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IABSD.fr/src/usr.bin/compress/main.c

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  • Author : gkoehler
    Date : 2023-11-11 02:52:55
    Hash : eaf8e725
    Message : Ignore -N in "gzip -dN <in.gz" and "zcat -N in.gz" Have -c override -N, like other gzip implementations. Before, our -N (decompress to stored name) overrode -c (cat to stdout) and crashed with a pledge violation, because the pledge for -c excludes wpath. Guilherme Janczak reported the pledge violation in July 2022 and provided a diff to prevent it, along with a regress test. I rewrote the diff and expanded the regress. ok kn@ millert@

  • usr.bin/compress/main.c
  • /*	$OpenBSD: main.c,v 1.106 2023/11/11 02:52:55 gkoehler Exp $	*/
    
    /*
     * Copyright (c) 1992, 1993
     *	The Regents of the University of California.  All rights reserved.
     * Copyright (c) 1997-2002 Michael Shalayeff
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
     * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
     * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     * THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include <sys/time.h>
    #include <sys/stat.h>
    
    #include <getopt.h>
    #include <err.h>
    #include <errno.h>
    #include <fts.h>
    #include <libgen.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <stdbool.h>
    #include <string.h>
    #include <unistd.h>
    #include <limits.h>
    #include <fcntl.h>
    #include <paths.h>
    #include "compress.h"
    
    #define min(a,b) ((a) < (b)? (a) : (b))
    
    enum program_mode pmode;
    
    static int cat, decomp, kflag, pipin, force, verbose, testmode, list, recurse;
    static int storename;
    static char suffix[16];
    extern char *__progname;
    
    const struct compressor {
    	const char *name;
    	const char *suffix;
    	const u_char *magic;
    	const char *opts;
    	void *(*ropen)(int, char *, int);
    	int (*read)(void *, char *, int);
    #ifndef SMALL
    	void *(*wopen)(int, char *, int, u_int32_t);
    	int (*write)(void *, const char *, int);
    #endif
    	int (*close)(void *, struct z_info *, const char *, struct stat *);
    } c_table[] = {
    #define M_DEFLATE (&c_table[0])
    	{
    		"deflate",
    		".gz",
    		"\037\213",
    		"123456789ab:cdfhkLlNnOo:qrS:tVv",
    		gz_ropen,
    		gz_read,
    #ifndef SMALL
    		gz_wopen,
    		gz_write,
    #endif
    		gz_close
    	},
    #define M_COMPRESS (&c_table[1])
    #ifndef SMALL
    	{
    		"compress",
    		".Z",
    		"\037\235",
    		"123456789ab:cdfghlNnOo:qrS:tv",
    		z_ropen,
    		zread,
    		z_wopen,
    		zwrite,
    		z_close
    	},
    #define M_UNZIP (&c_table[2])
    	{
    		"unzip",
    		".zip",
    		"PK",
    		NULL,
    		zip_ropen,
    		zip_read,
    		NULL,
    		NULL,
    		zip_close
    	},
    #endif /* SMALL */
      { NULL }
    };
    
    #ifndef SMALL
    const struct compressor null_method = {
    	"null",
    	".nul",
    	"XX",
    	"123456789ab:cdfghlNnOo:qrS:tv",
    	null_ropen,
    	null_read,
    	null_wopen,
    	null_write,
    	null_close
    };
    #endif /* SMALL */
    
    static int permission(const char *);
    static __dead void usage(int);
    static int docompress(const char *, char *, const struct compressor *,
        int, struct stat *);
    static int dodecompress(const char *, char *, struct stat *);
    static const char *check_suffix(const char *);
    static char *set_outfile(const char *, char *, size_t);
    static void list_stats(const char *, const struct compressor *,
        struct z_info *);
    static void verbose_info(const char *, off_t, off_t, u_int32_t);
    
