Merge branch 'curl-upstream' into update-curl

Resolve all conflicts in favor of the upstream side.
We can re-apply specific changes later.

1 files changed, 448 insertions, 227 deletions

diff --git a/Utilities/cmcurl/lib/hostip.c b/Utilities/cmcurl/lib/hostip.c
index 83f1564..73b3f82 100644
--- a/Utilities/cmcurl/lib/hostip.c
+++ b/Utilities/cmcurl/lib/hostip.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2006, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -18,22 +18,10 @@
  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  * KIND, either express or implied.
  *
- * $Id$
  ***************************************************************************/
 
-#include "setup.h"
+#include "curl_setup.h"
 
-#include <string.h>
-
-#ifdef NEED_MALLOC_H
-#include <malloc.h>
-#endif
-#ifdef HAVE_SYS_TYPES_H
-#include <sys/types.h>
-#endif
-#ifdef HAVE_SYS_SOCKET_H
-#include <sys/socket.h>
-#endif
 #ifdef HAVE_NETINET_IN_H
 #include <netinet/in.h>
 #endif
@@ -43,21 +31,17 @@
 #ifdef HAVE_ARPA_INET_H
 #include <arpa/inet.h>
 #endif
-#ifdef HAVE_STDLIB_H
-#include <stdlib.h>     /* required for free() prototypes */
-#endif
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>     /* for the close() proto */
-#endif
-#ifdef  VMS
+#ifdef __VMS
 #include <in.h>
 #include <inet.h>
-#include <stdlib.h>
 #endif
 
 #ifdef HAVE_SETJMP_H
 #include <setjmp.h>
 #endif
+#ifdef HAVE_SIGNAL_H
+#include <signal.h>
+#endif
 
 #ifdef HAVE_PROCESS_H
 #include <process.h>
@@ -71,18 +55,21 @@
 #include "strerror.h"
 #include "url.h"
 #include "inet_ntop.h"
+#include "warnless.h"
 
 #define _MPRINTF_REPLACE /* use our functions only */
 #include <curl/mprintf.h>
 
-#if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL)
-#include "inet_ntoa_r.h"
-#endif
-
-#include "memory.h"
+#include "curl_memory.h"
 /* The last #include file should be: */
 #include "memdebug.h"
 
+#if defined(CURLRES_SYNCH) && \
+    defined(HAVE_ALARM) && defined(SIGALRM) && defined(HAVE_SIGSETJMP)
+/* alarm-based timeouts can only be used with all the dependencies satisfied */
+#define USE_ALARM_TIMEOUT
+#endif
+
 /*
  * hostip.c explained
  * ==================
@@ -111,13 +98,15 @@
  * hostip.c   - method-independent resolver functions and utility functions
  * hostasyn.c - functions for asynchronous name resolves
  * hostsyn.c  - functions for synchronous name resolves
- * hostares.c - functions for ares-using name resolves
- * hostthre.c - functions for threaded name resolves
  * hostip4.c  - ipv4-specific functions
  * hostip6.c  - ipv6-specific functions
  *
+ * The two asynchronous name resolver backends are implemented in:
+ * asyn-ares.c   - functions for ares-using name resolves
+ * asyn-thread.c - functions for threaded name resolves
+
  * The hostip.h is the united header file for all this. It defines the
- * CURLRES_* defines based on the config*.h and setup.h defines.
+ * CURLRES_* defines based on the config*.h and curl_setup.h defines.
  */
 
 /* These two symbols are for the global DNS cache */
@@ -130,21 +119,19 @@ static void freednsentry(void *freethis);
  * Curl_global_host_cache_init() initializes and sets up a global DNS cache.
  * Global DNS cache is general badness. Do not use. This will be removed in
  * a future version. Use the share interface instead!
+ *
+ * Returns a struct curl_hash pointer on success, NULL on failure.
  */
-void Curl_global_host_cache_init(void)
+struct curl_hash *Curl_global_host_cache_init(void)
 {
-  if (!host_cache_initialized) {
-    Curl_hash_init(&hostname_cache, 7, freednsentry);
-    host_cache_initialized = 1;
+  int rc = 0;
+  if(!host_cache_initialized) {
+    rc = Curl_hash_init(&hostname_cache, 7, Curl_hash_str,
+                        Curl_str_key_compare, freednsentry);
+    if(!rc)
+      host_cache_initialized = 1;
   }
-}
-
-/*
- * Return a pointer to the global cache
- */
-struct curl_hash *Curl_global_host_cache_get(void)
-{
-  return &hostname_cache;
+  return rc?NULL:&hostname_cache;
 }
 
