JNI interface returns byte[] instead of String

This allows the output fields of any command to contain nul characters, which
paves the way for extracting a manifest or other binary data directly instead
of having to write it into a temporary file.

commandline.c

@@ -83,20 +83,25 @@ static int outv_growbuf(size_t needed)
 
 static int outv_end_field()
 {
-  outv_growbuf(1);
-  *outv_current++ = '\0';
-  jstring str = (jstring)(*jni_env)->NewStringUTF(jni_env, outv_buffer);
+  size_t length = outv_current - outv_buffer;
   outv_current = outv_buffer;
-  if (str == NULL) {
+  jbyteArray arr = (*jni_env)->NewByteArray(jni_env, length);
+  if (arr == NULL) {
     jni_exception = 1;
-    return WHY("Exception thrown from NewStringUTF()");
+    return WHY("Exception thrown from NewByteArray()");
   }
-  (*jni_env)->CallBooleanMethod(jni_env, outv_list, listAddMethodId, str);
+  (*jni_env)->SetByteArrayRegion(jni_env, arr, 0, length, (jbyte*)outv_buffer);
+  DEBUGF("SetByteArrayRegion(%s)", alloca_toprint(-1, outv_buffer, length));
+  if ((*jni_env)->ExceptionOccurred(jni_env)) {
+    jni_exception = 1;
+    return WHY("Exception thrown from SetByteArrayRegion()");
+  }
+  (*jni_env)->CallBooleanMethod(jni_env, outv_list, listAddMethodId, arr);
   if ((*jni_env)->ExceptionOccurred(jni_env)) {
     jni_exception = 1;
     return WHY("Exception thrown from CallBooleanMethod()");
   }
-  (*jni_env)->DeleteLocalRef(jni_env, str);
+  (*jni_env)->DeleteLocalRef(jni_env, arr);
   return 0;
 }
 
@@ -215,6 +220,32 @@ int cli_putchar(char c)
       return putchar(c);
 }
 
+/* Write a buffer of data to output.  If in a JNI call, then this appends the data to the
+   current output field, including any embedded nul characters.  Returns a non-negative integer on
+   success, EOF on error.
+ */
+int cli_write(const unsigned char *buf, size_t len)
+{
+#ifdef HAVE_JNI_H
+    if (jni_env) {
+      size_t avail = outv_limit - outv_current;
+      if (avail < len) {
+	memcpy(outv_current, buf, avail);
+	outv_current = outv_limit;
+	if (outv_growbuf(len) == -1)
+	  return EOF;
+	len -= avail;
+	buf += avail;
+      }
+      memcpy(outv_current, buf, len);
+      outv_current += len;
+      return 0;
+    }
+    else
+#endif
+      return fwrite(buf, len, 1, stdout);
+}
+
 /* Write a null-terminated string to output.  If in a JNI call, then this appends the string to the
    current output field.  The terminating null is not included.  Returns a non-negative integer on
    success, EOF on error.
@@ -222,21 +253,8 @@ int cli_putchar(char c)
 int cli_puts(const char *str)
 {
 #ifdef HAVE_JNI_H
-    if (jni_env) {
-      size_t len = strlen(str);
-      size_t avail = outv_limit - outv_current;
-      if (avail < len) {
-	strncpy(outv_current, str, avail);
-	outv_current = outv_limit;
-	if (outv_growbuf(len) == -1)
-	  return EOF;
-	len -= avail;
-	str += avail;
-      }
-      strncpy(outv_current, str, len);
-      outv_current += len;
-      return 0;
-    }
+    if (jni_env)
+      return cli_write((const unsigned char *) str, strlen(str));
     else
 #endif
       return fputs(str, stdout);
@@ -307,11 +325,21 @@ void cli_flush()
 int app_echo(int argc, const char *const *argv, struct command_line_option *o, void *context)
 {
   if (debug & DEBUG_VERBOSE) DEBUG_argv("command", argc, argv);
-  int i;
-  for (i = 1; i < argc; ++i) {
+  int i = 1;
+  int escapes = 0;
+  if (i < argc && strcmp(argv[i], "-e") == 0) {
+    escapes = 1;
+    ++i;
+  }
+  for (; i < argc; ++i) {
     if (debug & DEBUG_VERBOSE)
-      DEBUGF("echo:argv[%d]=%s", i, argv[i]);
-    cli_puts(argv[i]);
+      DEBUGF("echo:argv[%d]=\"%s\"", i, argv[i]);
+    if (escapes) {
+      unsigned char buf[strlen(argv[i])];
+      size_t len = str_fromprint(buf, argv[i]);
+      cli_write(buf, len);
+    } else
+      cli_puts(argv[i]);
     cli_delim(NULL);
   }
   return 0;

