X-Git-Url: http://git.megacz.com/?p=nestedvm.git;a=blobdiff_plain;f=src%2Forg%2Fibex%2Fnestedvm%2FUnixRuntime.java;h=0bc102809b0cb88ac0dda49f5854a35444cb5008;hp=0b50ee30b65315cd3500d455d6b3bf71d33bf1e3;hb=404ead23c2104bbed240370653a5308849b98905;hpb=18f9d34628d03afdf74b95ccd96e6e2e8441fb54

diff --git a/src/org/ibex/nestedvm/UnixRuntime.java b/src/org/ibex/nestedvm/UnixRuntime.java
index 0b50ee3..0bc1028 100644
--- a/src/org/ibex/nestedvm/UnixRuntime.java
+++ b/src/org/ibex/nestedvm/UnixRuntime.java
@@ -1,3 +1,7 @@
+// Copyright 2000-2005 the Contributors, as shown in the revision logs.
+// Licensed under the Apache Public Source License 2.0 ("the License").
+// You may not use this file except in compliance with the License.
+
 package org.ibex.nestedvm;
 
 import org.ibex.nestedvm.util.*;
@@ -6,6 +10,7 @@ import org.ibex.classgen.util.Sort;
 import java.io.*;
 import java.util.*;
 import java.net.*;
+import java.lang.reflect.*; // For lazily linked RuntimeCompiler
 
 // FEATURE: vfork
 
@@ -19,6 +24,7 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
     private GlobalState gs;
     public void setGlobalState(GlobalState gs) {
         if(state != STOPPED) throw new IllegalStateException("can't change GlobalState when running");
+        if(gs == null) throw new NullPointerException("gs is null");
         this.gs = gs;
     }
     
@@ -40,28 +46,9 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
         if(!exec) {
             gs = defaultGS;
             String userdir = Platform.getProperty("user.dir");
-            String nvroot = Platform.getProperty("nestedvm.root");
-            cwd = "";
-            if(userdir != null && nvroot == null) {
-                if(userdir.startsWith("/") && File.separatorChar == '/') {
-                    cwd = userdir.substring(1);
-                } else {
-                    Vector vec = new Vector();
-                    File root = HostFS.hostRootDir();
-                    String s = new File(userdir).getAbsolutePath();
-                    File d = new File(s);
-                    System.err.println(s);
-                    System.err.println(d);
-                    while(!d.equals(root)) {
-                        System.err.println("Got " + d.getName());
-                        vec.addElement(d.getName());
-                        if((s = d.getParent()) == null) break;
-                        d = new File(s);
-                    }
-                    if(s != null)
-                        for(int i=vec.size()-1;i>=0;i--) cwd += (String) vec.elementAt(i) + (i==0?"":"/");
-                }
-            }
+            cwd = (userdir == null || Platform.getProperty("nestedvm.root") != null) ? null : HostFS.reverseMap(userdir);
+            if(cwd == null) cwd = "/";
+            cwd = cwd.substring(1);
         }
     }
     
