Complete conversion of s6-ipcserver and s6-tcpserver (4 and 6)

to socketbinder + d model. With documentation (!)

5 files changed, 277 insertions, 790 deletions

diff --git a/src/conn-tools/s6-ipcserver.c b/src/conn-tools/s6-ipcserver.c
index 890fc3d..b6546f8 100644
--- a/src/conn-tools/s6-ipcserver.c
+++ b/src/conn-tools/s6-ipcserver.c
@@ -101,8 +101,8 @@ int main (int argc, char const *const *argv, char const *const *envp)
       newargv[m++] = "--" ;
     }
     newargv[m++] = S6_NETWORKING_BINPREFIX "s6-ipcserverd" ;
-    if (!verbosity) newargv[m++] = "-q" ;
-    else if (verbosity == 2) newargv[m++] = "-v" ;
+    if (!verbosity) newargv[m++] = "-v0" ;
+    else if (verbosity == 2) newargv[m++] = "-v2" ;
     if (flag1) newargv[m++] = "-1" ;
     if (!flaglookup) newargv[m++] = "-P" ;
     if (maxconn)
diff --git a/src/conn-tools/s6-ipcserverd.c b/src/conn-tools/s6-ipcserverd.c
index 419b123..4afe5cc 100644
--- a/src/conn-tools/s6-ipcserverd.c
+++ b/src/conn-tools/s6-ipcserverd.c
@@ -20,7 +20,7 @@
 #include <skalibs/iopause.h>
 #include <skalibs/webipc.h>
 
-#define USAGE "s6-ipcserverd [ -q | -Q | -v ] [ -1 ] [ -P | -p ] [ -c maxconn ] [ -C localmaxconn ] prog..."
+#define USAGE "s6-ipcserverd [ -v verbosity ] [ -1 ] [ -P | -p ] [ -c maxconn ] [ -C localmaxconn ] prog..."
 
 #define ABSOLUTE_MAXCONN 1000
 
@@ -303,18 +303,16 @@ int main (int argc, char const *const *argv, char const *const *envp)
     int flag1 = 0 ;
     for (;;)
     {
-      register int opt = subgetopt_r(argc, argv, "qQv1Ppc:C:", &l) ;
+      register int opt = subgetopt_r(argc, argv, "Pp1c:C:v:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
-        case 'q' : verbosity = 0 ; break ;
-        case 'Q' : verbosity = 1 ; break ;
-        case 'v' : verbosity = 2 ; break ;
-        case '1' : flag1 = 1 ; break ;
         case 'P' : flaglookup = 0 ; break ;
         case 'p' : flaglookup = 1 ; break ;
+        case '1' : flag1 = 1 ; break ;
         case 'c' : if (!uint0_scan(l.arg, &maxconn)) dieusage() ; break ;
         case 'C' : if (!uint0_scan(l.arg, &localmaxconn)) dieusage() ; break ;
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
         default : dieusage() ;
       }
     }
diff --git a/src/conn-tools/s6-tcpserver.c b/src/conn-tools/s6-tcpserver.c
index fcbf4f2..751b2b8 100644
--- a/src/conn-tools/s6-tcpserver.c
+++ b/src/conn-tools/s6-tcpserver.c
@@ -1,71 +1,136 @@
 /* ISC license. */
 
+#include <sys/types.h>
+#include <limits.h>
 #include <skalibs/uint.h>
+#include <skalibs/gidstuff.h>
 #include <skalibs/sgetopt.h>
 #include <skalibs/strerr2.h>
 #include <skalibs/djbunix.h>
 #include <skalibs/ip46.h>
+#include <s6/config.h>
 #include <s6-networking/config.h>
 
-#define USAGE "s6-tcpserver [ -q | -Q | -v ] [ -1 ] [ -4 | -6 ] [ -c maxconn ] [ -C localmaxconn ] [ -b backlog ] [ -G gid,gid,... ] [ -g gid ] [ -u uid ] [ -U ] ip port prog..."
+#define USAGE "s6-tcpserver [ -q | -Q | -v ] [ -4 | -6 ] [ -d | -D ] [ -1 ] [ -c maxconn ] [ -C localmaxconn ] [ -b backlog ] [ -G gid,gid,... ] [ -g gid ] [ -u uid ] [ -U ] ip port prog..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const *const *argv, char const *const *envp)
 {
-  char const *newargv[2 + (argc << 1)] ;
-  char const *path ;
-  unsigned int m = 3 ;
-  int what = 0 ;
   unsigned int verbosity = 1 ;
-  char fmtv[UINT_FMT] ;
+  int flag1 = 0 ;
+  int flagU = 0 ;
+  int flagreuse = 1 ;
+  unsigned int uid = 0, gid = 0 ;
+  gid_t gids[NGROUPS_MAX] ;
+  unsigned int gidn = (unsigned int)-1 ;
+  unsigned int maxconn = 0 ;
+  unsigned int localmaxconn = 0 ;
+  unsigned int backlog = (unsigned int)-1 ;
+  unsigned int what = 0 ;
   PROG = "s6-tcpserver" ;
-  newargv[1] = "-v" ;
-  newargv[2] = fmtv ;
   {
     subgetopt_t l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      register int opt = subgetopt_r(argc, argv, "qQv146Uc:C:b:u:g:G:", &l) ;
+      register int opt = subgetopt_r(argc, argv, "qQvDd1U46c:C:b:u:g:G:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
-        case '4' : if (what) dieusage() ; what = 4 ; break ;
-        case '6' : if (what) dieusage() ; what = 6 ; break ;
         case 'q' : verbosity = 0 ; break ;
         case 'Q' : verbosity = 1 ; break ;
         case 'v' : verbosity = 2 ; break ;
-        case '1' : newargv[m++] = "-1" ; break ;
-        case 'U' : newargv[m++] = "-U" ; break ;
-        case 'c' : newargv[m++] = "-c" ; newargv[m++] = l.arg ; break ;
-        case 'C' : newargv[m++] = "-C" ; newargv[m++] = l.arg ; break ;
-        case 'b' : newargv[m++] = "-b" ; newargv[m++] = l.arg ; break ;
-        case 'u' : newargv[m++] = "-u" ; newargv[m++] = l.arg ; break ;
-        case 'g' : newargv[m++] = "-g" ; newargv[m++] = l.arg ; break ;
-        case 'G' : newargv[m++] = "-G" ; newargv[m++] = l.arg ; break ;
