3 files changed, 342 insertions, 248 deletions

diff --git a/lib/tar/src/istream.c b/lib/tar/src/istream.c
deleted file mode 100644
index 80519b1..0000000
--- a/lib/tar/src/istream.c
+++ /dev/null
@@ -1,240 +0,0 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-/*
- * istream.c
- *
- * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
- */
-#include "internal.h"
-
-#include <string.h>
-#include <stdlib.h>
-
-typedef struct {
-	sqfs_u64 offset;
-	sqfs_u64 count;
-} sparse_ent_t;
-
-typedef struct {
-	istream_t base;
-
-	istream_t *parent;
-
-	char *filename;
-
-	sparse_ent_t *sparse;
-	size_t num_sparse;
-
-	sqfs_u64 record_size;
-	sqfs_u64 file_size;
-	sqfs_u64 offset;
-
-	size_t padding;
-	size_t last_chunk;
-	bool last_sparse;
-
-	sqfs_u8 buffer[4096];
-} tar_istream_t;
-
-static bool is_sparse_region(tar_istream_t *tar, sqfs_u64 *count)
-{
-	size_t i;
-
-	*count = tar->file_size - tar->offset;
-	if (tar->num_sparse == 0)
-		return false;
-
-	for (i = 0; i < tar->num_sparse; ++i) {
-		if (tar->offset >= tar->sparse[i].offset) {
-			sqfs_u64 diff = tar->offset - tar->sparse[i].offset;
-
-			if (diff < tar->sparse[i].count) {
-				*count = tar->sparse[i].count - diff;
-				return false;
-			}
-		}
-	}
-
-	for (i = 0; i < tar->num_sparse; ++i) {
-		if (tar->offset < tar->sparse[i].offset) {
-			sqfs_u64 diff = tar->sparse[i].offset - tar->offset;
-
-			if (diff < *count)
-				*count = diff;
-		}
-	}
-
-	return true;
-}
-
-static int precache(istream_t *strm)
-{
-	tar_istream_t *tar = (tar_istream_t *)strm;
-	sqfs_u64 diff, avail;
-
-	tar->offset += tar->last_chunk;
-
-	if (!tar->last_sparse) {
-		tar->parent->buffer_offset += tar->last_chunk;
-		tar->record_size -= tar->last_chunk;
-	}
-
-	if (tar->offset >= tar->file_size) {
-		strm->eof = true;
-		strm->buffer_used = 0;
-		strm->buffer = tar->buffer;
-		if (tar->record_size > 0)
-			goto fail_rec_sz;
-		if (istream_skip(tar->parent, tar->padding))
-			goto fail;
-		tar->padding = 0;
-		return 0;
-	}
-
-	if (is_sparse_region(tar, &diff)) {
-		if (diff > sizeof(tar->buffer))
-			diff = sizeof(tar->buffer);
-
-		strm->buffer = tar->buffer;
-		strm->buffer_used = diff;
-		tar->last_chunk = diff;
-		tar->last_sparse = true;
-
-		memset(tar->buffer, 0, diff);
-	} else {
-		if (diff > tar->record_size)
-			goto fail_rec_sz;
-
-		avail = tar->parent->buffer_used - tar->parent->buffer_offset;
-
-		if ((diff > avail) &&
-		    ((tar->parent->buffer_offset > 0) || avail == 0)) {
-			if (istream_precache(tar->parent))
-				goto fail;
-
-			if (tar->parent->buffer_used == 0 && tar->parent->eof)
-				goto fail_eof;
-
-			avail = tar->parent->buffer_used;
-		}
-
-		if (diff > avail)
-			diff = avail;
-
-		strm->buffer = tar->parent->buffer + tar->parent->buffer_offset;
-		strm->buffer_used = diff;
-		tar->last_chunk = diff;
-		tar->last_sparse = false;
-	}
-
-	return 0;
-fail_rec_sz:
-	fprintf(stderr,
-		"%s: missmatch in tar record size vs file size for `%s`.\n",
-		istream_get_filename(tar->parent), istream_get_filename(strm));
-	goto fail;
-fail_eof:
-	fprintf(stderr, "%s: unexpected end-of-file while reading `%s`\n",
-		istream_get_filename(tar->parent), istream_get_filename(strm));
-	goto fail;
-fail:
-	tar->record_size = 0;
-	tar->padding = 0;
-	return -1;
-}
-
-static const char *get_filename(istream_t *strm)
-{
-	return ((tar_istream_t *)strm)->filename;
-}
-
-static void tar_istream_destroy(sqfs_object_t *obj)
-{
-	tar_istream_t *strm = (tar_istream_t *)obj;
-
-	if (strm->record_size > 0)
