hush/archival/gunzip.c
Denis Vlasenko 22dca23d52 archival: added O_TRUNC so that when we overwrite files on unpack,
we truncate them. Also spotted & fixed hard to trigger bug
          with extension handling.
2006-09-03 14:23:29 +00:00

154 lines
4.1 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Gzip implementation for busybox
*
* Based on GNU gzip v1.2.4 Copyright (C) 1992-1993 Jean-loup Gailly.
*
* Originally adjusted for busybox by Sven Rudolph <sr1@inf.tu-dresden.de>
* based on gzip sources
*
* Adjusted further by Erik Andersen <andersen@codepoet.org> to support files as
* well as stdin/stdout, and to generally behave itself wrt command line
* handling.
*
* General cleanup to better adhere to the style guide and make use of standard
* busybox functions by Glenn McGrath <bug1@iinet.net.au>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*
* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
* Copyright (C) 1992-1993 Jean-loup Gailly
* The unzip code was written and put in the public domain by Mark Adler.
* Portions of the lzw code are derived from the public domain 'compress'
* written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
* Ken Turkowski, Dave Mack and Peter Jannesen.
*
* See the license_msg below and the file COPYING for the software license.
* See the file algorithm.doc for the compression algorithms and file formats.
*/
#include "busybox.h"
#include "unarchive.h"
#define GUNZIP_OPT_STDOUT 1
#define GUNZIP_OPT_FORCE 2
#define GUNZIP_OPT_TEST 4
#define GUNZIP_OPT_DECOMPRESS 8
int gunzip_main(int argc, char **argv)
{
char status = EXIT_SUCCESS;
unsigned long opt;
opt = bb_getopt_ulflags(argc, argv, "cftd");
/* if called as zcat */
if (strcmp(bb_applet_name, "zcat") == 0) {
opt |= GUNZIP_OPT_STDOUT;
}
do {
struct stat stat_buf;
const char *old_path = argv[optind];
const char *delete_path = NULL;
char *new_path = NULL;
int src_fd;
int dst_fd;
optind++;
if (old_path == NULL || strcmp(old_path, "-") == 0) {
src_fd = STDIN_FILENO;
opt |= GUNZIP_OPT_STDOUT;
} else {
src_fd = xopen(old_path, O_RDONLY);
/* Get the time stamp on the input file. */
xstat(old_path, &stat_buf);
}
/* Check that the input is sane. */
if (isatty(src_fd) && ((opt & GUNZIP_OPT_FORCE) == 0)) {
bb_error_msg_and_die
("compressed data not read from terminal. Use -f to force it.");
}
/* Set output filename and number */
if (opt & GUNZIP_OPT_TEST) {
dst_fd = xopen(bb_dev_null, O_WRONLY); /* why does test use filenum 2 ? */
} else if (opt & GUNZIP_OPT_STDOUT) {
dst_fd = STDOUT_FILENO;
} else {
char *extension;
new_path = xstrdup(old_path);
extension = strrchr(new_path, '.');
#ifdef CONFIG_FEATURE_GUNZIP_UNCOMPRESS
if (extension && (strcmp(extension, ".Z") == 0)) {
*extension = '\0';
} else
#endif
if (extension && (strcmp(extension, ".gz") == 0)) {
*extension = '\0';
} else if (extension && (strcmp(extension, ".tgz") == 0)) {
extension[2] = 'a';
extension[3] = 'r';
} else {
bb_error_msg_and_die("Invalid extension");
}
/* Open output file (with correct permissions) */
dst_fd = xopen3(new_path, O_WRONLY | O_CREAT | O_TRUNC,
stat_buf.st_mode);
/* If unzip succeeds remove the old file */
delete_path = old_path;
}
/* do the decompression, and cleanup */
if (xread_char(src_fd) == 0x1f) {
unsigned char magic2;
magic2 = xread_char(src_fd);
#ifdef CONFIG_FEATURE_GUNZIP_UNCOMPRESS
if (magic2 == 0x9d) {
status = uncompress(src_fd, dst_fd);
} else
#endif
if (magic2 == 0x8b) {
check_header_gzip(src_fd);
status = inflate_gunzip(src_fd, dst_fd);
if (status != 0) {
bb_error_msg_and_die("Error inflating");
}
} else {
bb_error_msg_and_die("Invalid magic");
}
} else {
bb_error_msg_and_die("Invalid magic");
}
if ((status != EXIT_SUCCESS) && (new_path)) {
/* Unzip failed, remove new path instead of old path */
delete_path = new_path;
}
if (dst_fd != STDOUT_FILENO) {
close(dst_fd);
}
if (src_fd != STDIN_FILENO) {
close(src_fd);
}
/* delete_path will be NULL if in test mode or from stdin */
if (delete_path && (unlink(delete_path) == -1)) {
bb_error_msg_and_die("Couldn't remove %s", delete_path);
}
free(new_path);
} while (optind < argc);
return status;
}