On 9/1/23 3:26 PM, Gao Xiang wrote:
> `SCHILY.xattr.attr` indicates a POSIX.1-2001 coded version of the
> Linux extended attributes. Let's dump such xattrs to erofs images.
>
> In addition, `LIBARCHIVE.xattr` is also supported, which uses
> URL-Encoding instead of the binary form.
>
> Signed-off-by: Gao Xiang <[email protected]>
Tested-by: Jingbo Xu <[email protected]>
> ---
> changes since v1:
> - fix `SCHILY.xattr.attr` xattr value incorrect sizes reported by Jingbo.
>
> include/erofs/tar.h | 1 +
> lib/tar.c | 171 ++++++++++++++++++++++++++++++++++++++++++--
> mkfs/main.c | 4 +-
> 3 files changed, 171 insertions(+), 5 deletions(-)
>
> diff --git a/include/erofs/tar.h b/include/erofs/tar.h
> index d5648f6..b50db1d 100644
> --- a/include/erofs/tar.h
> +++ b/include/erofs/tar.h
> @@ -13,6 +13,7 @@ extern "C"
>
> struct erofs_pax_header {
> struct stat st;
> + struct list_head xattrs;
> bool use_mtime;
> bool use_size;
> bool use_uid;
> diff --git a/lib/tar.c b/lib/tar.c
> index 328ab98..53196c1 100644
> --- a/lib/tar.c
> +++ b/lib/tar.c
> @@ -235,6 +235,131 @@ static struct erofs_dentry *tarerofs_get_dentry(struct
> erofs_inode *pwd, char *p
> return d;
> }
>
> +struct tarerofs_xattr_item {
> + struct list_head list;
> + char *kv;
> + unsigned int len, namelen;
> +};
> +
> +int tarerofs_insert_xattr(struct list_head *xattrs,
> + char *kv, int namelen, int len, bool skip)
> +{
> + struct tarerofs_xattr_item *item;
> + char *nv;
> +
> + DBG_BUGON(namelen >= len);
> + list_for_each_entry(item, xattrs, list) {
> + if (!strncmp(item->kv, kv, namelen + 1)) {
> + if (skip)
> + return 0;
> + goto found;
> + }
> + }
> +
> + item = malloc(sizeof(*item));
> + if (!item)
> + return -ENOMEM;
> + item->kv = NULL;
> + item->namelen = namelen;
> + namelen = 0;
> + list_add_tail(&item->list, xattrs);
> +found:
> + nv = realloc(item->kv, len);
> + if (!nv)
> + return -ENOMEM;
> + item->kv = nv;
> + item->len = len;
> + memcpy(nv + namelen, kv + namelen, len - namelen);
> + return 0;
> +}
> +
> +int tarerofs_merge_xattrs(struct list_head *dst, struct list_head *src)
> +{
> + struct tarerofs_xattr_item *item;
> +
> + list_for_each_entry(item, src, list) {
> + int ret;
> +
> + ret = tarerofs_insert_xattr(dst, item->kv, item->namelen,
> + item->len, true);
> + if (ret)
> + return ret;
> + }
> + return 0;
> +}
> +
> +void tarerofs_remove_xattrs(struct list_head *xattrs)
> +{
> + struct tarerofs_xattr_item *item, *n;
> +
> + list_for_each_entry_safe(item, n, xattrs, list) {
> + DBG_BUGON(!item->kv);
> + free(item->kv);
> + list_del(&item->list);
> + free(item);
> + }
> +}
> +
> +int tarerofs_apply_xattrs(struct erofs_inode *inode, struct list_head
> *xattrs)
> +{
> + struct tarerofs_xattr_item *item;
> + int ret;
> +
> + list_for_each_entry(item, xattrs, list) {
> + const char *v = item->kv + item->namelen + 1;
> + unsigned int vsz = item->len - item->namelen - 1;
> +
> + if (item->len <= item->namelen - 1) {
> + DBG_BUGON(item->len < item->namelen - 1);
> + continue;
> + }
> + item->kv[item->namelen] = '\0';
> + erofs_dbg("Recording xattr(%s)=\"%s\" (of %u bytes) to file %s",
> + item->kv, v, vsz, inode->i_srcpath);
> + ret = erofs_setxattr(inode, item->kv, v, vsz);
> + if (ret == -ENODATA)
> + erofs_err("Failed to set xattr(%s)=%s to file %s",
> + item->kv, v, inode->i_srcpath);
