1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /*
18  * All code runs under the same UID but sensitive code paths are
19  * run in a separate process with tighter pledge(2) promises.
20  * Data is communicated between processes via imsg_read(3)/imsg_compose(3).
21  * This behaviour is transparent to users of the library.
22  *
23  * File descriptor passing is used in cases where sizes exceed MAX_IMSGSIZE.
24  *
25  * We currently do not exec(2) after a fork(2).
26  * To achieve fork+exec, relevant parts of our library functionality could
27  * be made accessible via separate executables in a libexec directory.
28  */
29 
30 enum got_imsg_type {
31 	/* An error occured while processing a request. */
32 	GOT_IMSG_ERROR,
33 
34 	/*
35 	 * Messages concerned with read access to objects in a repository.
36 	 * Object and pack files are opened by the main process, where
37 	 * data may be read as a byte string but without any interpretation.
38 	 * Decompression and parsing of object and pack files occurs in a
39 	 * separate process which runs under pledge("stdio").
40 	 * This sandboxes our own repository parsing code, as well as zlib.
41 	 */
42 	GOT_IMSG_READ_LOOSE_OBJECT_HEADER_REQUEST,
43 	GOT_IMSG_READ_LOOSE_OBJECT_HEADER_REPLY,
44 	GOT_IMSG_DELTA,
45 	GOT_IMSG_READ_LOOSE_BLOB_OBJECT_REQUEST,
46 	GOT_IMSG_READ_LOOSE_BLOB_OBJECT_REPLY,
47 	GOT_IMSG_READ_LOOSE_TREE_OBJECT_REQUEST,
48 	GOT_IMSG_READ_LOOSE_TREE_OBJECT_REPLY,
49 	GOT_IMSG_READ_LOOSE_COMMIT_OBJECT_REQUEST,
50 	GOT_IMSG_READ_LOOSE_COMMIT_OBJECT_REPLY,
51 	GOT_IMSG_READ_PACKED_BLOB_OBJECT_REQUEST,
52 	GOT_IMSG_READ_PACKED_BLOB_OBJECT_REPLY,
53 	GOT_IMSG_READ_PACKED_TREE_OBJECT_REQUEST,
54 	GOT_IMSG_READ_PACKED_TREE_OBJECT_REPLY,
55 	GOT_IMSG_READ_PACKED_COMMIT_OBJECT_REQUEST,
56 	GOT_IMSG_READ_PACKED_COMMIT_OBJECT_REPLY
57 };
58 
59 /* Structure for GOT_IMSG_ERROR. */
60 struct got_imsg_error {
61 	int code; /* an error code from got_error.h */
62 };
63 
64 /* Structure for GOT_IMSG_READ_LOOSE_OBJECT_HEADER_REQUEST data. */
65 struct got_imsg_read_loose_object_header_request {
66 	/*
67 	 * Empty since the following is implied: If imsg fd == -1 then
68 	 * read raw object data from imsg buffer, else read from fd.
69 	 */
70 };
71 
72 /* Structure for GOT_IMSG_READ_LOOSE_OBJECT_HEADER_REPLY data. */
73 struct got_imsg_read_loose_object_header_reply {
74 	/* These fields are the same as in struct got_object. */
75 	int type;
76 	int flags;
77 	size_t hdrlen;
78 	size_t size;
79 	struct got_object_id id;
80 
81 	int ndeltas; /* this many GOT_IMSG_DELTA messages follow */
82 };
83 
84 /* Structure for GOT_IMSG_DELTA data. */
85 struct got_imsg_delta {
86 	/* These fields are the same as in struct got_delta. */
87 	off_t offset;
88 	size_t tslen;
89 	int type;
90 	size_t size;
91 	off_t data_offset;
92 	size_t delta_len;
93 
94 	/*
95 	 * Followed by raw delta data: If imsg fd == -1 then read
96 	 * delta data from imsg buffer, else read from fd.
97 	 */
98 };
99 
100 /* TODO: Implement the above, and then add more message data types here. */