 /*
@@ -152,7 +139,11 @@ struct curl_hash *Curl_global_host_cache_get(void)
  */
 void Curl_global_host_cache_dtor(void)
 {
-  if (host_cache_initialized) {
+  if(host_cache_initialized) {
+    /* first make sure that any custom "CURLOPT_RESOLVE" names are
+       cleared off */
+    Curl_hostcache_clean(NULL, &hostname_cache);
+    /* then free the remaining hash completely */
     Curl_hash_clean(&hostname_cache);
     host_cache_initialized = 0;
   }
@@ -163,46 +154,72 @@ void Curl_global_host_cache_dtor(void)
  */
 int Curl_num_addresses(const Curl_addrinfo *addr)
 {
-  int i;
-  for (i = 0; addr; addr = addr->ai_next, i++)
-    ;  /* empty loop */
+  int i = 0;
+  while(addr) {
+    addr = addr->ai_next;
+    i++;
+  }
   return i;
 }
 
 /*
  * Curl_printable_address() returns a printable version of the 1st address
- * given in the 'ip' argument. The result will be stored in the buf that is
+ * given in the 'ai' argument. The result will be stored in the buf that is
  * bufsize bytes big.
  *
  * If the conversion fails, it returns NULL.
  */
-const char *Curl_printable_address(const Curl_addrinfo *ip,
-                                   char *buf, size_t bufsize)
+const char *
+Curl_printable_address(const Curl_addrinfo *ai, char *buf, size_t bufsize)
 {
-  const void *ip4 = &((const struct sockaddr_in*)ip->ai_addr)->sin_addr;
-  int af = ip->ai_family;
-#ifdef CURLRES_IPV6
-  const void *ip6 = &((const struct sockaddr_in6*)ip->ai_addr)->sin6_addr;
-#else
-  const void *ip6 = NULL;
+  const struct sockaddr_in *sa4;
+  const struct in_addr *ipaddr4;
+#ifdef ENABLE_IPV6
+  const struct sockaddr_in6 *sa6;
+  const struct in6_addr *ipaddr6;
 #endif
 
-  return Curl_inet_ntop(af, af == AF_INET ? ip4 : ip6, buf, bufsize);
+  switch (ai->ai_family) {
+    case AF_INET:
+      sa4 = (const void *)ai->ai_addr;
+      ipaddr4 = &sa4->sin_addr;
+      return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr4, buf,
+                            bufsize);
+#ifdef ENABLE_IPV6
+    case AF_INET6:
+      sa6 = (const void *)ai->ai_addr;
+      ipaddr6 = &sa6->sin6_addr;
+      return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr6, buf,
+                            bufsize);
+#endif
+    default:
+      break;
+  }
+  return NULL;
 }
 
 /*
- * Return a hostcache id string for the providing host + port, to be used by
+ * Return a hostcache id string for the provided host + port, to be used by
  * the DNS caching.
  */
 static char *
-create_hostcache_id(const char *server, int port)
+create_hostcache_id(const char *name, int port)
 {
   /* create and return the new allocated entry */
-  return aprintf("%s:%d", server, port);
+  char *id = aprintf("%s:%d", name, port);
+  char *ptr = id;
+  if(ptr) {
+    /* lower case the name part */
+    while(*ptr && (*ptr != ':')) {
+      *ptr = (char)TOLOWER(*ptr);
+      ptr++;
+    }
+  }
+  return id;
 }
 
 struct hostcache_prune_data {
-  int cache_timeout;
+  long cache_timeout;
   time_t now;
 };
 
@@ -220,21 +237,14 @@ hostcache_timestamp_remove(void *datap, void *hc)
     (struct hostcache_prune_data *) datap;
   struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;
 
