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author | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-18 18:55:44 +0000 |
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committer | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-18 18:55:44 +0000 |
commit | 3534b428629be185e096be99e3bd5fdfe32d5544 (patch) | |
tree | 210ef3198ed66bc7f7b7bf6a85e4579f455e5a36 /src/sysdeps/trydevrandom.c | |
download | skalibs-3534b428629be185e096be99e3bd5fdfe32d5544.tar.xz |
initial commit with rc for skalibs-2.0.0.0
Diffstat (limited to 'src/sysdeps/trydevrandom.c')
-rw-r--r-- | src/sysdeps/trydevrandom.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/src/sysdeps/trydevrandom.c b/src/sysdeps/trydevrandom.c new file mode 100644 index 0000000..395d008 --- /dev/null +++ b/src/sysdeps/trydevrandom.c @@ -0,0 +1,54 @@ +/* ISC license. */ + +#include <unistd.h> +#include <sys/types.h> +#include <fcntl.h> +#include <errno.h> + +static int fd_read (int fd, char *buf, unsigned int len) +{ + register int r ; + do r = read(fd, buf, len) ; + while ((r == -1) && (errno == EINTR)) ; + return r ; +} + +static unsigned int allread (int fd, register char *buf, register unsigned int len) +{ + register unsigned int written = 0 ; + while (len) + { + register int w = fd_read(fd, buf, len) ; + if (!w) errno = EPIPE ; + if (w <= 0) break ; + written += w ; + buf += w ; + len -= w ; + } + return written ; +} + +static int byte_diff (char *s, unsigned int n, char *t) +{ + for (;;) + { + if (!n) return 0 ; + if (*s != *t) break ; + ++s ; ++t ; --n ; + } + return ((int)(unsigned int)(unsigned char) *s) + - ((int)(unsigned int)(unsigned char) *t); +} + +int main () +{ + char a[64] ; + char b[64] ; + int fd = open("/dev/random", O_RDONLY) ; + if ((fd == -1) || (allread(fd, a, 64) < 64) ) return 111 ; + close(fd) ; + fd = open("/dev/random", O_RDONLY) ; + if ((fd == -1) || (allread(fd, b, 64) < 64) ) return 111 ; + close(fd) ; + return !byte_diff(a, 64, b) ; +} |