$NetBSD: patch-bitstir_c,v 1.2 2012/09/16 04:33:43 dholland Exp $

Get gMaxEntropy and gCriticalEntropyThreshold from the kernel in the
approved way, including at tls@'s suggestion a fallback in case the
reported threshold is 0.

Also, fix a couple C usage issues.

--- bitstir.c~	2003-08-27 16:58:51.000000000 -0400
+++ bitstir.c	2012-09-16 00:27:33.000000000 -0400
@@ -40,11 +40,13 @@
 #include <sys/wait.h>
 #include <syslog.h>
 #include <unistd.h>
+#include <paths.h>
+#include <sha1.h>
 
 const char gRequiredOS[] = "NetBSD";
-const char gRandomDevice[] = "/dev/random";
+const char gRandomDevice[] = _PATH_RANDOM;
-const long gMaxEntropy = RND_POOLBITS;
-const long gCriticalEntropyThreshold = RND_POOLBITS / 10;
+long gMaxEntropy;
+long gCriticalEntropyThreshold;
 const long gMaxPathLen = PATH_MAX;
 
 long verbose_flag = 0;
@@ -76,8 +77,8 @@
 
 void parse_command_line_args (int argc, char *argv[]);
 long entropy_available(const char *device);
-void restore_entropy();
-void restore_entropy_one_shot();
+void restore_entropy(void);
+void restore_entropy_one_shot(void);
 void nullify_fd (int fd);
 void exec_find (const char *directory);
 void kill_process (pid_t pid);
@@ -88,9 +89,10 @@
 void check_os ();
 int is_directory (const char *path);
 void setup_find_executable ();
+void get_random_stats(void);
 void print_help ();
 
-main(int argc, char *argv[])
+int main(int argc, char *argv[])
 {
   if( argc == 1 ) {
     fprintf(stderr, "usage: %s [switches] --search-dir dir [--search-dir dir ...]\n",
@@ -120,6 +122,7 @@
     check_os();
   }
   setup_find_executable();
+  get_random_stats();
 
   if( root_search_dir == (struct search_dir *) NULL ) {
     log_err("No directory specified with --search-dir.  Exiting.\n");
@@ -578,6 +582,31 @@
   }
 }
 
+void get_random_stats(void)
+{
+  rndpoolstat_t rs;
+  int fd;
+
+  fd = open(_PATH_URANDOM, O_RDONLY, 0644);
+  if (fd < 0) {
+    log_err("Could not open %s: %s\n", _PATH_URANDOM, strerror(errno));
+    exit(1);
+  }
+
+  if (ioctl(fd, RNDGETPOOLSTAT, &rs) < 0) {
+    log_err("RNDGETPOOLSTAT failed: %s\n", strerror(errno));
+    exit(1);
+  }
+
+  close(fd);
+
+  gMaxEntropy = rs.maxentropy;
+  gCriticalEntropyThreshold = rs.threshold;
+  if (gCriticalEntropyThreshold < 2 * SHA1_DIGEST_LENGTH) {
+    gCriticalEntropyThreshold = 2 * SHA1_DIGEST_LENGTH;
+  }
+}
+
 void print_help()
 {
     fprintf(stderr, "Basic help message - see bitstir(8) for more detail:\n");