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Kernel: Simplify Process constructor

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Move all the fork-specific inheritance logic to sys$fork(), and all the
stuff for setting up stdio for non-fork ring 3 processes moves to
Process::create_user_process().

Also: we were setting up the PGID, SID and umask twice. Also the code
for copying the open file descriptors was overly complicated. Now it's
just a simple Vector copy assignment. :^)
This commit is contained in:
Andreas Kling 2020-01-25 13:50:54 +01:00
parent c05c023664
commit 69de90a625
1 changed files with 13 additions and 40 deletions
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53
Kernel/Process.cpp
View file

@ -641,6 +641,10 @@ pid_t Process::sys$fork(RegisterDump& regs)
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;
child->m_pgid = m_pgid;
child->m_umask = m_umask;
#ifdef FORK_DEBUG
dbgprintf("fork: child=%p\n", child);
@ -1207,6 +1211,11 @@ Process* Process::create_user_process(Thread*& first_thread, const String& path,
root = VFS::the().root_custody();
auto* process = new Process(first_thread, parts.take_last(), uid, gid, parent_pid, Ring3, move(cwd), nullptr, tty);
process->m_fds.resize(m_max_open_file_descriptors);
auto& device_to_use_as_tty = tty ? (CharacterDevice&)*tty : NullDevice::the();
process->m_fds[0].set(*device_to_use_as_tty.open(O_RDONLY).value());
process->m_fds[1].set(*device_to_use_as_tty.open(O_WRONLY).value());
process->m_fds[2].set(*device_to_use_as_tty.open(O_WRONLY).value());
error = process->exec(path, move(arguments), move(environment));
if (error != 0) {
@ -1262,48 +1271,12 @@ Process::Process(Thread*& first_thread, const String& name, uid_t uid, gid_t gid
dbgprintf("Process %u ctor: PD=%x created\n", pid(), m_page_directory.ptr());
#endif
// NOTE: fork() doesn't clone all threads; the thread that called fork() becomes the main thread in the new process.
if (fork_parent)
if (fork_parent) {
// NOTE: fork() doesn't clone all threads; the thread that called fork() becomes the only thread in the new process.
first_thread = current->clone(*this);
else
first_thread = new Thread(*this);
//m_gids.set(m_gid);
if (fork_parent) {
m_sid = fork_parent->m_sid;
m_pgid = fork_parent->m_pgid;
} else {
// FIXME: Use a ProcessHandle? Presumably we're executing *IN* the parent right now though..
InterruptDisabler disabler;
if (auto* parent = Process::from_pid(m_ppid)) {
m_sid = parent->m_sid;
m_pgid = parent->m_pgid;
}
}
if (fork_parent) {
m_fds.resize(fork_parent->m_fds.size());
for (int i = 0; i < fork_parent->m_fds.size(); ++i) {
if (!fork_parent->m_fds[i].description)
continue;
#ifdef FORK_DEBUG
dbgprintf("fork: cloning fd %u... (%p) istty? %u\n", i, fork_parent->m_fds[i].description.ptr(), fork_parent->m_fds[i].description->is_tty());
#endif
m_fds[i] = fork_parent->m_fds[i];
}
} else if (ring == Ring3) {
m_fds.resize(m_max_open_file_descriptors);
auto& device_to_use_as_tty = tty ? (CharacterDevice&)*tty : NullDevice::the();
m_fds[0].set(*device_to_use_as_tty.open(O_RDONLY).value());
m_fds[1].set(*device_to_use_as_tty.open(O_WRONLY).value());
m_fds[2].set(*device_to_use_as_tty.open(O_WRONLY).value());
}
if (fork_parent) {
m_sid = fork_parent->m_sid;
m_pgid = fork_parent->m_pgid;
m_umask = fork_parent->m_umask;
// NOTE: This non-forked code path is only taken when the kernel creates a process "manually" (at boot.)
first_thread = new Thread(*this);
}
}