diff options
Diffstat (limited to 'src/cmd/venti/srv/reseal.c')
| -rw-r--r-- | src/cmd/venti/srv/reseal.c | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/src/cmd/venti/srv/reseal.c b/src/cmd/venti/srv/reseal.c new file mode 100644 index 00000000..144e640f --- /dev/null +++ b/src/cmd/venti/srv/reseal.c @@ -0,0 +1,314 @@ +#include "stdinc.h" +#include "dat.h" +#include "fns.h" + +static int verbose; +static int fd; +static uchar *data; +static uchar *data1; +static int blocksize; +static int sleepms; + +void +usage(void) +{ + fprint(2, "usage: reseal [-b blocksize] [-s ms] [-v] arenapart1 [name...]]\n"); + threadexitsall(0); +} + +static int +pwriteblock(int fd, 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, off+nr); + if(m <= 0) + return -1; + } + return 0; +} + +static int +preadblock(int fd, 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, off+nr); + if(m <= 0){ + if(m == 0) + werrstr("early eof"); + return -1; + } + } + return 0; +} + +static int +readblock(int fd, uchar *buf, int n) +{ + int nr, m; + + for(nr = 0; nr < n; nr += m){ + m = n - nr; + m = read(fd, &buf[nr], m); + if(m <= 0){ + if(m == 0) + werrstr("early eof"); + return -1; + } + } + return 0; +} + +static int +loadheader(char *name, ArenaHead *head, Arena *arena, int fd, vlong off) +{ + if(preadblock(fd, 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(int fd, 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(fd, 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(fd, 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){ + werrstr("score mismatch: %V != %V", score, arena->score); + return -1; + } + + /* 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(fd, 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, fd, off) < 0) + return; + + if(!arena.diskstats.sealed){ + fprint(2, "%s: not sealed\n", name); + return; + } + + if(verify(fd, &arena, data, newscore) < 0){ + fprint(2, "%s: failed to verify before reseal: %r\n", name); + return; + } + fprint(2, "%s: verified: %V\n", name, arena.score); + + if(pwriteblock(fd, 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(fd, &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(int fd, ArenaPart *ap) +{ + char *table; + + if(preadblock(fd, 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(fd, (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; + + ventifmtinstall(); + blocksize = MaxIoSize; + ARGBEGIN{ + case 'b': + blocksize = unittoull(EARGF(usage())); + break; + case 's': + sleepms = atoi(EARGF(usage())); + break; + case 'v': + verbose++; + break; + default: + usage(); + break; + }ARGEND + + if(argc < 2) + usage(); + + data = vtmalloc(blocksize); + if((fd = open(argv[0], ORDWR)) < 0) + sysfatal("open %s: %r", argv[0]); + + table = readap(fd, &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); +} |