-  if ((data->now - c->timestamp < data->cache_timeout) ||
-      c->inuse) {
-    /* please don't remove */
-    return 0;
-  }
-
-  /* fine, remove */
-  return 1;
+  return !c->inuse && (data->now - c->timestamp >= data->cache_timeout);
 }
 
 /*
  * Prune the DNS cache. This assumes that a lock has already been taken.
  */
 static void
-hostcache_prune(struct curl_hash *hostcache, int cache_timeout, time_t now)
+hostcache_prune(struct curl_hash *hostcache, long cache_timeout, time_t now)
 {
   struct hostcache_prune_data user;
 
@@ -273,35 +283,30 @@ void Curl_hostcache_prune(struct SessionHandle *data)
     Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 }
 
+/*
+ * Check if the entry should be pruned. Assumes a locked cache.
+ */
 static int
 remove_entry_if_stale(struct SessionHandle *data, struct Curl_dns_entry *dns)
 {
   struct hostcache_prune_data user;
 
-  if( !dns || (data->set.dns_cache_timeout == -1) || !data->dns.hostcache)
-    /* cache forever means never prune, and NULL hostcache means
-       we can't do it */
+  if(!dns || (data->set.dns_cache_timeout == -1) || !data->dns.hostcache ||
+     dns->inuse)
+    /* cache forever means never prune, and NULL hostcache means we can't do
+       it, if it still is in use then we leave it */
     return 0;
 
   time(&user.now);
   user.cache_timeout = data->set.dns_cache_timeout;
 
-  if ( !hostcache_timestamp_remove(&user,dns) )
+  if(!hostcache_timestamp_remove(&user,dns) )
     return 0;
 
-  /* ok, we do need to clear the cache. although we need to remove just a
-     single entry we clean the entire hash, as no explicit delete function
-     is provided */
-  if(data->share)
-    Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
-
   Curl_hash_clean_with_criterium(data->dns.hostcache,
                                  (void *) &user,
                                  hostcache_timestamp_remove);
 
-  if(data->share)
-    Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
-
   return 1;
 }
 
@@ -313,6 +318,48 @@ remove_entry_if_stale(struct SessionHandle *data, struct Curl_dns_entry *dns)
 sigjmp_buf curl_jmpenv;
 #endif
 
+/*
+ * Curl_fetch_addr() fetches a 'Curl_dns_entry' already in the DNS cache.
+ *
+ * Curl_resolv() checks initially and multi_runsingle() checks each time
+ * it discovers the handle in the state WAITRESOLVE whether the hostname
+ * has already been resolved and the address has already been stored in
+ * the DNS cache. This short circuits waiting for a lot of pending
+ * lookups for the same hostname requested by different handles.
+ *
+ * Returns the Curl_dns_entry entry pointer or NULL if not in the cache.
+ */
+struct Curl_dns_entry *
+Curl_fetch_addr(struct connectdata *conn,
+                const char *hostname,
+                int port, int *stale)
+{
+  char *entry_id = NULL;
+  struct Curl_dns_entry *dns = NULL;
+  size_t entry_len;
+  struct SessionHandle *data = conn->data;
+
+  /* Create an entry id, based upon the hostname and port */
+  entry_id = create_hostcache_id(hostname, port);
+  /* If we can't create the entry id, fail */
+  if(!entry_id)
+    return dns;
+
+  entry_len = strlen(entry_id);
+
+  /* See if its already in our dns cache */
+  dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1);
+
+  /* free the allocated entry_id again */
+  free(entry_id);
+
+  /* See whether the returned entry is stale. Done before we release lock */
+  *stale = remove_entry_if_stale(data, dns);
+  if(*stale)
+    dns = NULL; /* the memory deallocation is being handled by the hash */
+
+  return dns;
+}
 
 /*
  * Curl_cache_addr() stores a 'Curl_addrinfo' struct in the DNS cache.
@@ -333,43 +380,40 @@ Curl_cache_addr(struct SessionHandle *data,
   size_t entry_len;
   struct Curl_dns_entry *dns;
   struct Curl_dns_entry *dns2;
-  time_t now;
 
