diff options
Diffstat (limited to 'unix.c')
| -rw-r--r-- | unix.c | 65 |
1 files changed, 0 insertions, 65 deletions
@@ -225,69 +225,4 @@ double gettime() return( (double) time->tv_sec + (double) time->tv_usec / 1000000 ); } -/* A pretty reliable random number generator. Tries to use the /dev/random - devices first, and falls back to the random number generator from libc - when it fails. Opens randomizer devices with O_NONBLOCK to make sure a - lack of entropy won't halt BitlBee. */ -void random_bytes( unsigned char *buf, int count ) -{ - static int use_dev = -1; - - /* Actually this probing code isn't really necessary, is it? */ - if( use_dev == -1 ) - { - if( access( "/dev/random", R_OK ) == 0 || access( "/dev/urandom", R_OK ) == 0 ) - use_dev = 1; - else - { - use_dev = 0; - srand( ( getpid() << 16 ) ^ time( NULL ) ); - } - } - - if( use_dev ) - { - int fd; - - /* At least on Linux, /dev/random can block if there's not - enough entropy. We really don't want that, so if it can't - give anything, use /dev/urandom instead. */ - if( ( fd = open( "/dev/random", O_RDONLY | O_NONBLOCK ) ) >= 0 ) - if( read( fd, buf, count ) == count ) - { - close( fd ); - return; - } - close( fd ); - - /* urandom isn't supposed to block at all, but just to be - sure. If it blocks, we'll disable use_dev and use the libc - randomizer instead. */ - if( ( fd = open( "/dev/urandom", O_RDONLY | O_NONBLOCK ) ) >= 0 ) - if( read( fd, buf, count ) == count ) - { - close( fd ); - return; - } - close( fd ); - - /* If /dev/random blocks once, we'll still try to use it - again next time. If /dev/urandom also fails for some - reason, stick with libc during this session. */ - - use_dev = 0; - srand( ( getpid() << 16 ) ^ time( NULL ) ); - } - - if( !use_dev ) - { - int i; - - /* Possibly the LSB of rand() isn't very random on some - platforms. Seems okay on at least Linux and OSX though. */ - for( i = 0; i < count; i ++ ) - buf[i] = rand() & 0xff; - } -} - |