It is now permission-oriented, not just user/kernel oriented. Added <sys/mman.h> with nice PROT_{READ,WRITE,EXEC,FORK} constants.
237 lines
6.6 KiB
C++
237 lines
6.6 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
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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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initrd.cpp
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Provides low-level access to a Sortix init ramdisk.
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*******************************************************************************/
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#include <sortix/kernel/platform.h>
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#include <sortix/kernel/memorymanagement.h>
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#include <sortix/stat.h>
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#include <sortix/mman.h>
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#include <sortix/initrd.h>
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#include <libmaxsi/error.h>
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#include <libmaxsi/memory.h>
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#include <libmaxsi/string.h>
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#include <libmaxsi/crc32.h>
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#include "initrd.h"
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#include "syscall.h"
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using namespace Maxsi;
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namespace Sortix {
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namespace InitRD {
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uint8_t* initrd;
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size_t initrdsize;
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const initrd_superblock_t* sb;
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static uint32_t HostModeToInitRD(mode_t mode)
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{
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uint32_t result = mode & 0777; // Lower 9 bits per POSIX and tradition.
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if ( S_ISVTX & mode ) { result |= INITRD_S_ISVTX; }
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if ( S_ISSOCK(mode) ) { result |= INITRD_S_IFSOCK; }
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if ( S_ISLNK(mode) ) { result |= INITRD_S_IFLNK; }
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if ( S_ISREG(mode) ) { result |= INITRD_S_IFREG; }
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if ( S_ISBLK(mode) ) { result |= INITRD_S_IFBLK; }
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if ( S_ISDIR(mode) ) { result |= INITRD_S_IFDIR; }
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if ( S_ISCHR(mode) ) { result |= INITRD_S_IFCHR; }
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if ( S_ISFIFO(mode) ) { result |= INITRD_S_IFIFO; }
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return result;
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}
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static mode_t InitRDModeToHost(uint32_t mode)
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{
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mode_t result = mode & 0777; // Lower 9 bits per POSIX and tradition.
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if ( INITRD_S_ISVTX & mode ) { result |= S_ISVTX; }
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if ( INITRD_S_ISSOCK(mode) ) { result |= S_IFSOCK; }
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if ( INITRD_S_ISLNK(mode) ) { result |= S_IFLNK; }
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if ( INITRD_S_ISREG(mode) ) { result |= S_IFREG; }
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if ( INITRD_S_ISBLK(mode) ) { result |= S_IFBLK; }
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if ( INITRD_S_ISDIR(mode) ) { result |= S_IFDIR; }
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if ( INITRD_S_ISCHR(mode) ) { result |= S_IFCHR; }
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if ( INITRD_S_ISFIFO(mode) ) { result |= S_IFIFO; }
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return result;
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}
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uint32_t Root()
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{
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return sb->root;
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}
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static const initrd_inode_t* GetInode(uint32_t inode)
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{
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if ( sb->inodecount <= inode ) { Error::Set(EINVAL); return NULL; }
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uint32_t pos = sb->inodeoffset + sb->inodesize * inode;
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return (const initrd_inode_t*) (initrd + pos);
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}
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bool Stat(uint32_t ino, struct stat* st)
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{
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const initrd_inode_t* inode = GetInode(ino);
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if ( !inode ) { return false; }
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st->st_ino = ino;
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st->st_mode = HostModeToInitRD(inode->mode);
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st->st_nlink = inode->nlink;
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st->st_uid = inode->uid;
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st->st_gid = inode->gid;
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st->st_size = inode->size;
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st->st_atime = inode->mtime;
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st->st_ctime = inode->ctime;
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st->st_mtime = inode->mtime;
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st->st_blksize = 1;
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st->st_blocks = inode->size;
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return true;
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}
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uint8_t* Open(uint32_t ino, size_t* size)
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{
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const initrd_inode_t* inode = GetInode(ino);
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if ( !inode ) { return NULL; }
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*size = inode->size;
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return initrd + inode->dataoffset;
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}
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uint32_t Traverse(uint32_t ino, const char* name)
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{
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const initrd_inode_t* inode = GetInode(ino);
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if ( !inode ) { return 0; }
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if ( !INITRD_S_ISDIR(inode->mode) ) { Error::Set(ENOTDIR); return 0; }
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uint32_t offset = 0;
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while ( offset < inode->size )
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{
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uint32_t pos = inode->dataoffset + offset;
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const initrd_dirent* dirent = (const initrd_dirent*) (initrd + pos);
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if ( dirent->namelen && !String::Compare(dirent->name, name) )
