libsqfs: Add a SquashFS implementation of the dir_iterator_t

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

4 files changed, 292 insertions, 3 deletions

diff --git a/include/sqfs/io.h b/include/sqfs/io.h
index 91343d6..ce20da2 100644
--- a/include/sqfs/io.h
+++ b/include/sqfs/io.h
@@ -673,6 +673,30 @@ SQFS_API int sqfs_dir_iterator_create_recursive(sqfs_dir_iterator_t **out,
 SQFS_API int sqfs_hard_link_filter_create(sqfs_dir_iterator_t **out,
 					  sqfs_dir_iterator_t *base);
 
+/**
+ * @brief Create a directory iterator
+ *
+ * @memberof sqfs_dir_iterator_t
+ *
+ * @param rd A pointer to a directory reader
+ * @param id A pointer to an ID table
+ * @param data An optional pointer to a data reader. If this is NULL, the
+ *             iterator cannot open files.
+ * @param xattr An optional pointer to an xattr reader. If this is NULL, the
+ *              iterator will pretend that entries do not have extended
+ *              attibutes.
+ * @param inode A pointer to a directory inode to open.
+ * @param out Returns a pointer to a iterator implementation on success.
+ *
+ * @return Zero on success, an @ref SQFS_ERROR code on failure.
+ */
+SQFS_API int sqfs_dir_iterator_create(sqfs_dir_reader_t *rd,
+				      sqfs_id_table_t *id,
+				      sqfs_data_reader_t *data,
+				      sqfs_xattr_reader_t *xattr,
+				      const sqfs_inode_generic_t *inode,
+				      sqfs_dir_iterator_t **out);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/sqfs/Makemodule.am b/lib/sqfs/Makemodule.am
index 14fa215..b40473e 100644
--- a/lib/sqfs/Makemodule.am
+++ b/lib/sqfs/Makemodule.am
@@ -19,7 +19,7 @@ libsquashfs_la_SOURCES = $(LIBSQFS_HEARDS) lib/sqfs/src/id_table.c \
 	lib/sqfs/src/dir_writer.c lib/sqfs/src/xattr/xattr_reader.c \
 	lib/sqfs/src/read_table.c lib/sqfs/src/comp/compressor.c \
 	lib/sqfs/src/comp/internal.h lib/sqfs/src/dir_reader.c \
-	lib/sqfs/src/inode.c \
+	lib/sqfs/src/inode.c lib/sqfs/src/dir_iterator.c \
 	lib/sqfs/src/xattr/xattr_writer.c \
 	lib/sqfs/src/xattr/xattr_writer_flush.c \
 	lib/sqfs/src/xattr/xattr_writer_record.c \
diff --git a/lib/sqfs/src/dir_iterator.c b/lib/sqfs/src/dir_iterator.c
new file mode 100644
index 0000000..3e1f63a
--- /dev/null
+++ b/lib/sqfs/src/dir_iterator.c
@@ -0,0 +1,267 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * dir_iterator.c
+ *
+ * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "sqfs/dir_reader.h"
+#include "sqfs/xattr_reader.h"
+#include "sqfs/dir_entry.h"
+#include "sqfs/error.h"
+#include "sqfs/inode.h"
+#include "sqfs/id_table.h"
+#include "sqfs/data_reader.h"
+#include "sqfs/dir.h"
+#include "sqfs/io.h"
+
+#include "util/util.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct {
+	sqfs_dir_iterator_t base;
+
+	sqfs_dir_reader_state_t state;
+
+	sqfs_u32 xattr_idx;
+	sqfs_inode_generic_t *inode;
+	sqfs_dir_node_t *dent;
+
+	sqfs_xattr_reader_t *xattr;
+	sqfs_data_reader_t *data;
+	sqfs_dir_reader_t *rd;
+	sqfs_id_table_t *id;
