tar.c

手机嵌入式Linux下可用的busybox源码

/* vi: set sw=4 ts=4: */
/*
 * Mini tar implementation for busybox 
 *
 * Note, that as of BusyBox-0.43, tar has been completely rewritten from the
 * ground up.  It still has remnents of the old code lying about, but it is
 * very different now (i.e., cleaner, less global variables, etc.)
 *
 * Copyright (C) 1999,2000 by Lineo, inc. and Erik Andersen
 * Copyright (C) 1999-2002 by Erik Andersen <[e-mail]>
 *
 * Based in part in the tar implementation in sash
 *  Copyright (c) 1999 by David I. Bell
 *  Permission is granted to use, distribute, or modify this source,
 *  provided that this copyright notice remains intact.
 *  Permission to distribute sash derived code under the GPL has been granted.
 *
 * Based in part on the tar implementation from busybox-0.28
 *  Copyright (C) 1995 Bruce Perens
 *  This is free software under the GNU General Public License.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */


#include <stdio.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <time.h>
#include <utime.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <getopt.h>
#include <fnmatch.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include "busybox.h"

/* Tar file constants  */
#ifndef MAJOR
#define MAJOR(dev) (((dev)>>8)&0xff)
#define MINOR(dev) ((dev)&0xff)
#endif

enum { NAME_SIZE = 100 }; /* because gcc won't let me use 'static const int' */

/* POSIX tar Header Block, from POSIX 1003.1-1990  */
struct TarHeader
{
                                /* byte offset */
	char name[NAME_SIZE];         /*   0-99 */
	char mode[8];                 /* 100-107 */
	char uid[8];                  /* 108-115 */
	char gid[8];                  /* 116-123 */
	char size[12];                /* 124-135 */
	char mtime[12];               /* 136-147 */
	char chksum[8];               /* 148-155 */
	char typeflag;                /* 156-156 */
	char linkname[NAME_SIZE];     /* 157-256 */
	char magic[6];                /* 257-262 */
	char version[2];              /* 263-264 */
	char uname[32];               /* 265-296 */
	char gname[32];               /* 297-328 */
	char devmajor[8];             /* 329-336 */
	char devminor[8];             /* 337-344 */
	char prefix[155];             /* 345-499 */
	char padding[12];             /* 500-512 (pad to exactly the TAR_BLOCK_SIZE) */
};
typedef struct TarHeader TarHeader;


/* A few useful constants */
#define TAR_MAGIC          "ustar"        /* ustar and a null */
#define TAR_VERSION        "  "           /* Be compatable with GNU tar format */
static const int TAR_MAGIC_LEN = 6;
static const int TAR_VERSION_LEN = 2;
static const int TAR_BLOCK_SIZE = 512;

/* A nice enum with all the possible tar file content types */
enum TarFileType 
{
	REGTYPE  = '0',            /* regular file */
	REGTYPE0 = '\0',           /* regular file (ancient bug compat)*/
	LNKTYPE  = '1',            /* hard link */
	SYMTYPE  = '2',            /* symbolic link */
	CHRTYPE  = '3',            /* character special */
	BLKTYPE  = '4',            /* block special */
	DIRTYPE  = '5',            /* directory */
	FIFOTYPE = '6',            /* FIFO special */
	CONTTYPE = '7',            /* reserved */
	GNULONGLINK = 'K',         /* GNU long (>100 chars) link name */
	GNULONGNAME = 'L',         /* GNU long (>100 chars) file name */
};
typedef enum TarFileType TarFileType;

/* This struct ignores magic, non-numeric user name, 
 * non-numeric group name, and the checksum, since
 * these are all ignored by BusyBox tar. */ 
struct TarInfo
{
	int              tarFd;          /* An open file descriptor for reading from the tarball */
	char *           name;           /* File name */
	mode_t           mode;           /* Unix mode, including device bits. */
	uid_t            uid;            /* Numeric UID */
	gid_t            gid;            /* Numeric GID */
	size_t           size;           /* Size of file */
	time_t           mtime;          /* Last-modified time */
	enum TarFileType type;           /* Regular, directory, link, etc. */
	char *           linkname;       /* Name for symbolic and hard links */
	long             devmajor;       /* Major number for special device */
	long             devminor;       /* Minor number for special device */
};
typedef struct TarInfo TarInfo;

