GETMNTENT(3X)

NAME

getmntent, setmntent, addmntent, endmntent, hasmntopt − get file system descriptor file entry

SYNOPSIS

#include <stdio.h>
#include <mntent.h>
FILE *setmntent(filename, type)
char *filename;
char *type;
struct mntent *getmntent(filep)
FILE *filep;
int addmntent(filep, mnt)
FILE *filep;
struct mntent *mnt;
char *hasmntopt(mnt, opt)
struct mntent *mnt;
char *opt;
int endmntent(filep)
FILE *filep;

DESCRIPTION

These routines replace the getfsent routines for accessing the file system description file /etc/checklist. They are also used to access the mounted file system description file /etc/mnttab.

Setmntent opens a file system description file and returns a file pointer which can then be used with getmntent, addmntent, or endmntent. The type argument is the same as in fopen(3C). Getmntent reads the next line from filep and returns a pointer to an object with the following structure containing the broken-out fields of a line in the filesystem description file, <mntent.h>. The fields have meanings described in checklist(4).

struct mntent {

char	*mnt_fsname;	/* file system name */
char	*mnt_dir;	/* file system path prefix */
char	*mnt_type;	/* hfs, nfs, swap, or xx */
char	*mnt_opts;	/* ro, suid, etc. */
int	mnt_freq;	/* dump frequency, in days */
int	mnt_passno;	/* pass number on parallel fsck */
long	mnt_time;	/* When file system was mounted; */
		/* see mnttab(4). */

};

Addmntent adds the mntent structure mnt to the end of the open file filep. Note that filep must be opened for writing. Hasmntopt scans the mnt_opts field of the mntent structure mnt for a substring that matches opt. It returns the address of the substring if a match is found, 0 otherwise. Endmntent closes the file.

The following definitions are provided in <mntent.h>:

#define MNT_CHECKLIST	"/etc/checklist"
#define MNT_MNTTAB	"/etc/mnttab"
#define MNTMAXSTR	128	/* Max size string in mntent */
#define MNTTYPE_HFS	"hfs"	/* HFS file system */
#define MNTTYPE_NFS	"nfs"	/* Network file system */
#define MNTTYPE_SWAP	"swap"	/* Swap device */
#define MNTTYPE_SWAPFS	"swapfs"	/* File system swap */
#define MNTTYPE_IGNORE	"ignore"	/* Ignore this entry */
#define MNTOPT_DEFAULTS	"defaults"	/* Use all default options */
#define MNTOPT_RO	"ro"	/* Read only */
#define MNTOPT_RW	"rw"	/* Read/write */
#define MNTOPT_SUID	"suid"	/* Set uid allowed */
#define MNTOPT_NOSUID	"nosuid"	/* No set uid allowed */

The following definitions are provided for file system swap in <mntent.h>:

#define MNTOPT_MIN	"min"	/* minimum file system swap */
#define MNTOPT_LIM	"lim"	/* maximum file system swap */
#define MNTOPT_RES	"res"	/* reserve space for file system */
#define MNTOPT_PRI	"pri"	/* file system swap priority */

NETWORKING FEATURES

NFS

The following definitions are provided in <mntent.h>:

#define MNTOPT_BG	"bg"	/* Retry mount in background */
#define MNTOPT_FG	"fg"	/* Retry mount in foreground */
#define MNTOPT_RETRY	"retry"	/* Number of retries allowed */
#define MNTOPT_RSIZE	"rsize"	/* Read buffer size in bytes */
#define MNTOPT_WSIZE	"wsize"	/* Write buffer size in bytes*/
#define MNTOPT_TIMEO	"timeo"	/* Timeout in 1/10 seconds */
#define MNTOPT_RETRANS	"retrans"	/* Number of retransmissions */
#define MNTOPT_PORT	"port"	/* Server’s IP NFS port */
#define MNTOPT_SOFT	"soft"	/* Soft mount */
#define MNTOPT_HARD	"hard"	/* Hard mount */
#define MNTOPT_INTR	"intr"	/* Interruptable hard mounts */
#define MNTOPT_NOINTR	"nointr"	/* Uninterruptable hard mounts*/
#define MNTOPT_DEVS	"devs"	/* Device file access allowed */
#define MNTOPT_NODEVS	"nodevs"	/* No device file access allowed */

RETURN VALUE

Setmntent returns a null pointer on error. Getmntent returns a null pointer on error or EOF. Otherwise, getmntent returns a pointer to a mntent structure. Some of the fields comprising a mntent structure are optional in /etc/checklist and /etc/mnttab. In the supplied structure, such missing character pointer fields are set to NULL and missing integer fields are set to −1. Addmntent returns 1 on error. Endmntent returns 1.

WARNINGS

The returned mntent structure points to static information that is overwritten in each call.

AUTHOR

Addmntent, endmntent, getmntent, hasmntopt and setmntent were developed by The University of California, Berkeley, Sun Microsystems, Inc. and HP.

FILES

/etc/checklist
/etc/mnttab

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