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sortix--sortix/kernel/initrd.cpp
2014-03-01 14:37:39 +01:00

376 lines
11 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013.
This file is part of Sortix.
Sortix is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.
Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details.
You should have received a copy of the GNU General Public License along with
Sortix. If not, see <http://www.gnu.org/licenses/>.
initrd.cpp
Provides low-level access to a Sortix init ramdisk.
*******************************************************************************/
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <timespec.h>
#include <sortix/fcntl.h>
#include <sortix/initrd.h>
#include <sortix/mman.h>
#include <sortix/stat.h>
#include <sortix/kernel/addralloc.h>
#include <sortix/kernel/crc32.h>
#include <sortix/kernel/descriptor.h>
#include <sortix/kernel/fsfunc.h>
#include <sortix/kernel/ioctx.h>
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/memorymanagement.h>
#include <sortix/kernel/string.h>
#include <sortix/kernel/syscall.h>
#include <sortix/kernel/vnode.h>
#include "initrd.h"
namespace Sortix {
namespace InitRD {
addralloc_t initrd_addr_alloc;
uint8_t* initrd = NULL;
size_t initrdsize;
const initrd_superblock_t* sb;
__attribute__((unused))
static uint32_t HostModeToInitRD(mode_t mode)
{
uint32_t result = mode & 0777; // Lower 9 bits per POSIX and tradition.
if ( S_ISVTX & mode ) { result |= INITRD_S_ISVTX; }
if ( S_ISSOCK(mode) ) { result |= INITRD_S_IFSOCK; }
if ( S_ISLNK(mode) ) { result |= INITRD_S_IFLNK; }
if ( S_ISREG(mode) ) { result |= INITRD_S_IFREG; }
if ( S_ISBLK(mode) ) { result |= INITRD_S_IFBLK; }
if ( S_ISDIR(mode) ) { result |= INITRD_S_IFDIR; }
if ( S_ISCHR(mode) ) { result |= INITRD_S_IFCHR; }
if ( S_ISFIFO(mode) ) { result |= INITRD_S_IFIFO; }
return result;
}
__attribute__((unused))
static mode_t InitRDModeToHost(uint32_t mode)
{
mode_t result = mode & 0777; // Lower 9 bits per POSIX and tradition.
if ( INITRD_S_ISVTX & mode ) { result |= S_ISVTX; }
if ( INITRD_S_ISSOCK(mode) ) { result |= S_IFSOCK; }
if ( INITRD_S_ISLNK(mode) ) { result |= S_IFLNK; }
if ( INITRD_S_ISREG(mode) ) { result |= S_IFREG; }
if ( INITRD_S_ISBLK(mode) ) { result |= S_IFBLK; }
if ( INITRD_S_ISDIR(mode) ) { result |= S_IFDIR; }
if ( INITRD_S_ISCHR(mode) ) { result |= S_IFCHR; }
if ( INITRD_S_ISFIFO(mode) ) { result |= S_IFIFO; }
return result;
}
uint32_t Root()
{
return sb->root;
}
static const initrd_inode_t* GetInode(uint32_t inode)
{
if ( sb->inodecount <= inode ) { errno = EINVAL; return NULL; }
uint32_t pos = sb->inodeoffset + sb->inodesize * inode;
return (const initrd_inode_t*) (initrd + pos);
}
bool Stat(uint32_t ino, struct stat* st)
{
const initrd_inode_t* inode = GetInode(ino);
if ( !inode ) { return false; }
st->st_ino = ino;
st->st_mode = HostModeToInitRD(inode->mode);
st->st_nlink = inode->nlink;
st->st_uid = inode->uid;
st->st_gid = inode->gid;
st->st_size = inode->size;
st->st_atim = timespec_make(inode->mtime, 0);
