get external attributes for file in zip

libzip (-lzip)

#include <zip.h>

zip_file_get_external_attributes(zip_t *archive, zip_uint64_t index, zip_flags_t flags, zip_uint8_t *opsys, zip_uint32_t *attributes);

The zip_file_get_external_attributes() function returns the operating system and external attributes for the file at position index in the zip archive. The external attributes usually contain the operating system-specific file permissions. If flags is set to ZIP_FL_UNCHANGED, the original unchanged values are returned. If opsys or attributes are NULL, they are not filled in.

The following operating systems are defined by the zip specification:

The defines above follow the PKWARE Inc. Appnote; please note that the InfoZIP Appnote has a slightly different mapping.

Upon successful completion, 0 is returned. In case of an error, -1 is returned and the error code in archive is set to indicate the error.

The following code can be used to expand attributes if the operating system is ZIP_OPSYS_DOS.
#include <sys/stat.h>

#define FA_RDONLY       0x01            // FILE_ATTRIBUTE_READONLY
#define FA_DIREC        0x10            // FILE_ATTRIBUTE_DIRECTORY

static mode_t
_zip_dos_attr2mode(zip_uint32_t attr)
   mode_t m = S_IRUSR | S_IRGRP | S_IROTH;
   if (0 == (attr & FA_RDONLY))
      m |= S_IWUSR | S_IWGRP | S_IWOTH;

   if (attr & FA_DIREC)
      m = (S_IFDIR | (m & ~S_IFMT)) | S_IXUSR | S_IXGRP | S_IXOTH;

   return m;

zip_file_get_external_attributes() fails if:
index is not a valid file index in archive.

libzip(3), zip_file_set_external_attributes(3)

zip_file_get_external_attributes() was added in libzip 0.11.2.

Dieter Baron <> and Thomas Klausner <>