+        case 'D' : flagreuse = 0 ; break ;
+        case 'd' : flagreuse = 1 ; break ;
+        case '4' : what = 4 ; break ;
+        case '6' : what = 6 ; break ;
+        case 'c' : if (!uint0_scan(l.arg, &maxconn)) dieusage() ; if (!maxconn) maxconn = 1 ; break ;
+        case 'C' : if (!uint0_scan(l.arg, &localmaxconn)) dieusage() ; if (!localmaxconn) localmaxconn = 1 ; break ;
+        case 'b' : if (!uint0_scan(l.arg, &backlog)) dieusage() ; break ;
+        case 'u' : if (!uint0_scan(l.arg, &uid)) dieusage() ; break ;
+        case 'g' : if (!uint0_scan(l.arg, &gid)) dieusage() ; break ;
+        case 'G' : if (!gid_scanlist(gids, NGROUPS_MAX, l.arg, &gidn) && *l.arg) dieusage() ; break ;
+        case '1' : flag1 = 1 ; break ;
+        case 'U' : flagU = 1 ; uid = 0 ; gid = 0 ; gidn = (unsigned int)-1 ; break ;
         default : dieusage() ;
       }
     }
     argc -= l.ind ; argv += l.ind ;
+    if (argc < 3) dieusage() ;
   }
-  if (argc < 3) dieusage() ;
-  fmtv[uint_fmt(fmtv, verbosity)] = 0 ;
-  newargv[m++] = 0 ;
+
   if (!what)
   {
     ip46_t ip ;
     if (!ip46_scan(argv[0], &ip)) dieusage() ;
     what = ip46_is6(&ip) ? 6 : 4 ;
   }
-  if (what == 6)
-  {
-    newargv[0] = "s6-tcpserver6" ;
-    path = S6_NETWORKING_BINPREFIX "s6-tcpserver6" ;
-  }
-  else
+
   {
-    newargv[0] = "s6-tcpserver4" ;
-    path = S6_NETWORKING_BINPREFIX "s6-tcpserver4" ;
+    unsigned int m = 0 ;
+    unsigned int pos = 0 ;
+    char fmt[UINT_FMT * 5 + GID_FMT * NGROUPS_MAX] ;
+    char const *newargv[23 + argc] ;
+    newargv[m++] = what == 6 ? S6_NETWORKING_BINPREFIX "s6-tcpserver6-socketbinder" : S6_NETWORKING_BINPREFIX "s6-tcpserver4-socketbinder" ;
+    if (!flagreuse) newargv[m++] = "-D" ;
+    if (backlog != (unsigned int)-1)
+    {
+      newargv[m++] = "-b" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, backlog) ;
+      fmt[pos++] = 0 ;
+    }
+    newargv[m++] = "--" ;
+    newargv[m++] = *argv++ ;
+    newargv[m++] = *argv++ ;
+    if (flagU || uid || gid || gidn != (unsigned int)-1)
+    {
+      newargv[m++] = S6_EXTBINPREFIX "s6-applyuidgid" ;
+      if (flagU) newargv[m++] = "-Uz" ;
+      if (uid)
+      {
+        newargv[m++] = "-u" ;
+        newargv[m++] = fmt + pos ;
+        pos += uint_fmt(fmt + pos, uid) ;
+        fmt[pos++] = 0 ;
+      }
+      if (gid)
+      {
+        newargv[m++] = "-g" ;
+        newargv[m++] = fmt + pos ;
+        pos += uint_fmt(fmt + pos, gid) ;
+        fmt[pos++] = 0 ;
+      }
+      if (gidn != (unsigned int)-1)
+      {
+        newargv[m++] = "-G" ;
+        newargv[m++] = fmt + pos ;
+        pos += gid_fmtlist(fmt + pos, gids, gidn) ;
+        fmt[pos++] = 0 ;
+      }
+      newargv[m++] = "--" ;
+    }
+    newargv[m++] = what == 6 ? S6_NETWORKING_BINPREFIX "s6-tcpserver6d" : S6_NETWORKING_BINPREFIX "s6-tcpserver4d" ;
+    if (!verbosity) newargv[m++] = "-v0" ;
+    else if (verbosity == 2) newargv[m++] = "-v2" ;
+    if (flag1) newargv[m++] = "-1" ;
+    if (maxconn)
+    {
+      newargv[m++] = "-c" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, maxconn) ;
+      fmt[pos++] = 0 ;
+    }
+    if (localmaxconn)
+    {
+      newargv[m++] = "-C" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, localmaxconn) ;
+      fmt[pos++] = 0 ;
+    }
+    newargv[m++] = "--" ;
+    while (*argv) newargv[m++] = *argv++ ;
+    newargv[m++] = 0 ;
+    pathexec_run(newargv[0], newargv, envp) ;
+    strerr_dieexec(111, newargv[0]) ;
   }
-  pathexec_run(path, newargv, envp) ;
-  strerr_dieexec(111, path) ;
 }
diff --git a/src/conn-tools/s6-tcpserver4.c b/src/conn-tools/s6-tcpserver4.c
index e030b6d..6a85110 100644
--- a/src/conn-tools/s6-tcpserver4.c
+++ b/src/conn-tools/s6-tcpserver4.c
@@ -1,417 +1,128 @@
 /* ISC license. */
 
-#include <skalibs/nonposix.h>
 #include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/wait.h>
-#include <errno.h>
-#include <unistd.h>
-#include <fcntl.h>
 #include <limits.h>
-#include <grp.h>
-#include <signal.h>
-#include <skalibs/gccattributes.h>
-#include <skalibs/allreadwrite.h>
-#include <skalibs/uint16.h>
-#include <skalibs/uint32.h>
 #include <skalibs/uint.h>
 #include <skalibs/gidstuff.h>
-#include <skalibs/setgroups.h>
-#include <skalibs/bytestr.h>
 #include <skalibs/sgetopt.h>
-#include <skalibs/fmtscan.h>
 #include <skalibs/strerr2.h>
-#include <skalibs/diuint32.h>
-#include <skalibs/env.h>
 #include <skalibs/djbunix.h>
-#include <skalibs/sig.h>
-#include <skalibs/selfpipe.h>
-#include <skalibs/iopause.h>
-#include <skalibs/socket.h>
+#include <s6/config.h>
+#include <s6-networking/config.h>
 
-#define ABSOLUTE_MAXCONN 1000
-
-#define USAGE "s6-tcpserver4 [ -v verbosity ] [ -1 ] [ -c maxconn ] [ -C localmaxconn ] [ -b backlog ] [ -G gid,gid,... ] [ -g gid ] [ -u uid ] [ -U ] ip port prog..."
