erofs-utils: lib: support GNUTYPE_LONGNAME for tarerofs

The 'L' entry is present in a header for a series of 1 or more 512-byte
tar blocks that hold just the filename for a file or directory with a
name over 100 chars.

Following that series is another header block, in the traditional form:
   A header with type '0' (regular file) or '5' (directory), followed by
   the appropriate number of data blocks with the entry data.

In the header for this series, the name will be truncated to the 1st 100
characters of the actual name.

Tested-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230717073531.43203-1-hsiangkao@linux.alibaba.com

diff --git a/lib/tar.c b/lib/tar.c
index 8edfe758311385e91212a70fb62ac457b5a73d3c..b62e562bd96c2c119725ba13b2704987d4282ca7 100644 (file)
--- a/lib/tar.c
+++ b/lib/tar.c
@@ -570,6 +570,14 @@ restart:
                if (ret)
                        goto out;
                goto restart;
+       } else if (th.typeflag == 'L') {
+               free(eh.path);
+               eh.path = malloc(st.st_size + 1);
+               if (st.st_size != erofs_read_from_fd(tar->fd, eh.path,
+                                                    st.st_size))
+                       goto invalid_tar;
+               eh.path[st.st_size] = '\0';
+               goto restart;
        } else if (th.typeflag == 'K') {
                free(eh.link);
                eh.link = malloc(st.st_size + 1);