btrfs-progs/send-stream.c

532 lines
13 KiB
C

/*
* Copyright (C) 2012 Alexander Block. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <uuid/uuid.h>
#include <unistd.h>
#include "send.h"
#include "send-stream.h"
#include "crc32c.h"
#include "utils.h"
struct btrfs_send_stream {
int fd;
char read_buf[BTRFS_SEND_BUF_SIZE];
int cmd;
struct btrfs_cmd_header *cmd_hdr;
struct btrfs_tlv_header *cmd_attrs[BTRFS_SEND_A_MAX + 1];
u32 version;
/*
* end of last successful read, equivalent to start of current
* malformated part of block
*/
size_t stream_pos;
struct btrfs_send_ops *ops;
void *user;
};
/*
* Read len bytes to buf.
* Return:
* 0 - success
* < 0 - negative errno in case of error
* > 0 - no data read, EOF
*/
static int read_buf(struct btrfs_send_stream *sctx, char *buf, size_t len)
{
int ret;
size_t pos = 0;
while (pos < len) {
ssize_t rbytes;
rbytes = read(sctx->fd, buf + pos, len - pos);
if (rbytes < 0) {
ret = -errno;
error("read from stream failed: %m");
goto out;
}
if (rbytes == 0) {
ret = 1;
goto out_eof;
}
pos += rbytes;
}
ret = 0;
out_eof:
if (0 < pos && pos < len) {
error("short read from stream: expected %zu read %zu", len, pos);
ret = -EIO;
} else {
sctx->stream_pos += pos;
}
out:
return ret;
}
/*
* Reads a single command from kernel space and decodes the TLV's into
* sctx->cmd_attrs
*
* Returns:
* 0 - success
* < 0 - an error in the command
*/
static int read_cmd(struct btrfs_send_stream *sctx)
{
int ret;
u16 cmd;
u32 cmd_len;
char *data;
u32 pos;
u32 crc;
u32 crc2;
memset(sctx->cmd_attrs, 0, sizeof(sctx->cmd_attrs));
ASSERT(sizeof(*sctx->cmd_hdr) <= sizeof(sctx->read_buf));
ret = read_buf(sctx, sctx->read_buf, sizeof(*sctx->cmd_hdr));
if (ret < 0)
goto out;
if (ret) {
ret = -EINVAL;
error("unexpected EOF in stream");
goto out;
}
sctx->cmd_hdr = (struct btrfs_cmd_header *)sctx->read_buf;
cmd = le16_to_cpu(sctx->cmd_hdr->cmd);
cmd_len = le32_to_cpu(sctx->cmd_hdr->len);
if (cmd_len + sizeof(*sctx->cmd_hdr) >= sizeof(sctx->read_buf)) {
ret = -EINVAL;
error("command length %u too big for buffer %zu",
cmd_len, sizeof(sctx->read_buf));
goto out;
}
data = sctx->read_buf + sizeof(*sctx->cmd_hdr);
ret = read_buf(sctx, data, cmd_len);
if (ret < 0)
goto out;
if (ret) {
ret = -EINVAL;
error("unexpected EOF in stream");
goto out;
}
crc = le32_to_cpu(sctx->cmd_hdr->crc);
sctx->cmd_hdr->crc = 0;
crc2 = crc32c(0, (unsigned char*)sctx->read_buf,
sizeof(*sctx->cmd_hdr) + cmd_len);
if (crc != crc2) {
ret = -EINVAL;
error("crc32 mismatch in command");
goto out;
}
pos = 0;
while (pos < cmd_len) {
struct btrfs_tlv_header *tlv_hdr;
u16 tlv_type;
u16 tlv_len;
tlv_hdr = (struct btrfs_tlv_header *)data;
tlv_type = le16_to_cpu(tlv_hdr->tlv_type);
tlv_len = le16_to_cpu(tlv_hdr->tlv_len);
if (tlv_type == 0 || tlv_type > BTRFS_SEND_A_MAX
|| tlv_len > BTRFS_SEND_BUF_SIZE) {
error("invalid tlv in cmd tlv_type = %hu, tlv_len = %hu",
tlv_type, tlv_len);
ret = -EINVAL;
goto out;
}
sctx->cmd_attrs[tlv_type] = tlv_hdr;
