| 1 | /*
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| 2 | * ismounted.c --- Check to see if the filesystem was mounted
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| 3 | *
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| 4 | * Copyright (C) 1995,1996,1997,1998,1999,2000 Theodore Ts'o.
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| 5 | *
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| 6 | * %Begin-Header%
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| 7 | * This file may be redistributed under the terms of the GNU Public
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| 8 | * License.
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| 9 | * %End-Header%
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| 10 | */
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| 11 |
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| 12 | #include <stdio.h>
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| 13 | #if HAVE_UNISTD_H
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| 14 | #include <unistd.h>
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| 15 | #endif
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| 16 | #if HAVE_ERRNO_H
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| 17 | #include <errno.h>
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| 18 | #endif
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| 19 | #include <fcntl.h>
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| 20 | #ifdef HAVE_LINUX_FD_H
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| 21 | #include <linux/fd.h>
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| 22 | #endif
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| 23 | #ifdef HAVE_MNTENT_H
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| 24 | #include <mntent.h>
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| 25 | #endif
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| 26 | #ifdef HAVE_GETMNTINFO
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| 27 | #include <paths.h>
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| 28 | #include <sys/param.h>
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| 29 | #include <sys/mount.h>
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| 30 | #endif /* HAVE_GETMNTINFO */
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| 31 | #include <string.h>
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| 32 | #include <sys/stat.h>
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| 33 |
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| 34 | #include "ext2_fs.h"
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| 35 | #include "ext2fs.h"
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| 36 |
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| 37 | #ifdef HAVE_MNTENT_H
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| 38 | /*
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| 39 | * Helper function which checks a file in /etc/mtab format to see if a
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| 40 | * filesystem is mounted. Returns an error if the file doesn't exist
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| 41 | * or can't be opened.
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| 42 | */
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| 43 | static errcode_t check_mntent_file(const char *mtab_file, const char *file,
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| 44 | int *mount_flags, char *mtpt, int mtlen)
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| 45 | {
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| 46 | struct mntent *mnt;
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| 47 | struct stat st_buf;
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| 48 | errcode_t retval = 0;
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| 49 | dev_t file_dev=0, file_rdev=0;
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| 50 | ino_t file_ino=0;
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| 51 | FILE *f;
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| 52 | int fd;
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| 53 |
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| 54 | *mount_flags = 0;
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| 55 | if ((f = setmntent (mtab_file, "r")) == NULL)
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| 56 | return errno;
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| 57 | if (stat(file, &st_buf) == 0) {
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| 58 | if (S_ISBLK(st_buf.st_mode)) {
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| 59 | #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
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| 60 | file_rdev = st_buf.st_rdev;
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| 61 | #endif /* __GNU__ */
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| 62 | } else {
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| 63 | file_dev = st_buf.st_dev;
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| 64 | file_ino = st_buf.st_ino;
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| 65 | }
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| 66 | }
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| 67 | while ((mnt = getmntent (f)) != NULL) {
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| 68 | if (strcmp(file, mnt->mnt_fsname) == 0)
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| 69 | break;
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| 70 | if (stat(mnt->mnt_fsname, &st_buf) == 0) {
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| 71 | if (S_ISBLK(st_buf.st_mode)) {
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| 72 | #ifndef __GNU__
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| 73 | if (file_rdev && (file_rdev == st_buf.st_rdev))
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| 74 | break;
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| 75 | #endif /* __GNU__ */
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| 76 | } else {
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| 77 | if (file_dev && ((file_dev == st_buf.st_dev) &&
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| 78 | (file_ino == st_buf.st_ino)))
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| 79 | break;
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| 80 | }
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| 81 | }
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| 82 | }
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| 83 |
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| 84 | if (mnt == 0) {
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| 85 | #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
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| 86 | /*
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| 87 | * Do an extra check to see if this is the root device. We
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| 88 | * can't trust /etc/mtab, and /proc/mounts will only list
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| 89 | * /dev/root for the root filesystem. Argh. Instead we
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| 90 | * check if the given device has the same major/minor number
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| 91 | * as the device that the root directory is on.
