Use the smarter filedescriptor closing in bpipe.

Instead of closing the filedescriptors ourself (and a maximum
of 29 (32 - 3)) use fcntl(F_CLOSEM) or closefrom() library call
to perform what we really want e.g. close all unneeded filedescriptors
of the forked process.

src/lib/bpipe.c

@@ -127,9 +127,23 @@ BPIPE *open_bpipe(char *prog, int wait, const char *mode)
       }
 /* Note, the close log cause problems, see bug #1536 */
 /*    closelog();                        close syslog if open */
-      for (i=3; i<=32; i++) {         /* close any open file descriptors */
+
+#if defined(HAVE_FCNTL_F_CLOSEM)
+      /*
+       * fcntl(fd, F_CLOSEM) needs the lowest filedescriptor to close.
+       */
+      fcntl(3, F_CLOSEM);
+#elif defined(HAVE_CLOSEFROM)
+      /*
+       * closefrom needs the lowest filedescriptor to close.
+       */
+      closefrom(3);
+#else
+      for (i = 3; i <= 32; i++) {         /* close any open file descriptors */
          close(i);
       }
+#endif
+
       execvp(bargv[0], bargv);        /* call the program */
       /* Convert errno into an exit code for later analysis */
       for (i=0; i< num_execvp_errors; i++) {

src/lib/daemon.c

@@ -70,15 +70,15 @@ daemon_start()
 
 #if defined(HAVE_FCNTL_F_CLOSEM)
    /*
-    * fcntl(fd, F_CLOSEM) needs the minimum filedescriptor
+    * fcntl(fd, F_CLOSEM) needs the lowest filedescriptor
     * to close. the current code sets the last one to keep
     * open. So increment it with 1 and use that as argument.
     */
    low_fd++;
    fcntl(low_fd, F_CLOSEM);
 #elif defined(HAVE_CLOSEFROM)
    /*
-    * closefrom needs the minimum filedescriptor to close.
+    * closefrom needs the lowest filedescriptor to close.
     * the current code sets the last one to keep open.
     * So increment it with 1 and use that as argument.
     */