[PATCH] 7006496: Use modern Windows API to retrieve OS DNS servers
Anuraag Agrawal
anuraaga at gmail.com
Fri Dec 6 06:33:56 UTC 2019
Hi Aleksei,
Thanks for the suggestion! Indeed I didn't consider the implication of
duplicates on the pre-allocation, this is a simpler approach. I've
incorporated it into the patch.
Inline patch follows
diff --git
a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
index 2250b3158e..9e7c47bd44 100644
---
a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
+++
b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
@@ -25,9 +25,10 @@
package sun.net.dns;
+import java.util.ArrayList;
import java.util.List;
-import java.util.LinkedList;
import java.util.StringTokenizer;
+import java.util.concurrent.TimeUnit;
/*
* An implementation of sun.net.ResolverConfiguration for Windows.
@@ -50,30 +51,57 @@ public class ResolverConfigurationImpl
// Cache timeout (120 seconds) - should be converted into property
// or configured as preference in the future.
- private static final int TIMEOUT = 120000;
+ private static final long TIMEOUT_NANOS =
TimeUnit.SECONDS.toNanos(120);
// DNS suffix list and name servers populated by native method
private static String os_searchlist;
private static String os_nameservers;
// Cached lists
- private static LinkedList<String> searchlist;
- private static LinkedList<String> nameservers;
+ private static ArrayList<String> searchlist;
+ private static ArrayList<String> nameservers;
+
+ // Parse string that consists of token delimited by space
+ // and return ArrayList. Refer to ResolverConfigurationImpl.c and
+ // strappend to see how the string is created.
+ private ArrayList<String> stringToList(String str) {
+ // String is delimited by space.
+ StringTokenizer st = new StringTokenizer(str, " ");
+ ArrayList<String> l = new ArrayList<>(st.countTokens());
+ while (st.hasMoreTokens()) {
+ String s = st.nextToken();
+ if (!l.contains(s)) {
+ l.add(s);
+ }
+ }
+ l.trimToSize();
+ return l;
+ }
- // Parse string that consists of token delimited by space or commas
- // and return LinkedHashMap
- private LinkedList<String> stringToList(String str) {
- LinkedList<String> ll = new LinkedList<>();
+ // Parse string that consists of token delimited by space
+ // and return ArrayList. Refer to ResolverConfigurationImpl.c and
+ // strappend to see how the string is created.
+ // In addition to splitting the string, converts IPv6 addresses to
+ // BSD-style.
+ private ArrayList<String> addressesToList(String str) {
+ // String is delimited by space
+ StringTokenizer st = new StringTokenizer(str, " ");
+ ArrayList<String> l = new ArrayList<>(st.countTokens());
- // comma and space are valid delimiters
- StringTokenizer st = new StringTokenizer(str, ", ");
while (st.hasMoreTokens()) {
String s = st.nextToken();
- if (!ll.contains(s)) {
- ll.add(s);
+ if (!s.isEmpty()) {
+ if (s.indexOf(':') >= 0 && s.charAt(0) != '[') {
+ // Not BSD style
+ s = '[' + s + ']';
+ }
+ if (!l.contains(s)) {
+ l.add(s);
+ }
}
}
- return ll;
+ l.trimToSize();
+ return l;
}
// Load DNS configuration from OS
@@ -81,28 +109,34 @@ public class ResolverConfigurationImpl
private void loadConfig() {
assert Thread.holdsLock(lock);
- // if address have changed then DNS probably changed as well;
- // otherwise check if cached settings have expired.
- //
+ // A change in the network address of the machine usually indicates
+ // a change in DNS configuration too so we always refresh the
config
+ // after such a change.
if (changed) {
changed = false;
} else {
+ // Otherwise we refresh if TIMEOUT_NANOS has passed since last
+ // load.
if (lastRefresh >= 0) {
- long currTime = System.currentTimeMillis();
- if ((currTime - lastRefresh) < TIMEOUT) {
+ long currTime = System.nanoTime();
+ if ((currTime - lastRefresh) < TIMEOUT_NANOS) {
return;
}
}
}
- // load DNS configuration, update timestamp, create
- // new HashMaps from the loaded configuration
- //
+ // Native code that uses Windows API to find out the DNS server
+ // addresses and search suffixes. It builds a space-delimited
string
+ // of nameservers and domain suffixes and sets them to the static
+ // os_nameservers and os_searchlist. We then split these into Java
+ // Lists here.
loadDNSconfig0();
- lastRefresh = System.currentTimeMillis();
+ // Record the time of update and refresh the lists of addresses /
+ // domain suffixes.
+ lastRefresh = System.nanoTime();
searchlist = stringToList(os_searchlist);
- nameservers = stringToList(os_nameservers);
+ nameservers = addressesToList(os_nameservers);
os_searchlist = null; // can be GC'ed
os_nameservers = null;
}
diff --git a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
index f2368bafcb..297a1561ef 100644
--- a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
+++ b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
@@ -73,8 +73,8 @@ const int MAX_TRIES = 3;
* for each adapter on the system. Returned in *adapters.
* Buffer is malloc'd and must be freed (unless error returned)
*/
-static int getAdapters (JNIEnv *env, IP_ADAPTER_ADDRESSES **adapters) {
- DWORD ret, flags;
+int getAdapters (JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES **adapters) {
+ DWORD ret;
IP_ADAPTER_ADDRESSES *adapterInfo;
ULONG len;
int try;
@@ -87,9 +87,6 @@ static int getAdapters (JNIEnv *env, IP_ADAPTER_ADDRESSES
**adapters) {
}
len = BUFF_SIZE;
- flags = GAA_FLAG_SKIP_DNS_SERVER;
- flags |= GAA_FLAG_SKIP_MULTICAST;
- flags |= GAA_FLAG_INCLUDE_PREFIX;
ret = GetAdaptersAddresses(AF_UNSPEC, flags, NULL, adapterInfo, &len);
for (try = 0; ret == ERROR_BUFFER_OVERFLOW && try < MAX_TRIES; ++try) {
@@ -240,7 +237,7 @@ static int ipinflen = 2048;
*/
int getAllInterfacesAndAddresses (JNIEnv *env, netif **netifPP)
{
- DWORD ret;
+ DWORD ret, flags;
MIB_IPADDRTABLE *tableP;
IP_ADAPTER_ADDRESSES *ptr, *adapters=NULL;
ULONG len=ipinflen, count=0;
@@ -296,7 +293,11 @@ int getAllInterfacesAndAddresses (JNIEnv *env, netif
**netifPP)
}
}
free(tableP);
- ret = getAdapters (env, &adapters);
+
+ flags = GAA_FLAG_SKIP_DNS_SERVER;
+ flags |= GAA_FLAG_SKIP_MULTICAST;
+ flags |= GAA_FLAG_INCLUDE_PREFIX;
+ ret = getAdapters (env, flags, &adapters);
if (ret != ERROR_SUCCESS) {
goto err;
}
diff --git
a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
index 13b28044a5..83100aa9ad 100644
--- a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
+++ b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
@@ -30,6 +30,7 @@
#include <iprtrmib.h>
#include <time.h>
#include <assert.h>
+#include <winsock2.h>
#include <iphlpapi.h>
#include "jni_util.h"
@@ -48,6 +49,8 @@
static jfieldID searchlistID;
static jfieldID nameserversID;
+extern int getAdapters(JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES
**adapters);
+
/*
* Utility routine to append s2 to s1 with a space delimiter.
* strappend(s1="abc", "def") => "abc def"
@@ -72,29 +75,19 @@ void strappend(char *s1, char *s2) {
}
/*
- * Windows 2000/XP
- *
- * Use registry approach based on settings described in Appendix C
- * of "Microsoft Windows 2000 TCP/IP Implementation Details".
- *
- * DNS suffix list is obtained from SearchList registry setting. If
- * this is not specified we compile suffix list based on the
- * per-connection domain suffix.
- *
- * DNS name servers and domain settings are on a per-connection
- * basic. We therefore enumerate the network adapters to get the
- * names of each adapter and then query the corresponding registry
- * settings to obtain NameServer/DhcpNameServer and Domain/DhcpDomain.
+ * Use DNS server addresses returned by GetAdaptersAddresses for currently
+ * active interfaces.
*/
-static int loadConfig(char *sl, char *ns) {
- IP_ADAPTER_INFO *adapterP;
- ULONG size;
- DWORD ret;
+static int loadConfig(JNIEnv *env, char *sl, char *ns) {
+ IP_ADAPTER_ADDRESSES *adapters, *adapter;
+ IP_ADAPTER_DNS_SERVER_ADDRESS *dnsServer;
+ SOCKADDR *address;
+ IP_ADAPTER_DNS_SUFFIX *suffix;
+ DWORD ret, flags;
DWORD dwLen;
ULONG ulType;
char result[MAX_STR_LEN];
HANDLE hKey;
- int gotSearchList = 0;
/*
* First see if there is a global suffix list specified.
