redox/kernel/syscall/process.rs
2016-11-17 14:23:41 -07:00

932 lines
34 KiB
Rust

///! Process syscalls
use alloc::arc::Arc;
use alloc::boxed::Box;
use collections::{BTreeMap, Vec};
use core::{intrinsics, mem, str};
use core::ops::DerefMut;
use spin::Mutex;
use arch;
use arch::memory::allocate_frame;
use arch::paging::{ActivePageTable, InactivePageTable, Page, VirtualAddress, entry};
use arch::paging::temporary_page::TemporaryPage;
use arch::start::usermode;
use context;
use context::ContextId;
use elf::{self, program_header};
use scheme::{self, FileHandle};
use syscall;
use syscall::data::Stat;
use syscall::error::*;
use syscall::flag::{CLONE_VFORK, CLONE_VM, CLONE_FS, CLONE_FILES, WNOHANG};
use syscall::validate::{validate_slice, validate_slice_mut};
pub fn brk(address: usize) -> Result<usize> {
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
let context = context_lock.read();
let current = if let Some(ref heap_shared) = context.heap {
heap_shared.with(|heap| {
heap.start_address().get() + heap.size()
})
} else {
panic!("user heap not initialized");
};
if address == 0 {
//println!("Brk query {:X}", current);
Ok(current)
} else if address >= arch::USER_HEAP_OFFSET {
//TODO: out of memory errors
if let Some(ref heap_shared) = context.heap {
heap_shared.with(|heap| {
heap.resize(address - arch::USER_HEAP_OFFSET, true, true);
});
} else {
panic!("user heap not initialized");
}
Ok(address)
} else {
Err(Error::new(ENOMEM))
}
}
pub fn clone(flags: usize, stack_base: usize) -> Result<ContextId> {
let ppid;
let pid;
{
let ruid;
let rgid;
let euid;
let egid;
let mut cpu_id = None;
let arch;
let vfork;
let mut kfx_option = None;
let mut kstack_option = None;
let mut offset = 0;
let mut image = vec![];
let mut heap_option = None;
let mut stack_option = None;
let mut tls_option = None;
let grants;
let name;
let scheme_ns;
let cwd;
let env;
let files;
// Copy from old process
{
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
let context = context_lock.read();
ppid = context.id;
ruid = context.ruid;
rgid = context.rgid;
euid = context.euid;
egid = context.egid;
if flags & CLONE_VM == CLONE_VM {
cpu_id = context.cpu_id;
}
arch = context.arch.clone();
if let Some(ref fx) = context.kfx {
let mut new_fx = unsafe { Box::from_raw(::alloc::heap::allocate(512, 16) as *mut [u8; 512]) };
for (new_b, b) in new_fx.iter_mut().zip(fx.iter()) {
*new_b = *b;
}
kfx_option = Some(new_fx);
}
if let Some(ref stack) = context.kstack {
offset = stack_base - stack.as_ptr() as usize - mem::size_of::<usize>(); // Add clone ret
let mut new_stack = stack.clone();
unsafe {
let func_ptr = new_stack.as_mut_ptr().offset(offset as isize);
*(func_ptr as *mut usize) = arch::interrupt::syscall::clone_ret as usize;
}
kstack_option = Some(new_stack);
}
if flags & CLONE_VM == CLONE_VM {
for memory_shared in context.image.iter() {
image.push(memory_shared.clone());
}
if let Some(ref heap_shared) = context.heap {
heap_option = Some(heap_shared.clone());
}
} else {
for memory_shared in context.image.iter() {
memory_shared.with(|memory| {
let mut new_memory = context::memory::Memory::new(
VirtualAddress::new(memory.start_address().get() + arch::USER_TMP_OFFSET),
memory.size(),
entry::PRESENT | entry::NO_EXECUTE | entry::WRITABLE,
true,
false
);
unsafe {
intrinsics::copy(memory.start_address().get() as *const u8,
new_memory.start_address().get() as *mut u8,
memory.size());
}
new_memory.remap(memory.flags(), true);
image.push(new_memory.to_shared());
});
}
if let Some(ref heap_shared) = context.heap {
heap_shared.with(|heap| {
let mut new_heap = context::memory::Memory::new(
