kconfig: add xstrdup() helper

We already have xmalloc(), xcalloc(), and xrealloc(().  Add xstrdup()
as well to save tedious error handling.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/kconfig/confdata.c

@@ -178,7 +178,7 @@ static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 	case S_HEX:
 	done:
 		if (sym_string_valid(sym, p)) {
-			sym->def[def].val = strdup(p);
+			sym->def[def].val = xstrdup(p);
 			sym->flags |= def_flags;
 		} else {
 			if (def != S_DEF_AUTO)

scripts/kconfig/kxgettext.c

@@ -101,7 +101,7 @@ static struct message *message__new(const char *msg, char *option,
 	if (self->files == NULL)
 		goto out_fail;
 
-	self->msg = strdup(msg);
+	self->msg = xstrdup(msg);
 	if (self->msg == NULL)
 		goto out_fail_msg;
 

scripts/kconfig/lkc.h

@@ -115,6 +115,7 @@ int file_write_dep(const char *name);
 void *xmalloc(size_t size);
 void *xcalloc(size_t nmemb, size_t size);
 void *xrealloc(void *p, size_t size);
+char *xstrdup(const char *s);
 
 struct gstr {
 	size_t len;

scripts/kconfig/symbol.c

@@ -183,7 +183,7 @@ static void sym_validate_range(struct symbol *sym)
 		sprintf(str, "%lld", val2);
 	else
 		sprintf(str, "0x%llx", val2);
-	sym->curr.val = strdup(str);
+	sym->curr.val = xstrdup(str);
 }
 
 static void sym_set_changed(struct symbol *sym)
@@ -849,7 +849,7 @@ struct symbol *sym_lookup(const char *name, int flags)
 				   : !(symbol->flags & (SYMBOL_CONST|SYMBOL_CHOICE))))
 				return symbol;
 		}
-		new_name = strdup(name);
+		new_name = xstrdup(name);
 	} else {
 		new_name = NULL;
 		hash = 0;

scripts/kconfig/util.c

@@ -154,3 +154,14 @@ void *xrealloc(void *p, size_t size)
 	fprintf(stderr, "Out of memory.\n");
 	exit(1);
 }
+
+char *xstrdup(const char *s)
+{
+	char *p;
+
+	p = strdup(s);
+	if (p)
+		return p;
+	fprintf(stderr, "Out of memory.\n");
+	exit(1);
+}

scripts/kconfig/zconf.y

@@ -127,7 +127,7 @@ no_mainmenu_stmt: /* empty */
 	 * later regardless of whether it comes from the 'prompt' in
 	 * mainmenu_stmt or here
 	 */
-	menu_add_prompt(P_MENU, strdup("Linux Kernel Configuration"), NULL);
+	menu_add_prompt(P_MENU, xstrdup("Linux Kernel Configuration"), NULL);
 };