1.\" Copyright (c) 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. 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.\" @(#)devname.3 8.2 (Berkeley) 4/29/95 29.\" 30.Dd February 22, 2005 31.Dt DEVNAME 3 32.Os 33.Sh NAME 34.Nm devname 35.Nd "get device name" 36.Sh LIBRARY 37.Lb libc 38.Sh SYNOPSIS 39.In sys/stat.h 40.In stdlib.h 41.Ft char * 42.Fn devname "dev_t dev" "mode_t type" 43.Ft char * 44.Fn devname_r "dev_t dev" "mode_t type" "char *buf" "int len" 45.Ft char * 46.Fn fdevname "int fd" 47.Ft char * 48.Fn fdevname_r "int fd" "char *buf" "int len" 49.Sh DESCRIPTION 50The 51.Fn devname 52function returns a pointer to the name of the block or character 53device in 54.Pa /dev 55with a device number of 56.Fa dev , 57and a file type matching the one encoded in 58.Fa type 59which must be one of 60.Dv S_IFBLK 61or 62.Dv S_IFCHR . 63To find the right name, 64.Fn devname 65asks the kernel via the 66.Va kern.devname 67sysctl. 68If it is unable to come up with a suitable name, 69it will format the information encapsulated in 70.Fa dev 71and 72.Fa type 73in a human-readable format. 74.Pp 75The 76.Fn fdevname 77and 78.Fn fdevname_r 79function obtains the device name directly from a file descriptor 80pointing to a character device. 81If it is unable to come up with a suitable name, these functions will 82return a NULL pointer. 83.Pp 84.Fn devname 85and 86.Fn fdevname 87return the name stored in a static buffer which will be overwritten 88on subsequent calls. 89.Fn devname_r 90and 91.Fn fdevname_r 92take a buffer and length as argument to avoid this problem. 93.Sh EXAMPLES 94.Bd -literal -compact 95int fd; 96struct stat buf; 97char *name; 98 99 fd = open("/dev/tun"); 100 fstat(fd, &buf); 101 printf("devname is /dev/%s\en", devname(buf.st_rdev, S_IFCHR)); 102 printf("fdevname is /dev/%s\en", fdevname(fd)); 103.Ed 104.Sh SEE ALSO 105.Xr stat 2 106.Sh HISTORY 107The 108.Fn devname 109function appeared in 110.Bx 4.4 . 111The 112.Fn fdevname 113function appeared in 114.Fx 8.0 . 115