@@ -87,13 +74,16 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
     }
     
     String[] createEnv(String[] extra) {
-        String[] defaults = new String[6];
+        String[] defaults = new String[7];
         int n=0;
         if(extra == null) extra = new String[0];
+        String tmp;
         if(!envHas("USER",extra) && Platform.getProperty("user.name") != null)
             defaults[n++] = "USER=" + Platform.getProperty("user.name");
-        if(!envHas("HOME",extra) && Platform.getProperty("user.home") != null)
-            defaults[n++] = "HOME=" + Platform.getProperty("user.home");
+        if(!envHas("HOME",extra) && (tmp=Platform.getProperty("user.home")) != null && (tmp=HostFS.reverseMap(tmp)) != null)
+            defaults[n++] = "HOME=" + tmp;
+        if(!envHas("TMPDIR",extra) && (tmp=Platform.getProperty("java.io.tmpdir")) != null && (tmp=HostFS.reverseMap(tmp)) != null)
+            defaults[n++] = "TMPDIR=" + tmp;
         if(!envHas("SHELL",extra)) defaults[n++] = "SHELL=/bin/sh";
         if(!envHas("TERM",extra) && !win32Hacks)  defaults[n++] = "TERM=vt100";
         if(!envHas("TZ",extra))    defaults[n++] = "TZ=" + posixTZ();
@@ -161,7 +151,15 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
             case SYS_sendto: return sys_sendto(a,b,c,d,e,f);
             case SYS_recvfrom: return sys_recvfrom(a,b,c,d,e,f);
             case SYS_select: return sys_select(a,b,c,d,e);
-
+            case SYS_access: return sys_access(a,b);
+            case SYS_realpath: return sys_realpath(a,b);
+            case SYS_chown: return sys_chown(a,b,c);
+            case SYS_lchown: return sys_chown(a,b,c);
+            case SYS_fchown: return sys_fchown(a,b,c);
+            case SYS_chmod: return sys_chmod(a,b,c);
+            case SYS_fchmod: return sys_fchmod(a,b,c);
+            case SYS_umask: return sys_umask(a);
+            
             default: return super._syscall(syscall,a,b,c,d,e,f);
         }
     }
@@ -173,6 +171,38 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
     private int sys_getppid() {
         return parent == null ? 1 : parent.pid;
     }
+    
+    private int sys_chown(int fileAddr, int uid, int gid) {
+        return 0;
+    }
+    private int sys_lchown(int fileAddr, int uid, int gid) {
+        return 0;
+    }
+    private int sys_fchown(int fd, int uid, int gid) {
+        return 0;
+    }
+    private int sys_chmod(int fileAddr, int uid, int gid) {
+        return 0;
+    }
+    private int sys_fchmod(int fd, int uid, int gid) {
+        return 0;
+    }
+    private int sys_umask(int mask) {
+        return 0;
+    }
+    
+    private int sys_access(int cstring, int mode) throws ErrnoException, ReadFaultException {
+        // FEATURE: sys_access
+        return gs.stat(this,cstring(cstring)) == null ? -ENOENT : 0;
+    }
+    
+    private int sys_realpath(int inAddr, int outAddr) throws FaultException {
+        String s = normalizePath(cstring(inAddr));
+        byte[] b = getNullTerminatedBytes(s);
+        if(b.length > PATH_MAX) return -ERANGE;
+        copyout(b,outAddr,b.length);
+        return 0;
+    }
 
     // FEATURE: Signal handling
     // check flag only on backwards jumps to basic blocks without compulsatory checks 
@@ -360,43 +390,156 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
     private int sys_exec(int cpath, int cargv, int cenvp) throws ErrnoException, FaultException {
         return exec(normalizePath(cstring(cpath)),readStringArray(cargv),readStringArray(cenvp));
     }
+    
+    private final static Method runtimeCompilerCompile;
+    static {
+        Method m;
+        try {
+            m = Class.forName("org.ibex.nestedvm.RuntimeCompiler").getMethod("compile",new Class[]{Seekable.class,String.class,String.class});
+        } catch(NoSuchMethodException e) {
+            m = null;
+        } catch(ClassNotFoundException e) {
+            m = null;
+        }
+        runtimeCompilerCompile = m;
+    }
+            
+    public Class runtimeCompile(Seekable s, String sourceName) throws IOException {
+        if(runtimeCompilerCompile == null) {
+            if(STDERR_DIAG) System.err.println("WARNING: Exec attempted but RuntimeCompiler not found!");
+            return null;
+        }
         
-    private int exec(String normalizedPath, String[] argv, String[] envp) throws ErrnoException {
+        try {
+            return (Class) runtimeCompilerCompile.invoke(null,new Object[]{s,"unixruntime,maxinsnpermethod=256,lessconstants",sourceName});
+        } catch(IllegalAccessException e) {
+            e.printStackTrace();
+            return null;
+        } catch(InvocationTargetException e) {
+            Throwable t = e.getTargetException();
+            if(t instanceof IOException) throw (IOException) t;
+            if(t instanceof RuntimeException) throw (RuntimeException) t;
+            if(t instanceof Error) throw (Error) t;
+            if(STDERR_DIAG) t.printStackTrace();
+            return null;
+        }
+    }
+        
+    private int exec(String path, String[] argv, String[] envp) throws ErrnoException {
         if(argv.length == 0) argv = new String[]{""};
-
+        // HACK: Hideous hack to make a standalone busybox possible
+        if(path.equals("bin/busybox") && getClass().getName().endsWith("BusyBox"))
+            return execClass(getClass(),argv,envp);
+        
         // NOTE: For this little hack to work nestedvm.root MUST be "."
         /*try {
             System.err.println("Execing normalized path: " + normalizedPath);
             if(true) return exec(new Interpreter(normalizedPath),argv,envp);
         } catch(IOException e) { throw new Error(e); }*/
         
