bb6eb0f6ea
This patch adds the ability to call 'kill' with the own PID to trigger the execution of the handler of the specified POSIX signal. This is used by 'bash', e.g., when cancelling the input of a command via control-c. Related to issue #3546
118 lines
2.2 KiB
C++
118 lines
2.2 KiB
C++
/*
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* \brief POSIX signal handling
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* \author Norman Feske
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* \date 2019-10-11
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*/
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/*
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* Copyright (C) 2019 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _LIBC__INTERNAL__SIGNAL_H_
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#define _LIBC__INTERNAL__SIGNAL_H_
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/* Genode includes */
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#include <util/noncopyable.h>
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#include <base/registry.h>
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/* libc includes */
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#include <signal.h>
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/* libc-internal includes */
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#include <internal/types.h>
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namespace Libc { struct Signal; }
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struct Libc::Signal : Noncopyable
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{
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public:
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struct sigaction signal_action[NSIG + 1] { };
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private:
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struct Pending
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{
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virtual ~Pending() { }
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unsigned const n;
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Pending(unsigned n) : n(n) { }
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};
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Constructible<Registered<Pending>> _charged_signals[NSIG + 1];
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Registry<Registered<Pending>> _pending_signals { };
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void _execute_signal_handler(unsigned n);
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unsigned _count = 0;
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bool _exit = false;
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unsigned _exit_code = 0;
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unsigned _nesting_level = 0;
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pid_t const _local_pid;
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public:
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Signal(pid_t local_pid) : _local_pid(local_pid) { }
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void charge(unsigned n)
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{
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if (n > NSIG)
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return;
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_charged_signals[n].construct(_pending_signals, n);
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_count++;
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}
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void execute_signal_handlers()
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{
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/*
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* Prevent nested execution of signal handlers, which may happen
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* if I/O operations are executed by a signal handler.
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*/
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if (_nesting_level > 0) {
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warning("attempt to nested execution of signal handlers");
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return;
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}
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_nesting_level++;
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_pending_signals.for_each([&] (Pending &pending) {
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_execute_signal_handler(pending.n);
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_charged_signals[pending.n].destruct();
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});
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_nesting_level--;
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/*
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* Exit application due to a signal such as SIGINT.
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*/
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if (_exit)
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exit(_exit_code);
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}
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/**
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* Return number of triggered signals
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*
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* The value is intended to be used for tracking whether a signal
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* occurred during a blocking operation ('select').
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*/
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unsigned count() const { return _count; }
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/**
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* Return true if specified PID belongs to the process itself
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*/
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bool local_pid(pid_t pid) const { return pid == _local_pid; }
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};
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#endif /* _LIBC__INTERNAL__SIGNAL_H_ */
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