-		istream_skip(strm->parent, strm->record_size);
-
-	if (strm->padding > 0)
-		istream_skip(strm->parent, strm->padding);
-
-	sqfs_drop(strm->parent);
-	free(strm->sparse);
-	free(strm->filename);
-	free(strm);
-}
-
-istream_t *tar_record_istream_create(istream_t *parent,
-				     const tar_header_decoded_t *hdr)
-{
-	tar_istream_t *strm;
-	sparse_map_t *it;
-	sqfs_u64 diff;
-	size_t idx;
-
-	strm = calloc(1, sizeof(*strm));
-	if (strm == NULL)
-		goto fail_oom;
-
-	sqfs_object_init(strm, tar_istream_destroy, NULL);
-
-	strm->filename = strdup(hdr->name);
-	if (strm->filename == NULL)
-		goto fail_oom;
-
-	strm->num_sparse = 0;
-	for (it = hdr->sparse; it != NULL; it = it->next)
-		strm->num_sparse += 1;
-
-	if (strm->num_sparse > 0) {
-		strm->sparse = alloc_array(sizeof(strm->sparse[0]),
-					   strm->num_sparse);
-		if (strm->sparse == NULL)
-			goto fail_oom;
-
-		idx = 0;
-		it = hdr->sparse;
-		while (it != NULL && idx < strm->num_sparse) {
-			strm->sparse[idx].offset = it->offset;
-			strm->sparse[idx].count = it->count;
-			++idx;
-			it = it->next;
-		}
-	}
-
-	for (idx = 1; idx < strm->num_sparse; ++idx) {
-		if (strm->sparse[idx].offset <= strm->sparse[idx - 1].offset)
-			goto fail_sparse;
-
-		diff = strm->sparse[idx].offset - strm->sparse[idx - 1].offset;
-
-		if (diff < strm->sparse[idx - 1].count)
-			goto fail_sparse;
-	}
-
-	strm->padding = hdr->record_size % 512;
-	if (strm->padding > 0)
-		strm->padding = 512 - strm->padding;
-
-	strm->record_size = hdr->record_size;
-	strm->file_size = hdr->actual_size;
-	strm->parent = sqfs_grab(parent);
-
-	((istream_t *)strm)->precache = precache;
-	((istream_t *)strm)->get_filename = get_filename;
-	((istream_t *)strm)->buffer = strm->buffer;
-	((istream_t *)strm)->eof = false;
-	return (istream_t *)strm;
-fail_sparse:
-	fprintf(stderr, "%s: sparse map is not ordered or overlapping!\n",
-		hdr->name);
-	goto fail;
-fail_oom:
-	fputs("tar istream create: out-of-memory\n", stderr);
-	goto fail;
-fail:
-	if (strm != NULL) {
-		free(strm->filename);
-		free(strm);
-	}
-	return NULL;
-}
diff --git a/lib/tar/src/iterator.c b/lib/tar/src/iterator.c
new file mode 100644
index 0000000..9a6b9f7
--- /dev/null
+++ b/lib/tar/src/iterator.c
@@ -0,0 +1,339 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * iterator.c
+ *
+ * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "tar/tar.h"
+#include "sqfs/error.h"
+#include "util/util.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+
+typedef struct {
+	dir_iterator_t base;
+	tar_header_decoded_t current;
+	istream_t *stream;
+	int state;
+
+	/* File I/O wrapper related */
+	bool locked;
+
+	sqfs_u64 record_size;
+	sqfs_u64 file_size;
+	sqfs_u64 offset;
+
+	size_t padding;
+	size_t last_chunk;
+	bool last_sparse;
+} tar_iterator_t;
+
+typedef struct {
+	istream_t base;
+
+	tar_iterator_t *parent;
+
+	sqfs_u8 buffer[4096];
+} tar_istream_t;
+
+static bool is_sparse_region(const tar_iterator_t *tar, sqfs_u64 *count)
+{
+	const sparse_map_t *it;
+
+	*count = tar->file_size - tar->offset;
+	if (tar->current.sparse == NULL)
+		return false;
+
+	for (it = tar->current.sparse; it != NULL; it = it->next) {
+		if (tar->offset >= it->offset) {
+			sqfs_u64 diff = tar->offset - it->offset;
+
+			if (diff < it->count) {
+				*count = it->count - diff;
+				return false;
+			}
+		}
+	}
+
+	for (it = tar->current.sparse; it != NULL; it = it->next) {
+		if (tar->offset < it->offset) {
+			sqfs_u64 diff = it->offset - tar->offset;
+
+			if (diff < *count)
+				*count = diff;
+		}
+	}
+
+	return true;
