7725d0ff5

Denis Vlasenko

2006-11-25

FAILED Duration: 3s

Subject

tar: add support for FEATURE_TAR_GNU_EXTENSIONS so than we can save long names now. We were able to read such tars, but not create. +275 bytes. Without FEATURE_TAR_GNU_EXTENSIONS: -25 bytes.

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

archival/tar.c +98 -25

archival/tar.c+98 -25

@@ -169,6 +169,72 @@ static void putOctal(char *cp, int len, off_t value)
	/* Copy the string to the field */
	memcpy(cp, tempString, len);
	}
+	#define PUT_OCTAL(a, b) putOctal((a), sizeof(a), (b))
+
+	static void chksum_and_xwrite(int fd, struct TarHeader* hp)
+	{
+	const unsigned char *cp;
+	int chksum, size;
+
+	strcpy(hp->magic, "ustar ");
+
+	/* 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(hp->chksum, ' ', sizeof(hp->chksum));
+	cp = (const unsigned char *) hp;
+	chksum = 0;
+	size = sizeof(*hp);
+	do { chksum += *cp++; } while (--size);
+	putOctal(hp->chksum, sizeof(hp->chksum)-1, chksum);
+
+	/* Now write the header out to disk */
+	xwrite(fd, hp, sizeof(*hp));
+	}
+
+	#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+	static void writeLongname(int fd, int type, const char *name, int dir)
+	{
+	static const struct {
+	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 */
+	} prefilled = {
+	"0000000",
+	"0000000",
+	"0000000",
+	"00000000000",
+	"00000000000",
+	};
+	struct TarHeader header;
+	int size;
+
+	dir = !!dir; /* normalize: 0/1 */
+	size = strlen(name) + 1 + dir; /* GNU tar uses strlen+1 */
+	/* + dir: account for possible '/' */
+
+	bzero(&header, sizeof(header));
+	strcpy(header.name, "././@LongLink");
+	memcpy(header.mode, prefilled.mode, sizeof(prefilled));
+	PUT_OCTAL(header.size, size);
+	header.typeflag = type;
+	chksum_and_xwrite(fd, &header);
+
+	/* Write filename[/] and pad the block. */
+	/* dir=0: writes 'name<NUL>', pads */
+	/* dir=1: writes 'name', writes '/<NUL>', pads */
+	dir *= 2;
+	xwrite(fd, name, size - dir);
+	xwrite(fd, "/", dir);
+	size = (-size) & (TAR_BLOCK_SIZE-1);
+	bzero(&header, size);
+	xwrite(fd, &header, size);
+	}
+	#endif

	/* Write out a tar header for the specified file/directory/whatever */
	void BUG_tar_header_size(void);
@@ -176,25 +242,20 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
	const char header_name, const char fileName, struct stat *statbuf)
	{
	struct TarHeader header;
-	const unsigned char *cp;
-	int chksum;
-	int size;

	if (sizeof(header) != 512)
	BUG_tar_header_size();

	bzero(&header, sizeof(struct TarHeader));

-	safe_strncpy(header.name, header_name, sizeof(header.name));
+	strncpy(header.name, header_name, sizeof(header.name));

-	#define PUT_OCTAL(a, b) putOctal((a), sizeof(a), (b))
	/* POSIX says to mask mode with 07777. */
	PUT_OCTAL(header.mode, statbuf->st_mode & 07777);
	PUT_OCTAL(header.uid, statbuf->st_uid);
	PUT_OCTAL(header.gid, statbuf->st_gid);
	memset(header.size, '0', sizeof(header.size)-1); /* Regular file size is handled later */
	PUT_OCTAL(header.mtime, statbuf->st_mtime);
-	strcpy(header.magic, "ustar ");

