Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 316 insertions, 0 deletions

diff --git a/src/c-ares/ares_search.c b/src/c-ares/ares_search.c
new file mode 100644
index 000000000..68e852574
--- /dev/null
+++ b/src/c-ares/ares_search.c
@@ -0,0 +1,316 @@
+
+/* 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.
+ */
+
+#include "ares_setup.h"
+
+#ifdef HAVE_STRINGS_H
+#  include <strings.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 */
+  int timeouts;                 /* number of timeouts we saw for this request */
+  int ever_got_nodata;          /* did we ever get ARES_ENODATA along the way? */
+};
+
+static void search_callback(void *arg, int status, int timeouts,
+                            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_TESTABLE 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, 0, NULL, 0);
+      return;
+    }
+  if (s)
+    {
+      ares_query(channel, s, dnsclass, type, callback, arg);
+      ares_free(s);
+      return;
+    }
+
+  /* Allocate a search_query structure to hold the state necessary for
+   * doing multiple lookups.
+   */
+  squery = ares_malloc(sizeof(struct search_query));
+  if (!squery)
+    {
+      callback(arg, ARES_ENOMEM, 0, NULL, 0);
+      return;
+    }
+  squery->channel = channel;
+  squery->name = ares_strdup(name);
+  if (!squery->name)
+    {
+      ares_free(squery);
+      callback(arg, ARES_ENOMEM, 0, NULL, 0);
+      return;
+    }
+  squery->dnsclass = dnsclass;
+  squery->type = type;
+  squery->status_as_is = -1;
+  squery->callback = callback;
+  squery->arg = arg;
+  squery->timeouts = 0;
+  squery->ever_got_nodata = 0;
+
+  /* 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);
+          ares_free(s);
+        }
+      else
+      {
+        /* failed, free the malloc()ed memory */
+        ares_free(squery->name);
+        ares_free(squery);
+        callback(arg, status, 0, NULL, 0);
+      }
+    }
+}
+
+static void search_callback(void *arg, int status, int timeouts,
+                            unsigned char *abuf, int alen)
+{
+  struct search_query *squery = (struct search_query *) arg;
+  ares_channel channel = squery->channel;
+  char *s;
+
+  squery->timeouts += timeouts;
+
+  /* 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 we ever get ARES_ENODATA along the way, record that; if the search
+       * should run to the very end and we got at least one ARES_ENODATA,
+       * then callers like ares_gethostbyname() may want to try a T_A search
+       * even if the last domain we queried for T_AAAA resource records
+       * returned ARES_ENOTFOUND.
+       */
+      if (status == ARES_ENODATA)
+        squery->ever_got_nodata = 1;
+
+      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);
+              ares_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 {
+        if (squery->status_as_is == ARES_ENOTFOUND && squery->ever_got_nodata) {
+          end_squery(squery, ARES_ENODATA, NULL, 0);
+        }
+        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, squery->timeouts, abuf, alen);
+  ares_free(squery->name);
+  ares_free(squery);
+}
+
+/* Concatenate two domains. */
+static int cat_domain(const char *name, const char *domain, char **s)
+{
+  size_t nlen = strlen(name);
+  size_t dlen = strlen(domain);
+
+  *s = ares_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_TESTABLE int single_domain(ares_channel channel, const char *name, char **s)
+{
+  size_t len = strlen(name);
+  const char *hostaliases;
+  FILE *fp;
+  char *line = NULL;
+  int status;
+  size_t linesize;
+  const char *p, *q;
+  int error;
+
+  /* If the name contains a trailing dot, then the single query is the name
+   * sans the trailing dot.
+   */
+  if ((len > 0) && (name[len - 1] == '.'))
+    {
+      *s = ares_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(line[len]))
+                    continue;
+                  p = line + len;
+                  while (ISSPACE(*p))
+                    p++;
+                  if (*p)
+                    {
+                      q = p + 1;
+                      while (*q && !ISSPACE(*q))
+                        q++;
+                      *s = ares_malloc(q - p + 1);
+                      if (*s)
+                        {
+                          memcpy(*s, p, q - p);
+                          (*s)[q - p] = 0;
+                        }
+                      ares_free(line);
+                      fclose(fp);
+                      return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
+                    }
+                }
+              ares_free(line);
+              fclose(fp);
+              if (status != ARES_SUCCESS && status != ARES_EOF)
+                return status;
+            }
+          else
+            {
+              error = ERRNO;
+              switch(error)
+                {
+                case ENOENT:
+                case ESRCH:
+                  break;
+                default:
+                  DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
+                                 error, strerror(error)));
+                  DEBUGF(fprintf(stderr, "Error opening file: %s\n",
+                                 hostaliases));
+                  *s = NULL;
+                  return ARES_EFILE;
+                }
+            }
+        }
+    }
+
+  if (channel->flags & ARES_FLAG_NOSEARCH || channel->ndomains == 0)
+    {
+      /* No domain search to do; just try the name as-is. */
+      *s = ares_strdup(name);
+      return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
+    }
+
+  *s = NULL;
+  return ARES_SUCCESS;
+}