Closing all open file descriptors when calling external programs

HISTORY

@@ -821,3 +821,4 @@ Video Disk Recorder Revision History
 - Removed the "system time seen..." message.
 - Fixed a bug in the replay mode display when pressing the Green or Yellow
   button while in trick mode (thanks to Stefan Huelswitt)
+- Closing all open file descriptors when calling external programs.

recording.c

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: recording.c 1.41 2001/10/19 13:12:17 kls Exp $
+ * $Id: recording.c 1.42 2001/10/20 10:28:28 kls Exp $
  */
 
 #include "recording.h"
@@ -575,7 +575,7 @@ void cRecordingUserCommand::InvokeCommand(const char *State, const char *Recordi
      char *cmd;
      asprintf(&cmd, "%s %s '%s'", command, State, RecordingFileName);
      isyslog(LOG_INFO, "executing '%s'", cmd);
-     system(cmd);
+     SystemExec(cmd);
      delete cmd;
      }
 }

thread.c

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: thread.c 1.13 2001/09/23 14:04:35 kls Exp $
+ * $Id: thread.c 1.14 2001/10/20 10:26:35 kls Exp $
  */
 
 #include "thread.h"
@@ -342,3 +342,35 @@ int cPipe::Close(void)
 
   return ret;
 }
+
+// --- SystemExec ------------------------------------------------------------
+
+int SystemExec(const char *Command)
+{
+  pid_t pid;
+
+  if ((pid = fork()) < 0) { // fork failed
+     LOG_ERROR;
+     return -1;
+     }
+
+  if (pid > 0) { // parent process
+     int status;
+     if (waitpid(pid, &status, 0) < 0) {
+        LOG_ERROR;
+        return -1;
+        }
+     return status;
+     }
+  else { // child process
+     int MaxPossibleFileDescriptors = getdtablesize();
+     for (int i = STDERR_FILENO + 1; i < MaxPossibleFileDescriptors; i++)
+         close(i); //close all dup'ed filedescriptors
+     if (execl("/bin/sh", "sh", "-c", Command, NULL) == -1) {
+        LOG_ERROR_STR(Command);
+        _exit(-1);
+        }
+     _exit(0);
+     }
+}
+

thread.h

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: thread.h 1.9 2001/09/15 12:46:52 kls Exp $
+ * $Id: thread.h 1.10 2001/10/20 10:25:19 kls Exp $
  */
 
 #ifndef __THREAD_H
@@ -104,4 +104,9 @@ public:
   int Close(void);
   };
 
+// SystemExec() implements a 'system()' call that closes all unnecessary file
+// descriptors in the child process.
+
+int SystemExec(const char *Command);
+
 #endif //__THREAD_H

vdr.c

@@ -22,7 +22,7 @@
  *
  * The project's page is at http://www.cadsoft.de/people/kls/vdr
  *
- * $Id: vdr.c 1.84 2001/10/19 13:37:24 kls Exp $
+ * $Id: vdr.c 1.85 2001/10/20 10:26:54 kls Exp $
  */
 
 #include <getopt.h>
@@ -509,7 +509,7 @@ int main(int argc, char *argv[])
                        char *cmd;
                        asprintf(&cmd, "%s %ld %ld %d '%s'", Shutdown, Next, Delta, Channel, File);
                        isyslog(LOG_INFO, "executing '%s'", cmd);
-                       system(cmd);
+                       SystemExec(cmd);
                        delete cmd;
                        }
                     else if (WatchdogTimeout > 0) {