-        Object o = gs.exec(this,normalizedPath);
-        if(o == null) return -ENOENT;
-
-        if(o instanceof Class) {
-            Class c = (Class) o;
-            try {
-                UnixRuntime r = (UnixRuntime) c.getDeclaredConstructor(new Class[]{Boolean.TYPE}).newInstance(new Object[]{Boolean.TRUE});
-                return exec(r,argv,envp);
-            } catch(Exception e) {
-                e.printStackTrace();
-                return -ENOEXEC;
+        FStat fstat = gs.stat(this,path);
+        if(fstat == null) return -ENOENT;
+        GlobalState.CacheEnt ent = (GlobalState.CacheEnt) gs.execCache.get(path);
+        long mtime = fstat.mtime();
+        long size = fstat.size();
+        if(ent != null) {
+            //System.err.println("Found cached entry for " + path);
+            if(ent.time ==mtime && ent.size == size) {
+                if(ent.o instanceof Class)
+                    return execClass((Class) ent.o,argv,envp);
+                if(ent.o instanceof String[]) 
+                    return execScript(path,(String[]) ent.o,argv,envp);
+                throw new Error("should never happen");
             }
-        } else {
-            String[] command = (String[]) o;
-            String[] newArgv = new String[argv.length + command[1] != null ? 2 : 1];
-            int p = command[0].lastIndexOf('/');
-            newArgv[0] = p == -1 ? command[0] : command[0].substring(p+1);
-            p = 1;
-            if(command[1] != null) newArgv[p++] = command[1];
-            newArgv[p++] = "/" + normalizedPath;
-            for(int i=1;i<argv.length;i++) newArgv[p++] = argv[i];
-            return exec(command[0],newArgv,envp);
+            //System.err.println("Cache was out of date");
+            gs.execCache.remove(path);
+        }
+        
+        FD fd = gs.open(this,path,RD_ONLY,0);
+        if(fd == null) throw new ErrnoException(ENOENT);
+        Seekable s = fd.seekable();        
+        if(s == null) throw new ErrnoException(EACCES);
+        
+        byte[] buf = new byte[4096];
+        
+        try {
+            int n = s.read(buf,0,buf.length);
+            if(n == -1) throw new ErrnoException(ENOEXEC);
+            
+            switch(buf[0]) {
+                case '\177': // possible ELF
+                    if(n < 4) s.tryReadFully(buf,n,4-n);
+                    if(buf[1] != 'E' || buf[2] != 'L' || buf[3] != 'F') return -ENOEXEC;
+                    s.seek(0);
+                    if(STDERR_DIAG) System.err.println("Running RuntimeCompiler for " + path);
+                    Class c = runtimeCompile(s,path);
+                    if(STDERR_DIAG) System.err.println("RuntimeCompiler finished for " + path);
+                    if(c == null) throw new ErrnoException(ENOEXEC);
+                    gs.execCache.put(path,new GlobalState.CacheEnt(mtime,size,c));
+                    return execClass(c,argv,envp);
+                case '#':
+                    if(n == 1) {
+                        int n2 = s.read(buf,1,buf.length-1);
+                        if(n2 == -1) return -ENOEXEC;
+                        n += n2;
+                    }
+                    if(buf[1] != '!') return -ENOEXEC;
+                    int p = 2;
+                    n -= 2;
+                    OUTER: for(;;) {
+                        for(int i=p;i<p+n;i++) if(buf[i] == '\n') { p = i; break OUTER; }
+                            p += n;
+                        if(p == buf.length) break OUTER;
+                        n = s.read(buf,p,buf.length-p);
+                    }
+                    int cmdStart = 2;
+                    for(;cmdStart<p;cmdStart++) if(buf[cmdStart]!=' ') break;
+                    if(cmdStart == p) throw new ErrnoException(ENOEXEC);
+                    int argStart = cmdStart;
+                    for(;argStart<p;argStart++) if(buf[argStart] == ' ') break;
+                    int cmdEnd = argStart;
+                    while(argStart < p && buf[argStart] == ' ') argStart++;
+                    String[] command = new String[] {
+                        new String(buf,cmdStart,cmdEnd-cmdStart),
+                        argStart < p ? new String(buf,argStart,p-argStart) : null
+                    };
+                    gs.execCache.put(path,new GlobalState.CacheEnt(mtime,size,command));
+                    return execScript(path,command,argv,envp);
+                default:
+                    return -ENOEXEC;
+            }
+        } catch(IOException e) {
+            return -EIO;
+        } finally {
+            fd.close();
+        }        
+    }
+    
+    public int execScript(String path, String[] command, String[] argv, String[] envp) throws ErrnoException {
+        String[] newArgv = new String[argv.length-1 + (command[1] != null ? 3 : 2)];
+        int p = command[0].lastIndexOf('/');
+        newArgv[0] = p == -1 ? command[0] : command[0].substring(p+1);
+        newArgv[1] = "/" + path;
+        p = 2;
+        if(command[1] != null) newArgv[p++] = command[1];
+        for(int i=1;i<argv.length;i++) newArgv[p++] = argv[i];
+        if(p != newArgv.length) throw new Error("p != newArgv.length");
+        System.err.println("Execing: " + command[0]);
+        for(int i=0;i<newArgv.length;i++) System.err.println("execing [" + i + "] " + newArgv[i]);
+        return exec(command[0],newArgv,envp);
+    }
+    
+    public int execClass(Class c,String[] argv, String[] envp) {
+        try {
+            UnixRuntime r = (UnixRuntime) c.getDeclaredConstructor(new Class[]{Boolean.TYPE}).newInstance(new Object[]{Boolean.TRUE});
+            return exec(r,argv,envp);
+        } catch(Exception e) {
+            e.printStackTrace();
+            return -ENOEXEC;
         }
     }
     
