xshared: Introduce struct argv_store

The use of global variables in code around add_argv() is error-prone and
hard to follow. Replace them by a struct which functions will modify
instead of causing side-effects.

Given the lack of static variables, this effectively makes argv
construction code reentrant.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Florian Westphal <fw@strlen.de>

1 files changed, 15 insertions, 11 deletions

diff --git a/iptables/xshared.h b/iptables/xshared.h
index 21f4e8fd..64b7e8fc 100644
--- a/iptables/xshared.h
+++ b/iptables/xshared.h
@@ -156,18 +156,22 @@ bool xs_has_arg(int argc, char *argv[]);
 
 extern const struct xtables_afinfo *afinfo;
 
-extern char *newargv[];
-extern int newargc;
-
-extern char *oldargv[];
-extern int oldargc;
-
-extern int newargvattr[];
+#define MAX_ARGC	255
+struct argv_store {
+	int argc;
+	char *argv[MAX_ARGC];
+	int argvattr[MAX_ARGC];
+};
 
-int add_argv(const char *what, int quoted);
-void free_argv(void);
-void save_argv(void);
-void add_param_to_argv(char *parsestart, int line);
+void add_argv(struct argv_store *store, const char *what, int quoted);
+void free_argv(struct argv_store *store);
+void save_argv(struct argv_store *dst, struct argv_store *src);
+void add_param_to_argv(struct argv_store *store, char *parsestart, int line);
+#ifdef DEBUG
+void debug_print_argv(struct argv_store *store);
+#else
+#  define debug_print_argv(...) /* nothing */
+#endif
 
 void print_ipv4_addresses(const struct ipt_entry *fw, unsigned int format);
 void print_ipv6_addresses(const struct ip6t_entry *fw6, unsigned int format);