freebsd-nq/lib/libufs/libufs.h

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2002 Juli Mallett. All rights reserved.
*
* This software was written by Juli Mallett <jmallett@FreeBSD.org> for the
* FreeBSD project. Redistribution and use in source and binary forms, with
* or without modification, are permitted provided that the following
* conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef __LIBUFS_H__
#define __LIBUFS_H__
/*
* libufs structures.
*/
union dinodep {
struct ufs1_dinode *dp1;
struct ufs2_dinode *dp2;
};
/*
* userland ufs disk.
*/
struct uufsd {
const char *d_name; /* disk name */
int d_ufs; /* decimal UFS version */
int d_fd; /* raw device file descriptor */
long d_bsize; /* device bsize */
ufs2_daddr_t d_sblock; /* superblock location */
struct fs_summary_info *d_si; /* Superblock summary info */
caddr_t d_inoblock; /* inode block */
uint32_t d_inomin; /* low ino, not ino_t for ABI compat */
uint32_t d_inomax; /* high ino, not ino_t for ABI compat */
union dinodep d_dp; /* pointer to currently active inode */
union {
struct fs d_fs; /* filesystem information */
char d_sb[MAXBSIZE]; /* superblock as buffer */
} d_sbunion;
union {
struct cg d_cg; /* cylinder group */
char d_buf[MAXBSIZE]; /* cylinder group storage */
} d_cgunion;
int d_ccg; /* current cylinder group */
int d_lcg; /* last cylinder group (in d_cg) */
const char *d_error; /* human readable disk error */
int d_mine; /* internal flags */
#define d_fs d_sbunion.d_fs
#define d_sb d_sbunion.d_sb
#define d_cg d_cgunion.d_cg
};
/*
* libufs macros (internal, non-exported).
*/
#ifdef _LIBUFS
/*
* Trace steps through libufs, to be used at entry and erroneous return.
*/
static inline void
ERROR(struct uufsd *u, const char *str)
{
#ifdef _LIBUFS_DEBUGGING
if (str != NULL) {
fprintf(stderr, "libufs: %s", str);
if (errno != 0)
fprintf(stderr, ": %s", strerror(errno));
fprintf(stderr, "\n");
}
#endif
if (u != NULL)
u->d_error = str;
}
#endif /* _LIBUFS */
__BEGIN_DECLS
/*
* libufs prototypes.
*/
/*
* ffs_subr.c
*/
void ffs_clrblock(struct fs *, u_char *, ufs1_daddr_t);
void ffs_clusteracct(struct fs *, struct cg *, ufs1_daddr_t, int);
void ffs_fragacct(struct fs *, int, int32_t [], int);
int ffs_isblock(struct fs *, u_char *, ufs1_daddr_t);
int ffs_isfreeblock(struct fs *, u_char *, ufs1_daddr_t);
void ffs_setblock(struct fs *, u_char *, ufs1_daddr_t);
int ffs_sbget(void *, struct fs **, off_t, char *,
int (*)(void *, off_t, void **, int));
int ffs_sbput(void *, struct fs *, off_t,
int (*)(void *, off_t, void *, int));
void ffs_update_dinode_ckhash(struct fs *, struct ufs2_dinode *);
int ffs_verify_dinode_ckhash(struct fs *, struct ufs2_dinode *);
Normally when an attempt is made to mount a UFS/FFS filesystem whose superblock has a check-hash error, an error message noting the superblock check-hash failure is printed and the mount fails. The administrator then runs fsck to repair the filesystem and when successful, the filesystem can once again be mounted. This approach fails if the filesystem in question is a root filesystem from which you are trying to boot. Here, the loader fails when trying to access the filesystem to get the kernel to boot. So it is necessary to allow the loader to ignore the superblock check-hash error and make a best effort to read the kernel. The filesystem may be suffiently corrupted that the read attempt fails, but there is no harm in trying since the loader makes no attempt to write to the filesystem. Once the kernel is loaded and starts to run, it attempts to mount its root filesystem. Once again, failure means that it breaks to its prompt to ask where to get its root filesystem. Unless you have an alternate root filesystem, you are stuck. Since the root filesystem is initially mounted read-only, it is safe to make an attempt to mount the root filesystem with the failed superblock check-hash. Thus, when asked to mount a root filesystem with a failed superblock check-hash, the kernel prints a warning message that the root filesystem superblock check-hash needs repair, but notes that it is ignoring the error and proceeding. It does mark the filesystem as needing an fsck which prevents it from being enabled for writing until fsck has been run on it. The net effect is that the reboot fails to single user, but at least at that point the administrator has the tools at hand to fix the problem. Reported by: Rick Macklem (rmacklem@) Discussed with: Warner Losh (imp@) Sponsored by: Netflix
