1 #include "stdinc.h"
2 #include "dat.h"
3 #include "fns.h"
4 
5 static uchar	*data;
6 static uchar	*data1;
7 static int	blocksize;
8 static int	sleepms;
9 static int	fd;
10 static int	force;
11 static vlong	offset0;
12 
13 void
14 usage(void)
15 {
16 	fprint(2, "usage: reseal [-f] [-b blocksize] [-s ms] arenapart1 [name...]]\n");
17 	threadexitsall(0);
18 }
19 
20 static int
21 pwriteblock(uchar *buf, int n, vlong off)
22 {
23 	int nr, m;
24 
25 	for(nr = 0; nr < n; nr += m){
26 		m = n - nr;
27 		m = pwrite(fd, &buf[nr], m, offset0+off+nr);
28 		if(m <= 0)
29 			return -1;
30 	}
31 	return 0;
32 }
33 
34 static int
35 preadblock(uchar *buf, int n, vlong off)
36 {
37 	int nr, m;
38 
39 	for(nr = 0; nr < n; nr += m){
40 		m = n - nr;
41 		m = pread(fd, &buf[nr], m, offset0+off+nr);
42 		if(m <= 0){
43 			if(m == 0)
44 				werrstr("early eof");
45 			return -1;
46 		}
47 	}
48 	return 0;
49 }
50 
51 static int
52 loadheader(char *name, ArenaHead *head, Arena *arena, vlong off)
53 {
54 	if(preadblock(data, head->blocksize, off + head->size - head->blocksize) < 0){
55 		fprint(2, "%s: reading arena tail: %r\n", name);
56 		return -1;
57 	}
58 
59 	memset(arena, 0, sizeof *arena);
60 	if(unpackarena(arena, data) < 0){
61 		fprint(2, "%s: unpack arena tail: %r\n", name);
62 		return -1;
63 	}
64 	arena->blocksize = head->blocksize;
65 	arena->base = off + head->blocksize;
66 	arena->clumpmax = arena->blocksize / ClumpInfoSize;
67 	arena->size = head->size - 2*head->blocksize;
68 
69 	if(arena->diskstats.sealed)
70 		scorecp(arena->score, data + head->blocksize - VtScoreSize);
71 	return 0;
72 }
73 
74 uchar zero[VtScoreSize];
75 
76 static int
77 verify(Arena *arena, void *data, uchar *newscore)
78 {
79 	vlong e, bs, n, o;
80 	DigestState ds, ds1;
81 	uchar score[VtScoreSize];
82 
83 	/*
84 	 * now we know how much to read
85 	 * read everything but the last block, which is special
86 	 */
87 	e = arena->size + arena->blocksize;
88 	o = arena->base - arena->blocksize;
89 	bs = arena->blocksize;
90 	memset(&ds, 0, sizeof ds);
91 	for(n = 0; n < e; n += bs){
92 		if(preadblock(data, bs, o + n) < 0){
93 			werrstr("read: %r");
94 			return -1;
95 		}
96 		if(n + bs > e)
97 			bs = e - n;
98 		sha1(data, bs, nil, &ds);
99 	}
100 
101 	/* last block */
102 	if(preadblock(data, arena->blocksize, o + e) < 0){
103 		werrstr("read: %r");
104 		return -1;
105 	}
106 	ds1 = ds;
107 	sha1(data, bs - VtScoreSize, nil, &ds);
108 	sha1(zero, VtScoreSize, score, &ds);
109 	if(scorecmp(score, arena->score) != 0){
110 		if(!force){
111 			werrstr("score mismatch: %V != %V", score, arena->score);
112 			return -1;
113 		}
114 		fprint(2, "warning: score mismatch %V != %V\n", score, arena->score);
115 	}
116 
117 	/* prepare new last block */
118 	memset(data, 0, arena->blocksize);
119 	packarena(arena, data);
120 	sha1(data, bs, newscore, &ds1);
121 	scorecp((uchar*)data + arena->blocksize - VtScoreSize, newscore);
122 
123 	return 0;
124 }
125 
126 static void
127 resealarena(char *name, vlong len)
128 {
129 	ArenaHead head;
130 	Arena arena;
131 	DigestState s;
132 	u64int off;
133 	uchar newscore[VtScoreSize];
134 
135 	fprint(2, "%s: begin reseal\n", name);
136 
137 	memset(&s, 0, sizeof s);
138 
139 	off = seek(fd, 0, 1);
140 
141 	/*
142 	 * read a little bit, which will include the header
143 	 */
144 	if(preadblock(data, HeadSize, off) < 0){
145 		fprint(2, "%s: reading header: %r\n", name);
146 		return;
147 	}
148 	if(unpackarenahead(&head, data) < 0){
149 		fprint(2, "%s: corrupt arena header: %r\n", name);
150 		return;
151 	}
152 	if(head.version != ArenaVersion4 && head.version != ArenaVersion5)
153 		fprint(2, "%s: warning: unknown arena version %d\n", name, head.version);
154 	if(len != 0 && len != head.size)
