Line data Source code
1 : #include "../../burp.h"
2 : #include "rabin.h"
3 : #include "rconf.h"
4 : #include "win.h"
5 : #include "../../alloc.h"
6 : #include "../blk.h"
7 : #include "../blist.h"
8 : #include "../../sbuf.h"
9 :
10 : static struct blk *blk=NULL;
11 : static char *gcp=NULL;
12 : static char *gbuf=NULL;
13 : static char *gbuf_end=NULL;
14 : static struct rconf rconf;
15 : static struct win *win=NULL; // Rabin sliding window.
16 : static int first=0;
17 :
18 3 : int blks_generate_init(void)
19 : {
20 3 : rconf_init(&rconf);
21 9 : if(!(win=win_alloc(&rconf))
22 6 : || !(gbuf=(char *)malloc_w(rconf.blk_max, __func__)))
23 0 : return -1;
24 3 : gbuf_end=gbuf;
25 3 : gcp=gbuf;
26 3 : return 0;
27 : }
28 :
29 4 : void blks_generate_free(void)
30 : {
31 4 : free_w(&gbuf);
32 4 : win_free(&win);
33 4 : }
34 :
35 : // This is where the magic happens.
36 : // Return 1 for got a block, 0 for no block got.
37 0 : static int blk_read(void)
38 : {
39 : char c;
40 :
41 0 : for(; gcp<gbuf_end; gcp++)
42 : {
43 0 : c=*gcp;
44 :
45 0 : blk->fingerprint = (blk->fingerprint * rconf.prime) + c;
46 0 : win->checksum = (win->checksum * rconf.prime) + c
47 0 : - (win->data[win->pos] * rconf.multiplier);
48 0 : win->data[win->pos] = c;
49 :
50 0 : win->pos++;
51 0 : if(blk->data) blk->data[blk->length] = c;
52 0 : blk->length++;
53 :
54 0 : if(win->pos == rconf.win_size) win->pos=0;
55 :
56 0 : if( blk->length >= rconf.blk_min
57 0 : && (blk->length == rconf.blk_max
58 0 : || (win->checksum % rconf.blk_avg) == rconf.prime))
59 : {
60 0 : gcp++;
61 0 : return 1;
62 : }
63 : }
64 0 : return 0;
65 : }
66 :
67 0 : static int blk_read_to_list(struct sbuf *sb, struct blist *blist)
68 : {
69 0 : if(!blk_read()) return 0;
70 :
71 : // Got something.
72 0 : if(first)
73 : {
74 0 : sb->protocol2->bstart=blk;
75 0 : first=0;
76 : }
77 0 : if(!sb->protocol2->bsighead)
78 : {
79 0 : sb->protocol2->bsighead=blk;
80 : }
81 0 : blist_add_blk(blist, blk);
82 0 : blk=NULL;
83 0 : return 1;
84 : }
85 :
86 : // The client uses this.
87 1 : int blks_generate(struct asfd *asfd, struct conf **confs,
88 : struct sbuf *sb, struct blist *blist)
89 : {
90 : static ssize_t bytes;
91 :
92 1 : if(sb->protocol2->bfd.mode==BF_CLOSED)
93 : {
94 1 : struct cntr *cntr=NULL;
95 1 : if(confs) cntr=get_cntr(confs);
96 1 : if(sbuf_open_file(sb, asfd, cntr, confs)) return -1;
97 0 : first=1;
98 : }
99 :
100 0 : if(!blk && !(blk=blk_alloc_with_data(rconf.blk_max)))
101 0 : return -1;
102 :
103 0 : if(gcp<gbuf_end)
104 : {
105 : // Could have got a fill before buf ran out -
106 : // need to resume from the same place in that case.
107 0 : if(blk_read_to_list(sb, blist))
108 0 : return 0; // Got a block.
109 : // Did not get a block. Carry on and read more.
110 : }
111 0 : while((bytes=sbuf_read(sb, gbuf, rconf.blk_max)))
112 : {
113 0 : gcp=gbuf;
114 0 : gbuf_end=gbuf+bytes;
115 0 : sb->protocol2->bytes_read+=bytes;
116 0 : if(blk_read_to_list(sb, blist))
117 0 : return 0; // Got a block
118 : // Did not get a block. Maybe should try again?
119 : // If there are async timeouts, look at this!
120 0 : return 0;
121 : }
122 :
123 : // Getting here means there is no more to read from the file.
124 : // Make sure to deal with anything left over.
125 :
126 0 : if(!sb->protocol2->bytes_read)
127 : {
128 : // Empty file, set up an empty block so that the server
129 : // can skip over it.
130 0 : if(!(sb->protocol2->bstart=blk_alloc())) return -1;
131 0 : sb->protocol2->bsighead=blk;
132 0 : blist_add_blk(blist, blk);
133 0 : blk=NULL;
134 : }
135 0 : else if(blk)
136 : {
137 0 : if(blk->length)
138 : {
139 0 : if(first)
140 : {
141 0 : sb->protocol2->bstart=blk;
142 0 : first=0;
143 : }
144 0 : if(!sb->protocol2->bsighead)
145 : {
146 0 : sb->protocol2->bsighead=blk;
147 : }
148 0 : blist_add_blk(blist, blk);
149 : }
150 0 : else blk_free(&blk);
151 0 : blk=NULL;
152 : }
153 0 : if(blist->tail) sb->protocol2->bend=blist->tail;
154 0 : sbuf_close_file(sb, asfd);
155 0 : return 0;
156 : }
157 :
158 : // The server uses this for verification.
159 0 : int blk_read_verify(struct blk *blk_to_verify)
160 : {
161 0 : if(!win)
162 : {
163 0 : rconf_init(&rconf);
164 0 : if(!(win=win_alloc(&rconf))) return -1;
165 : }
166 :
167 0 : gbuf=blk_to_verify->data;
168 0 : gbuf_end=gbuf+blk_to_verify->length;
169 0 : gcp=gbuf;
170 0 : if(!blk && !(blk=blk_alloc())) return -1;
171 0 : blk->length=0;
172 0 : blk->fingerprint=0;
173 :
174 : // FIX THIS: blk_read should return 1 when it has a block.
175 : // But, if the block is too small (because the end of the file
176 : // happened), it returns 0, and blks_generate treats it as having found
177 : // a final block.
178 : // So, here the return of blk_read is ignored and we look at the
179 : // position of gcp instead.
180 0 : blk_read();
181 0 : if(gcp==gbuf_end
182 0 : && blk->fingerprint==blk_to_verify->fingerprint)
183 0 : return 1;
184 0 : return 0;
185 : }
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