   /* Create an entry id, based upon the hostname and port */
   entry_id = create_hostcache_id(hostname, port);
   /* If we can't create the entry id, fail */
-  if (!entry_id)
+  if(!entry_id)
     return NULL;
   entry_len = strlen(entry_id);
 
   /* Create a new cache entry */
-  dns = (struct Curl_dns_entry *) calloc(sizeof(struct Curl_dns_entry), 1);
-  if (!dns) {
+  dns = calloc(1, sizeof(struct Curl_dns_entry));
+  if(!dns) {
     free(entry_id);
     return NULL;
   }
 
   dns->inuse = 0;   /* init to not used */
   dns->addr = addr; /* this is the address(es) */
+  time(&dns->timestamp);
+  if(dns->timestamp == 0)
+    dns->timestamp = 1;   /* zero indicates that entry isn't in hash table */
 
-  /* Store the resolved data in our DNS cache. This function may return a
-     pointer to an existing struct already present in the hash, and it may
-     return the same argument we pass in. Make no assumptions. */
+  /* Store the resolved data in our DNS cache. */
   dns2 = Curl_hash_add(data->dns.hostcache, entry_id, entry_len+1,
                        (void *)dns);
   if(!dns2) {
-    /* Major badness, run away. */
     free(dns);
     free(entry_id);
     return NULL;
   }
-  time(&now);
-  dns = dns2;
 
-  dns->timestamp = now; /* used now */
+  dns = dns2;
   dns->inuse++;         /* mark entry as in-use */
 
-  /* free the allocated entry_id again */
+  /* free the allocated entry_id */
   free(entry_id);
 
   return dns;
@@ -385,6 +429,10 @@ Curl_cache_addr(struct SessionHandle *data,
  * function is used. You MUST call Curl_resolv_unlock() later (when you're
  * done using this struct) to decrease the counter again.
  *
+ * In debug mode, we specifically test for an interface name "LocalHost"
+ * and resolve "localhost" instead as a means to permit test cases
+ * to connect to a local test server with any host name.
+ *
  * Return codes:
  *
  * CURLRESOLV_ERROR   (-1) = error, no pointer
@@ -397,75 +445,59 @@ int Curl_resolv(struct connectdata *conn,
                 int port,
                 struct Curl_dns_entry **entry)
 {
-  char *entry_id = NULL;
   struct Curl_dns_entry *dns = NULL;
-  size_t entry_len;
-  int wait;
   struct SessionHandle *data = conn->data;
   CURLcode result;
-  int rc;
-  *entry = NULL;
-
-#ifdef HAVE_SIGSETJMP
-  /* this allows us to time-out from the name resolver, as the timeout
-     will generate a signal and we will siglongjmp() from that here */
-  if(!data->set.no_signal) {
-    if (sigsetjmp(curl_jmpenv, 1)) {
-      /* this is coming from a siglongjmp() */
-      failf(data, "name lookup timed out");
-      return CURLRESOLV_ERROR;
-    }
-  }
-#endif
-
-  /* Create an entry id, based upon the hostname and port */
-  entry_id = create_hostcache_id(hostname, port);
-  /* If we can't create the entry id, fail */
-  if (!entry_id)
-    return CURLRESOLV_ERROR;
+  int stale, rc = CURLRESOLV_ERROR; /* default to failure */
 
-  entry_len = strlen(entry_id);
+  *entry = NULL;
 
   if(data->share)
     Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 
-  /* See if its already in our dns cache */
-  dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1);
+  dns = Curl_fetch_addr(conn, hostname, port, &stale);
 
-  if(data->share)
-    Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
+  infof(data, "Hostname was %sfound in DNS cache\n", dns||stale?"":"NOT ");
+  if(stale)
+    infof(data, "Hostname in DNS cache was stale, zapped\n");
 
-  /* free the allocated entry_id again */
-  free(entry_id);
 
-  /* See whether the returned entry is stale. Deliberately done after the
-     locked block */
-  if ( remove_entry_if_stale(data,dns) )
-    dns = NULL; /* the memory deallocation is being handled by the hash */
+  if(dns) {
+    dns->inuse++; /* we use it! */
+    rc = CURLRESOLV_RESOLVED;
+  }
 
