54 lines
1.4 KiB
C++
54 lines
1.4 KiB
C++
/*
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* Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <errno.h>
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#include <sys/ptrace.h>
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#include <syscall.h>
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extern "C" {
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long ptrace(int request, pid_t tid, void* addr, void* data)
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{
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if (request == PT_PEEKBUF) {
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// PT_PEEKBUF cannot easily be correctly used through this function signature:
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// The amount of data to be copied is not available.
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// We could VERIFY() here, but to safeguard against ports that attempt to use
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// the same number, let's claim that the Kernel just doesn't know the command.
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// Use Core::System::ptrace_peekbuf instead.
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return EINVAL;
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}
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// PT_PEEK needs special handling since the syscall wrapper
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// returns the peeked value as an int, which can be negative because of the cast.
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// When using PT_PEEK, the user can check if an error occurred
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// by looking at errno rather than the return value.
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FlatPtr out_data;
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auto is_peek_type = request == PT_PEEK || request == PT_PEEKDEBUG;
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if (is_peek_type) {
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data = &out_data;
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}
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Syscall::SC_ptrace_params params {
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request,
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tid,
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addr,
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(FlatPtr)data
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};
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long rc = syscall(SC_ptrace, ¶ms);
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if (is_peek_type) {
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if (rc < 0) {
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errno = -rc;
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return -1;
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}
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errno = 0;
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return static_cast<long>(out_data);
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}
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__RETURN_WITH_ERRNO(rc, rc, -1);
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}
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}
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