From 0146b318371360bda1f0efdd196d42417287e41c Mon Sep 17 00:00:00 2001
From: "K. Lange" <klange@toaruos.org>
Date: Fri, 24 Sep 2021 00:11:14 +0900
Subject: [PATCH] ptrace: Allow separate tracing of signals and syscalls

---
 base/usr/include/kernel/process.h |  4 +++-
 base/usr/include/sys/ptrace.h     |  3 ++-
 kernel/sys/ptrace.c               | 14 ++++++++++++--
 kernel/sys/signal.c               |  2 +-
 kernel/sys/syscall.c              |  4 ++--
 5 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/base/usr/include/kernel/process.h b/base/usr/include/kernel/process.h
index 3265c2e2..d57829b5 100644
--- a/base/usr/include/kernel/process.h
+++ b/base/usr/include/kernel/process.h
@@ -67,7 +67,9 @@ typedef struct file_descriptors {
 #define PROC_FLAG_RUNNING    0x08
 #define PROC_FLAG_SLEEP_INT  0x10
 #define PROC_FLAG_SUSPENDED  0x20
-#define PROC_FLAG_TRACED     0x40
+
+#define PROC_FLAG_TRACE_SYSCALLS     0x40
+#define PROC_FLAG_TRACE_SIGNALS      0x80
 
 typedef struct process {
 	pid_t id;    /* PID */
diff --git a/base/usr/include/sys/ptrace.h b/base/usr/include/sys/ptrace.h
index 60fe6da1..bffa1ffb 100644
--- a/base/usr/include/sys/ptrace.h
+++ b/base/usr/include/sys/ptrace.h
@@ -11,7 +11,8 @@ enum __ptrace_request {
 	PTRACE_DETACH,
 	PTRACE_TRACEME,
 	PTRACE_GETREGS,
-	PTRACE_PEEKDATA
+	PTRACE_PEEKDATA,
+	PTRACE_SIGNALS_ONLY_PLZ
 };
 
 enum __ptrace_event {
diff --git a/kernel/sys/ptrace.c b/kernel/sys/ptrace.c
index 0cb0852c..542d5315 100644
--- a/kernel/sys/ptrace.c
+++ b/kernel/sys/ptrace.c
@@ -16,7 +16,7 @@ long ptrace_attach(pid_t pid) {
 	process_t * tracee = process_from_pid(pid);
 	if (!tracee) return -ESRCH;
 	if (this_core->current_process->user != 0 && this_core->current_process->user != tracee->user) return -EPERM;
-	__sync_or_and_fetch(&tracee->flags, PROC_FLAG_TRACED);
+	__sync_or_and_fetch(&tracee->flags, (PROC_FLAG_TRACE_SYSCALLS | PROC_FLAG_TRACE_SIGNALS));
 	tracee->tracer = this_core->current_process->id;
 	send_signal(pid, SIGSTOP, 1);
 	return 0;
@@ -26,7 +26,7 @@ long ptrace_self(void) {
 	process_t * parent = process_get_parent((process_t*)this_core->current_process);
 	if (!parent) return -EINVAL;
 
-	__sync_or_and_fetch(&this_core->current_process->flags, PROC_FLAG_TRACED);
+	__sync_or_and_fetch(&this_core->current_process->flags, (PROC_FLAG_TRACE_SYSCALLS | PROC_FLAG_TRACE_SIGNALS));
 	this_core->current_process->tracer = parent->id;
 
 	return 0;
@@ -95,6 +95,14 @@ long ptrace_peek(pid_t pid, void * addr, void * data) {
 	return 0;
 }
 
+long ptrace_signals_only(pid_t pid) {
+	process_t * tracee = process_from_pid(pid);
+	if (!tracee || (tracee->tracer != this_core->current_process->id) || !(tracee->flags & PROC_FLAG_SUSPENDED)) return -ESRCH;
+	__sync_and_and_fetch(&tracee->flags, ~(PROC_FLAG_TRACE_SYSCALLS));
+	return 0;
+}
+
+
 long ptrace_handle(long request, pid_t pid, void * addr, void * data) {
 	switch (request) {
 		case PTRACE_ATTACH:
@@ -107,6 +115,8 @@ long ptrace_handle(long request, pid_t pid, void * addr, void * data) {
 			return ptrace_continue(pid,(uintptr_t)data);
 		case PTRACE_PEEKDATA:
 			return ptrace_peek(pid,addr,data);
+		case PTRACE_SIGNALS_ONLY_PLZ:
+			return ptrace_signals_only(pid);
 		default:
 			return -EINVAL;
 	}
diff --git a/kernel/sys/signal.c b/kernel/sys/signal.c
index f72a3ef1..0ada653d 100644
--- a/kernel/sys/signal.c
+++ b/kernel/sys/signal.c
@@ -78,7 +78,7 @@ void handle_signal(process_t * proc, signal_t * sig) {
 	free(sig);
 
 	/* Are we being traced? */
-	if (this_core->current_process->flags & PROC_FLAG_TRACED) {
+	if (this_core->current_process->flags & PROC_FLAG_TRACE_SIGNALS) {
 		signum = ptrace_signal(signum, 0);
 	}
 
diff --git a/kernel/sys/syscall.c b/kernel/sys/syscall.c
index 0c4d1e87..195be8f7 100644
--- a/kernel/sys/syscall.c
+++ b/kernel/sys/syscall.c
@@ -1138,7 +1138,7 @@ void syscall_handler(struct regs * r) {
 	scall_func func = syscalls[arch_syscall_number(r)];
 	this_core->current_process->syscall_registers = r;
 
-	if (this_core->current_process->flags & PROC_FLAG_TRACED) {
+	if (this_core->current_process->flags & PROC_FLAG_TRACE_SYSCALLS) {
 		ptrace_signal(SIGTRAP, PTRACE_EVENT_SYSCALL_ENTER);
 	}
 
@@ -1146,7 +1146,7 @@ void syscall_handler(struct regs * r) {
 		arch_syscall_arg0(r), arch_syscall_arg1(r), arch_syscall_arg2(r),
 		arch_syscall_arg3(r), arch_syscall_arg4(r)));
 
-	if (this_core->current_process->flags & PROC_FLAG_TRACED) {
+	if (this_core->current_process->flags & PROC_FLAG_TRACE_SYSCALLS) {
 		ptrace_signal(SIGTRAP, PTRACE_EVENT_SYSCALL_EXIT);
 	}
 }