1 #include "stdinc.h"
2 #include "dat.h"
3 #include "fns.h"
4 
5 static int	verbose;
6 
7 void
8 usage(void)
9 {
10 	fprint(2, "usage: verifyarena [-v]\n");
11 	threadexitsall(0);
12 }
13 
14 static void
15 readblock(uchar *buf, int n)
16 {
17 	int nr, m;
18 
19 	for(nr = 0; nr < n; nr += m){
20 		m = n - nr;
21 		m = read(0, &buf[nr], m);
22 		if(m <= 0)
23 			sysfatal("can't read arena from standard input: %r");
24 	}
25 }
26 
27 static void
28 verifyarena(void)
29 {
30 	Arena arena;
31 	ArenaHead head;
32 	ZBlock *b;
33 	DigestState s;
34 	u64int n, e;
35 	u32int bs;
36 	u8int score[VtScoreSize];
37 
38 	fprint(2, "verify arena from standard input\n");
39 
40 	memset(&arena, 0, sizeof arena);
41 	memset(&s, 0, sizeof s);
42 
43 	/*
44 	 * read the little bit, which will included the header
45 	 */
46 	bs = MaxIoSize;
47 	b = alloczblock(bs, 0);
48 	readblock(b->data, HeadSize);
49 	sha1(b->data, HeadSize, nil, &s);
50 	if(unpackarenahead(&head, b->data) < 0)
51 		sysfatal("corrupted arena header: %r");
52 	if(head.version != ArenaVersion)
53 		fprint(2, "warning: unknown arena version %d\n", head.version);
54 
55 	/*
56 	 * now we know how much to read
57 	 * read everything but the last block, which is special
58 	 */
59 	e = head.size - head.blocksize;
60 	for(n = HeadSize; n < e; n += bs){
61 		if(n + bs > e)
62 			bs = e - n;
63 		readblock(b->data, bs);
64 		sha1(b->data, bs, nil, &s);
65 	}
66 
67 	/*
68 	 * read the last block update the sum.
69 	 * the sum is calculated assuming the slot for the sum is zero.
70 	 */
71 	bs = head.blocksize;
72 	readblock(b->data, bs);
73 	sha1(b->data, bs-VtScoreSize, nil, &s);
74 	sha1(zeroscore, VtScoreSize, nil, &s);
75 	sha1(nil, 0, score, &s);
76 
77 	/*
78 	 * validity check on the trailer
79 	 */
80 	arena.blocksize = head.blocksize;
81 	if(unpackarena(&arena, b->data) < 0)
82 		sysfatal("corrupted arena trailer: %r");
83 	scorecp(arena.score, &b->data[arena.blocksize - VtScoreSize]);
84 
85 	if(namecmp(arena.name, head.name) != 0)
86 		sysfatal("arena header and trailer names clash: %s vs. %s\n", head.name, arena.name);
87 	if(arena.version != head.version)
88 		sysfatal("arena header and trailer versions clash: %d vs. %d\n", head.version, arena.version);
89 	arena.size = head.size - 2 * head.blocksize;
90 
91 	/*
92 	 * check for no checksum or the same
93 	 */
94 	if(scorecmp(score, arena.score) != 0){
95 		if(scorecmp(zeroscore, arena.score) != 0)
96 			fprint(2, "warning: mismatched checksums for arena=%s, found=%V calculated=%V",
97 				arena.name, arena.score, score);
98 		scorecp(arena.score, score);
99 	}else
100 		fprint(2, "matched score\n");
101 
102 	printarena(2, &arena);
103 }
104 
105 void
106 threadmain(int argc, char *argv[])
107 {
108 	fmtinstall('V', vtscorefmt);
109 	statsinit();
110 
111 	ARGBEGIN{
112 	case 'v':
113 		verbose++;
114 		break;
115 	default:
116 		usage();
117 		break;
118 	}ARGEND
119 
120 	readonly = 1;
121 
122 	if(argc != 0)
123 		usage();
124 
125 	verifyarena();
126 	threadexitsall(0);
127 }