data += sizeof(*tlv_hdr) + tlv_len;
pos += sizeof(*tlv_hdr) + tlv_len;
}
sctx->cmd = cmd;
ret = 0;
out:
return ret;
}
static int tlv_get(struct btrfs_send_stream *sctx, int attr, void **data, int *len)
{
int ret;
struct btrfs_tlv_header *hdr;
if (attr <= 0 || attr > BTRFS_SEND_A_MAX) {
error("invalid attribute requested, attr = %d", attr);
ret = -EINVAL;
goto out;
}
hdr = sctx->cmd_attrs[attr];
if (!hdr) {
error("attribute %d requested but not present", attr);
ret = -ENOENT;
goto out;
}
*len = le16_to_cpu(hdr->tlv_len);
*data = hdr + 1;
ret = 0;
out:
return ret;
}
#define __TLV_GOTO_FAIL(expr) \
if ((ret = expr) < 0) \
goto tlv_get_failed;
#define __TLV_DO_WHILE_GOTO_FAIL(expr) \
do { \
__TLV_GOTO_FAIL(expr) \
} while (0)
#define TLV_GET(s, attr, data, len) \
__TLV_DO_WHILE_GOTO_FAIL(tlv_get(s, attr, data, len))
#define TLV_CHECK_LEN(expected, got) \
do { \
if (expected != got) { \
error("invalid size for attribute, " \
"expected = %d, got = %d", \
(int)expected, (int)got); \
ret = -EINVAL; \
goto tlv_get_failed; \
} \
} while (0)
#define TLV_GET_INT(s, attr, bits, v) \
do { \
__le##bits *__tmp; \
int __len; \
TLV_GET(s, attr, (void**)&__tmp, &__len); \
TLV_CHECK_LEN(sizeof(*__tmp), __len); \
*v = get_unaligned_le##bits(__tmp); \
} while (0)
#define TLV_GET_U8(s, attr, v) TLV_GET_INT(s, attr, 8, v)
#define TLV_GET_U16(s, attr, v) TLV_GET_INT(s, attr, 16, v)
#define TLV_GET_U32(s, attr, v) TLV_GET_INT(s, attr, 32, v)
#define TLV_GET_U64(s, attr, v) TLV_GET_INT(s, attr, 64, v)
static int tlv_get_string(struct btrfs_send_stream *sctx, int attr, char **str)
{
int ret;
void *data;
int len = 0;
TLV_GET(sctx, attr, &data, &len);
*str = malloc(len + 1);
if (!*str)
return -ENOMEM;
memcpy(*str, data, len);
(*str)[len] = 0;
ret = 0;
tlv_get_failed:
return ret;
}
#define TLV_GET_STRING(s, attr, str) \
__TLV_DO_WHILE_GOTO_FAIL(tlv_get_string(s, attr, str))
static int tlv_get_timespec(struct btrfs_send_stream *sctx,
int attr, struct timespec *ts)
{
int ret;
int len;
struct btrfs_timespec *bts;
TLV_GET(sctx, attr, (void**)&bts, &len);
TLV_CHECK_LEN(sizeof(*bts), len);
ts->tv_sec = le64_to_cpu(bts->sec);
ts->tv_nsec = le32_to_cpu(bts->nsec);
ret = 0;
tlv_get_failed:
return ret;
}
#define TLV_GET_TIMESPEC(s, attr, ts) \
__TLV_DO_WHILE_GOTO_FAIL(tlv_get_timespec(s, attr, ts))
static int tlv_get_uuid(struct btrfs_send_stream *sctx, int attr, u8 *uuid)
{
int ret;
int len;
void *data;
TLV_GET(sctx, attr, &data, &len);
TLV_CHECK_LEN(BTRFS_UUID_SIZE, len);
memcpy(uuid, data, BTRFS_UUID_SIZE);
ret = 0;
tlv_get_failed:
return ret;
}
#define TLV_GET_UUID(s, attr, uuid) \
__TLV_DO_WHILE_GOTO_FAIL(tlv_get_uuid(s, attr, uuid))
static int read_and_process_cmd(struct btrfs_send_stream *sctx)
{
int ret;
char *path = NULL;
char *path_to = NULL;
char *clone_path = NULL;
char *xattr_name = NULL;
void *xattr_data = NULL;
void *data = NULL;
struct timespec at;
struct timespec ct;
struct timespec mt;
u8 uuid[BTRFS_UUID_SIZE];
u8 clone_uuid[BTRFS_UUID_SIZE];
