无法执行script.sh:未知错误 [英] Failed to execute script.sh: unknown error

问题描述

我想使用DTrace来查看"shell脚本进行了哪些系统调用".

I wanted to use DTrace to see "what syscalls are made by my shell script".

我制作了一个非常简单的shell脚本shell.sh，并为其赋予了执行权限:

I made a very simple shell script, shell.sh, and gave it execute privileges:

#!/bin/bash
grep 1 <<< 123

我cd进入其目录，并运行了这个简单的DTrace脚本:

I cd'd into its directory, and ran this simple DTrace script:

sudo dtrace -n 'syscall:::entry
/pid == $target/
{
    @[probefunc] = count();
}' -c ./trace-me.sh

我收到此错误输出:

dtrace: failed to execute ./trace-me.sh: unknown error

这里发生了什么?我已经运行csrutil enable --without dtrace.如果删除-c arg(并用pid替换$target)，则DTrace脚本运行良好.

What happened here? I've run csrutil enable --without dtrace. The DTrace script runs fine if I remove the -c arg (and replace $target with a pid).

这只是另一个Mac陷阱吗?我正在运行macOS Sierra 10.12.5 Beta.

Is this just another Mac gotcha? I'm running macOS Sierra 10.12.5 Beta.

推荐答案

感谢@l'的提示链接:我可以解决此问题.

Thanks to the tip to which @l'L'l linked: I was able to work around this.

您将需要两个外壳.

在外壳A(我们将要检查的外壳)中:

In shell A (the shell we'll be inspecting):

# copy this shell's PID to clipboard (93827 for this example)
echo $$ | pbcopy

在外壳B(将运行DTrace的外壳)中，开始跟踪该PID:

In shell B (the shell which will run DTrace), start tracing that PID:

sudo dtrace -n 'syscall:::entry
/progenyof($1) && pid != $1/
{
    @[probefunc] = count();
}' 93827

我们使用 progenyof() 来确保我们跟踪外壳的子进程.我添加了&& pid != $1，因为出于某些原因，progenyof(x)似乎包含了x.

We use progenyof() to ensure that we trace child processes of the shell. I've added && pid != $1 since for some reason progenyof(x) seems to include x.

现在回到外壳A，运行一些您想检查的代码:

Now back in shell A, run some code you'd like to inspect:

grep 1 <<< 123

我们在外壳B中的DTrace程序将成功捕获在外壳A中启动的子进程.

Our DTrace program in shell B will successfully catch the child process launched in shell A.

有一些噪音需要筛选.也许贝壳发射了各种各样的孩子.不确定如何更具选择性.

There's a bit of noise to sift through. Maybe the shell launches a variety of children. Not sure how to be more selective.

看看dtruss如何实现-f(跟随孩子被分叉")是很有教育意义的.

It's educational to look at how dtruss implements -f ("follow children as they are forked")...

less "$(which dtruss)"

相关子句是使用OPT_follow &&过滤器(表明已启用-f)或self->child变量(表明该线程是-p PID中指定的进程的子代)的子句.

Relevant clauses are those using an OPT_follow && filter (indicates that -f is enabled) or the self->child variable (indicates that this thread is a child of the process specified in -p PID).

知道 ppid 也很有用是一个内置变量，可为您提供父PID.

It's also useful to know that ppid is a built-in variable which gives you the parent PID.

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