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1   /*
2    * Copyright 2014 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   https://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.util.internal;
17  
18  import io.netty.util.CharsetUtil;
19  import io.netty.util.internal.logging.InternalLogger;
20  import io.netty.util.internal.logging.InternalLoggerFactory;
21  
22  import java.io.ByteArrayOutputStream;
23  import java.io.Closeable;
24  import java.io.File;
25  import java.io.FileNotFoundException;
26  import java.io.FileOutputStream;
27  import java.io.IOException;
28  import java.io.InputStream;
29  import java.io.OutputStream;
30  import java.lang.reflect.Method;
31  import java.net.URL;
32  import java.security.AccessController;
33  import java.security.MessageDigest;
34  import java.security.NoSuchAlgorithmException;
35  import java.security.PrivilegedAction;
36  import java.util.ArrayList;
37  import java.util.Arrays;
38  import java.util.Collections;
39  import java.util.EnumSet;
40  import java.util.Enumeration;
41  import java.util.List;
42  import java.util.Set;
43  
44  /**
45   * Helper class to load JNI resources.
46   *
47   */
48  public final class NativeLibraryLoader {
49  
50      private static final InternalLogger logger = InternalLoggerFactory.getInstance(NativeLibraryLoader.class);
51  
52      private static final String NATIVE_RESOURCE_HOME = "META-INF/native/";
53      private static final File WORKDIR;
54      private static final boolean DELETE_NATIVE_LIB_AFTER_LOADING;
55      private static final boolean TRY_TO_PATCH_SHADED_ID;
56      private static final boolean DETECT_NATIVE_LIBRARY_DUPLICATES;
57  
58      // Just use a-Z and numbers as valid ID bytes.
59      private static final byte[] UNIQUE_ID_BYTES =
60              "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".getBytes(CharsetUtil.US_ASCII);
61  
62      static {
63          String workdir = SystemPropertyUtil.get("io.netty.native.workdir");
64          if (workdir != null) {
65              File f = new File(workdir);
66              f.mkdirs();
67  
68              try {
69                  f = f.getAbsoluteFile();
70              } catch (Exception ignored) {
71                  // Good to have an absolute path, but it's OK.
72              }
73  
74              WORKDIR = f;
75              logger.debug("-Dio.netty.native.workdir: " + WORKDIR);
76          } else {
77              WORKDIR = PlatformDependent.tmpdir();
78              logger.debug("-Dio.netty.native.workdir: " + WORKDIR + " (io.netty.tmpdir)");
79          }
80  
81          DELETE_NATIVE_LIB_AFTER_LOADING = SystemPropertyUtil.getBoolean(
82                  "io.netty.native.deleteLibAfterLoading", true);
83          logger.debug("-Dio.netty.native.deleteLibAfterLoading: {}", DELETE_NATIVE_LIB_AFTER_LOADING);
84  
85          TRY_TO_PATCH_SHADED_ID = SystemPropertyUtil.getBoolean(
86                  "io.netty.native.tryPatchShadedId", true);
87          logger.debug("-Dio.netty.native.tryPatchShadedId: {}", TRY_TO_PATCH_SHADED_ID);
88  
89          DETECT_NATIVE_LIBRARY_DUPLICATES = SystemPropertyUtil.getBoolean(
90                  "io.netty.native.detectNativeLibraryDuplicates", true);
91          logger.debug("-Dio.netty.native.detectNativeLibraryDuplicates: {}", DETECT_NATIVE_LIBRARY_DUPLICATES);
92      }
93  
94      /**
95       * Loads the first available library in the collection with the specified
96       * {@link ClassLoader}.
97       *
98       * @throws IllegalArgumentException
99       *         if none of the given libraries load successfully.