    #ifndef SMALL
    const struct option longopts[] = {
    	{ "ascii",	no_argument,		0, 'a' },
    	{ "stdout",	no_argument,		0, 'c' },
    	{ "to-stdout",	no_argument,		0, 'c' },
    	{ "decompress",	no_argument,		0, 'd' },
    	{ "uncompress",	no_argument,		0, 'd' },
    	{ "force",	no_argument,		0, 'f' },
    	{ "help",	no_argument,		0, 'h' },
    	{ "keep",	no_argument,		0, 'k' },
    	{ "list",	no_argument,		0, 'l' },
    	{ "license",	no_argument,		0, 'L' },
    	{ "no-name",	no_argument,		0, 'n' },
    	{ "name",	no_argument,		0, 'N' },
    	{ "quiet",	no_argument,		0, 'q' },
    	{ "recursive",	no_argument,		0, 'r' },
    	{ "suffix",	required_argument,	0, 'S' },
    	{ "test",	no_argument,		0, 't' },
    	{ "verbose",	no_argument,		0, 'v' },
    	{ "version",	no_argument,		0, 'V' },
    	{ "fast",	no_argument,		0, '1' },
    	{ "best",	no_argument,		0, '9' },
    	{ NULL }
    };
    #else /* SMALL */
    const struct option *longopts = NULL;
    #endif /* SMALL */
    
    int
    main(int argc, char *argv[])
    {
    	FTS *ftsp;
    	FTSENT *entry;
    	const struct compressor *method;
    	const char *optstr, *s;
    	char *p, *infile;
    	char outfile[PATH_MAX], _infile[PATH_MAX];
    	int bits, ch, error, rc, cflag, oflag;
    
    	if (pledge("stdio rpath wpath cpath fattr chown", NULL) == -1)
    		err(1, "pledge");
    
    	bits = cflag = oflag = 0;
    	storename = -1;
    	p = __progname;
    	if (p[0] == 'g') {
    		method = M_DEFLATE;
    		bits = 6;
    		p++;
    	} else {
    #ifdef SMALL
    		method = M_DEFLATE;
    #else
    		method = M_COMPRESS;
    #endif /* SMALL */
    	}
    	optstr = method->opts;
    
    	decomp = 0;
    	pmode = MODE_COMP;
    	if (!strcmp(p, "zcat")) {
    		decomp++;
    		cflag = 1;
    		pmode = MODE_CAT;
    	} else {
    		if (p[0] == 'u' && p[1] == 'n') {
    			p += 2;
    			decomp++;
    			pmode = MODE_DECOMP;
    		}
    
    		if (strcmp(p, "zip") &&
    		    strcmp(p, "compress"))
    			errx(1, "unknown program name");
    	}
    
    	strlcpy(suffix, method->suffix, sizeof(suffix));
    
    	if (method == M_DEFLATE && (p = getenv("GZIP")) != NULL) {
    		char *evbuf, *last, **nargv = NULL;
    		int argc_extra = 0, nargc = 0;
    
    		if ((evbuf = strdup(p)) == NULL)
    			err(1, NULL);
    		for ((p = strtok_r(evbuf, " ", &last)); p != NULL;
    		    (p = strtok_r(NULL, " ", &last))) {
    			if (nargc + 1 >= argc_extra) {
    				argc_extra += 1024;
    				nargv = reallocarray(nargv,
    				    argc + argc_extra + 1, sizeof(char *));
    				if (nargv == NULL)
    					err(1, NULL);
    			}
    			nargv[++nargc] = p;
    		}
    		if (nargv != NULL) {
    			nargv[0] = *argv++;
    			while ((nargv[++nargc] = *argv++))
    				;
    			argv = nargv;
    			argc = nargc;
    		}
    	}
    
