tar.c

手机嵌入式Linux下可用的busybox源码

		if (errorFlag==TRUE)
			error_msg( "Error exit delayed from previous errors");
		else
			return( TRUE);
	} 
	return( FALSE);
}


#ifdef BB_FEATURE_TAR_CREATE

/*
** writeTarFile(),  writeFileToTarball(), and writeTarHeader() are
** the only functions that deal with the HardLinkInfo structure.
** Even these functions use the xxxHardLinkInfo() functions.
*/
typedef struct HardLinkInfo HardLinkInfo;
struct HardLinkInfo
{
	HardLinkInfo *next;           /* Next entry in list */
	dev_t dev;                    /* Device number */
	ino_t ino;                    /* Inode number */
	short linkCount;              /* (Hard) Link Count */
	char name[1];                 /* Start of filename (must be last) */
};

/* Some info to be carried along when creating a new tarball */
struct TarBallInfo
{
	char* fileName;               /* File name of the tarball */
	int tarFd;                    /* Open-for-write file descriptor
									 for the tarball */
	struct stat statBuf;          /* Stat info for the tarball, letting
									 us know the inode and device that the
									 tarball lives, so we can avoid trying 
									 to include the tarball into itself */
	int verboseFlag;              /* Whether to print extra stuff or not */
	char** excludeList;           /* List of files to not include */
	HardLinkInfo *hlInfoHead;     /* Hard Link Tracking Information */
	HardLinkInfo *hlInfo;         /* Hard Link Info for the current file */
};
typedef struct TarBallInfo TarBallInfo;


/* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
static void
addHardLinkInfo (HardLinkInfo **hlInfoHeadPtr, dev_t dev, ino_t ino,
		short linkCount, const char *name)
{
	/* Note: hlInfoHeadPtr can never be NULL! */
	HardLinkInfo *hlInfo;

	hlInfo = (HardLinkInfo *)xmalloc(sizeof(HardLinkInfo)+strlen(name)+1);
	if (hlInfo) {
		hlInfo->next = *hlInfoHeadPtr;
		*hlInfoHeadPtr = hlInfo;
		hlInfo->dev = dev;
		hlInfo->ino = ino;
		hlInfo->linkCount = linkCount;
		strcpy(hlInfo->name, name);
	}
	return;
}

static void
freeHardLinkInfo (HardLinkInfo **hlInfoHeadPtr)
{
	HardLinkInfo *hlInfo = NULL;
	HardLinkInfo *hlInfoNext = NULL;

	if (hlInfoHeadPtr) {
		hlInfo = *hlInfoHeadPtr;
		while (hlInfo) {
			hlInfoNext = hlInfo->next;
			free(hlInfo);
			hlInfo = hlInfoNext;
		}
		*hlInfoHeadPtr = NULL;
	}
	return;
}

/* Might be faster (and bigger) if the dev/ino were stored in numeric order;) */
static HardLinkInfo *
findHardLinkInfo (HardLinkInfo *hlInfo, dev_t dev, ino_t ino)
{
	while(hlInfo) {
		if ((ino == hlInfo->ino) && (dev == hlInfo->dev))
			break;
		hlInfo = hlInfo->next;
	}
	return(hlInfo);
}

/* Put an octal string into the specified buffer.
 * The number is zero and space padded and possibly null padded.
 * Returns TRUE if successful.  */ 
static int putOctal (char *cp, int len, long value)
{
	int tempLength;
	char tempBuffer[32];
	char *tempString = tempBuffer;

	/* Create a string of the specified length with an initial space,
	 * leading zeroes and the octal number, and a trailing null.  */
	sprintf (tempString, "%0*lo", len - 1, value);

	/* If the string is too large, suppress the leading space.  */
	tempLength = strlen (tempString) + 1;
	if (tempLength > len) {
		tempLength--;
		tempString++;
	}

	/* If the string is still too large, suppress the trailing null.  */
	if (tempLength > len)
		tempLength--;

	/* If the string is still too large, fail.  */
	if (tempLength > len)
		return FALSE;

	/* Copy the string to the field.  */
	memcpy (cp, tempString, len);

	return TRUE;
}

/* Write out a tar header for the specified file/directory/whatever */
static int
writeTarHeader(struct TarBallInfo *tbInfo, const char *header_name,
		const char *real_name, struct stat *statbuf)
{
	long chksum=0;
	struct TarHeader header;
	const unsigned char *cp = (const unsigned char *) &header;
	ssize_t size = sizeof(struct TarHeader);
		
	memset( &header, 0, size);

	strncpy(header.name, header_name, sizeof(header.name)); 

	putOctal(header.mode, sizeof(header.mode), statbuf->st_mode);
	putOctal(header.uid, sizeof(header.uid), statbuf->st_uid);
	putOctal(header.gid, sizeof(header.gid), statbuf->st_gid);
	putOctal(header.size, sizeof(header.size), 0); /* Regular file size is handled later */
	putOctal(header.mtime, sizeof(header.mtime), statbuf->st_mtime);
	strncpy(header.magic, TAR_MAGIC TAR_VERSION, 
			TAR_MAGIC_LEN + TAR_VERSION_LEN );

