[Qemu-devel] multi-partition block driver

[Qemu-devel] multi-partition block driver

[Aleksandar Kanchev]

[-- Attachment #1: Type: text/html, Size: 2234 bytes --]

[-- Attachment #2: qemu-block-multipart.patch --]
[-- Type: text/x-patch, Size: 16753 bytes --]

INSTALL: 'tar -xzf qemu-0.9.1.tar.gz; patch -p0 < qemu-block-multipart.patch'
diff -Nurp qemu-0.9.1/block.c qemu-0.9.1-multipart/block.c
--- qemu-0.9.1/block.c	2008-01-06 20:38:42.000000000 +0100
+++ qemu-0.9.1-multipart/block.c	2008-03-03 09:56:42.000000000 +0100
@@ -273,8 +273,8 @@ static BlockDriver *find_image_format(co
 #endif
 
     drv = find_protocol(filename);
-    /* no need to test disk image formats for vvfat */
-    if (drv == &bdrv_vvfat)
+    /* no need to test disk image formats for vvfat or multipart */
+    if (drv == &bdrv_vvfat || drv == &bdrv_multipart)
         return drv;
 
     ret = bdrv_file_open(&bs, filename, BDRV_O_RDONLY);
@@ -1294,6 +1294,7 @@ void bdrv_init(void)
     bdrv_register(&bdrv_vvfat);
     bdrv_register(&bdrv_qcow2);
     bdrv_register(&bdrv_parallels);
+    bdrv_register(&bdrv_multipart);
 }
 
 void *qemu_aio_get(BlockDriverState *bs, BlockDriverCompletionFunc *cb,
diff -Nurp qemu-0.9.1/block.h qemu-0.9.1-multipart/block.h
--- qemu-0.9.1/block.h	2008-01-06 20:38:42.000000000 +0100
+++ qemu-0.9.1-multipart/block.h	2008-03-03 09:57:04.000000000 +0100
@@ -16,6 +16,7 @@ extern BlockDriver bdrv_vpc;
 extern BlockDriver bdrv_vvfat;
 extern BlockDriver bdrv_qcow2;
 extern BlockDriver bdrv_parallels;
+extern BlockDriver bdrv_multipart;
 
