serenity/Kernel/Syscalls/fork.cpp

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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
Meta: Split debug defines into multiple headers. The following script was used to make these changes: #!/bin/bash set -e tmp=$(mktemp -d) echo "tmp=$tmp" find Kernel \( -name '*.cpp' -o -name '*.h' \) | sort > $tmp/Kernel.files find . \( -path ./Toolchain -prune -o -path ./Build -prune -o -path ./Kernel -prune \) -o \( -name '*.cpp' -o -name '*.h' \) -print | sort > $tmp/EverythingExceptKernel.files cat $tmp/Kernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/Kernel.macros cat $tmp/EverythingExceptKernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/EverythingExceptKernel.macros comm -23 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/Kernel.unique comm -1 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/EverythingExceptKernel.unique cat $tmp/Kernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/Kernel.header cat $tmp/EverythingExceptKernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/EverythingExceptKernel.header for macro in $(cat $tmp/Kernel.unique) do cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.new-includes ||: done cat $tmp/Kernel.new-includes | sort > $tmp/Kernel.new-includes.sorted for macro in $(cat $tmp/EverythingExceptKernel.unique) do cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.old-includes ||: done cat $tmp/Kernel.old-includes | sort > $tmp/Kernel.old-includes.sorted comm -23 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.new comm -13 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.old comm -12 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.mixed for file in $(cat $tmp/Kernel.includes.new) do sed -i -E 's/#include <AK\/Debug\.h>/#include <Kernel\/Debug\.h>/' $file done for file in $(cat $tmp/Kernel.includes.mixed) do echo "mixed include in $file, requires manual editing." done
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#include <Kernel/Debug.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Panic.h>
#include <Kernel/PerformanceManager.h>
#include <Kernel/Process.h>
#include <Kernel/VM/Region.h>
namespace Kernel {
KResultOr<FlatPtr> Process::sys$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
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auto& child_regs = child_first_thread->m_regs;
child_regs.rax = 0; // fork() returns 0 in the child :^)
child_regs.rbx = regs.rbx;
child_regs.rcx = regs.rcx;
child_regs.rdx = regs.rdx;
child_regs.rbp = regs.rbp;
child_regs.rsp = regs.userspace_rsp;
child_regs.rsi = regs.rsi;
child_regs.rdi = regs.rdi;
child_regs.r8 = regs.r8;
child_regs.r9 = regs.r9;
child_regs.r10 = regs.r10;
child_regs.r11 = regs.r11;
child_regs.r12 = regs.r12;
child_regs.r13 = regs.r13;
child_regs.r14 = regs.r14;
child_regs.r15 = regs.r15;
child_regs.rflags = regs.rflags;
child_regs.rip = regs.rip;
child_regs.cs = regs.cs;
dbgln_if(FORK_DEBUG, "fork: child will begin executing at {:04x}:{:16x} with stack {:08x}, kstack {:08x}",
child_regs.cs, child_regs.rip, child_regs.rsp, child_regs.rsp0);
#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;
}
}