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 #include <zlib.h>
26 
27 #include "got_error.h"
28 #include "got_object.h"
29 #include "got_repository.h"
30 #include "got_refs.h"
31 #include "got_sha1.h"
32 
33 #include "path.h"
34 
35 
36 static const struct got_error *
37 parse_symref(struct got_reference **ref, const char *name, const char *line)
38 {
39 	struct got_symref *symref;
40 	char *symref_name;
41 	char *symref_ref;
42 
43 	if (line[0] == '\0')
44 		return got_error(GOT_ERR_NOT_REF);
45 
46 	symref_name = strdup(name);
47 	if (symref_name == NULL)
48 		return got_error(GOT_ERR_NO_MEM);
49 	symref_ref = strdup(line);
50 	if (symref_ref == NULL) {
51 		free(symref_name);
52 		return got_error(GOT_ERR_NO_MEM);
53 	}
54 
55 	*ref = calloc(1, sizeof(**ref));
56 	if (*ref == NULL)
57 		return got_error(GOT_ERR_NO_MEM);
58 	(*ref)->flags |= GOT_REF_IS_SYMBOLIC;
59 	symref = &((*ref)->ref.symref);
60 	symref->name = symref_name;
61 	symref->ref = symref_ref;
62 	return NULL;
63 }
64 
65 static const struct got_error *
66 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
67 {
68 	uint8_t digest[SHA1_DIGEST_LENGTH];
69 	char *ref_name;
70 
71 	if (strncmp(line, "ref: ", 5) == 0) {
72 		line += 5;
73 		return parse_symref(ref, name, line);
74 	}
75 
76 	ref_name = strdup(name);
77 	if (ref_name == NULL)
78 		return got_error(GOT_ERR_NO_MEM);
79 
80 	if (!got_parse_sha1_digest(digest, line))
81 		return got_error(GOT_ERR_NOT_REF);
82 
83 	*ref = calloc(1, sizeof(**ref));
84 	if (*ref == NULL)
85 		return got_error(GOT_ERR_NO_MEM);
86 	(*ref)->ref.ref.name = ref_name;
87 	memcpy(&(*ref)->ref.ref.sha1, digest, SHA1_DIGEST_LENGTH);
88 	return NULL;
89 }
90 
91 static const struct got_error *
92 parse_ref_file(struct got_reference **ref, const char *name,
93     const char *abspath)
94 {
95 	const struct got_error *err = NULL;
96 	FILE *f = fopen(abspath, "rb");
97 	char *line;
98 	size_t len;
99 	const char delim[3] = {'\0', '\0', '\0'};
100 
101 	if (f == NULL)
102 		return got_error(GOT_ERR_NOT_REF);
103 
104 	line = fparseln(f, &len, NULL, delim, 0);
105 	if (line == NULL) {
106 		err = got_error(GOT_ERR_NOT_REF);
107 		goto done;
108 	}
109 
110 	err = parse_ref_line(ref, name, line);
111 done:
112 	free(line);
113 	fclose(f);
114 	return err;
115 }
116 
117 static char *
118 get_refs_dir_path(struct got_repository *repo, const char *refname)
119 {
120 	if (strcmp(refname, GOT_REF_HEAD) == 0 ||
121 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
122 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
123 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0 ||
124 	    strncmp(refname, "refs/", 5) == 0)
125 		return got_repo_get_path_git_dir(repo);
126 
127 	return got_repo_get_path_refs(repo);
128 }
129 
130 const struct got_error *
131 got_ref_open(struct got_reference **ref, struct got_repository *repo,
132    const char *refname)
133 {
134 	const struct got_error *err = NULL;
135 	char *path_ref = NULL;
136 	char *normpath = NULL;
137 	const char *parent_dir;
138 	char *path_refs = get_refs_dir_path(repo, refname);
139 
140 	if (path_refs == NULL) {
141 		err = got_error(GOT_ERR_NO_MEM);
142 		goto done;
143 	}
144 	
145 	/* XXX For now, this assumes that refs exist in the filesystem. */
146 
147 	if (asprintf(&path_ref, "%s/%s", path_refs, refname) == -1) {
148 		err = got_error(GOT_ERR_NO_MEM);
149 		goto done;
150 	}
151 
152 	normpath = got_path_normalize(path_ref);
153 	if (normpath == NULL) {
154 		err = got_error(GOT_ERR_NOT_REF);
155 		goto done;
156 	}
157 
158 	err = parse_ref_file(ref, refname, normpath);
159 done:
160 	free(normpath);
161 	free(path_ref);
162 	free(path_refs);
163 	return err;
164 }
165 
166 void
167 got_ref_close(struct got_reference *ref)
168 {
169 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
170 		free(ref->ref.symref.name);
171 	else
172 		free(ref->ref.ref.name);
173 	free(ref);
174 }
175 
176 struct got_reference *
177 got_ref_dup(struct got_reference *ref)
178 {
179 	struct got_reference *ret;
180 	char *name = NULL;
181 	char *symref = NULL;
182 
183 	ret = calloc(1, sizeof(*ret));
184 	if (ret == NULL)
185 		return NULL;
186 
187 	ret->flags = ref->flags;
188 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
189 		ret->ref.symref.name = strdup(ref->ref.symref.name);
190 		if (ret->ref.symref.name == NULL) {
191 			free(ret);
192 			return NULL;
193 		}
194 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
195 		if (ret->ref.symref.ref == NULL) {
196 			free(ret->ref.symref.name);
197 			free(ret);
198 			return NULL;
199 		}
200 	} else {
201 		ref->ref.ref.name = strdup(ref->ref.ref.name);
202 		if (ref->ref.ref.name == NULL) {
203 			free(ret);
204 			return NULL;
205 		}
206 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
207 		    SHA1_DIGEST_LENGTH);
208 	}
209 
210 	return ret;
211 }
212 
213 static const struct got_error *
214 resolve_symbolic_ref(struct got_reference **resolved,
215     struct got_repository *repo, struct got_reference *ref)
216 {
217 	struct got_reference *nextref;
218 	const struct got_error *err;
219 
220 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref);
221 	if (err)
222 		return err;
223 
224 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
225 		err = resolve_symbolic_ref(resolved, repo, nextref);
226 	else
227 		*resolved = got_ref_dup(nextref);
228 
229 	got_ref_close(nextref);
230 	return err;
231 }
232 
233 const struct got_error *
234 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
235     struct got_reference *ref)
236 {
237 	const struct got_error *err;
238 
239 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
240 		struct got_reference *resolved = NULL;
241 		err = resolve_symbolic_ref(&resolved, repo, ref);
242 		if (err == NULL)
243 			err = got_ref_resolve(id, repo, resolved);
244 		free(resolved);
245 		return err;
246 	}
247 
248 	*id = calloc(1, sizeof(**id));
249 	if (*id == NULL)
250 		return got_error(GOT_ERR_NO_MEM);
251 	memcpy((*id)->sha1, ref->ref.ref.sha1, SHA1_DIGEST_LENGTH);
252 	return NULL;
253 }