1 /*
   2  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 #include "jni.h"
  27 #include "jni_util.h"
  28 #include "jvm.h"
  29 #include "io_util.h"
  30 #include "io_util_md.h"
  31 #include <string.h>
  32 
  33 void
  34 fileOpen(JNIEnv *env, jobject this, jstring path, jfieldID fid, int flags)
  35 {
  36     WITH_PLATFORM_STRING(env, path, ps) {
  37         FD fd;
  38 
  39 #ifdef __linux__
  40         /* Remove trailing slashes, since the kernel won't */
  41         char *p = (char *)ps + strlen(ps) - 1;
  42         while ((p > ps) && (*p == '/'))
  43             *p-- = '\0';
  44 #endif
  45         fd = JVM_Open(ps, flags, 0666);
  46         if (fd >= 0) {
  47             SET_FD(this, fd, fid);
  48         } else {
  49             throwFileNotFoundException(env, path);
  50         }
  51     } END_PLATFORM_STRING(env, ps);
  52 }
  53 
  54 
  55 void
  56 fileClose(JNIEnv *env, jobject this, jfieldID fid)
  57 {
  58     FD fd = GET_FD(this, fid);
  59     if (fd == -1) {
  60         return;
  61     }
  62 
  63     /* Set the fd to -1 before closing it so that the timing window
  64      * of other threads using the wrong fd (closed but recycled fd,
  65      * that gets re-opened with some other filename) is reduced.
  66      * Practically the chance of its occurance is low, however, we are
  67      * taking extra precaution over here.
  68      */
  69     SET_FD(this, -1, fid);
  70 
  71     /*
  72      * Don't close file descriptors 0, 1, or 2. If we close these stream
  73      * then a subsequent file open or socket will use them. Instead we
  74      * just redirect these file descriptors to /dev/null.
  75      */
  76     if (fd >= STDIN_FILENO && fd <= STDERR_FILENO) {
  77         int devnull = open("/dev/null", O_WRONLY);
  78         if (devnull < 0) {
  79             SET_FD(this, fd, fid); // restore fd
  80             JNU_ThrowIOExceptionWithLastError(env, "open /dev/null failed");
  81         } else {
  82             dup2(devnull, fd);
  83             close(devnull);
  84         }
  85     } else if (JVM_Close(fd) == -1) {
  86         JNU_ThrowIOExceptionWithLastError(env, "close failed");
  87     }
  88 }