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sortix-mirror/kernel/fs/kram.cpp
Jonas 'Sortie' Termansen 2b72262b4f Relicense Sortix to the ISC license. 
I hereby relicense all my work on Sortix under the ISC license as below.

All Sortix contributions by other people are already under this license,
are not substantial enough to be copyrightable, or have been removed.

All imported code from other projects is compatible with this license.

All GPL licensed code from other projects had previously been removed.

Copyright 2011-2016 Jonas 'Sortie' Termansen and contributors.

Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
2016-03-05 22:21:50 +01:00

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/*
* Copyright (c) 2012, 2013, 2014, 2015 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* fs/kram.cpp
* Kernel RAM filesystem.
*/
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <sortix/clock.h>
#include <sortix/dirent.h>
#include <sortix/fcntl.h>
#include <sortix/seek.h>
#include <sortix/stat.h>
#include <sortix/statvfs.h>
#include <sortix/kernel/fsfunc.h>
#include <sortix/kernel/inode.h>
#include <sortix/kernel/interlock.h>
#include <sortix/kernel/ioctx.h>
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/kthread.h>
#include <sortix/kernel/memorymanagement.h>
#include <sortix/kernel/refcount.h>
#include <sortix/kernel/string.h>
#include <sortix/kernel/time.h>
#include "kram.h"
namespace Sortix {
namespace KRAMFS {
static ssize_t common_tcgetblob(ioctx_t* ctx, const char* name, void* buffer, size_t count)
{
if ( !name )
{
static const char index[] = "device-path\0filesystem-type\0";
size_t index_size = sizeof(index) - 1;
if ( buffer && count < index_size )
return errno = ERANGE, -1;
if ( buffer && !ctx->copy_to_dest(buffer, &index, index_size) )
return -1;
return (ssize_t) index_size;
}
else if ( !strcmp(name, "device-path") )
{
const char* data = "none";
size_t size = strlen(data);
if ( buffer && count < size )
return errno = ERANGE, -1;
if ( buffer && !ctx->copy_to_dest(buffer, data, size) )
return -1;
return (ssize_t) size;
}
else if ( !strcmp(name, "filesystem-type") )
{
const char* data = "kram";
size_t size = strlen(data);
if ( buffer && count < size )
return errno = ERANGE, -1;
if ( buffer && !ctx->copy_to_dest(buffer, data, size) )
return -1;
return (ssize_t) size;
}
else
return errno = ENOENT, -1;
}
int common_statvfs(ioctx_t* ctx, struct statvfs* stvfs, dev_t dev)
{
size_t memory_used;
size_t memory_total;
Memory::Statistics(&memory_used, &memory_total);
struct statvfs retstvfs;
memset(&retstvfs, 0, sizeof(retstvfs));
retstvfs.f_bsize = Page::Size();
retstvfs.f_frsize = Page::Size();
retstvfs.f_blocks = memory_total / Page::Size();
retstvfs.f_bfree = (memory_total - memory_used) / Page::Size();
retstvfs.f_bavail = (memory_total - memory_used) / Page::Size();
retstvfs.f_files = 0;
retstvfs.f_ffree = 0;
retstvfs.f_favail = 0;
retstvfs.f_fsid = dev;
retstvfs.f_flag = ST_NOSUID;
retstvfs.f_namemax = ULONG_MAX;
if ( !ctx->copy_to_dest(stvfs, &retstvfs, sizeof(retstvfs)) )
return -1;
return 0;
}
File::File(InodeType inode_type, mode_t type, dev_t dev, ino_t ino, uid_t owner,
gid_t group, mode_t mode)
{
this->inode_type = inode_type;
if ( !dev )
dev = (dev_t) this;
if ( !ino )
