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freebsd-nq/sbin/dump/traverse.c

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/*-
* Copyright (c) 1980, 1988, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)traverse.c 8.7 (Berkeley) 6/15/95";
#endif
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/param.h>
#include <sys/stat.h>
#include <ufs/ufs/dir.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>
#include <protocols/dumprestore.h>
#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <timeconv.h>
#include <unistd.h>
#include "dump.h"
union dinode {
struct ufs1_dinode dp1;
struct ufs2_dinode dp2;
};
#define DIP(dp, field) \
((sblock->fs_magic == FS_UFS1_MAGIC) ? \
(dp)->dp1.field : (dp)->dp2.field)
#define DIP_SET(dp, field, val) do {\
if (sblock->fs_magic == FS_UFS1_MAGIC) \
(dp)->dp1.field = (val); \
else \
(dp)->dp2.field = (val); \
} while (0)
#define HASDUMPEDFILE 0x1
#define HASSUBDIRS 0x2
static int dirindir(ino_t ino, ufs2_daddr_t blkno, int level, long *size,
long *tapesize, int nodump);
static void dmpindir(ino_t ino, ufs2_daddr_t blk, int level, off_t *size);
static int searchdir(ino_t ino, ufs2_daddr_t blkno, long size, long filesize,
long *tapesize, int nodump);
static long blockest(union dinode *dp);
/*
* This is an estimation of the number of TP_BSIZE blocks in the file.
* It estimates the number of blocks in files with holes by assuming
* that all of the blocks accounted for by di_blocks are data blocks
* (when some of the blocks are usually used for indirect pointers);
* hence the estimate may be high.
*/
static long
blockest(union dinode *dp)
{
long blkest, sizeest;
/*
* dp->di_size is the size of the file in bytes.
* dp->di_blocks stores the number of sectors actually in the file.
* If there are more sectors than the size would indicate, this just
* means that there are indirect blocks in the file or unused
* sectors in the last file block; we can safely ignore these
* (blkest = sizeest below).
* If the file is bigger than the number of sectors would indicate,
* then the file has holes in it. In this case we must use the
* block count to estimate the number of data blocks used, but
* we use the actual size for estimating the number of indirect
* dump blocks (sizeest vs. blkest in the indirect block
* calculation).
*/
if ((DIP(dp, di_flags) & SF_SNAPSHOT) != 0)
return (1);
blkest = howmany(dbtob(DIP(dp, di_blocks)), TP_BSIZE);
sizeest = howmany(DIP(dp, di_size), TP_BSIZE);
if (blkest > sizeest)
blkest = sizeest;
if (DIP(dp, di_size) > sblock->fs_bsize * NDADDR) {
/* calculate the number of indirect blocks on the dump tape */
blkest +=
howmany(sizeest - NDADDR * sblock->fs_bsize / TP_BSIZE,
TP_NINDIR);
}
return (blkest + 1);
}
/* Auxiliary macro to pick up files changed since previous dump. */
#define CHANGEDSINCE(dp, t) \
(DIP(dp, di_mtime) >= (t) || DIP(dp, di_ctime) >= (t))
/* The WANTTODUMP macro decides whether a file should be dumped. */
#ifdef UF_NODUMP
#define WANTTODUMP(dp) \
(CHANGEDSINCE(dp, spcl.c_ddate) && \
(nonodump || (DIP(dp, di_flags) & UF_NODUMP) != UF_NODUMP))
#else
#define WANTTODUMP(dp) CHANGEDSINCE(dp, spcl.c_ddate)
#endif
/*
* Dump pass 1.
*
* Walk the inode list for a file system to find all allocated inodes
* that have been modified since the previous dump time. Also, find all
* the directories in the file system.
*/
int
mapfiles(ino_t maxino, long *tapesize)
{
int i, cg, mode, inosused;
int anydirskipped = 0;
union dinode *dp;
struct cg *cgp;
ino_t ino;
u_char *cp;
if ((cgp = malloc(sblock->fs_cgsize)) == NULL)
quit("mapfiles: cannot allocate memory.\n");
for (cg = 0; cg < sblock->fs_ncg; cg++) {
ino = cg * sblock->fs_ipg;
bread(fsbtodb(sblock, cgtod(sblock, cg)), (char *)cgp,
sblock->fs_cgsize);
if (sblock->fs_magic == FS_UFS2_MAGIC)
inosused = cgp->cg_initediblk;
else
inosused = sblock->fs_ipg;
/*
* If we are using soft updates, then we can trust the
* cylinder group inode allocation maps to tell us which
* inodes are allocated. We will scan the used inode map
* to find the inodes that are really in use, and then
* read only those inodes in from disk.