     private int exec(UnixRuntime r, String[] argv, String[] envp) {     
-        
         //System.err.println("Execing " + r);
         for(int i=0;i<OPEN_MAX;i++) if(closeOnExec[i]) closeFD(i);
         r.fds = fds;
@@ -1013,7 +1156,9 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
         return 0;
     }
     
-    public static class GlobalState {            
+    public static final class GlobalState {
+        Hashtable execCache = new Hashtable();
+        
         final UnixRuntime[] tasks;
         int nextPID = 1;
         
@@ -1027,10 +1172,11 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
             if(defaultMounts) {
                 addMount("/",new HostFS());
                 addMount("/dev",new DevFS());
+                addMount("/resource",new ResourceFS());
             }
         }
         
-        private static class MP implements Sort.Comparable {
+        static class MP implements Sort.Comparable {
             public MP(String path, FS fs) { this.path = path; this.fs = fs; }
             public String path;
             public FS fs;
@@ -1116,106 +1262,12 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
         public final void mkdir(UnixRuntime r, String path, int mode) throws ErrnoException { fsop(FS.MKDIR,r,path,mode,0); }
         public final void unlink(UnixRuntime r, String path) throws ErrnoException { fsop(FS.UNLINK,r,path,0,0); }
         
-        private Hashtable execCache = new Hashtable();
         private static class CacheEnt {
             public final long time;
             public final long size;
             public final Object o;
             public CacheEnt(long time, long size, Object o) { this.time = time; this.size = size; this.o = o; }
         }
-
-        public synchronized Object exec(UnixRuntime r, String path) throws ErrnoException {
-            // HACK: Hideous hack to make a standalone busybox possible
-            if(path.equals("bin/busybox") && r.getClass().getName().endsWith("BusyBox")) return r.getClass();
-            
-            FStat fstat = stat(r,path);
-            if(fstat == null) return null;
-            long mtime = fstat.mtime();
-            long size = fstat.size();
-            CacheEnt ent = (CacheEnt) execCache.get(path);
-            if(ent != null) {
-                //System.err.println("Found cached entry for " + path);
-                if(ent.time == mtime && ent.size == size) return ent.o;
-                //System.err.println("Cache was out of date");
-                execCache.remove(path);
-            }
-            FD fd = open(r,path,RD_ONLY,0);
-            if(fd == null) return null;
-            Seekable s = fd.seekable();
-            
-            String[] command  = null;
-
-            if(s == null) throw new ErrnoException(EACCES);
-            byte[] buf = new byte[4096];
-            
-            try {
-                int n = s.read(buf,0,buf.length);
-                if(n == -1) throw new ErrnoException(ENOEXEC);
-                
-                switch(buf[0]) {
-                    case '\177': // possible ELF
-                        if(n < 4 && s.tryReadFully(buf,n,4-n) != 4-n) throw new ErrnoException(ENOEXEC);
-                        if(buf[1] != 'E' || buf[2] != 'L' || buf[3] != 'F') throw new ErrnoException(ENOEXEC);
-                        break;
-                    case '#':
-                        if(n == 1) {
-                            int n2 = s.read(buf,1,buf.length-1);