@@ -112,122 +105,58 @@ static int loadConfig(char *sl, char *ns) {
assert(ulType == REG_SZ);
if (strlen(result) > 0) {
strappend(sl, result);
- gotSearchList = 1;
}
}
RegCloseKey(hKey);
}
- /*
- * Ask the IP Helper library to enumerate the adapters
- */
- size = sizeof(IP_ADAPTER_INFO);
- adapterP = (IP_ADAPTER_INFO *)malloc(size);
- if (adapterP == NULL) {
- return STS_ERROR;
- }
- ret = GetAdaptersInfo(adapterP, &size);
- if (ret == ERROR_BUFFER_OVERFLOW) {
- IP_ADAPTER_INFO *newAdapterP = (IP_ADAPTER_INFO
*)realloc(adapterP, size);
- if (newAdapterP == NULL) {
- free(adapterP);
- return STS_ERROR;
- }
- adapterP = newAdapterP;
- ret = GetAdaptersInfo(adapterP, &size);
+ // We only need DNS server addresses so skip everything else.
+ flags = GAA_FLAG_SKIP_UNICAST;
+ flags |= GAA_FLAG_SKIP_ANYCAST;
+ flags |= GAA_FLAG_SKIP_MULTICAST;
+ flags |= GAA_FLAG_SKIP_FRIENDLY_NAME;
+ ret = getAdapters(env, flags, &adapters);
+ if (ret != ERROR_SUCCESS) {
+ return STS_ERROR;
}
- /*
- * Iterate through the list of adapters as registry settings are
- * keyed on the adapter name (GUID).
- */
- if (ret == ERROR_SUCCESS) {
- IP_ADAPTER_INFO *curr = adapterP;
- while (curr != NULL) {
- char key[MAX_STR_LEN];
-
- sprintf(key,
-
"SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces\\%s",
- curr->AdapterName);
-
- ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
- key,
- 0,
- KEY_READ,
- (PHKEY)&hKey);
- if (ret == ERROR_SUCCESS) {
- DWORD enableDhcp = 0;
-
- /*
- * Is DHCP enabled on this interface
- */
- dwLen = sizeof(enableDhcp);
- ret = RegQueryValueEx(hKey, "EnableDhcp", NULL, &ulType,
- (LPBYTE)&enableDhcp, &dwLen);
-
- /*
- * If we don't have the suffix list when get the Domain
- * or DhcpDomain. If DHCP is enabled then Domain overides
- * DhcpDomain
- */
- if (!gotSearchList) {
- result[0] = '\0';
- dwLen = sizeof(result);
- ret = RegQueryValueEx(hKey, "Domain", NULL, &ulType,
- (LPBYTE)&result, &dwLen);
- if (((ret != ERROR_SUCCESS) || (strlen(result) == 0))
&&
- enableDhcp) {
- dwLen = sizeof(result);
- ret = RegQueryValueEx(hKey, "DhcpDomain", NULL,
&ulType,
- (LPBYTE)&result, &dwLen);
- }
- if (ret == ERROR_SUCCESS) {
- assert(ulType == REG_SZ);
- strappend(sl, result);
- }
- }
-
- /*
- * Get DNS servers based on NameServer or DhcpNameServer
- * registry setting. If NameServer is set then it overrides
- * DhcpNameServer (even if DHCP is enabled).
- */
- result[0] = '\0';
+ adapter = adapters;
+ while (adapter != NULL) {
+ // Only load config from enabled adapters.
+ if (adapter->OperStatus == IfOperStatusUp) {
+ dnsServer = adapter->FirstDnsServerAddress;
+ while (dnsServer != NULL) {
+ address = dnsServer->Address.lpSockaddr;
dwLen = sizeof(result);
- ret = RegQueryValueEx(hKey, "NameServer", NULL, &ulType,
- (LPBYTE)&result, &dwLen);
- if (((ret != ERROR_SUCCESS) || (strlen(result) == 0)) &&
- enableDhcp) {
- dwLen = sizeof(result);
- ret = RegQueryValueEx(hKey, "DhcpNameServer", NULL,
&ulType,
- (LPBYTE)&result, &dwLen);
- }
- if (ret == ERROR_SUCCESS) {
- assert(ulType == REG_SZ);
+ ret = WSAAddressToStringA(dnsServer->Address.lpSockaddr,
+ dnsServer->Address.iSockaddrLength, NULL,
+ result, &dwLen);
+ if (ret == 0) {
strappend(ns, result);
}
- /*
- * Finished with this registry key
- */
- RegCloseKey(hKey);
+ dnsServer = dnsServer->Next;
}
- /*
- * Onto the next adapeter
- */
- curr = curr->Next;
+ // Add connection-specific search domains in addition to
global one.
+ suffix = adapter->FirstDnsSuffix;
+ while (suffix != NULL) {
+ ret = WideCharToMultiByte(CP_UTF8, 0, suffix->String, -1,
+ result, sizeof(result), NULL, NULL);
+ if (ret != 0) {
+ strappend(sl, result);
+ }
+
+ suffix = suffix->Next;
+ }
}
- }
- /*
- * Free the adpater structure
- */
- if (adapterP) {
- free(adapterP);
+ adapter = adapter->Next;
}
+ free(adapters);
+
return STS_SL_FOUND & STS_NS_FOUND;
}
@@ -260,7 +189,7 @@
Java_sun_net_dns_ResolverConfigurationImpl_loadDNSconfig0(JNIEnv *env,
jclass cl
searchlist[0] = '\0';
nameservers[0] = '\0';
- if (loadConfig(searchlist, nameservers) != STS_ERROR) {
+ if (loadConfig(env, searchlist, nameservers) != STS_ERROR) {
/*
* Populate static fields in sun.net.DefaultResolverConfiguration
On Thu, Dec 5, 2019 at 12:56 AM Aleks Efimov <aleksej.efimov at oracle.com>
wrote:
> Hi Anuraag,
>
> I've run your latest patch via our CI system and the results are good
>
> One comment about the code changes:
> I'm not sure that we need to pre-calculate the array list size since we
> can get the same name server address multiple times and we will ignore the
> duplicates later ('l.contains(s)' check). The default ArrayList constructor
> (10 elements size) and the 'ArrayList::trimToSize' could be used.
>
> Or maybe combine both approaches (pre-calculate + resize):
> Use 'StringTokenizer::countTokens' (replacement for
> 'allocateListForDelimitedString' method that can be deleted) for initial
> size calculation and after processing tokens call 'ArrayList::trimToSize'.
> For cases with no duplicates (more frequent case) it should be cheap.
>
> Best Regards,
> Aleksei
>
>
> On 03/12/2019 06:09, Anuraag Agrawal wrote:
>
> Hi Aleksei,
>
> Thanks a lot for running the CI and even looking into the failures! I had
> only intended to update comments in the second patch and admittedly didn't
> actually run the code, obviously that wasn't a good idea... Here's an
> updated patch with the call to loadDNSConfig0() restored.
>
> Inline patch follows
>
> diff --git
> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> index 2250b3158e..03c57da415 100644
> ---
> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> +++
> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
> @@ -25,9 +25,10 @@
>
> package sun.net.dns;
>
> +import java.util.ArrayList;
> import java.util.List;
> -import java.util.LinkedList;
> import java.util.StringTokenizer;
> +import java.util.concurrent.TimeUnit;
>
> /*
> * An implementation of sun.net.ResolverConfiguration for Windows.
> @@ -50,30 +51,69 @@ public class ResolverConfigurationImpl
>
> // Cache timeout (120 seconds) - should be converted into property
> // or configured as preference in the future.
> - private static final int TIMEOUT = 120000;
> + private static final long TIMEOUT_NANOS =
> TimeUnit.SECONDS.toNanos(120);
>
> // DNS suffix list and name servers populated by native method
> private static String os_searchlist;
> private static String os_nameservers;
>
> // Cached lists
> - private static LinkedList<String> searchlist;
> - private static LinkedList<String> nameservers;
> + private static ArrayList<String> searchlist;
> + private static ArrayList<String> nameservers;
>
> - // Parse string that consists of token delimited by space or commas
> - // and return LinkedHashMap
> - private LinkedList<String> stringToList(String str) {
> - LinkedList<String> ll = new LinkedList<>();
> + // Parse string that consists of token delimited by space
> + // and return ArrayList. Refer to ResolverConfigurationImpl.c and
> + // strappend to see how the string is created.
> + private ArrayList<String> stringToList(String str) {
> + ArrayList<String> l = allocateListForDelimitedString(str);
>
> - // comma and space are valid delimiters
> - StringTokenizer st = new StringTokenizer(str, ", ");
> + // String is delimited by space.
