32176: plug additional deadlock-inducing pipe descriptor leaks

4 files changed, 36 insertions, 14 deletions

diff --git a/ChangeLog b/ChangeLog
index c4760218e..9efa11950 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-12-21  Barton E. Schaefer  <schaefer@brasslantern.com>
+
+	* PWS + Bart: 32176: plug additional descriptor leaks causing
+	deadlock via different code paths; expand regression test
+
 2013-12-21  Peter Stephenson  <p.w.stephenson@ntlworld.com>
 
 	* Config/version.mk: update version to 5.0.4-dev-0 so as
diff --git a/Src/exec.c b/Src/exec.c
index 44800339f..f16cfd391 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -2389,7 +2389,7 @@ static void
 execcmd(Estate state, int input, int output, int how, int last1)
 {
     HashNode hn = NULL;
-    LinkList args;
+    LinkList args, filelist = NULL;
     LinkNode node;
     Redir fn;
     struct multio *mfds[10];
@@ -2911,6 +2911,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 	    flags |= ESUB_KEEPTRAP;
 	if (type == WC_SUBSH && !(how & Z_ASYNC))
 	    flags |= ESUB_JOB_CONTROL;
+	filelist = jobtab[thisjob].filelist;
 	entersubsh(flags);
 	close(synch[1]);
 	forked = 1;
@@ -3264,6 +3265,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 
 	    if (is_shfunc) {
 		/* It's a shell function */
+		pipecleanfilelist(filelist);
 		execshfunc((Shfunc) hn, args);
 	    } else {
 		/* It's a builtin */
@@ -3342,6 +3344,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		DPUTS(varspc,
 		      "BUG: assignment before complex command");
 		list_pipe = 0;
+		pipecleanfilelist(filelist);
 		/* If we're forked (and we should be), no need to return */
 		DPUTS(last1 != 1 && !forked, "BUG: not exiting?");
 		DPUTS(type != WC_SUBSH, "Not sure what we're doing.");
diff --git a/Src/jobs.c b/Src/jobs.c
index 371b8eb32..a32117217 100644
--- a/Src/jobs.c
+++ b/Src/jobs.c
@@ -1173,6 +1173,30 @@ addfilelist(const char *name, int fd)
     zaddlinknode(ll, jf);
 }
 
+/* Clean up pipes no longer needed associated with a job */
+
+/**/
+void
+pipecleanfilelist(LinkList filelist)
+{
+    LinkNode node;
+
+    if (!filelist)
+	return;
+    node = firstnode(filelist);
+    while (node) {
+	Jobfile jf = (Jobfile)getdata(node);
+	if (jf->is_fd) {
+	    LinkNode next = nextnode(node);
+	    zclose(jf->u.fd);
+	    (void)remnode(filelist, node);
+	    zfree(jf, sizeof(*jf));
+	    node = next;
+	} else
+	    incnode(node);
+    }
+}
+
 /* Finished with list of files for a job */
 
 /**/
@@ -1415,19 +1439,7 @@ zwaitjob(int job, int wait_cmd)
 	     * we can't deadlock on the fact that those still exist, so
 	     * that's not a problem.
 	     */
-	    LinkNode node = firstnode(jn->filelist);
-	    while (node) {
-		Jobfile jf = (Jobfile)getdata(node);
-		if (jf->is_fd) {
-		    LinkNode next = nextnode(node);
-		    (void)remnode(jn->filelist, node);
-		    zclose(jf->u.fd);
-		    zfree(jf, sizeof(*jf));
-		    node = next;
-		} else {
-		    incnode(node);
-		}
-	    }
+	    pipecleanfilelist(jn->filelist);
 	}
 	while (!errflag && jn->stat &&
 	       !(jn->stat & STAT_DONE) &&
diff --git a/Test/A05execution.ztst b/Test/A05execution.ztst
index 61d24fe1e..6abfd8b1f 100644
--- a/Test/A05execution.ztst
+++ b/Test/A05execution.ztst
@@ -207,10 +207,12 @@ F:This similar test was triggering a reproducible failure with pipestatus.
   coproc { read -Et 5 || kill -INT $$ }
   print -u $ZTST_fd 'This test takes 5 seconds to fail...'
   { printf "%d\n" {1..20000} } | ( read -E )
+  hang(){ printf "%d\n" {2..20000} | cat }; hang | ( read -E )
   print -p done
   read -Ep
 0:Bug regression: piping a shell construct to an external process may hang
 >1
+>2
 >done
 F:This test checks for a file descriptor leak that could cause the left
 F:side of a pipe to block on write after the right side has exited