getfsent(3) — Linux manual page
getfsent(3) Library Functions Manual getfsent(3)
NAME
getfsent, getfsspec, getfsfile, setfsent, endfsent - handle fstab
entries
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#include <fstab.h>
int setfsent(void);
struct fstab *getfsent(void);
void endfsent(void);
struct fstab *getfsfile(const char *mount_point);
struct fstab *getfsspec(const char *special_file);
DESCRIPTION
These functions read from the file /etc/fstab. The struct fstab
is defined by:
struct fstab {
char *fs_spec; /* block device name */
char *fs_file; /* mount point */
char *fs_vfstype; /* filesystem type */
char *fs_mntops; /* mount options */
const char *fs_type; /* rw/rq/ro/sw/xx option */
int fs_freq; /* dump frequency, in days */
int fs_passno; /* pass number on parallel dump */
};
Here the field fs_type contains (on a *BSD system) one of the
five strings "rw", "rq", "ro", "sw", "xx" (read-write, read-write
with quota, read-only, swap, ignore).
The function setfsent() opens the file when required and
positions it at the first line.
The function getfsent() parses the next line from the file.
(After opening it when required.)
The function endfsent() closes the file when required.
The function getfsspec() searches the file from the start and
returns the first entry found for which the fs_spec field matches
the special_file argument.
The function getfsfile() searches the file from the start and
returns the first entry found for which the fs_file field matches
the mount_point argument.
RETURN VALUE
Upon success, the functions getfsent(), getfsfile(), and
getfsspec() return a pointer to a struct fstab, while setfsent()
returns 1. Upon failure or end-of-file, these functions return
NULL and 0, respectively.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────┬───────────────┬────────────────────────────────┐
│ Interface │ Attribute │ Value │
├──────────────┼───────────────┼────────────────────────────────┤
│ endfsent(), │ Thread safety │ MT-Unsafe race:fsent │
│ setfsent() │ │ │
├──────────────┼───────────────┼────────────────────────────────┤
│ getfsent(), │ Thread safety │ MT-Unsafe race:fsent locale │
│ getfsspec(), │ │ │
│ getfsfile() │ │ │
└──────────────┴───────────────┴────────────────────────────────┘
VERSIONS
Several operating systems have these functions, for example,
*BSD, SunOS, Digital UNIX, AIX (which also has a getfstype()).
HP-UX has functions of the same names, that however use a struct
checklist instead of a struct fstab, and calls these functions
obsolete, superseded by getmntent(3).
STANDARDS
None.
HISTORY
The getfsent() function appeared in 4.0BSD; the other four
functions appeared in 4.3BSD.
NOTES
These functions are not thread-safe.
Since Linux allows mounting a block special device in several
places, and since several devices can have the same mount point,
where the last device with a given mount point is the interesting
one, while getfsfile() and getfsspec() only return the first
occurrence, these two functions are not suitable for use under
Linux.
SEE ALSO
getmntent(3), fstab(5)
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