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1 /*-
2  * Copyright 2003-2005 Colin Percival
3  * All rights reserved
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted providing that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
18  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
22  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
23  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
24  * POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #if 0
28 __FBSDID("$FreeBSD: src/usr.bin/bsdiff/bspatch/bspatch.c,v 1.1 2005/08/06 01:59:06 cperciva Exp $");
29 #endif
30 
31 #include <bzlib.h>
32 #include <stdlib.h>
33 #include <stdio.h>
34 #include <string.h>
35 #include <err.h>
36 #include <unistd.h>
37 #include <fcntl.h>
38 #include <sys/types.h>    // android
39 
offtin(u_char * buf)40 static off_t offtin(u_char *buf)
41 {
42 	off_t y;
43 
44 	y=buf[7]&0x7F;
45 	y=y*256;y+=buf[6];
46 	y=y*256;y+=buf[5];
47 	y=y*256;y+=buf[4];
48 	y=y*256;y+=buf[3];
49 	y=y*256;y+=buf[2];
50 	y=y*256;y+=buf[1];
51 	y=y*256;y+=buf[0];
52 
53 	if(buf[7]&0x80) y=-y;
54 
55 	return y;
56 }
57 
main(int argc,char * argv[])58 int main(int argc,char * argv[])
59 {
60 	FILE * f, * cpf, * dpf, * epf;
61 	BZFILE * cpfbz2, * dpfbz2, * epfbz2;
62 	int cbz2err, dbz2err, ebz2err;
63 	int fd;
64 	ssize_t oldsize,newsize;
65 	ssize_t bzctrllen,bzdatalen;
66 	u_char header[32],buf[8];
67 	u_char *old, *new;
68 	off_t oldpos,newpos;
69 	off_t ctrl[3];
70 	off_t lenread;
71 	off_t i;
72 
73 	if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
74 
75 	/* Open patch file */
76 	if ((f = fopen(argv[3], "r")) == NULL)
77 		err(1, "fopen(%s)", argv[3]);
78 
79 	/*
80 	File format:
81 		0	8	"BSDIFF40"
82 		8	8	X
83 		16	8	Y
84 		24	8	sizeof(newfile)
85 		32	X	bzip2(control block)
86 		32+X	Y	bzip2(diff block)
87 		32+X+Y	???	bzip2(extra block)
88 	with control block a set of triples (x,y,z) meaning "add x bytes
89 	from oldfile to x bytes from the diff block; copy y bytes from the
90 	extra block; seek forwards in oldfile by z bytes".
91 	*/
92 
93 	/* Read header */
94 	if (fread(header, 1, 32, f) < 32) {
95 		if (feof(f))
96 			errx(1, "Corrupt patch\n");
97 		err(1, "fread(%s)", argv[3]);
98 	}
99 
100 	/* Check for appropriate magic */
101 	if (memcmp(header, "BSDIFF40", 8) != 0)
102 		errx(1, "Corrupt patch\n");
103 
104 	/* Read lengths from header */
105 	bzctrllen=offtin(header+8);
106 	bzdatalen=offtin(header+16);
107 	newsize=offtin(header+24);
108 	if((bzctrllen<0) || (bzdatalen<0) || (newsize<0))
109 		errx(1,"Corrupt patch\n");
110 
111 	/* Close patch file and re-open it via libbzip2 at the right places */
112 	if (fclose(f))
113 		err(1, "fclose(%s)", argv[3]);
114 	if ((cpf = fopen(argv[3], "r")) == NULL)
115 		err(1, "fopen(%s)", argv[3]);
116 	if (fseeko(cpf, 32, SEEK_SET))
117 		err(1, "fseeko(%s, %lld)", argv[3],
118 		    (long long)32);
119 	if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
120 		errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
121 	if ((dpf = fopen(argv[3], "r")) == NULL)
122 		err(1, "fopen(%s)", argv[3]);
123 	if (fseeko(dpf, 32 + bzctrllen, SEEK_SET))
124 		err(1, "fseeko(%s, %lld)", argv[3],
125 		    (long long)(32 + bzctrllen));
126 	if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
127 		errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
128 	if ((epf = fopen(argv[3], "r")) == NULL)
129 		err(1, "fopen(%s)", argv[3]);
130 	if (fseeko(epf, 32 + bzctrllen + bzdatalen, SEEK_SET))
131 		err(1, "fseeko(%s, %lld)", argv[3],
132 		    (long long)(32 + bzctrllen + bzdatalen));
133 	if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
134 		errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
135 
136 	if(((fd=open(argv[1],O_RDONLY,0))<0) ||
137 		((oldsize=lseek(fd,0,SEEK_END))==-1) ||
138 		((old=malloc(oldsize+1))==NULL) ||
139 		(lseek(fd,0,SEEK_SET)!=0) ||
140 		(read(fd,old,oldsize)!=oldsize) ||
141 		(close(fd)==-1)) err(1,"%s",argv[1]);
142 	if((new=malloc(newsize+1))==NULL) err(1,NULL);
143 
144 	oldpos=0;newpos=0;
145 	while(newpos<newsize) {
146 		/* Read control data */
147 		for(i=0;i<=2;i++) {
148 			lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8);
149 			if ((lenread < 8) || ((cbz2err != BZ_OK) &&
150 			    (cbz2err != BZ_STREAM_END)))
151 				errx(1, "Corrupt patch\n");
152 			ctrl[i]=offtin(buf);
153 		};
154 
155 		// android local change (start)
156 		if (ctrl[0]<0||ctrl[1]<0)
157 			errx(1,"Corrupt patch\n");
158 		// android local change (end)
159 
160 		/* Sanity-check */
161 		if(newpos+ctrl[0]>newsize)
162 			errx(1,"Corrupt patch\n");
163 
164 		/* Read diff string */
165 		lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]);
166 		if ((lenread < ctrl[0]) ||
167 		    ((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
168 			errx(1, "Corrupt patch\n");
169 
170 		/* Add old data to diff string */
171 		for(i=0;i<ctrl[0];i++)
172 			if((oldpos+i>=0) && (oldpos+i<oldsize))
173 				new[newpos+i]+=old[oldpos+i];
174 
175 		/* Adjust pointers */
176 		newpos+=ctrl[0];
177 		oldpos+=ctrl[0];
178 
179 		/* Sanity-check */
180 		if(newpos+ctrl[1]>newsize)
181 			errx(1,"Corrupt patch\n");
182 
183 		/* Read extra string */
184 		lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]);
185 		if ((lenread < ctrl[1]) ||
186 		    ((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
187 			errx(1, "Corrupt patch\n");
188 
189 		/* Adjust pointers */
190 		newpos+=ctrl[1];
191 		oldpos+=ctrl[2];
192 	};
193 
194 	/* Clean up the bzip2 reads */
195 	BZ2_bzReadClose(&cbz2err, cpfbz2);
196 	BZ2_bzReadClose(&dbz2err, dpfbz2);
197 	BZ2_bzReadClose(&ebz2err, epfbz2);
198 	if (fclose(cpf) || fclose(dpf) || fclose(epf))
199 		err(1, "fclose(%s)", argv[3]);
200 
201 	/* Write the new file */
202 	if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
203 		(write(fd,new,newsize)!=newsize) || (close(fd)==-1))
204 		err(1,"%s",argv[2]);
205 
206 	free(new);
207 	free(old);
208 
209 	return 0;
210 }
211