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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/PerformanceManager.h>
#include <Kernel/Process.h>
#include <Kernel/VM/Region.h>
namespace Kernel {
KResultOr<pid_t> 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());
auto& child_tss = child_first_thread->m_tss;
child_tss.eax = 0; // fork() returns 0 in the child :^)
child_tss.ebx = regs.ebx;
child_tss.ecx = regs.ecx;
child_tss.edx = regs.edx;
child_tss.ebp = regs.ebp;
child_tss.esp = regs.userspace_esp;
child_tss.esi = regs.esi;
child_tss.edi = regs.edi;
child_tss.eflags = regs.eflags;
child_tss.eip = regs.eip;
child_tss.cs = regs.cs;
child_tss.ds = regs.ds;
child_tss.es = regs.es;
child_tss.fs = regs.fs;
child_tss.gs = regs.gs;
child_tss.ss = regs.userspace_ss;
dbgln_if(FORK_DEBUG, "fork: child will begin executing at {:04x}:{:08x} with stack {:04x}:{:08x}, kstack {:04x}:{:08x}", child_tss.cs, child_tss.eip, child_tss.ss, child_tss.esp, child_tss.ss0, child_tss.esp0);
{
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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