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{
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return dirent->inode;
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}
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offset += dirent->reclen;
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}
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Error::Set(ENOENT);
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return 0;
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}
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const char* GetFilename(uint32_t dir, size_t index)
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{
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const initrd_inode_t* inode = GetInode(dir);
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if ( !inode ) { return 0; }
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if ( !INITRD_S_ISDIR(inode->mode) ) { Error::Set(ENOTDIR); return 0; }
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uint32_t offset = 0;
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while ( offset < inode->size )
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{
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uint32_t pos = inode->dataoffset + offset;
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const initrd_dirent* dirent = (const initrd_dirent*) (initrd + pos);
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if ( index-- == 0 ) { return dirent->name; }
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offset += dirent->reclen;
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}
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Error::Set(EINVAL);
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return NULL;
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}
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size_t GetNumFiles(uint32_t dir)
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{
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const initrd_inode_t* inode = GetInode(dir);
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if ( !inode ) { return 0; }
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if ( !INITRD_S_ISDIR(inode->mode) ) { Error::Set(ENOTDIR); return 0; }
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uint32_t offset = 0;
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size_t numentries = 0;
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while ( offset < inode->size )
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{
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uint32_t pos = inode->dataoffset + offset;
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const initrd_dirent* dirent = (const initrd_dirent*) (initrd + pos);
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numentries++;
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offset += dirent->reclen;
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}
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return numentries;
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}
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void CheckSum()
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{
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uint32_t amount = sb->fssize - sb->sumsize;
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uint8_t* filesum = initrd + amount;
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if ( sb->sumalgorithm != INITRD_ALGO_CRC32 )
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{
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Log::PrintF("Warning: InitRD checksum algorithm not supported\n");
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return;
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}
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uint32_t crc32 = *((uint32_t*) filesum);
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uint32_t filecrc32 = CRC32::Hash(initrd, amount);
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if ( crc32 != filecrc32 )
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{
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PanicF("InitRD had checksum %X, expected %X: this means the ramdisk "
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"may have been corrupted by the bootloader.", filecrc32, crc32);
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}
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}
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void Init(addr_t phys, size_t size)
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{
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// First up, map the initrd onto the kernel's address space.
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addr_t virt = Memory::GetInitRD();
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size_t amount = 0;
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while ( amount < size )
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{
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if ( !Memory::Map(phys + amount, virt + amount, PROT_KREAD) )
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{
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Panic("Unable to map the init ramdisk into virtual memory");
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}
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amount += 0x1000UL;
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}
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Memory::Flush();
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initrd = (uint8_t*) virt;
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initrdsize = size;
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if ( size < sizeof(*sb) ) { PanicF("initrd is too small"); }
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sb = (const initrd_superblock_t*) initrd;
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if ( !String::StartsWith(sb->magic, "sortix-initrd") )
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{
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Panic("Invalid magic value in initrd. This means the ramdisk may have "
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"been corrupted by the bootloader, or that an incompatible file "
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"has been passed to the kernel.");
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}
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if ( String::Compare(sb->magic, "sortix-initrd-1") == 0 )
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{
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Panic("Sortix initrd format version 1 is no longer supported.");
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}
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if ( String::Compare(sb->magic, "sortix-initrd-2") != 0 )
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{
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Panic("The initrd has a format that isn't supported. Perhaps it is "
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"too new? Try downgrade or regenerate the initrd.");
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}
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if ( size < sb->fssize )
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{
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PanicF("The initrd said it is %u bytes, but the kernel was only passed "
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"%zu bytes by the bootloader, which is not enough.", sb->fssize,
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size);
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}
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CheckSum();
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}
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} // namespace InitRD
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} // namespace Sortix
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