52 lines
878 B
C
52 lines
878 B
C
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#include <u.h>
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#include <libc.h>
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/*
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* After a fork with fd's copied, both fd's are pointing to
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* the same Chan structure. Since the offset is kept in the Chan
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* structure, the seek's and read's in the two processes can
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* compete at moving the offset around. Hence the unusual loop
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* in the middle of this routine.
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*/
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static long
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oldtime(long *tp)
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{
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char b[20];
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static int f = -1;
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int i, retries;
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long t;
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memset(b, 0, sizeof(b));
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for(retries = 0; retries < 100; retries++){
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if(f < 0)
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f = open("/dev/time", OREAD|OCEXEC);
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if(f < 0)
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break;
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if(seek(f, 0, 0) < 0 || (i = read(f, b, sizeof(b))) < 0){
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close(f);
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f = -1;
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} else {
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if(i != 0)
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break;
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}
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}
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t = atol(b);
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if(tp)
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*tp = t;
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return t;
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}
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long
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time(long *tp)
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{
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vlong t;
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t = nsec()/((vlong)1000000000);
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if(t == 0)
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t = oldtime(0);
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if(tp != nil)
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*tp = t;
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return t;
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}
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