*/
if (sblock->fs_flags & FS_DOSOFTDEP) {
if (!cg_chkmagic(cgp))
quit("mapfiles: cg %d: bad magic number\n", cg);
cp = &cg_inosused(cgp)[(inosused - 1) / CHAR_BIT];
for ( ; inosused > 0; inosused -= CHAR_BIT, cp--) {
if (*cp == 0)
continue;
for (i = 1 << (CHAR_BIT - 1); i > 0; i >>= 1) {
if (*cp & i)
break;
inosused--;
}
break;
}
if (inosused <= 0)
continue;
}
for (i = 0; i < inosused; i++, ino++) {
if (ino < ROOTINO ||
(dp = getino(ino, &mode)) == NULL ||
(mode & IFMT) == 0)
continue;
/*
* Everything must go in usedinomap so that a check
* for "in dumpdirmap but not in usedinomap" to detect
* dirs with nodump set has a chance of succeeding
* (this is used in mapdirs()).
*/
SETINO(ino, usedinomap);
if (mode == IFDIR)
SETINO(ino, dumpdirmap);
if (WANTTODUMP(dp)) {
SETINO(ino, dumpinomap);
if (mode != IFREG &&
mode != IFDIR &&
mode != IFLNK)
*tapesize += 1;
else
*tapesize += blockest(dp);
continue;
}
if (mode == IFDIR) {
if (!nonodump &&
(DIP(dp, di_flags) & UF_NODUMP))
CLRINO(ino, usedinomap);
anydirskipped = 1;
}
}
}
/*
* Restore gets very upset if the root is not dumped,
* so ensure that it always is dumped.
*/
SETINO(ROOTINO, dumpinomap);
return (anydirskipped);
}
/*
* Dump pass 2.
*
* Scan each directory on the file system to see if it has any modified
* files in it. If it does, and has not already been added to the dump
* list (because it was itself modified), then add it. If a directory
* has not been modified itself, contains no modified files and has no
* subdirectories, then it can be deleted from the dump list and from
* the list of directories. By deleting it from the list of directories,
* its parent may now qualify for the same treatment on this or a later
* pass using this algorithm.
*/
int
mapdirs(ino_t maxino, long *tapesize)
{
union dinode *dp;
int i, isdir, nodump;
char *map;
ino_t ino;
union dinode di;
long filesize;
int ret, change = 0;
isdir = 0; /* XXX just to get gcc to shut up */
for (map = dumpdirmap, ino = 1; ino < maxino; ino++) {
if (((ino - 1) % CHAR_BIT) == 0) /* map is offset by 1 */
isdir = *map++;
else
isdir >>= 1;
/*
* If a directory has been removed from usedinomap, it
* either has the nodump flag set, or has inherited
* it. Although a directory can't be in dumpinomap if
* it isn't in usedinomap, we have to go through it to
* propagate the nodump flag.
*/
nodump = !nonodump && (TSTINO(ino, usedinomap) == 0);
if ((isdir & 1) == 0 || (TSTINO(ino, dumpinomap) && !nodump))
continue;
dp = getino(ino, &i);
/*
* inode buf may change in searchdir().
*/
if (sblock->fs_magic == FS_UFS1_MAGIC)
di.dp1 = dp->dp1;
else
di.dp2 = dp->dp2;
filesize = DIP(&di, di_size);
for (ret = 0, i = 0; filesize > 0 && i < NDADDR; i++) {
if (DIP(&di, di_db[i]) != 0)
ret |= searchdir(ino, DIP(&di, di_db[i]),
(long)sblksize(sblock, DIP(&di, di_size),
i), filesize, tapesize, nodump);
if (ret & HASDUMPEDFILE)
filesize = 0;
else
filesize -= sblock->fs_bsize;
}
for (i = 0; filesize > 0 && i < NIADDR; i++) {
if (DIP(&di, di_ib[i]) == 0)
continue;
ret |= dirindir(ino, DIP(&di, di_ib[i]), i, &filesize,
tapesize, nodump);
}
if (ret & HASDUMPEDFILE) {
SETINO(ino, dumpinomap);
*tapesize += blockest(&di);
change = 1;
continue;
}
if (nodump) {
if (ret & HASSUBDIRS)
change = 1; /* subdirs inherit nodump */
CLRINO(ino, dumpdirmap);
} else if ((ret & HASSUBDIRS) == 0)
if (!TSTINO(ino, dumpinomap)) {
CLRINO(ino, dumpdirmap);
change = 1;
}
}
return (change);
}
/*
* Read indirect blocks, and pass the data blocks to be searched
* as directories. Quit as soon as any entry is found that will
* require the directory to be dumped.