    	optstr += pmode;
    	while ((ch = getopt_long(argc, argv, optstr, longopts, NULL)) != -1)
    		switch (ch) {
    		case '1':
    		case '2':
    		case '3':
    		case '4':
    		case '5':
    		case '6':
    		case '7':
    		case '8':
    		case '9':
    			method = M_DEFLATE;
    			strlcpy(suffix, method->suffix, sizeof(suffix));
    			bits = ch - '0';
    			break;
    		case 'a':
    			warnx("option -a is ignored on this system");
    			break;
    		case 'b':
    			bits = strtol(optarg, &p, 10);
    			/*
    			 * POSIX 1002.3 says 9 <= bits <= 14 for portable
    			 * apps, but says the implementation may allow
    			 * greater.
    			 */
    			if (*p)
    				errx(1, "illegal bit count -- %s", optarg);
    			break;
    		case 'c':
    			cflag = 1;
    			break;
    		case 'd':		/* Backward compatible. */
    			decomp++;
    			break;
    		case 'f':
    			force++;
    			break;
    		case 'g':
    			method = M_DEFLATE;
    			strlcpy(suffix, method->suffix, sizeof(suffix));
    			bits = 6;
    			break;
    		case 'k':
    			kflag = 1;
    			break;
    		case 'l':
    			list++;
    			testmode = 1;
    			decomp++;
    			break;
    		case 'n':
    			storename = 0;
    			break;
    		case 'N':
    			storename = 1;
    			break;
    #ifndef SMALL
    		case 'O':
    			method = M_COMPRESS;
    			strlcpy(suffix, method->suffix, sizeof(suffix));
    			break;
    #endif /* SMALL */
    		case 'o':
    			if (strlcpy(outfile, optarg,
    			    sizeof(outfile)) >= sizeof(outfile))
    				errx(1, "-o argument is too long");
    			oflag = 1;
    			break;
    		case 'q':
    			verbose = -1;
    			break;
    		case 'S':
    			p = suffix;
    			if (optarg[0] != '.')
    				*p++ = '.';
    			strlcpy(p, optarg, sizeof(suffix) - (p - suffix));
    			break;
    		case 't':
    			testmode = 1;
    			decomp++;
    			break;
    		case 'V':
    			exit (0);
    		case 'v':
    			verbose++;
    			break;
    		case 'L':
    			exit (0);
    		case 'r':
    			recurse++;
    			break;
    
    		case 'h':
    			usage(0);
    			break;
    		default:
    			usage(1);
    		}
    	argc -= optind;
    	argv += optind;
    
    	if (cflag || testmode || (!oflag && argc == 0))
    		if (pledge("stdio rpath", NULL) == -1)
    			err(1, "pledge");
    
    	if (argc == 0) {
    		argv = calloc(2, sizeof(char *));
    		if (argv == NULL)
    			err(1, NULL);
    		argv[0] = "-";
    		argc = 1;
    	}
    	if (oflag && (recurse || argc > 1))
    		errx(1, "-o option may only be used with a single input file");
    
    	if ((cat && argc) + testmode + oflag > 1)
    		errx(1, "may not mix -o, -c, or -t options");
    	/*
    	 * By default, when compressing store the original name and timestamp
    	 * in the header.  Do not restore these when decompressing unless
    	 * the -N option is given.
    	 */
    	if (storename == -1)
    		storename = !decomp;
    
    	if ((ftsp = fts_open(argv, FTS_PHYSICAL|FTS_NOCHDIR, 0)) == NULL)
    		err(1, NULL);
    	for (rc = SUCCESS; (entry = fts_read(ftsp)) != NULL;) {
    		cat = cflag;
    		pipin = 0;
    		infile = entry->fts_path;
    		if (infile[0] == '-' && infile[1] == '\0') {
    			infile = "stdin";
    			pipin++;
    			if (!oflag)
    				cat = 1;
    		}
    		else
    			switch (entry->fts_info) {
    			case FTS_D:
    				if (!recurse) {
    					warnx("%s is a directory: ignored",
    					    infile);
    					fts_set(ftsp, entry, FTS_SKIP);
    				}
    				continue;
    			case FTS_DP:
    				continue;
    			case FTS_NS:
    				/*
    				 * If file does not exist and has no suffix,
    				 * tack on the default suffix and try that.
    				 */
    				if (entry->fts_errno == ENOENT) {
    					p = strrchr(entry->fts_accpath, '.');
    					if ((p == NULL ||
    					    strcmp(p, suffix) != 0) &&
    					    snprintf(_infile, sizeof(_infile),
    					    "%s%s", infile, suffix) <
    					    sizeof(_infile) &&
    					    stat(_infile, entry->fts_statp) ==
    					    0 &&
    					    S_ISREG(entry->fts_statp->st_mode)) {
    						infile = _infile;
    						break;
    					}
    				}
    			case FTS_ERR:
    			case FTS_DNR:
    				warnx("%s: %s", infile,
    				    strerror(entry->fts_errno));
    				rc = rc ? rc : WARNING;
    				continue;
    			default:
    				if (!S_ISREG(entry->fts_statp->st_mode) &&
    				    !(S_ISLNK(entry->fts_statp->st_mode) &&
    				    cat)) {
    					warnx("%s not a regular file%s",
    					    infile, cat ? "" : ": unchanged");
    					rc = rc ? rc : WARNING;
    					continue;
    				}
    				break;
    			}
    