100      */
101     public static void loadFirstAvailable(ClassLoader loader, String... names) {
102         List<Throwable> suppressed = new ArrayList<Throwable>();
103         for (String name : names) {
104             try {
105                 load(name, loader);
106                 logger.debug("Loaded library with name '{}'", name);
107                 return;
108             } catch (Throwable t) {
109                 suppressed.add(t);
110             }
111         }
112 
113         IllegalArgumentException iae =
114                 new IllegalArgumentException("Failed to load any of the given libraries: " + Arrays.toString(names));
115         ThrowableUtil.addSuppressedAndClear(iae, suppressed);
116         throw iae;
117     }
118 
119     /**
120      * Calculates the mangled shading prefix added to this class's full name.
121      *
122      * <p>This method mangles the package name as follows, so we can unmangle it back later:
123      * <ul>
124      *   <li>{@code _} to {@code _1}</li>
125      *   <li>{@code .} to {@code _}</li>
126      * </ul>
127      *
128      * <p>Note that we don't mangle non-ASCII characters here because it's extremely unlikely to have
129      * a non-ASCII character in a package name. For more information, see:
130      * <ul>
131      *   <li><a href="https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/design.html">JNI
132      *       specification</a></li>
133      *   <li>{@code parsePackagePrefix()} in {@code netty_jni_util.c}.</li>
134      * </ul>
135      *
136      * @throws UnsatisfiedLinkError if the shader used something other than a prefix
137      */
138     private static String calculateMangledPackagePrefix() {
139         String maybeShaded = NativeLibraryLoader.class.getName();
140         // Use ! instead of . to avoid shading utilities from modifying the string
141         String expected = "io!netty!util!internal!NativeLibraryLoader".replace('!', '.');
142         if (!maybeShaded.endsWith(expected)) {
143             throw new UnsatisfiedLinkError(String.format(
144                     "Could not find prefix added to %s to get %s. When shading, only adding a "
145                     + "package prefix is supported", expected, maybeShaded));
146         }
147         return maybeShaded.substring(0, maybeShaded.length() - expected.length())
148                           .replace("_", "_1")
149                           .replace('.', '_');
150     }
151 
152     /**
153      * Load the given library with the specified {@link ClassLoader}
154      */
155     public static void load(String originalName, ClassLoader loader) {
156         String mangledPackagePrefix = calculateMangledPackagePrefix();
157         String name = mangledPackagePrefix + originalName;
158         List<Throwable> suppressed = new ArrayList<Throwable>();
159         try {
160             // first try to load from java.library.path
161             loadLibrary(loader, name, false);
162             return;
163         } catch (Throwable ex) {
164             suppressed.add(ex);
165         }
166 
167         String libname = System.mapLibraryName(name);
168         String path = NATIVE_RESOURCE_HOME + libname;
169 
170         InputStream in = null;
171         OutputStream out = null;
172         File tmpFile = null;
173         URL url = getResource(path, loader);
174         try {
175             if (url == null) {
176                 if (PlatformDependent.isOsx()) {
177                     String fileName = path.endsWith(".jnilib") ? NATIVE_RESOURCE_HOME + "lib" + name + ".dynlib" :
178                             NATIVE_RESOURCE_HOME + "lib" + name + ".jnilib";
179                     url = getResource(fileName, loader);
180                     if (url == null) {
181                         FileNotFoundException fnf = new FileNotFoundException(fileName);
182                         ThrowableUtil.addSuppressedAndClear(fnf, suppressed);
183                         throw fnf;
184                     }
185                 } else {
186                     FileNotFoundException fnf = new FileNotFoundException(path);
187                     ThrowableUtil.addSuppressedAndClear(fnf, suppressed);
188                     throw fnf;
189                 }
190             }
191 
192             int index = libname.lastIndexOf('.');
193             String prefix = libname.substring(0, index);
194             String suffix = libname.substring(index);
195 
196             tmpFile = PlatformDependent.createTempFile(prefix, suffix, WORKDIR);
197             in = url.openStream();
198             out = new FileOutputStream(tmpFile);
199 
200             byte[] buffer = new byte[8192];
201             int length;
202             while ((length = in.read(buffer)) > 0) {
203                 out.write(buffer, 0, length);
204             }
205             out.flush();
206 
207             if (shouldShadedLibraryIdBePatched(mangledPackagePrefix)) {
208                 // Let's try to patch the id and re-sign it. This is a best-effort and might fail if a
209                 // SecurityManager is setup or the right executables are not installed :/
210                 tryPatchShadedLibraryIdAndSign(tmpFile, originalName);
211             }
212 
213             // Close the output stream before loading the unpacked library,
214             // because otherwise Windows will refuse to load it when it's in use by other process.