-
-static unsigned int maxconn = 40 ;
-static unsigned int localmaxconn = 40 ;
-static unsigned int verbosity = 1 ;
-static int cont = 1 ;
-static diuint32 *pidip = 0 ;
-static unsigned int numconn = 0 ;
-static diuint32 *ipnum = 0 ;
-static unsigned int iplen = 0 ;
-
-static char fmtmaxconn[UINT_FMT+1] = "/" ;
-static char fmtlocalmaxconn[UINT_FMT+1] = "/" ;
-
-
- /* Utility functions */
-
-static inline void dieusage ()
-{
-  strerr_dieusage(100, USAGE) ;
-}
-
-static inline void X (void)
-{
-  strerr_dief1x(101, "internal inconsistency. Please submit a bug-report.") ;
-}
-
-
- /* Lookup primitives */
- 
-static unsigned int lookup_diuint32 (diuint32 const *, unsigned int, unsigned int) gccattr_pure ;
-static unsigned int lookup_diuint32 (diuint32 const *tab, unsigned int tablen, unsigned int key)
-{
-  register unsigned int i = 0 ;
-  for (; i < tablen ; i++) if (key == tab[i].left) break ;
-  return i ;
-}
-
-static inline unsigned int lookup_pid (uint32 pid)
-{
-  return lookup_diuint32(pidip, numconn, pid) ;
-}
-
-static inline unsigned int lookup_ip (uint32 ip)
-{
-  return lookup_diuint32(ipnum, iplen, ip) ;
-}
-
-
- /* Logging */
-
-static void log_start (char const *ip, uint16 port)
-{
-  char fmtip[IP4_FMT] ;
-  char fmtport[UINT16_FMT] ;
-  fmtip[ip4_fmt(fmtip, ip)] = 0 ;
-  fmtport[uint16_fmt(fmtport, port)] = 0 ;
-  strerr_warni4x("starting - listening on ", fmtip, ":", fmtport) ;
-}
-
-static inline void log_exit (void)
-{
-  strerr_warni1x("exiting") ;
-}
-
-static void log_status (void)
-{
-  char fmt[UINT_FMT] ;
-  fmt[uint_fmt(fmt, numconn)] = 0 ;
-  strerr_warni3x("status: ", fmt, fmtmaxconn) ;
-}
-
-static void log_deny (uint32 ip, uint16 port, unsigned int num)
-{
-  char fmtip[UINT32_FMT] ;
-  char fmtport[UINT16_FMT] ;
-  char fmtnum[UINT_FMT] ;
-  fmtip[ip4_fmtu32(fmtip, ip)] = 0 ;
-  fmtport[uint16_fmt(fmtport, port)] = 0 ;
-  fmtnum[uint_fmt(fmtnum, num)] = 0 ;
-  strerr_warni7sys("deny ", fmtip, ":", fmtport, " count ", fmtnum, fmtlocalmaxconn) ;
-}
-
-static void log_accept (uint32 pid, uint32 ip, uint16 port, unsigned int num)
-{
-  char fmtipport[IP4_FMT + UINT16_FMT + 1] ;
-  char fmtpid[UINT32_FMT] ;
-  char fmtnum[UINT_FMT] ;
-  register unsigned int n ;
-  n = ip4_fmtu32(fmtipport, ip) ;
-  fmtipport[n++] = ':' ;
-  n += uint16_fmt(fmtipport + n, port) ;
-  fmtipport[n] = 0 ;
-  fmtnum[uint_fmt(fmtnum, num)] = 0 ;
-  fmtpid[uint32_fmt(fmtpid, pid)] = 0 ;
-  strerr_warni7x("allow ", fmtipport, " pid ", fmtpid, " count ", fmtnum, fmtlocalmaxconn) ;
-}
-
-static void log_close (uint32 pid, uint32 ip, int w)
-{
-  char fmtpid[UINT32_FMT] ;
-  char fmtip[IP4_FMT] = "?" ;
-  char fmtw[UINT_FMT] ;
-  fmtpid[uint32_fmt(fmtpid, pid)] = 0 ;
-  fmtip[ip4_fmtu32(fmtip, ip)] = 0 ;
-  fmtw[uint_fmt(fmtw, WIFSIGNALED(w) ? WTERMSIG(w) : WEXITSTATUS(w))] = 0 ;
-  strerr_warni6x("end pid ", fmtpid, " ip ", fmtip, WIFSIGNALED(w) ? " signal " : " exitcode ", fmtw) ;
-}
-
-
- /* Signal handling */
-
-static void killthem (int sig)
-{
-  register unsigned int i = 0 ;
-  for (; i < numconn ; i++) kill(pidip[i].left, sig) ;
-}
-
-static void wait_children (void)
-{
-  for (;;)
-  {
-    unsigned int i ;
-    int w ;
-    register int pid = wait_nohang(&w) ;
-    if (pid < 0)
-      if (errno != ECHILD) strerr_diefu1sys(111, "wait_nohang") ;
-      else break ;
-    else if (!pid) break ;
-    i = lookup_pid(pid) ;
-    if (i < numconn) /* it's one of ours ! */
-    {
-      uint32 ip = pidip[i].right ;
-      register unsigned int j = lookup_ip(ip) ;
-      if (j >= iplen) X() ;
-      if (!--ipnum[j].right) ipnum[j] = ipnum[--iplen] ;
-      pidip[i] = pidip[--numconn] ;
-      if (verbosity >= 2)
-      {
-        log_close(pid, ip, w) ;
-        log_status() ;
-      }
-    }
-  }
-}
-
-static void handle_signals (void)
-{
-  for (;;) switch (selfpipe_read())
-  {
-    case -1 : strerr_diefu1sys(111, "read selfpipe") ;
-    case 0 : return ;
-    case SIGCHLD : wait_children() ; break ;
-    case SIGTERM :
-    {
-      if (verbosity >= 2)
-        strerr_warni3x("received ", "SIGTERM,", " quitting") ;
-      cont = 0 ;
-      break ;
-    }
-    case SIGHUP :
-    {
-      if (verbosity >= 2)
-        strerr_warni5x("received ", "SIGHUP,", " sending ", "SIGTERM+SIGCONT", " to all connections") ;
-      killthem(SIGTERM) ;
-      killthem(SIGCONT) ;
-      break ;
-    }
-    case SIGQUIT :
-    {
-      if (verbosity >= 2)
-        strerr_warni6x("received ", "SIGQUIT,", " sending ", "SIGTERM+SIGCONT", " to all connections", " and quitting") ;
-      cont = 0 ;
-      killthem(SIGTERM) ;
-      killthem(SIGCONT) ;
-      break ;
-    }
-    case SIGABRT :
-    {
-      if (verbosity >= 2)
-        strerr_warni6x("received ", "SIGABRT,", " sending ", "SIGKILL", " to all connections", " and quitting") ;
-      cont = 0 ;
-      killthem(SIGKILL) ;
-      break ;
-    }
-    default : X() ;
-  }
-}
-
-
- /* New connection handling */
-
-static void run_child (int, uint32, uint16, unsigned int, char const *const *, char const *const *) gccattr_noreturn ;
-static void run_child (int s, uint32 ip, uint16 port, unsigned int num, char const *const *argv, char const *const *envp)
-{
-  char fmt[74] ;
-  unsigned int n = 0 ;