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| 92 | */
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| 93 | if (file_rdev && stat("/", &st_buf) == 0) {
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| 94 | if (st_buf.st_dev == file_rdev) {
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| 95 | *mount_flags = EXT2_MF_MOUNTED;
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| 96 | if (mtpt)
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| 97 | strncpy(mtpt, "/", mtlen);
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| 98 | goto is_root;
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| 99 | }
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| 100 | }
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| 101 | #endif /* __GNU__ */
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| 102 | goto errout;
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| 103 | }
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| 104 | #ifndef __GNU__ /* The GNU hurd is deficient; what else is new? */
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| 105 | /* Validate the entry in case /etc/mtab is out of date */
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| 106 | /*
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| 107 | * We need to be paranoid, because some broken distributions
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| 108 | * (read: Slackware) don't initialize /etc/mtab before checking
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| 109 | * all of the non-root filesystems on the disk.
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| 110 | */
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| 111 | if (stat(mnt->mnt_dir, &st_buf) < 0) {
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| 112 | retval = errno;
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| 113 | if (retval == ENOENT) {
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| 114 | #ifdef DEBUG
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| 115 | printf("Bogus entry in %s! (%s does not exist)\n",
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| 116 | mtab_file, mnt->mnt_dir);
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| 117 | #endif /* DEBUG */
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| 118 | retval = 0;
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| 119 | }
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| 120 | goto errout;
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| 121 | }
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| 122 | if (file_rdev && (st_buf.st_dev != file_rdev)) {
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| 123 | #ifdef DEBUG
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| 124 | printf("Bogus entry in %s! (%s not mounted on %s)\n",
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| 125 | mtab_file, file, mnt->mnt_dir);
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| 126 | #endif /* DEBUG */
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| 127 | goto errout;
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| 128 | }
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| 129 | #endif /* __GNU__ */
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| 130 | *mount_flags = EXT2_MF_MOUNTED;
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| 131 |
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| 132 | #ifdef MNTOPT_RO
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| 133 | /* Check to see if the ro option is set */
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| 134 | if (hasmntopt(mnt, MNTOPT_RO))
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| 135 | *mount_flags |= EXT2_MF_READONLY;
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| 136 | #endif
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| 137 |
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| 138 | if (mtpt)
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| 139 | strncpy(mtpt, mnt->mnt_dir, mtlen);
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| 140 | /*
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| 141 | * Check to see if we're referring to the root filesystem.
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| 142 | * If so, do a manual check to see if we can open /etc/mtab
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| 143 | * read/write, since if the root is mounted read/only, the
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| 144 | * contents of /etc/mtab may not be accurate.
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| 145 | */
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| 146 | if (!strcmp(mnt->mnt_dir, "/")) {
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| 147 | is_root:
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| 148 | #define TEST_FILE "/.ismount-test-file"
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| 149 | *mount_flags |= EXT2_MF_ISROOT;
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| 150 | fd = open(TEST_FILE, O_RDWR|O_CREAT);
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| 151 | if (fd < 0) {
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| 152 | if (errno == EROFS)
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| 153 | *mount_flags |= EXT2_MF_READONLY;
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| 154 | } else
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| 155 | close(fd);
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| 156 | (void) unlink(TEST_FILE);
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| 157 | }
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| 158 | retval = 0;
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| 159 | errout:
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| 160 | endmntent (f);
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| 161 | return retval;
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| 162 | }
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| 163 |
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| 164 | static errcode_t check_mntent(const char *file, int *mount_flags,
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| 165 | char *mtpt, int mtlen)
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| 166 | {
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| 167 | errcode_t retval;
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| 168 |
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| 169 | #ifdef DEBUG
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| 170 | retval = check_mntent_file("/tmp/mtab", file, mount_flags,
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| 171 | mtpt, mtlen);
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| 172 | if (retval == 0)
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| 173 | return 0;
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| 174 | #endif /* DEBUG */
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| 175 | #ifdef __linux__
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| 176 | retval = check_mntent_file("/proc/mounts", file, mount_flags,
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| 177 | mtpt, mtlen);
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| 178 | if (retval == 0 && (*mount_flags != 0))
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| 179 | return 0;
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| 180 | #endif /* __linux__ */
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| 181 | #if defined(MOUNTED) || defined(_PATH_MOUNTED)
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| 182 | #ifndef MOUNTED
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| 183 | #define MOUNTED _PATH_MOUNTED
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| 184 | #endif /* MOUNTED */
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| 185 | retval = check_mntent_file(MOUNTED, file, mount_flags, mtpt, mtlen);
