Manpages - getfsent.3

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

  #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);

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.

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.

For an explanation of the terms used in this section, see *attributes*(7).

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of the same names, that however use a struct checklist instead of a struct fstab, and calls these functions obsolete, superseded by *getmntent*(3).

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.

*getmntent*(3), *fstab*(5)

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