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Merge pull request #91 from landonf/master

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Fix symlink detection
This commit is contained in:
Adam Yanalunas
2014-09-08 11:26:01 -07:00
parent 89b32b9328 653caaa9b2
commit c363747a15
1 changed files with 12 additions and 18 deletions
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SSZipArchive/SSZipArchive.m
+12 -18
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@@ -126,28 +126,22 @@
filename[fileInfo.size_filename] = '\0';
//
// NOTE
// I used the ZIP spec from here:
// http://www.pkware.com/documents/casestudies/APPNOTE.TXT
// Determine whether this is a symbolic link:
// - File is stored with 'version made by' value of UNIX (3),
// as per http://www.pkware.com/documents/casestudies/APPNOTE.TXT
// in the upper byte of the version field.
// - BSD4.4 st_mode constants are stored in the high 16 bits of the
// external file attributes (defacto standard, verified against libarchive)
//
// ...to deduce this method of detecting whether the file in the ZIP is a symbolic link.
// If it is, it is listed as a directory but has a data size greater than zero (real
// directories have it equal to 0) and the included, uncompressed data is the symbolic link path.
// The original constants can be found here:
// http://minnie.tuhs.org/cgi-bin/utree.pl?file=4.4BSD/usr/include/sys/stat.h
//
// ZIP files did not originally include support for symbolic links so the specification
// doesn't include anything in them that isn't part of a unix extension that isn't being used
// by the archivers we're testing. Most of this is figured out through trial and error and
// reading ZIP headers in hex editors. This seems to do the trick though.
//
const uLong ZipCompressionMethodStore = 0;
const uLong ZipUNIXVersion = 3;
const uLong BSD_SFMT = 0170000;
const uLong BSD_IFLNK = 0120000;
BOOL fileIsSymbolicLink = NO;
if((fileInfo.compression_method == ZipCompressionMethodStore) && // Is it compressed?
(S_ISDIR(fileInfo.external_fa)) && // Is it marked as a directory
(fileInfo.compressed_size > 0)) // Is there any data?
{
if (((fileInfo.version >> 8) == ZipUNIXVersion) && BSD_IFLNK == (BSD_SFMT & (fileInfo.external_fa >> 16))) {
fileIsSymbolicLink = YES;
}