archive-zip: write extended timestamp
File modification times in ZIP files are encoded in DOS format: local time with a granularity of two seconds. Add an extra field to all archive entries to also record the mtime in Unix' fashion, as UTC with a granularity of one second. This has the desirable side-effect of convincing Info-ZIP unzip 6.00 to respect general purpose flag 11, which is used to indicate that a file name is encoded in UTF-8. Any extra field would do, actually, but the extended timestamp is a reasonably small one (22 bytes per entry). Archives created by Info-ZIP zip 3.0 contain it, too (but with ctime and atime as well). Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> Signed-off-by: Junio C Hamano <gitster@pobox.com>
René Scharfe committed
Sep 24, 2012 at 17:56 UTC
227bf59806dc408d60f8f80a14d8dfe71b92c6d2
1 file changed
+24
-3
archive-zip.c
+24
-3
@@ -76,6 +76,14 @@ struct zip_dir_trailer {
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unsigned char _end[1];
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};
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+struct zip_extra_mtime {
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+ unsigned char magic[2];
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+ unsigned char extra_size[2];
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+ unsigned char flags[1];
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+ unsigned char mtime[4];
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+ unsigned char _end[1];
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+};
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+
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/*
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* On ARM, padding is added at the end of the struct, so a simple
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* sizeof(struct ...) reports two bytes more than the payload size
@@ -85,6 +93,9 @@ struct zip_dir_trailer {
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#define ZIP_DATA_DESC_SIZE offsetof(struct zip_data_desc, _end)
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#define ZIP_DIR_HEADER_SIZE offsetof(struct zip_dir_header, _end)
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#define ZIP_DIR_TRAILER_SIZE offsetof(struct zip_dir_trailer, _end)
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+#define ZIP_EXTRA_MTIME_SIZE offsetof(struct zip_extra_mtime, _end)
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+#define ZIP_EXTRA_MTIME_PAYLOAD_SIZE \
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+ (ZIP_EXTRA_MTIME_SIZE - offsetof(struct zip_extra_mtime, flags))
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static void copy_le16(unsigned char *dest, unsigned int n)
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{
@@ -186,6 +197,7 @@ static int write_zip_entry(struct archiver_args *args,
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{
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struct zip_local_header header;
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struct zip_dir_header dirent;
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+ struct zip_extra_mtime extra;
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unsigned long attr2;
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unsigned long compressed_size;
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unsigned long crc;
@@ -266,8 +278,13 @@ static int write_zip_entry(struct archiver_args *args,
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}
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}
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+ copy_le16(extra.magic, 0x5455);
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+ copy_le16(extra.extra_size, ZIP_EXTRA_MTIME_PAYLOAD_SIZE);
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+ extra.flags[0] = 1; /* just mtime */
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+ copy_le32(extra.mtime, args->time);
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+
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/* make sure we have enough free space in the dictionary */
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- direntsize = ZIP_DIR_HEADER_SIZE + pathlen;
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+ direntsize = ZIP_DIR_HEADER_SIZE + pathlen + ZIP_EXTRA_MTIME_SIZE;
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while (zip_dir_size < zip_dir_offset + direntsize) {
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zip_dir_size += ZIP_DIRECTORY_MIN_SIZE;
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zip_dir = xrealloc(zip_dir, zip_dir_size);
@@ -283,7 +300,7 @@ static int write_zip_entry(struct archiver_args *args,
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copy_le16(dirent.mdate, zip_date);
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set_zip_dir_data_desc(&dirent, size, compressed_size, crc);
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copy_le16(dirent.filename_length, pathlen);
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- copy_le16(dirent.extra_length, 0);
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+ copy_le16(dirent.extra_length, ZIP_EXTRA_MTIME_SIZE);
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copy_le16(dirent.comment_length, 0);
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copy_le16(dirent.disk, 0);
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copy_le16(dirent.attr1, 0);
@@ -301,11 +318,13 @@ static int write_zip_entry(struct archiver_args *args,
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else
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set_zip_header_data_desc(&header, size, compressed_size, crc);
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copy_le16(header.filename_length, pathlen);
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- copy_le16(header.extra_length, 0);
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+ copy_le16(header.extra_length, ZIP_EXTRA_MTIME_SIZE);
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write_or_die(1, &header, ZIP_LOCAL_HEADER_SIZE);
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zip_offset += ZIP_LOCAL_HEADER_SIZE;
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write_or_die(1, path, pathlen);
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zip_offset += pathlen;
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+ write_or_die(1, &extra, ZIP_EXTRA_MTIME_SIZE);
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+ zip_offset += ZIP_EXTRA_MTIME_SIZE;
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if (stream && method == 0) {
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unsigned char buf[STREAM_BUFFER_SIZE];
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ssize_t readlen;
@@ -402,6 +421,8 @@ static int write_zip_entry(struct archiver_args *args,
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zip_dir_offset += ZIP_DIR_HEADER_SIZE;
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memcpy(zip_dir + zip_dir_offset, path, pathlen);
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zip_dir_offset += pathlen;
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+ memcpy(zip_dir + zip_dir_offset, &extra, ZIP_EXTRA_MTIME_SIZE);
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+ zip_dir_offset += ZIP_EXTRA_MTIME_SIZE;
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zip_dir_entries++;
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return 0;