1 /*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /*
18 * Most of this code comes from bsdiff.c from the bsdiff-4.3
19 * distribution, which is:
20 */
21
22 /*-
23 * Copyright 2003-2005 Colin Percival
24 * All rights reserved
25 *
26 * Redistribution and use in source and binary forms, with or without
27 * modification, are permitted providing that the following conditions
28 * are met:
29 * 1. Redistributions of source code must retain the above copyright
30 * notice, this list of conditions and the following disclaimer.
31 * 2. Redistributions in binary form must reproduce the above copyright
32 * notice, this list of conditions and the following disclaimer in the
33 * documentation and/or other materials provided with the distribution.
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
36 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
37 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
38 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
39 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
40 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
41 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
42 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
43 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
44 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
45 * POSSIBILITY OF SUCH DAMAGE.
46 */
47
48 #include <sys/types.h>
49
50 #include <bzlib.h>
51 #include <err.h>
52 #include <fcntl.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <unistd.h>
57
58 #define MIN(x,y) (((x)<(y)) ? (x) : (y))
59
split(off_t * I,off_t * V,off_t start,off_t len,off_t h)60 static void split(off_t *I,off_t *V,off_t start,off_t len,off_t h)
61 {
62 off_t i,j,k,x,tmp,jj,kk;
63
64 if(len<16) {
65 for(k=start;k<start+len;k+=j) {
66 j=1;x=V[I[k]+h];
67 for(i=1;k+i<start+len;i++) {
68 if(V[I[k+i]+h]<x) {
69 x=V[I[k+i]+h];
70 j=0;
71 };
72 if(V[I[k+i]+h]==x) {
73 tmp=I[k+j];I[k+j]=I[k+i];I[k+i]=tmp;
74 j++;
75 };
76 };
77 for(i=0;i<j;i++) V[I[k+i]]=k+j-1;
78 if(j==1) I[k]=-1;
79 };
80 return;
81 };
82
83 x=V[I[start+len/2]+h];
84 jj=0;kk=0;
85 for(i=start;i<start+len;i++) {
86 if(V[I[i]+h]<x) jj++;
87 if(V[I[i]+h]==x) kk++;
88 };
89 jj+=start;kk+=jj;
90
91 i=start;j=0;k=0;
92 while(i<jj) {
93 if(V[I[i]+h]<x) {
94 i++;
95 } else if(V[I[i]+h]==x) {
96 tmp=I[i];I[i]=I[jj+j];I[jj+j]=tmp;
97 j++;
98 } else {
99 tmp=I[i];I[i]=I[kk+k];I[kk+k]=tmp;
100 k++;
101 };
102 };
103
104 while(jj+j<kk) {
105 if(V[I[jj+j]+h]==x) {
106 j++;
107 } else {
108 tmp=I[jj+j];I[jj+j]=I[kk+k];I[kk+k]=tmp;
109 k++;
110 };
111 };
112
113 if(jj>start) split(I,V,start,jj-start,h);
114
115 for(i=0;i<kk-jj;i++) V[I[jj+i]]=kk-1;
116 if(jj==kk-1) I[jj]=-1;
117
118 if(start+len>kk) split(I,V,kk,start+len-kk,h);
119 }
120
qsufsort(off_t * I,off_t * V,u_char * old,off_t oldsize)121 static void qsufsort(off_t *I,off_t *V,u_char *old,off_t oldsize)
122 {
123 off_t buckets[256];
124 off_t i,h,len;
125
126 for(i=0;i<256;i++) buckets[i]=0;
127 for(i=0;i<oldsize;i++) buckets[old[i]]++;
128 for(i=1;i<256;i++) buckets[i]+=buckets[i-1];
129 for(i=255;i>0;i--) buckets[i]=buckets[i-1];
130 buckets[0]=0;
131
132 for(i=0;i<oldsize;i++) I[++buckets[old[i]]]=i;
133 I[0]=oldsize;
134 for(i=0;i<oldsize;i++) V[i]=buckets[old[i]];
135 V[oldsize]=0;
136 for(i=1;i<256;i++) if(buckets[i]==buckets[i-1]+1) I[buckets[i]]=-1;
137 I[0]=-1;
138
139 for(h=1;I[0]!=-(oldsize+1);h+=h) {
140 len=0;
141 for(i=0;i<oldsize+1;) {
142 if(I[i]<0) {
143 len-=I[i];
144 i-=I[i];
145 } else {
146 if(len) I[i-len]=-len;
147 len=V[I[i]]+1-i;
148 split(I,V,i,len,h);
149 i+=len;
150 len=0;
151 };
152 };
153 if(len) I[i-len]=-len;
154 };
155
156 for(i=0;i<oldsize+1;i++) I[V[i]]=i;
