beenull/ladybird
1
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2024-11-22 23:50:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 6
ladybird/Kernel/Syscalls/disown.cpp

27 lines
612 B
C++
Raw Normal View History

Kernel+LibC: Add sys$disown() for disowning child processes This syscall allows a parent process to disown a child process, setting its parent PID to 0. Unparented processes are automatically reaped by the kernel upon exit, and no sys$waitid() is required. This will make it much nicer to do spawn-and-forget which is common in the GUI environment.
2020-08-04 11:51:11 +00:00
/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 08:24:48 +00:00
* SPDX-License-Identifier: BSD-2-Clause
Kernel+LibC: Add sys$disown() for disowning child processes This syscall allows a parent process to disown a child process, setting its parent PID to 0. Unparented processes are automatically reaped by the kernel upon exit, and no sys$waitid() is required. This will make it much nicer to do spawn-and-forget which is common in the GUI environment.
2020-08-04 11:51:11 +00:00
*/
#include <Kernel/Process.h>
namespace Kernel {
Kernel: Replace KResult and KResultOr<T> with Error and ErrorOr<T> We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace! This was a slightly tedious refactoring that took a long time, so it's not unlikely that some bugs crept in. Nevertheless, it does pass basic functionality testing, and it's just real nice to finally see the same pattern in all contexts. :^)
2021-11-07 23:51:39 +00:00
ErrorOr<FlatPtr> Process::sys$disown(ProcessID pid)
Kernel+LibC: Add sys$disown() for disowning child processes This syscall allows a parent process to disown a child process, setting its parent PID to 0. Unparented processes are automatically reaped by the kernel upon exit, and no sys$waitid() is required. This will make it much nicer to do spawn-and-forget which is common in the GUI environment.
2020-08-04 11:51:11 +00:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 18:20:12 +00:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
Kernel: Handle promise violations in the syscall handler Previously we would crash the process immediately when a promise violation was found during a syscall. This is error prone, as we don't unwind the stack. This means that in certain cases we can leak resources, like an OwnPtr / RefPtr tracked on the stack. Or even leak a lock acquired in a ScopeLockLocker. To remedy this situation we move the promise violation handling to the syscall handler, right before we return to user space. This allows the code to follow the normal unwind path, and grantees there is no longer any cleanup that needs to occur. The Process::require_promise() and Process::require_no_promises() functions were modified to return ErrorOr<void> so we enforce that the errors are always propagated by the caller.
2021-12-29 09:11:45 +00:00
TRY(require_promise(Pledge::proc));
Kernel+LibC: Add sys$disown() for disowning child processes This syscall allows a parent process to disown a child process, setting its parent PID to 0. Unparented processes are automatically reaped by the kernel upon exit, and no sys$waitid() is required. This will make it much nicer to do spawn-and-forget which is common in the GUI environment.
2020-08-04 11:51:11 +00:00
auto process = Process::from_pid(pid);
if (!process)
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 12:49:16 +00:00
return ESRCH;
Kernel+LibC: Add sys$disown() for disowning child processes This syscall allows a parent process to disown a child process, setting its parent PID to 0. Unparented processes are automatically reaped by the kernel upon exit, and no sys$waitid() is required. This will make it much nicer to do spawn-and-forget which is common in the GUI environment.
2020-08-04 11:51:11 +00:00
if (process->ppid() != this->pid())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 12:49:16 +00:00
return ECHILD;
Kernel: Guard Process "protected data" with a spinlock This ensures that both mutable and immutable access to the protected data of a process is serialized. Note that there may still be multiple TOCTOU issues around this, as we have a bunch of convenience accessors that make it easy to introduce them. We'll need to audit those as well.
2022-08-21 10:18:26 +00:00
process->with_mutable_protected_data([](auto& protected_data) {
protected_data.ppid = 0;
});
Kernel: disown should unblock any potential waiters This is necessary because if a process changes the state to Stopped or resumes from that state, a wait entry is created in the parent process. So, if a child process does this before disown is called, we need to clear those entries to avoid leaking references/zombies that won't be cleaned up until the former parent exits. This also should solve an even more unlikely corner case where another thread is waiting on a pid that is being disowned by another thread.
2020-12-09 02:04:05 +00:00
process->disowned_by_waiter(*this);
Kernel+LibC: Add sys$disown() for disowning child processes This syscall allows a parent process to disown a child process, setting its parent PID to 0. Unparented processes are automatically reaped by the kernel upon exit, and no sys$waitid() is required. This will make it much nicer to do spawn-and-forget which is common in the GUI environment.
2020-08-04 11:51:11 +00:00
return 0;
}
}
Reference in a new issue Copy permalink