我使用openpty,NSTask和NSTextView来写
a simple terminal.如何实现CtrlC和CtrlD？
我启动一个这样的shell：
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];
然后我截取CtrlC并发送 – [interrupt]到NSTask,如下所示：
- (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];
}
}
但是,中断似乎并没有杀死shell执行的任何程序.如果shell没有子进程,则中断将取消当前输入行.
我不知道如何实现CtrlD.
解决方法
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;
}
