usr.bin/file/fsmagic.c

/*
 * fsmagic - magic based on filesystem info - directory, special files, etc.
 *
 * Copyright (c) Ian F. Darwin, 1987.
 * Written by Ian F. Darwin.
 *
 * This software is not subject to any license of the American Telephone
 * and Telegraph Company or of the Regents of the University of California.
 *
 * Permission is granted to anyone to use this software for any purpose on
 * any computer system, and to alter it and redistribute it freely, subject
 * to the following restrictions:
 *
 * 1. The author is not responsible for the consequences of use of this
 *    software, no matter how awful, even if they arise from flaws in it.
 *
 * 2. The origin of this software must not be misrepresented, either by
 *    explicit claim or by omission.  Since few users ever read sources,
 *    credits must appear in the documentation.
 *
 * 3. Altered versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.  Since few users
 *    ever read sources, credits must appear in the documentation.
 *
 * 4. This notice may not be removed or altered.
 */

#include <stdio.h>
#include <sys/types.h>
#ifndef major                   /* if `major' not defined in types.h, */
#include <sys/sysmacros.h>      /* try this one. */
#endif
#ifndef major   /* still not defined? give up, manual intervention needed */
                /* If cc tries to compile this, read and act on it. */
                /* On most systems cpp will discard it automatically */
                Congratulations, you have found a portability bug.
                Please grep /usr/include/sys and edit the above #include
                to point at the file that defines the major macro.
#endif  /*major*/
#include <sys/stat.h>
#include "file.h"

#ifndef lint
static char *moduleid =
        "@(#)$Header: fsmagic.c,v 1.8 88/01/15 12:13:52 ian Exp $";
#endif  /* lint */

extern char *progname;
extern char *ckfmsg, *magicfile;
extern int debug;
extern FILE *efopen();

fsmagic(fn)
char *fn;
{
        extern struct stat statbuf;

        /*
         * Fstat is cheaper but fails for files you don't have read perms on.
         * On 4.2BSD and similar systems, use lstat() so identify symlinks.
         */
#ifdef  S_IFLNK
        if (lstat(fn, &statbuf) <0)
#else
        if (stat(fn, &statbuf) <0)
#endif
                {
                        warning("can't stat", "");
                        return -1;
                }

        if (statbuf.st_mode & S_ISUID) ckfputs("setuid ", stdout);
        if (statbuf.st_mode & S_ISGID) ckfputs("setgid ", stdout);
        if (statbuf.st_mode & S_ISVTX) ckfputs("sticky ", stdout);

        switch (statbuf.st_mode & S_IFMT) {
        case S_IFDIR:
                ckfputs("directory", stdout);
                return 1;
        case S_IFCHR:
                (void) printf("character special (%d/%d)",
                        major(statbuf.st_rdev), minor(statbuf.st_rdev));
                return 1;
        case S_IFBLK:
                (void) printf("block special (%d/%d)",
                        major(statbuf.st_rdev), minor(statbuf.st_rdev));
                return 1;
        /* TODO add code to handle V7 MUX and Blit MUX files */
#ifdef  S_IFIFO
        case S_IFIFO:
                ckfputs("fifo (named pipe)", stdout);
                return 1;
#endif
#ifdef  S_IFLNK
        case S_IFLNK:
                ckfputs("symbolic link", stdout);
                return 1;
#endif
#ifdef  S_IFSOCK
        case S_IFSOCK:
                ckfputs("socket", stdout);
                return 1;
#endif
        case S_IFREG:
                break;
        default:
                warning("invalid st_mode %d in statbuf!", statbuf.st_mode);
        }

        /*
         * regular file, check next possibility
         */
        if (statbuf.st_size == 0) {
                ckfputs("empty", stdout);
                return 1;
        }
        return 0;
}