37 lines
752 B
C
37 lines
752 B
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#define SZBUF 256
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int main(int argc, char const *argv[]){
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int fd,n,l,x;
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long int i, offset;
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if (argc<3){
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fprintf(stderr,"Usage : %s <file_name> <offset> \r",argv[0]);
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exit (1);
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} fd=open (argv[1], O_RDONLY);
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if (fd==-1){
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perror("Opening destination file fails");
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exit (2);
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} i=strtol(argv[2],NULL,0);
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offset=i*(sizeof(int));
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l=lseek(fd,offset,SEEK_SET);
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if(l==1){
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perror("lsink failed");
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close(fd);
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exit (3);
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}
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n=read(fd,&x,sizeof(int));
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if(n==-1){
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perror("Read in file failed");
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close(fd);
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exit (4);
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} if(n==0){
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printf("Out of range\n");
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} else{
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printf("The number at offset %ld is 0x%08x --> %d \n",i,x,x);
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} close(fd);
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exit(0);
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}
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