> + StringTokenizer st = new StringTokenizer(str, " ");
> while (st.hasMoreTokens()) {
> String s = st.nextToken();
> - if (!ll.contains(s)) {
> - ll.add(s);
> + if (!l.contains(s)) {
> + l.add(s);
> }
> }
> - return ll;
> + return l;
> + }
> +
> + // Parse string that consists of token delimited by space
> + // and return ArrayList. Refer to ResolverConfigurationImpl.c and
> + // strappend to see how the string is created.
> + // In addition to splitting the string, converts IPv6 addresses to
> + // BSD-style.
> + private ArrayList<String> addressesToList(String str) {
> + ArrayList<String> l = allocateListForDelimitedString(str);
> +
> + // String is delimited by space
> + StringTokenizer st = new StringTokenizer(str, " ");
> + while (st.hasMoreTokens()) {
> + String s = st.nextToken();
> + if (!s.isEmpty()) {
> + if (s.indexOf(':') >= 0 && s.charAt(0) != '[') {
> + // Not BSD style
> + s = '[' + s + ']';
> + }
> + if (!l.contains(s)) {
> + l.add(s);
> + }
> + }
> + }
> + return l;
> + }
> +
> + private ArrayList<String> allocateListForDelimitedString(String str) {
> + int num = 0;
> + for (int i = 0; i < str.length(); i++) {
> + char c = str.charAt(i);
> + // String is space separated list of items
> + if (c == ' ') {
> + num++;
> + }
> + }
> + // Actual num is number of delimiters + 1
> + return new ArrayList<String>(num + 1);
> }
>
> // Load DNS configuration from OS
> @@ -81,28 +121,34 @@ public class ResolverConfigurationImpl
> private void loadConfig() {
> assert Thread.holdsLock(lock);
>
> - // if address have changed then DNS probably changed as well;
> - // otherwise check if cached settings have expired.
> - //
> + // A change in the network address of the machine usually
> indicates
> + // a change in DNS configuration too so we always refresh the
> config
> + // after such a change.
> if (changed) {
> changed = false;
> } else {
> + // Otherwise we refresh if TIMEOUT_NANOS has passed since last
> + // load.
> if (lastRefresh >= 0) {
> - long currTime = System.currentTimeMillis();
> - if ((currTime - lastRefresh) < TIMEOUT) {
> + long currTime = System.nanoTime();
> + if ((currTime - lastRefresh) < TIMEOUT_NANOS) {
> return;
> }
> }
> }
>
> - // load DNS configuration, update timestamp, create
> - // new HashMaps from the loaded configuration
> - //
> + // Native code that uses Windows API to find out the DNS server
> + // addresses and search suffixes. It builds a space-delimited
> string
> + // of nameservers and domain suffixes and sets them to the static
> + // os_nameservers and os_searchlist. We then split these into Java
> + // Lists here.
> loadDNSconfig0();
>
> - lastRefresh = System.currentTimeMillis();
> + // Record the time of update and refresh the lists of addresses /
> + // domain suffixes.
> + lastRefresh = System.nanoTime();
> searchlist = stringToList(os_searchlist);
> - nameservers = stringToList(os_nameservers);
> + nameservers = addressesToList(os_nameservers);
> os_searchlist = null; // can be GC'ed
> os_nameservers = null;
> }
> diff --git a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> index f2368bafcb..297a1561ef 100644
> --- a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> +++ b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
> @@ -73,8 +73,8 @@ const int MAX_TRIES = 3;
> * for each adapter on the system. Returned in *adapters.
> * Buffer is malloc'd and must be freed (unless error returned)
> */
> -static int getAdapters (JNIEnv *env, IP_ADAPTER_ADDRESSES **adapters) {
> - DWORD ret, flags;
> +int getAdapters (JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES **adapters)
> {
> + DWORD ret;
> IP_ADAPTER_ADDRESSES *adapterInfo;
> ULONG len;
> int try;
> @@ -87,9 +87,6 @@ static int getAdapters (JNIEnv *env,
> IP_ADAPTER_ADDRESSES **adapters) {
> }
>
> len = BUFF_SIZE;
> - flags = GAA_FLAG_SKIP_DNS_SERVER;
> - flags |= GAA_FLAG_SKIP_MULTICAST;
> - flags |= GAA_FLAG_INCLUDE_PREFIX;
> ret = GetAdaptersAddresses(AF_UNSPEC, flags, NULL, adapterInfo, &len);
>
> for (try = 0; ret == ERROR_BUFFER_OVERFLOW && try < MAX_TRIES; ++try)
> {
> @@ -240,7 +237,7 @@ static int ipinflen = 2048;
> */
> int getAllInterfacesAndAddresses (JNIEnv *env, netif **netifPP)
> {
> - DWORD ret;
> + DWORD ret, flags;
> MIB_IPADDRTABLE *tableP;
> IP_ADAPTER_ADDRESSES *ptr, *adapters=NULL;
> ULONG len=ipinflen, count=0;
> @@ -296,7 +293,11 @@ int getAllInterfacesAndAddresses (JNIEnv *env, netif
> **netifPP)
> }
> }
> free(tableP);
> - ret = getAdapters (env, &adapters);
> +
> + flags = GAA_FLAG_SKIP_DNS_SERVER;
> + flags |= GAA_FLAG_SKIP_MULTICAST;
> + flags |= GAA_FLAG_INCLUDE_PREFIX;
> + ret = getAdapters (env, flags, &adapters);
> if (ret != ERROR_SUCCESS) {
> goto err;
> }
> diff --git
> a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> index 13b28044a5..83100aa9ad 100644
> --- a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> +++ b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
> @@ -30,6 +30,7 @@
> #include <iprtrmib.h>
> #include <time.h>
> #include <assert.h>
> +#include <winsock2.h>
> #include <iphlpapi.h>
>
> #include "jni_util.h"
> @@ -48,6 +49,8 @@
> static jfieldID searchlistID;
> static jfieldID nameserversID;
>
> +extern int getAdapters(JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES
> **adapters);
> +
> /*
> * Utility routine to append s2 to s1 with a space delimiter.
> * strappend(s1="abc", "def") => "abc def"
> @@ -72,29 +75,19 @@ void strappend(char *s1, char *s2) {
> }
>
> /*
> - * Windows 2000/XP
> - *
> - * Use registry approach based on settings described in Appendix C
> - * of "Microsoft Windows 2000 TCP/IP Implementation Details".
> - *
> - * DNS suffix list is obtained from SearchList registry setting. If
> - * this is not specified we compile suffix list based on the
> - * per-connection domain suffix.
> - *
> - * DNS name servers and domain settings are on a per-connection
> - * basic. We therefore enumerate the network adapters to get the
> - * names of each adapter and then query the corresponding registry
> - * settings to obtain NameServer/DhcpNameServer and Domain/DhcpDomain.
> + * Use DNS server addresses returned by GetAdaptersAddresses for
> currently
> + * active interfaces.
> */
> -static int loadConfig(char *sl, char *ns) {
> - IP_ADAPTER_INFO *adapterP;
> - ULONG size;
> - DWORD ret;
> +static int loadConfig(JNIEnv *env, char *sl, char *ns) {
> + IP_ADAPTER_ADDRESSES *adapters, *adapter;
> + IP_ADAPTER_DNS_SERVER_ADDRESS *dnsServer;
> + SOCKADDR *address;
> + IP_ADAPTER_DNS_SUFFIX *suffix;
> + DWORD ret, flags;
> DWORD dwLen;
> ULONG ulType;
> char result[MAX_STR_LEN];
> HANDLE hKey;
> - int gotSearchList = 0;
>
> /*
> * First see if there is a global suffix list specified.
> @@ -112,122 +105,58 @@ static int loadConfig(char *sl, char *ns) {
> assert(ulType == REG_SZ);
> if (strlen(result) > 0) {
> strappend(sl, result);
> - gotSearchList = 1;
> }
> }
> RegCloseKey(hKey);
> }
>
> - /*
> - * Ask the IP Helper library to enumerate the adapters
> - */
> - size = sizeof(IP_ADAPTER_INFO);
> - adapterP = (IP_ADAPTER_INFO *)malloc(size);
> - if (adapterP == NULL) {
> - return STS_ERROR;
> - }
> - ret = GetAdaptersInfo(adapterP, &size);
> - if (ret == ERROR_BUFFER_OVERFLOW) {
> - IP_ADAPTER_INFO *newAdapterP = (IP_ADAPTER_INFO
> *)realloc(adapterP, size);
> - if (newAdapterP == NULL) {
> - free(adapterP);
> - return STS_ERROR;
> - }
> - adapterP = newAdapterP;
>
> - ret = GetAdaptersInfo(adapterP, &size);
> + // We only need DNS server addresses so skip everything else.