VirtualAddress::new(arch::USER_TMP_HEAP_OFFSET),
heap.size(),
entry::PRESENT | entry::NO_EXECUTE | entry::WRITABLE,
true,
false
);
unsafe {
intrinsics::copy(heap.start_address().get() as *const u8,
new_heap.start_address().get() as *mut u8,
heap.size());
}
new_heap.remap(heap.flags(), true);
heap_option = Some(new_heap.to_shared());
});
}
}
if let Some(ref stack) = context.stack {
let mut new_stack = context::memory::Memory::new(
VirtualAddress::new(arch::USER_TMP_STACK_OFFSET),
stack.size(),
entry::PRESENT | entry::NO_EXECUTE | entry::WRITABLE,
true,
false
);
unsafe {
intrinsics::copy(stack.start_address().get() as *const u8,
new_stack.start_address().get() as *mut u8,
stack.size());
}
new_stack.remap(stack.flags(), true);
stack_option = Some(new_stack);
}
if let Some(ref tls) = context.tls {
let mut new_tls = context::memory::Tls {
master: tls.master,
file_size: tls.file_size,
mem: context::memory::Memory::new(
VirtualAddress::new(arch::USER_TMP_TLS_OFFSET),
tls.mem.size(),
entry::PRESENT | entry::NO_EXECUTE | entry::WRITABLE,
true,
true
)
};
unsafe {
intrinsics::copy(tls.master.get() as *const u8,
new_tls.mem.start_address().get() as *mut u8,
tls.file_size);
}
new_tls.mem.remap(tls.mem.flags(), true);
tls_option = Some(new_tls);
}
if flags & CLONE_VM == CLONE_VM {
grants = context.grants.clone();
} else {
grants = Arc::new(Mutex::new(Vec::new()));
}
if flags & CLONE_VM == CLONE_VM {
name = context.name.clone();
} else {
name = Arc::new(Mutex::new(context.name.lock().clone()));
}
scheme_ns = context.scheme_ns;
if flags & CLONE_FS == CLONE_FS {
cwd = context.cwd.clone();
} else {
cwd = Arc::new(Mutex::new(context.cwd.lock().clone()));
}
if flags & CLONE_VM == CLONE_VM {
env = context.env.clone();
} else {
let mut new_env = BTreeMap::new();
for item in context.env.lock().iter() {
new_env.insert(item.0.clone(), Arc::new(Mutex::new(item.1.lock().clone())));
}
env = Arc::new(Mutex::new(new_env));
}
if flags & CLONE_FILES == CLONE_FILES {
files = context.files.clone();
} else {
files = Arc::new(Mutex::new(context.files.lock().clone()));
}
}
// If not cloning files, dup to get a new number from scheme
// This has to be done outside the context lock to prevent deadlocks
if flags & CLONE_FILES == 0 {
for (_fd, mut file_option) in files.lock().iter_mut().enumerate() {
let new_file_option = if let Some(file) = *file_option {
let result = {
let scheme = {
let schemes = scheme::schemes();
let scheme = schemes.get(file.scheme).ok_or(Error::new(EBADF))?;
scheme.clone()
};
let result = scheme.dup(file.number, b"clone");
result
};
match result {
Ok(new_number) => {
Some(context::file::File {
scheme: file.scheme,
number: new_number,
event: None,
})
},
Err(_err) => {
None
}
}
} else {
None
};
*file_option = new_file_option;
}
}
// If vfork, block the current process
// This has to be done after the operations that may require context switches
if flags & CLONE_VFORK == CLONE_VFORK {
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
let mut context = context_lock.write();
context.block();
vfork = true;
} else {
vfork = false;
}
// Set up new process
{
let mut contexts = context::contexts_mut();
let context_lock = contexts.new_context()?;
let mut context = context_lock.write();
pid = context.id;
context.ppid = ppid;
context.ruid = ruid;
context.rgid = rgid;
context.euid = euid;
context.egid = egid;
context.cpu_id = cpu_id;
context.status = context::Status::Runnable;
context.vfork = vfork;
context.arch = arch;
let mut active_table = unsafe { ActivePageTable::new() };
let mut temporary_page = TemporaryPage::new(Page::containing_address(VirtualAddress::new(0x8_0000_0000)));
let mut new_table = {
