tests/server: round of tidy-ups (part 2)

General tidy-ups, to identify and reduce duplications and potential
issues, while also making the server modules compile as a single binary.

- ensure unique symbols and no shadowing across server sources, by
  renaming variables.
- move globals common to multiple servers into shared `util` module.
- drop constants with a single use.
- undef macro before re-using them across server sources.
- move common functions into shared `util` module.
- drop redundant static declarations.
- disable IPv6 code when built without IPv6.
- start syncing the 3 almost identical copies of `sockdaemon` function.
- drop unused `timeval.h` header.
- drop `poll()` from `wait_ms()`, for macOS, following an earlier core
  update.
  Follow-up to c72cefea0f #15096

Follow-up to 9213e4e497 #16525
Cherry-picked from #15000
Closes #16609

tests/server/sockfilt.c

@@ -114,20 +114,14 @@
 /* include memdebug.h last */
 #include "memdebug.h"
 
-#define DEFAULT_PORT 8999
-
 /* buffer is this excessively large only to be able to support things like
   test 1003 which tests exceedingly large server response lines */
 #define BUFFER_SIZE 17010
 
 static bool verbose = FALSE;
-static bool bind_only = FALSE;
-#ifdef USE_IPV6
-static bool use_ipv6 = FALSE;
-#endif
-static const char *ipv_inuse = "IPv4";
-static unsigned short port = DEFAULT_PORT;
-static unsigned short connectport = 0; /* if non-zero, we activate this mode */
+static bool s_bind_only = FALSE;
+static unsigned short server_connectport = 0; /* if non-zero,
+                                                 we activate this mode */
 
 enum sockmode {
   PASSIVE_LISTEN,    /* as a server waiting for connections */
@@ -1126,7 +1120,8 @@ static bool juggle(curl_socket_t *sockfdp,
     else if(!memcmp("PORT", buffer, 4)) {
       /* Question asking us what PORT number we are listening to.
          Replies to PORT with "IPv[num]/[port]" */
-      msnprintf((char *)buffer, sizeof(buffer), "%s/%hu\n", ipv_inuse, port);
+      msnprintf((char *)buffer, sizeof(buffer), "%s/%hu\n",
+                ipv_inuse, server_port);
       buffer_len = (ssize_t)strlen((char *)buffer);
       msnprintf(data, sizeof(data), "PORT\n%04zx\n", buffer_len);
       if(!write_stdout(data, 10))
@@ -1231,8 +1226,9 @@ static bool juggle(curl_socket_t *sockfdp,
 #endif
 }
 
-static curl_socket_t sockdaemon(curl_socket_t sock,
-                                unsigned short *listenport)
+static curl_socket_t sockfilt_sockdaemon(curl_socket_t sock,
+                                         unsigned short *listenport,
+                                         bool bind_only)
 {
   /* passive daemon style */
   srvr_sockaddr_union_t listener;
@@ -1380,8 +1376,6 @@ int main(int argc, char *argv[])
   curl_socket_t msgsock = CURL_SOCKET_BAD;
   int wrotepidfile = 0;
   int wroteportfile = 0;
-  const char *pidname = ".sockfilt.pid";
-  const char *portname = NULL; /* none by default */
   bool juggle_again;
   int rc;
   int error;
@@ -1389,7 +1383,9 @@ int main(int argc, char *argv[])
   enum sockmode mode = PASSIVE_LISTEN; /* default */
   const char *addr = NULL;
 
+  pidname = ".sockfilt.pid";
   serverlogfile = "log/sockfilt.log";
+  server_port = 8999;
 
   while(argc > arg) {
     if(!strcmp("--version", argv[arg])) {
@@ -1437,7 +1433,7 @@ int main(int argc, char *argv[])
       arg++;
     }
     else if(!strcmp("--bindonly", argv[arg])) {
-      bind_only = TRUE;
+      s_bind_only = TRUE;
       arg++;
     }
     else if(!strcmp("--port", argv[arg])) {
@@ -1445,7 +1441,7 @@ int main(int argc, char *argv[])
       if(argc > arg) {
         char *endptr;
         unsigned long ulnum = strtoul(argv[arg], &endptr, 10);
-        port = util_ultous(ulnum);
+        server_port = util_ultous(ulnum);
         arg++;
       }
     }
@@ -1462,7 +1458,7 @@ int main(int argc, char *argv[])
                   argv[arg]);
           return 0;
         }
-        connectport = util_ultous(ulnum);
+        server_connectport = util_ultous(ulnum);
         arg++;
       }
     }
@@ -1518,7 +1514,7 @@ int main(int argc, char *argv[])
     goto sockfilt_cleanup;
   }
 
-  if(connectport) {
+  if(server_connectport) {
     /* Active mode, we should connect to the given port number */
     mode = ACTIVE;
 #ifdef USE_IPV6
@@ -1526,7 +1522,7 @@ int main(int argc, char *argv[])
 #endif
       memset(&me.sa4, 0, sizeof(me.sa4));
       me.sa4.sin_family = AF_INET;
-      me.sa4.sin_port = htons(connectport);
+      me.sa4.sin_port = htons(server_connectport);
       me.sa4.sin_addr.s_addr = INADDR_ANY;
       if(!addr)
         addr = "127.0.0.1";
@@ -1538,7 +1534,7 @@ int main(int argc, char *argv[])
     else {
       memset(&me.sa6, 0, sizeof(me.sa6));
       me.sa6.sin6_family = AF_INET6;
-      me.sa6.sin6_port = htons(connectport);
+      me.sa6.sin6_port = htons(server_connectport);
       if(!addr)
         addr = "::1";
       Curl_inet_pton(AF_INET6, addr, &me.sa6.sin6_addr);
@@ -1549,7 +1545,7 @@ int main(int argc, char *argv[])
     if(rc) {
       error = SOCKERRNO;
       logmsg("Error connecting to port %hu (%d) %s",
-             connectport, error, sstrerror(error));
+             server_connectport, error, sstrerror(error));
       write_stdout("FAIL\n", 5);
       goto sockfilt_cleanup;
     }
@@ -1558,7 +1554,7 @@ int main(int argc, char *argv[])
   }
   else {
     /* passive daemon style */
-    sock = sockdaemon(sock, &port);
+    sock = sockfilt_sockdaemon(sock, &server_port, s_bind_only);
     if(CURL_SOCKET_BAD == sock) {
       write_stdout("FAIL\n", 5);
       goto sockfilt_cleanup;
@@ -1568,12 +1564,12 @@ int main(int argc, char *argv[])
 
   logmsg("Running %s version", ipv_inuse);
 
-  if(connectport)
-    logmsg("Connected to port %hu", connectport);
-  else if(bind_only)
-    logmsg("Bound without listening on port %hu", port);
+  if(server_connectport)
+    logmsg("Connected to port %hu", server_connectport);
+  else if(s_bind_only)
+    logmsg("Bound without listening on port %hu", server_port);
   else
-    logmsg("Listening on port %hu", port);
+    logmsg("Listening on port %hu", server_port);
 
   wrotepidfile = write_pidfile(pidname);
   if(!wrotepidfile) {
@@ -1581,7 +1577,7 @@ int main(int argc, char *argv[])
     goto sockfilt_cleanup;
   }
   if(portname) {
-    wroteportfile = write_portfile(portname, port);
+    wroteportfile = write_portfile(portname, server_port);
     if(!wroteportfile) {
       write_stdout("FAIL\n", 5);
       goto sockfilt_cleanup;