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42 lines
796 B
42 lines
796 B
#include <common.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <sys/stat.h>
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#define BSIZE 4096
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char buf[BSIZE];
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struct stat statbuf;
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int main(int argc, char *argv[])
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{
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if (argc != 2) {
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printf("Usage: %s filename\n", argv[0]);
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exit(-1);
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}
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if(stat(argv[1], &statbuf) < 0) {
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err(-1, "stat");
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}
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int fd = open(argv[1], O_RDONLY, 0);
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if (fd < 0)
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err(-1, "fopen");
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ulong cksum = 0;
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size_t tot = 0, r;
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while ((r = read(fd, buf, sizeof(buf))) > 0) {
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for (int i = 0; i < r; i++) {
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cksum += buf[i];
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}
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tot += r;
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}
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if (tot != statbuf.st_size) {
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printf("didn't read enough data\n");
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exit(-1);
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}
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printf("cksum: %s = cksum %lx tot %ld\n", argv[1], cksum, tot);
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return 0;
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}
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