New scriptarg=... -net parameter allows passing of an argument to the script.

Previously, network scripts would have to do all of their work based
only on the script name and interface name.  If the script's behaviour
is supposed to be different for different network interfaces this
might involve constructing a special script for each interface with
the associated need to delete it etc.

With this patch it is possible to specify
  -net=...,scriptarg=<extra-info>
which gets passed as a $2 to the qemu-ifup script.

diff --git a/vl.c b/vl.c
index 229b536bbbecdc5b848b8e5fdfe7376407219ca9..28f6fe0e1fb1a4140de3e7f9f2a984e282cea1ba 100644 (file)
--- a/vl.c
+++ b/vl.c
@@ -3963,6 +3963,7 @@ typedef struct TAPState {
     VLANClientState *vc;
     int fd;
     char down_script[1024];
+    char script_arg[1024];
 } TAPState;
 
 static void tap_receive(void *opaque, const uint8_t *buf, int size)
@@ -4198,10 +4199,11 @@ static int tap_open(char *ifname, int ifname_size)
 }
 #endif
 
-static int launch_script(const char *setup_script, const char *ifname, int fd)
+static int launch_script(const char *setup_script, const char *ifname,
+                        const char *script_arg, int fd)
 {
     int pid, status;
-    char *args[3];
+    char *args[4];
     char **parg;
 
         /* try to launch network script */
@@ -4219,6 +4221,8 @@ static int launch_script(const char *setup_script, const char *ifname, int fd)
                 parg = args;
                 *parg++ = (char *)setup_script;
                 *parg++ = (char *)ifname;
+                if (script_arg && script_arg[0])
+                    *parg++ = (char *)script_arg;
                 *parg++ = NULL;
                 execv(setup_script, args);
                 _exit(1);
@@ -4235,7 +4239,8 @@ static int launch_script(const char *setup_script, const char *ifname, int fd)
 }
 
 static int net_tap_init(VLANState *vlan, const char *ifname1,
-                        const char *setup_script, const char *down_script)
+                        const char *setup_script, const char *down_script,
+                        const char *script_arg)
 {
     TAPState *s;
     int fd;
@@ -4252,7 +4257,7 @@ static int net_tap_init(VLANState *vlan, const char *ifname1,
     if (!setup_script || !strcmp(setup_script, "no"))
         setup_script = "";
     if (setup_script[0] != '\0') {
-       if (launch_script(setup_script, ifname, fd))
+       if (launch_script(setup_script, ifname, script_arg, fd))
            return -1;
     }
     s = net_tap_fd_init(vlan, fd);
@@ -4262,6 +4267,8 @@ static int net_tap_init(VLANState *vlan, const char *ifname1,
              "tap: ifname=%s setup_script=%s", ifname, setup_script);
     if (down_script && strcmp(down_script, "no"))
         snprintf(s->down_script, sizeof(s->down_script), "%s", down_script);
+    if (script_arg && script_arg[0])
+        snprintf(s->script_arg, sizeof(s->script_arg), "%s", script_arg);
     return 0;
 }
 
@@ -4854,7 +4861,7 @@ static int net_client_init(const char *str)
 #else
     if (!strcmp(device, "tap")) {
         char ifname[64];
-        char setup_script[1024], down_script[1024];
+        char setup_script[1024], down_script[1024], script_arg[1024];
         int fd;
         vlan->nb_host_devs++;
         if (get_param_value(buf, sizeof(buf), "fd", p) > 0) {
@@ -4873,7 +4880,10 @@ static int net_client_init(const char *str)
             if (get_param_value(down_script, sizeof(down_script), "downscript", p) == 0) {
                 pstrcpy(down_script, sizeof(down_script), DEFAULT_NETWORK_DOWN_SCRIPT);
             }
-            ret = net_tap_init(vlan, ifname, setup_script, down_script);
+            if (get_param_value(script_arg, sizeof(script_arg), "scriptarg", p) == 0) {
+                pstrcpy(script_arg, sizeof(script_arg), "");
+            }
+            ret = net_tap_init(vlan, ifname, setup_script, down_script, script_arg);
         }
     } else
 #endif
@@ -7191,11 +7201,12 @@ static void help(int exitcode)
            "-net tap[,vlan=n],ifname=name\n"
            "                connect the host TAP network interface to VLAN 'n'\n"
 #else
-           "-net tap[,vlan=n][,fd=h][,ifname=name][,script=file][,downscript=dfile]\n"
+           "-net tap[,vlan=n][,fd=h][,ifname=name][,script=file][,downscript=dfile][,scriptarg=extraargument]\n"
            "                connect the host TAP network interface to VLAN 'n' and use the\n"
            "                network scripts 'file' (default=%s)\n"
            "                and 'dfile' (default=%s);\n"
            "                use '[down]script=no' to disable script execution;\n"
+           "                use 'scriptarg=...' to pass an additional (nonempty) argument;\n"
            "                use 'fd=h' to connect to an already opened TAP interface\n"
 #endif
            "-net socket[,vlan=n][,fd=h][,listen=[host]:port][,connect=host:port]\n"
@@ -8638,7 +8649,7 @@ int main(int argc, char **argv)
 
                 if (sscanf(vc->info_str, "tap: ifname=%63s ", ifname) == 1 &&
                     s->down_script[0])
-                    launch_script(s->down_script, ifname, s->fd);
+                    launch_script(s->down_script, ifname, s->script_arg, s->fd);
             }
         }
     }