+}
+
+static int data_available(tar_iterator_t *tar, sqfs_u64 want, sqfs_u64 *out)
+{
+	sqfs_u64 avail = tar->stream->buffer_used - tar->stream->buffer_offset;
+
+	if ((want > avail) &&
+	    ((tar->stream->buffer_offset > 0) || avail == 0)) {
+		if (istream_precache(tar->stream)) {
+			tar->state = SQFS_ERROR_IO;
+			return -1;
+		}
+
+		if (tar->stream->buffer_used == 0 && tar->stream->eof) {
+			tar->state = SQFS_ERROR_CORRUPTED;
+			return -1;
+		}
+
+		avail = tar->stream->buffer_used;
+	}
+
+	*out = avail <= want ? avail : want;
+	return 0;
+}
+
+/*****************************************************************************/
+
+static const char *strm_get_filename(istream_t *strm)
+{
+	return ((tar_istream_t *)strm)->parent->current.name;
+}
+
+static int strm_precache(istream_t *strm)
+{
+	tar_istream_t *tar = (tar_istream_t *)strm;
+	sqfs_u64 diff;
+
+	tar->parent->offset += tar->parent->last_chunk;
+
+	if (!tar->parent->last_sparse) {
+		tar->parent->stream->buffer_offset += tar->parent->last_chunk;
+		tar->parent->record_size -= tar->parent->last_chunk;
+	}
+
+	if (tar->parent->offset >= tar->parent->file_size)
+		goto out_eof;
+
+	if (is_sparse_region(tar->parent, &diff)) {
+		if (diff > sizeof(tar->buffer))
+			diff = sizeof(tar->buffer);
+
+		strm->buffer = tar->buffer;
+		strm->buffer_used = diff;
+		tar->parent->last_chunk = diff;
+		tar->parent->last_sparse = true;
+
+		memset(tar->buffer, 0, diff);
+	} else {
+		if (data_available(tar->parent, diff, &diff))
+			goto out_eof;
+
+		strm->buffer = tar->parent->stream->buffer +
+			tar->parent->stream->buffer_offset;
+		strm->buffer_used = diff;
+		tar->parent->last_chunk = diff;
+		tar->parent->last_sparse = false;
+	}
+
+	return 0;
+out_eof:
+	strm->eof = true;
+	strm->buffer_used = 0;
+	strm->buffer = tar->buffer;
+	tar->parent->locked = false;
+	return tar->parent->state < 0 ? -1 : 0;
+}
+
+static void strm_destroy(sqfs_object_t *obj)
+{
+	tar_istream_t *tar = (tar_istream_t *)obj;
+
+	tar->parent->locked = false;
+	sqfs_drop(tar->parent);
+	free(tar);
+}
+
+/*****************************************************************************/
+
+static int it_next(dir_iterator_t *it, dir_entry_t **out)
+{
+	tar_iterator_t *tar = (tar_iterator_t *)it;
+	dir_entry_t *ent;
+	int ret;
+
+	*out = NULL;
+	if (tar->locked)
+		return SQFS_ERROR_SEQUENCE;
+
+	if (tar->state != 0)
+		return tar->state;
+retry:
+	if (tar->record_size > 0) {
+		ret = istream_skip(tar->stream, tar->record_size);
+		if (ret)
+			goto fail;
+	}
+
+	if (tar->padding > 0) {
+		ret = istream_skip(tar->stream, tar->padding);
+		if (ret)
+			goto fail;
+	}
+
+	clear_header(&(tar->current));
+	ret = read_header(tar->stream, &(tar->current));
+	if (ret != 0)
+		goto fail;
+
+	tar->offset = 0;
+	tar->last_chunk = 0;
+	tar->last_sparse = false;
+	tar->record_size = tar->current.record_size;
+	tar->file_size = tar->current.actual_size;
+	tar->padding = tar->current.record_size % 512;
+	if (tar->padding > 0)
+		tar->padding = 512 - tar->padding;
+
+	if (tar->current.unknown_record)
+		goto retry;
+
+	if (canonicalize_name(tar->current.name) != 0) {
+		tar->state = SQFS_ERROR_CORRUPTED;
+		return tar->state;
+	}
+
+	ent = calloc(1, sizeof(*ent) + strlen(tar->current.name) + 1);
+	if (ent == NULL) {
+		tar->state = SQFS_ERROR_ALLOC;
+		return tar->state;
+	}
+
+	ent->mtime = tar->current.mtime;
+	ent->rdev = tar->current.devno;
+	ent->uid = tar->current.uid;
+	ent->gid = tar->current.gid;
+	ent->mode = tar->current.mode;
+	strcpy(ent->name, tar->current.name);
