svn commit: r208489 - head/bin/sh

[Jilles Tjoelker]

Author: jilles
Date: Mon May 24 10:35:57 2010
New Revision: 208489
URL: http://svn.freebsd.org/changeset/base/208489

Log:
  sh: Reap any zombies before forking for a background command.
  
  This prevents accumulating huge amounts of zombies if a script executes
  many background commands but no external commands or subshells.
  
  Note that zombies will not be reaped during long calculations (within
  the shell process) or read builtins, but those actions do not create
  more zombies.
  
  The terminated background commands will also still be remembered by the
  shell.
  
  PR:		bin/55346

Modified:
  head/bin/sh/jobs.c

Modified: head/bin/sh/jobs.c
==============================================================================
--- head/bin/sh/jobs.c	Mon May 24 10:23:49 2010	(r208488)
+++ head/bin/sh/jobs.c	Mon May 24 10:35:57 2010	(r208489)
@@ -91,6 +91,7 @@ STATIC void freejob(struct job *);
 STATIC struct job *getjob(char *);
 STATIC pid_t dowait(int, struct job *);
 STATIC pid_t waitproc(int, int *);
+STATIC void checkzombies(void);
 STATIC void cmdtxt(union node *);
 STATIC void cmdputs(const char *);
 #if JOBS
@@ -400,7 +401,7 @@ showjobs(int change, int mode)
 	struct job *jp;
 
 	TRACE(("showjobs(%d) called\n", change));
-	while (dowait(0, (struct job *)NULL) > 0);
+	checkzombies();
 	for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
 		if (! jp->used)
 			continue;
@@ -742,6 +743,8 @@ forkshell(struct job *jp, union node *n,
 	TRACE(("forkshell(%%%d, %p, %d) called\n", jp - jobtab, (void *)n,
 	    mode));
 	INTOFF;
+	if (mode == FORK_BG)
+		checkzombies();
 	flushall();
 	pid = fork();
 	if (pid == -1) {
@@ -1056,6 +1059,15 @@ stoppedjobs(void)
 	return (0);
 }
 
+
+STATIC void
+checkzombies(void)
+{
+	while (njobs > 0 && dowait(0, NULL) > 0)
+		;
+}
+
+
 /*
  * Return a string identifying a command (to be printed by the
  * jobs command.