From e1bcee5ff5f8e472f87ab61691bc89bf084f9854 Mon Sep 17 00:00:00 2001
From: Baye Dieng <bayedieng98@gmail.com>
Date: Sat, 12 Feb 2022 01:01:20 +0000
Subject: [PATCH] Implement kill system call

---
 Documentation/compatibility.md       |  2 +-
 kernel/syscalls/kill.rs              | 25 +++++++++++++++++++++++++
 kernel/syscalls/mod.rs               |  3 +++
 libs/kerla_utils/bitmap_allocator.rs |  2 +-
 4 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 kernel/syscalls/kill.rs

diff --git a/Documentation/compatibility.md b/Documentation/compatibility.md
index 219b3171..721edf73 100644
--- a/Documentation/compatibility.md
+++ b/Documentation/compatibility.md
@@ -82,7 +82,7 @@ Not supported.
 | 59  | execve                 | Partially             | `v0.0.1`     |                                            |
 | 60  | exit                   | Partially             | `v0.0.1`     |                                            |
 | 61  | wait4                  | Partially             | `v0.0.1`     |                                            |
-| 62  | kill                   | Unimplemented         |              |                                            |
+| 62  | kill                   | Partially             | next release              |                                            |
 | 63  | uname                  | Partially             | `v0.0.1`     |                                            |
 | 64  | semget                 | Unimplemented         |              |                                            |
 | 65  | semop                  | Unimplemented         |              |                                            |
diff --git a/kernel/syscalls/kill.rs b/kernel/syscalls/kill.rs
new file mode 100644
index 00000000..dc62a9b5
--- /dev/null
+++ b/kernel/syscalls/kill.rs
@@ -0,0 +1,25 @@
+use crate::process::{current_process, signal::Signal, PId, Process};
+use crate::result::Errno;
+use crate::result::Result;
+use crate::syscalls::SyscallHandler;
+
+impl<'a> SyscallHandler<'a> {
+    pub fn sys_kill(&self, pid: PId, sig: Signal) -> Result<isize> {
+        let pid_int = pid.as_i32();
+        match pid_int {
+            pid_int if pid_int > 0 => match Process::find_by_pid(pid) {
+                Some(proc) => proc.send_signal(sig),
+                None => return Err(Errno::ESRCH.into()),
+            },
+            0 => current_process().process_group().lock().signal(sig),
+            -1 => {
+                // TODO: check for permissions once linux capabilities is implemented
+                current_process().send_signal(sig);
+            }
+            pid_int if pid_int < -1 => current_process().process_group().lock().signal(sig),
+            _ => (),
+        }
+
+        Ok(0)
+    }
+}
diff --git a/kernel/syscalls/mod.rs b/kernel/syscalls/mod.rs
index a5b78629..9cf019bb 100644
--- a/kernel/syscalls/mod.rs
+++ b/kernel/syscalls/mod.rs
@@ -44,6 +44,7 @@ pub(self) mod getsockname;
 pub(self) mod getsockopt;
 pub(self) mod gettid;
 pub(self) mod ioctl;
+pub(self) mod kill;
 pub(self) mod link;
 pub(self) mod linkat;
 pub(self) mod listen;
@@ -138,6 +139,7 @@ const SYS_FORK: usize = 57;
 const SYS_EXECVE: usize = 59;
 const SYS_EXIT: usize = 60;
 const SYS_WAIT4: usize = 61;
+const SYS_KILL: usize = 62;
 const SYS_UNAME: usize = 63;
 const SYS_FCNTL: usize = 72;
 const SYS_FSYNC: usize = 74;
@@ -319,6 +321,7 @@ impl<'a> SyscallHandler<'a> {
                 bitflags_from_user!(WaitOptions, a3 as c_int)?,
                 UserVAddr::new(a4),
             ),
+            SYS_KILL => self.sys_kill(PId::new(a1 as i32), a2 as c_int),
             SYS_EXIT => self.sys_exit(a1 as i32),
             SYS_EXIT_GROUP => self.sys_exit_group(a1 as i32),
             SYS_SOCKET => self.sys_socket(a1 as i32, a2 as i32, a3 as i32),
diff --git a/libs/kerla_utils/bitmap_allocator.rs b/libs/kerla_utils/bitmap_allocator.rs
index a026582f..08ec2cd8 100644
--- a/libs/kerla_utils/bitmap_allocator.rs
+++ b/libs/kerla_utils/bitmap_allocator.rs
@@ -1,4 +1,4 @@
-use bitvec::{prelude::*, index::BitMask};
+use bitvec::{index::BitMask, prelude::*};
 
 use crate::alignment::align_up;