215             closeQuietly(out);
216             out = null;
217 
218             loadLibrary(loader, tmpFile.getPath(), true);
219         } catch (UnsatisfiedLinkError e) {
220             try {
221                 if (tmpFile != null && tmpFile.isFile() && tmpFile.canRead() &&
222                     !NoexecVolumeDetector.canExecuteExecutable(tmpFile)) {
223                     // Pass "io.netty.native.workdir" as an argument to allow shading tools to see
224                     // the string. Since this is printed out to users to tell them what to do next,
225                     // we want the value to be correct even when shading.
226                     logger.info("{} exists but cannot be executed even when execute permissions set; " +
227                                 "check volume for \"noexec\" flag; use -D{}=[path] " +
228                                 "to set native working directory separately.",
229                                 tmpFile.getPath(), "io.netty.native.workdir");
230                 }
231             } catch (Throwable t) {
232                 suppressed.add(t);
233                 logger.debug("Error checking if {} is on a file store mounted with noexec", tmpFile, t);
234             }
235             // Re-throw to fail the load
236             ThrowableUtil.addSuppressedAndClear(e, suppressed);
237             throw e;
238         } catch (Exception e) {
239             UnsatisfiedLinkError ule = new UnsatisfiedLinkError("could not load a native library: " + name);
240             ule.initCause(e);
241             ThrowableUtil.addSuppressedAndClear(ule, suppressed);
242             throw ule;
243         } finally {
244             closeQuietly(in);
245             closeQuietly(out);
246             // After we load the library it is safe to delete the file.
247             // We delete the file immediately to free up resources as soon as possible,
248             // and if this fails fallback to deleting on JVM exit.
249             if (tmpFile != null && (!DELETE_NATIVE_LIB_AFTER_LOADING || !tmpFile.delete())) {
250                 tmpFile.deleteOnExit();
251             }
252         }
253     }
254 
255     private static URL getResource(String path, ClassLoader loader) {
256         final Enumeration<URL> urls;
257         try {
258             if (loader == null) {
259                 urls = ClassLoader.getSystemResources(path);
260             } else {
261                 urls = loader.getResources(path);
262             }
263         } catch (IOException iox) {
264             throw new RuntimeException("An error occurred while getting the resources for " + path, iox);
265         }
266 
267         List<URL> urlsList = Collections.list(urls);
268         int size = urlsList.size();
269         switch (size) {
270             case 0:
271                 return null;
272             case 1:
273                 return urlsList.get(0);
274             default:
275                 if (DETECT_NATIVE_LIBRARY_DUPLICATES) {
276                     try {
277                         MessageDigest md = MessageDigest.getInstance("SHA-256");
278                         // We found more than 1 resource with the same name. Let's check if the content of the file is
279                         // the same as in this case it will not have any bad effect.
