__mount() — Make a file system available
Standards
| Standards / Extensions | C or C++ | Dependencies |
|---|---|---|
| z/OS® UNIX | both | OS/390® V2R9 |
Format
#define _OPEN_SYS
#include <sys/stat.h>
#include <sys/mntent.h>
int __mount(struct mnte2 *mnte, char *sysname);General description
Adds a file system to the hierarchical file system. The same file system cannot be mounted at more than one place in the hierarchical file system.
In order to mount a file system, the caller must be an authorized program or must be running for a user with appropriate privileges.
Element descriptions
To mount or change the mount of an HFS file in a sysplex, the application should set values in mnte as follows:
- mnt2h_cbid
- The mnte2 control block ID. Initialize it to "MNT2".
- mnt2h_cblen
- The mnte2 size. Initialize it to the size of struct mnte2.
- mh2_cursor
- Contains the internal cursor. This should be set to 0 initially, and must be left unchanged for subsequent calls.
- mnth_devno
- This element contains the device number, if needed.
- mh_bodylen
- The mnte2 size of w_mntent2. Must be initialized to the sizeof the w_mntent2 body.
- rsvd
- This field must be set to all zeros.
- mnt2_fstype
- The file system type.
- mnt2_mode
- File system mount mode. A flag field that specifies the mount
mode and additional mount options:
- mntentfsaunmount
- If it is 1 after the file system is mounted, the file system will be unmounted when a system leaves the sysplex. If it is 0, then the setting of mntentfsnoautomove will be used. See mntentfsnoautomove below. This option can be changed after the file is mounted by changing this bit and setting the request bit, mntentnewauto, to 1 before calling __mount(). If changed to 0, also set mntentfsnoautomove to indicate automove or no move.
- mntentfsclient
- If it is 0, then the file system is a sysplex client. If it
is 1, then the file system is not a sysplex client.
Note: Note that mntentfsclient is not an input parameter.
- mntentfsnoautomove
- If it is 0 after the file system is mounted, it can be moved
automatically. If it is 1 after the file system is mounted, it will
not be moved automatically. The mode can be reversed after the file
is mounted (when mntentfsaunmount is 0) by changing this bit and setting
the request bit, mnte2ntnewauto, to 1 before calling __mount().
Note: The setting of this bit only applies if mntentfsaunmount is 0.
- mntentfsmodenosec
- If it is 1, then the file system will not enforce security checks. If it is 0, then the file system will enforce security checks.
- mntentfsmodeexport
- If it is 0, then the file system has not been exported by DFS. If it is 1, then the file system has been exported by DFS.
- mntentfsmoderdonly
- If it is 0,then the file system is mounted as read/write. If it is 1, then the file system is mounted as read-only.
- mntentfsmodenosuid
- If it is 1, then the SETUID and SETGID mode flags will be ignored for programs that reside in this file system. If it is 0 then the SETUID and SETGID mode flags will be enforced for programs that reside in this file system. This information is returned by the function but should not be changed.
- mnt2_dev
- Device # which stat will return for all files in this file system. Not set on input to __mount().
- mnt2_parentdev
- st_dev of parent file system. Not set on input to __mount().
- mnt2_rootino
- The ino of the mount point. Not set on input to __mount().
- mnt2_status
- status of the file system. The field is not an input parameter. It can be tested on output after a successful request.
- mnt2_ddname
- The ddname specified on mount. 1 to 8 characters are allowed.
- mnt2_fstname
- The name of the file system type specified by the FILESYS statement. The name for the file system that will perform the mount. This 8-character name must match the TYPE operand on a FILESYSTYPE statement in the BPXPRMxx parmlib member for the file system. 1 to 8 characters are allowed.
- mnt2_fsname
- The name of the file system to be mounted; it must be unique within the system. For a hierarchical file system (HFS) data set, this is a 1-to-44-character MVS™ data set name specified as all uppercase letters. This name is terminated with NULL characters.
- mnt2_pathlen
- The length of mount point path.
- mnt2_mountpoint
- The name of the directory where the file system is mounted. 1 to 1023 characters are allowed. Also refers to the mount point directory where the file system will be mounted.
- mnt2_parmoffset
- Offset of mount parameter mnt2_parmreturn from mnt2_fstype. Also refers to a parameter passed to the physical file system that performs the mount. This parameter may not be required. The form and content of the parameter are determined by the physical file system. A hierarchical file system (HFS) data set does not require a parameter.
