Pull fetching random bytes into the system-specific code.

[yaid] / yaid.c

diff --git a/yaid.c b/yaid.c
index cc3bb47..13e1208 100644 (file)
--- a/yaid.c
+++ b/yaid.c
@@ -61,6 +61,7 @@ struct client {
   struct listen *l;                    /* Back to the listener (and ops) */
   struct writebuf wb;                  /* Write buffer for our reply */
   struct proxy *px;                    /* Proxy if conn goes via NAT */
+  struct client *next;                 /* Next in a chain of clients */
 };
 
 /* A proxy connection. */
@@ -71,6 +72,7 @@ struct proxy {
   selbuf b;                            /* Accumulate the response line */
   struct writebuf wb;                  /* Write buffer for query */
   char nat[ADDRLEN];                   /* Server address, as text */
+  struct proxy *next;                  /* Next in a chain of proxies */
 };
 
 /*----- Static variables --------------------------------------------------*/
@@ -86,7 +88,9 @@ static fwatch polfw;                  /* Watch policy file for changes */
 
 static unsigned char tokenbuf[4096];   /* Random-ish data for tokens */
 static size_t tokenptr = sizeof(tokenbuf); /* Current read position */
-static int randfd;                     /* File descriptor for random data */
+
+static struct client *dead_clients = 0;        /* List of defunct clients */
+static struct proxy *dead_proxies = 0; /* List of defunct proxies */
 
 static unsigned flags = 0;             /* Various interesting flags */
 #define F_SYSLOG 1u                    /*   Use syslog for logging */
@@ -362,12 +366,28 @@ static void cancel_proxy(struct proxy *px)
     conn_kill(&px->cn);
   else {
     close(px->fd);
-    selbuf_destroy(&px->b);
-    free_writebuf(&px->wb);
+    selbuf_disable(&px->b);
   }
   px->c->px = 0;
   selbuf_enable(&px->c->b);
-  xfree(px);
+  px->next = dead_proxies;
+  dead_proxies = px;
+}
+
+/* Delayed destruction of unsafe parts of proxies. */
+static void reap_dead_proxies(void)
+{
+  struct proxy *px, *pp;
+
+  for (px = dead_proxies; px; px = pp) {
+    pp = px->next;
+    if (px->fd != -1) {
+      selbuf_destroy(&px->b);
+      free_writebuf(&px->wb);
+    }
+    xfree(px);
+  }
+  dead_proxies = 0;
 }
 
 /* Notification that a line (presumably a reply) has been received from the
@@ -543,12 +563,27 @@ err_0:
 /* Disconnect a client, freeing up any associated resources. */
 static void disconnect_client(struct client *c)
 {
+  selbuf_disable(&c->b);
   close(c->fd);
-  selbuf_destroy(&c->b);
   sel_rmtimer(&c->t);
   free_writebuf(&c->wb);
   if (c->px) cancel_proxy(c->px);
-  xfree(c);
+  c->next = dead_clients;
+  dead_clients = c;
+}
+
+/* Throw away dead clients now that we've reached a safe point in the
+ * program.
+ */
+static void reap_dead_clients(void)
+{
+  struct client *c, *cc;
+  for (c = dead_clients; c; c = cc) {
+    cc = c->next;
+    selbuf_destroy(&c->b);
+    xfree(c);
+  }
+  dead_clients = 0;
 }
 
 /* Time out a client because it's been idle for too long. */
@@ -590,8 +625,7 @@ static void user_token(char *p)
    * from the kernel.
    */
   if (tokenptr + TOKENRANDSZ >= sizeof(tokenbuf)) {
-    if (read(randfd, tokenbuf, sizeof(tokenbuf)) < sizeof(tokenbuf))
-      die(1, "unexpected short read or error from `/dev/urandom'");
+    fill_random(tokenbuf, sizeof(tokenbuf));
     tokenptr = 0;
   }
 
@@ -1056,12 +1090,6 @@ int main(int argc, char *argv[])
   if (load_policy_file(policyfile, &policy))
     exit(1);
 
-  /* Open the random data source. */
-  if ((randfd = open("/dev/urandom", O_RDONLY)) < 0) {
-    die(1, "failed to open `/dev/urandom' for reading: %s",
-       strerror(errno));
-  }
-
   /* Set up the I/O event system. */
   sel_init(&sel);
 
@@ -1108,6 +1136,8 @@ int main(int argc, char *argv[])
   for (;;) {
     if (sel_select(&sel) && errno != EINTR)
       die(1, "select failed: %s", strerror(errno));
+    reap_dead_proxies();
+    reap_dead_clients();
   }
 
   /* This just keeps the compiler happy. */