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authorDenys Vlasenko <vda.linux@googlemail.com>2011-05-04 19:14:12 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2011-05-04 19:14:12 (GMT)
commit9180c6045e8b2465b3e18a22eb08ee8438ae8544 (patch)
tree154bd3a352b89e73098e7923941bb76393dcf604
parent882062915d52581fb754e5721addca72aa789ab7 (diff)
downloadbusybox-9180c6045e8b2465b3e18a22eb08ee8438ae8544.tar.gz
busybox-9180c6045e8b2465b3e18a22eb08ee8438ae8544.tar.bz2
tar: store negative mtime as 0; pack very large files using base-256 encoding
function old new delta writeTarHeader 841 979 +138 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--archival/tar.c36
-rw-r--r--include/archive.h2
2 files changed, 33 insertions, 5 deletions
diff --git a/archival/tar.c b/archival/tar.c
index 01b83d5..ebaa183 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -264,7 +264,8 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
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);
+ /* users report that files with negative st_mtime cause trouble, so: */
+ PUT_OCTAL(header.mtime, statbuf->st_mtime >= 0 ? statbuf->st_mtime : 0);
/* Enter the user and group names */
safe_strncpy(header.uname, get_cached_username(statbuf->st_uid), sizeof(header.uname));
@@ -316,15 +317,42 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
} else if (S_ISFIFO(statbuf->st_mode)) {
header.typeflag = FIFOTYPE;
} else if (S_ISREG(statbuf->st_mode)) {
- if (sizeof(statbuf->st_size) > 4
- && statbuf->st_size > (off_t)0777777777777LL
+ /* header.size field is 12 bytes long */
+ /* Does octal-encoded size fit? */
+ uoff_t filesize = statbuf->st_size;
+ if (sizeof(filesize) <= 4
+ || filesize <= (uoff_t)0777777777777LL
) {
+ PUT_OCTAL(header.size, filesize);
+ }
+ /* Does base256-encoded size fit?
+ * It always does unless off_t is wider than 64 bits.
+ */
+ else if (ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+#if ULLONG_MAX > 0xffffffffffffffffLL /* 2^64-1 */
+ && (filesize <= 0x3fffffffffffffffffffffffLL)
+#endif
+ ) {
+ /* GNU tar uses "base-256 encoding" for very large numbers.
+ * Encoding is binary, with highest bit always set as a marker
+ * and sign in next-highest bit:
+ * 80 00 .. 00 - zero
+ * bf ff .. ff - largest positive number
+ * ff ff .. ff - minus 1
+ * c0 00 .. 00 - smallest negative number
+ */
+ char *p8 = header.size + sizeof(header.size);
+ do {
+ *--p8 = (uint8_t)filesize;
+ filesize >>= 8;
+ } while (p8 != header.size);
+ *p8 |= 0x80;
+ } else {
bb_error_msg_and_die("can't store file '%s' "
"of size %"OFF_FMT"u, aborting",
fileName, statbuf->st_size);
}
header.typeflag = REGTYPE;
- PUT_OCTAL(header.size, statbuf->st_size);
} else {
bb_error_msg("%s: unknown file type", fileName);
return FALSE;
diff --git a/include/archive.h b/include/archive.h
index b139dc5..9e176d3 100644
--- a/include/archive.h
+++ b/include/archive.h
@@ -125,7 +125,7 @@ typedef struct archive_handle_t {
#define TAR_BLOCK_SIZE 512
#define NAME_SIZE 100
#define NAME_SIZE_STR "100"
-typedef struct tar_header_t { /* byte offset */
+typedef struct tar_header_t { /* byte offset */
char name[NAME_SIZE]; /* 0-99 */
char mode[8]; /* 100-107 */
char uid[8]; /* 108-115 */