Danny Robson
c15794d4b3
PTRACE_ME doesn't work as we thought, instead just deliver a suitable signal depending on if we're currently under a debugger.
119 lines
2.7 KiB
C++
119 lines
2.7 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright:
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* 2011-2016, Danny Robson <danny@nerdcruft.net>
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*/
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#include "./debug.hpp"
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#include "./log.hpp"
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#include <unistd.h>
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#include <sys/ptrace.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <signal.h>
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///////////////////////////////////////////////////////////////////////////////
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// Will return true if it is known we are under a debugger. This isn't
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// designed to exhaustively check for debuggers, only to offer conveniences.
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// Specifically: errors will return false.
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static
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bool
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is_debugged (void)
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{
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auto pid = fork ();
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if (pid == -1)
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return false;
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// We are the child
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if (pid == 0) {
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auto ppid = getppid ();
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int res;
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// attempt to trace our parent. this will fail if we're being debugged.
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if (ptrace (PTRACE_ATTACH, ppid, nullptr, nullptr) == 0) {
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waitpid (ppid, nullptr, 0);
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ptrace (PTRACE_DETACH, ppid, nullptr, nullptr);
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res = 0;
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} else {
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res = 1;
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}
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_exit (res);
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// We are the parent. Wait for our child to tell us the result.
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} else {
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int status;
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waitpid (pid, &status, 0);
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return WEXITSTATUS (status);
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}
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}
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///////////////////////////////////////////////////////////////////////////////
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void
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breakpoint (void)
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{
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raise (SIGTRAP);
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}
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///////////////////////////////////////////////////////////////////////////////
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void
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prepare_debugger (void)
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{
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;
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}
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//-----------------------------------------------------------------------------
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void
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await_debugger (void)
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{
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if (is_debugged ())
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breakpoint ();
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else
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raise (SIGSTOP);
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}
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///////////////////////////////////////////////////////////////////////////////
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#include <fenv.h>
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void
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enable_fpe (void)
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{
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feenableexcept (FE_DIVBYZERO | FE_INVALID);
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}
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//-----------------------------------------------------------------------------
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void
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disable_fpe (void)
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{
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feenableexcept (0);
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}
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///////////////////////////////////////////////////////////////////////////////
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void
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force_console (void)
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{
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if (!isatty (fileno (stdout))) {
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LOG_ERROR ("expected debugging under a console");
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}
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}
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