From: Alan Cox <alan@linux.intel.com>
Date: Mon, 2 Apr 2018 22:01:15 +0000 (+0100)
Subject: signals: fix signal leak by pushing back a pending signal when we recalc
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=f8a13d22ec4ffe63845f2359cd7b501893144d27;p=FUZIX.git

signals: fix signal leak by pushing back a pending signal when we recalc
---

diff --git a/Kernel/include/kernel.h b/Kernel/include/kernel.h
index 889a6c0a..ec54b02f 100644
--- a/Kernel/include/kernel.h
+++ b/Kernel/include/kernel.h
@@ -920,6 +920,7 @@ extern ptptr getproc(void);
 extern void newproc(ptptr p);
 extern ptptr ptab_alloc(void);
 extern void ssig(ptptr proc, uint8_t sig);
+extern void recalc_cursig(void);
 extern uint8_t chksigs(void);
 extern void program_vectors(uint16_t *pageptr);
 extern void sgrpsig(uint16_t pgrp, uint8_t sig);
diff --git a/Kernel/process.c b/Kernel/process.c
index 6728bed6..051f5d78 100644
--- a/Kernel/process.c
+++ b/Kernel/process.c
@@ -550,8 +550,22 @@ static const uint16_t clear =
 	SIGBIT(SIGCHLD) | SIGBIT(SIGURG) | SIGBIT(SIGWINCH) | SIGBIT(SIGIO) |
 	SIGBIT(SIGCONT);
 
-/* Process a block of 16 signals so we can avoid using longs */
+/* Put back a computed signal so that we can recalculate what needs to be
+   serviced correctly */
+void recalc_cursig(void)
+{
+	if (udata.u_cursig) {
+		struct sigbits *sb = udata.u_ptab->p_sig;
+		if (udata.u_cursig & 16) {
+			sb++;
+			udata.u_cursig &= ~16;
+		}
+		sb->s_pending |= 1 << udata.u_cursig;
+		udata.u_cursig = 0;
+	}
+}
 
+/* Process a block of 16 signals so we can avoid using longs */
 static uint8_t chksigset(struct sigbits *sb, uint8_t b)
 {
 	uint8_t j = 1;
@@ -641,8 +655,10 @@ uint8_t chksigs(void)
 	/* Sleeping without signals allowed. We rely upon the fact that
 	   P_IOWAIT is never pre-empted or returns to user space so
 	   udata.u_cursig is not consulted until it is safe to do so */
-	if (udata.u_ptab->p_status == P_IOWAIT)
+	if (udata.u_ptab->p_status == P_IOWAIT) {
+		recalc_cursig();
 		return 0;
+	}
 
 	/* Fast path - no signals pending means no work.
 	   Cursig being set means we've already worked out what to do.
diff --git a/Kernel/syscall_proc.c b/Kernel/syscall_proc.c
index 441fb575..de246491 100644
--- a/Kernel/syscall_proc.c
+++ b/Kernel/syscall_proc.c
@@ -479,7 +479,7 @@ arg_t _signal(void)
 	if (sig != SIGKILL && sig != SIGSTOP)
 		udata.u_sigvec[sig] = func;
 	/* Force recalculation of signal pending in the syscall return path */
-	udata.u_cursig = 0;
+	recalc_cursig();;
 	irqrestore(irq);
 	
 	return (retval);
@@ -514,7 +514,7 @@ arg_t _sigdisp(void)
 	else
 		sb->s_held &= ~sigmask(sig);
 	/* Force recalculation of signal pending in the syscall return path */
-	udata.u_cursig = 0;
+	recalc_cursig();
 	return 0;
 }