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https://gitlab.com/sortix/sortix.git
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1e671aa8cd
The d_off field exists on other operating systems and the kernel used the field in an incompatible manner. The easy solution is to call the field something else and later address the design mistake.
434 lines
11 KiB
C++
434 lines
11 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2012, 2013.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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fs/kram.cpp
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Kernel RAM filesystem.
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*******************************************************************************/
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#include <sys/types.h>
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#include <assert.h>
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#include <errno.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <string.h>
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#include <sortix/clock.h>
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#include <sortix/dirent.h>
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#include <sortix/fcntl.h>
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#include <sortix/seek.h>
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#include <sortix/stat.h>
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#include <sortix/kernel/fsfunc.h>
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#include <sortix/kernel/inode.h>
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#include <sortix/kernel/interlock.h>
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#include <sortix/kernel/ioctx.h>
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#include <sortix/kernel/kernel.h>
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#include <sortix/kernel/kthread.h>
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#include <sortix/kernel/refcount.h>
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#include <sortix/kernel/string.h>
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#include <sortix/kernel/time.h>
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#include "kram.h"
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namespace Sortix {
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namespace KRAMFS {
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File::File(dev_t dev, ino_t ino, uid_t owner, gid_t group, mode_t mode)
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{
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inode_type = INODE_TYPE_FILE;
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if ( !dev )
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dev = (dev_t) this;
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if ( !ino )
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ino = (ino_t) this;
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this->type = S_IFREG;
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this->stat_uid = owner;
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this->stat_gid = group;
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this->stat_mode = (mode & S_SETABLE) | this->type;
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this->stat_size = 0;
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this->stat_blksize = 1;
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this->dev = dev;
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this->ino = ino;
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}
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File::~File()
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{
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}
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int File::truncate(ioctx_t* ctx, off_t length)
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{
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int ret = fcache.truncate(ctx, length);
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if ( ret == 0 )
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{
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ScopedLock lock(&metalock);
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stat_size = fcache.GetFileSize();
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stat_mtim = Time::Get(CLOCK_REALTIME);
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}
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return ret;
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}
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off_t File::lseek(ioctx_t* ctx, off_t offset, int whence)
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{
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return fcache.lseek(ctx, offset, whence);
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}
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ssize_t File::pread(ioctx_t* ctx, uint8_t* dest, size_t count, off_t off)
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{
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return fcache.pread(ctx, dest, count, off);
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}
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ssize_t File::pwrite(ioctx_t* ctx, const uint8_t* src, size_t count, off_t off)
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{
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ssize_t ret = fcache.pwrite(ctx, src, count, off);
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if ( 0 < ret )
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{
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ScopedLock lock(&metalock);
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stat_size = fcache.GetFileSize();
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stat_mtim = Time::Get(CLOCK_REALTIME);
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}
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return ret;
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}
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Dir::Dir(dev_t dev, ino_t ino, uid_t owner, gid_t group, mode_t mode)
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{
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inode_type = INODE_TYPE_DIR;
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if ( !dev )
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dev = (dev_t) this;
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if ( !ino )
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ino = (ino_t) this;
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dirlock = KTHREAD_MUTEX_INITIALIZER;
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this->stat_gid = owner;
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this->stat_gid = group;
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this->type = S_IFDIR;
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this->stat_mode = (mode & S_SETABLE) | this->type;
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this->dev = dev;
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this->ino = ino;
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numchildren = 0;
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childrenlen = 0;
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children = NULL;
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shutdown = false;
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}
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Dir::~Dir()
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{
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// We must not be deleted or garbage collected if we are still used by
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// someone. In that case the deleter should either delete our children or
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// simply forget about us.
