ares 1.1.1 with collected applied patches

1 files changed, 273 insertions, 0 deletions

diff --git a/ares_search.c b/ares_search.c
new file mode 100644
index 0000000..4108065
--- /dev/null
+++ b/ares_search.c
@@ -0,0 +1,273 @@
+/* Copyright 1998 by the Massachusetts Institute of Technology.
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software and its documentation for any purpose and without
+ * fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting
+ * documentation, and that the name of M.I.T. not be used in
+ * advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is"
+ * without express or implied warranty.
+ */
+
+static const char rcsid[] = "$Id$";
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+#ifdef WIN32
+#include "nameser.h"
+#endif
+
+#include "ares.h"
+#include "ares_private.h"
+
+struct search_query {
+  /* Arguments passed to ares_search */
+  ares_channel channel;
+  char *name;			/* copied into an allocated buffer */
+  int dnsclass;
+  int type;
+  ares_callback callback;
+  void *arg;
+
+  int status_as_is;		/* error status from trying as-is */
+  int next_domain;		/* next search domain to try */
+  int trying_as_is;		/* current query is for name as-is */
+};
+
+static void search_callback(void *arg, int status, unsigned char *abuf,
+			    int alen);
+static void end_squery(struct search_query *squery, int status,
+		       unsigned char *abuf, int alen);
+static int cat_domain(const char *name, const char *domain, char **s);
+static int single_domain(ares_channel channel, const char *name, char **s);
+
+void ares_search(ares_channel channel, const char *name, int dnsclass,
+		 int type, ares_callback callback, void *arg)
+{
+  struct search_query *squery;
+  char *s;
+  const char *p;
+  int status, ndots;
+
+  /* If name only yields one domain to search, then we don't have
+   * to keep extra state, so just do an ares_query().
+   */
+  status = single_domain(channel, name, &s);
+  if (status != ARES_SUCCESS)
+    {
+      callback(arg, status, NULL, 0);
+      return;
+    }
+  if (s)
+    {
+      ares_query(channel, s, dnsclass, type, callback, arg);
+      free(s);
+      return;
+    }
+
+  /* Allocate a search_query structure to hold the state necessary for
+   * doing multiple lookups.
+   */
+  squery = malloc(sizeof(struct search_query));
+  if (!squery)
+    {
+      callback(arg, ARES_ENOMEM, NULL, 0);
+      return;
+    }
+  squery->channel = channel;
+  squery->name = strdup(name);
+  if (!squery->name)
+    {
+      free(squery);
+      callback(arg, ARES_ENOMEM, NULL, 0);
+      return;
+    }
+  squery->dnsclass = dnsclass;
+  squery->type = type;
+  squery->status_as_is = -1;
+  squery->callback = callback;
+  squery->arg = arg;
+
+  /* Count the number of dots in name. */
+  ndots = 0;
+  for (p = name; *p; p++)
+    {
+      if (*p == '.')
+	ndots++;
+    }
+
+  /* If ndots is at least the channel ndots threshold (usually 1),
+   * then we try the name as-is first.  Otherwise, we try the name
+   * as-is last.