> + flags = GAA_FLAG_SKIP_UNICAST;
> + flags |= GAA_FLAG_SKIP_ANYCAST;
> + flags |= GAA_FLAG_SKIP_MULTICAST;
> + flags |= GAA_FLAG_SKIP_FRIENDLY_NAME;
> + ret = getAdapters(env, flags, &adapters);
> + if (ret != ERROR_SUCCESS) {
> + return STS_ERROR;
> }
>
> - /*
> - * Iterate through the list of adapters as registry settings are
> - * keyed on the adapter name (GUID).
> - */
> - if (ret == ERROR_SUCCESS) {
> - IP_ADAPTER_INFO *curr = adapterP;
> - while (curr != NULL) {
> - char key[MAX_STR_LEN];
> -
> - sprintf(key,
> -
> "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces\\%s",
> - curr->AdapterName);
> -
> - ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
> - key,
> - 0,
> - KEY_READ,
> - (PHKEY)&hKey);
> - if (ret == ERROR_SUCCESS) {
> - DWORD enableDhcp = 0;
> -
> - /*
> - * Is DHCP enabled on this interface
> - */
> - dwLen = sizeof(enableDhcp);
> - ret = RegQueryValueEx(hKey, "EnableDhcp", NULL, &ulType,
> - (LPBYTE)&enableDhcp, &dwLen);
> -
> - /*
> - * If we don't have the suffix list when get the Domain
> - * or DhcpDomain. If DHCP is enabled then Domain overides
> - * DhcpDomain
> - */
> - if (!gotSearchList) {
> - result[0] = '\0';
> - dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "Domain", NULL, &ulType,
> - (LPBYTE)&result, &dwLen);
> - if (((ret != ERROR_SUCCESS) || (strlen(result) == 0))
> &&
> - enableDhcp) {
> - dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "DhcpDomain", NULL,
> &ulType,
> - (LPBYTE)&result, &dwLen);
> - }
> - if (ret == ERROR_SUCCESS) {
> - assert(ulType == REG_SZ);
> - strappend(sl, result);
> - }
> - }
> -
> - /*
> - * Get DNS servers based on NameServer or DhcpNameServer
> - * registry setting. If NameServer is set then it
> overrides
> - * DhcpNameServer (even if DHCP is enabled).
> - */
> - result[0] = '\0';
> + adapter = adapters;
> + while (adapter != NULL) {
> + // Only load config from enabled adapters.
> + if (adapter->OperStatus == IfOperStatusUp) {
> + dnsServer = adapter->FirstDnsServerAddress;
> + while (dnsServer != NULL) {
> + address = dnsServer->Address.lpSockaddr;
> dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "NameServer", NULL, &ulType,
> - (LPBYTE)&result, &dwLen);
> - if (((ret != ERROR_SUCCESS) || (strlen(result) == 0)) &&
> - enableDhcp) {
> - dwLen = sizeof(result);
> - ret = RegQueryValueEx(hKey, "DhcpNameServer", NULL,
> &ulType,
> - (LPBYTE)&result, &dwLen);
> - }
> - if (ret == ERROR_SUCCESS) {
> - assert(ulType == REG_SZ);
> + ret = WSAAddressToStringA(dnsServer->Address.lpSockaddr,
> + dnsServer->Address.iSockaddrLength, NULL,
> + result, &dwLen);
> + if (ret == 0) {
> strappend(ns, result);
> }
>
> - /*
> - * Finished with this registry key
> - */
> - RegCloseKey(hKey);
> + dnsServer = dnsServer->Next;
> }
>
> - /*
> - * Onto the next adapeter
> - */
> - curr = curr->Next;
> + // Add connection-specific search domains in addition to
> global one.
> + suffix = adapter->FirstDnsSuffix;
> + while (suffix != NULL) {
> + ret = WideCharToMultiByte(CP_UTF8, 0, suffix->String, -1,
> + result, sizeof(result), NULL, NULL);
> + if (ret != 0) {
> + strappend(sl, result);
> + }
> +
> + suffix = suffix->Next;
> + }
> }
> - }
>
> - /*
> - * Free the adpater structure
> - */
> - if (adapterP) {
> - free(adapterP);
> + adapter = adapter->Next;
> }
>
> + free(adapters);
> +
> return STS_SL_FOUND & STS_NS_FOUND;
> }
>
> @@ -260,7 +189,7 @@
> Java_sun_net_dns_ResolverConfigurationImpl_loadDNSconfig0(JNIEnv *env,
> jclass cl
> searchlist[0] = '\0';
> nameservers[0] = '\0';
>
> - if (loadConfig(searchlist, nameservers) != STS_ERROR) {
> + if (loadConfig(env, searchlist, nameservers) != STS_ERROR) {
>
> /*
> * Populate static fields in sun.net.DefaultResolverConfiguration
>
> On Tue, Dec 3, 2019 at 1:24 AM Aleks Efimov <aleksej.efimov at oracle.com>
> wrote:
>
>> Hey Anuraag,
>>
>> I've looked at the failures and I believe that your second patch
>> accidentally removed 'loadDNSconfig0()' native call.
>> Putting it back to
>> src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java:145
>> resolves all these failures.
>>
>> -Aleksei
>>
>>
>> On 02/12/2019 13:04, Aleks Efimov wrote:
>>
>> Hi Anuraag,
>>
>> I've submited your patch to our CI system and I'm observing a bunch of
>> NPE failures with such stack trace:
>> java.lang.NullPointerException
>> at
>> java.base/sun.net.dns.ResolverConfigurationImpl.allocateListForDelimitedString(ResolverConfigurationImpl.java:108)
>> at
>> java.base/sun.net.dns.ResolverConfigurationImpl.stringToList(ResolverConfigurationImpl.java:68)
>> at
>> java.base/sun.net.dns.ResolverConfigurationImpl.loadConfig(ResolverConfigurationImpl.java:149)
>> at
>> java.base/sun.net.dns.ResolverConfigurationImpl.nameservers(ResolverConfigurationImpl.java:172)
>> at
>> jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.platformServersAvailable(DnsContextFactory.java:94)
>> at
>> jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.platformServersUsed(DnsContextFactory.java:171)
>> at
>> jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.getContext(DnsContextFactory.java:83)
>> at
>> jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.urlToContext(DnsContextFactory.java:120)
>> at
>> jdk.naming.dns/com.sun.jndi.dns.DnsContextFactory.getInitialContext(DnsContextFactory.java:64)
>> at
>> java.naming/javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:730)
>> at
>> java.naming/javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:305)
>> at
>> java.naming/javax.naming.InitialContext.init(InitialContext.java:236)
>> at
>> java.naming/javax.naming.InitialContext.<init>(InitialContext.java:208)
>> at
>> java.naming/javax.naming.directory.InitialDirContext.<init>(InitialDirContext.java:130)
>> at LookupWithAnyAttrProp.runTest(LookupWithAnyAttrProp.java:57)
>> at TestBase.launch(TestBase.java:82)
>> at TestBase.run(TestBase.java:50)
>> at LookupWithAnyAttrProp.main(LookupWithAnyAttrProp.java:43)
>> at
>> java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native
>> Method)
>> at
>> java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
>> at
>> java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>> at java.base/java.lang.reflect.Method.invoke(Method.java:564)
>> at
>> com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
>> at java.base/java.lang.Thread.run(Thread.java:832)
>>
>> Few examples of failing tests:
>> test/jdk/com/sun/jndi/dns/FedTests/ListSubInterior.java (and others in
>> the same folder)
>> test/jdk/com/sun/jndi/dns/FactoryTests/LookupWithAnyAttrProp.java (and
>> others in the same folder)
>>
>> Test platform is: Windows Server 2012 R2 6.3
>>
>> With Best Regards,
>> Aleksei
>>
>> On 25/11/2019 05:09, Anuraag Agrawal wrote:
>>
>> Hi Bernd,
>>
>> Thanks for the look and suggestion. I have updated those comments, as
>> well as added several more to explain the native code aspects better which
>> I hope helps future readers of the code. Hope it looks better now.
>>
>> Inline patch follows
>>
>> diff --git
>> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
>> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
>> index 2250b3158e..18996f0ee0 100644
>> ---
>> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
>> +++
>> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
>> @@ -25,9 +25,10 @@
>>
>> package sun.net.dns;
>>
>> +import java.util.ArrayList;
>> import java.util.List;
>> -import java.util.LinkedList;
>> import java.util.StringTokenizer;
>> +import java.util.concurrent.TimeUnit;
>>
>> /*
>> * An implementation of sun.net.ResolverConfiguration for Windows.
>> @@ -50,30 +51,69 @@ public class ResolverConfigurationImpl
>>
>> // Cache timeout (120 seconds) - should be converted into property
>> // or configured as preference in the future.
