Imported Upstream version 0.3.2

[debian/uanytun.git] / src / sysexec.c

diff --git a/src/sysexec.c b/src/sysexec.c
new file mode 100644 (file)
index 0000000..2cea52e
--- /dev/null
+++ b/src/sysexec.c
@@ -0,0 +1,115 @@
+/*
+ *  uAnytun
+ *
+ *  uAnytun is a tiny implementation of SATP. Unlike Anytun which is a full
+ *  featured implementation uAnytun has no support for multiple connections
+ *  or synchronisation. It is a small single threaded implementation intended
+ *  to act as a client on small platforms.
+ *  The secure anycast tunneling protocol (satp) defines a protocol used
+ *  for communication between any combination of unicast and anycast
+ *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
+ *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
+ *  ethernet, ip, arp ...). satp directly includes cryptography and
+ *  message authentication based on the methodes used by SRTP.  It is
+ *  intended to deliver a generic, scaleable and secure solution for
+ *  tunneling and relaying of packets of any protocol.
+ *  
+ *
+ *  Copyright (C) 2007-2008 Christian Pointner <equinox@anytun.org>
+ *
+ *  This file is part of uAnytun.
+ *
+ *  uAnytun 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, either version 3 of the License, or
+ *  any later version.
+ *
+ *  uAnytun 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 uAnytun. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "datatypes.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <sys/select.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sysexec.h"
+#include "log.h"
+
+int uanytun_exec(const char* script, char* const argv[], char* const evp[])
+{
+  if(!script)
+    return -1;
+
+  int pipefd[2];
+  if(pipe(pipefd) == -1) {
+    log_printf(ERROR, "executing script '%s' pipe() error: %s", script, strerror(errno));
+    return -1;
+  }
+
+  pid_t pid;
+  pid = fork();
+  if(pid == -1) {
+    log_printf(ERROR, "executing script '%s' fork() error: %s", script, strerror(errno));
+    return -1;
+  }
+
+  if(!pid) {
+    int fd;
+    for (fd=getdtablesize();fd>=0;--fd) // close all file descriptors
+      if(fd != pipefd[1]) close(fd);
+
+    fd = open("/dev/null",O_RDWR);        // stdin
+    if(fd == -1)
+      log_printf(WARNING, "can't open stdin");
+    else {
+      if(dup(fd) == -1)   // stdout
+        log_printf(WARNING, "can't open stdout");
+      if(dup(fd) == -1)   // stderr
+        log_printf(WARNING, "can't open stderr");
+    }
+    execve(script, argv, evp);
+        // if execve returns, an error occurred, but logging doesn't work 
+        // because we closed all file descriptors, so just write errno to
+        // pipe and call exit
+    write(pipefd[1], (void*)(&errno), sizeof(errno));
+    exit(-1);
+  }
+  close(pipefd[1]);
+
+  int status = 0;
+  waitpid(pid, &status, 0);
+
+  fd_set rfds;
+  FD_ZERO(&rfds);
+  FD_SET(pipefd[0], &rfds);
+  struct timeval tv = { 0 , 0 };
+  if(select(pipefd[0]+1, &rfds, NULL, NULL, &tv) == 1) {
+    int err = 0;
+    if(read(pipefd[0], (void*)(&err), sizeof(err)) >= sizeof(err)) {
+      log_printf(NOTICE, "script '%s' exec() error: %s", script, strerror(err));
+      close(pipefd[0]);
+      return -1;
+    }
+  }
+  if(WIFEXITED(status))
+    log_printf(NOTICE, "script '%s' returned %d", script, WEXITSTATUS(status));  
+  else if(WIFSIGNALED(status))
+    log_printf(NOTICE, "script '%s' terminated after signal %d", script, WTERMSIG(status));
+  else
+    log_printf(ERROR, "executing script '%s': unkown error", script);
+
+  close(pipefd[0]);
+  return status;
+}