 typedef struct BlockDriverInfo {
     /* in bytes, 0 if irrelevant */
diff -Nurp qemu-0.9.1/block-multipart.c qemu-0.9.1-multipart/block-multipart.c
--- qemu-0.9.1/block-multipart.c	1970-01-01 01:00:00.000000000 +0100
+++ qemu-0.9.1-multipart/block-multipart.c	2008-03-03 17:04:04.000000000 +0100
@@ -0,0 +1,596 @@
+/*
+ * QEMU Block driver for multi-partition images (virtually merges disk images)
+ *
+ * Copyright (c) 2008 Aleksandar Kanchev
+ *
+ * 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.
+ */
+/*
+ * The block driver expects a mini config file with the following format:
+ *
+ * The first line tells the driver if it should generate a
+ * partition table. If it is set to the word "dynamic", a partition table is
+ * generated, anything else (including an empty line) tells the driver not to
+ * modify the MBR.
+ *
+ * The second line specifies a disk_image with the drive's first track. It could
+ * be a simple raw 512b file containing the MBR. It could be even smaller,
+ * containing only the MBR's code. The first track is always kept in memory and
+ * changes are mirrored to the disk image if it's available. If the line is left
+ * empty, all changes will be lost when the VM is powered down.
+ *
+ * Lines from 3 to 6 contain the four partitions of the drive. The partition
+ * format is:
+ *   <disk_image>[,<partition type>[,<partition status>]]
+ * example:
+ *   /dev/hda1,83,80
+ *   /dev/hda1,83,a
+ *   /dev/hda1,83
+ * The first two lines are equivalent, where 'a' is 0x80 or "active" and 0x83
+ * is the linux partition type. The partition type and status are only
+ * relevant if the first line is set to "dynamic".
+ *
+ * The rest of the config file is ignored.
+ */
+#include "qemu-common.h"
+#include "block_int.h"
+
+#include <string.h>
+#include <stdarg.h>
+
+
+#define	FORMAT_NAME			"multipart"
+#define	PROTOCOL_NAME		"multi"
+
+#define	CONFIG_LINE_LEN		1024
+
+#define	BLOCK_SHIFT			9
+#define	BLOCK_SIZE			(1 << BLOCK_SHIFT)
+#define TRACK_SECTORS		63
+#define	HEADS				255
+
+
+typedef struct {
+	uint8_t head;
+	uint8_t	sector;
+	uint8_t cylinder;
+} __attribute__((packed)) chs_t;
+
+typedef struct {
+	uint8_t status;	// 0x80 = bootable, 0x00 = non-bootable, other = malformed
+	chs_t chs_start;
+	uint8_t type; // 0x07 = HPFS/NTFS, 0x82 = Linux swap, 0x83 = Linux ...
+	chs_t chs_end;
+	uint32_t lba_start;
+	uint32_t lba_length;
+} __attribute__((packed)) partition_t;
+
+typedef struct {
+	uint8_t code[440];
+	uint8_t disk_signature[4];
+	uint8_t zero[2];
+	partition_t partition[4];
+	uint8_t magic[2];
+} __attribute__((packed)) mbr_t;
+
+typedef union {
+	uint8_t buf[TRACK_SECTORS * BLOCK_SIZE];
+	mbr_t mbr;
+} first_track_t;
+
+typedef struct BdrvMultipartState {
+	first_track_t first_track;
+	BlockDriverState *bs_first_track;
+	BlockDriverState *bs_partition[4];
+} BdrvMultipartState;
+
+typedef struct {
+	int16_t status;
+	int16_t type;
+	char *filename;
+} config_partition_t;
+
+typedef struct {
+	uint8_t dynamic;
+	char *ft_filename;
+	config_partition_t partition[4];
+} config_t;
+
+
+static void info(const char *format, ...)
+{
+	va_list ap;
+
+	fprintf(stderr, "qemu %s: ", FORMAT_NAME);
+
+	va_start(ap, format);
+	vfprintf(stderr, format, ap);
+	va_end(ap);
+
+	fprintf(stderr, "\n");
+}
+
+static int16_t get_hex(const char *str)
+{
+	int16_t ret = -1;
+
+	if (str[0] == '0' && tolower(str[1]) == 'x')
+		str += 2;
+
+	if (*str != '\0') {
+		int i, ch;
+
+		ret = 0;
+		for (i = 0; i < 2 && str[i] != '\0'; i++) {
+			ret <<= 4;
+
+			ch = tolower(str[i]);
+			if (ch >= 'a' && ch <= 'f')
+				ret += 10 + ch - 'a';
