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IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)getdirentries.2 8.2 (Berkeley) 5/3/95 29.\" $FreeBSD: src/lib/libc/sys/getdirentries.2,v 1.12.2.6 2001/12/14 18:34:00 ru Exp $ 30.\" $DragonFly: src/lib/libc/sys/getdirentries.2,v 1.8 2007/12/23 15:31:28 swildner Exp $ 31.\" 32.Dd July 31, 2006 33.Dt GETDIRENTRIES 2 34.Os 35.Sh NAME 36.Nm getdirentries , 37.Nm getdents 38.Nd "get directory entries in a filesystem independent format" 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In sys/types.h 43.In dirent.h 44.Ft int 45.Fn getdirentries "int fd" "char *buf" "int nbytes" "long *basep" 46.Ft int 47.Fn getdents "int fd" "char *buf" "int nbytes" 48.Ft size_t 49.Fn _DIRENT_DIRSIZ "struct dirent *dp" 50.Ft struct dirent * 51.Fn _DIRENT_NEXT "struct dirent *dp" 52.Sh DESCRIPTION 53The 54.Fn getdirentries 55and 56.Fn getdents 57functions read directory entries from the directory 58referenced by the file descriptor 59.Fa fd 60into the buffer pointed to by 61.Fa buf , 62in a filesystem independent format. 63Up to 64.Fa nbytes 65of data will be transferred. 66The 67.Fa nbytes 68argument must be greater than or equal to the 69block size associated with the file, 70see 71.Xr stat 2 . 72Some filesystems may not support these functions 73with buffers smaller than this size. 74.Pp 75The data in the buffer is a series of 76.Em dirent 77structures each containing the following entries: 78.Bd -literal -offset indent 79ino_t d_fileno; 80u_int8_t d_type; 81u_int8_t d_namlen; 82char d_name[...]; /* see below */ 83.Ed 84.Pp 85The 86.Fa d_fileno 87entry is a number which is unique for each 88distinct file in the filesystem. 89Files that are linked by hard links (see 90.Xr link 2 ) 91have the same 92.Fa d_fileno . 93The 94.Fa d_type 95entry is the type of the file pointed to by the directory record. 96The file type values are defined in 97.In sys/dirent.h . 98The 99.Fa d_name 100entry contains a null terminated file name. 101The 102.Fa d_namlen 103entry specifies the length of the file name excluding the null byte. 104Thus the actual size of 105.Fa d_name 106may vary from 1 to 107.Dv MAXNAMELEN 108\&+ 1. 109.Pp 110Entries may be separated by extra space. 111To get the total size of a 112.Fa dirent 113structure, use the 114.Nm _DIRENT_DIRSIZ 115macro, or use 116.Nm _DIRENT_NEXT 117to get a pointer to the following 118.Fa dirent 119structure. 120.Pp 121The actual number of bytes transferred is returned. 122The current position pointer associated with 123.Fa fd 124is set to point to the next block of entries. 125The pointer may not advance by the number of bytes returned by 126.Fn getdirentries 127or 128.Fn getdents . 129A value of zero is returned when 130the end of the directory has been reached. 131.Pp 132The 133.Fn getdirentries 134function writes the position of the block read into the location pointed to by 135.Fa basep . 136Alternatively, the current position pointer may be set and retrieved by 137.Xr lseek 2 . 138The current position pointer should only be set to a value returned by 139.Xr lseek 2 , 140a value returned in the location pointed to by 141.Fa basep 142.Pf ( Fn getdirentries 143only) 144or zero. 145.Sh RETURN VALUES 146If successful, the number of bytes actually transferred is returned. 147Otherwise, -1 is returned and the global variable 148.Va errno 149is set to indicate the error. 150.Sh ERRORS 151.Fn Getdirentries 152will fail if: 153.Bl -tag -width Er 154.It Bq Er EBADF 155.Fa fd 156is not a valid file descriptor open for reading. 157.It Bq Er EFAULT 158Either 159.Fa buf 160or 161.Fa basep 162point outside the allocated address space. 163.It Bq Er EINVAL 164The file referenced by 165.Fa fd 166is not a directory, or 167.Fa nbytes 168is too small for returning a directory entry or block of entries, 169or the current position pointer is invalid. 170.It Bq Er EIO 171An 172.Tn I/O 173error occurred while reading from or writing to the file system. 174.El 175.Sh SEE ALSO 176.Xr lseek 2 , 177.Xr open 2 178.Sh HISTORY 179The 180.Fn getdirentries 181function first appeared in 182.Bx 4.4 . 183The 184.Fn getdents 185function first appeared in 186.Fx 3.0 . 187.Sh BUGS 188Unfortunately, 189.Fa *basep 190is only 32 bits wide on 32 bit platforms and 191may not be wide enough to accommodate the directory position cookie. 192Modern users should use 193.Xr lseek 2 . 194to retrieve and set the seek position within the directory. 195The seek offset is 64 bits wide on all platforms. 196