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