	/* Enter the user and group names */
	safe_strncpy(header.uname, get_cached_username(statbuf->st_uid), sizeof(header.uname));
@@ -205,24 +266,36 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
	header.typeflag = LNKTYPE;
	strncpy(header.linkname, tbInfo->hlInfo->name,
	sizeof(header.linkname));
+	#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+	/* Write out long linkname if needed */
+	if (header.linkname[sizeof(header.linkname)-1])
+	writeLongname(tbInfo->tarFd, GNULONGLINK,
+	tbInfo->hlInfo->name, 0);
+	#endif
	} else if (S_ISLNK(statbuf->st_mode)) {
	char *lpath = xreadlink(fileName);
	if (!lpath) /* Already printed err msg inside xreadlink() */
	return FALSE;
	header.typeflag = SYMTYPE;
	strncpy(header.linkname, lpath, sizeof(header.linkname));
+	#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+	/* Write out long linkname if needed */
+	if (header.linkname[sizeof(header.linkname)-1])
+	writeLongname(tbInfo->tarFd, GNULONGLINK, lpath, 0);
+	#else
	/* If it is larger than 100 bytes, bail out */
-	if (header.linkname[sizeof(header.linkname)-1] /* at least 100? */
-	&& lpath[sizeof(header.linkname)] /* and 101th is also not zero */
-	) {
+	if (header.linkname[sizeof(header.linkname)-1]) {
	free(lpath);
	bb_error_msg("names longer than "NAME_SIZE_STR" chars not supported");
	return FALSE;
	}
+	#endif
	free(lpath);
	} else if (S_ISDIR(statbuf->st_mode)) {
	header.typeflag = DIRTYPE;
-	strncat(header.name, "/", sizeof(header.name));
+	/* Append '/' only if there is a space for it */
+	if (!header.name[sizeof(header.name)-1])
+	header.name[strlen(header.name)] = '/';
	} else if (S_ISCHR(statbuf->st_mode)) {
	header.typeflag = CHRTYPE;
	PUT_OCTAL(header.devmajor, major(statbuf->st_rdev));
@@ -247,22 +320,17 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
	bb_error_msg("%s: unknown file type", fileName);
	return FALSE;
	}
-	#undef PUT_OCTAL

-	/* 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;
-	chksum = 0;
-	size = sizeof(struct TarHeader);
-	do { chksum += *cp++; } while (--size);
-	putOctal(header.chksum, sizeof(header.chksum)-1, chksum);
+	#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+	/* Write out long name if needed */
+	/* (we, like GNU tar, output long linkname before long name) */
+	if (header.name[sizeof(header.name)-1])
+	writeLongname(tbInfo->tarFd, GNULONGNAME,
+	header_name, S_ISDIR(statbuf->st_mode));
+	#endif

	/* Now write the header out to disk */
-	xwrite(tbInfo->tarFd, &header, sizeof(struct TarHeader));
+	chksum_and_xwrite(tbInfo->tarFd, &header);

	/* Now do the verbose thing (or not) */
	if (tbInfo->verboseFlag) {
@@ -272,7 +340,9 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
	vbFd = stderr;
	/* GNU "tar cvvf" prints "extended" listing a-la "ls -l" */
	/* We don't have such excesses here: for us "v" == "vv" */
-	fprintf(vbFd, "%s\n", header.name);
+	/* '/' is probably a GNUism */
+	fprintf(vbFd, "%s%s\n", header_name,
+	S_ISDIR(statbuf->st_mode) ? "/" : "");
	}

	return TRUE;
@@ -352,10 +422,12 @@ static int writeFileToTarball(const char fileName, struct stat statbuf,
	header_name++;
	}

+	#if !ENABLE_FEATURE_TAR_GNU_EXTENSIONS
	if (strlen(fileName) >= NAME_SIZE) {
	bb_error_msg("names longer than "NAME_SIZE_STR" chars not supported");
	return TRUE;
	}
+	#endif

	if (header_name[0] == '\0')
	return TRUE;
@@ -384,7 +456,8 @@ static int writeFileToTarball(const char fileName, struct stat statbuf,

	/* write the file to the archive */
	readSize = bb_copyfd_size(inputFileFd, tbInfo->tarFd, statbuf->st_size);
-	if (readSize != statbuf->st_size) {
+	/* readSize < 0 means that error was already reported */
+	if (readSize != statbuf->st_size && readSize >= 0) {
	/* Deadly. We record size into header first, */
	/* and then write out file. If file shrinks in between, */
	/* tar will be corrupted. So bail out. */