GETMNTENT
NAME
getmntent, setmntent, addmntent, endmntent, hasmntopt,
getmntent_r - get file system descriptor file entry
SYNOPSIS
#include <stdio.h>
#include <mntent.h>
I FILE *setmntent(const char * filename , const char * type );
I struct mntent *getmntent(FILE * fp );
I int addmntent(FILE * fp , const struct mntent * mnt );
I int endmntent(FILE * fp );
I char *hasmntopt(const struct mntent * mnt , const char * opt );
/* GNU extension */
R #define _GNU_SOURCE /* or _SVID_SOURCE or _BSD_SOURCE */
#include <mntent.h>
I struct mntent *getmntent_r(FILE * fp , struct mntent * mntbuf ,
I char * buf , int buflen );
DESCRIPTION
These routines are used to access the file system description file
/etc/fstab and the mounted file system description file
/etc/mtab.
The
R setmntent ()
function opens the file system description file
fp and returns a file pointer which can be used by
R getmntent ().
The argument
type is the type of access
required and can take the same values as the
mode argument of
fopen(3).
The
R getmntent ()
function reads the next line from the file system
description file fp and returns a pointer to a structure
containing the broken out fields from a line in the file.
The pointer
points to a static area of memory which is overwritten by subsequent
calls to
R getmntent ().
The
R addmntent ()
function adds the mntent structure mnt to
the end of the open file fp.
The
R endmntent ()
function closes the file system description file
fp.
The
R hasmntopt ()
function scans the
mnt_opts field (see below)
of the mntent structure
mnt for a substring that matches
opt.
See
<mntent.h> and
mount(8)
for valid mount options.
The reentrant
R getmntent_r ()
function is similar to
R getmntent (),
but stores the struct mount in the provided
*mntbuf
and stores the strings pointed to by the entries in that struct
in the provided array
buf
of size
R buflen .
The
mntent structure is defined in
<mntent.h> as follows:
struct mntent {
char *mnt_fsname; /* name of mounted file system */
char *mnt_dir; /* file system path prefix */
char *mnt_type; /* mount type (see mntent.h) */
char *mnt_opts; /* mount options (see mntent.h) */
int mnt_freq; /* dump frequency in days */
int mnt_passno; /* pass number on parallel fsck */
};
Since fields in the mtab and fstab files are separated by whitespace,
octal escapes are used to represent the four characters space (\040),
tab (\011), newline (\012) and backslash (\134) in those files
when they occur in one of the four strings in a mntent structure.
The routines
R addmntent ()
and
R getmntent ()
will convert
from string representation to escaped representation and back.
RETURN VALUE
The
R getmntent ()
and
R getmntent_r ()
functions return
a pointer to the mntent structure or NULL on failure.
The
R addmntent ()
function returns 0 on success and 1 on failure.
The
R endmntent ()
function always returns 1.
The
R hasmntopt ()
function returns the address of the substring if
a match is found and NULL otherwise.
FILES
/etc/fstab file system description file
/etc/mtab mounted file system description file
CONFORMING TO
The non-reentrant functions are from SunOS 4.1.3.
A routine
R getmntent_r ()
was introduced in HP-UX 10, but it returns an int.
The prototype shown above is glibc-only.
LSB deprecates the functions
R endhostent (),
R sethostent ()
and
R setmntent ().
NOTES
System V also has a
R getmntent ()
function but the calling sequence
differs, and the returned structure is different.
Under System V
/etc/mnttab
is used.
4.4BSD and Digital Unix have a routine
R getmntinfo (),
a wrapper around the system call
R getfsstat ().
SEE ALSO
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