    		if (!decomp && !pipin && (s = check_suffix(infile)) != NULL) {
    			warnx("%s already has %s suffix -- unchanged",
    			    infile, s);
    			rc = rc ? rc : WARNING;
    			continue;
    		}
    
    		if (!oflag) {
    			if (cat)
    				strlcpy(outfile, "stdout", sizeof(outfile));
    			else if (decomp) {
    				if (set_outfile(infile, outfile,
    				    sizeof outfile) == NULL) {
    					if (!recurse) {
    						warnx("%s: unknown suffix: "
    						    "ignored", infile);
    						rc = rc ? rc : WARNING;
    					}
    					continue;
    				}
    			} else {
    				if (snprintf(outfile, sizeof(outfile),
    				    "%s%s", infile, suffix) >= sizeof(outfile)) {
    					warnx("%s%s: name too long",
    					    infile, suffix);
    					rc = rc ? rc : WARNING;
    					continue;
    				}
    			}
    		}
    
    		if (verbose > 0 && !pipin && !list)
    			fprintf(stderr, "%s:\t", infile);
    
    		if (decomp)
    			error = dodecompress(infile, outfile, entry->fts_statp);
    		else
    			error = docompress(infile, outfile, method, bits, entry->fts_statp);
    
    		switch (error) {
    		case SUCCESS:
    			if (!cat && !pipin && !testmode && !kflag) {
    				if (unlink(infile) == -1 && verbose >= 0)
    					warn("input: %s", infile);
    			}
    			break;
    		case WARNING:
    			rc = rc ? rc : WARNING;
    			break;
    		default:
    			rc = FAILURE;
    			break;
    		}
    	}
    	if (list)
    		list_stats(NULL, NULL, NULL);
    	fts_close(ftsp);
    	exit(rc);
    }
    
    static int
    open_input(const char *in)
    {
    	int fd;
    
    	fd = pipin ? dup(STDIN_FILENO) : open(in, O_RDONLY);
    	if (fd == -1) {
    		if (verbose >= 0)
    			warn("%s", in);
    		return -1;
    	}
    	if (decomp && !force && isatty(fd)) {
    		if (verbose >= 0)
    			warnx("%s: won't read compressed data from terminal",
    			    in);
    		close(fd);
    		return -1;
    	}
    
    	return fd;
    }
    
    static int
    open_output(const char *out, int *errorp, int *oreg)
    {
    	struct stat sb;
    	int fd, error = FAILURE;
    
    	if (cat) {
    		fd = dup(STDOUT_FILENO);
    		if (fd == -1)
    			goto bad;
    		sb.st_mode = 0;
    	} else {
    		fd = open(out, O_WRONLY, S_IWUSR);
    		if (fd != -1) {
    			if (fstat(fd, &sb) == -1)
    				goto bad;
    			if (!force && S_ISREG(sb.st_mode) && !permission(out)) {
    				error = WARNING;
    				goto bad;
    			}
    			if (ftruncate(fd, 0) == -1)
    				goto bad;
    		} else {
    			fd = open(out, O_WRONLY|O_CREAT|O_TRUNC, S_IWUSR);
    			if (fd == -1 || fstat(fd, &sb) == -1)
    				goto bad;
    		}
    	}
    
    	*oreg = S_ISREG(sb.st_mode);
    	*errorp = SUCCESS;
    	return fd;
    bad:
    	if (error == FAILURE && verbose >= 0)
    		warn("%s", out);
    	if (fd != -1)
    		close(fd);
    	*errorp = FAILURE;
    	return -1;
    }
    
    static int
    docompress(const char *in, char *out, const struct compressor *method,
        int bits, struct stat *sb)
    {
    #ifndef SMALL
    	u_char buf[Z_BUFSIZE];
    	char namebuf[PATH_MAX];
    	char *name = NULL;
    	int error, ifd, ofd, oreg;
    	void *cookie;
    	ssize_t nr;
    	u_int32_t mtime = 0;
    	struct z_info info;
    
    	ifd = open_input(in);
    	if (ifd == -1)
    		return (FAILURE);
    
    	ofd = open_output(out, &error, &oreg);
    	if (ofd == -1) {
    		close(ifd);
    		return error;
    	}
    
    	if (method != M_COMPRESS && !force && isatty(ofd)) {
    		if (verbose >= 0)
    			warnx("%s: won't write compressed data to terminal",
    			    out);
    		(void) close(ofd);
    		(void) close(ifd);
    		return (FAILURE);
    	}
    