let frame = allocate_frame().expect("no more frames in syscall::clone new_table");
InactivePageTable::new(frame, &mut active_table, &mut temporary_page)
};
context.arch.set_page_table(unsafe { new_table.address() });
// Copy kernel mapping
{
let frame = active_table.p4()[510].pointed_frame().expect("kernel table not mapped");
let flags = active_table.p4()[510].flags();
active_table.with(&mut new_table, &mut temporary_page, |mapper| {
mapper.p4_mut()[510].set(frame, flags);
});
}
if let Some(fx) = kfx_option.take() {
context.arch.set_fx(fx.as_ptr() as usize);
context.kfx = Some(fx);
}
// Set kernel stack
if let Some(stack) = kstack_option.take() {
context.arch.set_stack(stack.as_ptr() as usize + offset);
context.kstack = Some(stack);
}
// Setup heap
if flags & CLONE_VM == CLONE_VM {
// Copy user image mapping, if found
if ! image.is_empty() {
let frame = active_table.p4()[0].pointed_frame().expect("user image not mapped");
let flags = active_table.p4()[0].flags();
active_table.with(&mut new_table, &mut temporary_page, |mapper| {
mapper.p4_mut()[0].set(frame, flags);
});
}
context.image = image;
// Copy user heap mapping, if found
if let Some(heap_shared) = heap_option {
let frame = active_table.p4()[1].pointed_frame().expect("user heap not mapped");
let flags = active_table.p4()[1].flags();
active_table.with(&mut new_table, &mut temporary_page, |mapper| {
mapper.p4_mut()[1].set(frame, flags);
});
context.heap = Some(heap_shared);
}
// Copy grant mapping
if ! grants.lock().is_empty() {
let frame = active_table.p4()[2].pointed_frame().expect("user grants not mapped");
let flags = active_table.p4()[2].flags();
active_table.with(&mut new_table, &mut temporary_page, |mapper| {
mapper.p4_mut()[2].set(frame, flags);
});
}
context.grants = grants;
} else {
// Copy percpu mapping
for cpu_id in 0..::cpu_count() {
extern {
/// The starting byte of the thread data segment
static mut __tdata_start: u8;
/// The ending byte of the thread BSS segment
static mut __tbss_end: u8;
}
let size = unsafe { & __tbss_end as *const _ as usize - & __tdata_start as *const _ as usize };
let start = arch::KERNEL_PERCPU_OFFSET + arch::KERNEL_PERCPU_SIZE * cpu_id;
let end = start + size;
let start_page = Page::containing_address(VirtualAddress::new(start));
let end_page = Page::containing_address(VirtualAddress::new(end - 1));
for page in Page::range_inclusive(start_page, end_page) {
let frame = active_table.translate_page(page).expect("kernel percpu not mapped");
active_table.with(&mut new_table, &mut temporary_page, |mapper| {
mapper.map_to(page, frame, entry::PRESENT | entry::NO_EXECUTE | entry::WRITABLE);
});
}
}
// Move copy of image
for memory_shared in image.iter_mut() {
memory_shared.with(|memory| {
let start = VirtualAddress::new(memory.start_address().get() - arch::USER_TMP_OFFSET + arch::USER_OFFSET);
memory.move_to(start, &mut new_table, &mut temporary_page, true);
});
}
context.image = image;
// Move copy of heap
if let Some(heap_shared) = heap_option {
heap_shared.with(|heap| {
heap.move_to(VirtualAddress::new(arch::USER_HEAP_OFFSET), &mut new_table, &mut temporary_page, true);
});
context.heap = Some(heap_shared);
}
}
// Setup user stack
if let Some(mut stack) = stack_option {
stack.move_to(VirtualAddress::new(arch::USER_STACK_OFFSET), &mut new_table, &mut temporary_page, true);
context.stack = Some(stack);
}
// Setup user TLS
if let Some(mut tls) = tls_option {
tls.mem.move_to(VirtualAddress::new(arch::USER_TLS_OFFSET), &mut new_table, &mut temporary_page, true);
context.tls = Some(tls);
}
context.name = name;
context.scheme_ns = scheme_ns;
context.cwd = cwd;
