Clean up and modernize librandom.

 Correct random number generation has historically been
suprisingly painful to achieve. There was no standard,
every system behaved in a subtly different way, and there
were a few userland initiatives to get decent randomness,
all incompatible of course.
 The situation is a bit better now, we're heading towards
some standardization. The arc4random() series of functions
is a good API, and available on a lot of systems -
unfortunately not Linux, but on Linux the new getrandom()
makes using /dev/random obsolete.

 So I removed the old crap in librandom, dropped EGD support,
dropped dynamic backend selection, made a single API series
(random_* instead of goodrandom_* and badrandom_*), added
an arc4random backend and a getrandom backend, and defaulted
to /dev/urandom backed up by SURF in the worst case. This
should be much smaller and logical. However, it's a major
API break, so the skarnet.org stack will be changed to
adapt.

1 files changed, 75 insertions, 0 deletions

diff --git a/src/librandom/random_init.c b/src/librandom/random_init.c
new file mode 100644
index 0000000..e990fb4
--- /dev/null
+++ b/src/librandom/random_init.c
@@ -0,0 +1,75 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+
+#ifdef SKALIBS_HASARC4RANDOM
+
+#include <stdlib.h>
+#include <skalibs/random.h>
+
+int random_init ()
+{
+  char seed[160] ;
+  random_makeseed(seed) ;
+  arc4random_addrandom(seed, 160) ;
+  return 1 ;
+}
+
+#else
+#ifdef SKALIBS_HASGETRANDOM
+
+#include <skalibs/djbunix.h>
+#include <skalibs/random.h>
+
+int random_init ()
+{
+  char seed[160] ;
+  random_makeseed(seed) ;
+  return openwritenclose_unsafe("/dev/urandom", seed, 160) ;
+}
+
+#else
+#ifdef SKALIBS_HASDEVURANDOM
+
+#include <skalibs/djbunix.h>
+#include <skalibs/random.h>
+#include "random-internal.h"
+
+int random_fd = -1 ;
+SURFSchedule surf_here = SURFSCHEDULE_ZERO ;
+
+int random_init ()
+{
+  int fd ;
+  char seed[160] ;
+  random_makeseed(seed) ;
+  surf_init(&surf_here, seed) ;
+  if (!openwritenclose_unsafe("/dev/urandom", seed, 160)) return 0 ;
+  if (random_fd < 0)
+  {
+    fd = open_readb("/dev/urandom") ;
+    if (fd < 0) return 0 ;
+    if (coe(fd) < 0) { fd_close(fd) ; return 0 ; }
+    random_fd = fd ;
+  }
+  return 1 ;
+}
+
+#else /* default */
+
+#include <skalibs/random.h>
+#include "random-internal.h"
+
+SURFSchedule surf_here = SURFSCHEDULE_ZERO ;
+
+int random_init ()
+{
+  char seed[160] ;
+  random_makeseed(seed) ;
+  surf_init(&surf_here, seed) ;
+  return 1 ;
+}
+
+#endif
+#endif
+#endif