-                            if(n2 == -1) throw new ErrnoException(ENOEXEC);
-                            n += n2;
-                        }
-                        if(buf[1] != '!') throw new ErrnoException(ENOEXEC);
-                        int p = 2;
-                        n -= 2;
-                        OUTER: for(;;) {
-                            for(int i=p;i<p+n;i++) if(buf[i] == '\n') { p = i; break OUTER; }
-                            p += n;
-                            if(p == buf.length) break OUTER;
-                            n = s.read(buf,p,buf.length-p);
-                        }
-                        command = new String[2];
-                        int arg;
-                        for(arg=2;arg<p;arg++) if(buf[arg] == ' ') break;
-                        if(arg < p) {
-                            int cmdEnd = arg;
-                            while(arg < p && buf[arg] == ' ') arg++;
-                            command[0] = new String(buf,2,cmdEnd);
-                            command[1] = arg < p ? new String(buf,arg,p-arg) : null;
-                        } else {
-                            command[0] = new String(buf,2,p-2);
-                        }
-                        //System.err.println("command[0]: " + command[0] + " command[1]: " + command[1]);
-                        break;
-                    default:
-                        throw new ErrnoException(ENOEXEC);
-                }
-            } catch(IOException e) {
-                fd.close();
-                throw new ErrnoException(EIO);
-            }
-                        
-            if(command == null) {
-                // its an elf binary
-                try {
-                    s.seek(0);
-                    Class c = RuntimeCompiler.compile(s,"unixruntime");
-                    //System.err.println("Compile succeeded: " + c);
-                    ent = new CacheEnt(mtime,size,c);
-                } catch(Compiler.Exn e) {
-                    if(STDERR_DIAG) e.printStackTrace();
-                    throw new ErrnoException(ENOEXEC);
-                } catch(IOException e) {
-                    if(STDERR_DIAG) e.printStackTrace();
-                    throw new ErrnoException(EIO);
-                }
-            } else {
-                ent = new CacheEnt(mtime,size,command);
-            }
-            
-            fd.close();
-            
-            execCache.put(path,ent);
-            return ent.o;
-        }
     }
     
     public abstract static class FS {
@@ -1260,6 +1312,7 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
         
         char[] in = new char[path.length()+1];
         char[] out = new char[in.length + (absolute ? -1 : cwd.length())];
+        path.getChars(0,path.length(),in,0);
         int inp=0, outp=0;
         
         if(absolute) {
@@ -1269,7 +1322,6 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
             outp = cwdl;
         }
 
-        path.getChars(0,path.length(),in,0);
         while(in[inp] != 0) {
             if(inp != 0) {
                 while(in[inp] != 0 && in[inp] != '/') { out[outp++] = in[inp++]; }
@@ -1297,7 +1349,8 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
         }
         if(outp > 0 && out[outp-1] == '/') outp--;
         //System.err.println("normalize: " + path + " -> " + new String(out,0,outp) + " (cwd: " + cwd + ")");
-        return new String(out,0,outp);
+        int outStart = out[0] == '/' ? 1 : 0;
+        return new String(out,outStart,outp - outStart);
     }
     