context.env = env;
context.files = files;
}
}
unsafe { context::switch(); }
Ok(pid)
}
pub fn exec(path: &[u8], arg_ptrs: &[[usize; 2]]) -> Result<usize> {
let entry;
let mut sp = arch::USER_STACK_OFFSET + arch::USER_STACK_SIZE - 256;
{
let mut args = Vec::new();
for arg_ptr in arg_ptrs {
let arg = validate_slice(arg_ptr[0] as *const u8, arg_ptr[1])?;
args.push(arg.to_vec()); // Must be moved into kernel space before exec unmaps all memory
}
let (uid, gid, canonical) = {
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
let context = context_lock.read();
(context.euid, context.egid, context.canonicalize(path))
};
let file = syscall::open(&canonical, 0)?;
let mut stat = Stat::default();
syscall::file_op_mut_slice(syscall::number::SYS_FSTAT, file, &mut stat)?;
let mut perm = stat.st_mode & 0o7;
if stat.st_uid == uid {
perm |= (stat.st_mode >> 6) & 0o7;
}
if stat.st_gid == gid {
perm |= (stat.st_mode >> 3) & 0o7;
}
if uid == 0 {
perm |= 0o7;
}
if perm & 0o1 != 0o1 {
let _ = syscall::close(file);
return Err(Error::new(EACCES));
}
//TODO: Only read elf header, not entire file. Then read required segments
let mut data = vec![0; stat.st_size as usize];
syscall::file_op_mut_slice(syscall::number::SYS_READ, file, &mut data)?;
let _ = syscall::close(file);
match elf::Elf::from(&data) {
Ok(elf) => {
entry = elf.entry();
drop(path); // Drop so that usage is not allowed after unmapping context
drop(arg_ptrs); // Drop so that usage is not allowed after unmapping context
let contexts = context::contexts();
let (vfork, ppid, files) = {
let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
let mut context = context_lock.write();
// Set name
context.name = Arc::new(Mutex::new(canonical));
// Unmap previous image, heap, grants, stack, and tls
context.image.clear();
drop(context.heap.take());
context.grants = Arc::new(Mutex::new(Vec::new()));
drop(context.stack.take());
drop(context.tls.take());
if stat.st_mode & syscall::flag::MODE_SETUID == syscall::flag::MODE_SETUID {
context.euid = stat.st_uid;
}
if stat.st_mode & syscall::flag::MODE_SETGID == syscall::flag::MODE_SETGID {
context.egid = stat.st_gid;
}
// Map and copy new segments
let mut tls_option = None;
for segment in elf.segments() {
if segment.p_type == program_header::PT_LOAD {
let mut memory = context::memory::Memory::new(
VirtualAddress::new(segment.p_vaddr as usize),
segment.p_memsz as usize,
entry::NO_EXECUTE | entry::WRITABLE,
true,
true
);
unsafe {
// Copy file data
intrinsics::copy((elf.data.as_ptr() as usize + segment.p_offset as usize) as *const u8,
segment.p_vaddr as *mut u8,
segment.p_filesz as usize);
}
let mut flags = entry::NO_EXECUTE | entry::USER_ACCESSIBLE;
if segment.p_flags & program_header::PF_R == program_header::PF_R {
flags.insert(entry::PRESENT);
}
// W ^ X. If it is executable, do not allow it to be writable, even if requested
if segment.p_flags & program_header::PF_X == program_header::PF_X {
flags.remove(entry::NO_EXECUTE);
} else if segment.p_flags & program_header::PF_W == program_header::PF_W {
flags.insert(entry::WRITABLE);
}
memory.remap(flags, true);
context.image.push(memory.to_shared());
} else if segment.p_type == program_header::PT_TLS {
let memory = context::memory::Memory::new(
VirtualAddress::new(arch::USER_TCB_OFFSET),
4096,
entry::NO_EXECUTE | entry::WRITABLE | entry::USER_ACCESSIBLE,
true,
true
);
unsafe { *(arch::USER_TCB_OFFSET as *mut usize) = arch::USER_TLS_OFFSET + segment.p_memsz as usize; }
context.image.push(memory.to_shared());
tls_option = Some((
VirtualAddress::new(segment.p_vaddr as usize),
segment.p_filesz as usize,
segment.p_memsz as usize
));
}
}
// Map heap