*/
static int
dirindir(
ino_t ino,
ufs2_daddr_t blkno,
int ind_level,
long *filesize,
long *tapesize,
int nodump)
{
union {
ufs1_daddr_t ufs1[MAXBSIZE / sizeof(ufs1_daddr_t)];
ufs2_daddr_t ufs2[MAXBSIZE / sizeof(ufs2_daddr_t)];
} idblk;
int ret = 0;
int i;
bread(fsbtodb(sblock, blkno), (char *)&idblk, (int)sblock->fs_bsize);
if (ind_level <= 0) {
for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
if (sblock->fs_magic == FS_UFS1_MAGIC)
blkno = idblk.ufs1[i];
else
blkno = idblk.ufs2[i];
if (blkno != 0)
ret |= searchdir(ino, blkno, sblock->fs_bsize,
*filesize, tapesize, nodump);
if (ret & HASDUMPEDFILE)
*filesize = 0;
else
*filesize -= sblock->fs_bsize;
}
return (ret);
}
ind_level--;
for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
if (sblock->fs_magic == FS_UFS1_MAGIC)
blkno = idblk.ufs1[i];
else
blkno = idblk.ufs2[i];
if (blkno != 0)
ret |= dirindir(ino, blkno, ind_level, filesize,
tapesize, nodump);
}
return (ret);
}
/*
* Scan a disk block containing directory information looking to see if
* any of the entries are on the dump list and to see if the directory
* contains any subdirectories.
*/
static int
searchdir(
ino_t ino,
ufs2_daddr_t blkno,
long size,
long filesize,
long *tapesize,
int nodump)
{
int mode;
struct direct *dp;
union dinode *ip;
long loc, ret = 0;
static caddr_t dblk;
if (dblk == NULL && (dblk = malloc(sblock->fs_bsize)) == NULL)
quit("searchdir: cannot allocate indirect memory.\n");
bread(fsbtodb(sblock, blkno), dblk, (int)size);
if (filesize < size)
size = filesize;
for (loc = 0; loc < size; ) {
dp = (struct direct *)(dblk + loc);
if (dp->d_reclen == 0) {
msg("corrupted directory, inumber %d\n", ino);
break;
}
loc += dp->d_reclen;
if (dp->d_ino == 0)
continue;
if (dp->d_name[0] == '.') {
if (dp->d_name[1] == '\0')
continue;
if (dp->d_name[1] == '.' && dp->d_name[2] == '\0')
continue;
}
if (nodump) {
ip = getino(dp->d_ino, &mode);
if (TSTINO(dp->d_ino, dumpinomap)) {
CLRINO(dp->d_ino, dumpinomap);
*tapesize -= blockest(ip);
}
/*
* Add back to dumpdirmap and remove from usedinomap
* to propagate nodump.
*/
if (mode == IFDIR) {
SETINO(dp->d_ino, dumpdirmap);
CLRINO(dp->d_ino, usedinomap);
ret |= HASSUBDIRS;
}
} else {
if (TSTINO(dp->d_ino, dumpinomap)) {
ret |= HASDUMPEDFILE;
if (ret & HASSUBDIRS)
break;
}
if (TSTINO(dp->d_ino, dumpdirmap)) {
ret |= HASSUBDIRS;
if (ret & HASDUMPEDFILE)
break;
}
}
}
return (ret);
}
/*
* Dump passes 3 and 4.
*
* Dump the contents of an inode to tape.
*/
void
dumpino(union dinode *dp, ino_t ino)
{
int ind_level, cnt;
off_t size;
char buf[TP_BSIZE];
if (newtape) {
newtape = 0;
dumpmap(dumpinomap, TS_BITS, ino);
}
CLRINO(ino, dumpinomap);
/*
* Zero out the size of a snapshot so that it will be dumped
* as a zero length file.