/* Local procedures to restore files from a tar file.  */
static int readTarFile(int tarFd, int extractFlag, int listFlag, 
		int tostdoutFlag, int verboseFlag, char** extractList,
		char** excludeList);

#ifdef BB_FEATURE_TAR_CREATE
/* Local procedures to save files into a tar file.  */
static int writeTarFile(const char* tarName, int verboseFlag, char **argv,
		char** excludeList);
#endif

#if defined BB_FEATURE_TAR_EXCLUDE
static struct option longopts[] = {
	{ "exclude", 1, NULL, 'e' },
	{ NULL, 0, NULL, 0 }
};
#endif

extern int tar_main(int argc, char **argv)
{
	char** excludeList=NULL;
	char** extractList=NULL;
	const char *tarName="-";
	const char *cwd=NULL;
#if defined BB_FEATURE_TAR_EXCLUDE
	int excludeListSize=0;
	FILE *fileList;
	char file[256];
#endif
#if defined BB_FEATURE_TAR_GZIP
	FILE *comp_file = NULL;
	int unzipFlag    = FALSE;
#endif
	int listFlag     = FALSE;
	int extractFlag  = FALSE;
	int createFlag   = FALSE;
	int verboseFlag  = FALSE;
	int tostdoutFlag = FALSE;
	int status       = FALSE;
	int opt;
#if defined BB_FEATURE_TAR_GZIP
	pid_t pid;
#endif

	if (argc <= 1)
		show_usage();

	if (argv[1][0] != '-') {
		char *tmp = xmalloc(strlen(argv[1]) + 2);
		tmp[0] = '-';
		strcpy(tmp + 1, argv[1]);
		argv[1] = tmp;
	}

	while (
#ifndef BB_FEATURE_TAR_EXCLUDE
			(opt = getopt(argc, argv, "cxtzvOf:pC:"))
#else
			(opt = getopt_long(argc, argv, "cxtzvOf:X:pC:", longopts, NULL))
#endif
			> 0) {
		switch (opt) {
			case 'c':
				if (extractFlag == TRUE || listFlag == TRUE)
					goto flagError;
				createFlag = TRUE;
				break;
			case 'x':
				if (listFlag == TRUE || createFlag == TRUE)
					goto flagError;
				extractFlag = TRUE;
				break;
			case 't':
				if (extractFlag == TRUE || createFlag == TRUE)
					goto flagError;
				listFlag = TRUE;
				break;
#ifdef BB_FEATURE_TAR_GZIP
			case 'z':
				unzipFlag = TRUE;
				break;
#endif
			case 'v':
				verboseFlag = TRUE;
				break;
			case 'O':
				tostdoutFlag = TRUE;
				break;
			case 'f':
				if (*tarName != '-')
					error_msg_and_die( "Only one 'f' option allowed");
				tarName = optarg;
				break;
#if defined BB_FEATURE_TAR_EXCLUDE
			case 'e':
				excludeList=xrealloc( excludeList,
						sizeof(char *) * (excludeListSize+2));
				excludeList[excludeListSize] = optarg;
				/* Tack a NULL onto the end of the list */
				excludeList[++excludeListSize] = NULL;
			case 'X':
				fileList = xfopen(optarg, "r");
				while (fgets(file, sizeof(file), fileList) != NULL) {
					excludeList = xrealloc(excludeList,
							sizeof(char *) * (excludeListSize+2));
					chomp(file);
					excludeList[excludeListSize] = xstrdup(file);
					/* Tack a NULL onto the end of the list */
					excludeList[++excludeListSize] = NULL;
				}
				fclose(fileList);
				break;
#endif
			case 'p':
				break;
			case 'C':
				cwd = xgetcwd((char *)cwd);
				if (chdir(optarg)) {
					printf("cd: %s: %s\n", optarg, strerror(errno));
					return EXIT_FAILURE;
				}
				break;
			default:
					show_usage();
		}
	}