>> - private static final int TIMEOUT = 120000;
>> + private static final long TIMEOUT_NANOS =
>> TimeUnit.SECONDS.toNanos(120);
>>
>> // DNS suffix list and name servers populated by native method
>> private static String os_searchlist;
>> private static String os_nameservers;
>>
>> // Cached lists
>> - private static LinkedList<String> searchlist;
>> - private static LinkedList<String> nameservers;
>> + private static ArrayList<String> searchlist;
>> + private static ArrayList<String> nameservers;
>>
>> - // Parse string that consists of token delimited by space or commas
>> - // and return LinkedHashMap
>> - private LinkedList<String> stringToList(String str) {
>> - LinkedList<String> ll = new LinkedList<>();
>> + // Parse string that consists of token delimited by space
>> + // and return ArrayList. Refer to ResolverConfigurationImpl.c and
>> + // strappend to see how the string is created.
>> + private ArrayList<String> stringToList(String str) {
>> + ArrayList<String> l = allocateListForDelimitedString(str);
>>
>> - // comma and space are valid delimiters
>> - StringTokenizer st = new StringTokenizer(str, ", ");
>> + // String is delimited by space.
>> + StringTokenizer st = new StringTokenizer(str, " ");
>> while (st.hasMoreTokens()) {
>> String s = st.nextToken();
>> - if (!ll.contains(s)) {
>> - ll.add(s);
>> + if (!l.contains(s)) {
>> + l.add(s);
>> }
>> }
>> - return ll;
>> + return l;
>> + }
>> +
>> + // Parse string that consists of token delimited by space
>> + // and return ArrayList. Refer to ResolverConfigurationImpl.c and
>> + // strappend to see how the string is created.
>> + // In addition to splitting the string, converts IPv6 addresses to
>> + // BSD-style.
>> + private ArrayList<String> addressesToList(String str) {
>> + ArrayList<String> l = allocateListForDelimitedString(str);
>> +
>> + // String is delimited by space
>> + StringTokenizer st = new StringTokenizer(str, " ");
>> + while (st.hasMoreTokens()) {
>> + String s = st.nextToken();
>> + if (!s.isEmpty()) {
>> + if (s.indexOf(':') >= 0 && s.charAt(0) != '[') {
>> + // Not BSD style
>> + s = '[' + s + ']';
>> + }
>> + if (!l.contains(s)) {
>> + l.add(s);
>> + }
>> + }
>> + }
>> + return l;
>> + }
>> +
>> + private ArrayList<String> allocateListForDelimitedString(String str)
>> {
>> + int num = 0;
>> + for (int i = 0; i < str.length(); i++) {
>> + char c = str.charAt(i);
>> + // String is space separated list of items
>> + if (c == ' ') {
>> + num++;
>> + }
>> + }
>> + // Actual num is number of delimiters + 1
>> + return new ArrayList<String>(num + 1);
>> }
>>
>> // Load DNS configuration from OS
>> @@ -81,28 +121,33 @@ public class ResolverConfigurationImpl
>> private void loadConfig() {
>> assert Thread.holdsLock(lock);
>>
>> - // if address have changed then DNS probably changed as well;
>> - // otherwise check if cached settings have expired.
>> - //
>> + // A change in the network address of the machine usually
>> indicates
>> + // a change in DNS configuration too so we always refresh the
>> config
>> + // after such a change.
>> if (changed) {
>> changed = false;
>> } else {
>> + // Otherwise we refresh if TIMEOUT_NANOS has passed since
>> last
>> + // load.
>> if (lastRefresh >= 0) {
>> - long currTime = System.currentTimeMillis();
>> - if ((currTime - lastRefresh) < TIMEOUT) {
>> + long currTime = System.nanoTime();
>> + if ((currTime - lastRefresh) < TIMEOUT_NANOS) {
>> return;
>> }
>> }
>> }
>>
>> - // load DNS configuration, update timestamp, create
>> - // new HashMaps from the loaded configuration
>> - //
>> - loadDNSconfig0();
>> + // Native code that uses Windows API to find out the DNS server
>> + // addresses and search suffixes. It builds a space-delimited
>> string
>> + // of nameservers and domain suffixes and sets them to the static
>> + // os_nameservers and os_searchlist. We then split these into
>> Java
>> + // Lists here.
>>
>> - lastRefresh = System.currentTimeMillis();
>> + // Record the time of update and refresh the lists of addresses /
>> + // domain suffixes.
>> + lastRefresh = System.nanoTime();
>> searchlist = stringToList(os_searchlist);
>> - nameservers = stringToList(os_nameservers);
>> + nameservers = addressesToList(os_nameservers);
>> os_searchlist = null; // can be GC'ed
>> os_nameservers = null;
>> }
>> diff --git a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
>> b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
>> index f2368bafcb..297a1561ef 100644
>> --- a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
>> +++ b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
>> @@ -73,8 +73,8 @@ const int MAX_TRIES = 3;
>> * for each adapter on the system. Returned in *adapters.
>> * Buffer is malloc'd and must be freed (unless error returned)
>> */
>> -static int getAdapters (JNIEnv *env, IP_ADAPTER_ADDRESSES **adapters) {
>> - DWORD ret, flags;
>> +int getAdapters (JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES
>> **adapters) {
>> + DWORD ret;
>> IP_ADAPTER_ADDRESSES *adapterInfo;
>> ULONG len;
>> int try;
>> @@ -87,9 +87,6 @@ static int getAdapters (JNIEnv *env,
>> IP_ADAPTER_ADDRESSES **adapters) {
>> }
>>
>> len = BUFF_SIZE;
>> - flags = GAA_FLAG_SKIP_DNS_SERVER;
>> - flags |= GAA_FLAG_SKIP_MULTICAST;
>> - flags |= GAA_FLAG_INCLUDE_PREFIX;
>> ret = GetAdaptersAddresses(AF_UNSPEC, flags, NULL, adapterInfo,
>> &len);
>>
>> for (try = 0; ret == ERROR_BUFFER_OVERFLOW && try < MAX_TRIES;
>> ++try) {
>> @@ -240,7 +237,7 @@ static int ipinflen = 2048;
>> */
>> int getAllInterfacesAndAddresses (JNIEnv *env, netif **netifPP)
>> {
>> - DWORD ret;
>> + DWORD ret, flags;
>> MIB_IPADDRTABLE *tableP;
>> IP_ADAPTER_ADDRESSES *ptr, *adapters=NULL;
>> ULONG len=ipinflen, count=0;
>> @@ -296,7 +293,11 @@ int getAllInterfacesAndAddresses (JNIEnv *env, netif
>> **netifPP)
>> }
>> }
>> free(tableP);
>> - ret = getAdapters (env, &adapters);
>> +
>> + flags = GAA_FLAG_SKIP_DNS_SERVER;
>> + flags |= GAA_FLAG_SKIP_MULTICAST;
>> + flags |= GAA_FLAG_INCLUDE_PREFIX;
>> + ret = getAdapters (env, flags, &adapters);
>> if (ret != ERROR_SUCCESS) {
>> goto err;
>> }
>> diff --git
>> a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
>> b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
>> index 13b28044a5..83100aa9ad 100644
>> --- a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
>> +++ b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
>> @@ -30,6 +30,7 @@
>> #include <iprtrmib.h>
>> #include <time.h>
>> #include <assert.h>
>> +#include <winsock2.h>
>> #include <iphlpapi.h>
>>
>> #include "jni_util.h"
>> @@ -48,6 +49,8 @@
>> static jfieldID searchlistID;
>> static jfieldID nameserversID;
>>
>> +extern int getAdapters(JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES
>> **adapters);
>> +
>> /*
>> * Utility routine to append s2 to s1 with a space delimiter.
>> * strappend(s1="abc", "def") => "abc def"
>> @@ -72,29 +75,19 @@ void strappend(char *s1, char *s2) {
>> }
>>
>> /*
>> - * Windows 2000/XP
>> - *
>> - * Use registry approach based on settings described in Appendix C
>> - * of "Microsoft Windows 2000 TCP/IP Implementation Details".
>> - *
>> - * DNS suffix list is obtained from SearchList registry setting. If
>> - * this is not specified we compile suffix list based on the
>> - * per-connection domain suffix.
>> - *
>> - * DNS name servers and domain settings are on a per-connection
>> - * basic. We therefore enumerate the network adapters to get the
>> - * names of each adapter and then query the corresponding registry
>> - * settings to obtain NameServer/DhcpNameServer and Domain/DhcpDomain.
>> + * Use DNS server addresses returned by GetAdaptersAddresses for
>> currently
>> + * active interfaces.
>> */
>> -static int loadConfig(char *sl, char *ns) {
>> - IP_ADAPTER_INFO *adapterP;
>> - ULONG size;
>> - DWORD ret;
>> +static int loadConfig(JNIEnv *env, char *sl, char *ns) {
>> + IP_ADAPTER_ADDRESSES *adapters, *adapter;
>> + IP_ADAPTER_DNS_SERVER_ADDRESS *dnsServer;
>> + SOCKADDR *address;
>> + IP_ADAPTER_DNS_SUFFIX *suffix;
>> + DWORD ret, flags;
>> DWORD dwLen;
>> ULONG ulType;
>> char result[MAX_STR_LEN];
>> HANDLE hKey;
>> - int gotSearchList = 0;
>>
>> /*
>> * First see if there is a global suffix list specified.