280                         URL url = urlsList.get(0);
281                         byte[] digest = digest(md, url);
282                         boolean allSame = true;
283                         if (digest != null) {
284                             for (int i = 1; i < size; i++) {
285                                 byte[] digest2 = digest(md, urlsList.get(i));
286                                 if (digest2 == null || !Arrays.equals(digest, digest2)) {
287                                     allSame = false;
288                                     break;
289                                 }
290                             }
291                         } else {
292                             allSame = false;
293                         }
294                         if (allSame) {
295                             return url;
296                         }
297                     } catch (NoSuchAlgorithmException e) {
298                         logger.debug("Don't support SHA-256, can't check if resources have same content.", e);
299                     }
300 
301                     throw new IllegalStateException(
302                             "Multiple resources found for '" + path + "' with different content: " + urlsList);
303                 } else {
304                     logger.warn("Multiple resources found for '" + path + "' with different content: " +
305                             urlsList + ". Please fix your dependency graph.");
306                     return urlsList.get(0);
307                 }
308         }
309     }
310 
311     private static byte[] digest(MessageDigest digest, URL url) {
312         InputStream in = null;
313         try {
314             in = url.openStream();
315             byte[] bytes = new byte[8192];
316             int i;
317             while ((i = in.read(bytes)) != -1) {
318                 digest.update(bytes, 0, i);
319             }
320             return digest.digest();
321         } catch (IOException e) {
322             logger.debug("Can't read resource.", e);
323             return null;
324         } finally {
325             closeQuietly(in);
326         }
327     }
328 
329     static void tryPatchShadedLibraryIdAndSign(File libraryFile, String originalName) {
330         String newId = new String(generateUniqueId(originalName.length()), CharsetUtil.UTF_8);
331         if (!tryExec("install_name_tool -id " + newId + " " + libraryFile.getAbsolutePath())) {
332             return;
333         }
334 
335         tryExec("codesign -s - " + libraryFile.getAbsolutePath());
336     }
337 
338     private static boolean tryExec(String cmd) {
339         try {
340             int exitValue = Runtime.getRuntime().exec(cmd).waitFor();
341             if (exitValue != 0) {
342                 logger.debug("Execution of '{}' failed: {}", cmd, exitValue);
343                 return false;
344             }
345             logger.debug("Execution of '{}' succeed: {}", cmd, exitValue);
346             return true;
347         } catch (InterruptedException e) {
348             Thread.currentThread().interrupt();
349         } catch (IOException e) {
350             logger.info("Execution of '{}' failed.", cmd, e);
351         } catch (SecurityException e) {
352             logger.error("Execution of '{}' failed.", cmd, e);
353         }
354         return false;
355     }
356 
357     private static boolean shouldShadedLibraryIdBePatched(String packagePrefix) {
358         return TRY_TO_PATCH_SHADED_ID && PlatformDependent.isOsx() && !packagePrefix.isEmpty();
359     }
360 
361     private static byte[] generateUniqueId(int length) {
362         byte[] idBytes = new byte[length];
363         for (int i = 0; i < idBytes.length; i++) {
364             // We should only use bytes as replacement that are in our UNIQUE_ID_BYTES array.
365             idBytes[i] = UNIQUE_ID_BYTES[PlatformDependent.threadLocalRandom()
366                     .nextInt(UNIQUE_ID_BYTES.length)];
367         }
368         return idBytes;
369     }
370 
371     /**
372      * Loading the native library into the specified {@link ClassLoader}.
373      * @param loader - The {@link ClassLoader} where the native library will be loaded into
374      * @param name - The native library path or name
375      * @param absolute - Whether the native library will be loaded by path or by name
376      */
377     private static void loadLibrary(final ClassLoader loader, final String name, final boolean absolute) {
378         Throwable suppressed = null;
379         try {
380             try {
381                 // Make sure the helper belongs to the target ClassLoader.
382                 final Class<?> newHelper = tryToLoadClass(loader, NativeLibraryUtil.class);
383                 loadLibraryByHelper(newHelper, name, absolute);
384                 logger.debug("Successfully loaded the library {}", name);
385                 return;
386             } catch (UnsatisfiedLinkError e) { // Should by pass the UnsatisfiedLinkError here!
