1 /*
2  * Copyright (c) 2017 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 #include <sys/types.h>
18 #include <sha1.h>
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <util.h>
23 
24 #include "got_error.h"
25 #include "got_path.h"
26 #include "got_refs.h"
27 
28 static const struct got_error *
29 parse_symref(struct got_reference **ref, const char *name, const char *line)
30 {
31 	struct got_symref *symref;
32 	char *symref_name;
33 	char *symref_ref;
34 
35 	if (line[0] == '\0')
36 		return got_error(GOT_ERR_NOT_REF);
37 
38 	symref_name = strdup(name);
39 	if (symref_name == NULL)
40 		return got_error(GOT_ERR_NO_MEM);
41 	symref_ref = strdup(line);
42 	if (symref_ref == NULL) {
43 		free(symref_name);
44 		return got_error(GOT_ERR_NO_MEM);
45 	}
46 
47 	*ref = calloc(1, sizeof(**ref));
48 	(*ref)->flags |= GOT_REF_IS_SYMBOLIC;
49 	symref = &((*ref)->ref.symref);
50 	symref->name = symref_name;
51 	symref->ref = symref_ref;
52 	return NULL;
53 }
54 
55 static int
56 parse_sha1_digest(uint8_t *digest, const char *line)
57 {
58 	uint8_t b;
59 	int i, n;
60 
61 	for (i = 0; i < SHA1_DIGEST_LENGTH; i++) {
62 		n = sscanf(line, "%hhx", &b);
63 		if (n == 1)
64 			digest[i] = b;
65 		else
66 			return 0;
67 	}
68 
69 	return 1;
70 }
71 
72 static const struct got_error *
73 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
74 {
75 	uint8_t digest[SHA1_DIGEST_LENGTH];
76 	char *ref_name;
77 
78 	if (strncmp(line, "ref: ", 5) == 0) {
79 		line += 5;
80 		return parse_symref(ref, name, line);
81 	}
82 
83 	ref_name = strdup(name);
84 	if (ref_name == NULL)
85 		return got_error(GOT_ERR_NO_MEM);
86 
87 	if (!parse_sha1_digest(digest, line))
88 		return got_error(GOT_ERR_NOT_REF);
89 
90 	*ref = calloc(1, sizeof(**ref));
91 	(*ref)->ref.ref.name = ref_name;
92 	memcpy(&(*ref)->ref.ref.sha1, digest, SHA1_DIGEST_LENGTH);
93 	return NULL;
94 }
95 
96 static const struct got_error *
97 parse_ref_file(struct got_reference **ref, const char *name,
98     const char *abspath)
99 {
100 	const struct got_error *err = NULL;
101 	FILE *f = fopen(abspath, "rb");
102 	char *line;
103 	size_t len;
104 	const char delim[3] = {'\0', '\0', '\0'};
105 
106 	if (f == NULL)
107 		return got_error(GOT_ERR_NOT_REF);
108 
109 	line = fparseln(f, &len, NULL, delim, 0);
110 	if (line == NULL) {
111 		err = got_error(GOT_ERR_NOT_REF);
112 		goto done;
113 	}
114 
115 	err = parse_ref_line(ref, name, line);
116 done:
117 	free(line);
118 	fclose(f);
119 	return err;
120 }
121 
122 const struct got_error *
123 got_ref_open(struct got_reference **ref, const char *path_refs,
124    const char *refname)
125 {
126 	const struct got_error *err = NULL;
127 	char *path_ref = NULL;
128 	char *normpath = NULL;
129 	const char *parent_dir;
130 	
131 	/* XXX For now, this assumes that refs exist in the filesystem. */
132 
133 	if (asprintf(&path_ref, "%s/%s", path_refs, refname) == -1) {
134 		err = got_error(GOT_ERR_NO_MEM);
135 		goto done;
136 	}
137 
138 	normpath = got_path_normalize(path_ref);
139 	if (normpath == NULL) {
140 		err = got_error(GOT_ERR_NOT_REF);
141 		goto done;
142 	}
143 
144 	err = parse_ref_file(ref, refname, normpath ? normpath : path_refs);
145 done:
146 	free(normpath);
147 	free(path_ref);
148 	return err;
149 }
150 
151 void
152 got_ref_close(struct got_reference *ref)
153 {
154 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
155 		free(ref->ref.symref.name);
156 	else
157 		free(ref->ref.ref.name);
158 	free(ref);
159 }