杀死一个Haskell二进制文件 [英] Killing a Haskell binary

问题描述

如果我按Ctrl + C，这会引发异常（总是在线程0中？）。如果你愿意，你可以抓住这个 - 或者更可能的是，运行一些清理工作然后重新抛出它。但通常的结果是让程序停顿，这种或那种方式。

现在假设我使用Unix kill 命令。据我所知， kill 基本上发送一个（可配置的）Unix信号给指定的进程。

Haskell RTS对此作出回应？它是否记录在某处？我想 发送 SIGTERM 与Ctrl + C具有相同的效果，但我不知道这个事实...

（当然，您可以使用 kill 发送与根本无关的信号。再一次，我会想象 RTS会忽略，例如 SIGHUP 或 SIGPWR ，但我不确定。）

解决方案

在 ghc源代码在github上透露了 installDefaultSignals 函数：

  void 
 initDefaultHandlers（void）
 {
 struct sigaction动作，oact; 
 
 //安装SIGINT处理程序
 action.sa_handler = shutdown_handler; 
 sigemptyset（& action.sa_mask）; 
 action.sa_flags = 0;如果（sigaction（SIGINT，& action，& oact）！= 0）{
 sysErrorBelch（警告：未能安装SIGINT处理程序），
; 
} 
 
 #if defined（HAVE_SIGINTERRUPT）
 siginterrupt（SIGINT，1）; //是不是默认的？ --SDM 
 #endif 
 
 //安装SIGFPE处理程序
 
 //除了处理SIGINT外，还可以通过忽略它来处理SIGFPE。 
 //显然IEEE要求浮点异常被
 //默认值忽略，但alpha-dec-osf3似乎没有这样做。 
 
 // SDM注释2/7/2002：这会导致
 // //当一个整数除零时发生无限循环：// 
 // don不会从浮点异常中恢复，并且
 //程序会立即生成另一个。 
 #if 0 
 action.sa_handler = SIG_IGN; 
 sigemptyset（& action.sa_mask）; 
 action.sa_flags = 0;如果（sigaction（SIGFPE，& action，& oact）！= 0）{
 sysErrorBelch（警告：未能安装SIGFPE处理程序），
; 
} 
 #endif 
 
 #ifdef alpha_HOST_ARCH 
 ieee_set_fp_control（0）; 
 #endif 
 
 //忽略SIGPIPE;请参阅＃1619 
 //实际上，我们使用空信号处理程序而不是SIG_IGN，
 //以便SIGPIPE在exec处重置为默认行为。 
 action.sa_handler = empty_handler; 
 sigemptyset（& action.sa_mask）; 
 action.sa_flags = 0;如果（sigaction（SIGPIPE，& action，& oact）！= 0）{
 sysErrorBelch（warning：未能安装SIGPIPE处理程序），
; 
} 
 
 set_sigtstp_action（rtsTrue）; 
} 
  

从中可以看到GHC至少安装了SIGINT和SIGPIPE处理程序。我不知道是否有任何其他信号处理程序隐藏在源代码中。

If I press Ctrl+C, this throws an exception (always in thread 0?). You can catch this if you want - or, more likely, run some cleanup and then rethrow it. But the usual result is to bring the program to a halt, one way or another.

Now suppose I use the Unix kill command. As I understand it, kill basically sends a (configurable) Unix signal to the specified process.

How does the Haskell RTS respond to this? Is it documented somewhere? I would imagine that sending SIGTERM would have the same effect as pressing Ctrl+C, but I don't know that for a fact...

(And, of course, you can use kill to send signals that have nothing to do with killing at all. Again, I would imagine that the RTS would ignore, say, SIGHUP or SIGPWR, but I don't know for sure.)

解决方案

Searching for "signal" in the ghc source code on github revealed the installDefaultSignals function:

void
initDefaultHandlers(void)
{
    struct sigaction action,oact;

    // install the SIGINT handler
    action.sa_handler = shutdown_handler;
    sigemptyset(&action.sa_mask);
    action.sa_flags = 0;
    if (sigaction(SIGINT, &action, &oact) != 0) {
sysErrorBelch("warning: failed to install SIGINT handler");
    }

#if defined(HAVE_SIGINTERRUPT)
    siginterrupt(SIGINT, 1);    // isn't this the default? --SDM
#endif

    // install the SIGFPE handler

    // In addition to handling SIGINT, also handle SIGFPE by ignoring it.
    // Apparently IEEE requires floating-point exceptions to be ignored by
    // default, but alpha-dec-osf3 doesn't seem to do so.

    // Commented out by SDM 2/7/2002: this causes an infinite loop on
    // some architectures when an integer division by zero occurs: we
    // don't recover from the floating point exception, and the
    // program just generates another one immediately.
#if 0
    action.sa_handler = SIG_IGN;
    sigemptyset(&action.sa_mask);
    action.sa_flags = 0;
    if (sigaction(SIGFPE, &action, &oact) != 0) {
    sysErrorBelch("warning: failed to install SIGFPE handler");
}
#endif

#ifdef alpha_HOST_ARCH
    ieee_set_fp_control(0);
#endif

    // ignore SIGPIPE; see #1619
    // actually, we use an empty signal handler rather than SIG_IGN,
    // so that SIGPIPE gets reset to its default behaviour on exec.
    action.sa_handler = empty_handler;
    sigemptyset(&action.sa_mask);
    action.sa_flags = 0;
    if (sigaction(SIGPIPE, &action, &oact) != 0) {
sysErrorBelch("warning: failed to install SIGPIPE handler");
    }

    set_sigtstp_action(rtsTrue);
}

From that, you can see that GHC installs at least SIGINT and SIGPIPE handlers. I don't know if there are any other signal handlers hidden in the source code.

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