+			else if (ch >= '0' && ch <= '9')
+				ret += ch - '0';
+		}
+	}
+
+	return ret;
+}
+
+static char *pstrdup(const char *src)
+{
+	const char *p = src;
+	char *ret;
+	size_t len;
+
+	while (*p != '\0')
+		p++;
+
+	len = p - src;
+	ret = qemu_mallocz(len + 1);
+	if (ret != NULL)
+		memcpy(ret, src, len);
+
+	return ret;
+}
+
+static char *pgetline(int fd)
+{
+	static char buf[CONFIG_LINE_LEN + 1];
+	char *p;
+	int r;
+
+	for (p = buf; (r = read(fd, p, 1)) > 0; p++) {
+		if (*p == '\r' || *p == '\n')
+			break;
+
+		if ((p - buf + 1) >= (sizeof(buf) - 1)) {
+			p++;
+			break;
+		}
+	}
+
+	*p = '\0';
+
+	if (r <= 0 && p == buf)
+		return NULL;
+
+	return buf;
+}
+
+static void config_delete(config_t *cfg)
+{
+	int i;
+
+	if (cfg->ft_filename != NULL)
+		qemu_free(cfg->ft_filename);
+
+	for (i = 0; i < 4 && cfg->partition[i].filename != NULL; i++)
+		qemu_free(cfg->partition[i].filename);
+
+	qemu_free(cfg);
+}
+
+static int config_parse(const char *filename, config_t **pcfg)
+{
+	int nline;
+	int fd;
+	char *line;
+	char *p, *q;
+	config_t *cfg;
+
+	cfg = qemu_mallocz(sizeof(config_t));
+	if (!cfg)
+		return -ENOMEM;
+
+    strstart(filename, PROTOCOL_NAME ":", &filename);
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	for (nline = 0; nline < 6; nline++) {
+		line = pgetline(fd);
+		if (!line) {
+			if (nline < 3) {
+				info("config is too short");
+				goto error;
+			}
+			break;
+		}
+
+		/* dynamic */
+		if (nline == 0) {
+			if (tolower(*line) == 'd')
+				cfg->dynamic = 1;
+
+		/* first track */
+		} else if (nline == 1) {
+			if (*line != '\0')
+				cfg->ft_filename = pstrdup(line);
+
+		/* partitions */
+		} else {
+			config_partition_t *partition = &(cfg->partition[nline - 2]);
+
+			p = strrchr(line, ',');
+			if (p != NULL) {
+				partition->type = get_hex(p + 1);
+
+				*p = '\0';
+				q = strrchr(line, ',');
+				if (q != NULL) {
+					partition->status = partition->type;
+					if (p[1] == 'a' && p[2] == '\0')
+						partition->status = 0x80;
+ 
+					partition->type = get_hex(q + 1);
+					*q = '\0';
+				}
+			}
+
+			if (*line == '\0') {
+				if (nline < 3) {
+					info("at least one partition is required");
+					goto error;
+				}
+				break;
+			}
+
+			partition->filename = pstrdup(line);
+		}
+	}
+
+	close(fd);
+	*pcfg = cfg;
+
+	return 0;
+
+error:
+	close(fd);
+	config_delete(cfg);
+
+	return -1;
+}
+
+static inline int first_track_init(BlockDriverState *bs, const char *filename, int flags)
+{
+	BdrvMultipartState *bs_mp = bs->opaque;
+
+	memset(bs_mp->first_track.buf, 0, sizeof(bs_mp->first_track));
+	bs->total_sectors = sizeof(bs_mp->first_track) >> BLOCK_SHIFT;
+
+	if (filename != NULL) {
+		int ret;
+		int64_t len;
+		BlockDriverState *bs_ft;
+
+		bs_ft = bdrv_new("");
+		if (!bs_ft)
+			return -ENOMEM;
+
+		ret = bdrv_open(bs_ft, filename, flags);
+		if (ret < 0) {
+			info("unable to open mbr image %s", filename);
+			return ret;
+		}
+
+		len = bdrv_getlength(bs_ft);
+		if (len > sizeof(bs_mp->first_track))
+			len = sizeof(bs_mp->first_track);
+
+		ret = bdrv_pread(bs_ft, 0, bs_mp->first_track.buf, len);
+		if (ret < 0) {
+			info("unable to read mbr image %s", filename);
+			bdrv_delete(bs_ft);
+			return ret;
+		}
+
+		if (bs_ft->read_only)
+			bdrv_delete(bs_ft);
+		else
+			bs_mp->bs_first_track = bs_ft;
+	}
+
+	return 0;
+}
+
+static void lbatochs(uint32_t lba, chs_t *pchs)
+{
+	uint32_t c, h, s;
+
+	c = lba / (HEADS * TRACK_SECTORS);
+	h = (lba % (HEADS * TRACK_SECTORS)) / TRACK_SECTORS;
+	s = (lba % (HEADS * TRACK_SECTORS)) % TRACK_SECTORS + 1;
+
+	pchs->head = h > 254 ? 254 : (uint8_t) h;