>> @@ -112,122 +105,58 @@ static int loadConfig(char *sl, char *ns) {
>> assert(ulType == REG_SZ);
>> if (strlen(result) > 0) {
>> strappend(sl, result);
>> - gotSearchList = 1;
>> }
>> }
>> RegCloseKey(hKey);
>> }
>>
>> - /*
>> - * Ask the IP Helper library to enumerate the adapters
>> - */
>> - size = sizeof(IP_ADAPTER_INFO);
>> - adapterP = (IP_ADAPTER_INFO *)malloc(size);
>> - if (adapterP == NULL) {
>> - return STS_ERROR;
>> - }
>> - ret = GetAdaptersInfo(adapterP, &size);
>> - if (ret == ERROR_BUFFER_OVERFLOW) {
>> - IP_ADAPTER_INFO *newAdapterP = (IP_ADAPTER_INFO
>> *)realloc(adapterP, size);
>> - if (newAdapterP == NULL) {
>> - free(adapterP);
>> - return STS_ERROR;
>> - }
>> - adapterP = newAdapterP;
>>
>> - ret = GetAdaptersInfo(adapterP, &size);
>> + // We only need DNS server addresses so skip everything else.
>> + flags = GAA_FLAG_SKIP_UNICAST;
>> + flags |= GAA_FLAG_SKIP_ANYCAST;
>> + flags |= GAA_FLAG_SKIP_MULTICAST;
>> + flags |= GAA_FLAG_SKIP_FRIENDLY_NAME;
>> + ret = getAdapters(env, flags, &adapters);
>> + if (ret != ERROR_SUCCESS) {
>> + return STS_ERROR;
>> }
>>
>> - /*
>> - * Iterate through the list of adapters as registry settings are
>> - * keyed on the adapter name (GUID).
>> - */
>> - if (ret == ERROR_SUCCESS) {
>> - IP_ADAPTER_INFO *curr = adapterP;
>> - while (curr != NULL) {
>> - char key[MAX_STR_LEN];
>> -
>> - sprintf(key,
>> -
>> "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces\\%s",
>> - curr->AdapterName);
>> -
>> - ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
>> - key,
>> - 0,
>> - KEY_READ,
>> - (PHKEY)&hKey);
>> - if (ret == ERROR_SUCCESS) {
>> - DWORD enableDhcp = 0;
>> -
>> - /*
>> - * Is DHCP enabled on this interface
>> - */
>> - dwLen = sizeof(enableDhcp);
>> - ret = RegQueryValueEx(hKey, "EnableDhcp", NULL, &ulType,
>> - (LPBYTE)&enableDhcp, &dwLen);
>> -
>> - /*
>> - * If we don't have the suffix list when get the Domain
>> - * or DhcpDomain. If DHCP is enabled then Domain overides
>> - * DhcpDomain
>> - */
>> - if (!gotSearchList) {
>> - result[0] = '\0';
>> - dwLen = sizeof(result);
>> - ret = RegQueryValueEx(hKey, "Domain", NULL, &ulType,
>> - (LPBYTE)&result, &dwLen);
>> - if (((ret != ERROR_SUCCESS) || (strlen(result) ==
>> 0)) &&
>> - enableDhcp) {
>> - dwLen = sizeof(result);
>> - ret = RegQueryValueEx(hKey, "DhcpDomain", NULL,
>> &ulType,
>> - (LPBYTE)&result, &dwLen);
>> - }
>> - if (ret == ERROR_SUCCESS) {
>> - assert(ulType == REG_SZ);
>> - strappend(sl, result);
>> - }
>> - }
>> -
>> - /*
>> - * Get DNS servers based on NameServer or DhcpNameServer
>> - * registry setting. If NameServer is set then it
>> overrides
>> - * DhcpNameServer (even if DHCP is enabled).
>> - */
>> - result[0] = '\0';
>> + adapter = adapters;
>> + while (adapter != NULL) {
>> + // Only load config from enabled adapters.
>> + if (adapter->OperStatus == IfOperStatusUp) {
>> + dnsServer = adapter->FirstDnsServerAddress;
>> + while (dnsServer != NULL) {
>> + address = dnsServer->Address.lpSockaddr;
>> dwLen = sizeof(result);
>> - ret = RegQueryValueEx(hKey, "NameServer", NULL, &ulType,
>> - (LPBYTE)&result, &dwLen);
>> - if (((ret != ERROR_SUCCESS) || (strlen(result) == 0)) &&
>> - enableDhcp) {
>> - dwLen = sizeof(result);
>> - ret = RegQueryValueEx(hKey, "DhcpNameServer", NULL,
>> &ulType,
>> - (LPBYTE)&result, &dwLen);
>> - }
>> - if (ret == ERROR_SUCCESS) {
>> - assert(ulType == REG_SZ);
>> + ret = WSAAddressToStringA(dnsServer->Address.lpSockaddr,
>> + dnsServer->Address.iSockaddrLength, NULL,
>> + result, &dwLen);
>> + if (ret == 0) {
>> strappend(ns, result);
>> }
>>
>> - /*
>> - * Finished with this registry key
>> - */
>> - RegCloseKey(hKey);
>> + dnsServer = dnsServer->Next;
>> }
>>
>> - /*
>> - * Onto the next adapeter
>> - */
>> - curr = curr->Next;
>> + // Add connection-specific search domains in addition to
>> global one.
>> + suffix = adapter->FirstDnsSuffix;
>> + while (suffix != NULL) {
>> + ret = WideCharToMultiByte(CP_UTF8, 0, suffix->String,
>> -1,
>> + result, sizeof(result), NULL, NULL);
>> + if (ret != 0) {
>> + strappend(sl, result);
>> + }
>> +
>> + suffix = suffix->Next;
>> + }
>> }
>> - }
>>
>> - /*
>> - * Free the adpater structure
>> - */
>> - if (adapterP) {
>> - free(adapterP);
>> + adapter = adapter->Next;
>> }
>>
>> + free(adapters);
>> +
>> return STS_SL_FOUND & STS_NS_FOUND;
>> }
>>
>> @@ -260,7 +189,7 @@
>> Java_sun_net_dns_ResolverConfigurationImpl_loadDNSconfig0(JNIEnv *env,
>> jclass cl
>> searchlist[0] = '\0';
>> nameservers[0] = '\0';
>>
>> - if (loadConfig(searchlist, nameservers) != STS_ERROR) {
>> + if (loadConfig(env, searchlist, nameservers) != STS_ERROR) {
>>
>> /*
>> * Populate static fields in sun.net.DefaultResolverConfiguration
>>
>> On Sun, Nov 24, 2019 at 11:21 PM Bernd Eckenfels <ecki at zusammenkunft.net>
>> wrote:
>>
>>> Hello Anuraag,
>>>
>>> The patch looks like a good idea (especially the additional cleanup for
>>> nanos and arraylist) Just a minor thing I noticed there are two comments
>>> talking about „comma and space“ but the code below will only tokenize by
>>> space. Imguess the comment needs to be fixed, for the next review round.
>>>
>>> Gruss
>>> Bernd
>>> --
>>> http://bernd.eckenfels.net
>>>
>>> ------------------------------
>>> *Von:* net-dev <net-dev-bounces at openjdk.java.net> im Auftrag von
>>> Anuraag Agrawal <anuraaga at gmail.com>
>>> *Gesendet:* Sonntag, November 24, 2019 10:47 AM
>>> *An:* net-dev at openjdk.java.net
>>> *Betreff:* [PATCH] 7006496: Use modern Windows API to retrieve OS DNS
>>> servers
>>>
>>> Hello,
>>>
>>> While investigating DNS resolution failure using Netty (
>>> https://github.com/netty/netty/issues/9796), I came across an old JDK
>>> bug where on Windows, the list of OS name servers includes those for
>>> disabled interfaces (https://bugs.openjdk.java.net/browse/JDK-7006496).
>>> This is problematic since it will often include values from a previously
>>> registered network that is not available anymore, hence resolution requests
>>> would be guaranteed to fail.
>>>
>>> The current approach reads DNS name servers from the registry, where it
>>> isn't possible to read whether an adapter is actually enabled or not.
>>> However, Windows Vista+ (minimum JDK8+ supported Windows) include an API
>>> that can be used to examine whether an adapter is currently enabled, and
>>> also return its DNS servers. So I've created this patch to update the name
>>> server lookup to use this technique. I can confirm that now only name
>>> servers from enabled adapters are loaded. A side effect is the previous
>>> approach could only read IPv4 - now IPv6 DNS servers are also loaded. The
>>> unix implementation seems to do this too, so I don't think this should
>>> cause issues but I can filter to only IPv4 to be more conservative if
>>> desired.