    	if (!pipin && storename) {
    		strlcpy(namebuf, in, sizeof(namebuf));
    		name = basename(namebuf);
    		mtime = (u_int32_t)sb->st_mtime;
    	}
    	if ((cookie = method->wopen(ofd, name, bits, mtime)) == NULL) {
    		if (verbose >= 0)
    			warn("%s", out);
    		if (oreg)
    			(void) unlink(out);
    		(void) close(ofd);
    		(void) close(ifd);
    		return (FAILURE);
    	}
    
    	while ((nr = read(ifd, buf, sizeof(buf))) > 0)
    		if (method->write(cookie, buf, nr) != nr) {
    			if (verbose >= 0)
    				warn("%s", out);
    			error = FAILURE;
    			break;
    		}
    
    	if (!error && nr < 0) {
    		if (verbose >= 0)
    			warn("%s", in);
    		error = FAILURE;
    	}
    
    	if (method->close(cookie, &info, out, sb)) {
    		if (!error && verbose >= 0)
    			warn("%s", out);
    		error = FAILURE;
    	}
    
    	if (close(ifd)) {
    		if (!error && verbose >= 0)
    			warn("%s", in);
    		error = FAILURE;
    	}
    
    	if (!force && !cat && (info.hlen >= info.total_in ||
    	    info.total_out >= info.total_in - info.hlen)) {
    		if (verbose > 0)
    			fprintf(stderr, "file would grow; left unmodified\n");
    		(void) unlink(out);
    		error = WARNING;
    	}
    
    	if (error) {
    		if (oreg)
    			(void) unlink(out);
    	} else if (verbose > 0)
    		verbose_info(out, info.total_out, info.total_in, info.hlen);
    
    	return (error);
    #else
    	warnx("compression not supported");
    	return (FAILURE);
    #endif
    }
    
    static const struct compressor *
    check_method(int fd)
    {
    	const struct compressor *method;
    	u_char magic[2];
    
    	if (read(fd, magic, sizeof(magic)) != 2)
    		return (NULL);
    	for (method = &c_table[0]; method->name != NULL; method++) {
    		if (magic[0] == method->magic[0] &&
    		    magic[1] == method->magic[1])
    			return (method);
    	}
    #ifndef SMALL
    	if (force && cat) {
    		null_magic[0] = magic[0];
    		null_magic[1] = magic[1];
    		return (&null_method);
    	}
    #endif /* SMALL */
    	return (NULL);
    }
    
    static int
    dodecompress(const char *in, char *out, struct stat *sb)
    {
    	const struct compressor *method;
    	u_char buf[Z_BUFSIZE];
    	char oldname[PATH_MAX];
    	int error, oreg, ifd, ofd;
    	void *cookie;
    	ssize_t nr;
    	struct z_info info;
    
    	ifd = open_input(in);
    	if (ifd == -1)
    		return (FAILURE);
    
    	if ((method = check_method(ifd)) == NULL) {
    		if (verbose >= 0)
    			warnx("%s: unrecognized file format", in);
    		close (ifd);
    		return -1;
    	}
    
    	/* XXX - open constrains outfile to PATH_MAX so this is safe */
    	oldname[0] = '\0';
    	if ((cookie = method->ropen(ifd, oldname, 1)) == NULL) {
    		if (verbose >= 0)
    			warn("%s", in);
    		close (ifd);
    		return (FAILURE);
    	}
    	/* Ignore -N when decompressing to stdout. */
    	if (storename && (!cat || list) && oldname[0] != '\0') {
    		const char *oldbase = basename(oldname);
    		char *cp = strrchr(out, '/');
    		if (cp != NULL) {
    			*(cp + 1) = '\0';
    			strlcat(out, oldbase, PATH_MAX);
    		} else
    			strlcpy(out, oldbase, PATH_MAX);
    	}
    
    	if (testmode) {
    		ofd = -1;
    		oreg = 0;
    		error = SUCCESS;
    	} else {
    		ofd = open_output(out, &error, &oreg);
    		if (ofd == -1) {
    			method->close(cookie, NULL, NULL, NULL);
    			return error;
    		}
    	}
    
    	while ((nr = method->read(cookie, buf, sizeof(buf))) > 0) {
    		if (ofd != -1 && write(ofd, buf, nr) != nr) {
    			if (verbose >= 0)
    				warn("%s", out);
    			error = FAILURE;
    			break;
    		}
    	}
    