*/
if ((DIP(dp, di_flags) & SF_SNAPSHOT) != 0) {
DIP_SET(dp, di_size, 0);
DIP_SET(dp, di_flags, DIP(dp, di_flags) & ~SF_SNAPSHOT);
}
if (sblock->fs_magic == FS_UFS1_MAGIC) {
spcl.c_mode = dp->dp1.di_mode;
spcl.c_size = dp->dp1.di_size;
spcl.c_atime = _time32_to_time(dp->dp1.di_atime);
spcl.c_atimensec = dp->dp1.di_atimensec;
spcl.c_mtime = _time32_to_time(dp->dp1.di_mtime);
spcl.c_mtimensec = dp->dp1.di_mtimensec;
spcl.c_birthtime = 0;
spcl.c_birthtimensec = 0;
spcl.c_rdev = dp->dp1.di_rdev;
spcl.c_file_flags = dp->dp1.di_flags;
spcl.c_uid = dp->dp1.di_uid;
spcl.c_gid = dp->dp1.di_gid;
} else {
spcl.c_mode = dp->dp2.di_mode;
spcl.c_size = dp->dp2.di_size;
spcl.c_atime = _time64_to_time(dp->dp2.di_atime);
spcl.c_atimensec = dp->dp2.di_atimensec;
spcl.c_mtime = _time64_to_time(dp->dp2.di_mtime);
spcl.c_mtimensec = dp->dp2.di_mtimensec;
spcl.c_birthtime = _time64_to_time(dp->dp2.di_birthtime);
spcl.c_birthtimensec = dp->dp2.di_birthnsec;
spcl.c_rdev = dp->dp2.di_rdev;
spcl.c_file_flags = dp->dp2.di_flags;
spcl.c_uid = dp->dp2.di_uid;
spcl.c_gid = dp->dp2.di_gid;
}
spcl.c_type = TS_INODE;
spcl.c_count = 0;
switch (DIP(dp, di_mode) & S_IFMT) {
case 0:
/*
* Freed inode.
*/
return;
case S_IFLNK:
/*
* Check for short symbolic link.
*/
if (DIP(dp, di_size) > 0 &&
DIP(dp, di_size) < sblock->fs_maxsymlinklen) {
spcl.c_addr[0] = 1;
spcl.c_count = 1;
writeheader(ino);
if (sblock->fs_magic == FS_UFS1_MAGIC)
memmove(buf, (caddr_t)dp->dp1.di_db,
(u_long)DIP(dp, di_size));
else
memmove(buf, (caddr_t)dp->dp2.di_db,
(u_long)DIP(dp, di_size));
buf[DIP(dp, di_size)] = '\0';
writerec(buf, 0);
return;
}
/* FALLTHROUGH */
case S_IFDIR:
case S_IFREG:
if (DIP(dp, di_size) > 0)
break;
/* FALLTHROUGH */
case S_IFIFO:
case S_IFSOCK:
case S_IFCHR:
case S_IFBLK:
writeheader(ino);
return;
default:
msg("Warning: undefined file type 0%o\n",
DIP(dp, di_mode) & IFMT);
return;
}
if (DIP(dp, di_size) > NDADDR * sblock->fs_bsize)
cnt = NDADDR * sblock->fs_frag;
else
cnt = howmany(DIP(dp, di_size), sblock->fs_fsize);
if (sblock->fs_magic == FS_UFS1_MAGIC)
ufs1_blksout(&dp->dp1.di_db[0], cnt, ino);
else
ufs2_blksout(&dp->dp2.di_db[0], cnt, ino);
if ((size = DIP(dp, di_size) - NDADDR * sblock->fs_bsize) <= 0)
return;
for (ind_level = 0; ind_level < NIADDR; ind_level++) {
dmpindir(ino, DIP(dp, di_ib[ind_level]), ind_level, &size);
if (size <= 0)
return;
}
}
/*
* Read indirect blocks, and pass the data blocks to be dumped.