155 		fprint(2, "%s: warning: unexpected length %lld != %lld\n", name, head.size, len);
156 	if(strcmp(name, "<stdin>") != 0 && strcmp(head.name, name) != 0)
157 		fprint(2, "%s: warning: unexpected name %s\n", name, head.name);
158 
159 	if(loadheader(name, &head, &arena, off) < 0)
160 		return;
161 
162 	if(!arena.diskstats.sealed){
163 		fprint(2, "%s: not sealed\n", name);
164 		return;
165 	}
166 
167 	if(verify(&arena, data, newscore) < 0){
168 		fprint(2, "%s: failed to verify before reseal: %r\n", name);
169 		return;
170 	}
171 
172 	if(pwriteblock(data, arena.blocksize, arena.base + arena.size) < 0){
173 		fprint(2, "%s: writing new tail: %r\n", name);
174 		return;
175 	}
176 	scorecp(arena.score, newscore);
177 	fprint(2, "%s: resealed: %V\n", name, newscore);
178 
179 	if(verify(&arena, data, newscore) < 0){
180 		fprint(2, "%s: failed to verify after reseal!: %r\n", name);
181 		return;
182 	}
183 
184 	fprint(2, "%s: verified: %V\n", name, newscore);
185 }
186 
187 static int
188 shouldcheck(char *name, char **s, int n)
189 {
190 	int i;
191 
192 	if(n == 0)
193 		return 1;
194 
195 	for(i=0; i<n; i++){
196 		if(s[i] && strcmp(name, s[i]) == 0){
197 			s[i] = nil;
198 			return 1;
199 		}
200 	}
201 	return 0;
202 }
203 
204 char *
205 readap(ArenaPart *ap)
206 {
207 	char *table;
208 
209 	if(preadblock(data, 8192, PartBlank) < 0)
210 		sysfatal("read arena part header: %r");
211 	if(unpackarenapart(ap, data) < 0)
212 		sysfatal("corrupted arena part header: %r");
213 	fprint(2, "# arena part version=%d blocksize=%d arenabase=%d\n",
214 		ap->version, ap->blocksize, ap->arenabase);
215 	ap->tabbase = (PartBlank+HeadSize+ap->blocksize-1)&~(ap->blocksize-1);
216 	ap->tabsize = ap->arenabase - ap->tabbase;
217 	table = malloc(ap->tabsize+1);
218 	if(preadblock((uchar*)table, ap->tabsize, ap->tabbase) < 0)
219 		sysfatal("reading arena part directory: %r");
220 	table[ap->tabsize] = 0;
221 	return table;
222 }
223 
224 void
225 threadmain(int argc, char *argv[])
226 {
227 	int i, nline;
228 	char *p, *q, *table, *f[10], line[256];
229 	vlong start, stop;
230 	ArenaPart ap;
231 	Part *part;
232 
233 	ventifmtinstall();
234 	blocksize = MaxIoSize;
235 	ARGBEGIN{
236 	case 'b':
237 		blocksize = unittoull(EARGF(usage()));
238 		break;
239 	case 'f':
240 		force = 1;
241 		break;
242 	case 's':
243 		sleepms = atoi(EARGF(usage()));
244 		break;
245 	default:
246 		usage();
247 		break;
248 	}ARGEND
249 
250 	if(argc < 2)
251 		usage();
252 
253 	data = vtmalloc(blocksize);
254 	if((part = initpart(argv[0], ORDWR)) == nil)
255 		sysfatal("open partition %s: %r", argv[0]);
256 	fd = part->fd;
257 	offset0 = part->offset;
258 
259 	table = readap(&ap);
260 
261 	nline = atoi(table);
262 	p = strchr(table, '\n');
263 	if(p)
264 		p++;
265 	for(i=0; i<nline; i++){
266 		if(p == nil){
267 			fprint(2, "warning: unexpected arena table end\n");
268 			break;
269 		}
270 		q = strchr(p, '\n');
271 		if(q)
272 			*q++ = 0;
273 		if(strlen(p) >= sizeof line){
274 			fprint(2, "warning: long arena table line: %s\n", p);
275 			p = q;
276 			continue;
277 		}
278 		strcpy(line, p);
279 		memset(f, 0, sizeof f);
280 		if(tokenize(line, f, nelem(f)) < 3){
281 			fprint(2, "warning: bad arena table line: %s\n", p);
282 			p = q;
283 			continue;
284 		}
285 		p = q;
286 		if(shouldcheck(f[0], argv+1, argc-1)){
287 			start = strtoull(f[1], 0, 0);
288 			stop = strtoull(f[2], 0, 0);
289 			if(stop <= start){
290 				fprint(2, "%s: bad start,stop %lld,%lld\n", f[0], stop, start);
291 				continue;
292 			}
293 			if(seek(fd, start, 0) < 0)
294 				fprint(2, "%s: seek to start: %r\n", f[0]);
295 			resealarena(f[0], stop - start);
296 		}
297 	}
298 	for(i=2; i<argc; i++)
299 		if(argv[i] != 0)
300 			fprint(2, "%s: did not find arena\n", argv[i]);
301 
302 	threadexitsall(nil);
303 }