>From 758a8ee2b36f73766b1387974e0b3bf4bc87d1d8 Mon Sep 17 00:00:00 2001
From: Kamil Dudka <kdudka@redhat.com>
Date: Thu, 13 Apr 2017 14:08:49 +0200
Subject: [PATCH] doshfunc: reduce stack allocation in favour of heap

---
 Src/exec.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/Src/exec.c b/Src/exec.c
index f021a08..cde549e 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -5358,13 +5358,13 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
     char **pptab, **x, *oargv0;
     int oldzoptind, oldlastval, oldoptcind, oldnumpipestats, ret;
     int *oldpipestats = NULL;
-    char saveopts[OPT_SIZE], *oldscriptname = scriptname;
+    char *saveopts, *oldscriptname = scriptname;
     char *name = shfunc->node.nam;
     int flags = shfunc->node.flags, ooflags;
     char *fname = dupstring(name);
     int obreaks, ocontflag, oloops, saveemulation, restore_sticky;
     Eprog prog;
-    struct funcstack fstack;
+    struct funcstack *fstack;
     static int oflags;
     Emulation_options save_sticky = NULL;
 #ifdef MAX_FUNCTION_DEPTH
@@ -5409,6 +5409,7 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
 	/* We need to save the current options even if LOCALOPTIONS is *
 	 * not currently set.  That's because if it gets set in the    *
 	 * function we need to restore the original options on exit.   */
+	saveopts = (char *)zalloc(OPT_SIZE * sizeof(char));
 	memcpy(saveopts, opts, sizeof(opts));
 	saveemulation = emulation;
 	save_sticky = sticky;
@@ -5501,21 +5502,22 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
 		goto undoshfunc;
 	    }
 #endif
-	fstack.name = dupstring(name);
+	fstack = zalloc(sizeof(struct funcstack));
+	fstack->name = dupstring(name);
 	/*
 	 * The caller is whatever is immediately before on the stack,
 	 * unless we're at the top, in which case it's the script
 	 * or interactive shell name.
 	 */
-	fstack.caller = funcstack ? funcstack->name :
+	fstack->caller = funcstack ? funcstack->name :
 	    dupstring(oargv0 ? oargv0 : argzero);
-	fstack.lineno = lineno;
-	fstack.prev = funcstack;
-	fstack.tp = FS_FUNC;
-	funcstack = &fstack;
+	fstack->lineno = lineno;
+	fstack->prev = funcstack;
+	fstack->tp = FS_FUNC;
+	funcstack = fstack;
 
-	fstack.flineno = shfunc->lineno;
-	fstack.filename = getshfuncfile(shfunc);
+	fstack->flineno = shfunc->lineno;
+	fstack->filename = getshfuncfile(shfunc);
 
 	prog = shfunc->funcdef;
 	if (prog->flags & EF_RUN) {
@@ -5523,7 +5525,7 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
 
 	    prog->flags &= ~EF_RUN;
 
-	    runshfunc(prog, NULL, fstack.name);
+	    runshfunc(prog, NULL, fstack->name);
 
 	    if (!(shf = (Shfunc) shfunctab->getnode(shfunctab,
 						    (name = fname)))) {
@@ -5536,9 +5538,10 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
 	    }
 	    prog = shf->funcdef;
 	}
-	runshfunc(prog, wrappers, fstack.name);
+	runshfunc(prog, wrappers, fstack->name);
     doneshfunc:
-	funcstack = fstack.prev;
+	funcstack = fstack->prev;
+	zfree(fstack, sizeof(struct funcstack));
 #ifdef MAX_FUNCTION_DEPTH
     undoshfunc:
 	--funcdepth;
@@ -5586,6 +5589,8 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
 	    opts[WARNNESTEDVAR] = saveopts[WARNNESTEDVAR];
 	}
 
+	zfree(saveopts, OPT_SIZE * sizeof(char));
+
 	if (opts[LOCALLOOPS]) {
 	    if (contflag)
 		zwarn("`continue' active at end of function scope");
-- 
2.10.2