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https://github.com/LadybirdBrowser/ladybird.git
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a89648e159
We need to create a reference for the new PID for each shared buffer that the process had a reference to. If the process subsequently get replaced through exec, those references will be dropped again. But if exec for some reason fails then other code, such as global destructors could still expect having access to them. Fixes #4076
110 lines
4.2 KiB
C++
110 lines
4.2 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <Kernel/FileSystem/Custody.h>
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#include <Kernel/FileSystem/FileDescription.h>
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#include <Kernel/Process.h>
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#include <Kernel/SharedBuffer.h>
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#include <Kernel/VM/Region.h>
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//#define FORK_DEBUG
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namespace Kernel {
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pid_t Process::sys$fork(RegisterState& regs)
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{
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REQUIRE_PROMISE(proc);
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RefPtr<Thread> child_first_thread;
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auto child = adopt(*new Process(child_first_thread, m_name, m_uid, m_gid, m_pid, m_is_kernel_process, m_cwd, m_executable, m_tty, this));
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if (!child_first_thread)
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return -ENOMEM;
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child->m_root_directory = m_root_directory;
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child->m_root_directory_relative_to_global_root = m_root_directory_relative_to_global_root;
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child->m_promises = m_promises;
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child->m_execpromises = m_execpromises;
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child->m_veil_state = m_veil_state;
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child->m_unveiled_paths = m_unveiled_paths;
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child->m_fds = m_fds;
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child->m_sid = m_sid;
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child->m_pg = m_pg;
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child->m_umask = m_umask;
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#ifdef FORK_DEBUG
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dbg() << "fork: child=" << child;
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#endif
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child->m_extra_gids = m_extra_gids;
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auto& child_tss = child_first_thread->m_tss;
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child_tss.eax = 0; // fork() returns 0 in the child :^)
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child_tss.ebx = regs.ebx;
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child_tss.ecx = regs.ecx;
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child_tss.edx = regs.edx;
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child_tss.ebp = regs.ebp;
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child_tss.esp = regs.userspace_esp;
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child_tss.esi = regs.esi;
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child_tss.edi = regs.edi;
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child_tss.eflags = regs.eflags;
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child_tss.eip = regs.eip;
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child_tss.cs = regs.cs;
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child_tss.ds = regs.ds;
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child_tss.es = regs.es;
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child_tss.fs = regs.fs;
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child_tss.gs = regs.gs;
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child_tss.ss = regs.userspace_ss;
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#ifdef FORK_DEBUG
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dbg() << "fork: child will begin executing at " << String::format("%w", child_tss.cs) << ":" << String::format("%x", child_tss.eip) << " with stack " << String::format("%w", child_tss.ss) << ":" << String::format("%x", child_tss.esp) << ", kstack " << String::format("%w", child_tss.ss0) << ":" << String::format("%x", child_tss.esp0);
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#endif
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SharedBuffer::share_all_shared_buffers(*this, *child);
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{
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ScopedSpinLock lock(m_lock);
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for (auto& region : m_regions) {
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#ifdef FORK_DEBUG
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dbg() << "fork: cloning Region{" << ®ion << "} '" << region.name() << "' @ " << region.vaddr();
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#endif
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auto& child_region = child->add_region(region.clone());
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child_region.map(child->page_directory());
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if (®ion == m_master_tls_region.unsafe_ptr())
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child->m_master_tls_region = child_region;
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}
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ScopedSpinLock processes_lock(g_processes_lock);
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g_processes->prepend(child);
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child->ref(); // This reference will be dropped by Process::reap
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}
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ScopedSpinLock lock(g_scheduler_lock);
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child_first_thread->set_affinity(Thread::current()->affinity());
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child_first_thread->set_state(Thread::State::Runnable);
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return child->pid().value();
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}
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}
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