objective-c – 如何用空白实现Ctrl-C和Ctrl-D？

int amaster = 0,aslave = 0;
if (openpty(&amaster,&aslave,NULL,NULL) == -1) {
    NSLog(@"openpty Failed");
    return;
}

masterHandle = [[NSFileHandle alloc] initWithFileDescriptor:amaster cloSEOnDealloc:YES];
NSFileHandle *slaveHandle = [[NSFileHandle alloc] initWithFileDescriptor:aslave cloSEOnDealloc:YES];

NSTask *task = [NSTask new];
task.launchPath = @"/bin/bash";
task.arguments = @[@"-i",@"-l"];
task.standardInput = slaveHandle;
task.standardOutput = slaveHandle;
task.standardError = errorOutputPipe = [NSPipe pipe];
[task launch];

- (void)keyDown:(NSEvent *)theEvent
{
    NSUInteger flags = theEvent.modifierFlags;
    unsigned short keyCode = theEvent.keyCode;

    if ((flags & NSControlKeyMask) && keyCode == 8) { // ctrl-c
        [task interrupt]; // ???
    } else if ((flags & NSControlKeyMask) && keyCode == 2) { // ctrl-d
        // ???
    } else {
        [super keyDown:theEvent];
    }
}

我也在俄罗斯可可开发商Slack频道中询问了这个问题,并从 Dmitry Rodionov收到了答案.他用这个要点： ctrlc-ptty-nstask.markdown用俄语回答,并给予我批准在这里发布英文版本.

他的实现是基于Pokey McPokerson建议的,但更直接：他使用Technical Q&A QA1123
Getting List of All Processes on Mac OS X中的GetBSDProcessList()获取子进程的列表,并向其中的每个发送SIGINT：

kinfo_proc *procs = NULL;
size_t count;
if (0 != GetBSDProcessList(&procs,&count)) {
    return;
}
BOOL hasChildren = NO;
for (size_t i = 0; i < count; i++) {
    // If the process if a child of our bash process we send SIGINT to it
    if (procs[i].kp_eproc.e_ppid == task.processIdentifier) {
        hasChildren = YES;

        kill(procs[i].kp_proc.p_pid,SIGINT);
    }
}
free(procs);

如果一个进程没有子进程,他会直接向该进程发送SIGINT：

if (hasChildren == NO) {
    kill(task.processIdentifier,SIGINT);
}

这种方法是完美的,但有两个可能的问题(我本人不在乎我正在写我自己的玩具终端)：

>每次按Ctrl-C时,通过所有进程枚举是非常详尽的.也许有更好的方法来找到子进程.
>我和Dmitriy我们都不确定是否杀死所有的子进程是Ctrl-C在真实终端中工作的方式.

下面是Dmitriy的完整版本代码：

- (void)keyDown:(NSEvent *)theEvent
{
    NSUInteger flags = theEvent.modifierFlags;
    unsigned short keyCode = theEvent.keyCode;

    if ((flags & NSControlKeyMask) && keyCode == 8) {

        [self sendCtrlC];

    } else if ((flags & NSControlKeyMask) && keyCode == 2) {
        [masterHandle writeData:[NSData dataWithBytes: "\004" length:1]];
    } else if ((flags & NSDeviceIndependentModifierFlagsMask) == 0 && keyCode == 126) {
        NSLog(@"up");
    } else if ((flags & NSDeviceIndependentModifierFlagsMask) == 0 && keyCode == 125) {
        NSLog(@"down");
    } else {
        [super keyDown:theEvent];
    }
}

// #include <sys/sysctl.h>
// typedef struct kinfo_proc kinfo_proc;

- (void)sendCtrlC
{
    [masterHandle writeData:[NSData dataWithBytes: "\003" length:1]];

    kinfo_proc *procs = NULL;
    size_t count;
    if (0 != GetBSDProcessList(&procs,&count)) {
        return;
    }
    BOOL hasChildren = NO;
    for (size_t i = 0; i < count; i++) {
        if (procs[i].kp_eproc.e_ppid == task.processIdentifier) {
            hasChildren = YES;
            kill(procs[i].kp_proc.p_pid,SIGINT);
        }
    }
    free(procs);

    if (hasChildren == NO) {
        kill(task.processIdentifier,SIGINT);
    }
}

static int GetBSDProcessList(kinfo_proc **procList,size_t *procCount)
// Returns a list of all BSD processes on the system.  This routine
// allocates the list and puts it in *procList and a count of the
// number of entries in *procCount.  You are responsible for freeing
// this list (use "free" from System framework).
// On success,the function returns 0.
// On error,the function returns a BSD errno value.
{
    int                 err;
    kinfo_proc *        result;
    bool                done;
    static const int    name[] = { CTL_KERN,KERN_PROC,KERN_PROC_ALL,0 };
    // Declaring name as const requires us to cast it when passing it to
    // sysctl because the prototype doesn't include the const modifier.
    size_t              length;

    assert( procList != NULL);
    assert(*procList == NULL);
    assert(procCount != NULL);

    *procCount = 0;

    // We start by calling sysctl with result == NULL and length == 0.
    // That will succeed,and set length to the appropriate length.
    // We then allocate a buffer of that size and call sysctl again
    // with that buffer.  If that succeeds,we're done.  If that fails
    // with ENOMEM,we have to throw away our buffer and loop.  Note
    // that the loop causes use to call sysctl with NULL again; this
    // is necessary because the ENOMEM failure case sets length to
    // the amount of data returned,not the amount of data that
    // Could have been returned.

    result = NULL;
    done = false;
    do {
        assert(result == NULL);

        // Call sysctl with a NULL buffer.

        length = 0;
        err = sysctl( (int *) name,(sizeof(name) / sizeof(*name)) - 1,&length,0);
        if (err == -1) {
            err = errno;
        }

        // Allocate an appropriately sized buffer based on the results
        // from the prevIoUs call.

        if (err == 0) {
            result = malloc(length);
            if (result == NULL) {
                err = ENOMEM;
            }
        }

        // Call sysctl again with the new buffer.  If we get an ENOMEM
        // error,toss away our buffer and start again.

        if (err == 0) {
            err = sysctl( (int *) name,result,0);
            if (err == -1) {
                err = errno;
            }
            if (err == 0) {
                done = true;
            } else if (err == ENOMEM) {
                assert(result != NULL);
                free(result);
                result = NULL;
                err = 0;
            }
        }
    } while (err == 0 && ! done);

    // Clean up and establish post conditions.

    if (err != 0 && result != NULL) {
        free(result);
        result = NULL;
    }
    *procList = result;
    if (err == 0) {
        *procCount = length / sizeof(kinfo_proc);
    }
    assert( (err == 0) == (*procList != NULL) );
    return err;
}