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| 186 | return retval;
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| 187 | #else
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| 188 | *mount_flags = 0;
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| 189 | return 0;
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| 190 | #endif /* defined(MOUNTED) || defined(_PATH_MOUNTED) */
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| 191 | }
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| 192 |
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| 193 | #else
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| 194 | #if defined(HAVE_GETMNTINFO)
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| 195 |
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| 196 | static errcode_t check_getmntinfo(const char *file, int *mount_flags,
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| 197 | char *mtpt, int mtlen)
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| 198 | {
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| 199 | struct statfs *mp;
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| 200 | int len, n;
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| 201 | const char *s1;
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| 202 | char *s2;
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| 203 |
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| 204 | n = getmntinfo(&mp, MNT_NOWAIT);
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| 205 | if (n == 0)
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| 206 | return errno;
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| 207 |
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| 208 | len = sizeof(_PATH_DEV) - 1;
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| 209 | s1 = file;
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| 210 | if (strncmp(_PATH_DEV, s1, len) == 0)
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| 211 | s1 += len;
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| 212 |
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| 213 | *mount_flags = 0;
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| 214 | while (--n >= 0) {
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| 215 | s2 = mp->f_mntfromname;
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| 216 | if (strncmp(_PATH_DEV, s2, len) == 0) {
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| 217 | s2 += len - 1;
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| 218 | *s2 = 'r';
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| 219 | }
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| 220 | if (strcmp(s1, s2) == 0 || strcmp(s1, &s2[1]) == 0) {
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| 221 | *mount_flags = EXT2_MF_MOUNTED;
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| 222 | break;
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| 223 | }
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| 224 | ++mp;
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| 225 | }
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| 226 | if (mtpt)
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| 227 | strncpy(mtpt, mp->f_mntonname, mtlen);
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| 228 | return 0;
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| 229 | }
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| 230 | #endif /* HAVE_GETMNTINFO */
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| 231 | #endif /* HAVE_MNTENT_H */
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| 232 |
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| 233 | /*
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| 234 | * Check to see if we're dealing with the swap device.
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| 235 | */
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| 236 | static int is_swap_device(const char *file)
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| 237 | {
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| 238 | FILE *f;
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| 239 | char buf[1024], *cp;
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| 240 | dev_t file_dev;
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| 241 | struct stat st_buf;
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| 242 | int ret = 0;
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| 243 |
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| 244 | file_dev = 0;
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| 245 | #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
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| 246 | if ((stat(file, &st_buf) == 0) &&
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| 247 | S_ISBLK(st_buf.st_mode))
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| 248 | file_dev = st_buf.st_rdev;
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| 249 | #endif /* __GNU__ */
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| 250 |
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| 251 | if (!(f = fopen("/proc/swaps", "r")))
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| 252 | return 0;
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| 253 | /* Skip the first line */
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| 254 | fgets(buf, sizeof(buf), f);
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| 255 | while (!feof(f)) {
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| 256 | if (!fgets(buf, sizeof(buf), f))
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| 257 | break;
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| 258 | if ((cp = strchr(buf, ' ')) != NULL)
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| 259 | *cp = 0;
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| 260 | if ((cp = strchr(buf, '\t')) != NULL)
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| 261 | *cp = 0;
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| 262 | if (strcmp(buf, file) == 0) {
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| 263 | ret++;
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| 264 | break;
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| 265 | }
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| 266 | #ifndef __GNU__
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| 267 | if (file_dev && (stat(buf, &st_buf) == 0) &&
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| 268 | S_ISBLK(st_buf.st_mode) &&
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| 269 | file_dev == st_buf.st_rdev) {
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| 270 | ret++;
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| 271 | break;
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| 272 | }
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| 273 | #endif /* __GNU__ */
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| 274 | }
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| 275 | fclose(f);
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| 276 | return ret;
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| 277 | }
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| 278 |
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| 279 |
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| 280 | /*
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| 281 | * ext2fs_check_mount_point() returns 1 if the device is mounted, 0
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| 282 | * otherwise. If mtpt is non-NULL, the directory where the device is
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| 283 | * mounted is copied to where mtpt is pointing, up to mtlen
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| 284 | * characters.