    	if (!error && nr < 0) {
    		if (verbose >= 0)
    			warnx("%s: %s", in,
    			    errno == EINVAL ? "crc error" : strerror(errno));
    		error = errno == EINVAL ? WARNING : FAILURE;
    	}
    
    	if (method->close(cookie, &info, NULL, NULL) && !error) {
    #ifdef M_UNZIP
    		if (errno == EEXIST) {
    			if (verbose >= 0) {
    				warnx("more than one entry in %s: %s", in,
    				    cat ? "ignoring the rest" : "unchanged");
    			}
    			error = cat ? WARNING : FAILURE;
    		} else
    #endif
    		{
    			if (verbose >= 0)
    				warn("%s", in);
    			error = FAILURE;
    		}
    	}
    	if (storename && !cat) {
    		if (info.mtime != 0) {
    			sb->st_mtim.tv_sec = sb->st_atim.tv_sec = info.mtime;
    			sb->st_mtim.tv_nsec = sb->st_atim.tv_nsec = 0;
    		}
    	}
    	if (error != FAILURE)
    		setfile(out, ofd, sb);
    
    	if (ofd != -1 && close(ofd)) {
    		if (!error && verbose >= 0)
    			warn("%s", out);
    		error = FAILURE;
    	}
    
    	if (error != FAILURE) {
    		if (list) {
    			if (info.mtime == 0)
    				info.mtime = (u_int32_t)sb->st_mtime;
    			list_stats(out, method, &info);
    		} else if (verbose > 0) {
    			verbose_info(out, info.total_in, info.total_out,
    			    info.hlen);
    		}
    	}
    
    	/* On error, clean up the file we created but preserve errno. */
    	if (error == FAILURE && oreg)
    		unlink(out);
    
    	return (error);
    }
    
    void
    setfile(const char *name, int fd, struct stat *fs)
    {
    	struct timespec ts[2];
    
    	if (name == NULL || cat || testmode)
    		return;
    
    	/*
    	 * If input was a pipe we don't have any info to restore but we
    	 * must set the mode since the current mode on the file is 0200.
    	 */
    	if (pipin) {
    		mode_t mask = umask(022);
    		fchmod(fd, DEFFILEMODE & ~mask);
    		umask(mask);
    		return;
    	}
    
    	/*
    	 * Changing the ownership probably won't succeed, unless we're root
    	 * or POSIX_CHOWN_RESTRICTED is not set.  Set uid/gid bits are not
    	 * allowed.
    	 */
    	fs->st_mode &= ACCESSPERMS;
    	if (fchown(fd, fs->st_uid, fs->st_gid)) {
    		if (errno != EPERM)
    			warn("fchown: %s", name);
    		fs->st_mode &= ~(S_ISUID|S_ISGID);
    	}
    	if (fchmod(fd, fs->st_mode))
    		warn("fchmod: %s", name);
    
    	if (fs->st_flags && fchflags(fd, fs->st_flags))
    		warn("fchflags: %s", name);
    
    	ts[0] = fs->st_atim;
    	ts[1] = fs->st_mtim;
    	if (futimens(fd, ts))
    		warn("futimens: %s", name);
    }
    
    static int
    permission(const char *fname)
    {
    	int ch, first;
    
    	if (!isatty(fileno(stderr)))
    		return (0);
    	(void)fprintf(stderr, "overwrite %s? ", fname);
    	first = ch = getchar();
    	while (ch != '\n' && ch != EOF)
    		ch = getchar();
    	return (first == 'y');
    }
    
    /*
     * Check infile for a known suffix and return the suffix portion or NULL.
     */
    static const char *
    check_suffix(const char *infile)
    {
    	int i;
    	const char *suf, *sep;
    	const char separators[] = ".-_";
    	const char *suffixes[] = { "Z", "gz", "z", "tgz", "taz", NULL };
    
    	for (sep = separators; *sep != '\0'; sep++) {
    		if ((suf = strrchr(infile, *sep)) == NULL)
    			continue;
    		suf++;
    
    		if (strcmp(suf, suffix + 1) == 0)
    			return (suf - 1);
    		for (i = 0; suffixes[i] != NULL; i++) {
    			if (strcmp(suf, suffixes[i]) == 0)
    				return (suf - 1);
    		}
    	}
    	return (NULL);
    }
    
