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ladybird/Kernel/Syscalls/fork.cpp

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Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Process.h>
Kernel: Inherit shared buffers when forking 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
2020-11-23 01:25:48 +03:00
#include <Kernel/SharedBuffer.h>
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
#include <Kernel/VM/Region.h>
//#define FORK_DEBUG
namespace Kernel {
pid_t Process::sys$fork(RegisterState& regs)
{
REQUIRE_PROMISE(proc);
Kernel: Make Thread refcounted Similar to Process, we need to make Thread refcounted. This will solve problems that will appear once we schedule threads on more than one processor. This allows us to hold onto threads without necessarily holding the scheduler lock for the entire duration.
2020-09-27 17:53:35 +03:00
RefPtr<Thread> child_first_thread;
auto child = adopt(*new Process(child_first_thread, m_name, m_uid, m_gid, m_pid, m_is_kernel_process, m_cwd, m_executable, m_tty, this));
if (!child_first_thread)
return -ENOMEM;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
child->m_root_directory = m_root_directory;
child->m_root_directory_relative_to_global_root = m_root_directory_relative_to_global_root;
child->m_promises = m_promises;
child->m_execpromises = m_execpromises;
child->m_veil_state = m_veil_state;
child->m_unveiled_paths = m_unveiled_paths;
child->m_fds = m_fds;
child->m_sid = m_sid;
Kernel: Distinguish between new and old process groups with equal pgids This does not add any behaviour change to the processes, but it ties a TTY to an active process group via TIOCSPGRP, and returns the TTY to the kernel when all processes in the process group die. Also makes the TTY keep a link to the original controlling process' parent (for SIGCHLD) instead of the process itself.
2020-08-15 22:13:19 +03:00
child->m_pg = m_pg;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
child->m_umask = m_umask;
#ifdef FORK_DEBUG
dbg() << "fork: child=" << child;
#endif
child->m_extra_gids = m_extra_gids;
auto& child_tss = child_first_thread->m_tss;
child_tss.eax = 0; // fork() returns 0 in the child :^)
child_tss.ebx = regs.ebx;
child_tss.ecx = regs.ecx;
child_tss.edx = regs.edx;
child_tss.ebp = regs.ebp;
child_tss.esp = regs.userspace_esp;
child_tss.esi = regs.esi;
child_tss.edi = regs.edi;
child_tss.eflags = regs.eflags;
child_tss.eip = regs.eip;
child_tss.cs = regs.cs;
child_tss.ds = regs.ds;
child_tss.es = regs.es;
child_tss.fs = regs.fs;
child_tss.gs = regs.gs;
child_tss.ss = regs.userspace_ss;
#ifdef FORK_DEBUG
AK: Remove custom %w format string specifier This was a non-standard specifier alias for %04x. This patch replaces all uses of it with new-style formatting functions instead.
2020-12-25 19:05:05 +03:00
dbgln("fork: child will begin executing at {:04x}:{:08x} with stack {:04x}:{:08x}, kstack {:04x}:{:08x}", child_tss.cs, child_tss.eip, child_tss.ss, child_tss.esp, child_tss.ss0, child_tss.esp0);
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
#endif
Kernel: Inherit shared buffers when forking 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
2020-11-23 01:25:48 +03:00
SharedBuffer::share_all_shared_buffers(*this, *child);
Kernel: Fix a few deadlocks with Thread::m_lock and g_scheduler_lock g_scheduler_lock cannot safely be acquired after Thread::m_lock because another processor may already hold g_scheduler_lock and wait for the same Thread::m_lock.
2020-10-26 05:22:59 +03:00
{
ScopedSpinLock lock(m_lock);
for (auto& region : m_regions) {
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
#ifdef FORK_DEBUG
Kernel: Fix a few deadlocks with Thread::m_lock and g_scheduler_lock g_scheduler_lock cannot safely be acquired after Thread::m_lock because another processor may already hold g_scheduler_lock and wait for the same Thread::m_lock.
