| /* vi: set sw=4 ts=4: */ |
| /* |
| * ismounted.c --- Check to see if the filesystem was mounted |
| * |
| * Copyright (C) 1995,1996,1997,1998,1999,2000 Theodore Ts'o. |
| * |
| * %Begin-Header% |
| * This file may be redistributed under the terms of the GNU Public |
| * License. |
| * %End-Header% |
| */ |
| |
| #include <stdio.h> |
| #if HAVE_UNISTD_H |
| #include <unistd.h> |
| #endif |
| #if HAVE_ERRNO_H |
| #include <errno.h> |
| #endif |
| #include <fcntl.h> |
| #ifdef HAVE_LINUX_FD_H |
| #include <linux/fd.h> |
| #endif |
| #ifdef HAVE_MNTENT_H |
| #include <mntent.h> |
| #endif |
| #ifdef HAVE_GETMNTINFO |
| #include <paths.h> |
| #include <sys/param.h> |
| #include <sys/mount.h> |
| #endif /* HAVE_GETMNTINFO */ |
| #include <string.h> |
| #include <sys/stat.h> |
| |
| #include "ext2_fs.h" |
| #include "ext2fs.h" |
| |
| #ifdef HAVE_MNTENT_H |
| /* |
| * Helper function which checks a file in /etc/mtab format to see if a |
| * filesystem is mounted. Returns an error if the file doesn't exist |
| * or can't be opened. |
| */ |
| static errcode_t check_mntent_file(const char *mtab_file, const char *file, |
| int *mount_flags, char *mtpt, int mtlen) |
| { |
| struct mntent *mnt; |
| struct stat st_buf; |
| errcode_t retval = 0; |
| dev_t file_dev=0, file_rdev=0; |
| ino_t file_ino=0; |
| FILE *f; |
| int fd; |
| |
| *mount_flags = 0; |
| if ((f = setmntent (mtab_file, "r")) == NULL) |
| return errno; |
| if (stat(file, &st_buf) == 0) { |
| if (S_ISBLK(st_buf.st_mode)) { |
| #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ |
| file_rdev = st_buf.st_rdev; |
| #endif /* __GNU__ */ |
| } else { |
| file_dev = st_buf.st_dev; |
| file_ino = st_buf.st_ino; |
| } |
| } |
| while ((mnt = getmntent (f)) != NULL) { |
| if (strcmp(file, mnt->mnt_fsname) == 0) |
| break; |
| if (stat(mnt->mnt_fsname, &st_buf) == 0) { |
| if (S_ISBLK(st_buf.st_mode)) { |
| #ifndef __GNU__ |
| if (file_rdev && (file_rdev == st_buf.st_rdev)) |
| break; |
| #endif /* __GNU__ */ |
| } else { |
| if (file_dev && ((file_dev == st_buf.st_dev) && |
| (file_ino == st_buf.st_ino))) |
| break; |
| } |
| } |
| } |
| |
| if (mnt == 0) { |
| #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ |
| /* |
| * Do an extra check to see if this is the root device. We |
| * can't trust /etc/mtab, and /proc/mounts will only list |
| * /dev/root for the root filesystem. Argh. Instead we |
| * check if the given device has the same major/minor number |
| * as the device that the root directory is on. |
| */ |
| if (file_rdev && stat("/", &st_buf) == 0) { |
| if (st_buf.st_dev == file_rdev) { |
| *mount_flags = EXT2_MF_MOUNTED; |
| if (mtpt) |
| strncpy(mtpt, "/", mtlen); |
| goto is_root; |
| } |
| } |
| #endif /* __GNU__ */ |
| goto errout; |
| } |
| #ifndef __GNU__ /* The GNU hurd is deficient; what else is new? */ |
| /* Validate the entry in case /etc/mtab is out of date */ |
| /* |
| * We need to be paranoid, because some broken distributions |
| * (read: Slackware) don't initialize /etc/mtab before checking |
| * all of the non-root filesystems on the disk. |
| */ |
| if (stat(mnt->mnt_dir, &st_buf) < 0) { |
| retval = errno; |
