ref: e51c4bc6e493a9cd0d9e9d7f1d24c57ae77bab65
dir: /sys/src/cmd/venti/srv/reseal.c/
#include "stdinc.h"
#include "dat.h"
#include "fns.h"
static uchar *data;
static uchar *data1;
static int blocksize;
static int sleepms;
static int fd;
static int force;
static vlong offset0;
void
usage(void)
{
fprint(2, "usage: reseal [-f] [-b blocksize] [-s ms] arenapart1 [name...]]\n");
threadexitsall(0);
}
static int
pwriteblock(uchar *buf, int n, vlong off)
{
int nr, m;
for(nr = 0; nr < n; nr += m){
m = n - nr;
m = pwrite(fd, &buf[nr], m, offset0+off+nr);
if(m <= 0)
return -1;
}
return 0;
}
static int
preadblock(uchar *buf, int n, vlong off)
{
int nr, m;
for(nr = 0; nr < n; nr += m){
m = n - nr;
m = pread(fd, &buf[nr], m, offset0+off+nr);
if(m <= 0){
if(m == 0)
werrstr("early eof");
return -1;
}
}
return 0;
}
static int
loadheader(char *name, ArenaHead *head, Arena *arena, vlong off)
{
if(preadblock(data, head->blocksize, off + head->size - head->blocksize) < 0){
fprint(2, "%s: reading arena tail: %r\n", name);
return -1;
}
memset(arena, 0, sizeof *arena);
if(unpackarena(arena, data) < 0){
fprint(2, "%s: unpack arena tail: %r\n", name);
return -1;
}
arena->blocksize = head->blocksize;
arena->base = off + head->blocksize;
arena->clumpmax = arena->blocksize / ClumpInfoSize;
arena->size = head->size - 2*head->blocksize;
if(arena->diskstats.sealed)
scorecp(arena->score, data + head->blocksize - VtScoreSize);
return 0;
}
uchar zero[VtScoreSize];
static int
verify(Arena *arena, void *data, uchar *newscore)
{
vlong e, bs, n, o;
DigestState ds, ds1;
uchar score[VtScoreSize];
/*
* now we know how much to read
* read everything but the last block, which is special
*/
e = arena->size + arena->blocksize;
o = arena->base - arena->blocksize;
bs = arena->blocksize;
memset(&ds, 0, sizeof ds);
for(n = 0; n < e; n += bs){
if(preadblock(data, bs, o + n) < 0){
werrstr("read: %r");
return -1;
}
if(n + bs > e)
bs = e - n;
sha1(data, bs, nil, &ds);
}
/* last block */
if(preadblock(data, arena->blocksize, o + e) < 0){
werrstr("read: %r");
return -1;
}
ds1 = ds;
sha1(data, bs - VtScoreSize, nil, &ds);
sha1(zero, VtScoreSize, score, &ds);
if(scorecmp(score, arena->score) != 0){
if(!force){
werrstr("score mismatch: %V != %V", score, arena->score);
return -1;
}
fprint(2, "warning: score mismatch %V != %V\n", score, arena->score);
}
/* prepare new last block */
memset(data, 0, arena->blocksize);
packarena(arena, data);
sha1(data, bs, newscore, &ds1);
scorecp((uchar*)data + arena->blocksize - VtScoreSize, newscore);
return 0;
}
static void
resealarena(char *name, vlong len)
{
ArenaHead head;
Arena arena;
DigestState s;
u64int off;
uchar newscore[VtScoreSize];
fprint(2, "%s: begin reseal\n", name);
memset(&s, 0, sizeof s);
off = seek(fd, 0, 1);
/*
* read a little bit, which will include the header
*/
if(preadblock(data, HeadSize, off) < 0){
fprint(2, "%s: reading header: %r\n", name);
return;
}
if(unpackarenahead(&head, data) < 0){
fprint(2, "%s: corrupt arena header: %r\n", name);
return;
}
if(head.version != ArenaVersion4 && head.version != ArenaVersion5)
