From 2810874a0284f9ca7e714fadf0e7d121bb52aa1b Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Mon, 22 Mar 2021 18:17:32 +0000
Subject: [PATCH] libpakfire: Implement restoring snapshots

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/_pakfire/pakfire.c    | 29 ++++++++++++++
 src/libpakfire/snapshot.c | 84 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 112 insertions(+), 1 deletion(-)

diff --git a/src/_pakfire/pakfire.c b/src/_pakfire/pakfire.c
index 92fba567b..88ef89f59 100644
--- a/src/_pakfire/pakfire.c
+++ b/src/_pakfire/pakfire.c
@@ -766,6 +766,29 @@ static PyObject* Pakfire_create_snapshot(PakfireObject* self, PyObject* args) {
 	Py_RETURN_NONE;
 }
 
+static PyObject* Pakfire_restore_snapshot(PakfireObject* self, PyObject* args) {
+	const char* path = NULL;
+
+	if (!PyArg_ParseTuple(args, "s", &path))
+		return NULL;
+
+	FILE* f = fopen(path, "r");
+	if (!f) {
+		PyErr_SetFromErrno(PyExc_OSError);
+		return NULL;
+	}
+
+	int r = pakfire_snapshot_restore(self->pakfire, f);
+	fclose(f);
+
+	if (r) {
+		PyErr_SetFromErrno(PyExc_OSError);
+		return NULL;
+	}
+
+	Py_RETURN_NONE;
+}
+
 static struct PyMethodDef Pakfire_methods[] = {
 	{
 		"bind",
@@ -851,6 +874,12 @@ static struct PyMethodDef Pakfire_methods[] = {
 		METH_VARARGS,
 		NULL
 	},
+	{
+		"restore_snapshot",
+		(PyCFunction)Pakfire_restore_snapshot,
+		METH_VARARGS,
+		NULL,
+	},
 	{
 		"version_compare",
 		(PyCFunction)Pakfire_version_compare,
diff --git a/src/libpakfire/snapshot.c b/src/libpakfire/snapshot.c
index 0e626acf0..73309a599 100644
--- a/src/libpakfire/snapshot.c
+++ b/src/libpakfire/snapshot.c
@@ -20,6 +20,7 @@
 
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include <archive.h>
 
@@ -155,6 +156,13 @@ PAKFIRE_EXPORT int pakfire_snapshot_create(Pakfire pakfire, FILE* f) {
 		pakfire_file_unref(file);
 	}
 
+	// Close archive
+	r = archive_write_close(a);
+	if (r) {
+		ERROR(pakfire, "Could not close archive: %s\n", archive_error_string(a));
+		goto ERROR;
+	}
+
 	// Success
 	r = 0;
 
@@ -168,5 +176,79 @@ ERROR:
 }
 
 PAKFIRE_EXPORT int pakfire_snapshot_restore(Pakfire pakfire, FILE* f) {
-	return 0;
+	int r = 1;
+
+	struct archive* a = archive_read_new();
+	if (!a)
+		return 1;
+
+	// All snapshots are tarballs
+	archive_read_support_format_tar(a);
+
+	// And they are compressed using ZSTD
+	archive_read_support_filter_zstd(a);
+
+	struct archive* disk = archive_write_disk_new();
+	if (!disk)
+		goto ERROR;
+
+	// Set flags for extracting contents
+	const int flags =
+		ARCHIVE_EXTRACT_ACL |
+		ARCHIVE_EXTRACT_OWNER |
+		ARCHIVE_EXTRACT_PERM |
+		ARCHIVE_EXTRACT_SPARSE |
+		ARCHIVE_EXTRACT_TIME |
+		ARCHIVE_EXTRACT_UNLINK |
+		ARCHIVE_EXTRACT_XATTR;
+
+	archive_write_disk_set_options(disk, flags);
+
+	// Open the given file for reading
+	r = archive_read_open_FILE(a, f);
+	if (r) {
+		ERROR(pakfire, "Could not open archive: %s\n", archive_error_string(a));
+		goto ERROR;
+	}
+
+	struct archive_entry* e = NULL;
+	while (1) {
+		r = archive_read_next_header(a, &e);
+		if (r == ARCHIVE_EOF)
+			break;
+		else if (r) {
+			ERROR(pakfire, "Could not read header: %s\n", archive_error_string(a));
+			goto ERROR;
+		}
+
+		const char* path = archive_entry_pathname(e);
+
+		DEBUG(pakfire, "Extracting %s...\n", path);
+
+		// Update path
+		char* sourcepath = pakfire_make_path(pakfire, path);
+		if (!sourcepath)
+			goto ERROR;
+
+		archive_entry_set_pathname(e, sourcepath);
+		free(sourcepath);
+
+		// Extract the file
+		r = archive_read_extract2(a, e, disk);
+		if (r) {
+			ERROR(pakfire, "Could not extract %s: %s\n",
+				archive_entry_pathname(e), archive_error_string(a));
+			goto ERROR;
+		}
+	}
+
+	// Success
+	r = 0;
+
+ERROR:
+	if (disk)
+		archive_write_free(disk);
+	archive_read_free(a);
+
+	return r;
 }
-- 
2.47.2