-  PROG = "s6-tcpserver (child)" ;
-  if ((fd_move(0, s) < 0) || (fd_copy(1, 0) < 0))
-    strerr_diefu1sys(111, "move fds") ;
-  byte_copy(fmt+n, 22, "PROTO=TCP\0TCPREMOTEIP=") ; n += 22 ;
-  n += ip4_fmtu32(fmt+n, ip) ; fmt[n++] = 0 ;
-  byte_copy(fmt+n, 14, "TCPREMOTEPORT=") ; n += 14 ;
-  n += uint16_fmt(fmt+n, port) ; fmt[n++] = 0 ;
-  byte_copy(fmt+n, 11, "TCPCONNNUM=") ; n += 11 ;
-  n += uint_fmt(fmt+n, num) ; fmt[n++] = 0 ;
-  pathexec_r(argv, envp, env_len(envp), fmt, n) ;
-  strerr_dieexec(111, argv[0]) ;
-}
-
-static void new_connection (int s, uint32 ip, uint16 port, char const *const *argv, char const *const *envp)
-{
-  unsigned int i = lookup_ip(ip) ;
-  unsigned int num = (i < iplen) ? ipnum[i].right : 0 ;
-  register int pid ;
-  if (num >= localmaxconn)
-  {
-    log_deny(ip, port, num) ;
-    return ;
-  }
-  pid = fork() ;
-  if (pid < 0)
-  {
-    if (verbosity) strerr_warnwu1sys("fork") ;
-    return ;
-  }
-  else if (!pid)
-  {
-    selfpipe_finish() ;
-    run_child(s, ip, port, num+1, argv, envp) ;
-  }
-
-  if (i < iplen) ipnum[i].right = num + 1 ;
-  else
-  {
-    ipnum[iplen].left = ip ;
-    ipnum[iplen++].right = 1 ;
-  }
-  pidip[numconn].left = (uint32)pid ;
-  pidip[numconn++].right = ip ;
-  if (verbosity >= 2)
-  {
-    log_accept((uint32)pid, ip, port, ipnum[i].right) ;
-    log_status() ;
-  }
-}
-
-
- /* And the main */
+#define USAGE "s6-tcpserver4 [ -v verbosity ] [ -d | -D ] [ -1 ] [ -c maxconn ] [ -C localmaxconn ] [ -b backlog ] [ -G gid,gid,... ] [ -g gid ] [ -u uid ] [ -U ] ip port prog..."
+#define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const *const *argv, char const *const *envp)
 {
-  iopause_fd x[2] = { { -1, IOPAUSE_READ, 0 }, { -1, IOPAUSE_READ | IOPAUSE_EXCEPT, 0 } } ;
+  unsigned int verbosity = 1 ;
+  int flag1 = 0 ;
+  int flagU = 0 ;
+  int flagreuse = 1 ;
+  unsigned int uid = 0, gid = 0 ;
+  gid_t gids[NGROUPS_MAX] ;
+  unsigned int gidn = (unsigned int)-1 ;
+  unsigned int maxconn = 0 ;
+  unsigned int localmaxconn = 0 ;
+  unsigned int backlog = (unsigned int)-1 ;
   PROG = "s6-tcpserver4" ;
   {
     subgetopt_t l = SUBGETOPT_ZERO ;
-    unsigned int uid = 0, gid = 0 ;
-    gid_t gids[NGROUPS_MAX] ;
-    unsigned int gidn = 0 ;
-    unsigned int backlog = 20 ;
-    char ip[4] ;
-    int flag1 = 0 ;
-    uint16 port ;
     for (;;)
     {
-      register int opt = subgetopt_r(argc, argv, "1Uc:C:b:u:g:G:v:", &l) ;
+      register int opt = subgetopt_r(argc, argv, "Dd1Uv:c:C:b:u:g:G:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
-        case '1' : flag1 = 1 ; break ;
-        case 'c' : if (!uint0_scan(l.arg, &maxconn)) dieusage() ; break ;
-        case 'C' : if (!uint0_scan(l.arg, &localmaxconn)) dieusage() ; break ;
+        case 'D' : flagreuse = 0 ; break ;
+        case 'd' : flagreuse = 1 ; break ;
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+        case 'c' : if (!uint0_scan(l.arg, &maxconn)) dieusage() ; if (!maxconn) maxconn = 1 ; break ;
+        case 'C' : if (!uint0_scan(l.arg, &localmaxconn)) dieusage() ; if (!localmaxconn) localmaxconn = 1 ; break ;
         case 'b' : if (!uint0_scan(l.arg, &backlog)) dieusage() ; break ;
         case 'u' : if (!uint0_scan(l.arg, &uid)) dieusage() ; break ;
         case 'g' : if (!uint0_scan(l.arg, &gid)) dieusage() ; break ;
-        case 'G' : if (!gid_scanlist(gids, NGROUPS_MAX, l.arg, &gidn)) dieusage() ; break ;
-        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
-        case 'U' :
-        {
-          char const *x = env_get2(envp, "UID") ;
-          if (!x) strerr_dienotset(100, "UID") ;
-          if (!uint0_scan(x, &uid)) strerr_dieinvalid(100, "UID") ;
-          x = env_get2(envp, "GID") ;
-          if (!x) strerr_dienotset(100, "GID") ;
-          if (!uint0_scan(x, &gid)) strerr_dieinvalid(100, "GID") ;
-          x = env_get2(envp, "GIDLIST") ;
-          if (!x) strerr_dienotset(100, "GIDLIST") ;
-          if (!gid_scanlist(gids, NGROUPS_MAX, x, &gidn) && *x)
-            strerr_dieinvalid(100, "GIDLIST") ;
-          break ;
-        }
+        case 'G' : if (!gid_scanlist(gids, NGROUPS_MAX, l.arg, &gidn) && *l.arg) dieusage() ; break ;
+        case '1' : flag1 = 1 ; break ;
+        case 'U' : flagU = 1 ; uid = 0 ; gid = 0 ; gidn = (unsigned int)-1 ; break ;
         default : dieusage() ;
       }
     }
     argc -= l.ind ; argv += l.ind ;
     if (argc < 3) dieusage() ;
-    if (!ip4_scan(argv[0], ip) || !uint160_scan(argv[1], &port)) dieusage() ;
-    close(0) ;
-    if (flag1)
+  }
+
+  {
+    unsigned int m = 0 ;
+    unsigned int pos = 0 ;
+    char fmt[UINT_FMT * 6 + GID_FMT * NGROUPS_MAX] ;
+    char const *newargv[24 + argc] ;
+    newargv[m++] = S6_NETWORKING_BINPREFIX "s6-tcpserver4-socketbinder" ;
+    if (!flagreuse) newargv[m++] = "-D" ;
+    if (backlog != (unsigned int)-1)
     {
-      if (fcntl(1, F_GETFD) < 0)
-        strerr_dief1sys(100, "called with option -1 but stdout said") ;
+      newargv[m++] = "-b" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, backlog) ;
+      fmt[pos++] = 0 ;
     }
-    else close(1) ;
-    if (!maxconn) maxconn = 1 ;
-    if (maxconn > ABSOLUTE_MAXCONN) maxconn = ABSOLUTE_MAXCONN ;
