1 // SPDX-License-Identifier: CDDL-1.0 2 /* 3 * CDDL HEADER START 4 * 5 * The contents of this file are subject to the terms of the 6 * Common Development and Distribution License, Version 1.0 only 7 * (the "License"). You may not use this file except in compliance 8 * with the License. 9 * 10 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 11 * or https://opensource.org/licenses/CDDL-1.0. 12 * See the License for the specific language governing permissions 13 * and limitations under the License. 14 * 15 * When distributing Covered Code, include this CDDL HEADER in each 16 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 17 * If applicable, add the following below this CDDL HEADER, with the 18 * fields enclosed by brackets "[]" replaced with your own identifying 19 * information: Portions Copyright [yyyy] [name of copyright owner] 20 * 21 * CDDL HEADER END 22 */ 23 /* 24 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 25 * Copyright 2006 Ricardo Correia. All rights reserved. 26 * Use is subject to license terms. 27 */ 28 29 /* Copyright (c) 1988 AT&T */ 30 /* All Rights Reserved */ 31 32 #include <stdio.h> 33 #include <string.h> 34 #include <mntent.h> 35 #include <sys/errno.h> 36 #include <sys/mnttab.h> 37 38 #include <sys/types.h> 39 #include <sys/sysmacros.h> 40 #include <sys/stat.h> 41 #include <unistd.h> 42 #include <libzutil.h> 43 44 #define BUFSIZE (MNT_LINE_MAX + 2) 45 46 static __thread char buf[BUFSIZE]; 47 48 int 49 _sol_getmntent(FILE *fp, struct mnttab *mgetp) 50 { 51 struct mntent mntbuf; 52 struct mntent *ret; 53 54 ret = getmntent_r(fp, &mntbuf, buf, BUFSIZE); 55 56 if (ret != NULL) { 57 mgetp->mnt_special = mntbuf.mnt_fsname; 58 mgetp->mnt_mountp = mntbuf.mnt_dir; 59 mgetp->mnt_fstype = mntbuf.mnt_type; 60 mgetp->mnt_mntopts = mntbuf.mnt_opts; 61 return (0); 62 } 63 64 if (feof(fp)) 65 return (-1); 66 67 return (MNT_TOOLONG); 68 } 69 70 static int 71 getextmntent_impl(FILE *fp, struct mnttab *mp, uint64_t *mnt_id, dev_t *dev) 72 { 73 int ret; 74 struct stat64 st; 75 76 *mnt_id = 0; 77 ret = _sol_getmntent(fp, (struct mnttab *)mp); 78 if (ret == 0) { 79 #ifdef HAVE_STATX_MNT_ID 80 struct statx stx; 81 if (statx(AT_FDCWD, mp->mnt_mountp, 82 AT_STATX_SYNC_AS_STAT | AT_SYMLINK_NOFOLLOW, 83 STATX_MNT_ID, &stx) == 0 && (stx.stx_mask & STATX_MNT_ID)) 84 *mnt_id = stx.stx_mnt_id; 85 #endif 86 if (stat64(mp->mnt_mountp, &st) != 0) { 87 *dev = 0; 88 return (ret); 89 } 90 *dev = st.st_dev; 91 } 92 93 return (ret); 94 } 95 96 int 97 getextmntent(const char *path, struct mnttab *entry, struct stat64 *statbuf) 98 { 99 struct stat64 st; 100 FILE *fp; 101 int match; 102 boolean_t have_mnt_id = B_FALSE; 103 uint64_t target_mnt_id = 0; 104 uint64_t entry_mnt_id; 105 dev_t dev; 106 #ifdef HAVE_STATX_MNT_ID 107 struct statx stx; 108 #endif 109 110 if (strlen(path) >= MAXPATHLEN) { 111 (void) fprintf(stderr, "invalid object; pathname too long\n"); 112 return (-1); 113 } 114 115 /* 116 * Search for the path in /proc/self/mounts. Rather than looking for the 117 * specific path, which can be fooled by non-standard paths (i.e. ".." 118 * or "//"), we stat() the path and search for the corresponding 119 * (major,minor) device pair. 120 */ 121 if (stat64(path, statbuf) != 0) { 122 (void) fprintf(stderr, "cannot open '%s': %s\n", 123 path, zfs_strerror(errno)); 124 return (-1); 125 } 126 127 #ifdef HAVE_STATX_MNT_ID 128 if (statx(AT_FDCWD, path, AT_STATX_SYNC_AS_STAT | AT_SYMLINK_NOFOLLOW, 129 STATX_MNT_ID, &stx) == 0 && (stx.stx_mask & STATX_MNT_ID)) { 130 have_mnt_id = B_TRUE; 131 target_mnt_id = stx.stx_mnt_id; 132 } 133 #endif 134 135 if ((fp = fopen(MNTTAB, "re")) == NULL) { 136 (void) fprintf(stderr, "cannot open %s\n", MNTTAB); 137 return (-1); 138 } 139 140 /* 141 * Search for the given (major,minor) pair in the mount table. 142 */ 143 144 match = 0; 145 while (getextmntent_impl(fp, entry, &entry_mnt_id, &dev) == 0) { 146 if (have_mnt_id) { 147 match = (entry_mnt_id == target_mnt_id); 148 } else { 149 match = (dev == statbuf->st_dev); 150 } 151 if (match) 152 break; 153 } 154 (void) fclose(fp); 155 156 if (!match) { 157 (void) fprintf(stderr, "cannot find mountpoint for '%s'\n", 158 path); 159 return (-1); 160 } 161 162 if (stat64(entry->mnt_mountp, &st) != 0) 163 return (-1); 164 165 return (0); 166 } 167