sizeof(struct ...)
From: Gerrit Pape <hidden>
Date: 2016-08-11 20:14:50
Subsystem:
the rest · Maintainer:
Linus Torvalds
Hi, I don't think we can rely on sizeof(struct ...) to be the exact size of the struct as defined. As the selftests show, archive-zip doesn't work correctly on Debian/arm http://buildd.debian.org/fetch.cgi?&pkg=git-core&ver=1%3A1.4.4-1&arch=arm&stamp=1164122355&file=log It's because sizeof(struct zip_local_header) is 32, zip_dir_header 48, and zip_dir_trailer 24, breaking the zip files. Compiling with -fpack-struct seemed to break other things, so I for now I ended up with this (not so nice) workaround. Regards, Gerrit.
diff --git a/archive-zip.c b/archive-zip.c
index ae5572a..4fcda44 100644
--- a/archive-zip.c
+++ b/archive-zip.c@@ -211,7 +211,7 @@ static int write_zip_entry(const unsigne } /* make sure we have enough free space in the dictionary */ - direntsize = sizeof(struct zip_dir_header) + pathlen; + direntsize = 46 + pathlen; while (zip_dir_size < zip_dir_offset + direntsize) { zip_dir_size += ZIP_DIRECTORY_MIN_SIZE; zip_dir = xrealloc(zip_dir, zip_dir_size);
@@ -234,8 +234,8 @@ static int write_zip_entry(const unsigne copy_le16(dirent.attr1, 0); copy_le32(dirent.attr2, attr2); copy_le32(dirent.offset, zip_offset); - memcpy(zip_dir + zip_dir_offset, &dirent, sizeof(struct zip_dir_header)); - zip_dir_offset += sizeof(struct zip_dir_header); + memcpy(zip_dir + zip_dir_offset, &dirent, 46); + zip_dir_offset += 46; memcpy(zip_dir + zip_dir_offset, path, pathlen); zip_dir_offset += pathlen; zip_dir_entries++;
@@ -251,8 +251,8 @@ static int write_zip_entry(const unsigne copy_le32(header.size, uncompressed_size); copy_le16(header.filename_length, pathlen); copy_le16(header.extra_length, 0); - write_or_die(1, &header, sizeof(struct zip_local_header)); - zip_offset += sizeof(struct zip_local_header); + write_or_die(1, &header, 30); + zip_offset += 30; write_or_die(1, path, pathlen); zip_offset += pathlen; if (compressed_size > 0) {
@@ -282,7 +282,7 @@ static void write_zip_trailer(const unsi copy_le16(trailer.comment_length, sha1 ? 40 : 0); write_or_die(1, zip_dir, zip_dir_offset); - write_or_die(1, &trailer, sizeof(struct zip_dir_trailer)); + write_or_die(1, &trailer, 22); if (sha1) write_or_die(1, sha1_to_hex(sha1), 40);