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- /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #include <Kernel/Debug.h>
- #include <Kernel/FileSystem/Custody.h>
- #include <Kernel/FileSystem/FileDescription.h>
- #include <Kernel/Panic.h>
- #include <Kernel/PerformanceManager.h>
- #include <Kernel/Process.h>
- #include <Kernel/VM/Region.h>
- namespace Kernel {
- KResultOr<FlatPtr> Process::sys$fork(RegisterState& regs)
- {
- REQUIRE_PROMISE(proc);
- RefPtr<Thread> child_first_thread;
- auto child = Process::create(child_first_thread, m_name, uid(), gid(), pid(), m_is_kernel_process, m_cwd, m_executable, m_tty, this);
- if (!child || !child_first_thread)
- return ENOMEM;
- child->m_root_directory = m_root_directory;
- child->m_root_directory_relative_to_global_root = m_root_directory_relative_to_global_root;
- child->m_veil_state = m_veil_state;
- child->m_unveiled_paths = m_unveiled_paths.deep_copy();
- child->m_fds = m_fds;
- child->m_pg = m_pg;
- {
- ProtectedDataMutationScope scope { *child };
- child->m_promises = m_promises;
- child->m_execpromises = m_execpromises;
- child->m_has_promises = m_has_promises;
- child->m_has_execpromises = m_has_execpromises;
- child->m_sid = m_sid;
- child->m_extra_gids = m_extra_gids;
- child->m_umask = m_umask;
- child->m_signal_trampoline = m_signal_trampoline;
- child->m_dumpable = m_dumpable;
- }
- dbgln_if(FORK_DEBUG, "fork: child={}", child);
- child->space().set_enforces_syscall_regions(space().enforces_syscall_regions());
- #if ARCH(I386)
- auto& child_regs = child_first_thread->m_regs;
- child_regs.eax = 0; // fork() returns 0 in the child :^)
- child_regs.ebx = regs.ebx;
- child_regs.ecx = regs.ecx;
- child_regs.edx = regs.edx;
- child_regs.ebp = regs.ebp;
- child_regs.esp = regs.userspace_esp;
- child_regs.esi = regs.esi;
- child_regs.edi = regs.edi;
- child_regs.eflags = regs.eflags;
- child_regs.eip = regs.eip;
- child_regs.cs = regs.cs;
- child_regs.ds = regs.ds;
- child_regs.es = regs.es;
- child_regs.fs = regs.fs;
- child_regs.gs = regs.gs;
- child_regs.ss = regs.userspace_ss;
- dbgln_if(FORK_DEBUG, "fork: child will begin executing at {:04x}:{:08x} with stack {:04x}:{:08x}, kstack {:04x}:{:08x}",
- child_regs.cs, child_regs.eip, child_regs.ss, child_regs.esp, child_regs.ss0, child_regs.esp0);
- #else
- (void)regs;
- PANIC("Process::sys$fork() not implemented.");
- #endif
- {
- ScopedSpinLock lock(space().get_lock());
- for (auto& region : space().regions()) {
- dbgln_if(FORK_DEBUG, "fork: cloning Region({}) '{}' @ {}", region, region->name(), region->vaddr());
- auto region_clone = region->clone(*child);
- if (!region_clone) {
- dbgln("fork: Cannot clone region, insufficient memory");
- // TODO: tear down new process?
- return ENOMEM;
- }
- auto& child_region = child->space().add_region(region_clone.release_nonnull());
- child_region.map(child->space().page_directory(), ShouldFlushTLB::No);
- if (region == m_master_tls_region.unsafe_ptr())
- child->m_master_tls_region = child_region;
- }
- ScopedSpinLock processes_lock(g_processes_lock);
- g_processes->prepend(*child);
- }
- PerformanceManager::add_process_created_event(*child);
- ScopedSpinLock lock(g_scheduler_lock);
- child_first_thread->set_affinity(Thread::current()->affinity());
- child_first_thread->set_state(Thread::State::Runnable);
- auto child_pid = child->pid().value();
- // We need to leak one reference so we don't destroy the Process,
- // which will be dropped by Process::reap
- (void)child.leak_ref();
- return child_pid;
- }
- }
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