getfsent(3) Library Functions Manual getfsent(3)
NAME
getfsent, getfsspec, getfsfile, setfsent, endfsent - handle fstab en-
tries
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 de-
fined 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 spe-
cial_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, respec-
tively.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
┌─────────────┬───────────────┬────────────────────────────────────────┐
│Interface │ Attribute │ Value │
├─────────────┼───────────────┼────────────────────────────────────────┤
│endfsent(), │ Thread safety │ MT-Unsafe race:fsent │
│setfsent() │ │ │
├─────────────┼───────────────┼────────────────────────────────────────┤
│getfsent(), │ Thread safety │ MT-Unsafe race:fsent locale │
│getfsspec(), │ │ │
│getfsfile() │ │ │
└─────────────┴───────────────┴────────────────────────────────────────┘
STANDARDS
These functions are not in POSIX.1. Several operating systems have
them, 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).
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 getfs-
file() and getfsspec() only return the first occurrence, these two
functions are not suitable for use under Linux.
SEE ALSO
getmntent(3), fstab(5)
Linux man-pages 6.03 2022-12-15 getfsent(3)
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