> + else if (ret)
> + return ret;
> + }
> + return 0;
> +}
> +
> +static const char lookup_table[65] =
> + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
> +
> +static int base64_decode(const char *src, int len, u8 *dst)
> +{
> + int i, bits = 0, ac = 0;
> + const char *p;
> + u8 *cp = dst;
> +
> + if(!(len % 4)) {
> + /* Check for and ignore any end padding */
> + if (src[len - 2] == '=' && src[len - 1] == '=')
> + len -= 2;
> + else if (src[len - 1] == '=')
> + --len;
> + }
> +
> + for (i = 0; i < len; i++) {
> + p = strchr(lookup_table, src[i]);
> + if (p == NULL || src[i] == 0)
> + return -2;
> + ac += (p - lookup_table) << bits;
> + bits += 6;
> + if (bits >= 8) {
> + *cp++ = ac & 0xff;
> + ac >>= 8;
> + bits -= 8;
> + }
> + }
> + if (ac)
> + return -1;
> + return cp - dst;
> +}
> +
> int tarerofs_parse_pax_header(int fd, struct erofs_pax_header *eh, u32 size)
> {
> char *buf, *p;
> @@ -260,6 +385,7 @@ int tarerofs_parse_pax_header(int fd, struct
> erofs_pax_header *eh, u32 size)
> }
> kv = p + n;
> p += len;
> + len -= n;
>
> if (p[-1] != '\n') {
> ret = -EIO;
> @@ -330,6 +456,34 @@ int tarerofs_parse_pax_header(int fd, struct
> erofs_pax_header *eh, u32 size)
> }
> eh->st.st_gid = lln;
> eh->use_gid = true;
> + } else if (!strncmp(kv, "SCHILY.xattr.",
> + sizeof("SCHILY.xattr.") - 1)) {
> + char *key = kv + sizeof("SCHILY.xattr.") - 1;
> +
> + --len; /* p[-1] == '\0' */
> + ret = tarerofs_insert_xattr(&eh->xattrs, key,
> + value - key - 1,
> + len - (key - kv), false);
> + if (ret)
> + goto out;
> + } else if (!strncmp(kv, "LIBARCHIVE.xattr.",
> + sizeof("LIBARCHIVE.xattr.") - 1)) {
> + char *key;
> + key = kv + sizeof("LIBARCHIVE.xattr.") - 1;
> +
> + --len; /* p[-1] == '\0' */
> + ret = base64_decode(value, len - (value - kv),
> + (u8 *)value);
> + if (ret < 0) {
> + ret = -EFSCORRUPTED;
> + goto out;
> + }
> +
> + ret = tarerofs_insert_xattr(&eh->xattrs, key,
> + value - key - 1,
> + value - key + ret, false);
> + if (ret)
> + goto out;
> } else {
> erofs_info("unrecognized pax keyword \"%s\",
> ignoring", kv);
> }
> @@ -416,6 +570,7 @@ int tarerofs_parse_tar(struct erofs_inode *root, struct
> erofs_tarfile *tar)
> eh.path = strdup(eh.path);
> if (eh.link)
> eh.link = strdup(eh.link);
> + init_list_head(&eh.xattrs);
>
> restart:
> rem = tar->offset & 511;
> @@ -723,15 +878,23 @@ new_inode:
> }
> }
> inode->i_nlink++;
> - ret = 0;
> - } else if (!inode->i_nlink)
> + } else if (!inode->i_nlink) {
> ret = erofs_init_empty_dir(inode);
> - else
> - ret = 0;
> + if (ret)
> + goto out;
> + }
> +
> + ret = tarerofs_merge_xattrs(&eh.xattrs, &tar->global.xattrs);
> + if (ret)
> + goto out;
> +
> + ret = tarerofs_apply_xattrs(inode, &eh.xattrs);
> +
> out:
> if (eh.path != path)
> free(eh.path);
> free(eh.link);
> + tarerofs_remove_xattrs(&eh.xattrs);
> return ret;
>
> invalid_tar:
> diff --git a/mkfs/main.c b/mkfs/main.c
> index 16da9c0..4352e62 100644
> --- a/mkfs/main.c
> +++ b/mkfs/main.c
> @@ -132,7 +132,9 @@ static void usage(void)
> }
>
> static unsigned int pclustersize_packed, pclustersize_max;
> -static struct erofs_tarfile erofstar;
> +static struct erofs_tarfile erofstar = {
> + .global.xattrs = LIST_HEAD_INIT(erofstar.global.xattrs)
> +};
> static bool tar_mode;
>
> static int parse_extended_opts(const char *opts)
--
Thanks,
Jingbo