-  rc = CURLRESOLV_ERROR; /* default to failure */
+  if(data->share)
+    Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 
-  if (!dns) {
+  if(!dns) {
     /* The entry was not in the cache. Resolve it to IP address */
 
     Curl_addrinfo *addr;
+    int respwait;
 
     /* Check what IP specifics the app has requested and if we can provide it.
      * If not, bail out. */
-    if(!Curl_ipvalid(data))
+    if(!Curl_ipvalid(conn))
       return CURLRESOLV_ERROR;
 
-    /* If Curl_getaddrinfo() returns NULL, 'wait' might be set to a non-zero
-       value indicating that we need to wait for the response to the resolve
-       call */
-    addr = Curl_getaddrinfo(conn, hostname, port, &wait);
+    /* If Curl_getaddrinfo() returns NULL, 'respwait' might be set to a
+       non-zero value indicating that we need to wait for the response to the
+       resolve call */
+    addr = Curl_getaddrinfo(conn,
+#ifdef DEBUGBUILD
+                            (data->set.str[STRING_DEVICE]
+                             && !strcmp(data->set.str[STRING_DEVICE],
+                                        "LocalHost"))?"localhost":
+#endif
+                            hostname, port, &respwait);
 
-    if (!addr) {
-      if(wait) {
+    if(!addr) {
+      if(respwait) {
         /* the response to our resolve call will come asynchronously at
            a later time, good or bad */
         /* First, check that we haven't received the info by now */
-        result = Curl_is_resolved(conn, &dns);
+        result = Curl_resolver_is_resolved(conn, &dns);
         if(result) /* error detected */
           return CURLRESOLV_ERROR;
         if(dns)
@@ -491,35 +523,217 @@ int Curl_resolv(struct connectdata *conn,
         rc = CURLRESOLV_RESOLVED;
     }
   }
-  else {
-    if(data->share)
-      Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
-    dns->inuse++; /* we use it! */
-    if(data->share)
-      Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
-    rc = CURLRESOLV_RESOLVED;
-  }
 
   *entry = dns;
 