387                 suppressed = e;
388             } catch (Exception e) {
389                 suppressed = e;
390             }
391             NativeLibraryUtil.loadLibrary(name, absolute);  // Fallback to local helper class.
392             logger.debug("Successfully loaded the library {}", name);
393         } catch (NoSuchMethodError nsme) {
394             if (suppressed != null) {
395                 ThrowableUtil.addSuppressed(nsme, suppressed);
396             }
397             rethrowWithMoreDetailsIfPossible(name, nsme);
398         } catch (UnsatisfiedLinkError ule) {
399             if (suppressed != null) {
400                 ThrowableUtil.addSuppressed(ule, suppressed);
401             }
402             throw ule;
403         }
404     }
405 
406     @SuppressJava6Requirement(reason = "Guarded by version check")
407     private static void rethrowWithMoreDetailsIfPossible(String name, NoSuchMethodError error) {
408         if (PlatformDependent.javaVersion() >= 7) {
409             throw new LinkageError(
410                     "Possible multiple incompatible native libraries on the classpath for '" + name + "'?", error);
411         }
412         throw error;
413     }
414 
415     private static void loadLibraryByHelper(final Class<?> helper, final String name, final boolean absolute)
416             throws UnsatisfiedLinkError {
417         Object ret = AccessController.doPrivileged(new PrivilegedAction<Object>() {
418             @Override
419             public Object run() {
420                 try {
421                     // Invoke the helper to load the native library, if succeed, then the native
422                     // library belong to the specified ClassLoader.
423                     Method method = helper.getMethod("loadLibrary", String.class, boolean.class);
424                     method.setAccessible(true);
425                     return method.invoke(null, name, absolute);
426                 } catch (Exception e) {
427                     return e;
428                 }
429             }
430         });
431         if (ret instanceof Throwable) {
432             Throwable t = (Throwable) ret;
433             assert !(t instanceof UnsatisfiedLinkError) : t + " should be a wrapper throwable";
434             Throwable cause = t.getCause();
435             if (cause instanceof UnsatisfiedLinkError) {
436                 throw (UnsatisfiedLinkError) cause;
437             }
438             UnsatisfiedLinkError ule = new UnsatisfiedLinkError(t.getMessage());
439             ule.initCause(t);
440             throw ule;
441         }
442     }
443 
444     /**
445      * Try to load the helper {@link Class} into specified {@link ClassLoader}.
446      * @param loader - The {@link ClassLoader} where to load the helper {@link Class}
447      * @param helper - The helper {@link Class}
448      * @return A new helper Class defined in the specified ClassLoader.
449      * @throws ClassNotFoundException Helper class not found or loading failed
450      */
451     private static Class<?> tryToLoadClass(final ClassLoader loader, final Class<?> helper)
452             throws ClassNotFoundException {
453         try {
454             return Class.forName(helper.getName(), false, loader);
455         } catch (ClassNotFoundException e1) {
456             if (loader == null) {
457                 // cannot defineClass inside bootstrap class loader
458                 throw e1;
459             }
460             try {
461                 // The helper class is NOT found in target ClassLoader, we have to define the helper class.
462                 final byte[] classBinary = classToByteArray(helper);
463                 return AccessController.doPrivileged(new PrivilegedAction<Class<?>>() {
464                     @Override
465                     public Class<?> run() {
466                         try {
467                             // Define the helper class in the target ClassLoader,
468                             //  then we can call the helper to load the native library.
469                             Method defineClass = ClassLoader.class.getDeclaredMethod("defineClass", String.class,
470                                     byte[].class, int.class, int.class);
471                             defineClass.setAccessible(true);
472                             return (Class<?>) defineClass.invoke(loader, helper.getName(), classBinary, 0,
473                                     classBinary.length);
474                         } catch (Exception e) {
475                             throw new IllegalStateException("Define class failed!", e);
476                         }
477                     }
478                 });
479             } catch (ClassNotFoundException e2) {
480                 ThrowableUtil.addSuppressed(e2, e1);
481                 throw e2;
482             } catch (RuntimeException e2) {
483                 ThrowableUtil.addSuppressed(e2, e1);
484                 throw e2;
485             } catch (Error e2) {
486                 ThrowableUtil.addSuppressed(e2, e1);
487                 throw e2;
488             }
489         }
490     }
491 
492     /**
493      * Load the helper {@link Class} as a byte array, to be redefined in specified {@link ClassLoader}.
