1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2005 Stanislav Sedov 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/malloc.h> 34 35 #include <geom/geom.h> 36 #include <geom/geom_dbg.h> 37 #include <geom/label/g_label.h> 38 39 #define EXT2FS_SB_OFFSET 1024 40 #define EXT2_SUPER_MAGIC 0xef53 41 #define EXT2_DYNAMIC_REV 1 42 43 typedef struct e2sb { 44 uint8_t fake1[56]; 45 uint16_t s_magic; 46 uint8_t fake2[18]; 47 uint32_t s_rev_level; 48 uint8_t fake3[40]; 49 char s_volume_name[16]; 50 } e2sb_t; 51 52 static void 53 g_label_ext2fs_taste(struct g_consumer *cp, char *label, size_t size) 54 { 55 struct g_provider *pp; 56 e2sb_t *fs; 57 char *s_volume_name; 58 59 g_topology_assert_not(); 60 pp = cp->provider; 61 label[0] = '\0'; 62 63 KASSERT(pp->sectorsize != 0, ("Tasting a disk with 0 sectorsize")); 64 if (pp->sectorsize < sizeof(*fs)) 65 return; 66 if ((EXT2FS_SB_OFFSET % pp->sectorsize) != 0) 67 return; 68 69 fs = g_read_data(cp, EXT2FS_SB_OFFSET, pp->sectorsize, NULL); 70 if (fs == NULL) 71 return; 72 73 /* Check for magic and versio n*/ 74 if (fs->s_magic == EXT2_SUPER_MAGIC && 75 fs->s_rev_level == EXT2_DYNAMIC_REV) { 76 G_LABEL_DEBUG(1, "ext2fs file system detected on %s.", 77 pp->name); 78 } else { 79 goto exit_free; 80 } 81 82 s_volume_name = fs->s_volume_name; 83 /* Terminate label */ 84 s_volume_name[sizeof(fs->s_volume_name) - 1] = '\0'; 85 86 if (s_volume_name[0] == '/') 87 s_volume_name += 1; 88 89 /* Check for volume label */ 90 if (s_volume_name[0] == '\0') 91 goto exit_free; 92 93 strlcpy(label, s_volume_name, size); 94 95 exit_free: 96 g_free(fs); 97 } 98 99 struct g_label_desc g_label_ext2fs = { 100 .ld_taste = g_label_ext2fs_taste, 101 .ld_dirprefix = "ext2fs/", 102 .ld_enabled = 1 103 }; 104 105 G_LABEL_INIT(ext2fs, g_label_ext2fs, "Create device nodes for EXT2FS volumes"); 106