*/
static void
dmpindir(ino_t ino, ufs2_daddr_t blk, int ind_level, off_t *size)
{
union {
ufs1_daddr_t ufs1[MAXBSIZE / sizeof(ufs1_daddr_t)];
ufs2_daddr_t ufs2[MAXBSIZE / sizeof(ufs2_daddr_t)];
} idblk;
int i, cnt;
if (blk != 0)
bread(fsbtodb(sblock, blk), (char *)&idblk,
(int)sblock->fs_bsize);
else
memset(&idblk, 0, sblock->fs_bsize);
if (ind_level <= 0) {
if (*size < NINDIR(sblock) * sblock->fs_bsize)
cnt = howmany(*size, sblock->fs_fsize);
else
cnt = NINDIR(sblock) * sblock->fs_frag;
*size -= NINDIR(sblock) * sblock->fs_bsize;
if (sblock->fs_magic == FS_UFS1_MAGIC)
ufs1_blksout(idblk.ufs1, cnt, ino);
else
ufs2_blksout(idblk.ufs2, cnt, ino);
return;
}
ind_level--;
for (i = 0; i < NINDIR(sblock); i++) {
if (sblock->fs_magic == FS_UFS1_MAGIC)
dmpindir(ino, idblk.ufs1[i], ind_level, size);
else
dmpindir(ino, idblk.ufs2[i], ind_level, size);
if (*size <= 0)
return;
}
}
/*
* Collect up the data into tape record sized buffers and output them.
*/
void
ufs1_blksout(ufs1_daddr_t *blkp, int frags, ino_t ino)
{
ufs1_daddr_t *bp;
int i, j, count, blks, tbperdb;
blks = howmany(frags * sblock->fs_fsize, TP_BSIZE);
tbperdb = sblock->fs_bsize >> tp_bshift;
for (i = 0; i < blks; i += TP_NINDIR) {
if (i + TP_NINDIR > blks)
count = blks;
else
count = i + TP_NINDIR;
for (j = i; j < count; j++)
if (blkp[j / tbperdb] != 0)
spcl.c_addr[j - i] = 1;
else
spcl.c_addr[j - i] = 0;
spcl.c_count = count - i;
writeheader(ino);
bp = &blkp[i / tbperdb];
for (j = i; j < count; j += tbperdb, bp++)
if (*bp != 0) {
if (j + tbperdb <= count)
dumpblock(*bp, (int)sblock->fs_bsize);
else
dumpblock(*bp, (count - j) * TP_BSIZE);
}
spcl.c_type = TS_ADDR;
}
}
/*
* Collect up the data into tape record sized buffers and output them.
*/
void
ufs2_blksout(ufs2_daddr_t *blkp, int frags, ino_t ino)
{
ufs2_daddr_t *bp;
int i, j, count, blks, tbperdb;
blks = howmany(frags * sblock->fs_fsize, TP_BSIZE);
tbperdb = sblock->fs_bsize >> tp_bshift;
for (i = 0; i < blks; i += TP_NINDIR) {
if (i + TP_NINDIR > blks)
count = blks;
else
count = i + TP_NINDIR;
for (j = i; j < count; j++)
if (blkp[j / tbperdb] != 0)
spcl.c_addr[j - i] = 1;
else
spcl.c_addr[j - i] = 0;
spcl.c_count = count - i;
writeheader(ino);
bp = &blkp[i / tbperdb];
for (j = i; j < count; j += tbperdb, bp++)
if (*bp != 0) {
if (j + tbperdb <= count)
dumpblock(*bp, (int)sblock->fs_bsize);
else
dumpblock(*bp, (count - j) * TP_BSIZE);
}
spcl.c_type = TS_ADDR;
}
}
/*
* Dump a map to the tape.
*/
void
dumpmap(char *map, int type, ino_t ino)
{
int i;
char *cp;
spcl.c_type = type;
spcl.c_count = howmany(mapsize * sizeof(char), TP_BSIZE);
writeheader(ino);
for (i = 0, cp = map; i < spcl.c_count; i++, cp += TP_BSIZE)
writerec(cp, 0);
}
/*
* Write a header record to the dump tape.
