After some complaints about the dir names, the random device is

now in dirs called sys/*/random/ instead of sys/*/randomdev/*.

Introduce blocking, but only at startup; the random device will
block until the first reseed happens to prevent clients from
using untrustworthy output.

Provide a read_random() call for the rest of the kernel so that
the entropy device does not need to be present. This means that
things like IPX no longer need to have "device random" hardcoded
into thir kernel config. The downside is that read_random() will
provide very poor output until the entropy device is loaded and
reseeded. It is recommended that developers do NOT use the
read_random() call; instead, they should use arc4random() which
internally uses read_random().

Clean up the mutex and locking code a bit; this makes it possible
to unload the module again.

1 files changed, 37 insertions, 9 deletions

diff --git a/sys/dev/random/randomdev.c b/sys/dev/random/randomdev.c
index d6796ef..eaa47b9 100644
--- a/sys/dev/random/randomdev.c
+++ b/sys/dev/random/randomdev.c
@@ -36,20 +36,24 @@
 #include <sys/malloc.h>
 #include <sys/module.h>
 #include <sys/bus.h>
+#include <sys/poll.h>
 #include <sys/proc.h>
+#include <sys/select.h>
 #include <sys/random.h>
+#include <sys/vnode.h>
 #include <machine/bus.h>
 #include <machine/resource.h>
 #include <sys/sysctl.h>
 #include <crypto/blowfish/blowfish.h>
 
-#include <dev/randomdev/hash.h>
-#include <dev/randomdev/yarrow.h>
+#include <dev/random/hash.h>
+#include <dev/random/yarrow.h>
 
 static d_open_t random_open;
 static d_read_t random_read;
 static d_write_t random_write;
 static d_ioctl_t random_ioctl;
+static d_poll_t random_poll;
 
 #define CDEV_MAJOR	2
 #define RANDOM_MINOR	3
@@ -61,7 +65,7 @@ static struct cdevsw random_cdevsw = {
 	/* read */	random_read,
 	/* write */	random_write,
 	/* ioctl */	random_ioctl,
-	/* poll */	nopoll,
+	/* poll */	random_poll,
 	/* mmap */	nommap,
 	/* strategy */	nostrategy,
 	/* name */	"random",
@@ -105,13 +109,22 @@ random_read(dev_t dev, struct uio *uio, int flag)
 	int error = 0;
 	void *random_buf;
 
-	c = min(uio->uio_resid, PAGE_SIZE);
-	random_buf = (void *)malloc(c, M_TEMP, M_WAITOK);
-	while (uio->uio_resid > 0 && error == 0) {
-		ret = read_random(random_buf, c);
-		error = uiomove(random_buf, ret, uio);
+	if (flag & IO_NDELAY && !random_state.seeded) {
+		error =  EWOULDBLOCK;
+	}
+	else {
+		if (random_state.seeded) {
+			c = min(uio->uio_resid, PAGE_SIZE);
+			random_buf = (void *)malloc(c, M_TEMP, M_WAITOK);
+			while (uio->uio_resid > 0 && error == 0) {
+				ret = read_random_real(random_buf, c);
+				error = uiomove(random_buf, ret, uio);
+			}
+			free(random_buf, M_TEMP);
+		}
+		else
+			error = tsleep(&random_state, 0, "rndblk", 0);
 	}
-	free(random_buf, M_TEMP);
 	return error;
 }
 
@@ -141,6 +154,21 @@ random_ioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p)
 }
 
 static int
+random_poll(dev_t dev, int events, struct proc *p)
+{
+	int revents;
+
+	revents = 0;
+	if (events & (POLLIN | POLLRDNORM)) {
+		if (random_state.seeded)
+			revents = events & (POLLIN | POLLRDNORM);
+		else
+			selrecord(p, &random_state.rsel);
+	}
+	return revents;
+}
+
+static int
 random_modevent(module_t mod, int type, void *data)
 {
 	int error;