-    if (localmaxconn > maxconn) localmaxconn = maxconn ;
-    x[1].fd = socket_tcp4() ;
-    if ((x[1].fd == -1) || (coe(x[1].fd) == -1))
-      strerr_diefu1sys(111, "create socket") ;
-    if (socket_bind4_reuse(x[1].fd, ip, port) < 0)
-      strerr_diefu2sys(111, "bind to ", argv[0]) ;
-    if (socket_listen(x[1].fd, backlog) == -1)
-      strerr_diefu1sys(111, "listen") ;
-    if (gidn && (setgroups(gidn, gids) < 0)) strerr_diefu1sys(111, "setgroups") ;
-    if (gid && (setgid(gid) < 0)) strerr_diefu1sys(111, "drop gid") ;
-    if (uid && (setuid(uid) < 0)) strerr_diefu1sys(111, "drop uid") ;
-
-    x[0].fd = selfpipe_init() ;
-    if (x[0].fd == -1) strerr_diefu1sys(111, "create selfpipe") ;
-    if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
+    newargv[m++] = "--" ;
+    newargv[m++] = *argv++ ;
+    newargv[m++] = *argv++ ;
+    if (flagU || uid || gid || gidn != (unsigned int)-1)
     {
-      sigset_t set ;
-      sigemptyset(&set) ;
-      sigaddset(&set, SIGCHLD) ;
-      sigaddset(&set, SIGTERM) ;
-      sigaddset(&set, SIGHUP) ;
-      sigaddset(&set, SIGQUIT) ;
-      sigaddset(&set, SIGABRT) ;
-      if (selfpipe_trapset(&set) < 0) strerr_diefu1sys(111, "trap signals") ;
+      newargv[m++] = S6_EXTBINPREFIX "s6-applyuidgid" ;
+      if (flagU) newargv[m++] = "-Uz" ;
+      if (uid)
+      {
+        newargv[m++] = "-u" ;
+        newargv[m++] = fmt + pos ;
+        pos += uint_fmt(fmt + pos, uid) ;
+        fmt[pos++] = 0 ;
+      }
+      if (gid)
+      {
+        newargv[m++] = "-g" ;
+        newargv[m++] = fmt + pos ;
+        pos += uint_fmt(fmt + pos, gid) ;
+        fmt[pos++] = 0 ;
+      }
+      if (gidn != (unsigned int)-1)
+      {
+        newargv[m++] = "-G" ;
+        newargv[m++] = fmt + pos ;
+        pos += gid_fmtlist(fmt + pos, gids, gidn) ;
+        fmt[pos++] = 0 ;
+      }
+      newargv[m++] = "--" ;
     }
-    if (flag1)
+    newargv[m++] = S6_NETWORKING_BINPREFIX "s6-tcpserver4d" ;
+    if (verbosity != 1)
     {
-      char fmt[UINT16_FMT] ;
-      unsigned int n = uint16_fmt(fmt, port) ;
-      fmt[n++] = '\n' ;
-      allwrite(1, fmt, n) ;
-      fd_close(1) ;
+      newargv[m++] = "-v" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, verbosity) ;
+      fmt[pos++] = 0 ;
     }
-    fmtlocalmaxconn[1+uint_fmt(fmtlocalmaxconn+1, localmaxconn)] = 0 ;
-    if (verbosity >= 2)
+    if (flag1) newargv[m++] = "-1" ;
+    if (maxconn)
     {
-      fmtmaxconn[1+uint_fmt(fmtmaxconn+1, maxconn)] = 0 ;
-      log_start(ip, port) ;
-      log_status() ;
+      newargv[m++] = "-c" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, maxconn) ;
+      fmt[pos++] = 0 ;
     }
-  }
-
-  {
-    diuint32 inyostack[maxconn<<1] ;
-    pidip = inyostack ; ipnum = inyostack + maxconn ;
-    while (cont)
+    if (localmaxconn)
     {
-      if (iopause_g(x, 1 + (numconn < maxconn), 0) < 0)
-        strerr_diefu1sys(111, "iopause") ;
-
-      if (x[0].revents & IOPAUSE_EXCEPT) strerr_dief1x(111, "trouble with selfpipe") ;
-      if (x[0].revents & IOPAUSE_READ) handle_signals() ;
-      if (numconn < maxconn)
-      {
-        if (x[1].revents & IOPAUSE_EXCEPT) strerr_dief1x(111, "trouble with socket") ;
-        if (x[1].revents & IOPAUSE_READ)
-        {
-          char packedip[4] ;
-          uint16 port ;
-          register int fd = socket_accept4(x[1].fd, packedip, &port) ;
-          if (fd < 0)
-          {
-            if (verbosity) strerr_warnwu1sys("accept") ;
-          }
-          else
-          {
-            uint32 ip ;
-            uint32_unpack_big(packedip, &ip) ;
-            new_connection(fd, ip, port, argv+2, envp) ;
-            fd_close(fd) ;
-          }
-        }
-      }
+      newargv[m++] = "-C" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, localmaxconn) ;
+      fmt[pos++] = 0 ;
     }
+    newargv[m++] = "--" ;
+    while (*argv) newargv[m++] = *argv++ ;
+    newargv[m++] = 0 ;
+    pathexec_run(newargv[0], newargv, envp) ;
+    strerr_dieexec(111, newargv[0]) ;
   }
-  if (verbosity >= 2) log_exit() ;
-  return 0 ;
 }
diff --git a/src/conn-tools/s6-tcpserver6.c b/src/conn-tools/s6-tcpserver6.c
index 999a564..7cffb54 100644
--- a/src/conn-tools/s6-tcpserver6.c
+++ b/src/conn-tools/s6-tcpserver6.c
@@ -1,415 +1,128 @@
 /* ISC license. */
 
-#include <skalibs/nonposix.h>
 #include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/wait.h>
-#include <errno.h>
-#include <unistd.h>
-#include <fcntl.h>
 #include <limits.h>
-#include <grp.h>
-#include <signal.h>
-#include <skalibs/gccattributes.h>
-#include <skalibs/allreadwrite.h>
-#include <skalibs/uint16.h>
 #include <skalibs/uint.h>
 #include <skalibs/gidstuff.h>
-#include <skalibs/setgroups.h>
-#include <skalibs/bytestr.h>
 #include <skalibs/sgetopt.h>
-#include <skalibs/fmtscan.h>
 #include <skalibs/strerr2.h>
-#include <skalibs/env.h>
 #include <skalibs/djbunix.h>
-#include <skalibs/sig.h>
-#include <skalibs/selfpipe.h>
-#include <skalibs/iopause.h>
-#include <skalibs/socket.h>
-
-#define ABSOLUTE_MAXCONN 1000
-
-#define USAGE "s6-tcpserver6 [ -v verbosity ] [ -1 ] [ -c maxconn ] [ -C localmaxconn ] [ -b backlog ] [ -G gid,gid,... ] [ -g gid ] [ -u uid ] [ -U ] ip6 port prog..."
