treseal.c - plan9port - [fork] Plan 9 from user space
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treseal.c (6512B)
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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 }