    /*
     * Set outfile based on the suffix.  In most cases we just strip
     * off the suffix but things like .tgz and .taz are special.
     */
    static char *
    set_outfile(const char *infile, char *outfile, size_t osize)
    {
    	const char *s;
    	char *cp;
    
    	if ((s = check_suffix(infile)) == NULL)
    		return (NULL);
    
    	(void)strlcpy(outfile, infile, osize);
    	cp = outfile + (s - infile) + 1;
    	/*
    	 * Convert tgz and taz -> tar, else drop the suffix.
    	 */
    	if (strcmp(cp, "tgz") == 0) {
    		cp[1] = 'a';
    		cp[2] = 'r';
    	} else if (strcmp(cp, "taz") == 0)
    		cp[2] = 'r';
    	else
    		cp[-1] = '\0';
    	return (outfile);
    }
    
    /*
     * Print output for the -l option.
     */
    static void
    list_stats(const char *name, const struct compressor *method,
        struct z_info *info)
    {
    	static off_t compressed_total, uncompressed_total, header_total;
    	static u_int nruns;
    	char *timestr;
    
    	if (nruns == 0) {
    		if (verbose >= 0) {
    			if (verbose > 0)
    				fputs("method  crc      date   time  ", stdout);
    			puts("compressed  uncompressed  ratio  uncompressed_name");
    		}
    	}
    	nruns++;
    
    	if (name != NULL) {
    		if (verbose > 0) {
    			time_t t = info->mtime;		/* XXX 32 bit mtime */
    
    			timestr = ctime(&t) + 4;
    			timestr[12] = '\0';
    			if (timestr[4] == ' ')
    				timestr[4] = '0';
    			printf("%-7.7s %08x %s ", method->name, info->crc,
    			    timestr);
    		}
    		printf("%10lld    %10lld  %4.1f%%  %s\n",
    		    (long long)(info->total_in + info->hlen),
    		    (long long)info->total_out,
    		    ((long long)info->total_out - (long long)info->total_in) *
    		    100.0 / info->total_out, name);
    		compressed_total += info->total_in;
    		uncompressed_total += info->total_out;
    		header_total += info->hlen;
    	} else if (verbose >= 0) {
    		if (nruns < 3)		/* only do totals for > 1 files */
    			return;
    		if (verbose > 0)
    			fputs("                              ", stdout);
    		printf("%10lld    %10lld  %4.1f%%  (totals)\n",
    		    (long long)(compressed_total + header_total),
    		    (long long)uncompressed_total,
    		    (uncompressed_total - compressed_total) *
    		    100.0 / uncompressed_total);
    	}
    }
    
    static void
    verbose_info(const char *file, off_t compressed, off_t uncompressed,
        u_int32_t hlen)
    {
    	if (testmode) {
    		fputs("OK\n", stderr);
    		return;
    	}
    	if (!pipin) {
    		fprintf(stderr, "\t%4.1f%% -- %s %s\n",
    		    (uncompressed - compressed) * 100.0 / uncompressed,
    		    kflag ? "created" : "replaced with", file);
    	}
    	compressed += hlen;
    	fprintf(stderr, "%lld bytes in, %lld bytes out\n",
    	    (long long)(decomp ? compressed : uncompressed),
    	    (long long)(decomp ? uncompressed : compressed));
    }
    
    static __dead void
    usage(int status)
    {
    	const bool gzip = (__progname[0] == 'g');
    
    	switch (pmode) {
    	case MODE_COMP:
    		fprintf(stderr, "usage: %s [-123456789cdf%sh%slNnOqrt%sv] "
    		    "[-b bits] [-o filename] [-S suffix]\n"
    		    "       %*s [file ...]\n", __progname,
    		    !gzip ? "g" : "", gzip ? "kL" : "", gzip ? "V" : "",
    		    (int)strlen(__progname), "");
    		break;
    	case MODE_DECOMP:
    		fprintf(stderr, "usage: %s [-cfh%slNnqrt%sv] [-o filename] "
    		    "[file ...]\n", __progname,
    		    gzip ? "kL" : "", gzip ? "V" : "");
    		break;
    	case MODE_CAT:
    		fprintf(stderr, "usage: %s [-f%shqr] [file ...]\n",
    		    __progname, gzip ? "" : "g");
    		break;
    	}
    	exit(status);
    }