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54161bf5b4
Previously, we would try to acquire a reference to the all processes lock or other contended resources while holding both the scheduler lock and the thread's blocker lock. This could lead to a deadlock if we actually have to block on those other resources.
67 lines
2 KiB
C++
67 lines
2 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Variant.h>
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#include <Kernel/Debug.h>
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#include <Kernel/Process.h>
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namespace Kernel {
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KResultOr<siginfo_t> Process::do_waitid(Variant<Empty, NonnullRefPtr<Process>, NonnullRefPtr<ProcessGroup>> waitee, int options)
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{
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KResultOr<siginfo_t> result = KResult(KSuccess);
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if (Thread::current()->block<Thread::WaitBlocker>({}, options, move(waitee), result).was_interrupted())
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return EINTR;
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VERIFY(!result.is_error() || (options & WNOHANG) || result.error() != KSuccess);
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return result;
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}
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KResultOr<FlatPtr> Process::sys$waitid(Userspace<const Syscall::SC_waitid_params*> user_params)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
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REQUIRE_PROMISE(proc);
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Syscall::SC_waitid_params params;
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if (!copy_from_user(¶ms, user_params))
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return EFAULT;
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Variant<Empty, NonnullRefPtr<Process>, NonnullRefPtr<ProcessGroup>> waitee = Empty {};
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switch (params.idtype) {
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case P_ALL:
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waitee = Empty {};
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break;
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case P_PID: {
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auto waitee_process = Process::from_pid(params.id);
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if (!waitee_process || waitee_process->ppid() != Process::current().pid()) {
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return ECHILD;
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}
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waitee = waitee_process.release_nonnull();
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break;
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}
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case P_PGID: {
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auto waitee_group = ProcessGroup::from_pgid(params.id);
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if (!waitee_group) {
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return ECHILD;
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}
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waitee = waitee_group.release_nonnull();
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break;
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}
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default:
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return EINVAL;
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}
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dbgln_if(PROCESS_DEBUG, "sys$waitid({}, {}, {}, {})", params.idtype, params.id, params.infop, params.options);
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auto siginfo_or_error = do_waitid(move(waitee), params.options);
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if (siginfo_or_error.is_error())
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return siginfo_or_error.error();
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if (!copy_to_user(params.infop, &siginfo_or_error.value()))
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return EFAULT;
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return 0;
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}
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}
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