java/org/servalproject/servald/ServalD.java

@@ -26,18 +26,18 @@ import java.util.LinkedList;
 class ServalD
 {
 	int status;
-	List<String> outv;
+	List<byte[]> outv;
 
 	public ServalD()
 	{
 		System.loadLibrary("servald");
 	}
 
-	public native int rawCommand(List<String> outv, String... args);
+	public native int rawCommand(List<byte[]> outv, String... args);
 
 	public void command(String... args)
 	{
-		this.outv = new LinkedList<String>();
+		this.outv = new LinkedList<byte[]>();
 		this.status = this.rawCommand(this.outv, args);
 	}
 
@@ -45,8 +45,8 @@ class ServalD
 	{
 		ServalD servald = new ServalD();
 		servald.command(args);
-		for (String s: servald.outv) {
-			System.out.println(s);
+		for (byte[] a: servald.outv) {
+			System.out.println(new String(a));
 		}
 		System.exit(servald.status);
 	}

java/org/servalproject/servald/ServalDTests.java

@@ -11,7 +11,7 @@ class ServalDTests
 	public static void main(String[] args)
 	{
 		try {
-			Class cls = new Object() { }.getClass().getEnclosingClass();
+			Class<?> cls = new Object() { }.getClass().getEnclosingClass();
 			Method m = cls.getMethod(args[0], String[].class);
 			m.invoke(null, (Object) Arrays.copyOfRange(args, 1, args.length));
 		}
@@ -29,9 +29,9 @@ class ServalDTests
 		for (int i = 0; i != repeat; ++i) {
 			servald.command(Arrays.copyOfRange(args, 1, args.length));
 			System.out.print(servald.status);
-			for (String s: servald.outv) {
+			for (byte[] a: servald.outv) {
 				System.out.print(":");
-				System.out.print(s);
+				System.out.print(new String(a));
 			}
 			System.out.println("");
 		}

tests/jni

@@ -24,6 +24,7 @@ source "${0%/*}/../testconfig.sh"
 
 setup() {
    setup_servald
+   executeOk_servald config set debug.verbose 1
    assert_echo_works
    compile_java_classes
    setup_servald_so
@@ -32,21 +33,21 @@ setup() {
 compile_java_classes() {
    assert --message='Java compiler was detected by ./configure' [ "$JAVAC" ]
    mkdir classes
-   assert $JAVAC -d classes "$servald_source_root"/java/org/servalproject/servald/*.java
+   assert $JAVAC -Xlint:unchecked -d classes "$servald_source_root"/java/org/servalproject/servald/*.java
    assert [ -r classes/org/servalproject/servald/ServalD.class ]
    assert [ -r classes/org/servalproject/servald/ServalDTests.class ]
 }
 
 # Make sure that the normal echo command-line works, without JNI.
 assert_echo_works() {
-   executeOk $servald echo 'Hello,' 'world!'
-   assertStdoutIs -e 'Hello,\nworld!\n'
+   executeOk $servald echo -e 'Hello,\ttab' 'world\0!'
+   assertStdoutIs -e 'Hello,\ttab\nworld\0!\n'
 }
 
 doc_Echo="Serval JNI echo Hello world"
 test_Echo() {
-   executeOk java -classpath "$PWD/classes" org.servalproject.servald.ServalD echo 'Hello,' 'world!'
-   assertStdoutIs -e 'Hello,\nworld!\n'
+   executeOk java -classpath "$PWD/classes" org.servalproject.servald.ServalD echo -e 'Hello,\ttab' 'world\0!'
+   assertStdoutIs -e 'Hello,\ttab\nworld\0!\n'
 }
 
 doc_Delim="Serval non-JNI output delimiter environment variable"