(char *filename, int size)
{
char temp_dir[MAX_PATH];
GetTempPath(MAX_PATH, temp_dir);
GetTempFileName(temp_dir, "x49", 0, filename);
}
#else
void get_tmp_filename(char *filename, int size)
{
int fd;
/* XXX: race condition possible */
pstrcpy(filename, size, "/tmp/x49gp.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) {
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr,
"%s:%u: protocol '%s', drv->protocol_name '%s'\n",
__FUNCTION__, __LINE__, protocol, drv1->protocol_name);
#endif
if (drv1->protocol_name &&
!strcmp(drv1->protocol_name, protocol)) {
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: protocol '%s', drv %p\n",
__FUNCTION__, __LINE__, protocol, drv1);
#endif
return drv1;
}
}
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: protocol '%s', NULL\n",
__FUNCTION__, __LINE__, protocol);
#endif
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;
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_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);
}
static void
bdrv_register(BlockDriver *bdrv)
{
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;
}
/**
* Truncate file to 'offset' bytes (needed only for file protocols)
*/
int
bdrv_truncate(BlockDriverState *bs, int64_t offset)
{
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
if (!drv->bdrv_truncate)
return -ENOTSUP;
return drv->bdrv_truncate(bs, offset);
}
/**
* Length of a file in bytes. Return < 0 if error or unknown.
*/
int64_t
bdrv_getlength(BlockDriverState *bs)
{
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
if (!drv->bdrv_getlength) {
/* legacy mode */
return bs->total_sectors * SECTOR_SIZE;
}
return drv->bdrv_getlength(bs);
}
int
bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
{
BlockDriverState *bs;
int ret;
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: filename '%s'\n",
__FUNCTION__, __LINE__, filename);
#endif
bs = bdrv_new("");
if (!bs)
return -ENOMEM;
ret = bdrv_open(bs, filename, flags | BDRV_O_FILE);
if (ret < 0) {
bdrv_delete(bs);
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: '%s': %d\n",
__FUNCTION__, __LINE__, filename, ret);
#endif
return ret;
}
*pbs = bs;
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: return 0\n", __FUNCTION__, __LINE__);
#endif
return 0;
}
int
bdrv_open(BlockDriverState *bs, const char *filename, int flags)
{
int ret, open_flags;
char backing_filename[1024];
BlockDriver *drv = NULL;
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: filename '%s'\n",
__FUNCTION__, __LINE__, filename);
#endif
bs->read_only = 0;
bs->is_temporary = 0;
bs->encrypted = 0;
pstrcpy(bs->filename, sizeof(bs->filename), filename);
if (flags & BDRV_O_FILE) {
drv = find_protocol(filename);
if (!drv) {
#ifdef DEBUG_X49GP_BLOCK
f printf(stderr, "%s:%u: drv: %p\n",
__FUNCTION__, __LINE__, drv);
#endif
return -ENOENT;
}
} else {
if (!drv) {
drv = find_image_format(filename);
if (!drv) {
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: drv: %p\n",
__FUNCTION__, __LINE__, drv);
#endif
return -1;
}
}
}
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: drv: %p\n", __FUNCTION__, __LINE__, drv);
#endif
bs->drv = drv;
bs->opaque = qemu_mallocz(drv->instance_size);
if (bs->opaque == NULL && drv->instance_size > 0) {
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: no opaque\n", __FUNCTION__, __LINE__);
#endif
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;
else
open_flags = flags & ~(BDRV_O_FILE);
ret = drv->bdrv_open(bs, filename, open_flags);
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: drv->bdrv_open: %d\n",
__FUNCTION__, __LINE__, ret);
#endif
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;
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: return %d\n",
__FUNCTION__, __LINE__, ret);
#endif
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);
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: return -ENOMEM\n",
__FUNCTION__, __LINE__);
#endif
return -ENOMEM;
}
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: combine '%s' '%s'\n",
__FUNCTION__, __LINE__, filename, bs->backing_file);
#endif
path_combine(backing_filename, sizeof(backing_filename),
filename, bs->backing_file);
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: combine: '%s'\n",
__FUNCTION__, __LINE__, backing_filename);
#endif
if (bdrv_open(bs->backing_hd, backing_filename, 0) < 0) {
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: backing fail\n",
__FUNCTION__, __LINE__);
#endif
goto fail;
}
}
/* call the change callback */
bs->media_changed = 1;
if (bs->change_cb)
bs->change_cb(bs->change_opaque);
#ifdef DEBUG_X49GP_BLOCK
fprintf(stderr, "%s:%u: return 0\n", __FUNCTION__, __LINE__);
#endif
return 0;
}
static void
bdrv_close(BlockDriverState *bs)
{
if (NULL == bs->drv)
return;
/* call the change callback */
bs->media_changed = 1;
if (bs->change_cb)
bs->change_cb(bs->change_opaque);
if (bs->backing_hd)
bdrv_delete(bs->backing_hd);
bs->drv->bdrv_close(bs);
#ifdef _WIN32
if (bs->is_temporary) {
unlink(bs->filename);
}
#endif
qemu_free(bs->opaque);
bs->opaque = NULL;
bs->drv = NULL;
}
void
bdrv_delete(BlockDriverState *bs)
{
/* XXX: remove the driver list */
bdrv_close(bs);
qemu_free(bs);
}
/* return < 0 if error. See bdrv_write() for the return codes */
int
bdrv_read(BlockDriverState * bs, int64_t sector_num,
uint8_t * buf, int nb_sectors)
{
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
memcpy(buf, bs->boot_sector_data, 512);
sector_num++;
nb_sectors--;
buf += 512;
if (nb_sectors == 0)
return 0;
}
if (drv->bdrv_pread) {
int ret, len;
len = nb_sectors * 512;
ret = drv->bdrv_pread(bs, sector_num * 512, buf, len);
if (ret < 0)
return ret;
else if (ret != len)
return -EINVAL;
else
return 0;
} else {
return drv->bdrv_read(bs, sector_num, buf, nb_sectors);
}
}
/* Return < 0 if error. Important errors are:
-EIO generic I/O error (may happen for all errors)
-ENOMEDIUM No media inserted.