+	pchs->sector = s > 63 ? 63 : (uint8_t) s;
+
+	if (c > 1023)
+		c = 1023;
+
+	pchs->sector |= (uint8_t) ((c >> 2) & 0xc0);
+	pchs->cylinder = (uint8_t) (c & 0xff);
+}
+
+static inline int partitions_init(BlockDriverState *bs, int flags, config_t *cfg)
+{
+	int i, ret = 0;
+	mbr_t *mbr;
+	BdrvMultipartState *bs_mp = bs->opaque;
+	BlockDriverState *bs_part;
+
+	mbr = &(bs_mp->first_track.mbr);
+	if (cfg->dynamic) {
+		mbr->magic[0] = 0x55;
+		mbr->magic[1] = 0xAA;
+	}
+
+	for (i = 0; i < 4 && cfg->partition[i].filename != NULL; i++) {
+		config_partition_t *cpart = &(cfg->partition[i]);
+
+		bs_part = bdrv_new("");
+		if (!bs_part) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		ret = bdrv_open(bs_part, cpart->filename, flags);
+		if (ret < 0) {
+			info("unable to open partition image %s", cpart->filename);
+			qemu_free(bs_part);
+			break;
+		}
+
+		if (bs_part->total_sectors == 0) {
+			info("zero length partition %s", cpart->filename);
+			bdrv_delete(bs_part);
+			break;
+		}
+
+		bs_mp->bs_partition[i] = bs_part;
+
+		if (cfg->dynamic) {
+			partition_t *partition = &(mbr->partition[i]);
+
+			partition->lba_start = cpu_to_le32(bs->total_sectors);
+			lbatochs(partition->lba_start, &(partition->chs_start));
+
+			partition->lba_length = cpu_to_le32(bs_part->total_sectors);
+			lbatochs(bs->total_sectors + bs_part->total_sectors - 1,
+						&(partition->chs_end));
+
+			if (cpart->status >= 0)
+				partition->status = cpart->status;
+
+			if (cpart->type >= 0)
+				partition->type = cpart->type;
+		}
+
+		bs_mp->bs_partition[i] = bs_part;
+		bs->total_sectors += bs_part->total_sectors;
+	}
+
+	if (ret < 0) {
+		for (i = 0; i < 4 && bs_mp->bs_partition[i] != NULL; i++)
+			bdrv_delete(bs_mp->bs_partition[i]);
+	}
+
+	return ret;
+}
+
+static int ft_image_write(BlockDriverState *bs, int64_t sector_num,
+					const uint8_t *buf, int nb_sectors)
+{
+	int ret = 0;
+	int64_t write_offset, write_length;
+	int64_t bdrv_length;
+
+	write_offset = sector_num << BLOCK_SHIFT;
+	bdrv_length = bdrv_getlength(bs);
+
+	if (write_offset < bdrv_length) {
+		write_length = nb_sectors << BLOCK_SHIFT;
+		if ((write_offset + write_length) > bdrv_length)
+			write_length = bdrv_length - write_offset;
+
+		ret = bdrv_pwrite(bs, write_offset, buf, write_length);
+	}
+
+	return ret;
+}
+
+
+static int multipart_open(BlockDriverState *bs, const char *filename, int flags)
+{
+	int i, ret;
+	config_t *cfg;
+	BdrvMultipartState *bs_mp = bs->opaque;
+
+	ret = config_parse(filename, &cfg);
+	if (ret < 0)
+		return ret;
+
+	ret = first_track_init(bs, cfg->ft_filename, flags);
+	if (ret < 0) {
+		config_delete(cfg);
+		return ret;
+	}
+
+	ret = partitions_init(bs, flags, cfg);
+	if (ret >= 0 && cfg->dynamic && bs_mp->bs_first_track) {
+		ret = ft_image_write(bs_mp->bs_first_track, 0, bs_mp->first_track.buf, 1);
+		if (ret < 0) {
+			info("writing MBR to image %s failed", cfg->ft_filename);
+
+			/* clean up the partitions */
+			for (i = 0; i < 4 && bs_mp->bs_partition[i] != NULL; i++)
+				bdrv_delete(bs_mp->bs_partition[i]);
+		}
+	}
+
+	config_delete(cfg);
+
+	if (ret < 0 && bs_mp->bs_first_track != NULL)
+		bdrv_delete(bs_mp->bs_first_track);
+
+	return ret;
+}
+
+static int multipart_read(BlockDriverState *bs, int64_t sector_num,
+                     uint8_t *buf, int nb_sectors)
+{
+	int i, ret = 0;
+	int read_sectors;
+	int64_t ft_nsectors;
+	BdrvMultipartState *bs_mp = bs->opaque;
+	BlockDriverState *bs_part;
+
+	ft_nsectors = sizeof(bs_mp->first_track) >> BLOCK_SHIFT;
+	if (sector_num < ft_nsectors) {
+		read_sectors = nb_sectors;
+		if ((sector_num + read_sectors) > ft_nsectors)