| if (retval == ENOENT) { |
| #ifdef DEBUG |
| printf("Bogus entry in %s! (%s does not exist)\n", |
| mtab_file, mnt->mnt_dir); |
| #endif /* DEBUG */ |
| retval = 0; |
| } |
| goto errout; |
| } |
| if (file_rdev && (st_buf.st_dev != file_rdev)) { |
| #ifdef DEBUG |
| printf("Bogus entry in %s! (%s not mounted on %s)\n", |
| mtab_file, file, mnt->mnt_dir); |
| #endif /* DEBUG */ |
| goto errout; |
| } |
| #endif /* __GNU__ */ |
| *mount_flags = EXT2_MF_MOUNTED; |
| |
| #ifdef MNTOPT_RO |
| /* Check to see if the ro option is set */ |
| if (hasmntopt(mnt, MNTOPT_RO)) |
| *mount_flags |= EXT2_MF_READONLY; |
| #endif |
| |
| if (mtpt) |
| strncpy(mtpt, mnt->mnt_dir, mtlen); |
| /* |
| * Check to see if we're referring to the root filesystem. |
| * If so, do a manual check to see if we can open /etc/mtab |
| * read/write, since if the root is mounted read/only, the |
| * contents of /etc/mtab may not be accurate. |
| */ |
| if (LONE_CHAR(mnt->mnt_dir, '/')) { |
| is_root: |
| #define TEST_FILE "/.ismount-test-file" |
| *mount_flags |= EXT2_MF_ISROOT; |
| fd = open(TEST_FILE, O_RDWR|O_CREAT); |
| if (fd < 0) { |
| if (errno == EROFS) |
| *mount_flags |= EXT2_MF_READONLY; |
| } else |
| close(fd); |
| (void) unlink(TEST_FILE); |
| } |
| retval = 0; |
| errout: |
| endmntent (f); |
| return retval; |
| } |
| |
| static errcode_t check_mntent(const char *file, int *mount_flags, |
| char *mtpt, int mtlen) |
| { |
| errcode_t retval; |
| |
| #ifdef DEBUG |
| retval = check_mntent_file("/tmp/mtab", file, mount_flags, |
| mtpt, mtlen); |
| if (retval == 0) |
| return 0; |
| #endif /* DEBUG */ |
| #ifdef __linux__ |
| retval = check_mntent_file("/proc/mounts", file, mount_flags, |
| mtpt, mtlen); |
| if (retval == 0 && (*mount_flags != 0)) |
| return 0; |
| #endif /* __linux__ */ |
| #if defined(MOUNTED) || defined(_PATH_MOUNTED) |
| #ifndef MOUNTED |
| #define MOUNTED _PATH_MOUNTED |
| #endif /* MOUNTED */ |
| retval = check_mntent_file(MOUNTED, file, mount_flags, mtpt, mtlen); |
| return retval; |
| #else |
| *mount_flags = 0; |
| return 0; |
| #endif /* defined(MOUNTED) || defined(_PATH_MOUNTED) */ |
| } |
| |
| #else |
| #if defined(HAVE_GETMNTINFO) |
| |
| static errcode_t check_getmntinfo(const char *file, int *mount_flags, |
| char *mtpt, int mtlen) |
| { |
| struct statfs *mp; |
| int len, n; |
| const char *s1; |
| char *s2; |
| |
| n = getmntinfo(&mp, MNT_NOWAIT); |
| if (n == 0) |
| return errno; |
| |
| len = sizeof(_PATH_DEV) - 1; |
| s1 = file; |
| if (strncmp(_PATH_DEV, s1, len) == 0) |
| s1 += len; |
| |
| *mount_flags = 0; |
| while (--n >= 0) { |
| s2 = mp->f_mntfromname; |
| if (strncmp(_PATH_DEV, s2, len) == 0) { |
| s2 += len - 1; |
| *s2 = 'r'; |
| } |
| if (strcmp(s1, s2) == 0 || strcmp(s1, &s2[1]) == 0) { |
| *mount_flags = EXT2_MF_MOUNTED; |
| break; |
| } |
| ++mp; |
| } |
| if (mtpt) |
| strncpy(mtpt, mp->f_mntonname, mtlen); |
| return 0; |
| } |
| #endif /* HAVE_GETMNTINFO */ |
| #endif /* HAVE_MNTENT_H */ |
| |
| /* |
| * Check to see if we're dealing with the swap device. |
| */ |
| static int is_swap_device(const char *file) |
| { |
| FILE *f; |
| char buf[1024], *cp; |
