From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file

---
 kernel/include/linux/sched/signal.h |  189 ++++++++++++++++++++++++++++-------------------
 1 files changed, 113 insertions(+), 76 deletions(-)

diff --git a/kernel/include/linux/sched/signal.h b/kernel/include/linux/sched/signal.h
index 9c456c7..fb0b389 100644
--- a/kernel/include/linux/sched/signal.h
+++ b/kernel/include/linux/sched/signal.h
@@ -8,6 +8,10 @@
 #include <linux/sched/jobctl.h>
 #include <linux/sched/task.h>
 #include <linux/cred.h>
+#include <linux/refcount.h>
+#include <linux/posix-timers.h>
+#include <linux/mm_types.h>
+#include <asm/ptrace.h>
 #include <linux/android_kabi.h>
 
 /*
@@ -15,10 +19,10 @@
  */
 
 struct sighand_struct {
-	atomic_t		count;
-	struct k_sigaction	action[_NSIG];
 	spinlock_t		siglock;
+	refcount_t		count;
 	wait_queue_head_t	signalfd_wqh;
+	struct k_sigaction	action[_NSIG];
 };
 
 /*
@@ -56,18 +60,12 @@
 /**
  * struct thread_group_cputimer - thread group interval timer counts
  * @cputime_atomic:	atomic thread group interval timers.
- * @running:		true when there are timers running and
- *			@cputime_atomic receives updates.
- * @checking_timer:	true when a thread in the group is in the
- *			process of checking for thread group timers.
  *
  * This structure contains the version of task_cputime, above, that is
  * used for thread group CPU timer calculations.
  */
 struct thread_group_cputimer {
 	struct task_cputime_atomic cputime_atomic;
-	bool running;
-	bool checking_timer;
 };
 
 struct multiprocess_signals {
@@ -83,7 +81,7 @@
  * the locking of signal_struct.
  */
 struct signal_struct {
-	atomic_t		sigcnt;
+	refcount_t		sigcnt;
 	atomic_t		live;
 	int			nr_threads;
 	struct list_head	thread_head;
@@ -148,12 +146,9 @@
 	 */
 	struct thread_group_cputimer cputimer;
 
-	/* Earliest-expiration cache. */
-	struct task_cputime cputime_expires;
-
-	struct list_head cpu_timers[3];
-
 #endif
+	/* Empty if CONFIG_POSIX_TIMERS=n */
+	struct posix_cputimers posix_cputimers;
 
 	/* PID/PID hash table linkage. */
 	struct pid *pids[PIDTYPE_MAX];
@@ -232,7 +227,16 @@
 
 	struct mutex cred_guard_mutex;	/* guard against foreign influences on
 					 * credential calculations
-					 * (notably. ptrace) */
+					 * (notably. ptrace)
+					 * Deprecated do not use in new code.
+					 * Use exec_update_lock instead.
+					 */
+	struct rw_semaphore exec_update_lock;	/* Held while task_struct is
+						 * being updated during exec,
+						 * and may have inconsistent
+						 * permissions.
+						 */
+
 	ANDROID_KABI_RESERVE(1);
 	ANDROID_KABI_RESERVE(2);
 	ANDROID_KABI_RESERVE(3);
@@ -275,17 +279,18 @@
 extern void flush_signals(struct task_struct *);
 extern void ignore_signals(struct task_struct *);
 extern void flush_signal_handlers(struct task_struct *, int force_default);
-extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);
+extern int dequeue_signal(struct task_struct *task,
+			  sigset_t *mask, kernel_siginfo_t *info);
 
-static inline int kernel_dequeue_signal(siginfo_t *info)
+static inline int kernel_dequeue_signal(void)
 {
-	struct task_struct *tsk = current;
-	siginfo_t __info;
+	struct task_struct *task = current;
+	kernel_siginfo_t __info;
 	int ret;
 
-	spin_lock_irq(&tsk->sighand->siglock);
-	ret = dequeue_signal(tsk, &tsk->blocked, info ?: &__info);
-	spin_unlock_irq(&tsk->sighand->siglock);
+	spin_lock_irq(&task->sighand->siglock);
+	ret = dequeue_signal(task, &task->blocked, &__info);
+	spin_unlock_irq(&task->sighand->siglock);
 
 	return ret;
 }
@@ -310,16 +315,19 @@
 # define ___ARCH_SI_IA64(_a1, _a2, _a3)
 #endif
 
-int force_sig_fault(int sig, int code, void __user *addr
+int force_sig_fault_to_task(int sig, int code, void __user *addr
 	___ARCH_SI_TRAPNO(int trapno)
 	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
 	, struct task_struct *t);
+int force_sig_fault(int sig, int code, void __user *addr
+	___ARCH_SI_TRAPNO(int trapno)
+	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr));
 int send_sig_fault(int sig, int code, void __user *addr
 	___ARCH_SI_TRAPNO(int trapno)
 	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
 	, struct task_struct *t);
 