	/* Enter the user and group names (default to root if it fails) */
	my_getpwuid(header.uname, statbuf->st_uid);
	if (! *header.uname)
		strcpy(header.uname, "root");
	my_getgrgid(header.gname, statbuf->st_gid);
	if (! *header.uname)
		strcpy(header.uname, "root");

	if (tbInfo->hlInfo) {
		/* This is a hard link */
		header.typeflag = LNKTYPE;
		strncpy(header.linkname, tbInfo->hlInfo->name, sizeof(header.linkname));
	} else if (S_ISLNK(statbuf->st_mode)) {
		char *lpath = xreadlink(real_name);
		if (!lpath) /* Already printed err msg inside xreadlink() */
			return ( FALSE);
		header.typeflag  = SYMTYPE;
		strncpy(header.linkname, lpath, sizeof(header.linkname)); 
		free(lpath);
	} else if (S_ISDIR(statbuf->st_mode)) {
		header.typeflag  = DIRTYPE;
		strncat(header.name, "/", sizeof(header.name)); 
	} else if (S_ISCHR(statbuf->st_mode)) {
		header.typeflag  = CHRTYPE;
		putOctal(header.devmajor, sizeof(header.devmajor), MAJOR(statbuf->st_rdev));
		putOctal(header.devminor, sizeof(header.devminor), MINOR(statbuf->st_rdev));
	} else if (S_ISBLK(statbuf->st_mode)) {
		header.typeflag  = BLKTYPE;
		putOctal(header.devmajor, sizeof(header.devmajor), MAJOR(statbuf->st_rdev));
		putOctal(header.devminor, sizeof(header.devminor), MINOR(statbuf->st_rdev));
	} else if (S_ISFIFO(statbuf->st_mode)) {
		header.typeflag  = FIFOTYPE;
	} else if (S_ISREG(statbuf->st_mode)) {
		header.typeflag  = REGTYPE;
		putOctal(header.size, sizeof(header.size), statbuf->st_size);
	} else {
		error_msg("%s: Unknown file type", real_name);
		return ( FALSE);
	}

	/* Calculate and store the checksum (i.e., the sum of all of the bytes of
	 * the header).  The checksum field must be filled with blanks for the
	 * calculation.  The checksum field is formatted differently from the
	 * other fields: it has [6] digits, a null, then a space -- rather than
	 * digits, followed by a null like the other fields... */
	memset(header.chksum, ' ', sizeof(header.chksum));
	cp = (const unsigned char *) &header;
	while (size-- > 0)
		chksum += *cp++;
	putOctal(header.chksum, 7, chksum);
	
	/* Now write the header out to disk */
	if ((size=full_write(tbInfo->tarFd, (char*)&header, sizeof(struct TarHeader))) < 0) {
		error_msg(io_error, real_name, strerror(errno)); 
		return ( FALSE);
	}
	/* Pad the header up to the tar block size */
	for (; size<TAR_BLOCK_SIZE; size++) {
		write(tbInfo->tarFd, "\0", 1);
	}
	/* Now do the verbose thing (or not) */
	if (tbInfo->verboseFlag==TRUE) {
		FILE *vbFd = stdout;
		if (tbInfo->tarFd == fileno(stdout))	// If the archive goes to stdout, verbose to stderr
			vbFd = stderr;
		fprintf(vbFd, "%s\n", header.name);
	}

	return ( TRUE);
}


static int writeFileToTarball(const char *fileName, struct stat *statbuf, void* userData)
{
	struct TarBallInfo *tbInfo = (struct TarBallInfo *)userData;
	const char *header_name;

	/*
	** Check to see if we are dealing with a hard link.
	** If so -
	** Treat the first occurance of a given dev/inode as a file while
	** treating any additional occurances as hard links.  This is done
	** by adding the file information to the HardLinkInfo linked list.
	*/
	tbInfo->hlInfo = NULL;
	if (statbuf->st_nlink > 1) {
		tbInfo->hlInfo = findHardLinkInfo(tbInfo->hlInfoHead, statbuf->st_dev, 
				statbuf->st_ino);
		if (tbInfo->hlInfo == NULL)
			addHardLinkInfo (&tbInfo->hlInfoHead, statbuf->st_dev,
					statbuf->st_ino, statbuf->st_nlink, fileName);
	}

	/* It is against the rules to archive a socket */
	if (S_ISSOCK(statbuf->st_mode)) {
		error_msg("%s: socket ignored", fileName);
		return( TRUE);
	}

