343 lines
7.3 KiB
C
343 lines
7.3 KiB
C
/*
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* file - find type of a file or files - main program.
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*
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* Copyright (c) Ian F. Darwin, 1987.
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* Written by Ian F. Darwin.
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*
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* This software is not subject to any license of the American Telephone
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* and Telegraph Company or of the Regents of the University of California.
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*
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* Permission is granted to anyone to use this software for any purpose on
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* any computer system, and to alter it and redistribute it freely, subject
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* to the following restrictions:
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*
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* 1. The author is not responsible for the consequences of use of this
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* software, no matter how awful, even if they arise from flaws in it.
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*
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* 2. The origin of this software must not be misrepresented, either by
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* explicit claim or by omission. Since few users ever read sources,
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* credits must appear in the documentation.
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*
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* 3. Altered versions must be plainly marked as such, and must not be
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* misrepresented as being the original software. Since few users
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* ever read sources, credits must appear in the documentation.
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*
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* 4. This notice may not be removed or altered.
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*/
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#ifndef lint
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static char *moduleid =
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"@(#)$Id: file.c,v 1.7 1995/07/13 13:22:58 mycroft Exp $";
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#endif /* lint */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/param.h> /* for MAXPATHLEN */
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#include <sys/stat.h>
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#include <fcntl.h> /* for open() */
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#if (__COHERENT__ >= 0x420)
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#include <sys/utime.h>
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#else
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#include <utime.h>
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#endif
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#include <unistd.h> /* for read() */
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#ifdef __ELF__
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#include <elf.h>
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#endif
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#include "patchlevel.h"
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#include "file.h"
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#ifdef S_IFLNK
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# define USAGE "Usage: %s [-vczL] [-f namefile] [-m magicfile] file...\n"
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#else
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# define USAGE "Usage: %s [-vcz] [-f namefile] [-m magicfile] file...\n"
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#endif
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#ifndef MAGIC
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# define MAGIC "/etc/magic"
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#endif
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int /* Global command-line options */
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debug = 0, /* debugging */
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lflag = 0, /* follow Symlinks (BSD only) */
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zflag = 0; /* follow (uncompress) compressed files */
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int /* Misc globals */
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nmagic = 0; /* number of valid magic[]s */
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struct magic *magic; /* array of magic entries */
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char *magicfile; /* where magic be found */
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char *progname; /* used throughout */
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int lineno; /* line number in the magic file */
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static void unwrap __P((char *fn));
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/*
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* main - parse arguments and handle options
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*/
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int
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main(argc, argv)
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int argc;
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char *argv[];
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{
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int c;
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int check = 0, didsomefiles = 0, errflg = 0, ret = 0, app = 0;
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if ((progname = strrchr(argv[0], '/')) != NULL)
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progname++;
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else
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progname = argv[0];
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if (!(magicfile = getenv("MAGIC")))
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magicfile = MAGIC;
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while ((c = getopt(argc, argv, "vcdf:Lm:z")) != EOF)
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switch (c) {
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case 'v':
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(void) fprintf(stdout, "%s-%d.%d\n", progname,
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FILE_VERSION_MAJOR, patchlevel);
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return 1;
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case 'c':
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++check;
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break;
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case 'd':
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++debug;
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break;
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case 'f':
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if (!app) {
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ret = apprentice(magicfile, check);
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if (check)
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exit(ret);
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app = 1;
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}
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unwrap(optarg);
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++didsomefiles;
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break;
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#ifdef S_IFLNK
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case 'L':
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++lflag;
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break;
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#endif
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case 'm':
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magicfile = optarg;
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break;
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case 'z':
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zflag++;
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break;
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case '?':
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default:
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errflg++;
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break;
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}
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if (errflg) {
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(void) fprintf(stderr, USAGE, progname);
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exit(2);
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}
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if (!app) {
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ret = apprentice(magicfile, check);
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if (check)
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exit(ret);
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app = 1;
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}
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if (optind == argc) {
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if (!didsomefiles) {
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(void)fprintf(stderr, USAGE, progname);
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exit(2);
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}
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}
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else {
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int i, wid, nw;
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for (wid = 0, i = optind; i < argc; i++) {
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nw = strlen(argv[i]);
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if (nw > wid)
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wid = nw;
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}
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for (; optind < argc; optind++)
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process(argv[optind], wid);
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}
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return 0;
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}
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/*
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* unwrap -- read a file of filenames, do each one.