context.heap = Some(context::memory::Memory::new(
VirtualAddress::new(arch::USER_HEAP_OFFSET),
0,
entry::NO_EXECUTE | entry::WRITABLE | entry::USER_ACCESSIBLE,
true,
true
).to_shared());
// Map stack
context.stack = Some(context::memory::Memory::new(
VirtualAddress::new(arch::USER_STACK_OFFSET),
arch::USER_STACK_SIZE,
entry::NO_EXECUTE | entry::WRITABLE | entry::USER_ACCESSIBLE,
true,
true
));
// Map TLS
if let Some((master, file_size, size)) = tls_option {
let tls = context::memory::Tls {
master: master,
file_size: file_size,
mem: context::memory::Memory::new(
VirtualAddress::new(arch::USER_TLS_OFFSET),
size,
entry::NO_EXECUTE | entry::WRITABLE | entry::USER_ACCESSIBLE,
true,
true
)
};
unsafe {
// Copy file data
intrinsics::copy(master.get() as *const u8,
tls.mem.start_address().get() as *mut u8,
file_size);
}
context.tls = Some(tls);
}
// Push arguments
let mut arg_size = 0;
for arg in args.iter().rev() {
sp -= mem::size_of::<usize>();
unsafe { *(sp as *mut usize) = arch::USER_ARG_OFFSET + arg_size; }
sp -= mem::size_of::<usize>();
unsafe { *(sp as *mut usize) = arg.len(); }
arg_size += arg.len();
}
sp -= mem::size_of::<usize>();
unsafe { *(sp as *mut usize) = args.len(); }
if arg_size > 0 {
let mut memory = context::memory::Memory::new(
VirtualAddress::new(arch::USER_ARG_OFFSET),
arg_size,
entry::NO_EXECUTE | entry::WRITABLE,
true,
true
);
let mut arg_offset = 0;
for arg in args.iter().rev() {
unsafe {
intrinsics::copy(arg.as_ptr(),
(arch::USER_ARG_OFFSET + arg_offset) as *mut u8,
arg.len());
}
arg_offset += arg.len();
}
memory.remap(entry::NO_EXECUTE | entry::USER_ACCESSIBLE, true);
context.image.push(memory.to_shared());
}
let files = Arc::new(Mutex::new(context.files.lock().clone()));
context.files = files.clone();
let vfork = context.vfork;
context.vfork = false;
(vfork, context.ppid, files)
};
// Duplicate current files using b"exec", close previous
for (fd, mut file_option) in files.lock().iter_mut().enumerate() {
let new_file_option = if let Some(file) = *file_option {
// Duplicate
let result = {
let scheme_option = {
let schemes = scheme::schemes();
schemes.get(file.scheme).map(|scheme| scheme.clone())
};
if let Some(scheme) = scheme_option {
let result = scheme.dup(file.number, b"exec");
result
} else {
Err(Error::new(EBADF))
}
};
// Close
{
if let Some(event_id) = file.event {
context::event::unregister(FileHandle::from(fd), file.scheme, event_id);
}
let scheme_option = {
let schemes = scheme::schemes();
schemes.get(file.scheme).map(|scheme| scheme.clone())
};
if let Some(scheme) = scheme_option {
let _ = scheme.close(file.number);
}
}
// Return new descriptor
match result {
Ok(new_number) => {
Some(context::file::File {
scheme: file.scheme,
number: new_number,
event: None,
})
},
Err(_err) => {
None
}
}
} else {
None
};
*file_option = new_file_option;
}
if vfork {
if let Some(context_lock) = contexts.get(ppid) {
let mut context = context_lock.write();
if ! context.unblock() {
println!("{:?} not blocked for exec vfork unblock", ppid);
}
} else {
println!("{:?} not found for exec vfork unblock", ppid);
}
}
},
Err(err) => {
println!("failed to execute {}: {}", unsafe { str::from_utf8_unchecked(path) }, err);
return Err(Error::new(ENOEXEC));
}
}
}
// Go to usermode
unsafe { usermode(entry, sp); }
}
pub fn exit(status: usize) -> ! {
{
let context_lock = {
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH)).expect("exit failed to find context");
context_lock.clone()
};
let mut close_files = Vec::new();
let (pid, ppid) = {
let mut context = context_lock.write();
if Arc::strong_count(&context.files) == 1 { // FIXME: Looks like a race condition.
