hush: set G.ifs sooner (prevents segfault)

function                                             old     new   delta
set_G_ifs                                              -     151    +151
run_list                                            1024    1031      +7
run_pipe                                            1567    1445    -122
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/1 up/down: 158/-122)           Total: 36 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

shell/hush.c

@@ -9250,6 +9250,37 @@ static int checkjobs_and_fg_shell(struct pipe *fg_pipe)
  * backgrounded: cmd &     { list } &
  * subshell:     ( list ) [&]
  */
+static void set_G_ifs(void)
+{
+	/* Testcase: set -- q w e; (IFS='' echo "$*"; IFS=''; echo "$*"); echo "$*"
+	 * Result should be 3 lines: q w e, qwe, q w e
+	 */
+	if (G.ifs_whitespace != G.ifs)
+		free(G.ifs_whitespace);
+	G.ifs = get_local_var_value("IFS");
+	if (G.ifs) {
+		char *p;
+		G.ifs_whitespace = (char*)G.ifs;
+		p = skip_whitespace(G.ifs);
+		if (*p) {
+			/* Not all $IFS is whitespace */
+			char *d;
+			int len = p - G.ifs;
+			p = skip_non_whitespace(p);
+			G.ifs_whitespace = xmalloc(len + strlen(p) + 1); /* can overestimate */
+			d = mempcpy(G.ifs_whitespace, G.ifs, len);
+			while (*p) {
+				if (isspace(*p))
+					*d++ = *p;
+				p++;
+			}
+			*d = '\0';
+		}
+	} else {
+		G.ifs = defifs;
+		G.ifs_whitespace = (char*)G.ifs;
+	}
+}
 #if !ENABLE_HUSH_MODE_X
 #define redirect_and_varexp_helper(command, sqp, argv_expanded) \
 	redirect_and_varexp_helper(command, sqp)
@@ -9286,34 +9317,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
 	debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
 	debug_enter();
 
-	/* Testcase: set -- q w e; (IFS='' echo "$*"; IFS=''; echo "$*"); echo "$*"
-	 * Result should be 3 lines: q w e, qwe, q w e
-	 */
-	if (G.ifs_whitespace != G.ifs)
-		free(G.ifs_whitespace);
-	G.ifs = get_local_var_value("IFS");
-	if (G.ifs) {
-		char *p;
-		G.ifs_whitespace = (char*)G.ifs;
-		p = skip_whitespace(G.ifs);
-		if (*p) {
-			/* Not all $IFS is whitespace */
-			char *d;
-			int len = p - G.ifs;
-			p = skip_non_whitespace(p);
-			G.ifs_whitespace = xmalloc(len + strlen(p) + 1); /* can overestimate */
-			d = mempcpy(G.ifs_whitespace, G.ifs, len);
-			while (*p) {
-				if (isspace(*p))
-					*d++ = *p;
-				p++;
-			}
-			*d = '\0';
-		}
-	} else {
-		G.ifs = defifs;
-		G.ifs_whitespace = (char*)G.ifs;
-	}
+	set_G_ifs();
 
 	IF_HUSH_JOB(pi->pgrp = -1;)
 	pi->stopped_cmds = 0;
@@ -9758,6 +9762,8 @@ static int run_list(struct pipe *pi)
 	debug_printf_exec("run_list lvl %d start\n", G.run_list_level);
 	debug_enter();
 
+	set_G_ifs();
+
 #if ENABLE_HUSH_LOOPS
 	/* Check syntax for "for" */
 	{