	/*
	 * Do the correct type of action supplying the rest of the
	 * command line arguments as the list of files to process.
	 */
	if (createFlag == TRUE) {
#ifndef BB_FEATURE_TAR_CREATE
		error_msg_and_die( "This version of tar was not compiled with tar creation support.");
#else
#ifdef BB_FEATURE_TAR_GZIP
		if (unzipFlag==TRUE)
			error_msg_and_die("Creation of compressed not internally support by tar, pipe to busybox gunzip");
#endif
		status = writeTarFile(tarName, verboseFlag, argv + optind, excludeList);
#endif
	}
	if (listFlag == TRUE || extractFlag == TRUE) {
		int tarFd;
		if (argv[optind])
			extractList = argv + optind;
		/* Open the tar file for reading.  */
		if (!strcmp(tarName, "-"))
			tarFd = fileno(stdin);
		else
			tarFd = open(tarName, O_RDONLY);
		if (tarFd < 0)
			perror_msg_and_die("Error opening '%s'", tarName);

#ifdef BB_FEATURE_TAR_GZIP	
		/* unzip tarFd in a seperate process */
		if (unzipFlag == TRUE) {
			comp_file = fdopen(tarFd, "r");

			/* set the buffer size */
			setvbuf(comp_file, NULL, _IOFBF, 0x8000);

			if ((tarFd = fileno(gz_open(comp_file, &pid))) == EXIT_FAILURE) {
				error_msg_and_die("Couldnt unzip file");
			}
		}
#endif			
		status = readTarFile(tarFd, extractFlag, listFlag, tostdoutFlag,
					verboseFlag, extractList, excludeList);
		close(tarFd);
#ifdef BB_FEATURE_TAR_GZIP	
		if (unzipFlag == TRUE) {
			gz_close(pid);
			fclose(comp_file);
		}
#endif			
	}

	if (cwd)
		chdir(cwd);
	if (status == TRUE)
		return EXIT_SUCCESS;
	else
		return EXIT_FAILURE;

  flagError:
	error_msg_and_die( "Exactly one of 'c', 'x' or 't' must be specified");
}
					
static void
fixUpPermissions(TarInfo *header)
{
	struct utimbuf t;
	/* Now set permissions etc. for the new file */
	chown(header->name, header->uid, header->gid);
	chmod(header->name, header->mode);
	/* Reset the time */
	t.actime = time(0);
	t.modtime = header->mtime;
	utime(header->name, &t);
}
				
static int
tarExtractRegularFile(TarInfo *header, int extractFlag, int tostdoutFlag)
{
	size_t  writeSize;
	size_t  readSize;
	size_t  actualWriteSz;
	char    buffer[20 * TAR_BLOCK_SIZE];
	size_t  size = header->size;
	int outFd=fileno(stdout);

	/* Open the file to be written, if a file is supposed to be written */
	if (extractFlag==TRUE && tostdoutFlag==FALSE) {
		/* Create the path to the file, just in case it isn't there...
		 * This should not screw up path permissions or anything. */
		char *buf, *dir;
		buf = xstrdup (header->name);
		dir = dirname (buf);
		make_directory (dir, -1, FILEUTILS_RECUR);
		free (buf);
		if ((outFd=open(header->name, O_CREAT|O_TRUNC|O_WRONLY, 
						header->mode & ~S_IFMT)) < 0) {
			error_msg(io_error, header->name, strerror(errno)); 
			return( FALSE);
		}
	}

	/* Write out the file, if we are supposed to be doing that */
	while ( size > 0 ) {
		actualWriteSz=0;
		if ( size > sizeof(buffer) )
			writeSize = readSize = sizeof(buffer);
		else {
			int mod = size % TAR_BLOCK_SIZE;
			if ( mod != 0 )
				readSize = size + (TAR_BLOCK_SIZE - mod);
			else
				readSize = size;
			writeSize = size;
		}
		if ( (readSize = full_read(header->tarFd, buffer, readSize)) <= 0 ) {
			/* Tarball seems to have a problem */
			error_msg("Unexpected EOF in archive"); 
			return( FALSE);
		}
		if ( readSize < writeSize )
			writeSize = readSize;

		/* Write out the file, if we are supposed to be doing that */
		if (extractFlag==TRUE) {

			if ((actualWriteSz=full_write(outFd, buffer, writeSize)) != writeSize ) {
				/* Output file seems to have a problem */
				error_msg(io_error, header->name, strerror(errno));