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-rw-r--r--e2fslib/ismounted.c261
1 files changed, 261 insertions, 0 deletions
diff --git a/e2fslib/ismounted.c b/e2fslib/ismounted.c
new file mode 100644
index 0000000..1b145c6
--- /dev/null
+++ b/e2fslib/ismounted.c
@@ -0,0 +1,261 @@
+/*
+ * 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_mntpnt, st_file;
+ errcode_t retval = 0;
+ FILE *f;
+ int fd;
+
+ *mount_flags = 0;
+ if ((f = setmntent (mtab_file, "r")) == NULL)
+ return errno;
+ while ((mnt = getmntent (f)) != NULL)
+ if (strcmp(file, mnt->mnt_fsname) == 0)
+ 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 (stat("/", &st_mntpnt) == 0 && stat(file, &st_file) == 0) {
+ if (st_mntpnt.st_dev == st_file.st_rdev) {
+ *mount_flags = EXT2_MF_MOUNTED;
+ if (mtpt)
+ strncpy(mtpt, "/", mtlen);
+ goto is_root;
+ }
+ }
+#endif
+ goto exit;
+ }
+#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+ /* Validate the entry in case /etc/mtab is out of date */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_mntpnt) < 0) {
+ retval = errno;
+ if (retval == ENOENT) {
+#ifdef DEBUG
+ printf("Bogus entry in %s! (%s does not exist)\n",
+ mtab_file, mnt->mnt_dir);
+#endif
+ retval = 0;
+ }
+ goto exit;
+ }
+ if (stat(file, &st_file) == 0) {
+ if (st_mntpnt.st_dev != st_file.st_rdev) {
+#ifdef DEBUG
+ printf("Bogus entry in %s! (%s not mounted on %s)\n",
+ mtab_file, file, mnt->mnt_dir);
+#endif
+ goto exit;
+ }
+ }
+#endif
+ *mount_flags = EXT2_MF_MOUNTED;
+
+ /* Check to see if the ro option is set */
+ if (hasmntopt(mnt, MNTOPT_RO))
+ *mount_flags |= EXT2_MF_READONLY;
+
+ 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 |= 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;
+exit:
+ 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
+#ifdef __linux__
+ retval = check_mntent_file("/proc/mounts", file, mount_flags,
+ mtpt, mtlen);
+ if (retval == 0)
+ return 0;
+#endif
+ retval = check_mntent_file(MOUNTED, file, mount_flags, mtpt, mtlen);
+ return retval;
+}
+
+#elif 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 */
+
+/*
+ * 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)
+{
+#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
+#warning "Can't use getmntent or getmntinfo to check for mounted filesystems!"
+ *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;
+
+ if (argc < 2) {
+ fprintf(stderr, "Usage: %s device\n", argv[0]);
+ exit(1);
+ }
+
+ retval = ext2fs_check_if_mounted(argv[1], &mount_flags);
+ 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_MOUNTED)
+ printf("\t%s is mounted.\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]);
+
+ exit(0);
+}
+#endif