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Manual Pages  — GETFH


getfh, lgetfh, getfhat – get file handle



Standard C Library (libc, -lc)


#include <sys/param.h>
#include <sys/mount.h>

getfh(const char *path, fhandle_t *fhp);

lgetfh(const char *path, fhandle_t *fhp);

getfhat(int fd, const char *path, fhandle_t *fhp, int flag);


The getfh() system call returns a file handle for the specified file or directory in the file handle pointed to by fhp.

The lgetfh() system call is like getfh() except in the case where the named file is a symbolic link, in which case lgetfh() returns information about the link, while getfh() returns information about the file the link references.

The getfhat() system call is equivalent to getfh() and lgetfh() except when the path specifies a relative path, or the AT_BENEATH flag is provided. For getfhat() and relative path, the status is retrieved from a file relative to the directory associated with the file descriptor fd instead of the current working directory. For AT_BENEATH and absolute path, the status is retrieved from a file specified by the path, but additional permission checks are performed, see below.

The values for the flag are constructed by a bitwise-inclusive OR of flags from this list, defined in <fcntl.h>:
  If path names a symbolic link, the status of the symbolic link is returned.
  Only stat files and directories below the topping directory. See the description of the O_BENEATH flag in the open(2) manual page.

If getfhat() is passed the special value AT_FDCWD in the fd parameter, the current working directory is used and the behavior is identical to a call to getfth() or lgetfh() respectively, depending on whether or not the AT_SYMLINK_NOFOLLOW bit is set in flag.

When getfhat() is called with an absolute path without the AT_BENEATH flag, it ignores the fd argument. When AT_BENEATH is specified with an absolute path, a directory passed by the fd argument is used as the topping point for the resolution. These system calls are restricted to the superuser.


Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.


The getfh() and lgetfh() system calls fail if one or more of the following are true:
  A component of the path prefix of path is not a directory.
  The length of a component of path exceeds 255 characters, or the length of path exceeds 1023 characters.
  The file referred to by path does not exist.
  Search permission is denied for a component of the path prefix of path.
  Too many symbolic links were encountered in translating path.
  The fhp argument points to an invalid address.
  The path argument points to an invalid address.
[EIO] An I/O error occurred while reading from or writing to the file system.
  Corrupted data was detected while reading from the file system.
  The file handle fhp is no longer valid.

In addition to the errors returned by getfh(), and lgetfh(), the getfhat() system call may fail if:
  The path argument does not specify an absolute path and the fd argument, is neither AT_FDCWD nor a valid file descriptor open for searching.
  The value of the flag argument is not valid.
  The path argument is not an absolute path and fd is neither AT_FDCWD nor a file descriptor associated with a directory.


fhopen(2), open(2), stat(2)


The getfh() system call first appeared in BSD 4.4 .

GETFH (2) March 30, 2020

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