u64 tmp;
u64 tmp2;
u64 ctransid;
u64 clone_ctransid;
u64 mode;
u64 dev;
u64 clone_offset;
u64 offset;
int len;
int xattr_len;
ret = read_cmd(sctx);
if (ret)
goto out;
switch (sctx->cmd) {
case BTRFS_SEND_C_SUBVOL:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_UUID(sctx, BTRFS_SEND_A_UUID, uuid);
TLV_GET_U64(sctx, BTRFS_SEND_A_CTRANSID, &ctransid);
ret = sctx->ops->subvol(path, uuid, ctransid, sctx->user);
break;
case BTRFS_SEND_C_SNAPSHOT:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_UUID(sctx, BTRFS_SEND_A_UUID, uuid);
TLV_GET_U64(sctx, BTRFS_SEND_A_CTRANSID, &ctransid);
TLV_GET_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, clone_uuid);
TLV_GET_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID, &clone_ctransid);
ret = sctx->ops->snapshot(path, uuid, ctransid, clone_uuid,
clone_ctransid, sctx->user);
break;
case BTRFS_SEND_C_MKFILE:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
ret = sctx->ops->mkfile(path, sctx->user);
break;
case BTRFS_SEND_C_MKDIR:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
ret = sctx->ops->mkdir(path, sctx->user);
break;
case BTRFS_SEND_C_MKNOD:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_U64(sctx, BTRFS_SEND_A_MODE, &mode);
TLV_GET_U64(sctx, BTRFS_SEND_A_RDEV, &dev);
ret = sctx->ops->mknod(path, mode, dev, sctx->user);
break;
case BTRFS_SEND_C_MKFIFO:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
ret = sctx->ops->mkfifo(path, sctx->user);
break;
case BTRFS_SEND_C_MKSOCK:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
ret = sctx->ops->mksock(path, sctx->user);
break;
case BTRFS_SEND_C_SYMLINK:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH_LINK, &path_to);
ret = sctx->ops->symlink(path, path_to, sctx->user);
break;
case BTRFS_SEND_C_RENAME:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH_TO, &path_to);
ret = sctx->ops->rename(path, path_to, sctx->user);
break;
case BTRFS_SEND_C_LINK:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH_LINK, &path_to);
ret = sctx->ops->link(path, path_to, sctx->user);
break;
case BTRFS_SEND_C_UNLINK:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
ret = sctx->ops->unlink(path, sctx->user);
break;
case BTRFS_SEND_C_RMDIR:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
ret = sctx->ops->rmdir(path, sctx->user);
break;
case BTRFS_SEND_C_WRITE:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, &offset);
TLV_GET(sctx, BTRFS_SEND_A_DATA, &data, &len);
ret = sctx->ops->write(path, data, offset, len, sctx->user);
break;
case BTRFS_SEND_C_CLONE:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, &offset);
TLV_GET_U64(sctx, BTRFS_SEND_A_CLONE_LEN, &len);
TLV_GET_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, clone_uuid);
TLV_GET_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID, &clone_ctransid);
TLV_GET_STRING(sctx, BTRFS_SEND_A_CLONE_PATH, &clone_path);
TLV_GET_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET, &clone_offset);
