217 lines
5.3 KiB
C
217 lines
5.3 KiB
C
/*
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.c -- Binary patcher
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Copyright 2003,2004 Colin Percival
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For the terms under which this work may be distributed, please see
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the adjoining file "LICENSE".
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*/
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#ifndef BZIP2
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#define BZIP2 "/usr/bin/bzip2"
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#endif
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#include <stdlib.h>
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#include <stdio.h>
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#include <err.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/wait.h>
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ssize_t loopread(int d,void *buf,size_t nbytes)
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{
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ssize_t ptr,lenread;
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for(ptr=0;ptr<nbytes;ptr+=lenread) {
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lenread=read(d,buf+ptr,nbytes-ptr);
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if(lenread==0) return ptr;
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if(lenread==-1) return -1;
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};
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return ptr;
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}
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int bz2read(int fd,off_t offset,off_t len,char * fname,pid_t * pids)
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{
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int p0[2],p1[2];
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u_char * data;
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if((pipe(p0)==-1) || (pipe(p1)==-1)) err(1,NULL);
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if((pids[0]=fork())==-1) err(1,NULL);
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if(pids[0]==0) {
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if(close(0) || close(1) || close(p0[0]) ||
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close(p1[0]) || close(p1[1])) err(1,NULL);
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if((data=malloc(len+1))==NULL) err(1,NULL);
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if((pread(fd,data,len,offset)!=len) || close(fd))
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err(1,"%s",fname);
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if((write(p0[1],data,len)!=len) || close(p0[1]))
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err(1,NULL);
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free(data);
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_exit(0);
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};
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if((pids[1]=fork())==-1) err(1,NULL);
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if(pids[1]==0) {
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if(close(0) || close(1) || close(p0[1]) ||
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close(p1[0])) err(1,NULL);
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if((dup2(p0[0],0)==-1) || close(p0[0])) err(1,NULL);
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if((dup2(p1[1],1)==-1) || close(p1[1])) err(1,NULL);
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if(close(fd)==-1) err(1,"%s",fname);
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execl(BZIP2,BZIP2,"-dc",NULL);
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err(1,"%s",BZIP2);
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};
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if(close(p0[0]) || close(p0[1]) || close(p1[1])) err(1,NULL);
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return p1[0];
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}
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off_t offtin(u_char *buf)
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{
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off_t y;
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y=buf[7]&0x7F;
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y=y*256;y+=buf[6];
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y=y*256;y+=buf[5];
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y=y*256;y+=buf[4];
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y=y*256;y+=buf[3];
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y=y*256;y+=buf[2];
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y=y*256;y+=buf[1];
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y=y*256;y+=buf[0];
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if(buf[7]&0x80) y=-y;
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return y;
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}
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int main(int argc,char * argv[])
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{
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int fd,ctrlpipe,diffpipe,extrapipe;
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pid_t pids[6];
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ssize_t patchsize,oldsize,newsize;
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ssize_t bzctrllen,bzdatalen;
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u_char header[32],buf[8];
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int version=0;
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u_char *old, *new;
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off_t oldpos,newpos;
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off_t ctrl[3];
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off_t lenread;
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off_t i;
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if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
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if(((fd=open(argv[3],O_RDONLY,0))<0) ||
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((patchsize=lseek(fd,0,SEEK_END))==-1) ||
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(lseek(fd,0,SEEK_SET)!=0)) err(1,"%s",argv[3]);
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if(patchsize<32) errx(1,"Corrupt patch\n");
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/*
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Ok, this is going to be messy. There are two different patch
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formats which we need to support.
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The old format (pre-4.0) is:
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0 8 "QSUFDIFF" or "BSDIFF30"
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8 8 X
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16 8 Y
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24 8 sizeof(newfile)
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32 X bzip2(control block)
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32+X Y bzip2(data block)
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with control block a set of pairs (x,y) meaning "seek forward
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in oldfile by y bytes, and add the next x bytes to x bytes from
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the data block".