+
+	if (tar->current.is_hard_link) {
+		ent->mode = (S_IFLNK | 0777);
+		ent->flags |= DIR_ENTRY_FLAG_HARD_LINK;
+	}
+
+	if (S_ISREG(ent->mode))
+		ent->size = tar->current.actual_size;
+
+	*out = ent;
+	return 0;
+fail:
+	tar->state = ret < 0 ? SQFS_ERROR_IO : 1;
+	return tar->state;
+}
+
+static int it_read_link(dir_iterator_t *it, char **out)
+{
+	tar_iterator_t *tar = (tar_iterator_t *)it;
+
+	*out = NULL;
+	if (tar->locked)
+		return SQFS_ERROR_SEQUENCE;
+
+	if (tar->state != 0 || tar->current.link_target == NULL)
+		return tar->state < 0 ? tar->state : SQFS_ERROR_NO_ENTRY;
+
+	*out = strdup(tar->current.link_target);
+	return (*out == NULL) ? SQFS_ERROR_ALLOC : 0;
+}
+
+static int it_open_subdir(dir_iterator_t *it, dir_iterator_t **out)
+{
+	(void)it;
+	*out = NULL;
+	return SQFS_ERROR_UNSUPPORTED;
+}
+
+static void it_ignore_subdir(dir_iterator_t *it)
+{
+	(void)it;
+	/* TODO: skip list */
+}
+
+static int it_open_file_ro(dir_iterator_t *it, istream_t **out)
+{
+	tar_iterator_t *tar = (tar_iterator_t *)it;
+	tar_istream_t *strm;
+
+	*out = NULL;
+	if (tar->locked)
+		return SQFS_ERROR_SEQUENCE;
+
+	if (tar->state != 0)
+		return tar->state < 0 ? tar->state : SQFS_ERROR_NO_ENTRY;
+
+	if (!S_ISREG(tar->current.mode))
+		return SQFS_ERROR_NOT_FILE;
+
+	strm = calloc(1, sizeof(*strm));
+	if (strm == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	sqfs_object_init(strm, strm_destroy, NULL);
+	strm->parent = sqfs_grab(tar);
+
+	((istream_t *)strm)->precache = strm_precache;
+	((istream_t *)strm)->get_filename = strm_get_filename;
+	((istream_t *)strm)->buffer = strm->buffer;
+
+	tar->locked = true;
+	*out = (istream_t *)strm;
+	return 0;
+}
+
+static int it_read_xattr(dir_iterator_t *it, dir_entry_xattr_t **out)
+{
+	tar_iterator_t *tar = (tar_iterator_t *)it;
+
+	*out = NULL;
+	if (tar->locked)
+		return SQFS_ERROR_SEQUENCE;
+
+	if (tar->state != 0)
+		return tar->state < 0 ? tar->state : SQFS_ERROR_NO_ENTRY;
+
+	if (tar->current.xattr != NULL) {
+		*out = dir_entry_xattr_list_copy(tar->current.xattr);
+		if (*out == NULL)
+			return SQFS_ERROR_ALLOC;
+	}
+
+	return 0;
+}
+
+static void it_destroy(sqfs_object_t *obj)
+{
+	tar_iterator_t *tar = (tar_iterator_t *)obj;
+
+	clear_header(&(tar->current));
+	sqfs_drop(tar->stream);
+	free(tar);
+}
+
+dir_iterator_t *tar_open_stream(istream_t *stream)
+{
+	tar_iterator_t *tar = calloc(1, sizeof(*tar));
+	dir_iterator_t *it = (dir_iterator_t *)tar;
+
+	if (tar == NULL)
+		return NULL;
+
+	sqfs_object_init(it, it_destroy, NULL);
+	tar->stream = sqfs_grab(stream);
+	it->next = it_next;
+	it->read_link = it_read_link;
+	it->open_subdir = it_open_subdir;
+	it->ignore_subdir = it_ignore_subdir;
+	it->open_file_ro = it_open_file_ro;
+	it->read_xattr = it_read_xattr;
+
+	return it;
+}
diff --git a/lib/tar/src/read_header.c b/lib/tar/src/read_header.c
index 8d3145b..751c5dc 100644
--- a/lib/tar/src/read_header.c
+++ b/lib/tar/src/read_header.c
@@ -224,7 +224,9 @@ int read_header(istream_t *fp, tar_header_decoded_t *out)
 		case TAR_TYPE_PAX_GLOBAL:
 			if (read_number(hdr.size, sizeof(hdr.size), &pax_size))
 				goto fail;
-			skip_entry(fp, pax_size);
+			if (pax_size % 512)
+				pax_size += 512 - (pax_size % 512);
+			istream_skip(fp, pax_size);
 			continue;
 		case TAR_TYPE_PAX:
 			clear_header(out);
@@ -291,10 +293,3 @@ fail:
 	clear_header(out);
 	return -1;
 }
-
-int skip_entry(istream_t *fp, sqfs_u64 size)
-{
-	size_t tail = size % 512;
-
-	return istream_skip(fp, tail ? (size + 512 - tail) : size);
-}