1 /* $NetBSD: readufs_ffs.c,v 1.12 2009/03/18 10:22:38 cegger Exp $ */ 2 /* from Id: readufs_ffs.c,v 1.6 2003/04/08 09:19:32 itohy Exp */ 3 4 /* 5 * FS specific support for 4.2BSD Fast Filesystem 6 * 7 * Written in 1999, 2002, 2003 by ITOH Yasufumi (itohy@NetBSD.org). 8 * Public domain. 9 * 10 * Intended to be used for boot programs (first stage). 11 * DON'T ADD ANY FANCY FEATURE. THIS SHALL BE COMPACT. 12 */ 13 14 #include "readufs.h" 15 16 #include <ufs/ffs/fs.h> 17 18 static int get_ffs_inode(ino32_t ino, union ufs_dinode *dibuf); 19 20 #define fsi (*ufsinfo) 21 #define fsi_ffs fsi.fs_u.u_ffs 22 23 /* 24 * Read and check superblock. 25 * If it is an FFS, save information from the superblock. 26 */ 27 int 28 try_ffs(void) 29 { 30 union { 31 struct fs sblk; 32 unsigned char pad[SBLOCKSIZE]; 33 } buf; 34 struct ufs_info *ufsinfo = &ufs_info; 35 static const int sblocs[] = SBLOCKSEARCH; 36 const int *sbl; 37 int magic; 38 39 #ifdef DEBUG_WITH_STDIO 40 printf("trying FFS\n"); 41 #endif 42 /* read FFS superblock */ 43 for (sbl = sblocs; ; sbl++) { 44 if (*sbl == -1) 45 return 1; 46 47 RAW_READ(&buf, (daddr_t) btodb(*sbl), SBLOCKSIZE); 48 49 magic = buf.sblk.fs_magic; 50 #ifdef DEBUG_WITH_STDIO 51 printf("FFS: sblk: pos %d magic 0x%x\n", btodb(*sbl), magic); 52 #endif 53 #ifdef USE_UFS1 54 if (magic == FS_UFS1_MAGIC 55 && !(buf.sblk.fs_old_flags & FS_FLAGS_UPDATED)) { 56 if (*sbl == SBLOCK_UFS2) 57 /* might be an alternate suberblock */ 58 continue; 59 break; 60 } 61 #endif 62 if (*sbl != buf.sblk.fs_sblockloc) 63 /* must be an alternate suberblock */ 64 continue; 65 66 #ifdef USE_UFS1 67 if (magic == FS_UFS1_MAGIC) { 68 break; 69 } 70 #endif 71 #ifdef USE_UFS2 72 if (magic == FS_UFS2_MAGIC) { 73 #ifdef USE_UFS1 74 fsi.ufstype = UFSTYPE_UFS2; 75 #endif 76 break; 77 } 78 #endif 79 } 80 81 /* 82 * XXX <ufs/ffs/fs.h> always uses fs_magic 83 * (UFS1 only or UFS2 only is impossible) 84 */ 85 fsi_ffs.magic = magic; 86 #ifdef DEBUG_WITH_STDIO 87 printf("FFS: detected UFS%d format\n", (magic == FS_UFS2_MAGIC) + 1); 88 #endif 89 90 /* This partition looks like an FFS. */ 91 fsi.fstype = UFSTYPE_FFS; 92 fsi.get_inode = get_ffs_inode; 93 94 /* Get information from the superblock. */ 95 fsi.bsize = buf.sblk.fs_bsize; 96 fsi.fsbtodb = buf.sblk.fs_fsbtodb; 97 fsi.nindir = buf.sblk.fs_nindir; 98 99 fsi_ffs.iblkno = buf.sblk.fs_iblkno; 100 fsi_ffs.old_cgoffset = buf.sblk.fs_old_cgoffset; 101 fsi_ffs.old_cgmask = buf.sblk.fs_old_cgmask; 102 fsi_ffs.fragshift = buf.sblk.fs_fragshift; 103 fsi_ffs.inopb = buf.sblk.fs_inopb; 104 fsi_ffs.ipg = buf.sblk.fs_ipg; 105 fsi_ffs.fpg = buf.sblk.fs_fpg; 106 107 return 0; 108 } 109 110 /* for inode macros */ 111 #define fs_ipg fs_u.u_ffs.ipg 112 #define fs_iblkno fs_u.u_ffs.iblkno 113 #define fs_old_cgoffset fs_u.u_ffs.old_cgoffset 114 #define fs_old_cgmask fs_u.u_ffs.old_cgmask 115 #define fs_fpg fs_u.u_ffs.fpg 116 #define fs_magic fs_u.u_ffs.magic 117 #define fs_inopb fs_u.u_ffs.inopb 118 #define fs_fragshift fs_u.u_ffs.fragshift 119 #define fs_fsbtodb fsbtodb 120 121 /* 122 * Get inode from disk. 123 */ 124 static int 125 get_ffs_inode(ino32_t ino, union ufs_dinode *dibuf) 126 { 127 struct ufs_info *ufsinfo = &ufs_info; 128 union ufs_dinode *buf = alloca((size_t) fsi.bsize); 129 union ufs_dinode *di; 130 unsigned ioff; 131 132 RAW_READ(buf, fsbtodb(&fsi, ino_to_fsba(&fsi, ino)), 133 (size_t) fsi.bsize); 134 135 ioff = ino_to_fsbo(&fsi, ino); 136 137 #if defined(USE_UFS1) && defined(USE_UFS2) 138 if (ufsinfo->ufstype == UFSTYPE_UFS1) 139 di = (void *) &(&buf->di1)[ioff]; 140 else { 141 di = (void *) &(&buf->di2)[ioff]; 142 143 /* XXX for DI_SIZE() macro */ 144 di->di1.di_size = di->di2.di_size; 145 } 146 #else 147 di = &buf[ioff]; 148 #endif 149 150 #ifdef DEBUG_WITH_STDIO 151 printf("FFS: dinode(%d): mode 0%o, nlink %d, size %u\n", 152 ino, di->di_common.di_mode, di->di_common.di_nlink, 153 (unsigned) DI_SIZE(di)); 154 #endif 155 156 if (di->di_common.di_mode == 0) 157 return 1; /* unused inode (file is not found) */ 158 159 *dibuf = *di; 160 161 return 0; 162 } 163