466 lines
11 KiB
C
466 lines
11 KiB
C
/*
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* ismounted.c --- Check to see if the filesystem was mounted
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*
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* Copyright (C) 1995,1996,1997,1998,1999,2000 Theodore Ts'o.
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Library
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* General Public License, version 2.
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* %End-Header%
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*/
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/* define BSD_SOURCE to make sure we get the major() macro */
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#ifndef _BSD_SOURCE
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#define _BSD_SOURCE
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#endif
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#ifndef _DEFAULT_SOURCE
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#define _DEFAULT_SOURCE /* since glibc 2.20 _SVID_SOURCE is deprecated */
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#endif
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#include "config.h"
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#include <stdio.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#if HAVE_ERRNO_H
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#include <errno.h>
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#endif
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#include <fcntl.h>
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#ifdef HAVE_LINUX_FD_H
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#include <linux/fd.h>
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#endif
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#ifdef HAVE_LINUX_LOOP_H
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#include <linux/loop.h>
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#include <sys/ioctl.h>
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#ifdef HAVE_LINUX_MAJOR_H
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#include <linux/major.h>
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#endif /* HAVE_LINUX_MAJOR_H */
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#endif /* HAVE_LINUX_LOOP_H */
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#ifdef HAVE_MNTENT_H
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#include <mntent.h>
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#endif
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#ifdef HAVE_GETMNTINFO
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#include <paths.h>
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#include <sys/param.h>
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#include <sys/mount.h>
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#endif /* HAVE_GETMNTINFO */
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#include <string.h>
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#include <sys/stat.h>
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#if HAVE_SYS_TYPES_H
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#include <sys/types.h>
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#endif
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#ifdef HAVE_SYS_SYSMACROS_H
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#include <sys/sysmacros.h>
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#endif
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#include "ext2_fs.h"
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#include "ext2fs.h"
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#include "ext2fsP.h"
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#ifdef HAVE_SETMNTENT
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/*
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* Check to see if a regular file is mounted.
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* If /etc/mtab/ is a symlink of /proc/mounts, you will need the following check
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* because the name in /proc/mounts is a loopback device not a regular file.
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*/
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static int check_loop_mounted(const char *mnt_fsname, dev_t mnt_rdev,
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dev_t file_dev, ino_t file_ino)
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{
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#if defined(HAVE_LINUX_LOOP_H) && defined(HAVE_LINUX_MAJOR_H)
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struct loop_info64 loopinfo = {0, };
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int loop_fd, ret;
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if (major(mnt_rdev) == LOOP_MAJOR) {
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loop_fd = open(mnt_fsname, O_RDONLY);
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if (loop_fd < 0)
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return -1;
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ret = ioctl(loop_fd, LOOP_GET_STATUS64, &loopinfo);
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close(loop_fd);
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if (ret < 0)
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return -1;
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if (file_dev == loopinfo.lo_device &&
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file_ino == loopinfo.lo_inode)
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return 1;
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}
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#endif /* defined(HAVE_LINUX_LOOP_H) && defined(HAVE_LINUX_MAJOR_H) */
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return 0;
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}
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/*
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* Helper function which checks a file in /etc/mtab format to see if a
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* filesystem is mounted. Returns an error if the file doesn't exist
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* or can't be opened.