| dev_t file_dev; |
| struct stat st_buf; |
| int ret = 0; |
| |
| file_dev = 0; |
| #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ |
| if ((stat(file, &st_buf) == 0) && |
| S_ISBLK(st_buf.st_mode)) |
| file_dev = st_buf.st_rdev; |
| #endif /* __GNU__ */ |
| |
| if (!(f = fopen_for_read("/proc/swaps"))) |
| return 0; |
| /* Skip the first line */ |
| fgets(buf, sizeof(buf), f); |
| while (!feof(f)) { |
| if (!fgets(buf, sizeof(buf), f)) |
| break; |
| if ((cp = strchr(buf, ' ')) != NULL) |
| *cp = 0; |
| if ((cp = strchr(buf, '\t')) != NULL) |
| *cp = 0; |
| if (strcmp(buf, file) == 0) { |
| ret++; |
| break; |
| } |
| #ifndef __GNU__ |
| if (file_dev && (stat(buf, &st_buf) == 0) && |
| S_ISBLK(st_buf.st_mode) && |
| file_dev == st_buf.st_rdev) { |
| ret++; |
| break; |
| } |
| #endif /* __GNU__ */ |
| } |
| fclose(f); |
| return ret; |
| } |
| |
| |
| /* |
| * ext2fs_check_mount_point() returns 1 if the device is mounted, 0 |
| * otherwise. If mtpt is non-NULL, the directory where the device is |
| * mounted is copied to where mtpt is pointing, up to mtlen |
| * characters. |
| */ |
| #ifdef __TURBOC__ |
| # pragma argsused |
| #endif |
| errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags, |
| char *mtpt, int mtlen) |
| { |
| if (is_swap_device(device)) { |
| *mount_flags = EXT2_MF_MOUNTED | EXT2_MF_SWAP; |
| strncpy(mtpt, "<swap>", mtlen); |
| return 0; |
| } |
| #ifdef HAVE_MNTENT_H |
| return check_mntent(device, mount_flags, mtpt, mtlen); |
| #else |
| #ifdef HAVE_GETMNTINFO |
| return check_getmntinfo(device, mount_flags, mtpt, mtlen); |
| #else |
| #ifdef __GNUC__ |
| #warning "Can't use getmntent or getmntinfo to check for mounted filesystems!" |
| #endif |
| *mount_flags = 0; |
| return 0; |
| #endif /* HAVE_GETMNTINFO */ |
| #endif /* HAVE_MNTENT_H */ |
| } |
| |
| /* |
| * ext2fs_check_if_mounted() sets the mount_flags EXT2_MF_MOUNTED, |
| * EXT2_MF_READONLY, and EXT2_MF_ROOT |
| * |
| */ |
| errcode_t ext2fs_check_if_mounted(const char *file, int *mount_flags) |
| { |
| return ext2fs_check_mount_point(file, mount_flags, NULL, 0); |
| } |
| |
| #ifdef DEBUG |
| int main(int argc, char **argv) |
| { |
| int retval, mount_flags; |
| char mntpt[80]; |
| |
| if (argc < 2) { |
| fprintf(stderr, "Usage: %s device\n", argv[0]); |
| exit(1); |
| } |
| |
| mntpt[0] = 0; |
| retval = ext2fs_check_mount_point(argv[1], &mount_flags, |
| mntpt, sizeof(mntpt)); |
| if (retval) { |
| com_err(argv[0], retval, |
| "while calling ext2fs_check_if_mounted"); |
| exit(1); |
| } |
| printf("Device %s reports flags %02x\n", argv[1], mount_flags); |
| if (mount_flags & EXT2_MF_BUSY) |
| printf("\t%s is apparently in use.\n", argv[1]); |
| if (mount_flags & EXT2_MF_MOUNTED) |
| printf("\t%s is mounted.\n", argv[1]); |
| if (mount_flags & EXT2_MF_SWAP) |
| printf("\t%s is a swap device.\n", argv[1]); |
| if (mount_flags & EXT2_MF_READONLY) |
| printf("\t%s is read-only.\n", argv[1]); |
| if (mount_flags & EXT2_MF_ISROOT) |
| printf("\t%s is the root filesystem.\n", argv[1]); |
| if (mntpt[0]) |
| printf("\t%s is mounted on %s.\n", argv[1], mntpt); |
| exit(0); |
| } |
| #endif /* DEBUG */ |
