我曾经认为
System.console() != null
是确定启动我的Java应用程序的shell是否具有交互性的可靠方法。这使得我可以在交互模式下使用ANSI escape sequences,只要将程序的输出重定向到文件或通过管道传输到某个其他进程的标准输入,就可以使用普通System.out
/ System.err
,类似于{{3许多GNU实用程序的模式。
System.console()
行为在 Windows 中有所不同。当从null
启动JVM时,方法返回非cmd.exe
值(这对我来说没用,因为cmd.exe
无法理解转义序列),当我从 Cygwin 中可用的任何终端模拟器启动我的程序时,返回值总是 null
,xterm
,{ {1}}或mintty
(最后一个仅仅是运行cygwin
子进程的cmd.exe
。
如何在Java中测试交互式shell,无需在shell脚本中读取bash
并将命令行参数传递给我的Java程序?从Java中测试$-
环境变量不是一个选项,因为Java是从shell脚本启动的,因此父进程是非交互式shell,并且PS1
未设置。
答案 0 :(得分:2)
有一个conversation Cygwin的维护者(Corinna Vinschen)解释说Cygwin伪TTY看起来像是Microsoft Visual C运行时库(MSVCRT)的管道。她还建议在isatty()
函数周围实现一个包装器来识别Cygwin伪TTY。
想法是获取与给定文件描述符关联的管道的名称。 NtQueryInformationFile
函数提取FILE_NAME_INFORMATION
结构,其中FileName
成员包含管道名称。如果管道名称与以下模式匹配,则命令很可能以交互模式运行:
\cygwin-%16llx-pty%d-{to,from}-master
对话很旧,但管道名称的格式仍然相同:
"\\\\.\\pipe\\cygwin-" + "%S-" +
+ "pty%d-from-master"
,其中"\\\\.\\pipe\\"
是命名管道的对应前缀(请参阅CreateNamedPipe
)。
所以Cygwin部分已经被黑了。下一步是从C代码创建Java函数。
以下创建ttyjni.TestApp
类,其中istty()
方法通过Java Native Interface(JNI)实现。代码在GNU / Linux(x86_64
)和Windows 7(64位)上的Cygwin上进行测试。代码可以轻松移植到Windows(cmd.exe
),甚至可以按原样运行。
必需的组件
x86_64-w64-mingw32-gcc
编译器<强>布局强>
├── Makefile
├── TestApp.c
├── test.sh
├── ttyjni
│ └── TestApp.java
└── ttyjni_TestApp.h
<强>生成文件强>
# Input: $JAVA_HOME
FINAL_TARGETS := TestApp.class
ifeq ($(OS),Windows_NT)
CC=x86_64-w64-mingw32-gcc
FINAL_TARGETS += testapp.dll
else
CC=gcc
FINAL_TARGETS += libtestapp.so
endif
all: $(FINAL_TARGETS)
TestApp.class: ttyjni/TestApp.java
javac $<
testapp.dll: TestApp.c TestApp.class
$(CC) \
-Wl,--add-stdcall-alias \
-D__int64="long long" \
-D_isatty=isatty -D_fileno=fileno \
-I"$(JAVA_HOME)/include" \
-I"$(JAVA_HOME)/include/win32" \
-shared -o $@ $<
libtestapp.so: TestApp.c
$(CC) \
-I"$(JAVA_HOME)/include" \
-I"$(JAVA_HOME)/include/linux" \
-fPIC \
-o $@ -shared -Wl,-soname,testapp.so $< \
-z noexecstack
clean:
rm -f *.o $(FINAL_TARGETS) ttyjni/*.class
<强> TestApp.c 强>
#include <jni.h>
#include <stdio.h>
#include "ttyjni_TestApp.h"
#if defined __CYGWIN__ || defined __MINGW32__ || defined __MINGW64__
#include <io.h>
#include <errno.h>
#include <wchar.h>
#include <windows.h>
#include <winternl.h>
#include <unistd.h>
/* vvvvvvvvvv From http://cygwin.com/ml/cygwin/2012-11/txt00003.txt vvvvvvvv */
#ifndef __MINGW64_VERSION_MAJOR
/* MS winternl.h defines FILE_INFORMATION_CLASS, but with only a
different single member. */
enum FILE_INFORMATION_CLASSX
{
FileNameInformation = 9
};
typedef struct _FILE_NAME_INFORMATION
{
ULONG FileNameLength;
WCHAR FileName[1];
} FILE_NAME_INFORMATION, *PFILE_NAME_INFORMATION;
NTSTATUS (NTAPI *pNtQueryInformationFile) (HANDLE, PIO_STATUS_BLOCK, PVOID,
ULONG, FILE_INFORMATION_CLASSX);
#else
NTSTATUS (NTAPI *pNtQueryInformationFile) (HANDLE, PIO_STATUS_BLOCK, PVOID,
ULONG, FILE_INFORMATION_CLASS);
#endif
jint
testapp_isatty(jint fd)
{
HANDLE fh;
NTSTATUS status;
IO_STATUS_BLOCK io;
long buf[66]; /* NAME_MAX + 1 + sizeof ULONG */
PFILE_NAME_INFORMATION pfni = (PFILE_NAME_INFORMATION) buf;
PWCHAR cp;
/* First check using _isatty.