   return rc;
 }
 
+#ifdef USE_ALARM_TIMEOUT
+/*
+ * This signal handler jumps back into the main libcurl code and continues
+ * execution.  This effectively causes the remainder of the application to run
+ * within a signal handler which is nonportable and could lead to problems.
+ */
+static
+RETSIGTYPE alarmfunc(int sig)
+{
+  /* this is for "-ansi -Wall -pedantic" to stop complaining!   (rabe) */
+  (void)sig;
+  siglongjmp(curl_jmpenv, 1);
+  return;
+}
+#endif /* USE_ALARM_TIMEOUT */
+
+/*
+ * Curl_resolv_timeout() is the same as Curl_resolv() but specifies a
+ * timeout.  This function might return immediately if we're using asynch
+ * resolves. See the return codes.
+ *
+ * The cache entry we return will get its 'inuse' counter increased when this
+ * function is used. You MUST call Curl_resolv_unlock() later (when you're
+ * done using this struct) to decrease the counter again.
+ *
+ * If built with a synchronous resolver and use of signals is not
+ * disabled by the application, then a nonzero timeout will cause a
+ * timeout after the specified number of milliseconds. Otherwise, timeout
+ * is ignored.
+ *
+ * Return codes:
+ *
+ * CURLRESOLV_TIMEDOUT(-2) = warning, time too short or previous alarm expired
+ * CURLRESOLV_ERROR   (-1) = error, no pointer
+ * CURLRESOLV_RESOLVED (0) = OK, pointer provided
+ * CURLRESOLV_PENDING  (1) = waiting for response, no pointer
+ */
+
+int Curl_resolv_timeout(struct connectdata *conn,
+                        const char *hostname,
+                        int port,
+                        struct Curl_dns_entry **entry,
+                        long timeoutms)
+{
+#ifdef USE_ALARM_TIMEOUT
+#ifdef HAVE_SIGACTION
+  struct sigaction keep_sigact;   /* store the old struct here */
+  volatile bool keep_copysig = FALSE; /* wether old sigact has been saved */
+  struct sigaction sigact;
+#else
+#ifdef HAVE_SIGNAL
+  void (*keep_sigact)(int);       /* store the old handler here */
+#endif /* HAVE_SIGNAL */
+#endif /* HAVE_SIGACTION */
+  volatile long timeout;
+  volatile unsigned int prev_alarm = 0;
+  struct SessionHandle *data = conn->data;
+#endif /* USE_ALARM_TIMEOUT */
+  int rc;
+
+  *entry = NULL;
+
+  if(timeoutms < 0)
+    /* got an already expired timeout */
+    return CURLRESOLV_TIMEDOUT;
+
+#ifdef USE_ALARM_TIMEOUT
+  if(data->set.no_signal)
+    /* Ignore the timeout when signals are disabled */
+    timeout = 0;
+  else
+    timeout = timeoutms;
+
+  if(!timeout)
+    /* USE_ALARM_TIMEOUT defined, but no timeout actually requested */
+    return Curl_resolv(conn, hostname, port, entry);
+
+  if(timeout < 1000)
+    /* The alarm() function only provides integer second resolution, so if
+       we want to wait less than one second we must bail out already now. */
+    return CURLRESOLV_TIMEDOUT;
+
+  /*************************************************************
+   * Set signal handler to catch SIGALRM
+   * Store the old value to be able to set it back later!
+   *************************************************************/
+#ifdef HAVE_SIGACTION
+  sigaction(SIGALRM, NULL, &sigact);
+  keep_sigact = sigact;
+  keep_copysig = TRUE; /* yes, we have a copy */
+  sigact.sa_handler = alarmfunc;
+#ifdef SA_RESTART
+  /* HPUX doesn't have SA_RESTART but defaults to that behaviour! */
+  sigact.sa_flags &= ~SA_RESTART;
+#endif
+  /* now set the new struct */
+  sigaction(SIGALRM, &sigact, NULL);
+#else /* HAVE_SIGACTION */
+  /* no sigaction(), revert to the much lamer signal() */
+#ifdef HAVE_SIGNAL
+  keep_sigact = signal(SIGALRM, alarmfunc);
+#endif
+#endif /* HAVE_SIGACTION */
+
+  /* alarm() makes a signal get sent when the timeout fires off, and that
+     will abort system calls */
+  prev_alarm = alarm(curlx_sltoui(timeout/1000L));
+
+  /* This allows us to time-out from the name resolver, as the timeout
+     will generate a signal and we will siglongjmp() from that here.
+     This technique has problems (see alarmfunc).
+     This should be the last thing we do before calling Curl_resolv(),
+     as otherwise we'd have to worry about variables that get modified
+     before we invoke Curl_resolv() (and thus use "volatile"). */
+  if(sigsetjmp(curl_jmpenv, 1)) {
+    /* this is coming from a siglongjmp() after an alarm signal */
+    failf(data, "name lookup timed out");
+    rc = CURLRESOLV_ERROR;
+    goto clean_up;
+  }
+
+#else
+#ifndef CURLRES_ASYNCH
+  if(timeoutms)
+    infof(conn->data, "timeout on name lookup is not supported\n");
+#else
+  (void)timeoutms; /* timeoutms not used with an async resolver */
+#endif
+#endif /* USE_ALARM_TIMEOUT */
+
+  /* Perform the actual name resolution. This might be interrupted by an
+   * alarm if it takes too long.
+   */
+  rc = Curl_resolv(conn, hostname, port, entry);
+
+#ifdef USE_ALARM_TIMEOUT
+clean_up:
+
+  if(!prev_alarm)
+    /* deactivate a possibly active alarm before uninstalling the handler */
+    alarm(0);
+
+#ifdef HAVE_SIGACTION
+  if(keep_copysig) {
+    /* we got a struct as it looked before, now put that one back nice
+       and clean */
+    sigaction(SIGALRM, &keep_sigact, NULL); /* put it back */
+  }
+#else
+#ifdef HAVE_SIGNAL
+  /* restore the previous SIGALRM handler */
+  signal(SIGALRM, keep_sigact);
+#endif
+#endif /* HAVE_SIGACTION */
+
+  /* switch back the alarm() to either zero or to what it was before minus
+     the time we spent until now! */
+  if(prev_alarm) {
+    /* there was an alarm() set before us, now put it back */
+    unsigned long elapsed_ms = Curl_tvdiff(Curl_tvnow(), conn->created);
+
+    /* the alarm period is counted in even number of seconds */
+    unsigned long alarm_set = prev_alarm - elapsed_ms/1000;
+
+    if(!alarm_set ||
+       ((alarm_set >= 0x80000000) && (prev_alarm < 0x80000000)) ) {
+      /* if the alarm time-left reached zero or turned "negative" (counted
+         with unsigned values), we should fire off a SIGALRM here, but we
+         won't, and zero would be to switch it off so we never set it to
+         less than 1! */
+      alarm(1);
+      rc = CURLRESOLV_TIMEDOUT;
+      failf(data, "Previous alarm fired off!");
+    }
+    else
+      alarm((unsigned int)alarm_set);
+  }
+#endif /* USE_ALARM_TIMEOUT */
+
+  return rc;
+}
+
 /*
  * Curl_resolv_unlock() unlocks the given cached DNS entry. When this has been
  * made, the struct may be destroyed due to pruning. It is important that only
  * one unlock is made for each Curl_resolv() call.
+ *
+ * May be called with 'data' == NULL for global cache.
  */
 void Curl_resolv_unlock(struct SessionHandle *data, struct Curl_dns_entry *dns)
 {
-  curlassert(dns && (dns->inuse>0));
+  DEBUGASSERT(dns && (dns->inuse>0));
 
