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 <sys/queue.h>
19 
20 #include <sha1.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <util.h>
25 
26 #include "got_error.h"
27 #include "got_object.h"
28 #include "got_repository.h"
29 #include "got_refs.h"
30 #include "got_sha1.h"
31 
32 #include "path.h"
33 
34 
35 static const struct got_error *
36 parse_symref(struct got_reference **ref, const char *name, const char *line)
37 {
38 	struct got_symref *symref;
39 	char *symref_name;
40 	char *symref_ref;
41 
42 	if (line[0] == '\0')
43 		return got_error(GOT_ERR_NOT_REF);
44 
45 	symref_name = strdup(name);
46 	if (symref_name == NULL)
47 		return got_error(GOT_ERR_NO_MEM);
48 	symref_ref = strdup(line);
49 	if (symref_ref == NULL) {
50 		free(symref_name);
51 		return got_error(GOT_ERR_NO_MEM);
52 	}
53 
54 	*ref = calloc(1, sizeof(**ref));
55 	(*ref)->flags |= GOT_REF_IS_SYMBOLIC;
56 	symref = &((*ref)->ref.symref);
57 	symref->name = symref_name;
58 	symref->ref = symref_ref;
59 	return NULL;
60 }
61 
62 static const struct got_error *
63 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
64 {
65 	uint8_t digest[SHA1_DIGEST_LENGTH];
66 	char *ref_name;
67 
68 	if (strncmp(line, "ref: ", 5) == 0) {
69 		line += 5;
70 		return parse_symref(ref, name, line);
71 	}
72 
73 	ref_name = strdup(name);
74 	if (ref_name == NULL)
75 		return got_error(GOT_ERR_NO_MEM);
76 
77 	if (!got_parse_sha1_digest(digest, line))
78 		return got_error(GOT_ERR_NOT_REF);
79 
80 	*ref = calloc(1, sizeof(**ref));
81 	(*ref)->ref.ref.name = ref_name;
82 	memcpy(&(*ref)->ref.ref.sha1, digest, SHA1_DIGEST_LENGTH);
83 	return NULL;
84 }
85 
86 static const struct got_error *
87 parse_ref_file(struct got_reference **ref, const char *name,
88     const char *abspath)
89 {
90 	const struct got_error *err = NULL;
91 	FILE *f = fopen(abspath, "rb");
92 	char *line;
93 	size_t len;
94 	const char delim[3] = {'\0', '\0', '\0'};
95 
96 	if (f == NULL)
97 		return got_error(GOT_ERR_NOT_REF);
98 
99 	line = fparseln(f, &len, NULL, delim, 0);
100 	if (line == NULL) {
101 		err = got_error(GOT_ERR_NOT_REF);
102 		goto done;
103 	}
104 
105 	err = parse_ref_line(ref, name, line);
106 done:
107 	free(line);
108 	fclose(f);
109 	return err;
110 }
111 
112 static char *
113 get_refs_dir_path(struct got_repository *repo, const char *refname)
114 {
115 	if (strcmp(refname, GOT_REF_HEAD) == 0 ||
116 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
117 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
118 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0 ||
119 	    strncmp(refname, "refs/", 5) == 0)
120 		return got_repo_get_path_git_dir(repo);
121 
122 	return got_repo_get_path_refs(repo);
123 }
124 
125 const struct got_error *
126 got_ref_open(struct got_reference **ref, struct got_repository *repo,
127    const char *refname)
128 {
129 	const struct got_error *err = NULL;
130 	char *path_ref = NULL;
131 	char *normpath = NULL;
132 	const char *parent_dir;
133 	char *path_refs = get_refs_dir_path(repo, refname);
134 
135 	if (path_refs == NULL) {
136 		err = got_error(GOT_ERR_NO_MEM);
137 		goto done;
138 	}
139 	
140 	/* XXX For now, this assumes that refs exist in the filesystem. */
141 
142 	if (asprintf(&path_ref, "%s/%s", path_refs, refname) == -1) {
143 		err = got_error(GOT_ERR_NO_MEM);
144 		goto done;
145 	}
146 
147 	normpath = got_path_normalize(path_ref);
148 	if (normpath == NULL) {
149 		err = got_error(GOT_ERR_NOT_REF);
150 		goto done;
151 	}
152 
153 	err = parse_ref_file(ref, refname, normpath);
154 done:
155 	free(normpath);
156 	free(path_ref);
157 	free(path_refs);
158 	return err;
159 }
160 
161 void
162 got_ref_close(struct got_reference *ref)
163 {
164 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
165 		free(ref->ref.symref.name);
166 	else
167 		free(ref->ref.ref.name);
168 	free(ref);
169 }
170 
171 struct got_reference *
172 got_ref_dup(struct got_reference *ref)
173 {
174 	struct got_reference *ret = calloc(1, sizeof(*ret));
175 	char *name = NULL;
176 	char *symref = NULL;
177 
178 	if (ret == NULL)
179 		return NULL;
180 
181 	ret->flags = ref->flags;
182 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
183 		ret->ref.symref.name = strdup(ref->ref.symref.name);
184 		if (ret->ref.symref.name == NULL) {
185 			free(ret);
186 			return NULL;
187 		}
188 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
189 		if (ret->ref.symref.ref == NULL) {
190 			free(ret->ref.symref.name);
191 			free(ret);
192 			return NULL;
193 		}
194 	} else {
195 		ref->ref.ref.name = strdup(ref->ref.ref.name);
196 		if (ref->ref.ref.name == NULL) {
197 			free(ret);
198 			return NULL;
199 		}
200 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
201 		    SHA1_DIGEST_LENGTH);
202 	}
203 
204 	return ret;
205 }
206 
207 static const struct got_error *
208 resolve_symbolic_ref(struct got_reference **resolved,
209     struct got_repository *repo, struct got_reference *ref)
210 {
211 	struct got_reference *nextref;
212 	const struct got_error *err;
213 
214 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref);
215 	if (err)
216 		return err;
217 
218 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
219 		err = resolve_symbolic_ref(resolved, repo, nextref);
220 	else
221 		*resolved = got_ref_dup(nextref);
222 
223 	got_ref_close(nextref);
224 	return err;
225 }
226 
227 const struct got_error *
228 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
229     struct got_reference *ref)
230 {
231 	const struct got_error *err;
232 
233 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
234 		struct got_reference *resolved = NULL;
235 		err = resolve_symbolic_ref(&resolved, repo, ref);
236 		if (err == NULL)
237 			err = got_ref_resolve(id, repo, resolved);
238 		free(resolved);
239 		return err;
240 	}
241 
242 	*id = calloc(1, sizeof(**id));
243 	if (*id == NULL)
244 		return got_error(GOT_ERR_NO_MEM);
245 	memcpy((*id)->sha1, ref->ref.ref.sha1, SHA1_DIGEST_LENGTH);
246 	return NULL;
247 }