ino = (ino_t) this;
this->type = type;
this->stat_uid = owner;
this->stat_gid = group;
this->stat_mode = (mode & S_SETABLE) | this->type;
this->stat_size = 0;
this->stat_blksize = 1;
this->dev = dev;
this->ino = ino;
}
File::~File()
{
}
int File::truncate(ioctx_t* ctx, off_t length)
{
int ret = fcache.truncate(ctx, length);
if ( ret == 0 )
{
ScopedLock lock(&metalock);
stat_size = fcache.GetFileSize();
stat_mtim = Time::Get(CLOCK_REALTIME);
}
return ret;
}
off_t File::lseek(ioctx_t* ctx, off_t offset, int whence)
{
return fcache.lseek(ctx, offset, whence);
}
ssize_t File::pread(ioctx_t* ctx, uint8_t* dest, size_t count, off_t off)
{
return fcache.pread(ctx, dest, count, off);
}
ssize_t File::pwrite(ioctx_t* ctx, const uint8_t* src, size_t count, off_t off)
{
ssize_t ret = fcache.pwrite(ctx, src, count, off);
if ( 0 < ret )
{
ScopedLock lock(&metalock);
stat_size = fcache.GetFileSize();
stat_mtim = Time::Get(CLOCK_REALTIME);
}
return ret;
}
ssize_t File::readlink(ioctx_t* ctx, char* buf, size_t bufsize)
{
if ( !S_ISLNK(type) )
return errno = EINVAL, -1;
if ( (size_t) SSIZE_MAX < bufsize )
bufsize = SSIZE_MAX;
return fcache.pread(ctx, (uint8_t*) buf, bufsize, 0);
}
ssize_t File::tcgetblob(ioctx_t* ctx, const char* name, void* buffer, size_t count)
{
return common_tcgetblob(ctx, name, buffer, count);
}
int File::statvfs(ioctx_t* ctx, struct statvfs* stvfs)
{
return common_statvfs(ctx, stvfs, dev);
}
Dir::Dir(dev_t dev, ino_t ino, uid_t owner, gid_t group, mode_t mode)
{
inode_type = INODE_TYPE_DIR;
if ( !dev )
dev = (dev_t) this;
if ( !ino )
ino = (ino_t) this;
dir_lock = KTHREAD_MUTEX_INITIALIZER;
this->stat_gid = owner;
this->stat_gid = group;
this->type = S_IFDIR;
this->stat_mode = (mode & S_SETABLE) | this->type;
this->dev = dev;
this->ino = ino;
children_used = 0;
children_length = 0;
children = NULL;
shut_down = false;
}
Dir::~Dir()
{
// We must not be deleted or garbage collected if we are still used by
// someone. In that case the deleter should either delete our children or
// simply forget about us.
assert(!children_used);
delete[] children;
}
ssize_t Dir::readdirents(ioctx_t* ctx, struct dirent* dirent, size_t size,
off_t start)
{
ScopedLock lock(&dir_lock);
if ( children_used <= (uintmax_t) start )
return 0;
struct dirent retdirent;
memset(&retdirent, 0, sizeof(retdirent));
const char* name = children[start].name;
size_t namelen = strlen(name);
Ref<Inode> inode = children[start].inode;
retdirent.d_reclen = sizeof(*dirent) + namelen + 1;
retdirent.d_namlen = namelen;
retdirent.d_ino = inode->ino;
retdirent.d_dev = inode->dev;
retdirent.d_type = ModeToDT(inode->type);
if ( !ctx->copy_to_dest(dirent, &retdirent, sizeof(retdirent)) )
return -1;
if ( size < retdirent.d_reclen )
return errno = ERANGE, -1;
if ( !ctx->copy_to_dest(dirent->d_name, name, namelen+1) )
return -1;
return (ssize_t) retdirent.d_reclen;
}
size_t Dir::FindChild(const char* filename)
{
for ( size_t i = 0; i < children_used; i++ )
if ( !strcmp(filename, children[i].name) )
return i;
return SIZE_MAX;
}
bool Dir::AddChild(const char* filename, Ref<Inode> inode)
{
if ( children_used == children_length )
{
size_t new_children_length = children_length ? 2 * children_length : 4;
DirEntry* new_children = new DirEntry[new_children_length];
