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39 lines
784 B
C++
39 lines
784 B
C++
#include <time.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <Common/Exception.h>
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#include <Common/randomSeed.h>
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#include <Common/SipHash.h>
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#include <Core/Types.h>
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#ifdef __APPLE__
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#include <common/apple_rt.h>
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#endif
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int CANNOT_CLOCK_GETTIME;
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}
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}
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DB::UInt64 randomSeed()
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{
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struct timespec times;
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if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, ×))
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DB::throwFromErrno("Cannot clock_gettime.", DB::ErrorCodes::CANNOT_CLOCK_GETTIME);
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/// Not cryptographically secure as time, pid and stack address can be predictable.
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SipHash hash;
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hash.update(times.tv_nsec);
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hash.update(times.tv_sec);
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hash.update(getpid());
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hash.update(×);
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return hash.get64();
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}
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