>>>
>>> I have also cleaned some low hanging fruit in what seems to be very old
>>> code
>>>
>>> - Use ArrayList instead of LinkedList since it can be accurately
>>> preallocated and is not mutated
>>> - Use nanoTime instead of currentTimeMillis for refresh timer to not
>>> cause problems during OS time changes.
>>> - Simplify tokenizer to only tokenize on space, there is never a comma
>>> separated list passed to it as we create the list in our JNI code
>>>
>>> This is my first patch for OpenJDK - happy to accept any feedback.
>>>
>>> Thanks for the consideration.
>>>
>>> Inlined patch follows (also attached but I've had attached patch
>>> scrubbed when submitting to jmh-dev before...)
>>>
>>> diff --git
>>> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
>>> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
>>> index 2250b3158e..dde871cf19 100644
>>> ---
>>> a/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
>>> +++
>>> b/src/java.base/windows/classes/sun/net/dns/ResolverConfigurationImpl.java
>>> @@ -25,9 +25,10 @@
>>>
>>> package sun.net.dns;
>>>
>>> +import java.util.ArrayList;
>>> import java.util.List;
>>> -import java.util.LinkedList;
>>> import java.util.StringTokenizer;
>>> +import java.util.concurrent.TimeUnit;
>>>
>>> /*
>>> * An implementation of sun.net.ResolverConfiguration for Windows.
>>> @@ -50,30 +51,65 @@ public class ResolverConfigurationImpl
>>>
>>> // Cache timeout (120 seconds) - should be converted into property
>>> // or configured as preference in the future.
>>> - private static final int TIMEOUT = 120000;
>>> + private static final long TIMEOUT_NANOS =
>>> TimeUnit.SECONDS.toNanos(120);
>>>
>>> // DNS suffix list and name servers populated by native method
>>> private static String os_searchlist;
>>> private static String os_nameservers;
>>>
>>> // Cached lists
>>> - private static LinkedList<String> searchlist;
>>> - private static LinkedList<String> nameservers;
>>> + private static ArrayList<String> searchlist;
>>> + private static ArrayList<String> nameservers;
>>>
>>> - // Parse string that consists of token delimited by space or commas
>>> - // and return LinkedHashMap
>>> - private LinkedList<String> stringToList(String str) {
>>> - LinkedList<String> ll = new LinkedList<>();
>>> + // Parse string that consists of token delimited by space
>>> + // and return ArrayList
>>> + private ArrayList<String> stringToList(String str) {
>>> + ArrayList<String> l = allocateListForDelimitedString(str);
>>>
>>> // comma and space are valid delimiters
>>> - StringTokenizer st = new StringTokenizer(str, ", ");
>>> + StringTokenizer st = new StringTokenizer(str, " ");
>>> while (st.hasMoreTokens()) {
>>> String s = st.nextToken();
>>> - if (!ll.contains(s)) {
>>> - ll.add(s);
>>> + if (!l.contains(s)) {
>>> + l.add(s);
>>> }
>>> }
>>> - return ll;
>>> + return l;
>>> + }
>>> +
>>> + // Parse string that consists of token delimited by space
>>> + // and return ArrayList. Converts IPv6 addresses to BSD-style.
>>> + private ArrayList<String> addressesToList(String str) {
>>> + ArrayList<String> l = allocateListForDelimitedString(str);
>>> +
>>> + // comma and space are valid delimiters
>>> + StringTokenizer st = new StringTokenizer(str, " ");
>>> + while (st.hasMoreTokens()) {
>>> + String s = st.nextToken();
>>> + if (!s.isEmpty()) {
>>> + if (s.indexOf(':') >= 0 && s.charAt(0) != '[') {
>>> + // Not BSD style
>>> + s = '[' + s + ']';
>>> + }
>>> + if (!l.contains(s)) {
>>> + l.add(s);
>>> + }
>>> + }
>>> + }
>>> + return l;
>>> + }
>>> +
>>> + private ArrayList<String> allocateListForDelimitedString(String
>>> str) {
>>> + int num = 0;
>>> + for (int i = 0; i < str.length(); i++) {
>>> + char c = str.charAt(i);
>>> + // String is space separated list of items
>>> + if (c == ' ') {
>>> + num++;
>>> + }
>>> + }
>>> + // Actual num is number of delimiters + 1
>>> + return new ArrayList<String>(num + 1);
>>> }
>>>
>>> // Load DNS configuration from OS
>>> @@ -88,8 +124,8 @@ public class ResolverConfigurationImpl
>>> changed = false;
>>> } else {
>>> if (lastRefresh >= 0) {
>>> - long currTime = System.currentTimeMillis();
>>> - if ((currTime - lastRefresh) < TIMEOUT) {
>>> + long currTime = System.nanoTime();
>>> + if ((currTime - lastRefresh) < TIMEOUT_NANOS) {
>>> return;
>>> }
>>> }
>>> @@ -100,9 +136,9 @@ public class ResolverConfigurationImpl
>>> //
>>> loadDNSconfig0();
>>>
>>> - lastRefresh = System.currentTimeMillis();
>>> + lastRefresh = System.nanoTime();
>>> searchlist = stringToList(os_searchlist);
>>> - nameservers = stringToList(os_nameservers);
>>> + nameservers = addressesToList(os_nameservers);
>>> os_searchlist = null; // can be GC'ed
>>> os_nameservers = null;
>>> }
>>> diff --git
>>> a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
>>> b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
>>> index f2368bafcb..297a1561ef 100644
>>> --- a/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
>>> +++ b/src/java.base/windows/native/libnet/NetworkInterface_winXP.c
>>> @@ -73,8 +73,8 @@ const int MAX_TRIES = 3;
>>> * for each adapter on the system. Returned in *adapters.
>>> * Buffer is malloc'd and must be freed (unless error returned)
>>> */
>>> -static int getAdapters (JNIEnv *env, IP_ADAPTER_ADDRESSES **adapters) {
>>> - DWORD ret, flags;
>>> +int getAdapters (JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES
>>> **adapters) {
>>> + DWORD ret;
>>> IP_ADAPTER_ADDRESSES *adapterInfo;
>>> ULONG len;
>>> int try;
>>> @@ -87,9 +87,6 @@ static int getAdapters (JNIEnv *env,
>>> IP_ADAPTER_ADDRESSES **adapters) {
>>> }
>>>
>>> len = BUFF_SIZE;
>>> - flags = GAA_FLAG_SKIP_DNS_SERVER;
>>> - flags |= GAA_FLAG_SKIP_MULTICAST;
>>> - flags |= GAA_FLAG_INCLUDE_PREFIX;
>>> ret = GetAdaptersAddresses(AF_UNSPEC, flags, NULL, adapterInfo,
>>> &len);
>>>
>>> for (try = 0; ret == ERROR_BUFFER_OVERFLOW && try < MAX_TRIES;
>>> ++try) {
>>> @@ -240,7 +237,7 @@ static int ipinflen = 2048;
>>> */
>>> int getAllInterfacesAndAddresses (JNIEnv *env, netif **netifPP)
>>> {
>>> - DWORD ret;
>>> + DWORD ret, flags;
>>> MIB_IPADDRTABLE *tableP;
>>> IP_ADAPTER_ADDRESSES *ptr, *adapters=NULL;
>>> ULONG len=ipinflen, count=0;
>>> @@ -296,7 +293,11 @@ int getAllInterfacesAndAddresses (JNIEnv *env,
>>> netif **netifPP)
>>> }
>>> }
>>> free(tableP);
>>> - ret = getAdapters (env, &adapters);
>>> +
>>> + flags = GAA_FLAG_SKIP_DNS_SERVER;
>>> + flags |= GAA_FLAG_SKIP_MULTICAST;
>>> + flags |= GAA_FLAG_INCLUDE_PREFIX;
>>> + ret = getAdapters (env, flags, &adapters);
>>> if (ret != ERROR_SUCCESS) {
>>> goto err;
>>> }
>>> diff --git
>>> a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
>>> b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
>>> index 13b28044a5..83100aa9ad 100644
>>> --- a/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
>>> +++ b/src/java.base/windows/native/libnet/ResolverConfigurationImpl.c
>>> @@ -30,6 +30,7 @@
>>> #include <iprtrmib.h>
>>> #include <time.h>
>>> #include <assert.h>
>>> +#include <winsock2.h>
>>> #include <iphlpapi.h>
>>>
>>> #include "jni_util.h"
>>> @@ -48,6 +49,8 @@
>>> static jfieldID searchlistID;
>>> static jfieldID nameserversID;
>>>
>>> +extern int getAdapters(JNIEnv *env, int flags, IP_ADAPTER_ADDRESSES
>>> **adapters);
>>> +
>>> /*
>>> * Utility routine to append s2 to s1 with a space delimiter.
