getfsent(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

GETFSENT(3)             Linux Programmer's Manual            GETFSENT(3)

NAME         top

       getfsent, getfsspec, getfsfile, setfsent, endfsent - handle fstab
       entries

SYNOPSIS         top

       #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         top

       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         top

       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         top

       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()  │               │                                  │
       └─────────────┴───────────────┴──────────────────────────────────┘

CONFORMING TO         top

       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         top

       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         top

       getmntent(3), fstab(5)

COLOPHON         top

       This page is part of release 5.11 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

GNU                            2021-03-22                    GETFSENT(3)