From: Timo Sirainen <tss@iki.fi>
Date: Mon, 9 Sep 2013 21:27:12 +0000 (+0300)
Subject: lib-fs: Added support for giving a hash of the written data to be verified by storage.
X-Git-Tag: 2.2.6~103
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=67a163f3a07593446fab1cbbb8f92a89d4c6cb57;p=thirdparty%2Fdovecot%2Fcore.git

lib-fs: Added support for giving a hash of the written data to be verified by storage.
---

diff --git a/src/lib-fs/fs-api-private.h b/src/lib-fs/fs-api-private.h
index f88a2d8c99..d1acff6b94 100644
--- a/src/lib-fs/fs-api-private.h
+++ b/src/lib-fs/fs-api-private.h
@@ -75,6 +75,9 @@ struct fs_file {
 	struct istream *pending_read_input;
 	bool write_pending;
 
+	const struct hash_method *write_digest_method;
+	void *write_digest;
+
 	pool_t metadata_pool;
 	ARRAY_TYPE(fs_metadata) metadata;
 
diff --git a/src/lib-fs/fs-api.c b/src/lib-fs/fs-api.c
index a9fe3aab0c..3554e6d32f 100644
--- a/src/lib-fs/fs-api.c
+++ b/src/lib-fs/fs-api.c
@@ -4,6 +4,7 @@
 #include "array.h"
 #include "module-dir.h"
 #include "str.h"
+#include "hash-method.h"
 #include "istream.h"
 #include "istream-seekable.h"
 #include "ostream.h"
@@ -199,6 +200,7 @@ void fs_file_close(struct fs_file *file)
 		i_stream_unref(&file->copy_input);
 		(void)fs_write_stream_abort(file, &file->copy_output);
 	}
+	i_free_and_null(file->write_digest);
 	if (file->fs->v.file_close != NULL) T_BEGIN {
 		file->fs->v.file_close(file);
 	} T_END;
@@ -251,6 +253,11 @@ const char *fs_file_path(struct fs_file *file)
 		file->fs->v.get_path(file);
 }
 
+struct fs *fs_file_fs(struct fs_file *file)
+{
+	return file->fs;
+}
+
 static void ATTR_FORMAT(2, 0)
 fs_set_verror(struct fs *fs, const char *fmt, va_list args)
 {
@@ -475,6 +482,16 @@ void fs_write_stream_abort(struct fs_file *file, struct ostream **output)
 	} T_END;
 }
 
+void fs_write_set_hash(struct fs_file *file, const struct hash_method *method,
+		       const void *digest)
+{
+	file->write_digest_method = method;
+
+	i_free(file->write_digest);
+	file->write_digest = i_malloc(method->digest_size);
+	memcpy(file->write_digest, digest, method->digest_size);
+}
+
 void fs_file_set_async_callback(struct fs_file *file,
 				fs_file_async_callback_t *callback,
 				void *context)
diff --git a/src/lib-fs/fs-api.h b/src/lib-fs/fs-api.h
index d2d9a1dd61..228bb6f39c 100644
--- a/src/lib-fs/fs-api.h
+++ b/src/lib-fs/fs-api.h
@@ -5,6 +5,7 @@ struct stat;
 struct fs;
 struct fs_file;
 struct fs_lock;
+struct hash_method;
 
 enum fs_properties {
 	FS_PROPERTY_METADATA	= 0x01,
@@ -19,7 +20,9 @@ enum fs_properties {
 	FS_PROPERTY_RELIABLEITER= 0x40,
 	/* Backend uses directories, which aren't automatically deleted
 	   when its children are deleted. */
-	FS_PROPERTY_DIRECTORIES	= 0x80
+	FS_PROPERTY_DIRECTORIES	= 0x80,
+	FS_PROPERTY_WRITE_HASH_MD5	= 0x100,
+	FS_PROPERTY_WRITE_HASH_SHA256	= 0x200
 };
 
 enum fs_open_mode {
@@ -115,6 +118,8 @@ int fs_get_metadata(struct fs_file *file,
    FS_OPEN_MODE_CREATE_UNIQUE_128 and the write has already finished,
    return the path including the generated filename. */
 const char *fs_file_path(struct fs_file *file);
+/* Returns the file's fs. */
+struct fs *fs_file_fs(struct fs_file *file);
 
 /* Return the error message for the last failed operation. */
 const char *fs_last_error(struct fs *fs);
@@ -151,6 +156,12 @@ int fs_write_stream_finish_async(struct fs_file *file);
 /* Abort writing via stream. Anything written to the stream is discarded. */
 void fs_write_stream_abort(struct fs_file *file, struct ostream **output);
 
+/* Set a hash to the following write. The storage can then verify that the
+   input data matches the specified hash, or fail if it doesn't. Typically
+   implemented by Content-MD5 header. */
+void fs_write_set_hash(struct fs_file *file, const struct hash_method *method,
+		       const void *digest);
+
 /* Call the specified callback whenever the file can be read/written to.
    May call the callback immediately. */
 void fs_file_set_async_callback(struct fs_file *file,