>>> * strappend(s1="abc", "def") => "abc def"
>>> @@ -72,29 +75,19 @@ void strappend(char *s1, char *s2) {
>>> }
>>>
>>> /*
>>> - * Windows 2000/XP
>>> - *
>>> - * Use registry approach based on settings described in Appendix C
>>> - * of "Microsoft Windows 2000 TCP/IP Implementation Details".
>>> - *
>>> - * DNS suffix list is obtained from SearchList registry setting. If
>>> - * this is not specified we compile suffix list based on the
>>> - * per-connection domain suffix.
>>> - *
>>> - * DNS name servers and domain settings are on a per-connection
>>> - * basic. We therefore enumerate the network adapters to get the
>>> - * names of each adapter and then query the corresponding registry
>>> - * settings to obtain NameServer/DhcpNameServer and Domain/DhcpDomain.
>>> + * Use DNS server addresses returned by GetAdaptersAddresses for
>>> currently
>>> + * active interfaces.
>>> */
>>> -static int loadConfig(char *sl, char *ns) {
>>> - IP_ADAPTER_INFO *adapterP;
>>> - ULONG size;
>>> - DWORD ret;
>>> +static int loadConfig(JNIEnv *env, char *sl, char *ns) {
>>> + IP_ADAPTER_ADDRESSES *adapters, *adapter;
>>> + IP_ADAPTER_DNS_SERVER_ADDRESS *dnsServer;
>>> + SOCKADDR *address;
>>> + IP_ADAPTER_DNS_SUFFIX *suffix;
>>> + DWORD ret, flags;
>>> DWORD dwLen;
>>> ULONG ulType;
>>> char result[MAX_STR_LEN];
>>> HANDLE hKey;
>>> - int gotSearchList = 0;
>>>
>>> /*
>>> * First see if there is a global suffix list specified.
>>> @@ -112,122 +105,58 @@ static int loadConfig(char *sl, char *ns) {
>>> assert(ulType == REG_SZ);
>>> if (strlen(result) > 0) {
>>> strappend(sl, result);
>>> - gotSearchList = 1;
>>> }
>>> }
>>> RegCloseKey(hKey);
>>> }
>>>
>>> - /*
>>> - * Ask the IP Helper library to enumerate the adapters
>>> - */
>>> - size = sizeof(IP_ADAPTER_INFO);
>>> - adapterP = (IP_ADAPTER_INFO *)malloc(size);
>>> - if (adapterP == NULL) {
>>> - return STS_ERROR;
>>> - }
>>> - ret = GetAdaptersInfo(adapterP, &size);
>>> - if (ret == ERROR_BUFFER_OVERFLOW) {
>>> - IP_ADAPTER_INFO *newAdapterP = (IP_ADAPTER_INFO
>>> *)realloc(adapterP, size);
>>> - if (newAdapterP == NULL) {
>>> - free(adapterP);
>>> - return STS_ERROR;
>>> - }
>>> - adapterP = newAdapterP;
>>>
>>> - ret = GetAdaptersInfo(adapterP, &size);
>>> + // We only need DNS server addresses so skip everything else.
>>> + flags = GAA_FLAG_SKIP_UNICAST;
>>> + flags |= GAA_FLAG_SKIP_ANYCAST;
>>> + flags |= GAA_FLAG_SKIP_MULTICAST;
>>> + flags |= GAA_FLAG_SKIP_FRIENDLY_NAME;
>>> + ret = getAdapters(env, flags, &adapters);
>>> + if (ret != ERROR_SUCCESS) {
>>> + return STS_ERROR;
>>> }
>>>
>>> - /*
>>> - * Iterate through the list of adapters as registry settings are
>>> - * keyed on the adapter name (GUID).
>>> - */
>>> - if (ret == ERROR_SUCCESS) {
>>> - IP_ADAPTER_INFO *curr = adapterP;
>>> - while (curr != NULL) {
>>> - char key[MAX_STR_LEN];
>>> -
>>> - sprintf(key,
>>> -
>>> "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces\\%s",
>>> - curr->AdapterName);
>>> -
>>> - ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
>>> - key,
>>> - 0,
>>> - KEY_READ,
>>> - (PHKEY)&hKey);
>>> - if (ret == ERROR_SUCCESS) {
>>> - DWORD enableDhcp = 0;
>>> -
>>> - /*
>>> - * Is DHCP enabled on this interface
>>> - */
>>> - dwLen = sizeof(enableDhcp);
>>> - ret = RegQueryValueEx(hKey, "EnableDhcp", NULL, &ulType,
>>> - (LPBYTE)&enableDhcp, &dwLen);
>>> -
>>> - /*
>>> - * If we don't have the suffix list when get the Domain
>>> - * or DhcpDomain. If DHCP is enabled then Domain
>>> overides
>>> - * DhcpDomain
>>> - */
>>> - if (!gotSearchList) {
>>> - result[0] = '\0';
>>> - dwLen = sizeof(result);
>>> - ret = RegQueryValueEx(hKey, "Domain", NULL, &ulType,
>>> - (LPBYTE)&result, &dwLen);
>>> - if (((ret != ERROR_SUCCESS) || (strlen(result) ==
>>> 0)) &&
>>> - enableDhcp) {
>>> - dwLen = sizeof(result);
>>> - ret = RegQueryValueEx(hKey, "DhcpDomain", NULL,
>>> &ulType,
>>> - (LPBYTE)&result, &dwLen);
>>> - }
>>> - if (ret == ERROR_SUCCESS) {
>>> - assert(ulType == REG_SZ);
>>> - strappend(sl, result);
>>> - }
>>> - }
>>> -
>>> - /*
>>> - * Get DNS servers based on NameServer or DhcpNameServer
>>> - * registry setting. If NameServer is set then it
>>> overrides
>>> - * DhcpNameServer (even if DHCP is enabled).
>>> - */
>>> - result[0] = '\0';
>>> + adapter = adapters;
>>> + while (adapter != NULL) {
>>> + // Only load config from enabled adapters.
>>> + if (adapter->OperStatus == IfOperStatusUp) {
>>> + dnsServer = adapter->FirstDnsServerAddress;
>>> + while (dnsServer != NULL) {
>>> + address = dnsServer->Address.lpSockaddr;
>>> dwLen = sizeof(result);
>>> - ret = RegQueryValueEx(hKey, "NameServer", NULL, &ulType,
>>> - (LPBYTE)&result, &dwLen);
>>> - if (((ret != ERROR_SUCCESS) || (strlen(result) == 0)) &&
>>> - enableDhcp) {
>>> - dwLen = sizeof(result);
>>> - ret = RegQueryValueEx(hKey, "DhcpNameServer", NULL,
>>> &ulType,
>>> - (LPBYTE)&result, &dwLen);
>>> - }
>>> - if (ret == ERROR_SUCCESS) {
>>> - assert(ulType == REG_SZ);
>>> + ret =
>>> WSAAddressToStringA(dnsServer->Address.lpSockaddr,
>>> + dnsServer->Address.iSockaddrLength, NULL,
>>> + result, &dwLen);
>>> + if (ret == 0) {
>>> strappend(ns, result);
>>> }
>>>
>>> - /*
>>> - * Finished with this registry key
>>> - */
>>> - RegCloseKey(hKey);
>>> + dnsServer = dnsServer->Next;
>>> }
>>>
>>> - /*
>>> - * Onto the next adapeter
>>> - */
>>> - curr = curr->Next;
>>> + // Add connection-specific search domains in addition to
>>> global one.
>>> + suffix = adapter->FirstDnsSuffix;
>>> + while (suffix != NULL) {
>>> + ret = WideCharToMultiByte(CP_UTF8, 0, suffix->String,
>>> -1,
>>> + result, sizeof(result), NULL, NULL);
>>> + if (ret != 0) {
>>> + strappend(sl, result);
>>> + }
>>> +
>>> + suffix = suffix->Next;
>>> + }
>>> }
>>> - }
>>>
>>> - /*
>>> - * Free the adpater structure
>>> - */
>>> - if (adapterP) {
>>> - free(adapterP);
>>> + adapter = adapter->Next;
>>> }
>>>
>>> + free(adapters);
>>> +
>>> return STS_SL_FOUND & STS_NS_FOUND;
>>> }
>>>
>>> @@ -260,7 +189,7 @@
>>> Java_sun_net_dns_ResolverConfigurationImpl_loadDNSconfig0(JNIEnv *env,
>>> jclass cl
>>> searchlist[0] = '\0';
>>> nameservers[0] = '\0';
>>>
>>> - if (loadConfig(searchlist, nameservers) != STS_ERROR) {
>>> + if (loadConfig(env, searchlist, nameservers) != STS_ERROR) {
>>>
>>> /*
>>> * Populate static fields in
>>> sun.net.DefaultResolverConfiguration
>>>
>>
>>
>>
>
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