1 files changed, 387 insertions, 0 deletions

diff --git a/libblkid/ismounted.c b/libblkid/ismounted.c
new file mode 100644
index 000000000..d9f1f57d0
--- /dev/null
+++ b/libblkid/ismounted.c
@@ -0,0 +1,387 @@
+/*
+ * ismounted.c --- Check to see if the filesystem was mounted
+ *
+ * Copyright (C) 1995,1996,1997,1998,1999,2000,2008 Theodore Ts'o.
+ *
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <fcntl.h>
+#ifdef HAVE_MNTENT_H
+#include <mntent.h>
+#endif
+#include <string.h>
+#include <sys/stat.h>
+#include <ctype.h>
+#include <sys/param.h>
+#ifdef __APPLE__
+#include <sys/ucred.h>
+#include <sys/mount.h>
+#endif
+
+#include "pathnames.h"
+#include "ismounted.h"
+#include "c.h"
+#ifdef __linux__
+# include "loopdev.h"
+#endif
+
+
+
+#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 int check_mntent_file(const char *mtab_file, const char *file,
+				   int *mount_flags, char *mtpt, int mtlen)
+{
+	struct mntent	*mnt;
+	struct stat	st_buf;
+	int		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 (mnt->mnt_fsname[0] != '/')
+			continue;
+		if (strcmp(file, mnt->mnt_fsname) == 0)
+			break;
+		if (stat(mnt->mnt_fsname, &st_buf) != 0)
+			continue;
+
+		if (S_ISBLK(st_buf.st_mode)) {
+#ifndef __GNU__
+			if (file_rdev && file_rdev == st_buf.st_rdev)
+				break;
+#ifdef __linux__
+			/* maybe the file is loopdev backing file */
+			if (file_dev
+			    && major(st_buf.st_rdev) == LOOPDEV_MAJOR
+			    && loopdev_is_used(mnt->mnt_fsname, file, 0, 0))
+				break;
+#endif /* __linux__ */
+#endif	/* __GNU__ */
+		} else {
+			if (file_dev && ((file_dev == st_buf.st_dev) &&
+					 (file_ino == st_buf.st_ino)))
+				break;
+		}
+	}
+
+	if (mnt == NULL) {
+#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 &&
+		    st_buf.st_dev == file_rdev) {
+			*mount_flags = 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 = MF_MOUNTED;
+
+#ifdef MNTOPT_RO
+	/* Check to see if the ro option is set */
+	if (hasmntopt(mnt, MNTOPT_RO))
+		*mount_flags |= 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 (!strcmp(mnt->mnt_dir, "/")) {
+is_root:
+#define TEST_FILE "/.ismount-test-file"
+		*mount_flags |= MF_ISROOT;
+		fd = open(TEST_FILE, O_RDWR|O_CREAT, 0600);
+		if (fd < 0) {
+			if (errno == EROFS)
+				*mount_flags |= MF_READONLY;
+		} else
+			close(fd);
+		(void) unlink(TEST_FILE);
+	}
+	retval = 0;
+errout:
+	endmntent (f);
+	return retval;
+}
+
+static int check_mntent(const char *file, int *mount_flags,
+			      char *mtpt, int mtlen)
+{
+	int	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;
+	if (access("/proc/mounts", R_OK) == 0) {
+		*mount_flags = 0;
+		return retval;
+	}
+#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 int 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 = 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("/proc/swaps", "r")))
+		return 0;
+	/* Skip the first line */
+	if (!fgets(buf, sizeof(buf), f))
+		goto leave;
+	if (*buf && strncmp(buf, "Filename\t", 9))
+		/* Linux <=2.6.19 contained a bug in the /proc/swaps
+		 * code where the header would not be displayed
+		 */
+		goto valid_first_line;
+
+	while (fgets(buf, sizeof(buf), f)) {
+valid_first_line:
+		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__ */
+	}
+
+leave:
+	fclose(f);
+	return ret;
+}
+
+
+/*
+ * check_mount_point() fills determines if the device is mounted or otherwise
+ * busy, and fills in mount_flags with one or more of the following flags:
+ * MF_MOUNTED, MF_ISROOT, MF_READONLY, MF_SWAP, and MF_BUSY.  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
+int check_mount_point(const char *device, int *mount_flags,
+				  char *mtpt, int mtlen)
+{
+	struct stat	st_buf;
+	int	retval = 0;
+	int		fd;
+
+	if (is_swap_device(device)) {
+		*mount_flags = MF_MOUNTED | MF_SWAP;
+		strncpy(mtpt, "<swap>", mtlen);
+	} else {
+#ifdef HAVE_MNTENT_H
+		retval = check_mntent(device, mount_flags, mtpt, mtlen);
+#else
+#ifdef HAVE_GETMNTINFO
+		retval = 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;
+#endif /* HAVE_GETMNTINFO */
+#endif /* HAVE_MNTENT_H */
+	}
+	if (retval)
+		return retval;
+
+#ifdef __linux__ /* This only works on Linux 2.6+ systems */
+	if ((stat(device, &st_buf) != 0) ||
+	    !S_ISBLK(st_buf.st_mode))
+		return 0;
+	fd = open(device, O_RDONLY | O_EXCL);
+	if (fd < 0) {
+		if (errno == EBUSY)
+			*mount_flags |= MF_BUSY;
+	} else
+		close(fd);
+#endif
+
+	return 0;
+}
+
+int is_mounted(const char *file)
+{
+	int	retval;
+	int	mount_flags = 0;
+
+	retval = check_mount_point(file, &mount_flags, NULL, 0);
+	if (retval)
+		return 0;
+	return mount_flags & MF_MOUNTED;
+}
+
+#ifdef TEST_PROGRAM
+int main(int argc, char **argv)
+{
+	int flags = 0;
+	char devname[PATH_MAX];
+
+	if (argc < 2) {
+		fprintf(stderr, "Usage: %s device\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	if (check_mount_point(argv[1], &flags, devname, sizeof(devname)) == 0 &&
+	    (flags & MF_MOUNTED)) {
+		if (flags & MF_SWAP)
+			printf("used swap device\n");
+		else
+			printf("mounted on %s\n", devname);
+		return EXIT_SUCCESS;
+	}
+
+	printf("not mounted\n");
+	return EXIT_FAILURE;
+}
+#endif /* DEBUG */