+ /* 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 '/' */
+
+ memset(&header, 0, 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);
+ memset(&header, 0, size);
+ xwrite(fd, &header, size);