494      * @param clazz - The helper {@link Class} provided by this bundle
495      * @return The binary content of helper {@link Class}.
496      * @throws ClassNotFoundException Helper class not found or loading failed
497      */
498     private static byte[] classToByteArray(Class<?> clazz) throws ClassNotFoundException {
499         String fileName = clazz.getName();
500         int lastDot = fileName.lastIndexOf('.');
501         if (lastDot > 0) {
502             fileName = fileName.substring(lastDot + 1);
503         }
504         URL classUrl = clazz.getResource(fileName + ".class");
505         if (classUrl == null) {
506             throw new ClassNotFoundException(clazz.getName());
507         }
508         byte[] buf = new byte[1024];
509         ByteArrayOutputStream out = new ByteArrayOutputStream(4096);
510         InputStream in = null;
511         try {
512             in = classUrl.openStream();
513             for (int r; (r = in.read(buf)) != -1;) {
514                 out.write(buf, 0, r);
515             }
516             return out.toByteArray();
517         } catch (IOException ex) {
518             throw new ClassNotFoundException(clazz.getName(), ex);
519         } finally {
520             closeQuietly(in);
521             closeQuietly(out);
522         }
523     }
524 
525     private static void closeQuietly(Closeable c) {
526         if (c != null) {
527             try {
528                 c.close();
529             } catch (IOException ignore) {
530                 // ignore
531             }
532         }
533     }
534 
535     private NativeLibraryLoader() {
536         // Utility
537     }
538 
539     private static final class NoexecVolumeDetector {
540 
541         @SuppressJava6Requirement(reason = "Usage guarded by java version check")
542         private static boolean canExecuteExecutable(File file) throws IOException {
543             if (PlatformDependent.javaVersion() < 7) {
544                 // Pre-JDK7, the Java API did not directly support POSIX permissions; instead of implementing a custom
545                 // work-around, assume true, which disables the check.
546                 return true;
547             }
548 
549             // If we can already execute, there is nothing to do.
550             if (file.canExecute()) {
551                 return true;
552             }
553 
554             // On volumes, with noexec set, even files with the executable POSIX permissions will fail to execute.
555             // The File#canExecute() method honors this behavior, probaby via parsing the noexec flag when initializing
556             // the UnixFileStore, though the flag is not exposed via a public API.  To find out if library is being
557             // loaded off a volume with noexec, confirm or add executalbe permissions, then check File#canExecute().
558 
559             // Note: We use FQCN to not break when netty is used in java6
560             Set<java.nio.file.attribute.PosixFilePermission> existingFilePermissions =
561                     java.nio.file.Files.getPosixFilePermissions(file.toPath());
562             Set<java.nio.file.attribute.PosixFilePermission> executePermissions =
563                     EnumSet.of(java.nio.file.attribute.PosixFilePermission.OWNER_EXECUTE,
564                             java.nio.file.attribute.PosixFilePermission.GROUP_EXECUTE,
565                             java.nio.file.attribute.PosixFilePermission.OTHERS_EXECUTE);
566             if (existingFilePermissions.containsAll(executePermissions)) {
567                 return false;
568             }
569 
570             Set<java.nio.file.attribute.PosixFilePermission> newPermissions = EnumSet.copyOf(existingFilePermissions);
571             newPermissions.addAll(executePermissions);
572             java.nio.file.Files.setPosixFilePermissions(file.toPath(), newPermissions);
573             return file.canExecute();
574         }
575 
576         private NoexecVolumeDetector() {
577             // Utility
578         }
579     }
580 }