+			read_sectors = ft_nsectors - sector_num;
+
+		memcpy(buf, bs_mp->first_track.buf + (sector_num << BLOCK_SHIFT),
+					read_sectors << BLOCK_SHIFT);
+
+		sector_num += read_sectors;
+		nb_sectors -= read_sectors;
+		buf += read_sectors << BLOCK_SHIFT;
+	}
+
+	sector_num -= ft_nsectors;
+	for (i = 0; i < 4 && bs_mp->bs_partition[i] != NULL && nb_sectors > 0; i++) {
+		bs_part = bs_mp->bs_partition[i];
+
+		if (sector_num < bs_part->total_sectors) {
+			read_sectors = nb_sectors;
+			if ((sector_num + read_sectors) > bs_part->total_sectors)
+				read_sectors = bs_part->total_sectors - sector_num;
+
+			ret = bdrv_read(bs_part, sector_num, buf, read_sectors);
+			if (ret < 0)
+				break;
+
+			sector_num += read_sectors;
+			nb_sectors -= read_sectors;
+			buf += read_sectors << BLOCK_SHIFT;
+		}
+
+		sector_num -= bs_part->total_sectors;
+	}
+
+	return ret;
+}
+
+static int multipart_write(BlockDriverState *bs, int64_t sector_num,
+                      const uint8_t *buf, int nb_sectors)
+{
+	int i, ret = 0;
+	int write_sectors;
+	int64_t ft_nsectors;
+	BdrvMultipartState *bs_mp = bs->opaque;
+	BlockDriverState *bs_part;
+
+	ft_nsectors = sizeof(bs_mp->first_track) >> BLOCK_SHIFT;
+	if (sector_num < ft_nsectors) {
+		if (bs_mp->bs_first_track != NULL) {
+			ret = ft_image_write(bs_mp->bs_first_track, sector_num,
+									buf, nb_sectors);
+			if (ret < 0)
+				return ret;
+		}
+
+		write_sectors = nb_sectors;
+		if ((sector_num + write_sectors) > ft_nsectors)
+			write_sectors = ft_nsectors - sector_num;
+
+		memcpy(bs_mp->first_track.buf + (sector_num << BLOCK_SHIFT), buf,
+					write_sectors << BLOCK_SHIFT);
+
+		sector_num += write_sectors;
+		nb_sectors -= write_sectors;
+		buf += write_sectors << BLOCK_SHIFT;
+	}
+
+	sector_num -= ft_nsectors;
+	for (i = 0; i < 4 && bs_mp->bs_partition[i] != NULL && nb_sectors > 0; i++) {
+		bs_part = bs_mp->bs_partition[i];
+
+		if (sector_num < bs_part->total_sectors) {
+			write_sectors = nb_sectors;
+			if ((sector_num + write_sectors) > bs_part->total_sectors)
+				write_sectors = bs_part->total_sectors - sector_num;
+
+			ret = bdrv_write(bs_part, sector_num, buf, write_sectors);
+			if (ret < 0)
+				break;
+
+			sector_num += write_sectors;
+			nb_sectors -= write_sectors;
+			buf += write_sectors << BLOCK_SHIFT;
+		}
+
+		sector_num -= bs_part->total_sectors;
+	}
+
+	return ret;
+}
+
+static void multipart_close(BlockDriverState *bs)
+{
+	int i;
+	BdrvMultipartState *bs_mp = bs->opaque;
+
+	if (bs_mp->bs_first_track)
+		bdrv_delete(bs_mp->bs_first_track);
+
+	for (i = 0; i < 4 && bs_mp->bs_partition[i] != NULL; i++)
+		bdrv_delete(bs_mp->bs_partition[i]);
+}
+
+BlockDriver bdrv_multipart = {
+	.format_name = FORMAT_NAME,
+	.instance_size = sizeof(BdrvMultipartState),
+	.bdrv_open = multipart_open,
+	.bdrv_read = multipart_read,
+	.bdrv_write = multipart_write,
+	.bdrv_close = multipart_close,
+	.protocol_name = PROTOCOL_NAME
+};
+
diff -Nurp qemu-0.9.1/Makefile qemu-0.9.1-multipart/Makefile
--- qemu-0.9.1/Makefile	2008-01-06 20:38:41.000000000 +0100
+++ qemu-0.9.1-multipart/Makefile	2008-03-03 09:55:55.000000000 +0100
@@ -40,7 +40,7 @@ recurse-all: $(patsubst %,subdir-%, $(TA
 BLOCK_OBJS=cutils.o
 BLOCK_OBJS+=block-cow.o block-qcow.o aes.o block-vmdk.o block-cloop.o
 BLOCK_OBJS+=block-dmg.o block-bochs.o block-vpc.o block-vvfat.o
-BLOCK_OBJS+=block-qcow2.o block-parallels.o
+BLOCK_OBJS+=block-qcow2.o block-parallels.o block-multipart.o
 
 ######################################################################
 # libqemu_common.a: Target indepedent part of system emulation. The