2018-12-06 00:09:39 +00:00
/*
* Request standard superblock location in ffs_sbget
*/
#define STDSB -1 /* Fail if check-hash is bad */
#define STDSB_NOHASHFAIL -2 /* Ignore check-hash failure */
/*
* block.c
*/
ssize_t bread(struct uufsd *, ufs2_daddr_t, void *, size_t);
ssize_t bwrite(struct uufsd *, ufs2_daddr_t, const void *, size_t);
int berase(struct uufsd *, ufs2_daddr_t, ufs2_daddr_t);
/*
* cgroup.c
*/
ufs2_daddr_t cgballoc(struct uufsd *);
int cgbfree(struct uufsd *, ufs2_daddr_t, long);
ino_t cgialloc(struct uufsd *);
int cgget(int, struct fs *, int, struct cg *);
int cgput(int, struct fs *, struct cg *);
int cgread(struct uufsd *);
int cgread1(struct uufsd *, int);
int cgwrite(struct uufsd *);
int cgwrite1(struct uufsd *, int);
/*
* inode.c
*/
int getinode(struct uufsd *, union dinodep *, ino_t);
int putinode(struct uufsd *);
/*
* sblock.c
*/
int sbread(struct uufsd *);
int sbwrite(struct uufsd *, int);
/* low level superblock read/write functions */
int sbget(int, struct fs **, off_t);
int sbput(int, struct fs *, int);
/*
* type.c
*/
int ufs_disk_close(struct uufsd *);
int ufs_disk_fillout(struct uufsd *, const char *);
int ufs_disk_fillout_blank(struct uufsd *, const char *);
int ufs_disk_write(struct uufsd *);
Continuing efforts to provide hardening of FFS, this change adds a check hash to cylinder groups. If a check hash fails when a cylinder group is read, no further allocations are attempted in that cylinder group until it has been fixed by fsck. This avoids a class of filesystem panics related to corrupted cylinder group maps. The hash is done using crc32c. Check hases are added only to UFS2 and not to UFS1 as UFS1 is primarily used in embedded systems with small memories and low-powered processors which need as light-weight a filesystem as possible. Specifics of the changes: sys/sys/buf.h: Add BX_FSPRIV to reserve a set of eight b_xflags that may be used by individual filesystems for their own purpose. Their specific definitions are found in the header files for each filesystem that uses them. Also add fields to struct buf as noted below. sys/kern/vfs_bio.c: It is only necessary to compute a check hash for a cylinder group when it is actually read from disk. When calling bread, you do not know whether the buffer was found in the cache or read. So a new flag (GB_CKHASH) and a pointer to a function to perform the hash has been added to breadn_flags to say that the function should be called to calculate a hash if the data has been read. The check hash is placed in b_ckhash and the B_CKHASH flag is set to indicate that a read was done and a check hash calculated. Though a rather elaborate mechanism, it should also work for check hashing other metadata in the future. A kernel internal API change was to change breada into a static fucntion and add flags and a function pointer to a check-hash function. sys/ufs/ffs/fs.h: Add flags for types of check hashes; stored in a new word in the superblock. Define corresponding BX_ flags for the different types of check hashes. Add a check hash word in the cylinder group. sys/ufs/ffs/ffs_alloc.c: In ffs_getcg do the dance with breadn_flags to get a check hash and if one is provided, check it. sys/ufs/ffs/ffs_vfsops.c: Copy across the BX_FFSTYPES flags in background writes. Update the check hash when writing out buffers that need them. sys/ufs/ffs/ffs_snapshot.c: Recompute check hash when updating snapshot cylinder groups. sys/libkern/crc32.c: lib/libufs/Makefile: lib/libufs/libufs.h: lib/libufs/cgroup.c: Include libkern/crc32.c in libufs and use it to compute check hashes when updating cylinder groups. Four utilities are affected: sbin/newfs/mkfs.c: Add the check hashes when building the cylinder groups. sbin/fsck_ffs/fsck.h: sbin/fsck_ffs/fsutil.c: Verify and update check hashes when checking and writing cylinder groups. sbin/fsck_ffs/pass5.c: Offer to add check hashes to existing filesystems. Precompute check hashes when rebuilding cylinder group (although this will be done when it is written in fsutil.c it is necessary to do it early before comparing with the old cylinder group) sbin/dumpfs/dumpfs.c Print out the new check hash flag(s) sbin/fsdb/Makefile: Needs to add libufs now used by pass5.c imported from fsck_ffs. Reviewed by: kib Tested by: Peter Holm (pho)
2017-09-22 12:45:15 +00:00
/*
* crc32c.c
*/
uint32_t calculate_crc32c(uint32_t, const void *, size_t);
__END_DECLS
#endif /* __LIBUFS_H__ */