-  if(data->share)
+  if(data && data->share)
     Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 
   dns->inuse--;
+  /* only free if nobody is using AND it is not in hostcache (timestamp ==
+     0) */
+  if(dns->inuse == 0 && dns->timestamp == 0) {
+    Curl_freeaddrinfo(dns->addr);
+    free(dns);
+  }
 
-  if(data->share)
+  if(data && data->share)
     Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 }
 
@@ -530,9 +744,12 @@ static void freednsentry(void *freethis)
 {
   struct Curl_dns_entry *p = (struct Curl_dns_entry *) freethis;
 
-  Curl_freeaddrinfo(p->addr);
-
-  free(p);
+  /* mark the entry as not in hostcache */
+  p->timestamp = 0;
+  if(p->inuse == 0) {
+    Curl_freeaddrinfo(p->addr);
+    free(p);
+  }
 }
 
 /*
@@ -540,97 +757,101 @@ static void freednsentry(void *freethis)
  */
 struct curl_hash *Curl_mk_dnscache(void)
 {
-  return Curl_hash_alloc(7, freednsentry);
+  return Curl_hash_alloc(7, Curl_hash_str, Curl_str_key_compare, freednsentry);
 }
 
-#ifdef CURLRES_ADDRINFO_COPY
+static int hostcache_inuse(void *data, void *hc)
+{
+  struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;
 
-/* align on even 64bit boundaries */
-#define MEMALIGN(x) ((x)+(8-(((unsigned long)(x))&0x7)))
+  if(c->inuse == 1)
+    Curl_resolv_unlock(data, c);
+
+  return 1; /* free all entries */
+}
 
 /*
- * Curl_addrinfo_copy() performs a "deep" copy of a hostent into a buffer and
- * returns a pointer to the malloc()ed copy. You need to call free() on the
- * returned buffer when you're done with it.
+ * Curl_hostcache_clean()
+ *
+ * This _can_ be called with 'data' == NULL but then of course no locking
+ * can be done!
  */
-Curl_addrinfo *Curl_addrinfo_copy(const void *org, int port)
-{
-  const struct hostent *orig = org;
 
-  return Curl_he2ai(orig, port);
+void Curl_hostcache_clean(struct SessionHandle *data,
+                          struct curl_hash *hash)
+{
+  /* Entries added to the hostcache with the CURLOPT_RESOLVE function are
+   * still present in the cache with the inuse counter set to 1. Detect them
+   * and cleanup!
+   */
+  Curl_hash_clean_with_criterium(hash, data, hostcache_inuse);
 }
-#endif /* CURLRES_ADDRINFO_COPY */
 
-/***********************************************************************
- * Only for plain-ipv4 and c-ares builds
- **********************************************************************/
 