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The new format (4.0) is:
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0 8 "BSDIFF40"
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8 8 X
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16 8 Y
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24 8 sizeof(newfile)
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32 X bzip2(control block)
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32+X Y bzip2(diff block)
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32+X+Y ??? bzip2(extra block)
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with control block a set of triples (x,y,z) meaning "add x bytes
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from oldfile to x bytes from the diff block; copy y bytes from the
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extra block; seek forwards in oldfile by z bytes".
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*/
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if(read(fd,header,32)!=32) err(1,"%s",argv[3]);
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if(memcmp(header,"QSUFDIFF",8)==0) version=1;
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if(memcmp(header,"BSDIFF30",8)==0) version=1;
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if(memcmp(header,"BSDIFF40",8)==0) version=2;
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if(!version) errx(1,"Corrupt patch\n");
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bzctrllen=offtin(header+8);
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bzdatalen=offtin(header+16);
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newsize=offtin(header+24);
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if((bzctrllen<0) || (bzdatalen<0) || (newsize<0) ||
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((version==1) && (32+bzctrllen+bzdatalen!=patchsize)))
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errx(1,"Corrupt patch\n");
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ctrlpipe=bz2read(fd,32,bzctrllen,argv[3],pids);
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diffpipe=bz2read(fd,32+bzctrllen,bzdatalen,argv[3],pids+2);
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if(version==2) {
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extrapipe=bz2read(fd,32+bzctrllen+bzdatalen,
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patchsize-(32+bzctrllen+bzdatalen),argv[3],pids+4);
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};
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if(close(fd)==-1) err(1,"%s",argv[3]);
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if(((fd=open(argv[1],O_RDONLY,0))<0) ||
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((oldsize=lseek(fd,0,SEEK_END))==-1) ||
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((old=malloc(oldsize+1))==NULL) ||
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(lseek(fd,0,SEEK_SET)!=0) ||
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(read(fd,old,oldsize)!=oldsize) ||
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(close(fd)==-1)) err(1,"%s",argv[1]);
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if((new=malloc(newsize+1))==NULL) err(1,NULL);
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oldpos=0;newpos=0;
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while(newpos<newsize) {
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for(i=0;i<=version;i++) {
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if((lenread=loopread(ctrlpipe,buf,8))<0) err(1,NULL);
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if(lenread<8) errx(1,"Corrupt patch\n");
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ctrl[i]=offtin(buf);
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};
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if(version==1) oldpos+=ctrl[1];
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if(newpos+ctrl[0]>newsize) errx(1,"Corrupt patch\n");
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if((lenread=loopread(diffpipe,new+newpos,ctrl[0]))<0)
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err(1,NULL);
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if(lenread!=ctrl[0]) errx(1,"Corrupt patch\n");
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for(i=0;i<ctrl[0];i++)
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if((oldpos+i>=0) && (oldpos+i<oldsize))
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new[newpos+i]+=old[oldpos+i];
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newpos+=ctrl[0];
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oldpos+=ctrl[0];
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if(version==2) {
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if(newpos+ctrl[1]>newsize) errx(1,"Corrupt patch\n");
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if((lenread=loopread(extrapipe,new+newpos,ctrl[1]))<0)
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err(1,NULL);
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if(lenread!=ctrl[1]) errx(1,"Corrupt patch\n");
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newpos+=ctrl[1];
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oldpos+=ctrl[2];
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};
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};
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if(loopread(ctrlpipe,buf,1)!=0) errx(1,"Corrupt patch\n");
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if(loopread(diffpipe,buf,1)!=0) errx(1,"Corrupt patch\n");
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if(version==2)
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if(loopread(extrapipe,buf,1)!=0) errx(1,"Corrupt patch\n");
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if(close(ctrlpipe) || close(diffpipe) ||
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((version==2) && close(extrapipe)))
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err(1,NULL);
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for(i=0;i<(version+1)*2;i++) waitpid(pids[i],NULL,0);
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if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
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(write(fd,new,newsize)!=newsize) || (close(fd)==-1))
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err(1,"%s",argv[2]);
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free(new);
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free(old);
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return 0;
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}
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