	/* It is a bad idea to store the archive we are in the process of creating,
	 * so check the device and inode to be sure that this particular file isn't
	 * the new tarball */
	if (tbInfo->statBuf.st_dev == statbuf->st_dev &&
			tbInfo->statBuf.st_ino == statbuf->st_ino) {
		error_msg("%s: file is the archive; skipping", fileName);
		return( TRUE);
	}

	header_name = fileName;
	while (header_name[0] == '/') {
		static int alreadyWarned=FALSE;
		if (alreadyWarned==FALSE) {
			error_msg("Removing leading '/' from member names");
			alreadyWarned=TRUE;
		}
		header_name++;
	}

	if (strlen(fileName) >= NAME_SIZE) {
		error_msg(name_longer_than_foo, NAME_SIZE);
		return ( TRUE);
	}

	if (header_name[0] == '\0')
		return TRUE;

#if defined BB_FEATURE_TAR_EXCLUDE
	if (exclude_file(tbInfo->excludeList, header_name)) {
		return SKIP;
	}
#endif

	if (writeTarHeader(tbInfo, header_name, fileName, statbuf)==FALSE) {
		return( FALSE);
	} 

	/* Now, if the file is a regular file, copy it out to the tarball */
	if ((tbInfo->hlInfo == NULL)
	&&  (S_ISREG(statbuf->st_mode))) {
		int  inputFileFd;
		char buffer[BUFSIZ];
		ssize_t size=0, readSize=0;

		/* open the file we want to archive, and make sure all is well */
		if ((inputFileFd = open(fileName, O_RDONLY)) < 0) {
			error_msg("%s: Cannot open: %s", fileName, strerror(errno));
			return( FALSE);
		}
		
		/* write the file to the archive */
		while ( (size = full_read(inputFileFd, buffer, sizeof(buffer))) > 0 ) {
			if (full_write(tbInfo->tarFd, buffer, size) != size ) {
				/* Output file seems to have a problem */
				error_msg(io_error, fileName, strerror(errno)); 
				return( FALSE);
			}
			readSize+=size;
		}
		if (size == -1) {
			error_msg(io_error, fileName, strerror(errno)); 
			return( FALSE);
		}
		/* Pad the file up to the tar block size */
		for (; (readSize%TAR_BLOCK_SIZE) != 0; readSize++) {
			write(tbInfo->tarFd, "\0", 1);
		}
		close( inputFileFd);
	}

	return( TRUE);
}

static int writeTarFile(const char* tarName, int verboseFlag, char **argv,
		char** excludeList)
{
	int tarFd=-1;
	int errorFlag=FALSE;
	ssize_t size;
	struct TarBallInfo tbInfo;
	tbInfo.verboseFlag = verboseFlag;
	tbInfo.hlInfoHead = NULL;

	/* Make sure there is at least one file to tar up.  */
	if (*argv == NULL)
		error_msg_and_die("Cowardly refusing to create an empty archive");

	/* Open the tar file for writing.  */
	if (!strcmp(tarName, "-"))
		tbInfo.tarFd = fileno(stdout);
	else
		tbInfo.tarFd = open (tarName, O_WRONLY | O_CREAT | O_TRUNC, 0644);
	if (tbInfo.tarFd < 0) {
		perror_msg( "Error opening '%s'", tarName);
		freeHardLinkInfo(&tbInfo.hlInfoHead);
		return ( FALSE);
	}
	tbInfo.excludeList=excludeList;
	/* Store the stat info for the tarball's file, so
	 * can avoid including the tarball into itself....  */
	if (fstat(tbInfo.tarFd, &tbInfo.statBuf) < 0)
		error_msg_and_die(io_error, tarName, strerror(errno)); 

	/* Read the directory/files and iterate over them one at a time */
	while (*argv != NULL) {
		if (recursive_action(*argv++, TRUE, FALSE, FALSE,
					writeFileToTarball, writeFileToTarball, 
					(void*) &tbInfo) == FALSE) {
			errorFlag = TRUE;
		}
	}
	/* Write two empty blocks to the end of the archive */
	for (size=0; size<(2*TAR_BLOCK_SIZE); size++) {
		write(tbInfo.tarFd, "\0", 1);
	}

	/* To be pedantically correct, we would check if the tarball
	 * is smaller than 20 tar blocks, and pad it if it was smaller,
	 * but that isn't necessary for GNU tar interoperability, and
	 * so is considered a waste of space */

	/* Hang up the tools, close up shop, head home */
	close(tarFd);
	if (errorFlag == TRUE) {
		error_msg("Error exit delayed from previous errors");
		freeHardLinkInfo(&tbInfo.hlInfoHead);
		return(FALSE);
	}
	freeHardLinkInfo(&tbInfo.hlInfoHead);
	return( TRUE);
}


#endif