if ( !new_children )
return false;
for ( size_t i = 0; i < children_used; i++ )
{
new_children[i].inode = children[i].inode;
new_children[i].name = children[i].name;
children[i].inode.Reset();
}
delete[] children; children = new_children;
children_length = new_children_length;
}
char* filename_copy = String::Clone(filename);
if ( !filename_copy )
return false;
inode->linked();
DirEntry* dirent = &children[children_used++];
dirent->inode = inode;
dirent->name = filename_copy;
return true;
}
void Dir::RemoveChild(size_t index)
{
assert(index < children_used);
if ( index != children_used-1 )
{
DirEntry tmp = children[index];
children[index] = children[children_used-1];
children[children_used-1] = tmp;
index = children_used-1;
}
children[index].inode.Reset();
delete[] children[index].name;
children_used--;
}
Ref<Inode> Dir::open(ioctx_t* ctx, const char* filename, int flags, mode_t mode)
{
ScopedLock lock(&dir_lock);
if ( shut_down )
return errno = ENOENT, Ref<Inode>(NULL);
size_t child_index = FindChild(filename);
if ( child_index != SIZE_MAX )
{
if ( (flags & O_CREATE) && (flags & O_EXCL) )
return errno = EEXIST, Ref<Inode>(NULL);
return children[child_index].inode;
}
if ( !(flags & O_CREATE) )
return errno = ENOENT, Ref<Inode>(NULL);
Ref<File> file(new File(INODE_TYPE_FILE, S_IFREG, dev, 0, ctx->uid,
ctx->gid, mode));
if ( !file )
return Ref<Inode>(NULL);
if ( !AddChild(filename, file) )
return Ref<Inode>(NULL);
return file;
}
int Dir::mkdir(ioctx_t* ctx, const char* filename, mode_t mode)
{
ScopedLock lock(&dir_lock);
if ( shut_down )
return errno = ENOENT, -1;
size_t child_index = FindChild(filename);
if ( child_index != SIZE_MAX )
return errno = EEXIST, -1;
Ref<Dir> dir(new Dir(dev, 0, ctx->uid, ctx->gid, mode));
if ( !dir )
goto cleanup_done;
if ( dir->link_raw(ctx, ".", dir) )
goto cleanup_done;
if ( dir->link_raw(ctx, "..", Ref<Dir>(this)) )
goto cleanup_dot;
if ( !AddChild(filename, dir) )
goto cleanup_dotdot;
return 0;
cleanup_dotdot:
dir->unlink_raw(ctx, "..");
cleanup_dot:
dir->unlink_raw(ctx, ".");
cleanup_done:
return -1;
}
int Dir::rmdir(ioctx_t* ctx, const char* filename)
{
if ( IsDotOrDotDot(filename) )
return errno = ENOTEMPTY, -1;
ScopedLock lock(&dir_lock);
if ( shut_down )
return errno = ENOENT, -1;
size_t child_index = FindChild(filename);
if ( child_index == SIZE_MAX )
return errno = ENOENT, -1;
Inode* child = children[child_index].inode.Get();
if ( !S_ISDIR(child->type) )
return errno = ENOTDIR, -1;
if ( child->rmdir_me(ctx) < 0 )
return -1;
RemoveChild(child_index);
return 0;
}
int Dir::rmdir_me(ioctx_t* /*ctx*/)
{
ScopedLock lock(&dir_lock);
if ( shut_down )
return errno = ENOENT, -1;
for ( size_t i = 0; i < children_used; i++ )
if ( !IsDotOrDotDot(children[i].name) )
return errno = ENOTEMPTY, -1;
shut_down = true;
for ( size_t i = 0; i < children_used; i++ )
{
children[i].inode->unlinked();
children[i].inode.Reset();
delete[] children[i].name;
}
delete[] children; children = NULL;
children_used = children_length = 0;
return 0;
}
int Dir::link(ioctx_t* /*ctx*/, const char* filename, Ref<Inode> node)
{
if ( S_ISDIR(node->type) )
return errno = EPERM, -1;
// TODO: Is this needed? This may protect against file descriptors to
// deleted directories being used to corrupt kernel state, or something.