Note that this returns the wrong result for NUL, for instance!
Workaround is not to use _isatty at all, but rather GetFileType
plus object name checking. */
if (_isatty(fd))
return 1;
/* Now fetch the underlying HANDLE. */
fh = (HANDLE)_get_osfhandle(fd);
if (!fh || fh == INVALID_HANDLE_VALUE) {
errno = EBADF;
return 0;
}
/* Must be a pipe. */
if (GetFileType (fh) != FILE_TYPE_PIPE)
goto no_tty;
/* Calling the native NT function NtQueryInformationFile is required to
support pre-Vista systems. If that's of no concern, Vista introduced
the GetFileInformationByHandleEx call with the FileNameInfo info class,
which can be used instead. */
if (!pNtQueryInformationFile) {
pNtQueryInformationFile = (NTSTATUS (NTAPI *)(HANDLE, PIO_STATUS_BLOCK,
PVOID, ULONG, FILE_INFORMATION_CLASS))
GetProcAddress(GetModuleHandle("ntdll.dll"), "NtQueryInformationFile");
if (!pNtQueryInformationFile)
goto no_tty;
}
if (!NT_SUCCESS (pNtQueryInformationFile (fh, &io, pfni, sizeof buf,
FileNameInformation)))
goto no_tty;
/* The filename is not guaranteed to be NUL-terminated. */
pfni->FileName[pfni->FileNameLength / sizeof (WCHAR)] = L'\0';
/* Now check the name pattern. The filename of a Cygwin pseudo tty pipe
looks like this:
\cygwin-%16llx-pty%d-{to,from}-master
%16llx is the hash of the Cygwin installation, (to support multiple
parallel installations), %d id the pseudo tty number, "to" or "from"
differs the pipe direction. "from" is a stdin, "to" a stdout-like
pipe. */
cp = pfni->FileName;
if (!wcsncmp(cp, L"\\cygwin-", 8)
&& !wcsncmp (cp + 24, L"-pty", 4))
{
cp = wcschr(cp + 28, '-');
if (!cp)
goto no_tty;
if (!wcscmp (cp, L"-from-master") || !wcscmp (cp, L"-to-master"))
return 1;
}
no_tty:
errno = EINVAL;
return 0;
}
/* ^^^^^^^^^^ From http://cygwin.com/ml/cygwin/2012-11/txt00003.txt ^^^^^^^^ */
#elif _WIN32
#include <io.h>
static jint
testapp_isatty(jint fd)
{
return _isatty(fd);
}
#elif defined __linux__ || defined __sun || defined __FreeBSD__
#include <unistd.h>
static jint
testapp_isatty(jint fd)
{
return isatty(fd);
}
#else
#error Unsupported platform
#endif /* __CYGWIN__ */
JNIEXPORT jboolean JNICALL Java_ttyjni_TestApp_istty
(JNIEnv *env, jobject obj)
{
return testapp_isatty(fileno(stdin)) &&
testapp_isatty(fileno(stdout)) ?
JNI_TRUE : JNI_FALSE;
}
<强> ttyjni_TestApp.h
强>
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class ttyjni_TestApp */
#ifndef _Included_ttyjni_TestApp
#define _Included_ttyjni_TestApp
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: ttyjni_TestApp
* Method: istty
* Signature: ()Z
*/
JNIEXPORT jboolean JNICALL Java_ttyjni_TestApp_istty
(JNIEnv *, jobject);
#ifdef __cplusplus
}
#endif
#endif
<强> ttyjni / TestApp.java 强>
package ttyjni;
import java.io.Console;
import java.lang.reflect.Method;
class TestApp {
static {
System.loadLibrary("testapp");
}
private native boolean istty();
private static final String ISTTY_METHOD = "istty";
private static final String INTERACTIVE = "interactive";
private static final String NON_INTERACTIVE = "non-interactive";
protected static boolean isInteractive() {
try {
Method method = Console.class.getDeclaredMethod(ISTTY_METHOD);
method.setAccessible(true);
return (Boolean) method.invoke(Console.class);
} catch (Exception e) {
System.out.println(e.toString());
}
return false;
}
public static void main(String[] args) {
// Testing JNI
TestApp t = new TestApp();
boolean b = t.istty();
System.out.format("%s(jni)\n", b ?
"interactive" : "non-interactive");
// Testing pure Java
System.out.format("%s(console)\n", System.console() != null ?
INTERACTIVE : NON_INTERACTIVE);
System.out.format("%s(java)\n", isInteractive() ?
INTERACTIVE : NON_INTERACTIVE);
}
}
<强> test.sh 强>
#!/bin/bash -
java -Djava.library.path="$(dirname "$0")" ttyjni.TestApp
<强>编译强>
make
在Linux上测试
$ ./test.sh
interactive(jni)
interactive(console)
interactive(java)
$ ./test.sh > 1
ruslan@pavilion ~/tmp/java $ cat 1
non-interactive(jni)
non-interactive(console)
non-interactive(java)
在Cygwin上进行测试
$ ./test.sh
interactive(jni)
non-interactive(console)
non-interactive(java)
$ ./test.sh > 1
$ cat 1
non-interactive(jni)
non-interactive(console)
non-interactive(java)