From 6b837b229fd02977d885a05c6fbb81cb2e0313f4 Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Sat, 13 Jul 2013 16:34:40 +0100
Subject: [PATCH] rand/noise.c (noise_filter): Use the <mLib/sel.h> machinery.

Makes things a little more verbose but rather simpler.
---
 rand/noise.c | 75 ++++++++++++++++++++++++++++++++----------------------------
 1 file changed, 40 insertions(+), 35 deletions(-)

diff --git a/rand/noise.c b/rand/noise.c
index fb4c4531..3bece706 100644
--- a/rand/noise.c
+++ b/rand/noise.c
@@ -48,6 +48,7 @@
 
 #include <mLib/bits.h>
 #include <mLib/mdup.h>
+#include <mLib/sel.h>
 #include <mLib/tv.h>
 
 #include "noise.h"
@@ -228,13 +229,43 @@ 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 +329,13 @@ 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 +345,11 @@ 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@ --- *
-- 
2.11.0