slirp: Allocate/free stack instance dynamically

Allocate the internal slirp state dynamically and provide and call
slirp_cleanup to properly release it after use. This patch finally
unbreaks slirp release and re-instantiation via host_net_* monitor
commands.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

4 files changed, 21 insertions, 15 deletions

diff --git a/libslirp.h b/libslirp.h
index 955d55c..b8d83fa 100644
--- a/libslirp.h
+++ b/libslirp.h
@@ -13,6 +13,7 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
                   const char *vhostname, const char *tftp_path,
                   const char *bootfile, struct in_addr vdhcp_start,
                   struct in_addr vnameserver, void *opaque);
+void slirp_cleanup(Slirp *slirp);
 
 void slirp_select_fill(int *pnfds, fd_set *readfds, fd_set *writefds,
                        fd_set *xfds);
diff --git a/main.h b/main.h
index 2d30bab..686683b 100644
--- a/main.h
+++ b/main.h
@@ -11,7 +11,6 @@
 
 #define TOWRITEMAX 512
 
-extern int link_up;
 extern int slirp_socket;
 extern int slirp_socket_unit;
 extern int slirp_socket_port;
diff --git a/slirp.c b/slirp.c
index ed7e0a3..c0d8eec 100644
--- a/slirp.c
+++ b/slirp.c
@@ -40,8 +40,6 @@ static const uint8_t special_ethaddr[6] = {
 
 static const uint8_t zero_ethaddr[6] = { 0, 0, 0, 0, 0, 0 };
 
-int link_up; // FIXME: kill this
-
 /* XXX: suppress those select globals */
 fd_set *global_readfds, *global_writefds, *global_xfds;
 
@@ -49,7 +47,7 @@ u_int curtime;
 static u_int time_fasttimo, last_slowtimo;
 static int do_slowtimo;
 
-Slirp slirp_instance;
+Slirp *slirp_instance;
 
 #ifdef _WIN32
 
@@ -193,11 +191,10 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
                   const char *bootfile, struct in_addr vdhcp_start,
                   struct in_addr vnameserver, void *opaque)
 {
-    Slirp *slirp = &slirp_instance;
+    Slirp *slirp = qemu_mallocz(sizeof(Slirp));
 
     slirp_init_once();
 
-    link_up = 1;
     slirp->restricted = restricted;
 
     if_init(slirp);
@@ -213,13 +210,9 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
         pstrcpy(slirp->client_hostname, sizeof(slirp->client_hostname),
                 vhostname);
     }
-    qemu_free(slirp->tftp_prefix);
-    slirp->tftp_prefix = NULL;
     if (tftp_path) {
         slirp->tftp_prefix = qemu_strdup(tftp_path);
     }
-    qemu_free(slirp->bootp_filename);
-    slirp->bootp_filename = NULL;
     if (bootfile) {
         slirp->bootp_filename = qemu_strdup(bootfile);
     }
@@ -230,9 +223,22 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
 
     register_savevm("slirp", 0, 2, slirp_state_save, slirp_state_load, slirp);
 
+    slirp_instance = slirp;
+
     return slirp;
 }
 
+void slirp_cleanup(Slirp *slirp)
+{
+    unregister_savevm("slirp", slirp);
+
+    qemu_free(slirp->tftp_prefix);
+    qemu_free(slirp->bootp_filename);
+    qemu_free(slirp);
+
+    slirp_instance = NULL;
+}
+
 #define CONN_CANFSEND(so) \
     (((so)->so_state & (SS_FCANTSENDMORE | SS_ISFCONNECTED)) == SS_ISFCONNECTED)
 #define CONN_CANFRCV(so) \
@@ -267,11 +273,11 @@ static void updtime(void)
 void slirp_select_fill(int *pnfds, fd_set *readfds, fd_set *writefds,
                        fd_set *xfds)
 {
-    Slirp *slirp = &slirp_instance;
+    Slirp *slirp = slirp_instance;
     struct socket *so, *so_next;
     int nfds;
 
-    if (!link_up) {
+    if (!slirp_instance) {
         return;
     }
 
@@ -387,11 +393,11 @@ void slirp_select_fill(int *pnfds, fd_set *readfds, fd_set *writefds,
 void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds,
                        int select_error)
 {
-    Slirp *slirp = &slirp_instance;
+    Slirp *slirp = slirp_instance;
     struct socket *so, *so_next;
     int ret;
 
-    if (!link_up) {
+    if (!slirp_instance) {
         return;
     }
 
diff --git a/slirp.h b/slirp.h
index 5cb13aa..0d6fc4e 100644
--- a/slirp.h
+++ b/slirp.h
@@ -259,7 +259,7 @@ struct Slirp {
     void *opaque;
 };
 
-extern Slirp slirp_instance;
+extern Slirp *slirp_instance;
 
 #ifndef NULL
 #define NULL (void *)0