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assert(!numchildren);
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delete[] children;
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}
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ssize_t Dir::readdirents(ioctx_t* ctx, struct kernel_dirent* dirent,
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size_t size, off_t start, size_t /*maxcount*/)
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{
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ScopedLock lock(&dirlock);
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if ( numchildren <= (uintmax_t) start )
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return 0;
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struct kernel_dirent retdirent;
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memset(&retdirent, 0, sizeof(retdirent));
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const char* name = children[start].name;
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size_t namelen = strlen(name);
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size_t needed = sizeof(*dirent) + namelen + 1;
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ssize_t ret = -1;
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if ( size < needed )
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{
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errno = ERANGE;
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retdirent.d_namlen = namelen;
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}
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else
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{
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Ref<Inode> inode = children[start].inode;
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ret = needed;
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retdirent.d_reclen = needed;
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retdirent.d_nextoff = 0;
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retdirent.d_namlen = namelen;
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retdirent.d_ino = inode->ino;
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retdirent.d_dev = inode->dev;
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retdirent.d_type = ModeToDT(inode->type);
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}
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if ( !ctx->copy_to_dest(dirent, &retdirent, sizeof(retdirent)) )
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return -1;
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if ( 0 <= ret && !ctx->copy_to_dest(dirent->d_name, name, namelen+1) )
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return -1;
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return ret;
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}
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size_t Dir::FindChild(const char* filename)
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{
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for ( size_t i = 0; i < numchildren; i++ )
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if ( !strcmp(filename, children[i].name) )
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return i;
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return SIZE_MAX;
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}
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bool Dir::AddChild(const char* filename, Ref<Inode> inode)
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{
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if ( numchildren == childrenlen )
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{
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size_t newchildrenlen = childrenlen ? 2 * childrenlen : 4;
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DirEntry* newchildren = new DirEntry[newchildrenlen];
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if ( !newchildren )
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return false;
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for ( size_t i = 0; i < numchildren; i++ )
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newchildren[i].inode = children[i].inode,
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newchildren[i].name = children[i].name;
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delete[] children; children = newchildren;
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childrenlen = newchildrenlen;
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}
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char* filenamecopy = String::Clone(filename);
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if ( !filenamecopy )
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return false;
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inode->linked();
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DirEntry* dirent = children + numchildren++;
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dirent->inode = inode;
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dirent->name = filenamecopy;
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return true;
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}
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void Dir::RemoveChild(size_t index)
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{
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assert(index < numchildren);
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if ( index != numchildren-1 )
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{
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DirEntry tmp = children[index];
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children[index] = children[numchildren-1];
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children[numchildren-1] = tmp;
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index = numchildren-1;
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}
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children[index].inode.Reset();
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delete[] children[index].name;
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numchildren--;
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}
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Ref<Inode> Dir::open(ioctx_t* ctx, const char* filename, int flags, mode_t mode)
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{
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ScopedLock lock(&dirlock);
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if ( shutdown ) { errno = ENOENT; return Ref<Inode>(NULL); }
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size_t childindex = FindChild(filename);
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if ( childindex != SIZE_MAX )
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{
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if ( flags & O_EXCL ) { errno = EEXIST; return Ref<Inode>(NULL); }
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return children[childindex].inode;
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}
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if ( !(flags & O_CREATE) )
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return errno = ENOENT, Ref<Inode>(NULL);
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Ref<File> file(new File(dev, 0, ctx->uid, ctx->gid, mode));
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if ( !file )
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return Ref<Inode>(NULL);
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if ( !AddChild(filename, file) )
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return Ref<Inode>(NULL);
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return file;
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}
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int Dir::mkdir(ioctx_t* ctx, const char* filename, mode_t mode)
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{
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ScopedLock lock(&dirlock);
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if ( shutdown ) { errno = ENOENT; return -1; }
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size_t childindex = FindChild(filename);
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if ( childindex != SIZE_MAX ) { errno = EEXIST; return -1; }
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Ref<Dir> dir(new Dir(dev, 0, ctx->uid, ctx->gid, mode));
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if ( !dir )
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goto cleanup_done;
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if ( dir->link_raw(ctx, ".", dir) )
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goto cleanup_done;
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if ( dir->link_raw(ctx, "..", Ref<Dir>(this)) )
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goto cleanup_dot;
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if ( !AddChild(filename, dir) )
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goto cleanup_dotdot;
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return 0;
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cleanup_dotdot:
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dir->unlink_raw(ctx, "..");
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cleanup_dot:
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dir->unlink_raw(ctx, ".");
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cleanup_done:
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return -1;
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}
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int Dir::rmdir(ioctx_t* ctx, const char* filename)
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{
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if ( IsDotOrDotDot(filename) ) { errno = ENOTEMPTY; return -1; }
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ScopedLock lock(&dirlock);
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if ( shutdown ) { errno = ENOENT; return -1; }
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size_t childindex = FindChild(filename);
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if ( childindex == SIZE_MAX ) { errno = ENOENT; return -1; }
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Inode* child = children[childindex].inode.Get();
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if ( !S_ISDIR(child->type) ) { errno = ENOTDIR; return -1; }
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if ( child->rmdir_me(ctx) < 0 ) { return -1; }
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RemoveChild(childindex);
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return 0;
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}
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int Dir::rmdir_me(ioctx_t* /*ctx*/)
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{
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ScopedLock lock(&dirlock);
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if ( shutdown ) { errno = ENOENT; return -1; }
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for ( size_t i = 0; i < numchildren; i++ )
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if ( !IsDotOrDotDot(children[i].name) )
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return errno = ENOTEMPTY, -1;
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shutdown = true;
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for ( size_t i = 0; i < numchildren; i++ )
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{
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children[i].inode->unlinked();
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children[i].inode.Reset();
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delete[] children[i].name;
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}
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delete[] children; children = NULL;
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numchildren = childrenlen = 0;
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return 0;
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}
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int Dir::link(ioctx_t* /*ctx*/, const char* filename, Ref<Inode> node)
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{
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if ( S_ISDIR(node->type) ) { errno = EPERM; return -1; }
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// TODO: Is this needed? This may protect against file descriptors to
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// deleted directories being used to corrupt kernel state, or something.
