From 6a193c032d11766b32466dac4ce61f9fe589a808 Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Tue, 13 Aug 2019 20:04:09 -0700
Subject: [PATCH] ETHER: Fix possible race conditions when closing a network
 device

Added pcap version to the SCP output of SHOW VERSION command.
---
 scp.c                  |  3 +++
 sim_ether.c            | 28 +++++++++++++++++-----------
 sim_ether.h            |  1 +
 slirp_glue/sim_slirp.c |  2 ++
 4 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/scp.c b/scp.c
index 39b440a4..750a7a7d 100644
--- a/scp.c
+++ b/scp.c
@@ -5866,6 +5866,9 @@ if (flag) {
 #endif
     fprintf (st, "\n        OS clock resolution: %dms", os_tick_size);
     fprintf (st, "\n        Time taken by msleep(1): %dms", os_ms_sleep_1);
+    if (eth_version ())
+        fprintf (st, "\n        Ethernet packet info: %s", eth_version());
+    fprintf (st, "\n        Time taken by msleep(1): %dms", os_ms_sleep_1);
 #if defined(__VMS)
     if (1) {
         char *arch = 
diff --git a/sim_ether.c b/sim_ether.c
index b1675f0e..916769c1 100644
--- a/sim_ether.c
+++ b/sim_ether.c
@@ -750,7 +750,6 @@ static char*   (*p_pcap_lib_version) (void);
 
 static ETH_DEV **eth_open_devices = NULL;
 static int eth_open_device_count = 0;
-static t_bool eth_show_active = FALSE;
 
 #if defined (USE_NETWORK) || defined (USE_SHARED)
 static void _eth_add_to_open_list (ETH_DEV* dev)
@@ -778,7 +777,6 @@ t_stat eth_show (FILE* st, UNIT* uptr, int32 val, CONST void* desc)
   ETH_LIST  list[ETH_MAX_DEVICE];
   int number;
 
-  eth_show_active = TRUE;
   number = eth_devices(ETH_MAX_DEVICE, list);
   fprintf(st, "ETH devices:\n");
   if (number == -1)
@@ -794,9 +792,6 @@ t_stat eth_show (FILE* st, UNIT* uptr, int32 val, CONST void* desc)
       for (i=0; i<number; i++)
         fprintf(st," eth%d\t%-*s (%s)\n", i, (int)min, list[i].name, list[i].desc);
     }
-  if (p_pcap_lib_version) {
-    fprintf(st, "%s\n", p_pcap_lib_version());
-    }
   if (eth_open_device_count) {
     int i;
     char desc[ETH_DEV_DESC_MAX], *d;
@@ -811,7 +806,6 @@ t_stat eth_show (FILE* st, UNIT* uptr, int32 val, CONST void* desc)
       eth_show_dev (st, eth_open_devices[i]);
       }
     }
-  eth_show_active = FALSE;
   return SCPE_OK;
 }
 
@@ -964,6 +958,8 @@ t_stat eth_filter_hash (ETH_DEV* dev, int addr_count, ETH_MAC* const addresses,
   {return SCPE_NOFNC;}
 int eth_devices (int max, ETH_LIST* dev)
   {return -1;}
+const char *eth_version (void)
+  {return NULL;}
 void eth_show_dev (FILE* st, ETH_DEV* dev)
   {}
 static int _eth_get_system_id (char *buf, size_t buf_size)
@@ -1188,11 +1184,6 @@ int load_pcap(void) {
       load_function("pcap_setfilter",    (_func *) &p_pcap_setfilter);
       load_function("pcap_setnonblock",  (_func *) &p_pcap_setnonblock);
       load_function("pcap_lib_version",  (_func *) &p_pcap_lib_version);
-
-      if ((lib_loaded == 1) && (!eth_show_active)) {
-        /* log successful load */
-        sim_messagef (SCPE_OK, "%s\n", p_pcap_lib_version());
-      }
       break;
     default:                /* loaded or failed */
       break;
@@ -1220,6 +1211,14 @@ int pcap_compile(pcap_t* a, struct bpf_program* b, const char* c, int d, bpf_u_i
   }
 }
 
+const char *pcap_lib_version(void) {
+  if ((load_pcap() != 0) && (p_pcap_lib_version != NULL)) {
+    return p_pcap_lib_version();
+  } else {
+    return NULL;
+  }
+}
+
 int pcap_datalink(pcap_t* a) {
   if (a && (load_pcap() != 0)) {
     return p_pcap_datalink(a);
@@ -1903,6 +1902,8 @@ sim_debug(dev->dbit, dev->dptr, "Writer Thread Starting\n");
 pthread_mutex_lock (&dev->writer_lock);
 while (dev->handle) {
   pthread_cond_wait (&dev->writer_cond, &dev->writer_lock);
+  if (dev->handle == NULL)      /* Shutting down? */
+      break;
   while (NULL != (request = dev->write_requests)) {
     /* Pull buffer off request list */
     dev->write_requests = request->next;
@@ -2437,6 +2438,11 @@ _eth_remove_from_open_list (dev);
 return SCPE_OK;
 }
 
+const char *eth_version (void)
+{
+return pcap_lib_version();
+}
+
 t_stat eth_attach_help(FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
 {
 fprintf (st, "%s attach help\n\n", dptr->name);
diff --git a/sim_ether.h b/sim_ether.h
index 2c95ff89..02c84cec 100644
--- a/sim_ether.h
+++ b/sim_ether.h
@@ -349,6 +349,7 @@ t_stat eth_filter_hash (ETH_DEV* dev, int addr_count,   /* set filter on incomin
                         ETH_MULTIHASH* const hash);
 t_stat eth_check_address_conflict (ETH_DEV* dev, 
                                    ETH_MAC* const address);
+const char *eth_version (void);                         /* Version of dynamically loaded library (pcap) */
 int eth_devices   (int max, ETH_LIST* dev);             /* get ethernet devices on host */
 void eth_setcrc   (ETH_DEV* dev, int need_crc);         /* enable/disable CRC mode */
 t_stat eth_set_async (ETH_DEV* dev, int latency);       /* set read behavior to be async */
diff --git a/slirp_glue/sim_slirp.c b/slirp_glue/sim_slirp.c
index 912899d4..f44d1b95 100644
--- a/slirp_glue/sim_slirp.c
+++ b/slirp_glue/sim_slirp.c
@@ -595,6 +595,8 @@ fd_set rfds, wfds, xfds;
 fd_set save_rfds, save_wfds, save_xfds;
 int nfds;
 
+if (!slirp)                         /* Not active? */
+    return -1;                      /* That's an error */
 /* Populate the GPollFDs from slirp */
 g_array_set_size (slirp->gpollfds, 1);  /* Leave the doorbell chime alone */
 slirp_pollfds_fill(slirp->gpollfds, &slirp_timeout);