mem::swap(context.files.lock().deref_mut(), &mut close_files);
}
context.files = Arc::new(Mutex::new(Vec::new()));
(context.id, context.ppid)
};
/// Files must be closed while context is valid so that messages can be passed
for (fd, file_option) in close_files.drain(..).enumerate() {
if let Some(file) = file_option {
if let Some(event_id) = file.event {
context::event::unregister(FileHandle::from(fd), file.scheme, event_id);
}
let scheme_option = {
let schemes = scheme::schemes();
schemes.get(file.scheme).map(|scheme| scheme.clone())
};
if let Some(scheme) = scheme_option {
let _ = scheme.close(file.number);
}
}
}
/// Transfer child processes to parent
{
let contexts = context::contexts();
for (_id, context_lock) in contexts.iter() {
let mut context = context_lock.write();
if context.ppid == pid {
context.ppid = ppid;
context.vfork = false;
}
}
}
let (vfork, children) = {
let mut context = context_lock.write();
context.image.clear();
drop(context.heap.take());
drop(context.stack.take());
drop(context.tls.take());
context.grants = Arc::new(Mutex::new(Vec::new()));
let vfork = context.vfork;
context.vfork = false;
context.status = context::Status::Exited(status);
let children = context.waitpid.receive_all();
(vfork, children)
};
{
let contexts = context::contexts();
if let Some(parent_lock) = contexts.get(ppid) {
let waitpid = {
let mut parent = parent_lock.write();
if vfork {
if ! parent.unblock() {
println!("{:?} not blocked for exit vfork unblock", ppid);
}
}
parent.waitpid.clone()
};
for (c_pid, c_status) in children {
waitpid.send(c_pid, c_status);
}
waitpid.send(pid, status);
} else {
println!("{:?} not found for exit vfork unblock", ppid);
}
}
}
unsafe { context::switch(); }
unreachable!();
}
pub fn getpid() -> Result<ContextId> {
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
let context = context_lock.read();
Ok(context.id)
}
pub fn kill(pid: ContextId, sig: usize) -> Result<usize> {
let (ruid, euid) = {
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
let context = context_lock.read();
(context.ruid, context.euid)
};
if sig > 0 && sig <= 0x7F {
let contexts = context::contexts();
let context_lock = contexts.get(pid).ok_or(Error::new(ESRCH))?;
let mut context = context_lock.write();
if euid == 0
|| euid == context.ruid
|| ruid == context.ruid
{
context.pending.push_back(sig as u8);
Ok(0)
} else {
Err(Error::new(EPERM))
}
} else {
Err(Error::new(EINVAL))
}
}
fn reap(pid: ContextId) -> Result<ContextId> {
// Spin until not running
let mut running = false;
while running {
{
let contexts = context::contexts();
let context_lock = contexts.get(pid).ok_or(Error::new(ESRCH))?;
let context = context_lock.read();
running = context.running;
}
arch::interrupt::pause();
}
let mut contexts = context::contexts_mut();
contexts.remove(pid).ok_or(Error::new(ESRCH)).and(Ok(pid))
}
pub fn waitpid(pid: ContextId, status_ptr: usize, flags: usize) -> Result<ContextId> {
let waitpid = {
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
let context = context_lock.read();
context.waitpid.clone()
};
let mut tmp = [0];
let status_slice = if status_ptr != 0 {
validate_slice_mut(status_ptr as *mut usize, 1)?
} else {
&mut tmp
};
if pid.into() == 0 {
if flags & WNOHANG == WNOHANG {
if let Some((w_pid, status)) = waitpid.receive_any_nonblock() {
status_slice[0] = status;
reap(w_pid)
} else {
Ok(ContextId::from(0))
}
} else {
let (w_pid, status) = waitpid.receive_any();
status_slice[0] = status;
reap(w_pid)
}
} else {
if flags & WNOHANG == WNOHANG {
if let Some(status) = waitpid.receive_nonblock(&pid) {
status_slice[0] = status;
reap(pid)
} else {
Ok(ContextId::from(0))
}
} else {
let status = waitpid.receive(&pid);
status_slice[0] = status;
reap(pid)
}
}
}