From: Theodore Tso <tytso@mit.edu>
Date: Tue, 18 Apr 1995 21:51:11 +0000 (+0000)
Subject: kpropd uses fork instead of vfork, because it's closing file
X-Git-Tag: krb5-1.0-beta5~368
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=ca05cace316acdb0ea7677a6ddc83610697f2b24;p=krb5.git

kpropd uses fork instead of vfork, because it's closing file
descriptors in the child.

Print out the pid of the child process if debugging is enabled.

Use _exit() instead exit() after a fork(), so that child process
doesn't cause the stdio buffers don't get flushed twice.

When debugging is enabled and kpropd can't bind to the port, it should
try binding again after setting SO_REUSEADDR on the socket.  This
avoids problems when debugging modifications to kprop/kpropd or its
setup, when kpropd is run twice quickly in succession.

kpropd shouldn't signal(SIGCHLD, SIG_IGN) in the parent.  Instead, it
should wait() until the child exits.  This was causing problems
because setting SIGCHLD to SIG_IGN under SYSV causes child processes
to get reaped automatically, so the wait() for kdb5_edit was failing.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@5368 dc483132-0cff-0310-8789-dd5450dbe970
---

diff --git a/src/slave/ChangeLog b/src/slave/ChangeLog
index 5b1285eaf..617728b0f 100644
--- a/src/slave/ChangeLog
+++ b/src/slave/ChangeLog
@@ -1,3 +1,27 @@
+Fri Apr 14 15:23:29 1995    <tytso@rsx-11.mit.edu>
+
+	* kpropd.c (load_database): kpropd uses fork instead of vfork,
+		because it's closing file descriptors in the child.
+
+		Print out the pid of the child process if debugging is
+		enabled. 
+
+		Use _exit() instead exit() after a fork(), so that child
+		process doesn't cause the stdio buffers don't get flushed
+		twice.
+
+		When debugging is enabled and kpropd can't bind to the
+		port, it should try binding again after setting
+		SO_REUSEADDR on the socket.  This avoids problems when
+		debugging modifications to kprop/kpropd or its setup, when
+		kpropd is run twice quickly in succession. 
+
+		kpropd shouldn't signal(SIGCHLD, SIG_IGN) in the parent.
+		Instead, it should wait() until the child exits.  This was
+		causing problems because setting SIGCHLD to SIG_IGN under
+		SYSV causes child processes to get reaped automatically,
+		so the wait() for kdb5_edit was failing.
+
 Mon Mar 27 07:56:26 1995 Chris Provenzano (proven@mit.edu)
 
         * kprop.c : Use new calling conventions for krb5_sendauth(),
diff --git a/src/slave/kpropd.c b/src/slave/kpropd.c
index d0872df29..174024d5c 100644
--- a/src/slave/kpropd.c
+++ b/src/slave/kpropd.c
@@ -138,6 +138,7 @@ void do_standalone()
 	struct	sockaddr_in	sin, frominet;
 	struct servent *sp;
 	int	finet, fromlen, s;
+	int	ret;
 	
 	finet = socket(AF_INET, SOCK_STREAM, 0);
 	if (finet < 0) {
@@ -152,10 +153,22 @@ void do_standalone()
 	memset((char *) &sin,0, sizeof(sin));
 	sin.sin_family = AF_INET;
 	sin.sin_port = sp->s_port;
-	if (bind(finet, (struct sockaddr *) &sin, sizeof(sin)) < 0) {
+	if ((ret = bind(finet, (struct sockaddr *) &sin, sizeof(sin))) < 0) {
+	    if (debug) {
+		int on = 1;
+		fprintf(stderr,
+			"%s: attempting to rebind socket with SO_REUSEADDR\n",
+			progname);
+		if (setsockopt(finet, SOL_SOCKET, SO_REUSEADDR,
+			       (char *)&on, sizeof(on)) < 0)
+		    com_err(progname, errno, "in setsockopt(SO_REUSEADDR)");
+		ret = bind(finet, (struct sockaddr *) &sin, sizeof(sin));
+	    }
+	    if (ret < 0) {
 		perror("bind");
 		com_err(progname, errno, "while binding listener socket");
 		exit(1);
+	    }
 	}
 	if (!debug)
 		daemon(1, 0);	    
@@ -172,6 +185,8 @@ void do_standalone()
 		exit(1);
 	}
 	while (1) {
+		int child_pid;
+	    
 		memset((char *)&frominet, 0, sizeof(frominet));
 		fromlen = sizeof(frominet);
 		s = accept(finet, (struct sockaddr *) &frominet, &fromlen);
@@ -182,15 +197,25 @@ void do_standalone()
 					"from accept system call");
 			continue;
 		}
-		if (debug || fork() == 0) {
-			(void) signal(SIGCHLD, SIG_IGN);
+		if (debug)
+			child_pid = 0;
+		else
+			child_pid = fork();
+		switch (child_pid) {
+		case -1:
+			com_err(progname, errno, "while forking");
+			exit(1);
+		case 0:
 			(void) close(finet);
 
 			doit(s);
 			close(s);
-			exit(0);
+			_exit(0);
+		default:
+			wait(0);
+			close(s);
+			
 		}
-		close(s);
 	}
 }
 
@@ -749,6 +774,7 @@ load_database(context, kdb5_edit, database_file_name)
 {
 	static char	*edit_av[4];
 	int	error_ret, save_stderr;
+	int	child_pid;
 
 	/* <sys/param.h> has been included, so BSD will be defined on
 	   BSD systems */
@@ -773,10 +799,7 @@ load_database(context, kdb5_edit, database_file_name)
 	edit_av[2] = request;
 	edit_av[3] = NULL;
 
-#ifndef BSD
-#define	vfork fork
-#endif
-	switch(vfork()) {
+	switch(child_pid = fork()) {
 	case -1:
 		com_err(progname, errno, "while trying to fork %s",
 			kdb5_edit);
@@ -798,9 +821,11 @@ load_database(context, kdb5_edit, database_file_name)
 			dup2(save_stderr, 2);
 		com_err(progname, retval, "while trying to exec %s",
 			kdb5_edit);
-		exit(1);
+		_exit(1);
 		/*NOTREACHED*/
 	default:
+		if (debug)
+		    printf("Child PID is %d\n", child_pid);
 		if (wait(&waitb) < 0) {
 			com_err(progname, errno, "while waiting for %s",
 				kdb5_edit);