st->st_ctim = timespec_make(inode->ctime, 0);
st->st_mtim = timespec_make(inode->mtime, 0);
st->st_blksize = 1;
st->st_blocks = inode->size;
return true;
}
uint8_t* Open(uint32_t ino, size_t* size)
{
const initrd_inode_t* inode = GetInode(ino);
if ( !inode ) { return NULL; }
*size = inode->size;
return initrd + inode->dataoffset;
}
uint32_t Traverse(uint32_t ino, const char* name)
{
const initrd_inode_t* inode = GetInode(ino);
if ( !inode ) { return 0; }
if ( !INITRD_S_ISDIR(inode->mode) ) { errno = ENOTDIR; return 0; }
uint32_t offset = 0;
while ( offset < inode->size )
{
uint32_t pos = inode->dataoffset + offset;
const initrd_dirent* dirent = (const initrd_dirent*) (initrd + pos);
if ( dirent->namelen && !strcmp(dirent->name, name) )
{
return dirent->inode;
}
offset += dirent->reclen;
}
errno = ENOENT;
return 0;
}
const char* GetFilename(uint32_t dir, size_t index)
{
const initrd_inode_t* inode = GetInode(dir);
if ( !inode ) { return 0; }
if ( !INITRD_S_ISDIR(inode->mode) ) { errno = ENOTDIR; return 0; }
uint32_t offset = 0;
while ( offset < inode->size )
{
uint32_t pos = inode->dataoffset + offset;
const initrd_dirent* dirent = (const initrd_dirent*) (initrd + pos);
if ( index-- == 0 ) { return dirent->name; }
offset += dirent->reclen;
}
errno = EINVAL;
return NULL;
}
size_t GetNumFiles(uint32_t dir)
{
const initrd_inode_t* inode = GetInode(dir);
if ( !inode ) { return 0; }
if ( !INITRD_S_ISDIR(inode->mode) ) { errno = ENOTDIR; return 0; }
uint32_t offset = 0;
size_t numentries = 0;
while ( offset < inode->size )
{
uint32_t pos = inode->dataoffset + offset;
const initrd_dirent* dirent = (const initrd_dirent*) (initrd + pos);
numentries++;
offset += dirent->reclen;
}
return numentries;
}
void CheckSum()
{
uint32_t amount = sb->fssize - sb->sumsize;
uint8_t* filesum = initrd + amount;
if ( sb->sumalgorithm != INITRD_ALGO_CRC32 )
{
Log::PrintF("Warning: InitRD checksum algorithm not supported\n");
return;
}
uint32_t crc32 = *((uint32_t*) filesum);
uint32_t filecrc32 = CRC32::Hash(initrd, amount);
uint32_t doublecheck = CRC32::Hash(initrd, amount);
if ( filecrc32 != doublecheck )
{
// Yes, this has happened. This seems like the goto place for such bugs
// to trigger, so I added a more accurate warning.
Panic("Calculating InitRD checksum two times gave different results: "
"this likely means the kernel have a corruption bug, possibly "
"caused by building libc and kernel with different settings or "
"a bug in the scheduler/interrupt handler or who knows. "
"It is also possible that the laws of logic has changed.");
}
if ( crc32 != filecrc32 )
{
PanicF("InitRD had checksum %X, expected %X: this means the ramdisk "
"may have been corrupted by the bootloader.", filecrc32, crc32);
}
}
void Init(addr_t phys, size_t size)
{
assert(!initrd);
// Allocate the needed kernel virtual address space.
if ( !AllocateKernelAddress(&initrd_addr_alloc, size) )
PanicF("Can't allocate 0x%zx bytes of kernel address space for the "
"init ramdisk", size );
// Map the physical frames onto our address space.
