X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/cbc993efd7c38bb71bb179feed22d440474f4f36..6d4416ccb0bbe02105c4b9dfa1442b9198c0d923:/rand/noise.c

diff --git a/rand/noise.c b/rand/noise.c
index fb4c4531..2c30c13c 100644
--- a/rand/noise.c
+++ b/rand/noise.c
@@ -29,6 +29,7 @@
 
 #include "config.h"
 
+#include <errno.h>
 #include <setjmp.h>
 #include <signal.h>
 #include <stdio.h>
@@ -46,8 +47,14 @@
 #  include <grp.h>
 #endif
 
+#if defined(HAVE_LINUX_RANDOM_H)
+#  include <linux/random.h>
+#  include <sys/syscall.h>
+#endif
+
 #include <mLib/bits.h>
 #include <mLib/mdup.h>
+#include <mLib/sel.h>
 #include <mLib/tv.h>
 
 #include "noise.h"
@@ -86,8 +93,8 @@ static gid_t noise_gid = NOISE_NOSETGID; /* Gid to set to spawn processes */
 
 static int bitcount(unsigned long x)
 {
-  char ctab[] = { 0, 1, 1, 2, 1, 2, 2, 3,
-		  1, 2, 2, 3, 2, 3, 3, 4 };
+  static const char ctab[] = { 0, 1, 1, 2, 1, 2, 2, 3,
+			       1, 2, 2, 3, 2, 3, 3, 4 };
   int count = 0;
   while (x) {
     count += ctab[x & 0xfu];
@@ -156,11 +163,57 @@ int noise_timer(rand_pool *r)
 
 int noise_devrandom(rand_pool *r)
 {
-  int fd;
+  int fd = -1;
   octet buf[RAND_POOLSZ];
   ssize_t len;
   size_t n = 0;
   int ret = 0;
+#ifdef __linux__
+  fd_set infd;
+  struct timeval tv = { 0, 0 };
+#endif
+#ifdef HAVE_GETENTROPY
+  size_t nn;
+#endif
+
+#if defined(HAVE_LINUX_RANDOM_H) &&					\
+    defined(GRND_NONBLOCK) &&						\
+    defined(SYS_getrandom)
+  /* --- Use the new shinies if available --- */
+
+  while (n < sizeof(buf)) {
+    if ((len = syscall(SYS_getrandom, buf + n, sizeof(buf) - n,
+		       GRND_NONBLOCK)) <= 0) {
+      if (errno == ENOSYS) break;
+      else goto done;
+    }
+    n += len;
+  }
+  if (n == sizeof(buf)) goto win;
+#endif
+
+#ifdef HAVE_GETENTROPY
+  /* --- OpenBSD-flavoured shinies --- */
+
+  while (n < sizeof(buf)) {
+    nn = sizeof(buf) - nn;
+    if (nn > 256) nn = 256;
+    if (getentropy(buf + n, nn)) break;
+    n += nn;
+  }
+  if (n == sizeof(buf)) goto win;
+#endif
+
+#ifdef __linux__
+  /* --- Don't take from `/dev/urandom' if `/dev/random' would block --- */
+
+  if ((fd = open("/dev/random", O_RDONLY | O_NONBLOCK)) < 0) goto done;
+  FD_ZERO(&infd);
+  FD_SET(fd, &infd);
+  if (select(fd + 1, &infd, 0, 0, &tv) < 0 || !FD_ISSET(fd, &infd))
+    goto done;
+  close(fd); fd = -1;
+#endif
 
   /* --- Be nice to other clients of the random device --- *
    *
@@ -170,18 +223,24 @@ int noise_devrandom(rand_pool *r)
    * needs to get some more entropy from somewhere.
    */
 