-#if defined(CURLRES_IPV4) || defined(CURLRES_ARES)
-/*
- * This is a function for freeing name information in a protocol independent
- * way.
- */
-void Curl_freeaddrinfo(Curl_addrinfo *ai)
+CURLcode Curl_loadhostpairs(struct SessionHandle *data)
 {
-  Curl_addrinfo *next;
+  struct curl_slist *hostp;
+  char hostname[256];
+  char address[256];
+  int port;
+
+  for(hostp = data->change.resolve; hostp; hostp = hostp->next ) {
+    if(!hostp->data)
+      continue;
+    if(hostp->data[0] == '-') {
+      /* TODO: mark an entry for removal */
+    }
+    else if(3 == sscanf(hostp->data, "%255[^:]:%d:%255s", hostname, &port,
+                        address)) {
+      struct Curl_dns_entry *dns;
+      Curl_addrinfo *addr;
+      char *entry_id;
+      size_t entry_len;
+
+      addr = Curl_str2addr(address, port);
+      if(!addr) {
+        infof(data, "Resolve %s found illegal!\n", hostp->data);
+        continue;
+      }
 
-  /* walk over the list and free all entries */
-  while(ai) {
-    next = ai->ai_next;
-    free(ai);
-    ai = next;
-  }
-}
+      /* Create an entry id, based upon the hostname and port */
+      entry_id = create_hostcache_id(hostname, port);
+      /* If we can't create the entry id, fail */
+      if(!entry_id) {
+        Curl_freeaddrinfo(addr);
+        return CURLE_OUT_OF_MEMORY;
+      }
 
-struct namebuf {
-  struct hostent hostentry;
-  char *h_addr_list[2];
-  struct in_addr addrentry;
-  char h_name[16]; /* 123.123.123.123 = 15 letters is maximum */
-};
+      entry_len = strlen(entry_id);
 
-/*
- * Curl_ip2addr() takes a 32bit ipv4 internet address as input parameter
- * together with a pointer to the string version of the address, and it
- * returns a Curl_addrinfo chain filled in correctly with information for this
- * address/host.
- *
- * The input parameters ARE NOT checked for validity but they are expected
- * to have been checked already when this is called.
- */
-Curl_addrinfo *Curl_ip2addr(in_addr_t num, const char *hostname, int port)
-{
-  Curl_addrinfo *ai;
-  struct hostent *h;
-  struct in_addr *addrentry;
-  struct namebuf buffer;
-  struct namebuf *buf = &buffer;
-
-  h = &buf->hostentry;
-  h->h_addr_list = &buf->h_addr_list[0];
-  addrentry = &buf->addrentry;
-#ifdef _CRAY
-  /* On UNICOS, s_addr is a bit field and for some reason assigning to it
-   * doesn't work.  There must be a better fix than this ugly hack.
-   */
-  memcpy(addrentry, &num, SIZEOF_in_addr);
-#else
-  addrentry->s_addr = num;
-#endif
-  h->h_addr_list[0] = (char*)addrentry;
-  h->h_addr_list[1] = NULL;
-  h->h_addrtype = AF_INET;
-  h->h_length = sizeof(*addrentry);
-  h->h_name = &buf->h_name[0];
-  h->h_aliases = NULL;
+      if(data->share)
+        Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 
-  /* Now store the dotted version of the address */
-  snprintf((char *)h->h_name, 16, "%s", hostname);
+      /* See if its already in our dns cache */
+      dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1);
 
-  ai = Curl_he2ai(h, port);
+      /* free the allocated entry_id again */
+      free(entry_id);
 
-  return ai;
-}
-#endif
+      if(!dns)
+        /* if not in the cache already, put this host in the cache */
+        dns = Curl_cache_addr(data, addr, hostname, port);
+      else
+        /* this is a duplicate, free it again */
+        Curl_freeaddrinfo(addr);
+
+      if(data->share)
+        Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 
+      if(!dns) {
+        Curl_freeaddrinfo(addr);
+        return CURLE_OUT_OF_MEMORY;
+      }
+      infof(data, "Added %s:%d:%s to DNS cache\n",
+            hostname, port, address);
+    }
+  }
+  data->change.resolve = NULL; /* dealt with now */
 
+  return CURLE_OK;
+}