ret = sctx->ops->clone(path, offset, len, clone_uuid,
clone_ctransid, clone_path, clone_offset,
sctx->user);
break;
case BTRFS_SEND_C_SET_XATTR:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, &xattr_name);
TLV_GET(sctx, BTRFS_SEND_A_XATTR_DATA, &xattr_data, &xattr_len);
ret = sctx->ops->set_xattr(path, xattr_name, xattr_data,
xattr_len, sctx->user);
break;
case BTRFS_SEND_C_REMOVE_XATTR:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, &xattr_name);
ret = sctx->ops->remove_xattr(path, xattr_name, sctx->user);
break;
case BTRFS_SEND_C_TRUNCATE:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_U64(sctx, BTRFS_SEND_A_SIZE, &tmp);
ret = sctx->ops->truncate(path, tmp, sctx->user);
break;
case BTRFS_SEND_C_CHMOD:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_U64(sctx, BTRFS_SEND_A_MODE, &tmp);
ret = sctx->ops->chmod(path, tmp, sctx->user);
break;
case BTRFS_SEND_C_CHOWN:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_U64(sctx, BTRFS_SEND_A_UID, &tmp);
TLV_GET_U64(sctx, BTRFS_SEND_A_GID, &tmp2);
ret = sctx->ops->chown(path, tmp, tmp2, sctx->user);
break;
case BTRFS_SEND_C_UTIMES:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, &at);
TLV_GET_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, &mt);
TLV_GET_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, &ct);
ret = sctx->ops->utimes(path, &at, &mt, &ct, sctx->user);
break;
case BTRFS_SEND_C_UPDATE_EXTENT:
TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
TLV_GET_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, &offset);
TLV_GET_U64(sctx, BTRFS_SEND_A_SIZE, &tmp);
ret = sctx->ops->update_extent(path, offset, tmp, sctx->user);
break;
case BTRFS_SEND_C_END:
ret = 1;
break;
}
tlv_get_failed:
out:
free(path);
free(path_to);
free(clone_path);
free(xattr_name);
return ret;
}
/*
* If max_errors is 0, then don't stop processing the stream if one of the
* callbacks in btrfs_send_ops structure returns an error. If greater than
* zero, stop after max_errors errors happened.
*/
int btrfs_read_and_process_send_stream(int fd,
struct btrfs_send_ops *ops, void *user,
int honor_end_cmd,
u64 max_errors)
{
int ret;
struct btrfs_send_stream sctx;
struct btrfs_stream_header hdr;
u64 errors = 0;
int last_err = 0;
sctx.fd = fd;
sctx.ops = ops;
sctx.user = user;
sctx.stream_pos = 0;
ret = read_buf(&sctx, (char*)&hdr, sizeof(hdr));
if (ret < 0)
goto out;
if (ret) {
ret = -ENODATA;
goto out;
}
if (strcmp(hdr.magic, BTRFS_SEND_STREAM_MAGIC)) {
ret = -EINVAL;
error("unexpected header");
goto out;
}
sctx.version = le32_to_cpu(hdr.version);
if (sctx.version > BTRFS_SEND_STREAM_VERSION) {
ret = -EINVAL;
error("stream version %d not supported, please use newer version",
sctx.version);
goto out;
}
while (1) {
ret = read_and_process_cmd(&sctx);
if (ret < 0) {
last_err = ret;
errors++;
if (max_errors > 0 && errors >= max_errors)
goto out;
} else if (ret > 0) {
if (!honor_end_cmd)
ret = 0;
goto out;
}
}
out:
if (last_err && !ret)
ret = last_err;
return ret;
}