Date: Tue, 9 Oct 2012 14:25:15 +0000 (UTC) From: Eitan Adler <eadler@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r241373 - head/lib/libc/stdlib Message-ID: <201210091425.q99EPFS6020787@svn.freebsd.org>
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Author: eadler Date: Tue Oct 9 14:25:14 2012 New Revision: 241373 URL: http://svn.freebsd.org/changeset/base/241373 Log: Remove undefined behavior from sranddev() and srandomdev(). This doesn't actually work with any modern C compiler: In particular, both clang and modern gcc verisons silently elide any xor operation with 'junk'. Approved by: secteam MFC after: 3 days Modified: head/lib/libc/stdlib/rand.c head/lib/libc/stdlib/random.c Modified: head/lib/libc/stdlib/rand.c ============================================================================== --- head/lib/libc/stdlib/rand.c Tue Oct 9 13:21:08 2012 (r241372) +++ head/lib/libc/stdlib/rand.c Tue Oct 9 14:25:14 2012 (r241373) @@ -130,10 +130,9 @@ sranddev() if (!done) { struct timeval tv; - unsigned long junk; gettimeofday(&tv, NULL); - srand((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec ^ junk); + srand((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec); } } Modified: head/lib/libc/stdlib/random.c ============================================================================== --- head/lib/libc/stdlib/random.c Tue Oct 9 13:21:08 2012 (r241372) +++ head/lib/libc/stdlib/random.c Tue Oct 9 14:25:14 2012 (r241373) @@ -312,10 +312,9 @@ srandomdev(void) if (!done) { struct timeval tv; - volatile unsigned long junk; gettimeofday(&tv, NULL); - srandom((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec ^ junk); + srandom((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec); return; }
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