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*/
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static errcode_t check_mntent_file(const char *mtab_file, const char *file,
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int *mount_flags, char *mtpt, int mtlen)
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{
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struct mntent *mnt;
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struct stat st_buf;
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errcode_t retval = 0;
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dev_t file_dev=0, file_rdev=0;
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ino_t file_ino=0;
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FILE *f;
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int fd;
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*mount_flags = 0;
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if ((f = setmntent (mtab_file, "r")) == NULL) {
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if (errno == ENOENT) {
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if (getenv("EXT2FS_NO_MTAB_OK"))
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return 0;
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else
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return EXT2_ET_NO_MTAB_FILE;
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}
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return errno;
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}
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if (stat(file, &st_buf) == 0) {
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if (ext2fsP_is_disk_device(st_buf.st_mode)) {
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#ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
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file_rdev = st_buf.st_rdev;
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#endif /* __GNU__ */
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} else {
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file_dev = st_buf.st_dev;
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file_ino = st_buf.st_ino;
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}
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}
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while ((mnt = getmntent (f)) != NULL) {
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if (mnt->mnt_fsname[0] != '/')
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continue;
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if (strcmp(file, mnt->mnt_fsname) == 0) {
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if (stat(mnt->mnt_dir, &st_buf) != 0)
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continue;
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if (file_rdev && (file_rdev != st_buf.st_dev)) {
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#ifdef DEBUG
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printf("Bogus entry in %s! "
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"(%s is not mounted on %s)\n",
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mtab_file, file, mnt->mnt_dir);
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#endif /* DEBUG */
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continue;
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}
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break;
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}
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if (stat(mnt->mnt_fsname, &st_buf) == 0) {
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if (ext2fsP_is_disk_device(st_buf.st_mode)) {
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#ifndef __GNU__
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if (file_rdev && (file_rdev == st_buf.st_rdev))
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break;
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if (check_loop_mounted(mnt->mnt_fsname,
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st_buf.st_rdev, file_dev,
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file_ino) == 1)
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break;
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#endif /* __GNU__ */
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} else {
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if (file_dev && ((file_dev == st_buf.st_dev) &&
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(file_ino == st_buf.st_ino)))
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break;
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}
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}
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}
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if (mnt == 0) {
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#ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
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/*
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* Do an extra check to see if this is the root device. We
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* can't trust /etc/mtab, and /proc/mounts will only list
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* /dev/root for the root filesystem. Argh. Instead we
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* check if the given device has the same major/minor number
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* as the device that the root directory is on.
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*/
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if (file_rdev && stat("/", &st_buf) == 0) {
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if (st_buf.st_dev == file_rdev) {
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*mount_flags = EXT2_MF_MOUNTED;
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if (mtpt)
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strncpy(mtpt, "/", mtlen);
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goto is_root;
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}
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}
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#endif /* __GNU__ */
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goto errout;
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}
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*mount_flags = EXT2_MF_MOUNTED;
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#ifdef MNTOPT_RO
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/* Check to see if the ro option is set */
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if (hasmntopt(mnt, MNTOPT_RO))
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*mount_flags |= EXT2_MF_READONLY;
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#endif
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if (mtpt)
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strncpy(mtpt, mnt->mnt_dir, mtlen);
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/*
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* Check to see if we're referring to the root filesystem.
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* If so, do a manual check to see if we can open /etc/mtab
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* read/write, since if the root is mounted read/only, the
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* contents of /etc/mtab may not be accurate.