-
-typedef struct ipnum_s ipnum_t, *ipnum_t_ref ;
-struct ipnum_s
-{
-  char ip[16] ;
-  unsigned int num ;
-} ;
-#define IPNUM_ZERO { "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 0 }
-
-static unsigned int maxconn = 40 ;
-static unsigned int localmaxconn = 40 ;
-static unsigned int verbosity = 1 ;
-static int cont = 1 ;
-static ipnum_t_ref pidip = 0 ;
-static unsigned int numconn = 0 ;
-static ipnum_t_ref ipnum = 0 ;
-static unsigned int iplen = 0 ;
-
-static char fmtmaxconn[UINT_FMT+1] = "/" ;
-static char fmtlocalmaxconn[UINT_FMT+1] = "/" ;
-
-
- /* Utility functions */
-
-static inline void dieusage ()
-{
-  strerr_dieusage(100, USAGE) ;
-}
-
-static inline void X (void)
-{
-  strerr_dief1x(101, "internal inconsistency. Please submit a bug-report.") ;
-}
-
-
- /* Lookup primitives */
- 
-static unsigned int lookup_pid (unsigned int pid)
-{
-  register unsigned int i = 0 ;
-  for (; i < numconn ; i++) if (pid == pidip[i].num) break ;
-  return i ;
-}
-
-static unsigned int lookup_ip (char const *ip)
-{
-  register unsigned int i = 0 ;
-  for (; i < iplen ; i++) if (!byte_diff(ip, 16, ipnum[i].ip)) break ;
-  return i ;
-}
-
-
- /* Logging */
-
-static void log_start (char const *ip, uint16 port)
-{
-  char fmtip[IP6_FMT] ;
-  char fmtport[UINT16_FMT] ;
-  fmtip[ip6_fmt(fmtip, ip)] = 0 ;
-  fmtport[uint16_fmt(fmtport, port)] = 0 ;
-  strerr_warni4x("starting - listening on ", fmtip, " port ", fmtport) ;
-}
-
-static inline void log_exit (void)
-{
-  strerr_warni1x("exiting") ;
-}
-
-static void log_status (void)
-{
-  char fmt[UINT_FMT] ;
-  fmt[uint_fmt(fmt, numconn)] = 0 ;
-  strerr_warni3x("status: ", fmt, fmtmaxconn) ;
-}
-
-static void log_deny (char const *ip, uint16 port, unsigned int num)
-{
-  char fmtip[IP6_FMT] ;
-  char fmtport[UINT16_FMT] ;
-  char fmtnum[UINT_FMT] ;
-  fmtip[ip6_fmt(fmtip, ip)] = 0 ;
-  fmtport[uint16_fmt(fmtport, port)] = 0 ;
-  fmtnum[uint_fmt(fmtnum, num)] = 0 ;
-  strerr_warni7sys("deny ", fmtip, " port ", fmtport, " count ", fmtnum, fmtlocalmaxconn) ;
-}
-
-static void log_accept (unsigned int pid, char const *ip, uint16 port, unsigned int num)
-{
-  char fmtipport[IP6_FMT + UINT16_FMT + 6] ;
-  char fmtpid[UINT_FMT] ;
-  char fmtnum[UINT_FMT] ;
-  register unsigned int n ;
-  n = ip6_fmt(fmtipport, ip) ;
-  byte_copy(fmtipport + n, 6, " port ") ; n += 6 ;
-  n += uint16_fmt(fmtipport + n, port) ;
-  fmtipport[n] = 0 ;
-  fmtnum[uint_fmt(fmtnum, num)] = 0 ;
-  fmtpid[uint_fmt(fmtpid, pid)] = 0 ;
-  strerr_warni7x("allow ", fmtipport, " pid ", fmtpid, " count ", fmtnum, fmtlocalmaxconn) ;
-}
-
-static void log_close (unsigned int pid, char const *ip, int w)
-{
-  char fmtpid[UINT_FMT] ;
-  char fmtip[IP6_FMT] = "?" ;
-  char fmtw[UINT_FMT] ;
-  fmtpid[uint_fmt(fmtpid, pid)] = 0 ;
-  fmtip[ip6_fmt(fmtip, ip)] = 0 ;
-  fmtw[uint_fmt(fmtw, WIFSIGNALED(w) ? WTERMSIG(w) : WEXITSTATUS(w))] = 0 ;
-  strerr_warni6x("end pid ", fmtpid, " ip ", fmtip, WIFSIGNALED(w) ? " signal " : " exitcode ", fmtw) ;
-}
-
-
- /* Signal handling */
-
-static void killthem (int sig)
-{
-  register unsigned int i = 0 ;
-  for (; i < numconn ; i++) kill(pidip[i].num, sig) ;
-}
-
-static void wait_children (void)
-{
-  for (;;)
-  {
-    unsigned int i ;
-    int w ;
-    register int pid = wait_nohang(&w) ;
-    if (pid < 0)
-      if (errno != ECHILD) strerr_diefu1sys(111, "wait_nohang") ;
-      else break ;
-    else if (!pid) break ;
-    i = lookup_pid(pid) ;
-    if (i < numconn) /* it's one of ours ! */
-    {
-      register unsigned int j = lookup_ip(pidip[i].ip) ;
-      if (j >= iplen) X() ;
-      if (!--ipnum[j].num) ipnum[j] = ipnum[--iplen] ;
-      --numconn ;
-      if (verbosity >= 2)
-      {
-        log_close(pid, pidip[i].ip, w) ;
-        log_status() ;
-      }
-      pidip[i] = pidip[numconn] ;
-    }
-  }
-}
-
-static void handle_signals (void)
-{
-  for (;;) switch (selfpipe_read())
-  {
-    case -1 : strerr_diefu1sys(111, "read selfpipe") ;
-    case 0 : return ;
-    case SIGCHLD : wait_children() ; break ;
-    case SIGTERM :
-    {
-      if (verbosity >= 2)
-        strerr_warni3x("received ", "SIGTERM,", " quitting") ;
-      cont = 0 ;
-      break ;
-    }
-    case SIGHUP :
-    {
-      if (verbosity >= 2)
-        strerr_warni5x("received ", "SIGHUP,", " sending ", "SIGTERM+SIGCONT", " to all connections") ;
-      killthem(SIGTERM) ;
-      killthem(SIGCONT) ;
-      break ;
-    }
-    case SIGQUIT :
-    {
-      if (verbosity >= 2)
-        strerr_warni6x("received ", "SIGQUIT,", " sending ", "SIGTERM+SIGCONT", " to all connections", " and quitting") ;
-      cont = 0 ;
-      killthem(SIGTERM) ;
-      killthem(SIGCONT) ;
-      break ;
-    }
-    case SIGABRT :
-    {
-      if (verbosity >= 2)
-        strerr_warni6x("received ", "SIGABRT,", " sending ", "SIGKILL", " to all connections", " and quitting") ;