-  if ((fd = open("/dev/urandom", O_RDONLY | O_NONBLOCK)) >= 0 ||
+  if (fd >= 0 ||
+      (fd = open("/dev/urandom", O_RDONLY | O_NONBLOCK)) >= 0 ||
       (fd = open("/dev/arandom", O_RDONLY | O_NONBLOCK)) >= 0 ||
       (fd = open("/dev/random", O_RDONLY | O_NONBLOCK)) >= 0) {
     while (n < sizeof(buf)) {
       if ((len = read(fd, buf + n, sizeof(buf) - n)) <= 0) break;
       n += len;
     }
-    rand_add(r, buf, n, n * 8);
-    BURN(buf);
-    if (n == sizeof(buf)) ret = 1;
-    close(fd);
+    if (n == sizeof(buf)) goto win;
   }
+  goto done;
+
+win:
+  ret = 1;
+done:
+  if (fd >= 0) close(fd);
+  rand_add(r, buf, n, 8*n);
+  BURN(buf);
   noise_timer(r);
   return (ret);
 }
@@ -228,13 +287,43 @@ void noise_setid(uid_t uid, gid_t gid)
  *		This interface is Unix-specific.
  */
 
+struct noisekid {
+  rand_pool *r;
+  int good;
+  char buf[4096];
+  int donep;
+  int ret;
+};
+
+static void kid_read(int fd, unsigned mode, void *p)
+{
+  struct noisekid *nk = p;
+  ssize_t sz;
+  int goodbits;
+
+  noise_timer(nk->r);
+  if ((sz = read(fd, nk->buf, sizeof(nk->buf))) <= 0)
+    nk->donep = 1;
+  else {
+    goodbits = (sz * nk->good) / 128;
+    rand_add(nk->r, nk->buf, sz, goodbits);
+    nk->ret = 1;
+  }
+}
+
+static void kid_dead(struct timeval *tv, void *p)
+  { struct noisekid *nk = p; nk->donep = 1; }
+
 int noise_filter(rand_pool *r, int good, const char *c)
 {
-  char buf[4096];
   pid_t kid;
   int fd[2];
   struct timeval dead;
   int ret = 0;
+  struct noisekid nk = { 0 };
+  sel_state sel;
+  sel_file sf;
+  sel_timer st;
   const char *env[] = {
     "PATH=/bin:/usr/bin:/sbin:/usr/sbin:/etc",
     0
@@ -298,39 +387,13 @@ int noise_filter(rand_pool *r, int good, const char *c)
   /* --- Sort out my end of the deal --- */
 
   close(fd[1]);
-
-  /* --- Decide on the deadline --- */
-
+  sel_init(&sel);
+  nk.r = r; nk.good = good;
   TV_ADDL(&dead, &dead, 0, NOISE_KIDLIFE);
-
-  /* --- Now read, and think --- */
-
-  for (;;) {
-    struct timeval now, diff;
-    fd_set rd;
-
-    gettimeofday(&now, 0);
-    timer(r, &now);
-    if (TV_CMP(&now, >, &dead))
-      break;
-    TV_SUB(&diff, &dead, &now);
-
-    FD_ZERO(&rd);
-    FD_SET(fd[0], &rd);
-
-    if (select(fd[0] + 1, &rd, 0, 0, &diff) < 0)
-      break;
-    if (FD_ISSET(fd[0], &rd)) {
-      ssize_t sz;
-      int goodbits;
-
-      if ((sz = read(fd[0], buf, sizeof(buf))) <= 0)
-	break;
-      goodbits = (sz * good) / 128;
-      rand_add(r, buf, sz, goodbits);
-      ret = 1;
-    }
-  }
+  sel_initfile(&sel, &sf, fd[0], SEL_READ, kid_read, &nk);
+  sel_addfile(&sf);
+  sel_addtimer(&sel, &st, &dead, kid_dead, &nk);
+  while (!nk.donep && !sel_select(&sel));
 
   /* --- We've finished with it: kill the child process --- *
    *
@@ -340,11 +403,11 @@ int noise_filter(rand_pool *r, int good, const char *c)
    */
 
   close(fd[0]);
-  BURN(buf);
+  BURN(nk.buf);
   noise_timer(r);
   kill(kid, SIGKILL);
   waitpid(kid, 0, 0);
-  return (ret);
+  return (nk.ret);
 }
 
 /* --- @noise_freewheel@ --- *
@@ -360,7 +423,7 @@ int noise_filter(rand_pool *r, int good, const char *c)
 
 #ifdef USE_FREEWHEEL
 
-static jmp_buf fwjmp;
+static sigjmp_buf fwjmp;
 
 static void fwalarm(int sig)
 {