*/
void
writeheader(ino_t ino)
{
int32_t sum, cnt, *lp;
spcl.c_inumber = ino;
spcl.c_magic = FS_UFS2_MAGIC;
spcl.c_checksum = 0;
lp = (int32_t *)&spcl;
sum = 0;
cnt = sizeof(union u_spcl) / (4 * sizeof(int32_t));
while (--cnt >= 0) {
sum += *lp++;
sum += *lp++;
sum += *lp++;
sum += *lp++;
}
spcl.c_checksum = CHECKSUM - sum;
writerec((char *)&spcl, 1);
}
union dinode *
getino(ino_t inum, int *modep)
{
static ino_t minino, maxino;
static caddr_t inoblock;
struct ufs1_dinode *dp1;
struct ufs2_dinode *dp2;
if (inoblock == NULL && (inoblock = malloc(sblock->fs_bsize)) == NULL)
quit("cannot allocate inode memory.\n");
curino = inum;
if (inum >= minino && inum < maxino)
goto gotit;
bread(fsbtodb(sblock, ino_to_fsba(sblock, inum)), inoblock,
(int)sblock->fs_bsize);
minino = inum - (inum % INOPB(sblock));
maxino = minino + INOPB(sblock);
gotit:
if (sblock->fs_magic == FS_UFS1_MAGIC) {
dp1 = &((struct ufs1_dinode *)inoblock)[inum - minino];
*modep = (dp1->di_mode & IFMT);
return ((union dinode *)dp1);
}
dp2 = &((struct ufs2_dinode *)inoblock)[inum - minino];
*modep = (dp2->di_mode & IFMT);
return ((union dinode *)dp2);
}
/*
* Read a chunk of data from the disk.
* Try to recover from hard errors by reading in sector sized pieces.
* Error recovery is attempted at most BREADEMAX times before seeking
* consent from the operator to continue.
*/
int breaderrors = 0;
#define BREADEMAX 32
void
bread(ufs2_daddr_t blkno, char *buf, int size)
{
int secsize, bytes, resid, xfer, base, cnt, i;
static char *tmpbuf;
off_t offset;
loop:
offset = blkno << dev_bshift;
secsize = sblock->fs_fsize;
base = offset % secsize;
resid = size % secsize;
/*
* If the transfer request starts or ends on a non-sector
* boundary, we must read the entire sector and copy out
* just the part that we need.
*/
if (base == 0 && resid == 0) {
cnt = cread(diskfd, buf, size, offset);
if (cnt == size)
return;
} else {
if (tmpbuf == NULL && (tmpbuf = malloc(secsize)) == 0)
quit("buffer malloc failed\n");
xfer = 0;
bytes = size;
if (base != 0) {
cnt = cread(diskfd, tmpbuf, secsize, offset - base);
if (cnt != secsize)
goto bad;
xfer = secsize - base;
offset += xfer;
bytes -= xfer;
resid = bytes % secsize;
memcpy(buf, &tmpbuf[base], xfer);
}
if (bytes >= secsize) {
cnt = cread(diskfd, &buf[xfer], bytes - resid, offset);
if (cnt != bytes - resid)
goto bad;
xfer += cnt;
offset += cnt;
}
if (resid == 0)
return;
cnt = cread(diskfd, tmpbuf, secsize, offset);
if (cnt == secsize) {
memcpy(&buf[xfer], tmpbuf, resid);
return;
}
}
bad:
if (blkno + (size / dev_bsize) > fsbtodb(sblock, sblock->fs_size)) {
/*
* Trying to read the final fragment.
*
* NB - dump only works in TP_BSIZE blocks, hence
* rounds `dev_bsize' fragments up to TP_BSIZE pieces.
* It should be smarter about not actually trying to
* read more than it can get, but for the time being
* we punt and scale back the read only when it gets
* us into trouble. (mkm 9/25/83)
*/
size -= dev_bsize;
goto loop;
}
if (cnt == -1)
msg("read error from %s: %s: [block %jd]: count=%d\n",
disk, strerror(errno), (intmax_t)blkno, size);
else
msg("short read error from %s: [block %jd]: count=%d, got=%d\n",
disk, (intmax_t)blkno, size, cnt);
if (++breaderrors > BREADEMAX) {
msg("More than %d block read errors from %s\n",
BREADEMAX, disk);
broadcast("DUMP IS AILING!\n");
msg("This is an unrecoverable error.\n");
if (!query("Do you want to attempt to continue?")){
dumpabort(0);
/*NOTREACHED*/
} else
breaderrors = 0;
}
/*
* Zero buffer, then try to read each sector of buffer separately,
* and bypass the cache.
*/
memset(buf, 0, size);
for (i = 0; i < size; i += dev_bsize, buf += dev_bsize, blkno++) {
if ((cnt = pread(diskfd, buf, (int)dev_bsize,
((off_t)blkno << dev_bshift))) == dev_bsize)
continue;
if (cnt == -1) {
msg("read error from %s: %s: [sector %jd]: count=%ld\n",
disk, strerror(errno), (intmax_t)blkno, dev_bsize);
continue;
}
msg("short read from %s: [sector %jd]: count=%ld, got=%d\n",
disk, (intmax_t)blkno, dev_bsize, cnt);
}
}
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