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| 285 | */
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| 286 | #ifdef __TURBOC__
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| 287 | # pragma argsused
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| 288 | #endif
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| 289 | errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags,
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| 290 | char *mtpt, int mtlen)
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| 291 | {
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| 292 | if (is_swap_device(device)) {
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| 293 | *mount_flags = EXT2_MF_MOUNTED | EXT2_MF_SWAP;
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| 294 | strncpy(mtpt, "<swap>", mtlen);
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| 295 | return 0;
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| 296 | }
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| 297 | #ifdef HAVE_MNTENT_H
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| 298 | return check_mntent(device, mount_flags, mtpt, mtlen);
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| 299 | #else
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| 300 | #ifdef HAVE_GETMNTINFO
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| 301 | return check_getmntinfo(device, mount_flags, mtpt, mtlen);
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| 302 | #else
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| 303 | #ifdef __GNUC__
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| 304 | #warning "Can't use getmntent or getmntinfo to check for mounted filesystems!"
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| 305 | #endif
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| 306 | *mount_flags = 0;
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| 307 | return 0;
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| 308 | #endif /* HAVE_GETMNTINFO */
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| 309 | #endif /* HAVE_MNTENT_H */
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| 310 | }
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| 311 |
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| 312 | /*
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| 313 | * ext2fs_check_if_mounted() sets the mount_flags EXT2_MF_MOUNTED,
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| 314 | * EXT2_MF_READONLY, and EXT2_MF_ROOT
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| 315 | *
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| 316 | */
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| 317 | errcode_t ext2fs_check_if_mounted(const char *file, int *mount_flags)
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| 318 | {
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| 319 | return ext2fs_check_mount_point(file, mount_flags, NULL, 0);
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| 320 | }
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| 321 |
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| 322 | #ifdef DEBUG
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| 323 | int main(int argc, char **argv)
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| 324 | {
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| 325 | int retval, mount_flags;
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| 326 | char mntpt[80];
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| 327 |
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| 328 | if (argc < 2) {
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| 329 | fprintf(stderr, "Usage: %s device\n", argv[0]);
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| 330 | exit(1);
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| 331 | }
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| 332 |
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| 333 | mntpt[0] = 0;
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| 334 | retval = ext2fs_check_mount_point(argv[1], &mount_flags,
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| 335 | mntpt, sizeof(mntpt));
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| 336 | if (retval) {
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| 337 | com_err(argv[0], retval,
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| 338 | "while calling ext2fs_check_if_mounted");
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| 339 | exit(1);
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| 340 | }
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| 341 | printf("Device %s reports flags %02x\n", argv[1], mount_flags);
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| 342 | if (mount_flags & EXT2_MF_BUSY)
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| 343 | printf("\t%s is apparently in use.\n", argv[1]);
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| 344 | if (mount_flags & EXT2_MF_MOUNTED)
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| 345 | printf("\t%s is mounted.\n", argv[1]);
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| 346 | if (mount_flags & EXT2_MF_SWAP)
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| 347 | printf("\t%s is a swap device.\n", argv[1]);
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| 348 | if (mount_flags & EXT2_MF_READONLY)
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| 349 | printf("\t%s is read-only.\n", argv[1]);
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| 350 | if (mount_flags & EXT2_MF_ISROOT)
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| 351 | printf("\t%s is the root filesystem.\n", argv[1]);
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| 352 | if (mntpt[0])
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| 353 | printf("\t%s is mounted on %s.\n", argv[1], mntpt);
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| 354 | exit(0);
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| 355 | }
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| 356 | #endif /* DEBUG */
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