MOUNT (2)
mount and unmount filesystems.
SYNOPSIS
#include <sys/mount.h>
int mount(const char * specialfile , const char * dir
, const char * filesystemtype , unsigned long rwflag
, const void * data );
int umount(const char * specialfile );
int umount(const char * dir );
DESCRIPTION
mount
attaches the filesystem specified by
specialfile
(which is often a device name)
to the directory specified by
dir .
umount
removes the attachment of the filesystem specified by
specialfile
or
dir .
Only the super-user may mount and unmount filesystems.
The
filesystemtype
argument may take one of the values listed in /proc/filesystems
(like "minix", "ext2", "msdos", "proc", "nfs", "iso9660" etc.).
The
rwflag
argument has the magic number 0xC0ED in the top 16 bits,
and various mount flags (as defined in <linux/fs.h> for libc4 and libc5
and in <sys/mount.h> for glibc2) in the low order 16 bits:
#define MS_RDONLY 1 /* mount read-only */
#define MS_NOSUID 2 /* ignore suid and sgid bits */
#define MS_NODEV 4 /* disallow access to device special files */
#define MS_NOEXEC 8 /* disallow program execution */
#define MS_SYNC 16 /* writes are synced at once */
#define MS_REMOUNT 32 /* alter flags of a mounted FS */
#define MS_MGC_VAL 0xC0ED0000
If the magic number is absent, then the last two arguments are not used.
The
data
argument is interpreted by the different file systems.
RETURN VALUE
On success, zero is returned. On error, -1 is returned, and
errno
is set appropriately.
ERRORS
The error values given below result from filesystem type independent
errors. Each filesystem type may have its own special errors and its
own special behavior. See the kernel source code for details.
EPERM
The user is not the super-user.
ENODEV
Filesystemtype
not configured in the kernel.
ENOTBLK
Specialfile
is not a block device (if a device was required).
EBUSY
Specialfile
is already mounted. Or, it cannot be remounted read-only,
because it still holds files open for writing.
Or, it cannot be mounted on
dir
because
dir
is still busy (it is the working directory of some task,
the mount point of another device, has open files, etc.).
EINVAL
Specialfile
had an invalid superblock.
Or, a remount was attempted, while
specialfile
was not already mounted on
dir .
Or, an umount was attempted, while
dir
was not a mount point.
EFAULT
One of the pointer arguments points outside the user address space.
ENOMEM
The kernel could not allocate a free page to copy filenames or data into.
ENAMETOOLONG
A pathname was longer than MAXPATHLEN.
ENOENT
A pathname was empty or had a nonexistent component.
ENOTDIR
The second argument, or a prefix of the first argument, is not
a directory.
EACCES
A component of a path was not searchable.
Or, mounting a read-only filesystem was attempted without giving the
MS_RDONLY flag.
Or, the block device
Specialfile
is located on a filesystem mounted with the MS_NODEV option.
ENXIO
The major number of the block device
specialfile
is out of range.
EMFILE
(In case no block device is required:)
Table of dummy devices is full.
CONFORMING TO
These functions are Linux-specific and should not be used in
programs intended to be portable.
SEE ALSO
|