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*/
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static void
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unwrap(fn)
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char *fn;
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{
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char buf[MAXPATHLEN];
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FILE *f;
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int wid = 0, cwid;
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if ((f = fopen(fn, "r")) == NULL) {
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error("Cannot open `%s' (%s).\n", fn, strerror(errno));
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/*NOTREACHED*/
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}
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while (fgets(buf, MAXPATHLEN, f) != NULL) {
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cwid = strlen(buf) - 1;
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if (cwid > wid)
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wid = cwid;
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}
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rewind(f);
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while (fgets(buf, MAXPATHLEN, f) != NULL) {
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buf[strlen(buf)-1] = '\0';
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process(buf, wid);
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}
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(void) fclose(f);
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}
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/*
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* process - process input file
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*/
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void
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process(inname, wid)
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const char *inname;
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int wid;
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{
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int fd = 0;
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static const char stdname[] = "standard input";
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unsigned char buf[HOWMANY+1]; /* one extra for terminating '\0' */
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struct utimbuf utbuf;
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struct stat sb;
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int nbytes = 0; /* number of bytes read from a datafile */
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char match = '\0';
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if (strcmp("-", inname) == 0) {
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if (fstat(0, &sb)<0) {
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error("cannot fstat `%s' (%s).\n", stdname,
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strerror(errno));
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/*NOTREACHED*/
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}
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inname = stdname;
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}
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if (wid > 0)
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(void) printf("%s:%*s ", inname,
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(int) (wid - strlen(inname)), "");
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if (inname != stdname) {
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/*
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* first try judging the file based on its filesystem status
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*/
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if (fsmagic(inname, &sb) != 0) {
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putchar('\n');
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return;
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}
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if ((fd = open(inname, O_RDONLY)) < 0) {
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/* We can't open it, but we were able to stat it. */
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if (sb.st_mode & 0002) ckfputs("writeable, ", stdout);
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if (sb.st_mode & 0111) ckfputs("executable, ", stdout);
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ckfprintf(stdout, "can't read `%s' (%s).\n",
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inname, strerror(errno));
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return;
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}
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}
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/*
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* try looking at the first HOWMANY bytes
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*/
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if ((nbytes = read(fd, (char *)buf, HOWMANY)) == -1) {
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error("read failed (%s).\n", strerror(errno));
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/*NOTREACHED*/
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}
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if (nbytes == 0)
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ckfputs("empty", stdout);
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else {
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buf[nbytes++] = '\0'; /* null-terminate it */
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match = tryit(buf, nbytes, zflag);
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}
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#ifdef __ELF__
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/*
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* ELF executables have multiple section headers in arbitrary
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* file locations and thus file(1) cannot determine it from easily.
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* Instead we traverse thru all section headers until a symbol table
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* one is found or else the binary is stripped.
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* XXX: This will not work for binaries of a different byteorder.
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* Should come up with a better fix.
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*/
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if (match == 's' && nbytes > sizeof (Elf32_Ehdr) &&
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buf[EI_MAG0] == ELFMAG0 &&
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buf[EI_MAG1] == ELFMAG1 &&
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buf[EI_MAG2] == ELFMAG2 &&
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buf[EI_MAG3] == ELFMAG3) {
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union {
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long l;
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char c[sizeof (long)];
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} u;
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Elf32_Ehdr elfhdr;
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int stripped = 1;
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u.l = 1;
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(void) memcpy(&elfhdr, buf, sizeof elfhdr);
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/*
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* If the system byteorder does not equal the object byteorder
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* then don't test.
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*/
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if ((u.c[sizeof(long) - 1] + 1) == elfhdr.e_ident[5]) {
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if (lseek(fd, elfhdr.e_shoff, SEEK_SET)<0)
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error("lseek failed (%s).\n", strerror(errno));
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for ( ; elfhdr.e_shnum ; elfhdr.e_shnum--) {
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if (read(fd, buf, elfhdr.e_shentsize)<0)
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error("read failed (%s).\n", strerror(errno));
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if (((Elf32_Shdr *)&buf)->sh_type == SHT_SYMTAB) {
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stripped = 0;
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break;
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}
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}
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if (stripped)
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(void) printf (", stripped");
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}
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}
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#endif
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if (inname != stdname)
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(void) close(fd);
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(void) putchar('\n');
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}
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int
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tryit(buf, nb, zflag)
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unsigned char *buf;
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int nb, zflag;
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{
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/* try compression stuff */
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if (zflag && zmagic(buf, nb))
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return 'z';
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/* try tests in /etc/magic (or surrogate magic file) */
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if (softmagic(buf, nb))
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return 's';
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/* try known keywords, check whether it is ASCII */
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if (ascmagic(buf, nb))
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return 'a';
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/* abandon hope, all ye who remain here */
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ckfputs("data", stdout);
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return '\0';
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}
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