mount(2) DG/UX R4.11MU05 mount(2)
NAME
mount - mount a file system
SYNOPSIS
#include <sys/mount.h>
int mount (const char *special, const char *path, int flag,
const char fstype, const char *dataptr, int datalen);
where:
special Address of a pathname of a block special file
path A string indicating the file on which to mount the file
system
flag A bitmask of flags indicating mount options
fstype The type name for the file system
dataptr An block address for file system specific data
datalen The length of the data specified at dataptr
DESCRIPTION
Mount adds the file system device identified by special to the set of
active file system devices, using the file identified by path as the
mount point. The flag contains a bitmask of flags (see below);
ordinarily the MS_DATA flag must be set. The dataptr and datalen
describe the block address and the length of file system specific
data. Mount has the following consequences:
· The filename store contained on special is added to the system
filename store. Thus, all files contained on special can be
named.
· References to the mount point will refer to the root directory
on the mounted file system device.
· The original sub-tree under the mount point disappears from
the system filename store. However, the files in that subtree
remain unchanged. These files still exist, but can no longer
be named. Already opened file descriptors for these files
will remain valid.
Flag contains the following bitmap options, defined in <sys/mount.h>:
MSDATA
This is ordinarily required; it indicates the arguments
fstype, dataptr, and datalen are being used. (For backward
compatibility, if this flag is not set, then fstype is assumed
to be the same as the root file system, and dataptr and
datalen assumed to be zero.)
MSRDONLY
If this is set, then any writing to the file system is not
allowed. Otherwise writing is controlled by individual file
permissions.
MSNOSUID
This indicates the file system does not support setuid and
setgid semantics.
MSREMOUNT
This flag indicates the file system is already mounted and any
associated attributes of the mount should be modified to that
of this call. This is used to change options, however not all
changes are possible. For example, it is impossible to change
a currently mounted file system from read/write to read-only.
In addition, local file systems do not support the remount
option at all.
If an error occurs, no changes are made.
ACCESS CONTROL
In the case where the string namefs is provided for the value of
fstype, the effective user id of the calling process must be the
owner of path and have write permission to path, or the calling
process must have appropriate privilege. If fstype is anything else,
the calling process must have appropriate privilege to successfully
execute this system call.
On a generic DG/UX system, appropriate privilege means that the
effective user id of the calling process is 0. (See the
appropriateprivilege(5) man page for more information.)
On systems supporting the DG/UX Capability Option, appropriate
privilege is defined as having one or more specific capabilities
enabled in the effective capability set of the calling process. See
capdefaults(5) for the default capability for this system call.
RETURN VALUE
0 Completed successfully.
-1 An error occurred. errno is set to indicate the error.
DIAGNOSTICS
Errno may be set to one of the following error codes:
EBUSY Path is being used by another mount, is someone's
current working path or is otherwise open for access.
EBUSY The device associated with special is currently
mounted.
EBUSY The system limit on mounted devices has been reached.
EINVAL System information on the file system is bad.
ENOSPC Not enough memory was available to read system
information from the file system.
EIO An I/O error occurred while reading system information
from the file system.
ENOTBLK Special is not a block special device.
ENOTDIR Path is not a directory and the file system type
requires a directory.
ENXIO The device associated with special does not exist.
EPERM Permission to mount a file system device is denied to
the calling process.
EROFS Path resides on a read-only file system.
ENOENT Either special or path do not exist.
ENOENT A non-terminal component of either special or path
does not exist.
ENOTDIR A non-terminal component of either special or path was
not a path or symbolic link.
ENAMETOOLONG Either special or path exceeds the length limit for
pathnames.
ENAMETOOLONG A component of either special or path exceeds the
length limit for filenames.
ENOMEM There are not enough system resources to resolve
either special or path or to expand a symbolic link.
ELOOP The number of symbolic links encountered while
resolving either special or path exceeded MAXSYMLINKS.
A symbolic link cycle is suspected.
EPERM Either special or path contains a character not in the
allowed character set.
EFAULT Either special or path does not completely reside in
the process's address space or either special or path
does not terminate in the process's address space.
SEE ALSO
dgmount(2), umount(2), fattach(3C), appropriateprivilege(5).
capdefaults(5).
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