Add android.system.Os.link for link(2).

Bug: 14683762
Change-Id: Ieeba1d2d0c5e9c05e85c6ffbaeb5a7febc69238c

6 files changed, 26 insertions, 0 deletions

diff --git a/luni/src/main/java/android/system/Os.java b/luni/src/main/java/android/system/Os.java
index 1197c73..e7613df 100644
--- a/luni/src/main/java/android/system/Os.java
+++ b/luni/src/main/java/android/system/Os.java
@@ -251,6 +251,11 @@ public final class Os {
   public static void lchown(String path, int uid, int gid) throws ErrnoException { Libcore.os.lchown(path, uid, gid); }
 
   /**
+   * See <a href="http://man7.org/linux/man-pages/man2/link.2.html">link(2)</a>.
+   */
+  public static void link(String oldPath, String newPath) throws ErrnoException { Libcore.os.link(oldPath, newPath); }
+
+  /**
    * See <a href="http://man7.org/linux/man-pages/man2/listen.2.html">listen(2)</a>.
    */
   public static void listen(FileDescriptor fd, int backlog) throws ErrnoException { Libcore.os.listen(fd, backlog); }
diff --git a/luni/src/main/java/libcore/io/BlockGuardOs.java b/luni/src/main/java/libcore/io/BlockGuardOs.java
index 238c5bd..0b04e2b 100644
--- a/luni/src/main/java/libcore/io/BlockGuardOs.java
+++ b/luni/src/main/java/libcore/io/BlockGuardOs.java
@@ -149,6 +149,11 @@ public class BlockGuardOs extends ForwardingOs {
         os.lchown(path, uid, gid);
     }
 
+    @Override public void link(String oldPath, String newPath) throws ErrnoException {
+        BlockGuard.getThreadPolicy().onWriteToDisk();
+        os.link(oldPath, newPath);
+    }
+
     @Override public long lseek(FileDescriptor fd, long offset, int whence) throws ErrnoException {
         BlockGuard.getThreadPolicy().onReadFromDisk();
         return os.lseek(fd, offset, whence);
diff --git a/luni/src/main/java/libcore/io/ForwardingOs.java b/luni/src/main/java/libcore/io/ForwardingOs.java
index 9a993c5..d09e442 100644
--- a/luni/src/main/java/libcore/io/ForwardingOs.java
+++ b/luni/src/main/java/libcore/io/ForwardingOs.java
@@ -100,6 +100,7 @@ public class ForwardingOs implements Os {
     public boolean isatty(FileDescriptor fd) { return os.isatty(fd); }
     public void kill(int pid, int signal) throws ErrnoException { os.kill(pid, signal); }
     public void lchown(String path, int uid, int gid) throws ErrnoException { os.lchown(path, uid, gid); }
+    public void link(String oldPath, String newPath) throws ErrnoException { os.link(oldPath, newPath); }
     public void listen(FileDescriptor fd, int backlog) throws ErrnoException { os.listen(fd, backlog); }
     public long lseek(FileDescriptor fd, long offset, int whence) throws ErrnoException { return os.lseek(fd, offset, whence); }
     public StructStat lstat(String path) throws ErrnoException { return os.lstat(path); }
diff --git a/luni/src/main/java/libcore/io/Os.java b/luni/src/main/java/libcore/io/Os.java
index e55ae5c..a537aeb 100644
--- a/luni/src/main/java/libcore/io/Os.java
+++ b/luni/src/main/java/libcore/io/Os.java
@@ -92,6 +92,7 @@ public interface Os {
     public boolean isatty(FileDescriptor fd);
     public void kill(int pid, int signal) throws ErrnoException;
     public void lchown(String path, int uid, int gid) throws ErrnoException;
+    public void link(String oldPath, String newPath) throws ErrnoException;
     public void listen(FileDescriptor fd, int backlog) throws ErrnoException;
     public long lseek(FileDescriptor fd, long offset, int whence) throws ErrnoException;
     public StructStat lstat(String path) throws ErrnoException;
diff --git a/luni/src/main/java/libcore/io/Posix.java b/luni/src/main/java/libcore/io/Posix.java
index 8d99f5e..7551190 100644
--- a/luni/src/main/java/libcore/io/Posix.java
+++ b/luni/src/main/java/libcore/io/Posix.java
@@ -94,6 +94,7 @@ public final class Posix implements Os {
     public native boolean isatty(FileDescriptor fd);
     public native void kill(int pid, int signal) throws ErrnoException;
     public native void lchown(String path, int uid, int gid) throws ErrnoException;
+    public native void link(String oldPath, String newPath) throws ErrnoException;
     public native void listen(FileDescriptor fd, int backlog) throws ErrnoException;
     public native long lseek(FileDescriptor fd, long offset, int whence) throws ErrnoException;
     public native StructStat lstat(String path) throws ErrnoException;
diff --git a/luni/src/main/native/libcore_io_Posix.cpp b/luni/src/main/native/libcore_io_Posix.cpp
index db1a886..b1217c0 100644
--- a/luni/src/main/native/libcore_io_Posix.cpp
+++ b/luni/src/main/native/libcore_io_Posix.cpp
@@ -922,6 +922,18 @@ static void Posix_lchown(JNIEnv* env, jobject, jstring javaPath, jint uid, jint
     throwIfMinusOne(env, "lchown", TEMP_FAILURE_RETRY(lchown(path.c_str(), uid, gid)));
 }
 
+static void Posix_link(JNIEnv* env, jobject, jstring javaOldPath, jstring javaNewPath) {
+    ScopedUtfChars oldPath(env, javaOldPath);
+    if (oldPath.c_str() == NULL) {
+        return;
+    }
+    ScopedUtfChars newPath(env, javaNewPath);
+    if (newPath.c_str() == NULL) {
+        return;
+    }
+    throwIfMinusOne(env, "link", TEMP_FAILURE_RETRY(link(oldPath.c_str(), newPath.c_str())));
+}
+
 static void Posix_listen(JNIEnv* env, jobject, jobject javaFd, jint backlog) {
     int fd = jniGetFDFromFileDescriptor(env, javaFd);
     throwIfMinusOne(env, "listen", TEMP_FAILURE_RETRY(listen(fd, backlog)));
@@ -1535,6 +1547,7 @@ static JNINativeMethod gMethods[] = {
     NATIVE_METHOD(Posix, isatty, "(Ljava/io/FileDescriptor;)Z"),
     NATIVE_METHOD(Posix, kill, "(II)V"),
     NATIVE_METHOD(Posix, lchown, "(Ljava/lang/String;II)V"),
+    NATIVE_METHOD(Posix, link, "(Ljava/lang/String;Ljava/lang/String;)V"),
     NATIVE_METHOD(Posix, listen, "(Ljava/io/FileDescriptor;I)V"),
     NATIVE_METHOD(Posix, lseek, "(Ljava/io/FileDescriptor;JI)J"),
     NATIVE_METHOD(Posix, lstat, "(Ljava/lang/String;)Landroid/system/StructStat;"),