if ( IsDotOrDotDot(filename) )
return errno = EEXIST, -1;
if ( node->dev != dev )
return errno = EXDEV, -1;
ScopedLock lock(&dir_lock);
if ( shut_down )
return errno = ENOENT, -1;
size_t child_index = FindChild(filename);
if ( child_index != SIZE_MAX )
return errno = EEXIST, -1;
if ( !AddChild(filename, node) )
return -1;
return 0;
}
int Dir::link_raw(ioctx_t* /*ctx*/, const char* filename, Ref<Inode> node)
{
if ( node->dev != dev )
return errno = EXDEV, -1;
ScopedLock lock(&dir_lock);
size_t child_index = FindChild(filename);
if ( child_index != SIZE_MAX )
{
children[child_index].inode->unlinked();
children[child_index].inode = node;
children[child_index].inode->linked();
}
else
{
if ( !AddChild(filename, node) )
return -1;
}
return 0;
}
int Dir::unlink(ioctx_t* /*ctx*/, const char* filename)
{
ScopedLock lock(&dir_lock);
if ( shut_down )
return errno = ENOENT, -1;
size_t child_index = FindChild(filename);
if ( child_index == SIZE_MAX )
return errno = ENOENT, -1;
Inode* child = children[child_index].inode.Get();
if ( S_ISDIR(child->type) )
return errno = EISDIR, -1;
RemoveChild(child_index);
return 0;
}
int Dir::unlink_raw(ioctx_t* /*ctx*/, const char* filename)
{
ScopedLock lock(&dir_lock);
size_t child_index = FindChild(filename);
if ( child_index == SIZE_MAX )
return errno = ENOENT, -1;
RemoveChild(child_index);
return 0;
}
int Dir::symlink(ioctx_t* ctx, const char* oldname, const char* filename)
{
ScopedLock lock(&dir_lock);
if ( shut_down )
return errno = ENOENT, -1;
if ( FindChild(filename) != SIZE_MAX )
return errno = EEXIST, -1;
Ref<File> file(new File(INODE_TYPE_SYMLINK, S_IFLNK, dev, 0, ctx->uid,
ctx->gid, 0777));
if ( !file )
return Ref<Inode>(NULL);
ioctx_t kctx;
SetupKernelIOCtx(&kctx);
size_t oldname_length = strlen(oldname);
size_t so_far = 0;
while ( so_far < oldname_length )
{
#if OFF_MAX < SIZE_MAX
if ( (uintmax_t) OFF_MAX < (uintmax_t) so_far )
return Ref<Inode>(NULL);
#endif
ssize_t amount = file->pwrite(&kctx, (const uint8_t*) oldname + so_far,
oldname_length - so_far, (off_t) so_far);
if ( amount <= 0 )
return Ref<Inode>(NULL);
so_far += (size_t) amount;
}
if ( !AddChild(filename, file) )
return Ref<Inode>(NULL);
return 0;
}
int Dir::rename_here(ioctx_t* ctx, Ref<Inode> from, const char* oldname,
const char* newname)
{
if ( IsDotOrDotDot(oldname) || IsDotOrDotDot(newname) )
return errno = EINVAL, -1;
// TODO: Check whether oldpath is an ancestor of newpath.
// Avoid deadlocks by locking directories in the right order.
Dir* from_dir = (Dir*) from.Get();
kthread_mutex_t* mutex_ptr1;
kthread_mutex_t* mutex_ptr2;
if ( from_dir->ino < this->ino )
{
mutex_ptr1 = &from_dir->dir_lock;
mutex_ptr2 = &this->dir_lock;
}
else if ( from_dir->ino == this->ino )
{
mutex_ptr1 = &this->dir_lock,
mutex_ptr2 = NULL;
if ( !strcmp(oldname, newname) )
return 0;
}
else
{
mutex_ptr1 = &this->dir_lock;
mutex_ptr2 = &from_dir->dir_lock;
}
ScopedLock lock1(mutex_ptr1);
ScopedLock lock2(mutex_ptr2);
size_t from_index = from_dir->FindChild(oldname);
if ( from_index == SIZE_MAX )
return errno = ENOENT, -1;
Ref<Inode> the_inode = from_dir->children[from_index].inode;
size_t to_index = this->FindChild(newname);
if ( to_index != SIZE_MAX )
{
Ref<Inode> existing = this->children[to_index].inode;
if ( existing->dev == the_inode->dev &&
existing->ino == the_inode->ino )
return 0;
if ( S_ISDIR(existing->type) )
{
Dir* existing_dir = (Dir*) existing.Get();
if ( !S_ISDIR(the_inode->type) )
return errno = EISDIR, -1;
assert(&existing_dir->dir_lock != mutex_ptr1);
assert(&existing_dir->dir_lock != mutex_ptr2);
if ( existing_dir->rmdir_me(ctx) != 0 )
return -1;
}
this->children[to_index].inode = the_inode;
}
else
{
if ( !this->AddChild(newname, the_inode) )
return -1;
}
from_dir->RemoveChild(from_index);
if ( S_ISDIR(the_inode->type) )
the_inode->link_raw(ctx, "..", Ref<Inode>(this));
return 0;
}
ssize_t Dir::tcgetblob(ioctx_t* ctx, const char* name, void* buffer, size_t count)
{
return common_tcgetblob(ctx, name, buffer, count);
}
int Dir::statvfs(ioctx_t* ctx, struct statvfs* stvfs)
{
return common_statvfs(ctx, stvfs, dev);
}
} // namespace KRAMFS
} // namespace Sortix
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