From: Matthias Kruk <m@m10k.eu>
Date: Sun, 5 Jan 2020 07:55:54 +0000 (+0900)
Subject: Deliver a POSIX signal to a process that has caused an exception
X-Git-Url: https://git.corax.cc/?a=commitdiff_plain;h=ca81cd4e572c07526e8064599d17f4785a496773;p=corax

Deliver a POSIX signal to a process that has caused an exception
---

diff --git a/kernel/arch/interrupt.c b/kernel/arch/interrupt.c
index 53ff677..6aaf88a 100644
--- a/kernel/arch/interrupt.c
+++ b/kernel/arch/interrupt.c
@@ -27,6 +27,7 @@
 #include "defs.h"
 
 extern void pg_fault_debug(pg_dir_t*, void*);
+extern void _task_sig_stub();
 
 void sched_tick(void);
 extern int sys_cxnet(long, long, long, long, long, long, long);
@@ -47,6 +48,29 @@ extern void _apic_eoi(u32_t);
 extern void _i8259_eoi(u32_t);
 #endif /* CONFIG_APIC */
 
+void task_signal_deliver(task_t *task, stack_frame_t *stk, int signum)
+{
+	struct {
+		void *eip;
+		void *handler;
+		int signal;
+		void *data;
+		siginfo_t si;
+	} __attribute__((packed)) stkfrm;
+
+	stkfrm.data = NULL;
+	stkfrm.signal = signum;
+	stkfrm.eip = (void*)stk->eip;
+	stkfrm.handler = process_get_sighandler((process_t*)task->t_proc, signum);
+	stk->eip = (u32_t)_task_sig_stub;
+	stk->prevesp -= sizeof(stkfrm);
+
+	/* copy the data onto the user-mode stack */
+	process_memcpy_ktop((process_t*)task->t_proc, (void*)stk->prevesp, &stkfrm, sizeof(stkfrm));
+
+	return;
+}
+
 void _int_handle(stack_frame_t ctx)
 {
     switch(ctx.intn) {
@@ -107,8 +131,10 @@ void _int_handle(stack_frame_t ctx)
 void _exc_handle(stack_frame_t ctx)
 {
 	process_t *cproc;
+	task_t *ctask;
 
-	cproc = process_get_current();
+	ctask = task_get_current();
+	cproc = (process_t*)ctask->t_proc;
 
 	if(ctx.cs == KERNEL_CODE) {
 		/* kernel bug */
@@ -137,6 +163,22 @@ void _exc_handle(stack_frame_t ctx)
 
 		int sig;
 
+		dbg_printf("User-mode exception %u at 0x%08x\n", ctx.intn, ctx.eip);
+
+		if(ctx.intn == EXC_PAGEFAULT) {
+			u32_t cr2;
+			pg_dir_t *pd;
+
+			asm volatile("movl %%cr2, %%eax; movl %%eax, %0" : "=r"(cr2));
+			dbg_printf("CR2: 0x%08x\n", cr2);
+
+			if(process_get_pagedir(cproc, &pd) == 0) {
+				pg_fault_debug(pd, (void*)cr2);
+			}
+			for(;;);
+		}
+
+
 		switch(ctx.intn) {
 		default:
 		case EXC_DEBUG:
@@ -170,10 +212,9 @@ void _exc_handle(stack_frame_t ctx)
 		}
 
 		/*
-		 * Deliver the signal to the current process. The process_signal_deliver()
-		 * function will make sure that the signal is handled by the current task.
+		 * Deliver the signal to the currently executing task
 		 */
-		process_signal_deliver(cproc, sig);
+		task_signal_deliver(ctask, &ctx, sig);
 	}
 
     return;
diff --git a/kernel/include/arch.h b/kernel/include/arch.h
index 29c8804..9917ea4 100644
--- a/kernel/include/arch.h
+++ b/kernel/include/arch.h
@@ -192,6 +192,8 @@ int     pg_dir_munmap(pg_dir_t*, void*, u32_t);
 u8_t    io_inb(const u16_t);
 void    io_outb(const u16_t, const u8_t);
 
+void    task_signal_deliver(task_t*, stack_frame_t*, int);
+
 #endif /* !__ASSEMBLY_SOURCE */
 
 #endif /* __ARCH_H */