From 0e5b2871ca6456b01d4bf037a6e68badf1ff1a41 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henryk=20Pl=C3=B6tz?= <henryk@ploetzli.ch>
Date: Fri, 3 Oct 2014 19:58:52 +0200
Subject: Initial commit of djbdns-1.05.tar.gz Source was
 http://cr.yp.to/djbdns/djbdns-1.05.tar.gz, SHA1
 2efdb3a039d0c548f40936aa9cb30829e0ce8c3d

---
 dns_rcrw.c | 131 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 dns_rcrw.c

(limited to 'dns_rcrw.c')

diff --git a/dns_rcrw.c b/dns_rcrw.c
new file mode 100644
index 0000000..a43f39f
--- /dev/null
+++ b/dns_rcrw.c
@@ -0,0 +1,131 @@
+#include <unistd.h>
+#include "taia.h"
+#include "env.h"
+#include "byte.h"
+#include "str.h"
+#include "openreadclose.h"
+#include "dns.h"
+
+static stralloc data = {0};
+
+static int init(stralloc *rules)
+{
+  char host[256];
+  const char *x;
+  int i;
+  int j;
+  int k;
+
+  if (!stralloc_copys(rules,"")) return -1;
+
+  x = env_get("DNSREWRITEFILE");
+  if (!x) x = "/etc/dnsrewrite";
+
+  i = openreadclose(x,&data,64);
+  if (i == -1) return -1;
+
+  if (i) {
+    if (!stralloc_append(&data,"\n")) return -1;
+    i = 0;
+    for (j = 0;j < data.len;++j)
+      if (data.s[j] == '\n') {
+        if (!stralloc_catb(rules,data.s + i,j - i)) return -1;
+        while (rules->len) {
+          if (rules->s[rules->len - 1] != ' ')
+          if (rules->s[rules->len - 1] != '\t')
+          if (rules->s[rules->len - 1] != '\r')
+            break;
+          --rules->len;
+        }
+        if (!stralloc_0(rules)) return -1;
+        i = j + 1;
+      }
+    return 0;
+  }
+
+  x = env_get("LOCALDOMAIN");
+  if (x) {
+    if (!stralloc_copys(&data,x)) return -1;
+    if (!stralloc_append(&data," ")) return -1;
+    if (!stralloc_copys(rules,"?:")) return -1;
+    i = 0;
+    for (j = 0;j < data.len;++j)
+      if (data.s[j] == ' ') {
+        if (!stralloc_cats(rules,"+.")) return -1;
+        if (!stralloc_catb(rules,data.s + i,j - i)) return -1;
+        i = j + 1;
+      }
+    if (!stralloc_0(rules)) return -1;
+    if (!stralloc_cats(rules,"*.:")) return -1;
+    if (!stralloc_0(rules)) return -1;
+    return 0;
+  }
+
+  i = openreadclose("/etc/resolv.conf",&data,64);
+  if (i == -1) return -1;
+
+  if (i) {
+    if (!stralloc_append(&data,"\n")) return -1;
+    i = 0;
+    for (j = 0;j < data.len;++j)
+      if (data.s[j] == '\n') {
+        if (byte_equal("search ",7,data.s + i) || byte_equal("search\t",7,data.s + i) || byte_equal("domain ",7,data.s + i) || byte_equal("domain\t",7,data.s + i)) {
+          if (!stralloc_copys(rules,"?:")) return -1;
+          i += 7;
+          while (i < j) {
+            k = byte_chr(data.s + i,j - i,' ');
+            k = byte_chr(data.s + i,k,'\t');
+            if (!k) { ++i; continue; }
+            if (!stralloc_cats(rules,"+.")) return -1;
+            if (!stralloc_catb(rules,data.s + i,k)) return -1;
+            i += k;
+          }
+          if (!stralloc_0(rules)) return -1;
+          if (!stralloc_cats(rules,"*.:")) return -1;
+          if (!stralloc_0(rules)) return -1;
+          return 0;
+        }
+        i = j + 1;
+      }
+  }
+
+  host[0] = 0;
+  if (gethostname(host,sizeof host) == -1) return -1;
+  host[(sizeof host) - 1] = 0;
+  i = str_chr(host,'.');
+  if (host[i]) {
+    if (!stralloc_copys(rules,"?:")) return -1;
+    if (!stralloc_cats(rules,host + i)) return -1;
+    if (!stralloc_0(rules)) return -1;
+  }
+  if (!stralloc_cats(rules,"*.:")) return -1;
+  if (!stralloc_0(rules)) return -1;
+
+  return 0;
+}
+
+static int ok = 0;
+static unsigned int uses;
+static struct taia deadline;
+static stralloc rules = {0}; /* defined if ok */
+
+int dns_resolvconfrewrite(stralloc *out)
+{
+  struct taia now;
+
+  taia_now(&now);
+  if (taia_less(&deadline,&now)) ok = 0;
+  if (!uses) ok = 0;
+
+  if (!ok) {
+    if (init(&rules) == -1) return -1;
+    taia_uint(&deadline,600);
+    taia_add(&deadline,&now,&deadline);
+    uses = 10000;
+    ok = 1;
+  }
+
+  --uses;
+  if (!stralloc_copy(out,&rules)) return -1;
+  return 0;
+}
-- 
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