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if ( IsDotOrDotDot(filename) ) { errno = EEXIST; return -1; }
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if ( node->dev != dev ) { errno = EXDEV; return -1; }
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ScopedLock lock(&dirlock);
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if ( shutdown ) { errno = ENOENT; return -1; }
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size_t childindex = FindChild(filename);
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if ( childindex != SIZE_MAX )
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{
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errno = EEXIST;
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return -1;
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}
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else
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if ( !AddChild(filename, node) )
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return -1;
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return 0;
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}
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int Dir::link_raw(ioctx_t* /*ctx*/, const char* filename, Ref<Inode> node)
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{
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if ( node->dev != dev ) { errno = EXDEV; return -1; }
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ScopedLock lock(&dirlock);
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size_t childindex = FindChild(filename);
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if ( childindex != SIZE_MAX )
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{
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children[childindex].inode->unlinked();
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children[childindex].inode = node;
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children[childindex].inode->linked();
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}
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else
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if ( !AddChild(filename, node) )
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return -1;
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return 0;
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}
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int Dir::unlink(ioctx_t* /*ctx*/, const char* filename)
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{
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ScopedLock lock(&dirlock);
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if ( shutdown ) { errno = ENOENT; return -1; }
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size_t childindex = FindChild(filename);
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if ( childindex == SIZE_MAX ) { errno = ENOENT; return -1; }
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Inode* child = children[childindex].inode.Get();
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if ( S_ISDIR(child->type) ) { errno = EISDIR; return -1; }
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RemoveChild(childindex);
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return 0;
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}
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int Dir::unlink_raw(ioctx_t* /*ctx*/, const char* filename)
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{
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ScopedLock lock(&dirlock);
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size_t childindex = FindChild(filename);
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if ( childindex == SIZE_MAX ) { errno = ENOENT; return -1; }
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RemoveChild(childindex);
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return 0;
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}
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int Dir::symlink(ioctx_t* /*ctx*/, const char* oldname, const char* filename)
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{
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ScopedLock lock(&dirlock);
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if ( shutdown ) { errno = ENOENT; return -1; }
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(void) oldname;
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(void) filename;
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errno = ENOSYS;
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return -1;
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}
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int Dir::rename_here(ioctx_t* ctx, Ref<Inode> from, const char* oldname,
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const char* newname)
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{
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if ( IsDotOrDotDot(oldname) || IsDotOrDotDot(newname) )
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return errno = EINVAL, -1;
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// TODO: Check whether oldpath is an ancestor of newpath.
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// Avoid deadlocks by locking directories in the right order.
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Dir* from_dir = (Dir*) from.Get();
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kthread_mutex_t* mutex_ptr1;
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kthread_mutex_t* mutex_ptr2;
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if ( from_dir->ino < this->ino )
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mutex_ptr1 = &from_dir->dirlock,
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mutex_ptr2 = &this->dirlock;
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else if ( from_dir->ino == this->ino )
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{
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mutex_ptr1 = &this->dirlock,
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mutex_ptr2 = NULL;
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if ( !strcmp(oldname, newname) )
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return 0;
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}
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else
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mutex_ptr1 = &this->dirlock,
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mutex_ptr2 = &from_dir->dirlock;
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ScopedLock lock1(mutex_ptr1);
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ScopedLock lock2(mutex_ptr2);
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size_t from_index = from_dir->FindChild(oldname);
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if ( from_index == SIZE_MAX )
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return errno = ENOENT, -1;
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Ref<Inode> the_inode = from_dir->children[from_index].inode;
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size_t to_index = this->FindChild(newname);
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if ( to_index != SIZE_MAX )
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{
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Ref<Inode> existing = this->children[to_index].inode;
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if ( existing->dev == the_inode->dev &&
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existing->ino == the_inode->ino )
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return 0;
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if ( S_ISDIR(existing->type) )
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{
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Dir* existing_dir = (Dir*) existing.Get();
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if ( !S_ISDIR(the_inode->type) )
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return errno = EISDIR, -1;
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assert(&existing_dir->dirlock != mutex_ptr1);
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assert(&existing_dir->dirlock != mutex_ptr2);
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if ( existing_dir->rmdir_me(ctx) != 0 )
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return -1;
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}
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this->children[to_index].inode = the_inode;
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}
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else
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if ( !this->AddChild(newname, the_inode) )
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return -1;
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from_dir->RemoveChild(from_index);
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if ( S_ISDIR(the_inode->type) )
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the_inode->link_raw(ctx, "..", Ref<Inode>(this));
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return 0;
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}
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} // namespace KRAMFS
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} // namespace Sortix
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