-      cont = 0 ;
-      killthem(SIGKILL) ;
-      break ;
-    }
-    default : X() ;
-  }
-}
-
-
- /* New connection handling */
-
-static void run_child (int, char const *, uint16, unsigned int, char const *const *, char const *const *) gccattr_noreturn ;
-static void run_child (int s, char const *ip, uint16 port, unsigned int num, char const *const *argv, char const *const *envp)
-{
-  char fmt[98] ;
-  unsigned int n = 0 ;
-  PROG = "s6-tcpserver6 (child)" ;
-  if ((fd_move(0, s) < 0) || (fd_copy(1, 0) < 0))
-    strerr_diefu1sys(111, "move fds") ;
-  byte_copy(fmt+n, 24, "PROTO=TCP\0TCPREMOTEIP=") ; n += 22 ;
-  n += ip6_fmt(fmt+n, ip) ; fmt[n++] = 0 ;
-  byte_copy(fmt+n, 14, "TCPREMOTEPORT=") ; n += 14 ;
-  n += uint16_fmt(fmt+n, port) ; fmt[n++] = 0 ;
-  byte_copy(fmt+n, 11, "TCPCONNNUM=") ; n += 11 ;
-  n += uint_fmt(fmt+n, num) ; fmt[n++] = 0 ;
-  pathexec_r(argv, envp, env_len(envp), fmt, n) ;
-  strerr_dieexec(111, argv[0]) ;
-}
-
-static void new_connection (int s, char const *ip, uint16 port, char const *const *argv, char const *const *envp)
-{
-  unsigned int i = lookup_ip(ip) ;
-  unsigned int num = (i < iplen) ? ipnum[i].num : 0 ;
-  register int pid ;
-  if (num >= localmaxconn)
-  {
-    log_deny(ip, port, num) ;
-    return ;
-  }
-  pid = fork() ;
-  if (pid < 0)
-  {
-    if (verbosity) strerr_warnwu1sys("fork") ;
-    return ;
-  }
-  else if (!pid)
-  {
-    selfpipe_finish() ;
-    run_child(s, ip, port, num+1, argv, envp) ;
-  }
-
-  if (i < iplen) ipnum[i].num = num + 1 ;
-  else
-  {
-    byte_copy(ipnum[iplen].ip, 16, ip) ;
-    ipnum[iplen++].num = 1 ;
-  }
-  pidip[numconn].num = pid ;
-  byte_copy(pidip[numconn++].ip, 16, ip) ;
-  if (verbosity >= 2)
-  {
-    log_accept(pid, ip, port, ipnum[i].num) ;
-    log_status() ;
-  }
-}
+#include <s6/config.h>
+#include <s6-networking/config.h>
 
+#define USAGE "s6-tcpserver6 [ -v verbosity ] [ -d | -D ] [ -1 ] [ -c maxconn ] [ -C localmaxconn ] [ -b backlog ] [ -G gid,gid,... ] [ -g gid ] [ -u uid ] [ -U ] ip port prog..."
+#define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const *const *argv, char const *const *envp)
 {
-  iopause_fd x[2] = { { -1, IOPAUSE_READ, 0 }, { -1, IOPAUSE_READ | IOPAUSE_EXCEPT, 0 } } ;
+  unsigned int verbosity = 1 ;
+  int flag1 = 0 ;
+  int flagU = 0 ;
+  int flagreuse = 1 ;
+  unsigned int uid = 0, gid = 0 ;
+  gid_t gids[NGROUPS_MAX] ;
+  unsigned int gidn = (unsigned int)-1 ;
+  unsigned int maxconn = 0 ;
+  unsigned int localmaxconn = 0 ;
+  unsigned int backlog = (unsigned int)-1 ;
   PROG = "s6-tcpserver6" ;
   {
     subgetopt_t l = SUBGETOPT_ZERO ;
-    unsigned int uid = 0, gid = 0 ;
-    gid_t gids[NGROUPS_MAX] ;
-    unsigned int gidn = 0 ;
-    unsigned int backlog = 20 ;
-    char ip[16] ;
-    int flag1 = 0 ;
-    uint16 port ;
     for (;;)
     {
-      register int opt = subgetopt_r(argc, argv, "1Uc:C:b:u:g:G:v:", &l) ;
+      register int opt = subgetopt_r(argc, argv, "Dd1Uv:c:C:b:u:g:G:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
-        case '1' : flag1 = 1 ; break ;
-        case 'c' : if (!uint0_scan(l.arg, &maxconn)) dieusage() ; break ;
-        case 'C' : if (!uint0_scan(l.arg, &localmaxconn)) dieusage() ; break ;
+        case 'D' : flagreuse = 0 ; break ;
+        case 'd' : flagreuse = 1 ; break ;
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+        case 'c' : if (!uint0_scan(l.arg, &maxconn)) dieusage() ; if (!maxconn) maxconn = 1 ; break ;
+        case 'C' : if (!uint0_scan(l.arg, &localmaxconn)) dieusage() ; if (!localmaxconn) localmaxconn = 1 ; break ;
         case 'b' : if (!uint0_scan(l.arg, &backlog)) dieusage() ; break ;
         case 'u' : if (!uint0_scan(l.arg, &uid)) dieusage() ; break ;
         case 'g' : if (!uint0_scan(l.arg, &gid)) dieusage() ; break ;
-        case 'G' : if (!gid_scanlist(gids, NGROUPS_MAX, l.arg, &gidn)) dieusage() ; break ;
-        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
-        case 'U' :
-        {
-          char const *x = env_get2(envp, "UID") ;
-          if (!x) strerr_dienotset(100, "UID") ;
-          if (!uint0_scan(x, &uid)) strerr_dieinvalid(100, "UID") ;
-          x = env_get2(envp, "GID") ;
-          if (!x) strerr_dienotset(100, "GID") ;
-          if (!uint0_scan(x, &gid)) strerr_dieinvalid(100, "GID") ;
-          x = env_get2(envp, "GIDLIST") ;
-          if (!x) strerr_dienotset(100, "GIDLIST") ;
-          if (!gid_scanlist(gids, NGROUPS_MAX, x, &gidn) && *x)
-            strerr_dieinvalid(100, "GIDLIST") ;
-          break ;
-        }
+        case 'G' : if (!gid_scanlist(gids, NGROUPS_MAX, l.arg, &gidn) && *l.arg) dieusage() ; break ;
+        case '1' : flag1 = 1 ; break ;
+        case 'U' : flagU = 1 ; uid = 0 ; gid = 0 ; gidn = (unsigned int)-1 ; break ;
         default : dieusage() ;
       }
     }