157 }
158
matchlen(u_char * old,off_t oldsize,u_char * new,off_t newsize)159 static off_t matchlen(u_char *old,off_t oldsize,u_char *new,off_t newsize)
160 {
161 off_t i;
162
163 for(i=0;(i<oldsize)&&(i<newsize);i++)
164 if(old[i]!=new[i]) break;
165
166 return i;
167 }
168
search(off_t * I,u_char * old,off_t oldsize,u_char * new,off_t newsize,off_t st,off_t en,off_t * pos)169 static off_t search(off_t *I,u_char *old,off_t oldsize,
170 u_char *new,off_t newsize,off_t st,off_t en,off_t *pos)
171 {
172 off_t x,y;
173
174 if(en-st<2) {
175 x=matchlen(old+I[st],oldsize-I[st],new,newsize);
176 y=matchlen(old+I[en],oldsize-I[en],new,newsize);
177
178 if(x>y) {
179 *pos=I[st];
180 return x;
181 } else {
182 *pos=I[en];
183 return y;
184 }
185 };
186
187 x=st+(en-st)/2;
188 if(memcmp(old+I[x],new,MIN(oldsize-I[x],newsize))<0) {
189 return search(I,old,oldsize,new,newsize,x,en,pos);
190 } else {
191 return search(I,old,oldsize,new,newsize,st,x,pos);
192 };
193 }
194
offtout(off_t x,u_char * buf)195 static void offtout(off_t x,u_char *buf)
196 {
197 off_t y;
198
199 if(x<0) y=-x; else y=x;
200
201 buf[0]=y%256;y-=buf[0];
202 y=y/256;buf[1]=y%256;y-=buf[1];
203 y=y/256;buf[2]=y%256;y-=buf[2];
204 y=y/256;buf[3]=y%256;y-=buf[3];
205 y=y/256;buf[4]=y%256;y-=buf[4];
206 y=y/256;buf[5]=y%256;y-=buf[5];
207 y=y/256;buf[6]=y%256;y-=buf[6];
208 y=y/256;buf[7]=y%256;
209
210 if(x<0) buf[7]|=0x80;
211 }
212
213 // This is main() from bsdiff.c, with the following changes:
214 //
215 // - old, oldsize, new, newsize are arguments; we don't load this
216 // data from files. old and new are owned by the caller; we
217 // don't free them at the end.
218 //
219 // - the "I" block of memory is owned by the caller, who passes a
220 // pointer to *I, which can be NULL. This way if we call
221 // bsdiff() multiple times with the same 'old' data, we only do
222 // the qsufsort() step the first time.
223 //
bsdiff(u_char * old,off_t oldsize,off_t ** IP,u_char * new,off_t newsize,const char * patch_filename)224 int bsdiff(u_char* old, off_t oldsize, off_t** IP, u_char* new, off_t newsize,
225 const char* patch_filename)
226 {
227 int fd;
228 off_t *I;
229 off_t scan,pos,len;
230 off_t lastscan,lastpos,lastoffset;
231 off_t oldscore,scsc;
232 off_t s,Sf,lenf,Sb,lenb;
233 off_t overlap,Ss,lens;
234 off_t i;
235 off_t dblen,eblen;
236 u_char *db,*eb;
237 u_char buf[8];
238 u_char header[32];
239 FILE * pf;
240 BZFILE * pfbz2;
241 int bz2err;
242
243 if (*IP == NULL) {
244 off_t* V;
245 *IP = malloc((oldsize+1) * sizeof(off_t));
246 V = malloc((oldsize+1) * sizeof(off_t));
247 qsufsort(*IP, V, old, oldsize);
248 free(V);
249 }
250 I = *IP;
251
252 if(((db=malloc(newsize+1))==NULL) ||
253 ((eb=malloc(newsize+1))==NULL)) err(1,NULL);
254 dblen=0;
255 eblen=0;
256
257 /* Create the patch file */
258 if ((pf = fopen(patch_filename, "w")) == NULL)
259 err(1, "%s", patch_filename);
260
261 /* Header is
262 0 8 "BSDIFF40"
263 8 8 length of bzip2ed ctrl block
264 16 8 length of bzip2ed diff block
265 24 8 length of new file */
266 /* File is
267 0 32 Header
268 32 ?? Bzip2ed ctrl block
269 ?? ?? Bzip2ed diff block
270 ?? ?? Bzip2ed extra block */
271 memcpy(header,"BSDIFF40",8);
272 offtout(0, header + 8);
273 offtout(0, header + 16);
274 offtout(newsize, header + 24);
275 if (fwrite(header, 32, 1, pf) != 1)
276 err(1, "fwrite(%s)", patch_filename);
277
278 /* Compute the differences, writing ctrl as we go */
279 if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
280 errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
281 scan=0;len=0;
282 lastscan=0;lastpos=0;lastoffset=0;
283 while(scan<newsize) {
284 oldscore=0;
285
286 for(scsc=scan+=len;scan<newsize;scan++) {
