From 85cbdc05c1ec6e3e893f087f3f054c8c63bca0b5 Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Mon, 9 Sep 2024 18:03:49 -0300
Subject: [PATCH] syscalls: killthread

---
 kernel-src/arch/x86-64/syscall.asm     |  4 +-
 kernel-src/arch/x86-64/syscalllog.c    |  8 ++--
 kernel-src/sys/syscalls/killthread.c   | 58 ++++++++++++++++++++++++++
 patches/mlibc/jinx-working-patch.patch | 14 +++++--
 4 files changed, 76 insertions(+), 8 deletions(-)
 create mode 100644 kernel-src/sys/syscalls/killthread.c

diff --git a/kernel-src/arch/x86-64/syscall.asm b/kernel-src/arch/x86-64/syscall.asm
index 794c9a9e..e3e0e3f0 100644
--- a/kernel-src/arch/x86-64/syscall.asm
+++ b/kernel-src/arch/x86-64/syscall.asm
@@ -90,6 +90,7 @@ extern syscall_setegid
 extern syscall_sigsuspend
 extern syscall_sigtimedwait
 extern syscall_sigpending
+extern syscall_killthread
 syscalltab:
 dq syscall_print
 dq syscall_mmap
@@ -182,7 +183,8 @@ dq syscall_setegid
 dq syscall_sigsuspend
 dq syscall_sigtimedwait
 dq syscall_sigpending
-syscallcount equ 91
+dq syscall_killthread
+syscallcount equ 92
 section .text
 global arch_syscall_entry
 ; on entry:
diff --git a/kernel-src/arch/x86-64/syscalllog.c b/kernel-src/arch/x86-64/syscalllog.c
index d7814836..014590de 100644
--- a/kernel-src/arch/x86-64/syscalllog.c
+++ b/kernel-src/arch/x86-64/syscalllog.c
@@ -5,7 +5,7 @@
 
 #ifdef SYSCALL_LOGGING
 
-#define SYSCALL_COUNT 91
+#define SYSCALL_COUNT 92
 #define LOGSTR(x) arch_e9_puts(x)
 
 static char *name[] = {
@@ -99,7 +99,8 @@ static char *name[] = {
 	"setegid",
 	"sigsuspend",
 	"sigtimedwait",
-	"sigpending"
+	"sigpending",
+	"killthread"
 };
 
 static char *args[] = {
@@ -193,7 +194,8 @@ static char *args[] = {
 	"egid %d", // setegid
 	"sigset %p", // sigsuspend
 	"sigset %p info %p, timespec %p", // sigtimedwait
-	"sigset %p\n" // sigpending
+	"sigset %p\n", // sigpending
+	"pid %d tid %d signal %d" // killthread
 };
 
 #endif
diff --git a/kernel-src/sys/syscalls/killthread.c b/kernel-src/sys/syscalls/killthread.c
new file mode 100644
index 00000000..543ae135
--- /dev/null
+++ b/kernel-src/sys/syscalls/killthread.c
@@ -0,0 +1,58 @@
+#include <kernel/syscalls.h>
+#include <arch/cpu.h>
+#include <logging.h>
+#include <kernel/jobctl.h>
+#include <kernel/auth.h>
+
+syscallret_t syscall_killthread(context_t *context, int pid, int tid, int signal) {
+	syscallret_t ret = {
+		.ret = -1
+	};
+
+	if (pid < 1 || tid < 1 || signal < 0 || signal > NSIG) {
+		ret.errno = EINVAL;
+		return ret;
+	}
+
+	proc_t *sender = _cpu()->thread->proc;
+	proc_t *target = sched_getprocfrompid(pid);
+	if (target == NULL) {
+		ret.errno = ESRCH;
+		return ret;
+	}
+
+	// permission check
+	if (signal != SIGCONT || jobctl_getpgid(target) != jobctl_getpgid(sender)) {
+		ret.errno = auth_process_check(&sender->cred, AUTH_ACTIONS_PROCESS_SIGNAL, target);
+		if (ret.errno)
+			goto leave;
+	}
+
+	bool ok = false;
+	bool intstatus = spinlock_acquireirqclear(&target->threadlistlock);
+
+	thread_t *thread = target->threadlist;
+	while (thread) {
+		if (thread->tid == tid) {
+			signal_signalthread(thread, signal, false);
+			ok = true;
+			break;
+		}
+
+		thread = thread->procnext;
+	}
+
+	spinlock_releaseirqrestore(&target->threadlistlock, intstatus);
+
+	if (ok == false) {
+		ret.errno = ESRCH;
+		ret.ret = -1;
+	} else {
+		ret.errno = 0;
+		ret.ret = 0;
+	}
+
+	leave:
+	PROC_RELEASE(target);
+	return ret;
+}
diff --git a/patches/mlibc/jinx-working-patch.patch b/patches/mlibc/jinx-working-patch.patch
index 065bc873..d20dae72 100644
--- a/patches/mlibc/jinx-working-patch.patch
+++ b/patches/mlibc/jinx-working-patch.patch
@@ -221,10 +221,10 @@ index 0000000..e5b087a
 +
 diff --git mlibc-workdir/sysdeps/astral/generic/generic.cpp mlibc-workdir/sysdeps/astral/generic/generic.cpp
 new file mode 100644
-index 0000000..1ce2424
+index 0000000..b73c420
 --- /dev/null
 +++ mlibc-workdir/sysdeps/astral/generic/generic.cpp
-@@ -0,0 +1,1002 @@
+@@ -0,0 +1,1007 @@
 +#include <bits/ensure.h>
 +#include <mlibc/debug.hpp>
 +#include <mlibc/all-sysdeps.hpp>
@@ -299,6 +299,11 @@ index 0000000..1ce2424
 +		return 0;
 +	}
 +
++	int sys_tgkill(int pid, int tid, int sig) {
++		long ret;
++		return syscall(SYSCALL_KILLTHREAD, &ret, pid, tid, sig);
++	}
++
 +	int sys_sigpending(sigset_t *set) {
 +		long ret;
 +		return syscall(SYSCALL_SIGPENDING, &ret, (uint64_t)set);
@@ -1246,10 +1251,10 @@ index 0000000..990eca0
 +#endif
 diff --git mlibc-workdir/sysdeps/astral/include/astral/syscall.h mlibc-workdir/sysdeps/astral/include/astral/syscall.h
 new file mode 100644
-index 0000000..058d486
+index 0000000..4d603e8
 --- /dev/null
 +++ mlibc-workdir/sysdeps/astral/include/astral/syscall.h
-@@ -0,0 +1,114 @@
+@@ -0,0 +1,115 @@
 +#ifndef _SYSCALL_H_INCLUDE
 +#define _SYSCALL_H_INCLUDE
 +
@@ -1344,6 +1349,7 @@ index 0000000..058d486
 +#define SYSCALL_SIGSUSPEND 88
 +#define SYSCALL_SIGTIMEDWAIT 89
 +#define SYSCALL_SIGPENDING 90
++#define SYSCALL_KILLTHREAD 91
 +
 +#include <stddef.h>
 +#include <stdint.h>