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*/
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if (!strcmp(mnt->mnt_dir, "/")) {
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is_root:
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#define TEST_FILE "/.ismount-test-file"
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*mount_flags |= EXT2_MF_ISROOT;
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fd = open(TEST_FILE, O_RDWR|O_CREAT, 0600);
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if (fd < 0) {
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if (errno == EROFS)
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*mount_flags |= EXT2_MF_READONLY;
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} else
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close(fd);
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(void) unlink(TEST_FILE);
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}
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retval = 0;
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errout:
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endmntent (f);
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return retval;
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}
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static errcode_t check_mntent(const char *file, int *mount_flags,
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char *mtpt, int mtlen)
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{
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errcode_t retval;
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#ifdef DEBUG
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retval = check_mntent_file("/tmp/mtab", file, mount_flags,
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mtpt, mtlen);
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if (retval == 0)
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return 0;
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#endif /* DEBUG */
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#ifdef __linux__
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retval = check_mntent_file("/proc/mounts", file, mount_flags,
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mtpt, mtlen);
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if (retval == 0)
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return 0;
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#endif /* __linux__ */
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#if defined(MOUNTED) || defined(_PATH_MOUNTED)
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#ifndef MOUNTED
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#define MOUNTED _PATH_MOUNTED
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#endif /* MOUNTED */
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retval = check_mntent_file(MOUNTED, file, mount_flags, mtpt, mtlen);
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return retval;
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#else
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*mount_flags = 0;
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return 0;
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#endif /* defined(MOUNTED) || defined(_PATH_MOUNTED) */
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}
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#else
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#if defined(HAVE_GETMNTINFO)
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static errcode_t check_getmntinfo(const char *file, int *mount_flags,
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char *mtpt, int mtlen)
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{
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struct statfs *mp;
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int len, n;
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const char *s1;
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char *s2;
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n = getmntinfo(&mp, MNT_NOWAIT);
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if (n == 0)
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return errno;
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len = sizeof(_PATH_DEV) - 1;
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s1 = file;
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if (strncmp(_PATH_DEV, s1, len) == 0)
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s1 += len;
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*mount_flags = 0;
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while (--n >= 0) {
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s2 = mp->f_mntfromname;
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if (strncmp(_PATH_DEV, s2, len) == 0) {
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s2 += len - 1;
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*s2 = 'r';
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}
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if (strcmp(s1, s2) == 0 || strcmp(s1, &s2[1]) == 0) {
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*mount_flags = EXT2_MF_MOUNTED;
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break;
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}
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++mp;
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}
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if (mtpt)
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strncpy(mtpt, mp->f_mntonname, mtlen);
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return 0;
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}
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#endif /* HAVE_GETMNTINFO */
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#endif /* HAVE_SETMNTENT */
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/*
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* Check to see if we're dealing with the swap device.
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*/
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static int is_swap_device(const char *file)
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{
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FILE *f;
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char buf[1024], *cp;
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dev_t file_dev;
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struct stat st_buf;
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int ret = 0;
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file_dev = 0;
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#ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
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if ((stat(file, &st_buf) == 0) &&
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ext2fsP_is_disk_device(st_buf.st_mode))
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file_dev = st_buf.st_rdev;
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#endif /* __GNU__ */
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if (!(f = fopen("/proc/swaps", "r")))
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return 0;
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/* Skip the first line */
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if (!fgets(buf, sizeof(buf), f))
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goto leave;
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if (*buf && strncmp(buf, "Filename\t", 9))
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/* Linux <=2.6.19 contained a bug in the /proc/swaps
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* code where the header would not be displayed
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*/
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goto valid_first_line;
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while (fgets(buf, sizeof(buf), f)) {
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valid_first_line:
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if ((cp = strchr(buf, ' ')) != NULL)
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*cp = 0;
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if ((cp = strchr(buf, '\t')) != NULL)
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*cp = 0;
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if (strcmp(buf, file) == 0) {
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ret++;
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break;
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}
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#ifndef __GNU__
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if (file_dev && (stat(buf, &st_buf) == 0) &&
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ext2fsP_is_disk_device(st_buf.st_mode) &&
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file_dev == st_buf.st_rdev) {
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ret++;
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break;
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}
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#endif /* __GNU__ */
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}
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leave:
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fclose(f);
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return ret;
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}
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/*
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* ext2fs_check_mount_point() fills determines if the device is
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* mounted or otherwise busy, and fills in mount_flags with one or
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* more of the following flags: EXT2_MF_MOUNTED, EXT2_MF_ISROOT,
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* EXT2_MF_READONLY, EXT2_MF_SWAP, and EXT2_MF_BUSY. If mtpt is
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* non-NULL, the directory where the device is mounted is copied to
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* where mtpt is pointing, up to mtlen characters.