287 len=search(I,old,oldsize,new+scan,newsize-scan,
288 0,oldsize,&pos);
289
290 for(;scsc<scan+len;scsc++)
291 if((scsc+lastoffset<oldsize) &&
292 (old[scsc+lastoffset] == new[scsc]))
293 oldscore++;
294
295 if(((len==oldscore) && (len!=0)) ||
296 (len>oldscore+8)) break;
297
298 if((scan+lastoffset<oldsize) &&
299 (old[scan+lastoffset] == new[scan]))
300 oldscore--;
301 };
302
303 if((len!=oldscore) || (scan==newsize)) {
304 s=0;Sf=0;lenf=0;
305 for(i=0;(lastscan+i<scan)&&(lastpos+i<oldsize);) {
306 if(old[lastpos+i]==new[lastscan+i]) s++;
307 i++;
308 if(s*2-i>Sf*2-lenf) { Sf=s; lenf=i; };
309 };
310
311 lenb=0;
312 if(scan<newsize) {
313 s=0;Sb=0;
314 for(i=1;(scan>=lastscan+i)&&(pos>=i);i++) {
315 if(old[pos-i]==new[scan-i]) s++;
316 if(s*2-i>Sb*2-lenb) { Sb=s; lenb=i; };
317 };
318 };
319
320 if(lastscan+lenf>scan-lenb) {
321 overlap=(lastscan+lenf)-(scan-lenb);
322 s=0;Ss=0;lens=0;
323 for(i=0;i<overlap;i++) {
324 if(new[lastscan+lenf-overlap+i]==
325 old[lastpos+lenf-overlap+i]) s++;
326 if(new[scan-lenb+i]==
327 old[pos-lenb+i]) s--;
328 if(s>Ss) { Ss=s; lens=i+1; };
329 };
330
331 lenf+=lens-overlap;
332 lenb-=lens;
333 };
334
335 for(i=0;i<lenf;i++)
336 db[dblen+i]=new[lastscan+i]-old[lastpos+i];
337 for(i=0;i<(scan-lenb)-(lastscan+lenf);i++)
338 eb[eblen+i]=new[lastscan+lenf+i];
339
340 dblen+=lenf;
341 eblen+=(scan-lenb)-(lastscan+lenf);
342
343 offtout(lenf,buf);
344 BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
345 if (bz2err != BZ_OK)
346 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
347
348 offtout((scan-lenb)-(lastscan+lenf),buf);
349 BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
350 if (bz2err != BZ_OK)
351 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
352
353 offtout((pos-lenb)-(lastpos+lenf),buf);
354 BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
355 if (bz2err != BZ_OK)
356 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
357
358 lastscan=scan-lenb;
359 lastpos=pos-lenb;
360 lastoffset=pos-scan;
361 };
362 };
363 BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
364 if (bz2err != BZ_OK)
365 errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
366
367 /* Compute size of compressed ctrl data */
368 if ((len = ftello(pf)) == -1)
369 err(1, "ftello");
370 offtout(len-32, header + 8);
371
372 /* Write compressed diff data */
373 if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
374 errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
375 BZ2_bzWrite(&bz2err, pfbz2, db, dblen);
376 if (bz2err != BZ_OK)
377 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
378 BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
379 if (bz2err != BZ_OK)
380 errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
381
382 /* Compute size of compressed diff data */
383 if ((newsize = ftello(pf)) == -1)
384 err(1, "ftello");
385 offtout(newsize - len, header + 16);
386
387 /* Write compressed extra data */
388 if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
389 errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
390 BZ2_bzWrite(&bz2err, pfbz2, eb, eblen);
391 if (bz2err != BZ_OK)
392 errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
393 BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
394 if (bz2err != BZ_OK)
395 errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
396
397 /* Seek to the beginning, write the header, and close the file */
398 if (fseeko(pf, 0, SEEK_SET))
399 err(1, "fseeko");
400 if (fwrite(header, 32, 1, pf) != 1)
401 err(1, "fwrite(%s)", patch_filename);
402 if (fclose(pf))
403 err(1, "fclose");
404
405 /* Free the memory we used */
406 free(db);
407 free(eb);
408
409 return 0;
410 }
411