-EINVAL Invalid sector number or nb_sectors
-EACCES Trying to write a read-only device
*/
static int
bdrv_write(BlockDriverState * bs, int64_t sector_num,
const uint8_t * buf, int nb_sectors)
{
BlockDriver *drv = bs->drv;
if (!bs->drv)
return -ENOMEDIUM;
if (bs->read_only)
return -EACCES;
if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
memcpy(bs->boot_sector_data, buf, 512);
}
if (drv->bdrv_pwrite) {
int ret, len;
len = nb_sectors * 512;
ret = drv->bdrv_pwrite(bs, sector_num * 512, buf, len);
if (ret < 0)
return ret;
else if (ret != len)
return -EIO;
else
return 0;
} else {
return drv->bdrv_write(bs, sector_num, buf, nb_sectors);
}
}
static int
bdrv_pread_em(BlockDriverState * bs, int64_t offset, uint8_t * buf, int count1)
{
uint8_t tmp_buf[SECTOR_SIZE];
int len, nb_sectors, count;
int64_t sector_num;
count = count1;
/* first read to align to sector start */
len = (SECTOR_SIZE - offset) & (SECTOR_SIZE - 1);
if (len > count)
len = count;
sector_num = offset >> SECTOR_BITS;
if (len > 0) {
if (bdrv_read(bs, sector_num, tmp_buf, 1) < 0)
return -EIO;
memcpy(buf, tmp_buf + (offset & (SECTOR_SIZE - 1)), len);
count -= len;
if (count == 0)
return count1;
sector_num++;
buf += len;
}
/* read the sectors "in place" */
nb_sectors = count >> SECTOR_BITS;
if (nb_sectors > 0) {
if (bdrv_read(bs, sector_num, buf, nb_sectors) < 0)
return -EIO;
sector_num += nb_sectors;
len = nb_sectors << SECTOR_BITS;
buf += len;
count -= len;
}
/* add data from the last sector */
if (count > 0) {
if (bdrv_read(bs, sector_num, tmp_buf, 1) < 0)
return -EIO;
memcpy(buf, tmp_buf, count);
}
return count1;
}
static int
bdrv_pwrite_em(BlockDriverState * bs, int64_t offset,
const uint8_t * buf, int count1)
{
uint8_t tmp_buf[SECTOR_SIZE];
int len, nb_sectors, count;
int64_t sector_num;
count = count1;
/* first write to align to sector start */
len = (SECTOR_SIZE - offset) & (SECTOR_SIZE - 1);
if (len > count)
len = count;
sector_num = offset >> SECTOR_BITS;
if (len > 0) {
if (bdrv_read(bs, sector_num, tmp_buf, 1) < 0)
return -EIO;
memcpy(tmp_buf + (offset & (SECTOR_SIZE - 1)), buf, len);
if (bdrv_write(bs, sector_num, tmp_buf, 1) < 0)
return -EIO;
count -= len;
if (count == 0)
return count1;
sector_num++;
buf += len;
}
/* write the sectors "in place" */
nb_sectors = count >> SECTOR_BITS;
if (nb_sectors > 0) {
if (bdrv_write(bs, sector_num, buf, nb_sectors) < 0)
return -EIO;
sector_num += nb_sectors;
len = nb_sectors << SECTOR_BITS;
buf += len;
count -= len;
}
/* add data from the last sector */
if (count > 0) {
if (bdrv_read(bs, sector_num, tmp_buf, 1) < 0)
return -EIO;
memcpy(tmp_buf, buf, count);
if (bdrv_write(bs, sector_num, tmp_buf, 1) < 0)
return -EIO;
}
return count1;
}
/**
* Read with byte offsets (needed only for file protocols)
*/
int
bdrv_pread(BlockDriverState * bs, int64_t offset, void *buf1, int count1)
{
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
if (!drv->bdrv_pread)
return bdrv_pread_em(bs, offset, buf1, count1);
return drv->bdrv_pread(bs, offset, buf1, count1);
}
/**
* Write with byte offsets (needed only for file protocols)
*/
int
bdrv_pwrite(BlockDriverState * bs, int64_t offset, const void *buf1, int count1)
{
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
if (!drv->bdrv_pwrite)
return bdrv_pwrite_em(bs, offset, buf1, count1);
return drv->bdrv_pwrite(bs, offset, buf1, count1);
}
void
bdrv_flush(BlockDriverState *bs)
{
if (bs->drv->bdrv_flush)
bs->drv->bdrv_flush(bs);
if (bs->backing_hd)
bdrv_flush(bs->backing_hd);
}
void
bdrv_init(void)
{
/* bdrv_register(&bdrv_raw); */
/* bdrv_register(&bdrv_host_device); */
bdrv_register(&bdrv_qcow);
bdrv_register(&bdrv_vvfat);
}