81 lines
1.8 KiB
C
Executable File
81 lines
1.8 KiB
C
Executable File
#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/uio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <string.h>
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#include "tar.h"
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int main(int argc, char *argv[])
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{
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char *name = argv[1]; // name of archive
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int numberoffiles = argc - 3;
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char buffer[300]; // character buffer for write
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int fp, r, i, p;
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if (argc != 2)
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{
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fprintf(stderr, "%s: Usage: dah filename \n", strerror(5));
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exit(EXIT_FAILURE);
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}
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fp = open(name, O_RDONLY, 0644); // opens file; creates it if it does not exist;
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if (fp < 0)
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{
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fprintf(stderr, "cannot open %s because of %s\n", name, strerror(5));
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exit(EXIT_FAILURE);
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}
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write(1, "\n", 1);
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hdr header;
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while (true)
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{
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r = read(fp, &header, sizeof(hdr));
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if (r != sizeof(hdr))
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{
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fprintf(stderr, "%s: file is not the size of a header object\n", strerror(5));
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exit(EXIT_FAILURE);
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}
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else if (header.magic != 0x63746172)
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{
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fprintf(stderr, "%s: header does not include the magic number [magic number is: %x]\n", strerror(5), header.magic);
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exit(EXIT_FAILURE);
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}
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printf("magic number is: %x\n", header.magic);
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printf("The end of file pointer is at: %i\n", header.eop);
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printf("number of used blocks are: %i\n", header.block_count);
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for (i = 0; i < 8; i++)
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{
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printf("The filesize of block [%i] is %i\n", i, header.file_size[i]);
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}
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for (i = 0; i < 8; i++)
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{
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printf("Is block [%i] deleted? (1=true, 0=false): %i\n", i, header.deleted[i]);
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}
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for (i = 0; i < 8; i++)
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{
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printf("The filename in block [%i] is %i\n", i, header.file_name[i]);
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}
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printf("The next header is at: %i\n", header.next);
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if (header.next < 0)
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{
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printf("End of headers\n");
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exit(EXIT_SUCCESS);
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}
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else
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{
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p = header.next;
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lseek(fp, header.next, SEEK_SET);
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}
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}
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close(r);
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close(fp);
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return EXIT_SUCCESS;
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}
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