fprint(2, "%s: warning: unknown arena version %d\n", name, head.version);
if(len != 0 && len != head.size)
fprint(2, "%s: warning: unexpected length %lld != %lld\n", name, head.size, len);
if(strcmp(name, "<stdin>") != 0 && strcmp(head.name, name) != 0)
fprint(2, "%s: warning: unexpected name %s\n", name, head.name);
if(loadheader(name, &head, &arena, off) < 0)
return;
if(!arena.diskstats.sealed){
fprint(2, "%s: not sealed\n", name);
return;
}
if(verify(&arena, data, newscore) < 0){
fprint(2, "%s: failed to verify before reseal: %r\n", name);
return;
}
if(pwriteblock(data, arena.blocksize, arena.base + arena.size) < 0){
fprint(2, "%s: writing new tail: %r\n", name);
return;
}
scorecp(arena.score, newscore);
fprint(2, "%s: resealed: %V\n", name, newscore);
if(verify(&arena, data, newscore) < 0){
fprint(2, "%s: failed to verify after reseal!: %r\n", name);
return;
}
fprint(2, "%s: verified: %V\n", name, newscore);
}
static int
shouldcheck(char *name, char **s, int n)
{
int i;
if(n == 0)
return 1;
for(i=0; i<n; i++){
if(s[i] && strcmp(name, s[i]) == 0){
s[i] = nil;
return 1;
}
}
return 0;
}
char *
readap(ArenaPart *ap)
{
char *table;
if(preadblock(data, 8192, PartBlank) < 0)
sysfatal("read arena part header: %r");
if(unpackarenapart(ap, data) < 0)
sysfatal("corrupted arena part header: %r");
fprint(2, "# arena part version=%d blocksize=%d arenabase=%d\n",
ap->version, ap->blocksize, ap->arenabase);
ap->tabbase = (PartBlank+HeadSize+ap->blocksize-1)&~(ap->blocksize-1);
ap->tabsize = ap->arenabase - ap->tabbase;
table = malloc(ap->tabsize+1);
if(preadblock((uchar*)table, ap->tabsize, ap->tabbase) < 0)
sysfatal("reading arena part directory: %r");
table[ap->tabsize] = 0;
return table;
}
void
threadmain(int argc, char *argv[])
{
int i, nline;
char *p, *q, *table, *f[10], line[256];
vlong start, stop;
ArenaPart ap;
Part *part;
ventifmtinstall();
blocksize = MaxIoSize;
ARGBEGIN{
case 'b':
blocksize = unittoull(EARGF(usage()));
break;
case 'f':
force = 1;
break;
case 's':
sleepms = atoi(EARGF(usage()));
break;
default:
usage();
break;
}ARGEND
if(argc < 2)
usage();
data = vtmalloc(blocksize);
if((part = initpart(argv[0], ORDWR)) == nil)
sysfatal("open partition %s: %r", argv[0]);
fd = part->fd;
offset0 = part->offset;
table = readap(&ap);
nline = atoi(table);
p = strchr(table, '\n');
if(p)
p++;
for(i=0; i<nline; i++){
if(p == nil){
fprint(2, "warning: unexpected arena table end\n");
break;
}
q = strchr(p, '\n');
if(q)
*q++ = 0;
if(strlen(p) >= sizeof line){
fprint(2, "warning: long arena table line: %s\n", p);
p = q;
continue;
}
strcpy(line, p);
memset(f, 0, sizeof f);
if(tokenize(line, f, nelem(f)) < 3){
fprint(2, "warning: bad arena table line: %s\n", p);
p = q;
continue;
}
p = q;
if(shouldcheck(f[0], argv+1, argc-1)){
start = strtoull(f[1], 0, 0);
stop = strtoull(f[2], 0, 0);
if(stop <= start){
fprint(2, "%s: bad start,stop %lld,%lld\n", f[0], stop, start);
continue;
}
if(seek(fd, start, 0) < 0)
fprint(2, "%s: seek to start: %r\n", f[0]);
resealarena(f[0], stop - start);
}
}
for(i=2; i<argc; i++)
if(argv[i] != 0)
fprint(2, "%s: did not find arena\n", argv[i]);
threadexitsall(nil);
}