fhopen(2) - NetBSD Manual Pages

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FHOPEN(2)                 NetBSD System Calls Manual                 FHOPEN(2)


NAME

     fhopen, fhstat, fhstatvfs -- access file via file handle


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

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

     int
     fhopen(const void *fhp, size_t fh_size, int flags);

     #include <sys/stat.h>

     int
     fhstat(const void *fhp, size_t fh_size, struct stat *sb);

     #include <sys/statvfs.h>

     int
     fhstatvfs(const void *fhp, size_t fh_size, struct statvfs *buf);

     int
     fhstatvfs1(const void *fhp, size_t fh_size, struct statvfs *buf,
         int flags);


DESCRIPTION

     These functions provide a means to access a file given the opaque file
     handle fhp and the size fh_size of the opaque object as returned by
     getfh(2).  As this method bypasses directory access restrictions, these
     calls are restricted to the superuser.

     fhopen() opens the file referenced by fhp for reading and/or writing as
     specified by the argument flags and returns the file descriptor to the
     calling process.  The flags are specified by or'ing together the flags
     used for the open(2) call.  All said flags are valid except for O_CREAT.

     fhstat(), fhstatvfs(), and fhstatvfs1() provide the functionality of the
     fstat(2), fstatvfs(2), and fstatvfs1(2) calls except that they return
     information for the file referred to by fhp rather than an open file.


RETURN VALUES

     Upon successful completion, fhopen() returns the file descriptor for the
     opened file, while fhstat(), fhstatvfs(), and fhstatvfs1() return 0.
     Otherwise, -1 is returned and errno is set to indicate the error.


ERRORS

     In addition to the errors returned by open(2), fstat(2), fstatvfs(2), and
     fstatvfs1(2), respectively, fhopen(), fhstat(), fhstatvfs(), and
     fhstatvfs1() will return

     [EINVAL]           Calling fhopen() with O_CREAT set or invalid fh_size.

     [ESTALE]           The file handle fhp is no longer valid.


SEE ALSO

     fstat(2), fstatvfs(2), fstatvfs1(2), getfh(2), open(2)


HISTORY

     The fhopen(), and fhstat() functions first appeared in NetBSD 1.5.  The
     fhstatvfs() function replaced fhstatfs() in NetBSD 3.0.

NetBSD 6.0                      August 5, 2009                      NetBSD 6.0