+} iterator_t;
+
+static int it_next(sqfs_dir_iterator_t *base, sqfs_dir_entry_t **out)
+{
+	iterator_t *it = (iterator_t *)base;
+	sqfs_dir_entry_t *ent = NULL;
+	sqfs_u32 uid, gid;
+	int ret;
+
+	sqfs_free(it->inode);
+	sqfs_free(it->dent);
+	it->inode = NULL;
+	it->dent = NULL;
+
+	ret = sqfs_dir_reader_read(it->rd, &it->state, &it->dent);
+	if (ret != 0)
+		return ret;
+
+	ret = sqfs_dir_reader_get_inode(it->rd, it->state.ent_ref, &it->inode);
+	if (ret != 0)
+		goto fail;
+
+	ret = SQFS_ERROR_ALLOC;
+	ent = alloc_flex(sizeof(*ent), 1, it->dent->size + 2);
+	if (ent == NULL)
+		goto fail;
+
+	ret = SQFS_ERROR_CORRUPTED;
+	if (sqfs_id_table_index_to_id(it->id, it->inode->base.uid_idx, &uid))
+		goto fail;
+
+	if (sqfs_id_table_index_to_id(it->id, it->inode->base.gid_idx, &gid))
+		goto fail;
+
+	memcpy(ent->name, it->dent->name, it->dent->size + 1);
+
+	ent->mode = it->inode->base.mode;
+	ent->mtime = it->inode->base.mod_time;
+	ent->uid = uid;
+	ent->gid = gid;
+	ent->inode = it->state.ent_ref;
+	it->xattr_idx = 0xFFFFFFFF;
+
+	switch (it->inode->base.type) {
+	case SQFS_INODE_BDEV:
+	case SQFS_INODE_CDEV:
+		ent->rdev = it->inode->data.dev.devno;
+		break;
+	case SQFS_INODE_EXT_BDEV:
+	case SQFS_INODE_EXT_CDEV:
+		ent->rdev = it->inode->data.dev_ext.devno;
+		it->xattr_idx = it->inode->data.dev_ext.xattr_idx;
+		break;
+	case SQFS_INODE_FILE:
+		ent->size = it->inode->data.file.file_size;
+		break;
+	case SQFS_INODE_EXT_FILE:
+		ent->size = it->inode->data.file_ext.file_size;
+		it->xattr_idx = it->inode->data.file_ext.xattr_idx;
+		break;
+	case SQFS_INODE_DIR:
+		ent->size = it->inode->data.dir.size;
+		break;
+	case SQFS_INODE_EXT_DIR:
+		ent->size = it->inode->data.dir_ext.size;
+		it->xattr_idx = it->inode->data.dir_ext.xattr_idx;
+		break;
+	case SQFS_INODE_SLINK:
+		ent->size = it->inode->data.slink.target_size;
+		break;
+	case SQFS_INODE_EXT_SLINK:
+		ent->size = it->inode->data.slink_ext.target_size;
+		it->xattr_idx = it->inode->data.slink_ext.xattr_idx;
+		break;
+	case SQFS_INODE_EXT_FIFO:
+	case SQFS_INODE_EXT_SOCKET:
+		it->xattr_idx = it->inode->data.ipc_ext.xattr_idx;
+		break;
+	default:
+		break;
+	}
+
+	*out = ent;
+	return 0;
+fail:
+	sqfs_free(it->inode);
+	sqfs_free(it->dent);
+	sqfs_free(ent);
+	it->inode = NULL;
+	it->dent = NULL;
+	return ret;
+}
+
+static int it_read_link(sqfs_dir_iterator_t *base, char **out)
+{
+	iterator_t *it = (iterator_t *)base;
+	size_t size;
+
+	*out = NULL;
+
+	if (it->inode == NULL)
+		return SQFS_ERROR_NO_ENTRY;
+
+	if (it->inode->base.type == SQFS_INODE_SLINK) {
+		size = it->inode->data.slink.target_size;
+	} else if (it->inode->base.type == SQFS_INODE_EXT_SLINK) {
+		size = it->inode->data.slink.target_size;
+	} else {
+		return SQFS_ERROR_NO_ENTRY;
+	}
+
+	*out = calloc(1, size + 1);
+	if (*out == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	memcpy(*out, it->inode->extra, size);
+	return 0;
+}
+