addr_t mapat = initrd_addr_alloc.from;
for ( size_t i = 0; i < size; i += Page::Size() )
if ( !Memory::Map(phys + i, mapat + i, PROT_KREAD) )
Panic("Unable to map the init ramdisk into virtual memory");
Memory::Flush();
initrd = (uint8_t*) mapat;
initrdsize = size;
if ( size < sizeof(*sb) ) { PanicF("initrd is too small"); }
sb = (const initrd_superblock_t*) initrd;
if ( !String::StartsWith(sb->magic, "sortix-initrd") )
{
Panic("Invalid magic value in initrd. This means the ramdisk may have "
"been corrupted by the bootloader, or that an incompatible file "
"has been passed to the kernel.");
}
if ( strcmp(sb->magic, "sortix-initrd-1") == 0 )
{
Panic("Sortix initrd format version 1 is no longer supported.");
}
if ( strcmp(sb->magic, "sortix-initrd-2") != 0 )
{
Panic("The initrd has a format that isn't supported. Perhaps it is "
"too new? Try downgrade or regenerate the initrd.");
}
if ( size < sb->fssize )
{
PanicF("The initrd said it is %u bytes, but the kernel was only passed "
"%zu bytes by the bootloader, which is not enough.", sb->fssize,
size);
}
CheckSum();
}
static bool ExtractDir(ioctx_t* ctx, uint32_t ino, Ref<Descriptor> node);
static bool ExtractFile(ioctx_t* ctx, uint32_t ino, Ref<Descriptor> file);
static bool ExtractNode(ioctx_t* ctx, uint32_t ino, Ref<Descriptor> node);
static bool ExtractDir(ioctx_t* ctx, uint32_t ino, Ref<Descriptor> dir)
{
size_t numfiles = GetNumFiles(ino);
for ( size_t i = 0; i < numfiles; i++ )
{
const char* name = GetFilename(ino, i);
if ( !name )
return false;
if ( IsDotOrDotDot(name) )
continue;
uint32_t childino = Traverse(ino, name);
if ( !childino )
return false;
const initrd_inode_t* child = GetInode(childino);
mode_t mode = InitRDModeToHost(child->mode);
if ( INITRD_S_ISDIR(child->mode) )
{
if ( dir->mkdir(ctx, name, mode) && errno != EEXIST )
return false;
Ref<Descriptor> desc = dir->open(ctx, name, O_SEARCH | O_DIRECTORY, 0);
if ( !desc )
return false;
if ( !ExtractNode(ctx, childino, desc) )
return false;
}
if ( INITRD_S_ISREG(child->mode) )
{
Ref<Descriptor> desc = dir->open(ctx, name, O_WRITE | O_CREATE, mode);
if ( !desc )
return false;
if ( !ExtractNode(ctx, childino, desc) )
return false;
}
}
return true;
}
static bool ExtractFile(ioctx_t* ctx, uint32_t ino, Ref<Descriptor> file)
{
size_t filesize;
const uint8_t* data = Open(ino, &filesize);
if ( !data )
return false;
if ( file->truncate(ctx, filesize) != 0 )
return false;
size_t sofar = 0;
while ( sofar < filesize )
{
ssize_t numbytes = file->write(ctx, data + sofar, filesize - sofar);
if ( numbytes <= 0 )
return false;
sofar += numbytes;
}
return true;
}
static bool ExtractNode(ioctx_t* ctx, uint32_t ino, Ref<Descriptor> node)
{
const initrd_inode_t* inode = GetInode(ino);
if ( !inode )
return false;
if ( node->chmod(ctx, InitRDModeToHost(inode->mode)) < 0 )
return false;
if ( node->chown(ctx, inode->uid, inode->gid) < 0 )
return false;
if ( INITRD_S_ISDIR(inode->mode) )
if ( !ExtractDir(ctx, ino, node) )
return false;
if ( INITRD_S_ISREG(inode->mode) )
if ( !ExtractFile(ctx, ino, node) )
return false;
struct timespec ctime = timespec_make((time_t) inode->ctime, 0);
struct timespec mtime = timespec_make((time_t) inode->mtime, 0);
if ( node->utimens(ctx, &mtime, &ctime, &mtime) < 0 )
return false;
return true;
}
bool ExtractInto(Ref<Descriptor> desc)
{
ioctx_t ctx; SetupKernelIOCtx(&ctx);
return ExtractNode(&ctx, sb->root, desc);
}
bool ExtractFromPhysicalInto(addr_t physaddr, size_t size, Ref<Descriptor> desc)
{
Init(physaddr, size);
return ExtractInto(desc);
}
void Delete()
{
size_t size = initrdsize;
initrd = NULL;
initrdsize = 0;
// Unmap the pages and return the physical frames for reallocation.
addr_t mapat = initrd_addr_alloc.from;
for ( size_t i = 0; i < size; i += Page::Size() )
{
addr_t addr = Memory::Unmap(mapat + i);
Page::Put(addr);
}
Memory::Flush();
// Free the used virtual address space.
FreeKernelAddress(&initrd_addr_alloc);
}
} // namespace InitRD
} // namespace Sortix