eval: Reap zombies after built-in commands and functions

Commit Message

Herbert Xu March 26, 2018, 3:55 p.m. UTC

Currently dash does not reap dead children after built-in commands
or functions.  This means that if you construct a loop consisting
of solely built-in commands and functions, then zombies can hang
around indefinitely.

This patch fixes this by reaping when necessary after each built-in
command and function.

Reported-by: Denys Vlasenko <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

Patch

diff --git a/src/eval.c b/src/eval.c
index 7498f9d..19e06ec 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -848,6 +848,8 @@  bail:
 		goto out;
 	}
 
+	jp = NULL;
+
 	/* Execute the command. */
 	switch (cmdentry.cmdtype) {
 	default:
@@ -856,7 +858,6 @@  bail:
 			INTOFF;
 			jp = makejob(cmd, 1);
 			if (forkshell(jp, cmd, FORK_FG) != 0) {
-				status = waitforjob(jp);
 				INTON;
 				break;
 			}
@@ -875,22 +876,22 @@  bail:
 		if (evalbltin(cmdentry.u.cmd, argc, argv, flags)) {
 			if (exception == EXERROR && spclbltin <= 0) {
 				FORCEINTON;
-				goto readstatus;
+				break;
 			}
 raise:
 			longjmp(handler->loc, 1);
 		}
-		goto readstatus;
+		break;
 
 	case CMDFUNCTION:
 		poplocalvars(1);
 		if (evalfun(cmdentry.u.func, argc, argv, flags))
 			goto raise;
-readstatus:
-		status = exitstatus;
 		break;
 	}
 
+	status = waitforjob(jp);
+
 out:
 	if (cmd->ncmd.redirect)
 		popredir(execcmd);
diff --git a/src/jobs.c b/src/jobs.c
index f0d34ab..1a97c54 100644
--- a/src/jobs.c
+++ b/src/jobs.c
@@ -53,6 +53,7 @@ 
 #include <termios.h>
 #undef CEOF			/* syntax.h redefines this */
 #endif
+#include "eval.h"
 #include "redir.h"
 #include "show.h"
 #include "main.h"
@@ -973,10 +974,11 @@  waitforjob(struct job *jp)
 {
 	int st;
 
-	TRACE(("waitforjob(%%%d) called\n", jobno(jp)));
-	while (jp->state == JOBRUNNING) {
+	TRACE(("waitforjob(%%%d) called\n", jp ? jobno(jp) : 0));
+	while ((jp && jp->state == JOBRUNNING) || gotsigchld)
 		dowait(DOWAIT_BLOCK, jp);
-	}
+	if (!jp)
+		return exitstatus;
 	st = getstatus(jp);
 #if JOBS
 	if (jp->jobctl) {