+   */
+  if (ndots >= channel->ndots)
+    {
+      /* Try the name as-is first. */
+      squery->next_domain = 0;
+      squery->trying_as_is = 1;
+      ares_query(channel, name, dnsclass, type, search_callback, squery);
+    }
+  else
+    {
+      /* Try the name as-is last; start with the first search domain. */
+      squery->next_domain = 1;
+      squery->trying_as_is = 0;
+      status = cat_domain(name, channel->domains[0], &s);
+      if (status == ARES_SUCCESS)
+	{
+	  ares_query(channel, s, dnsclass, type, search_callback, squery);
+	  free(s);
+	}
+      else
+	callback(arg, status, NULL, 0);
+    }
+}
+
+static void search_callback(void *arg, int status, unsigned char *abuf,
+			    int alen)
+{
+  struct search_query *squery = (struct search_query *) arg;
+  ares_channel channel = squery->channel;
+  char *s;
+
+  /* Stop searching unless we got a non-fatal error. */
+  if (status != ARES_ENODATA && status != ARES_ESERVFAIL
+      && status != ARES_ENOTFOUND)
+    end_squery(squery, status, abuf, alen);
+  else
+    {
+      /* Save the status if we were trying as-is. */
+      if (squery->trying_as_is)
+	squery->status_as_is = status;
+      if (squery->next_domain < channel->ndomains)
+	{
+	  /* Try the next domain. */
+	  status = cat_domain(squery->name,
+			      channel->domains[squery->next_domain], &s);
+	  if (status != ARES_SUCCESS)
+	    end_squery(squery, status, NULL, 0);
+	  else
+	    {
+	      squery->trying_as_is = 0;
+	      squery->next_domain++;
+	      ares_query(channel, s, squery->dnsclass, squery->type,
+			 search_callback, squery);
+	      free(s);
+	    }
+	}
+      else if (squery->status_as_is == -1)
+	{
+	  /* Try the name as-is at the end. */
+	  squery->trying_as_is = 1;
+	  ares_query(channel, squery->name, squery->dnsclass, squery->type,
+		     search_callback, squery);
+	}
+      else
+	end_squery(squery, squery->status_as_is, NULL, 0);
+    }
+}
+
+static void end_squery(struct search_query *squery, int status,
+		       unsigned char *abuf, int alen)
+{
+  squery->callback(squery->arg, status, abuf, alen);
+  free(squery->name);
+  free(squery);
+}
+
+/* Concatenate two domains. */
+static int cat_domain(const char *name, const char *domain, char **s)
+{
+  int nlen = strlen(name), dlen = strlen(domain);
+
+  *s = malloc(nlen + 1 + dlen + 1);
+  if (!*s)
+    return ARES_ENOMEM;
+  memcpy(*s, name, nlen);
+  (*s)[nlen] = '.';
+  memcpy(*s + nlen + 1, domain, dlen);
+  (*s)[nlen + 1 + dlen] = 0;
+  return ARES_SUCCESS;
+}
+
+/* Determine if this name only yields one query.  If it does, set *s to
+ * the string we should query, in an allocated buffer.  If not, set *s
+ * to NULL.
+ */
+static int single_domain(ares_channel channel, const char *name, char **s)
+{
+  int len = strlen(name);
+  const char *hostaliases;
+  FILE *fp;
+  char *line = NULL;
+  int linesize, status;
+  const char *p, *q;
+
+  /* If the name contains a trailing dot, then the single query is the name
+   * sans the trailing dot.
+   */
+  if (name[len - 1] == '.')
+    {
+      *s = strdup(name);
+      return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
+    }
+
+  if (!(channel->flags & ARES_FLAG_NOALIASES) && !strchr(name, '.'))
+    {
+      /* The name might be a host alias. */
+      hostaliases = getenv("HOSTALIASES");
+      if (hostaliases)
+	{
+	  fp = fopen(hostaliases, "r");
+	  if (fp)
+	    {
+	      while ((status = ares__read_line(fp, &line, &linesize))
+		     == ARES_SUCCESS)
+		{
+		  if (strncasecmp(line, name, len) != 0 ||
+		      !isspace((unsigned char)line[len]))
+		    continue;
+		  p = line + len;
+		  while (isspace((unsigned char)*p))
+		    p++;
+		  if (*p)
+		    {
+		      q = p + 1;
+		      while (*q && !isspace((unsigned char)*q))
+			q++;
+		      *s = malloc(q - p + 1);
+		      if (*s)
+			{
+			  memcpy(*s, p, q - p);
+			  (*s)[q - p] = 0;
+			}
+		      free(line);
+		      fclose(fp);
+		      return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
+		    }
+		}
+	      free(line);
+	      fclose(fp);
+	      if (status != ARES_SUCCESS)
+		return status;
+	    }
+	}
+    }
+
+  if (channel->flags & ARES_FLAG_NOSEARCH || channel->ndomains == 0)
+    {
+      /* No domain search to do; just try the name as-is. */
+      *s = strdup(name);
+      return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
+    }
+
+  *s = NULL;
+  return ARES_SUCCESS;
+}