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*/
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#ifdef __TURBOC__
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#pragma argsused
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#endif
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errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags,
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char *mtpt, int mtlen)
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{
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errcode_t retval = 0;
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int busy = 0;
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if (getenv("EXT2FS_PRETEND_RO_MOUNT")) {
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*mount_flags = EXT2_MF_MOUNTED | EXT2_MF_READONLY;
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if (getenv("EXT2FS_PRETEND_ROOTFS"))
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*mount_flags = EXT2_MF_ISROOT;
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return 0;
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}
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if (getenv("EXT2FS_PRETEND_RW_MOUNT")) {
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*mount_flags = EXT2_MF_MOUNTED;
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if (getenv("EXT2FS_PRETEND_ROOTFS"))
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*mount_flags = EXT2_MF_ISROOT;
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return 0;
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}
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#ifdef __linux__ /* This only works on Linux 2.6+ systems */
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{
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struct stat st_buf;
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if (stat(device, &st_buf) == 0 &&
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ext2fsP_is_disk_device(st_buf.st_mode)) {
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int fd = open(device, O_RDONLY | O_EXCL);
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if (fd >= 0) {
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/*
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* The device is not busy so it's
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* definitelly not mounted. No need to
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* to perform any more checks.
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*/
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close(fd);
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*mount_flags = 0;
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return 0;
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} else if (errno == EBUSY) {
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busy = 1;
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}
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}
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}
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#endif
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if (is_swap_device(device)) {
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*mount_flags = EXT2_MF_MOUNTED | EXT2_MF_SWAP;
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strncpy(mtpt, "<swap>", mtlen);
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} else {
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#ifdef HAVE_SETMNTENT
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retval = check_mntent(device, mount_flags, mtpt, mtlen);
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#else
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#ifdef HAVE_GETMNTINFO
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retval = check_getmntinfo(device, mount_flags, mtpt, mtlen);
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#else
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#ifdef __GNUC__
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#warning "Can't use getmntent or getmntinfo to check for mounted filesystems!"
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#endif
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*mount_flags = 0;
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#endif /* HAVE_GETMNTINFO */
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#endif /* HAVE_SETMNTENT */
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}
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if (retval)
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return retval;
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if (busy)
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*mount_flags |= EXT2_MF_BUSY;
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return 0;
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}
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/*
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* ext2fs_check_if_mounted() sets the mount_flags EXT2_MF_MOUNTED,
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* EXT2_MF_READONLY, and EXT2_MF_ROOT
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*
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*/
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errcode_t ext2fs_check_if_mounted(const char *file, int *mount_flags)
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{
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return ext2fs_check_mount_point(file, mount_flags, NULL, 0);
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}
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#ifdef DEBUG
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int main(int argc, char **argv)
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{
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int retval, mount_flags;
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char mntpt[80];
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if (argc < 2) {
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fprintf(stderr, "Usage: %s device\n", argv[0]);
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exit(1);
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}
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add_error_table(&et_ext2_error_table);
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mntpt[0] = 0;
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retval = ext2fs_check_mount_point(argv[1], &mount_flags,
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mntpt, sizeof(mntpt));
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if (retval) {
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com_err(argv[0], retval,
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"while calling ext2fs_check_if_mounted");
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exit(1);
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}
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printf("Device %s reports flags %02x\n", argv[1], mount_flags);
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if (mount_flags & EXT2_MF_BUSY)
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printf("\t%s is apparently in use.\n", argv[1]);
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if (mount_flags & EXT2_MF_MOUNTED)
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printf("\t%s is mounted.\n", argv[1]);
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if (mount_flags & EXT2_MF_SWAP)
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printf("\t%s is a swap device.\n", argv[1]);
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if (mount_flags & EXT2_MF_READONLY)
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printf("\t%s is read-only.\n", argv[1]);
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if (mount_flags & EXT2_MF_ISROOT)
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printf("\t%s is the root filesystem.\n", argv[1]);
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if (mntpt[0])
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printf("\t%s is mounted on %s.\n", argv[1], mntpt);
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exit(0);
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}
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#endif /* DEBUG */
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