-int force_sig_mceerr(int code, void __user *, short, struct task_struct *);
+int force_sig_mceerr(int code, void __user *, short);
 int send_sig_mceerr(int code, void __user *, short, struct task_struct *);
 
 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper);
@@ -327,18 +335,18 @@
 
 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
 
-extern int send_sig_info(int, struct siginfo *, struct task_struct *);
-extern void force_sigsegv(int sig, struct task_struct *p);
-extern int force_sig_info(int, struct siginfo *, struct task_struct *);
-extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
-extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
-extern int kill_pid_info_as_cred(int, struct siginfo *, struct pid *,
+extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
+extern void force_sigsegv(int sig);
+extern int force_sig_info(struct kernel_siginfo *);
+extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
+extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
+extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
 				const struct cred *);
 extern int kill_pgrp(struct pid *pid, int sig, int priv);
 extern int kill_pid(struct pid *pid, int sig, int priv);
 extern __must_check bool do_notify_parent(struct task_struct *, int);
 extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent);
-extern void force_sig(int, struct task_struct *);
+extern void force_sig(int);
 extern int send_sig(int, struct task_struct *, int);
 extern int zap_other_threads(struct task_struct *p);
 extern struct sigqueue *sigqueue_alloc(void);
@@ -352,9 +360,21 @@
 	return -ERESTARTNOINTR;
 }
 
-static inline int signal_pending(struct task_struct *p)
+static inline int task_sigpending(struct task_struct *p)
 {
 	return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
+}
+
+static inline int signal_pending(struct task_struct *p)
+{
+	/*
+	 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
+	 * behavior in terms of ensuring that we break out of wait loops
+	 * so that notify signal callbacks can be processed.
+	 */
+	if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
+		return 1;
+	return task_sigpending(p);
 }
 
 static inline int __fatal_signal_pending(struct task_struct *p)
@@ -364,7 +384,7 @@
 
 static inline int fatal_signal_pending(struct task_struct *p)
 {
-	return signal_pending(p) && __fatal_signal_pending(p);
+	return task_sigpending(p) && __fatal_signal_pending(p);
 }
 
 static inline int signal_pending_state(long state, struct task_struct *p)
@@ -375,6 +395,20 @@
 		return 0;
 
 	return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
+}
+
+/*
+ * This should only be used in fault handlers to decide whether we
+ * should stop the current fault routine to handle the signals
+ * instead, especially with the case where we've got interrupted with
+ * a VM_FAULT_RETRY.
+ */
+static inline bool fault_signal_pending(vm_fault_t fault_flags,
+					struct pt_regs *regs)
+{
+	return unlikely((fault_flags & VM_FAULT_RETRY) &&
+			(fatal_signal_pending(current) ||
+			 (user_mode(regs) && signal_pending(current))));
 }
 
 /*
@@ -420,21 +454,20 @@
 static inline void set_restore_sigmask(void)
 {
 	set_thread_flag(TIF_RESTORE_SIGMASK);
-	WARN_ON(!test_thread_flag(TIF_SIGPENDING));
 }
 
-static inline void clear_tsk_restore_sigmask(struct task_struct *tsk)
+static inline void clear_tsk_restore_sigmask(struct task_struct *task)
 {
-	clear_tsk_thread_flag(tsk, TIF_RESTORE_SIGMASK);
+	clear_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
 }
 
 static inline void clear_restore_sigmask(void)
 {
 	clear_thread_flag(TIF_RESTORE_SIGMASK);
 }
-static inline bool test_tsk_restore_sigmask(struct task_struct *tsk)
+static inline bool test_tsk_restore_sigmask(struct task_struct *task)
 {
-	return test_tsk_thread_flag(tsk, TIF_RESTORE_SIGMASK);
+	return test_tsk_thread_flag(task, TIF_RESTORE_SIGMASK);
 }
 static inline bool test_restore_sigmask(void)
 {
@@ -451,11 +484,10 @@
 static inline void set_restore_sigmask(void)
 {
 	current->restore_sigmask = true;
-	WARN_ON(!test_thread_flag(TIF_SIGPENDING));
 }
-static inline void clear_tsk_restore_sigmask(struct task_struct *tsk)
+static inline void clear_tsk_restore_sigmask(struct task_struct *task)
 {
-	tsk->restore_sigmask = false;
+	task->restore_sigmask = false;
 }
 static inline void clear_restore_sigmask(void)
 {
@@ -465,9 +497,9 @@
 {
 	return current->restore_sigmask;
 }
-static inline bool test_tsk_restore_sigmask(struct task_struct *tsk)
+static inline bool test_tsk_restore_sigmask(struct task_struct *task)
 {
-	return tsk->restore_sigmask;
+	return task->restore_sigmask;
 }
 static inline bool test_and_clear_restore_sigmask(void)
 {
@@ -484,6 +516,16 @@
 		__set_current_blocked(&current->saved_sigmask);
 }
 
+extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
+
+static inline void restore_saved_sigmask_unless(bool interrupted)
+{
+	if (interrupted)
+		WARN_ON(!signal_pending(current));
+	else
+		restore_saved_sigmask();
+}
+
 static inline sigset_t *sigmask_to_save(void)
 {
 	sigset_t *res = &current->blocked;
@@ -498,9 +540,19 @@
 }
 
 /* These can be the second arg to send_sig_info/send_group_sig_info.  */
-#define SEND_SIG_NOINFO ((struct siginfo *) 0)
-#define SEND_SIG_PRIV	((struct siginfo *) 1)
-#define SEND_SIG_FORCED	((struct siginfo *) 2)
+#define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
+#define SEND_SIG_PRIV	((struct kernel_siginfo *) 1)
+
+static inline int __on_sig_stack(unsigned long sp)
+{
+#ifdef CONFIG_STACK_GROWSUP
+	return sp >= current->sas_ss_sp &&
+		sp - current->sas_ss_sp < current->sas_ss_size;
+#else
+	return sp > current->sas_ss_sp &&
+		sp - current->sas_ss_sp <= current->sas_ss_size;
+#endif
+}
 
 /*
  * True if we are on the alternate signal stack.
@@ -519,13 +571,7 @@
 	if (current->sas_ss_flags & SS_AUTODISARM)
 		return 0;
 
-#ifdef CONFIG_STACK_GROWSUP
-	return sp >= current->sas_ss_sp &&
-		sp - current->sas_ss_sp < current->sas_ss_size;
-#else
-	return sp > current->sas_ss_sp &&
-		sp - current->sas_ss_sp <= current->sas_ss_size;
-#endif
+	return __on_sig_stack(sp);
 }
 
 static inline int sas_ss_flags(unsigned long sp)
@@ -622,25 +668,14 @@
 	return task->signal->pids[PIDTYPE_SID];
 }
 
-static inline int get_nr_threads(struct task_struct *tsk)
+static inline int get_nr_threads(struct task_struct *task)
 {
-	return tsk->signal->nr_threads;
+	return task->signal->nr_threads;
 }
 
 static inline bool thread_group_leader(struct task_struct *p)
 {
 	return p->exit_signal >= 0;
-}
-
-/* Do to the insanities of de_thread it is possible for a process
- * to have the pid of the thread group leader without actually being
- * the thread group leader.  For iteration through the pids in proc
- * all we care about is that we have a task with the appropriate
- * pid, we don't actually care if we have the right task.
- */
-static inline bool has_group_leader_pid(struct task_struct *p)
-{
-	return task_pid(p) == task_tgid(p);
 }
 
 static inline
@@ -663,35 +698,37 @@
 #define delay_group_leader(p) \
 		(thread_group_leader(p) && !thread_group_empty(p))
 
-extern struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
+extern bool thread_group_exited(struct pid *pid);
+
+extern struct sighand_struct *__lock_task_sighand(struct task_struct *task,
 							unsigned long *flags);
 
-static inline struct sighand_struct *lock_task_sighand(struct task_struct *tsk,
+static inline struct sighand_struct *lock_task_sighand(struct task_struct *task,
 						       unsigned long *flags)
 {
 	struct sighand_struct *ret;
 
-	ret = __lock_task_sighand(tsk, flags);
-	(void)__cond_lock(&tsk->sighand->siglock, ret);
+	ret = __lock_task_sighand(task, flags);
+	(void)__cond_lock(&task->sighand->siglock, ret);
 	return ret;
 }
 
-static inline void unlock_task_sighand(struct task_struct *tsk,
+static inline void unlock_task_sighand(struct task_struct *task,
 						unsigned long *flags)
 {
-	spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
+	spin_unlock_irqrestore(&task->sighand->siglock, *flags);
 }
 
-static inline unsigned long task_rlimit(const struct task_struct *tsk,
+static inline unsigned long task_rlimit(const struct task_struct *task,
 		unsigned int limit)
 {
-	return READ_ONCE(tsk->signal->rlim[limit].rlim_cur);
+	return READ_ONCE(task->signal->rlim[limit].rlim_cur);
 }
 
-static inline unsigned long task_rlimit_max(const struct task_struct *tsk,
+static inline unsigned long task_rlimit_max(const struct task_struct *task,
 		unsigned int limit)
 {
-	return READ_ONCE(tsk->signal->rlim[limit].rlim_max);
+	return READ_ONCE(task->signal->rlim[limit].rlim_max);
 }
 
 static inline unsigned long rlimit(unsigned int limit)

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