bin/117603: [patch] dump(8) hangs on SMP - 4way and higher.

[Danny Braniss]

hi,
[latest follow up]
doing
	sigfillset(&s_mask);
	sigdelset(&s_mask, SIGUSR2);
takes care of unwanted signals.
so here is my latest proposed patch.

-------------- next part --------------
--- tape.c.orig	Wed Mar  2 04:30:08 2005
+++ tape.c	Sun Nov  4 13:42:55 2007
@@ -109,11 +109,6 @@
 
 int master;		/* pid of master, for sending error signals */
 int tenths;		/* length of tape used per block written */
-static volatile sig_atomic_t caught; /* have we caught the signal to proceed? */
-static volatile sig_atomic_t ready; /* reached the lock point without having */
-			/* received the SIGUSR2 signal from the prev slave? */
-static jmp_buf jmpbuf;	/* where to jump to if we are ready when the */
-			/* SIGUSR2 arrives from the previous slave */
 
 int
 alloctape(void)
@@ -685,15 +680,13 @@
 void
 proceed(int signo __unused)
 {
-
-	if (ready)
-		longjmp(jmpbuf, 1);
-	caught++;
+     // do nothing ...
 }
 
 void
 enslave(void)
 {
+	sigset_t	s_mask;
 	int cmd[2];
 	int i, j;
 
@@ -704,13 +697,11 @@
 	signal(SIGUSR1, tperror);    /* Slave sends SIGUSR1 on tape errors */
 	signal(SIGUSR2, proceed);    /* Slave sends SIGUSR2 to next slave */
 
-	for (i = 0; i < SLAVES; i++) {
-		if (i == slp - &slaves[0]) {
-			caught = 1;
-		} else {
-			caught = 0;
-		}
+	sigemptyset(&s_mask);
+	sigaddset(&s_mask, SIGUSR2);
+	sigprocmask(SIG_BLOCK, &s_mask, NULL);
 
+	for (i = 0; i < SLAVES; i++) {
 		if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 ||
 		    (slaves[i].pid = fork()) < 0)
 			quit("too many slaves, %d (recompile smaller): %s\n",
@@ -733,6 +724,7 @@
 		              sizeof slaves[0].pid);
 
 	master = 0;
+	kill(slp->pid, SIGUSR2); // start the ball rolling
 }
 
 void
@@ -757,6 +749,7 @@
 static void
 doslave(int cmd, int slave_number)
 {
+	sigset_t s_mask;
 	int nread;
 	int nextslave, size, wrote, eot_count;
 
@@ -774,7 +767,7 @@
 	    != sizeof nextslave) {
 		quit("master/slave protocol botched - didn't get pid of next slave.\n");
 	}
-
+	sigemptyset(&s_mask);
 	/*
 	 * Get list of blocks to dump, read the blocks into tape buffer
 	 */
@@ -793,14 +786,7 @@
 				       quit("master/slave protocol botched.\n");
 			}
 		}
-		if (setjmp(jmpbuf) == 0) {
-			ready = 1;
-			if (!caught)
-				(void) pause();
-		}
-		ready = 0;
-		caught = 0;
-
+		sigsuspend(&s_mask);
 		/* Try to write the data... */
 		eot_count = 0;
 		size = 0;