     FStat hostFStat(final File f, Object data) {
@@ -1345,6 +1398,29 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
             return f;
         }
         
+        static String reverseMap(String f) {
+            if(f.startsWith("/") && File.separatorChar == '/') return f;
+                
+            Vector vec = new Vector();
+            File root = HostFS.hostRootDir();
+            String s = new File(f).getAbsolutePath();
+            File d = new File(s);
+            System.err.println(s);
+            System.err.println(d);
+            while(!d.equals(root)) {
+                vec.addElement(d.getName());
+                if((s = d.getParent()) == null) break;
+                d = new File(s);
+            }
+            String ret = null;
+            if(s != null) {
+                ret="/";
+                for(int i=vec.size()-1;i>=0;i--) ret += (String) vec.elementAt(i) + (i==0?"":"/");
+            }
+            System.err.println("reverseMap: " + f + " => " + ret);
+            return ret;
+        }
+        
         private File hostFile(String path) {
             char sep = File.separatorChar;
             if(sep != '/') {
@@ -1395,7 +1471,7 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
         
         private static File getParentFile(File f) {
             String p = f.getParent();
-            return p == null ? null : new File(f,p);
+            return p == null ? null : new File(p);
         }
         
         public class HostDirFD extends DirFD {
@@ -1596,5 +1672,55 @@ public abstract class UnixRuntime extends Runtime implements Cloneable {
         
         public void mkdir(UnixRuntime r, String path, int mode) throws ErrnoException { throw new ErrnoException(EROFS); }
         public void unlink(UnixRuntime r, String path) throws ErrnoException { throw new ErrnoException(EROFS); }
-    }    
+    }
+    
+    
+    public static class ResourceFS extends FS {
+        final InodeCache inodes = new InodeCache(500);
+        
+        public FStat lstat(UnixRuntime r, String path) throws ErrnoException { return stat(r,path); }
+        public void mkdir(UnixRuntime r, String path, int mode) throws ErrnoException { throw new ErrnoException(EROFS); }
+        public void unlink(UnixRuntime r, String path) throws ErrnoException { throw new ErrnoException(EROFS); }
+        
+        FStat connFStat(final URLConnection conn) {
+            return new FStat() {
+                public int type() { return S_IFREG; }
+                public int nlink() { return 1; }
+                public int mode() { return 0444; }
+                public int size() { return conn.getContentLength(); }
+                public int mtime() { return (int)(conn.getDate() / 1000); }
+                public int inode() { return inodes.get(conn.getURL().toString()); }
+                public int dev() { return devno; }
+            };
+        }
+        
+        public FStat stat(UnixRuntime r, String path) throws ErrnoException {
+            URL url = r.getClass().getResource("/" + path);
+            if(url == null) return null;
+            try {
+                return connFStat(url.openConnection());
+            } catch(IOException e) {
+                throw new ErrnoException(EIO);
+            }
+        }
+        
+        public FD open(UnixRuntime r, String path, int flags, int mode) throws ErrnoException {
+            if((flags & ~3) != 0) {
+                if(STDERR_DIAG)
+                    System.err.println("WARNING: Unsupported flags passed to ResourceFS.open(\"" + path + "\"): " + toHex(flags & ~3));
+                throw new ErrnoException(ENOTSUP);
+            }
+            if((flags&3) != RD_ONLY) throw new ErrnoException(EROFS);
+            URL url = r.getClass().getResource("/" + path);
+            if(url == null) return null;
+            try {
+                final URLConnection conn = url.openConnection();
+                Seekable.InputStream si = new Seekable.InputStream(conn.getInputStream());
+                return new SeekableFD(si,flags) { protected FStat _fstat() { return connFStat(conn); } };
+            } catch(FileNotFoundException e) {
+                if(e.getMessage() != null && e.getMessage().indexOf("Permission denied") >= 0) throw new ErrnoException(EACCES);
+                return null;
+            } catch(IOException e) { throw new ErrnoException(EIO); }
+        }
+    }
 }