     argc -= l.ind ; argv += l.ind ;
     if (argc < 3) dieusage() ;
-    if (!ip6_scan(argv[0], ip) || !uint160_scan(argv[1], &port)) dieusage() ;
-    close(0) ;
-    if (flag1)
+  }
+
+  {
+    unsigned int m = 0 ;
+    unsigned int pos = 0 ;
+    char fmt[UINT_FMT * 6 + GID_FMT * NGROUPS_MAX] ;
+    char const *newargv[24 + argc] ;
+    newargv[m++] = S6_NETWORKING_BINPREFIX "s6-tcpserver6-socketbinder" ;
+    if (!flagreuse) newargv[m++] = "-D" ;
+    if (backlog != (unsigned int)-1)
     {
-      if (fcntl(1, F_GETFD) < 0)
-        strerr_dief1sys(100, "called with option -1 but stdout said") ;
+      newargv[m++] = "-b" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, backlog) ;
+      fmt[pos++] = 0 ;
     }
-    else close(1) ;
-    if (!maxconn) maxconn = 1 ;
-    if (maxconn > ABSOLUTE_MAXCONN) maxconn = ABSOLUTE_MAXCONN ;
-    if (localmaxconn > maxconn) localmaxconn = maxconn ;
-    x[1].fd = socket_tcp6() ;
-    if ((x[1].fd == -1) || (coe(x[1].fd) == -1))
-      strerr_diefu1sys(111, "create socket") ;
-    if (socket_bind6_reuse(x[1].fd, ip, port) < 0)
-      strerr_diefu2sys(111, "bind to ", argv[0]) ;
-    if (socket_listen(x[1].fd, backlog) == -1)
-      strerr_diefu1sys(111, "listen") ;
-    if (gidn && (setgroups(gidn, gids) < 0)) strerr_diefu1sys(111, "setgroups") ;
-    if (gid && (setgid(gid) < 0)) strerr_diefu1sys(111, "drop gid") ;
-    if (uid && (setuid(uid) < 0)) strerr_diefu1sys(111, "drop uid") ;
-
-    x[0].fd = selfpipe_init() ;
-    if (x[0].fd == -1) strerr_diefu1sys(111, "create selfpipe") ;
-    if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
+    newargv[m++] = "--" ;
+    newargv[m++] = *argv++ ;
+    newargv[m++] = *argv++ ;
+    if (flagU || uid || gid || gidn != (unsigned int)-1)
     {
-      sigset_t set ;
-      sigemptyset(&set) ;
-      sigaddset(&set, SIGCHLD) ;
-      sigaddset(&set, SIGTERM) ;
-      sigaddset(&set, SIGHUP) ;
-      sigaddset(&set, SIGQUIT) ;
-      sigaddset(&set, SIGABRT) ;
-      if (selfpipe_trapset(&set) < 0) strerr_diefu1sys(111, "trap signals") ;
+      newargv[m++] = S6_EXTBINPREFIX "s6-applyuidgid" ;
+      if (flagU) newargv[m++] = "-Uz" ;
+      if (uid)
+      {
+        newargv[m++] = "-u" ;
+        newargv[m++] = fmt + pos ;
+        pos += uint_fmt(fmt + pos, uid) ;
+        fmt[pos++] = 0 ;
+      }
+      if (gid)
+      {
+        newargv[m++] = "-g" ;
+        newargv[m++] = fmt + pos ;
+        pos += uint_fmt(fmt + pos, gid) ;
+        fmt[pos++] = 0 ;
+      }
+      if (gidn != (unsigned int)-1)
+      {
+        newargv[m++] = "-G" ;
+        newargv[m++] = fmt + pos ;
+        pos += gid_fmtlist(fmt + pos, gids, gidn) ;
+        fmt[pos++] = 0 ;
+      }
+      newargv[m++] = "--" ;
     }
-    if (flag1)
+    newargv[m++] = S6_NETWORKING_BINPREFIX "s6-tcpserver6d" ;
+    if (verbosity != 1)
     {
-      char fmt[UINT16_FMT] ;
-      unsigned int n = uint16_fmt(fmt, port) ;
-      fmt[n++] = '\n' ;
-      allwrite(1, fmt, n) ;
-      fd_close(1) ;
+      newargv[m++] = "-v" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, verbosity) ;
+      fmt[pos++] = 0 ;
     }
-    fmtlocalmaxconn[1+uint_fmt(fmtlocalmaxconn+1, localmaxconn)] = 0 ;
-    if (verbosity >= 2)
+    if (flag1) newargv[m++] = "-1" ;
+    if (maxconn)
     {
-      fmtmaxconn[1+uint_fmt(fmtmaxconn+1, maxconn)] = 0 ;
-      log_start(ip, port) ;
-      log_status() ;
+      newargv[m++] = "-c" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, maxconn) ;
+      fmt[pos++] = 0 ;
     }
-  }
-
-  {
-    ipnum_t inyostack[maxconn<<1] ;
-    pidip = inyostack ; ipnum = inyostack + maxconn ;
-    while (cont)
+    if (localmaxconn)
     {
-      if (iopause_g(x, 1 + (numconn < maxconn), 0) < 0)
-        strerr_diefu1sys(111, "iopause") ;
-
-      if (x[0].revents & IOPAUSE_EXCEPT) strerr_dief1x(111, "trouble with selfpipe") ;
-      if (x[0].revents & IOPAUSE_READ) handle_signals() ;
-      if (numconn < maxconn)
-      {
-        if (x[1].revents & IOPAUSE_EXCEPT) strerr_dief1x(111, "trouble with socket") ;
-        if (x[1].revents & IOPAUSE_READ)
-        {
-          char ip[16] ;
-          uint16 port ;
-          register int fd = socket_accept6(x[1].fd, ip, &port) ;
-          if (fd < 0)
-          {
-            if (verbosity) strerr_warnwu1sys("accept") ;
-          }
-          else
-          {
-            new_connection(fd, ip, port, argv+2, envp) ;
-            fd_close(fd) ;
-          }
-        }
-      }
+      newargv[m++] = "-C" ;
+      newargv[m++] = fmt + pos ;
+      pos += uint_fmt(fmt + pos, localmaxconn) ;
+      fmt[pos++] = 0 ;
     }
+    newargv[m++] = "--" ;
+    while (*argv) newargv[m++] = *argv++ ;
+    newargv[m++] = 0 ;
+    pathexec_run(newargv[0], newargv, envp) ;
+    strerr_dieexec(111, newargv[0]) ;
   }
-  if (verbosity >= 2) log_exit() ;
-  return 0 ;
 }