util-vserver-0.30.208

[util-vserver.git] / src / context-sync.hc

diff --git a/src/context-sync.hc b/src/context-sync.hc
new file mode 100644 (file)
index 0000000..6f786d5
--- /dev/null
+++ b/src/context-sync.hc
@@ -0,0 +1,89 @@
+// $Id: context-sync.hc,v 1.5 2005/04/10 01:01:33 ensc Exp $    --*- c -*--
+
+// Copyright (C) 2004 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
+//  
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; version 2 of the License.
+//  
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//  
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+
+/// \args p[0]  used for parent -> child sync (child waits till parent is in deathrow)
+/// \args p[1]  used for child -> parent sync (recognize execv() errors)
+static inline ALWAYSINLINE int
+initSync(int p[2][2], bool do_disconnect)
+{
+  if (!do_disconnect) return 0;
+
+  Epipe(p[0]);
+  Epipe(p[1]);
+  fcntl(p[1][1], F_SETFD, FD_CLOEXEC);
+  return Efork();
+}
+
+static inline ALWAYSINLINE void
+doSyncStage0(int p[2][2], bool do_disconnect)
+{
+  char         c;
+  if (!do_disconnect) return;
+
+  Eclose(p[0][1]);
+  Eread (p[0][0], &c, 1);
+  Eclose(p[0][0]);
+}
+
+static inline ALWAYSINLINE void
+doSyncStage1(int p[2][2], bool do_disconnect)
+{
+  int  fd;
+
+  if (!do_disconnect) return;
+  
+  fd = EopenD("/dev/null", O_RDONLY|O_NONBLOCK, 0);
+  (void)setsid();      // ignore error when we are already a session-leader
+  Edup2(fd, 0);
+  Eclose(p[1][0]);
+  if (fd!=0) Eclose(fd);
+  Ewrite(p[1][1], ".", 1);
+}
+
+static inline ALWAYSINLINE void
+doSyncStage2(int p[2][2], bool do_disconnect)
+{
+  if (!do_disconnect) return;
+
+  Ewrite(p[1][1], "X", 1);
+}
+
+/// \args p[0]  used for parent -> child sync (child waits till parent is in deathrow)
+/// \args p[1]  used for child -> parent sync (recognize execv() errors)
+static void
+waitOnSync(pid_t pid, int p[2][2], bool is_prevent_race)
+{
+  char         c;
+  size_t       l;
+
+  if (is_prevent_race &&
+      !jailIntoTempDir(0)) {
+    perror(ENSC_WRAPPERS_PREFIX "jailIntoTempDir()");
+    exit(255);
+  }
+
+  Eclose(p[0][0]);
+  Ewrite(p[0][1], "X", 1);
+  Eclose(p[0][1]);
+  
+  Eclose(p[1][1]);
+  l = Eread(p[1][0], &c, 1);
+  if (l!=1) exitLikeProcess(pid,0, wrapper_exit_code);
+  l = Eread(p[1][0], &c, 1);
+  if (l!=0) exitLikeProcess(pid,0, wrapper_exit_code);
+}