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/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "nacl_mounts/kernel_handle.h"
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#ifndef WIN32
// Needed for SEEK_SET/SEEK_CUR/SEEK_END.
#include <unistd.h>
#endif
#include "nacl_mounts/mount.h"
#include "nacl_mounts/mount_node.h"
// It is only legal to construct a handle while the kernel lock is held.
KernelHandle::KernelHandle(Mount* mnt, MountNode* node, int mode)
: mount_(mnt),
node_(node),
mode_(mode),
offs_(0) {
if (mode & O_APPEND) offs_ = node->GetSize();
}
off_t KernelHandle::Seek(off_t offset, int whence) {
size_t base;
switch (whence) {
default: return -1;
case SEEK_SET: base = 0; break;
case SEEK_CUR: base = offs_; break;
case SEEK_END: base = node_->GetSize(); break;
}
if (base + offset < 0) {
errno = EINVAL;
return -1;
}
offs_ = base + offset;
// Seeking past the end of the file will zero out the space between the old
// end and the new end.
if (offs_ > node_->GetSize()) {
if (node_->Truncate(offs_) < 0) {
errno = EINVAL;
return -1;
}
}
return offs_;
}
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