+static int it_open_subdir(sqfs_dir_iterator_t *base, sqfs_dir_iterator_t **out)
+{
+	iterator_t *it = (iterator_t *)base;
+
+	*out = NULL;
+
+	if (it->inode == NULL)
+		return SQFS_ERROR_NO_ENTRY;
+
+	if (it->inode->base.type != SQFS_INODE_DIR &&
+	    it->inode->base.type != SQFS_INODE_EXT_DIR) {
+		return SQFS_ERROR_NOT_DIR;
+	}
+
+	return sqfs_dir_iterator_create(it->rd, it->id, it->data, it->xattr,
+					it->inode, out);
+}
+
+static void it_ignore_subdir(sqfs_dir_iterator_t *it)
+{
+	(void)it;
+}
+
+static int it_open_file_ro(sqfs_dir_iterator_t *base, sqfs_istream_t **out)
+{
+	iterator_t *it = (iterator_t *)base;
+
+	if (it->inode == NULL)
+		return SQFS_ERROR_NO_ENTRY;
+
+	if (it->inode->base.type != SQFS_INODE_FILE &&
+	    it->inode->base.type != SQFS_INODE_EXT_FILE) {
+		return SQFS_ERROR_NOT_FILE;
+	}
+
+	if (it->data == NULL)
+		return SQFS_ERROR_UNSUPPORTED;
+
+	return sqfs_data_reader_create_stream(it->data, it->inode,
+					      (const char *)it->dent->name,
+					      out);
+}
+
+static int it_read_xattr(sqfs_dir_iterator_t *base, sqfs_xattr_t **out)
+{
+	iterator_t *it = (iterator_t *)base;
+
+	if (it->inode == NULL)
+		return SQFS_ERROR_NO_ENTRY;
+
+	if (it->xattr == NULL || it->xattr_idx == 0xFFFFFFFF)
+		return 0;
+
+	return sqfs_xattr_reader_read_all(it->xattr, it->xattr_idx, out);
+}
+
+static void it_destroy(sqfs_object_t *obj)
+{
+	iterator_t *it = (iterator_t *)obj;
+
+	sqfs_free(it->inode);
+	sqfs_free(it->dent);
+	sqfs_drop(it->id);
+	sqfs_drop(it->rd);
+	sqfs_drop(it->data);
+	sqfs_drop(it->xattr);
+	sqfs_free(it);
+}
+
+int sqfs_dir_iterator_create(sqfs_dir_reader_t *rd,
+			     sqfs_id_table_t *id,
+			     sqfs_data_reader_t *data,
+			     sqfs_xattr_reader_t *xattr,
+			     const sqfs_inode_generic_t *inode,
+			     sqfs_dir_iterator_t **out)
+{
+	sqfs_dir_iterator_t *base;
+	iterator_t *it;
+	int ret;
+
+	it = calloc(1, sizeof(*it));
+	base = (sqfs_dir_iterator_t *)it;
+
+	if (it == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	sqfs_object_init(it, it_destroy, NULL);
+
+	ret = sqfs_dir_reader_open_dir(rd, inode, &it->state, 0);
+	if (ret) {
+		sqfs_free(it);
+		return ret;
+	}
+
+	base->next = it_next;
+	base->read_link = it_read_link;
+	base->open_subdir = it_open_subdir;
+	base->ignore_subdir = it_ignore_subdir;
+	base->open_file_ro = it_open_file_ro;
+	base->read_xattr = it_read_xattr;
+
+	it->id = sqfs_grab(id);
+	it->rd = sqfs_grab(rd);
+
+	if (data != NULL)
+		it->data = sqfs_grab(data);
+
+	if (xattr != NULL)
+		it->xattr = sqfs_grab(xattr);
+
+	*out = base;
+	return 0;
+}
diff --git a/lib/sqfs/src/dir_reader.c b/lib/sqfs/src/dir_reader.c
index fdb5976..042b93a 100644
--- a/lib/sqfs/src/dir_reader.c
+++ b/lib/sqfs/src/dir_reader.c
@@ -7,8 +7,6 @@
 #define SQFS_BUILDING_DLL
 #include "sqfs/meta_reader.h"
 #include "sqfs/dir_reader.h"
-#include "sqfs/compressor.h"
-#include "sqfs/id_table.h"
 #include "sqfs/super.h"
 #include "sqfs/inode.h"
 #include "sqfs/error.h"