- mnt2_parmlen
- The length of the mount parameter with size mnt2_parmreturn. Also refers to the length of the parameter argument. The maximum length is 1024 characters. A hierarchical file system data set does not require a parameter.
- mnt2_sysname
- The name of the target system. 1 to 8 characters are allowed. Changing the target system is always supplied as sysname. For all other calls, sysname must be supplied as NULL or the target name will be changed. When sysname is supplied, the mnte2ntchange flag must be set off for a mount function call, or the mnte2ntchange flag must be set on for a change mount function call. When you specify system on a mount it means mount this file on this system or when you specify system on a change mount it means move the file system from where it is currently mounted to this system.
- mnt2_qsystem
- The name of the quiesce system. 1 to 8 characters are allowed but the character(s) are padded with blanks and do not contain a NULL terminator. This field is an output only field from getmntent().
- mnt2_fromsys
- The name of the system from which the file system has moved.
- mnt2_flags
- The field containing the request flags. A flag field that specifies
the change for existing mounted file system:
- mnte2ntnewauto
- This flag instigates a change of mode which will effect the automove state depending on the value that is set for mnte2ntfsnoautomove. See the explanation under mnte2ntfsnoautomove.
- mnte2ntchange
- The request in this w_mntent is a change to existing status or mode. This flag must be set on for all change mount requests. The w_mntent structure needs to modify either the mnte2ntfsname field or the mnte2ntmountpoint and mnte2ndpathlen fields. When the request is to mount a directory, then this flag must be set to off.
- mnt2_status2
- The file system status extensions.
- mnt2_success
- This field is used to return the number of successfully moved file systems when moving a collection of file systems. It is not used in other cases.
- parm_point
- This field contains the mountpoint parameters to be used when mounting a file system. It is a separate field in the mnte2 structure but contiguiously allocated following the w_mnte2 body. The mnt2_parmoffset field contains the offset to the start of parm_point.
- mnt2_syslistlength
- Length of system list.
- mnt2_syslistoffset
- Offset of system list.
- mnt2_aggnamelength
- Length of the aggregate name in mnt2_aggname. The length does not include the NULL terminating character, and is only valid if mnt2_aggnameoffset has a non-zero value.
- mnt2_aggnameoffset
- The offset of mnt2_aggname from w_mntent. If the value is zero, then no aggregate name is returned.
The mnte3 structure can also be used in place of the mnte2 structure. The following mnte3 fields are equivalent to their mnte2 counterparts, with appropriate changes to the header fields to specify the usage of the mnte3 structure:
- mnt3h_cbid
- The mnte3 control block ID. Initialize it to "MNT3".
- mnt3h_cblen
- The mnte3 size. Initialize to the size of struct mnte3.
- mh3_cursor
- mh3_devno
- mh_bodylen
- The mnte3 size of w_mntent3. Must be initialized to the sizeof the w_mntent3 body.
- rsvd
- mnt3_fstype
- mnt3_mode
- mnt3_dev
- mnt3_parentdev
- mnt3_rootino
- mnt3_status
- mnt3_ddname
- mnt3_fstname
- mnt3_fsname
- mnt3_pathlen
- mnt3_mountpoint
- mnt3_parmoffset
- mnt3_parmlen
- mnt3_sysname
- mnt3_qsysname
- mnt3_fromsys
- mnt3_flags
- mnt3_status2
- mnt3_success
Returned value
If successful, __mount() returns 0.
If the __mount() is proceeding asynchronously, it returns 1.
If unsuccessful, __mount() returns -1 and sets errno to one
of the following values:
- Error Code
- Description
- EBUSY
- The specified file system is unavailable.
- EINVAL
- A parameter was incorrectly specified. Verify filesystype and mtm. Another possible reason for this error is that the mount point is the root of a file system or that the file system is already mounted.
- EIO
- An I/O error occurred.
- ELOOP
- A loop exists in symbolic links. This error is issued if more than POSIX_SYMLOOP (defined in the limits.h header file) symbolic links are detected in the resolution of pathname.
- ENOENT
- The mount point does not exist.
- ENOMEM
- There is not enough storage available to save the information required for this file system.
- ENOTDIR
- The mount point is not a directory.
- EPERM
- Appropriate authority is required to issue a mount.
Related information
- limits.h — Standard values for limits on resources
- sys/mntent.h — w_getmntent() function and related structures and constants
- sys/stat.h — z/OS UNIX files and access
- umount() — Remove a virtual file system
- w_getmntent() — Get information on mounted file systems
- w_statfs() — Get the file system status