syscalls: killthread

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:

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

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;
+}