2020-10-26 05:22:59 +03:00
dbg() << "fork: cloning Region{" << &region << "} '" << region.name() << "' @ " << region.vaddr();
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
#endif
Kernel: Fix a few deadlocks with Thread::m_lock and g_scheduler_lock g_scheduler_lock cannot safely be acquired after Thread::m_lock because another processor may already hold g_scheduler_lock and wait for the same Thread::m_lock.
2020-10-26 05:22:59 +03:00
auto& child_region = child->add_region(region.clone());
child_region.map(child->page_directory());
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
AK: Make RefPtr, NonnullRefPtr, WeakPtr thread safe This makes most operations thread safe, especially so that they can safely be used in the Kernel. This includes obtaining a strong reference from a weak reference, which now requires an explicit call to WeakPtr::strong_ref(). Another major change is that Weakable::make_weak_ref() may require the explicit target type. Previously we used reinterpret_cast in WeakPtr, assuming that it can be properly converted. But WeakPtr does not necessarily have the knowledge to be able to do this. Instead, we now ask the class itself to deliver a WeakPtr to the type that we want. Also, WeakLink is no longer specific to a target type. The reason for this is that we want to be able to safely convert e.g. WeakPtr<T> to WeakPtr<U>, and before this we just reinterpret_cast the internal WeakLink<T> to WeakLink<U>, which is a bold assumption that it would actually produce the correct code. Instead, WeakLink now operates on just a raw pointer and we only make those constructors/operators available if we can verify that it can be safely cast. In order to guarantee thread safety, we now use the least significant bit in the pointer for locking purposes. This also means that only properly aligned pointers can be used.
2020-09-30 01:26:13 +03:00
if (&region == m_master_tls_region.unsafe_ptr())
child->m_master_tls_region = child_region;
Kernel: Fix a few deadlocks with Thread::m_lock and g_scheduler_lock g_scheduler_lock cannot safely be acquired after Thread::m_lock because another processor may already hold g_scheduler_lock and wait for the same Thread::m_lock.
2020-10-26 05:22:59 +03:00
}
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
Kernel: Fix a few deadlocks with Thread::m_lock and g_scheduler_lock g_scheduler_lock cannot safely be acquired after Thread::m_lock because another processor may already hold g_scheduler_lock and wait for the same Thread::m_lock.
2020-10-26 05:22:59 +03:00
ScopedSpinLock processes_lock(g_processes_lock);
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
g_processes->prepend(child);
Kernel: Make Thread refcounted Similar to Process, we need to make Thread refcounted. This will solve problems that will appear once we schedule threads on more than one processor. This allows us to hold onto threads without necessarily holding the scheduler lock for the entire duration.
2020-09-27 17:53:35 +03:00
child->ref(); // This reference will be dropped by Process::reap
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
}
Kernel: Fix a few deadlocks with Thread::m_lock and g_scheduler_lock g_scheduler_lock cannot safely be acquired after Thread::m_lock because another processor may already hold g_scheduler_lock and wait for the same Thread::m_lock.
2020-10-26 05:22:59 +03:00
ScopedSpinLock lock(g_scheduler_lock);
Kernel: Fix crash when delivering signal to barely created thread We need to wait until a thread is fully set up and ready for running before attempting to deliver a signal. Otherwise we may not have a user stack yet. Also, remove the Skip0SchedulerPasses and Skip1SchedulerPass thread states that we don't really need anymore with software context switching. Fixes the kernel crash reported in #3419
2020-09-07 17:31:00 +03:00
child_first_thread->set_affinity(Thread::current()->affinity());
child_first_thread->set_state(Thread::State::Runnable);
Kernel: PID/TID typing This compiles, and contains exactly the same bugs as before. The regex 'FIXME: PID/' should reveal all markers that I left behind, including: - Incomplete conversion - Issues or things that look fishy - Actual bugs that will go wrong during runtime
2020-08-08 18:32:34 +03:00
return child->pid().value();
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
}
}
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