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| author | Denys Vlasenko | 2011-05-04 21:14:12 +0200 |
|---|---|---|
| committer | Denys Vlasenko | 2011-05-04 21:14:12 +0200 |
| commit | 9180c6045e8b2465b3e18a22eb08ee8438ae8544 (patch) | |
| tree | 154bd3a352b89e73098e7923941bb76393dcf604 | |
| parent | 882062915d52581fb754e5721addca72aa789ab7 (diff) | |
| download | busybox-9180c6045e8b2465b3e18a22eb08ee8438ae8544.zip busybox-9180c6045e8b2465b3e18a22eb08ee8438ae8544.tar.gz | |
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.c | 36 | ||||
| -rw-r--r-- | include/archive.h | 2 |
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 */ |