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 #include "delta.h"
35 #include "zb.h"
36 #include "object.h"
37 #include "refs.h"
38 
39 static const struct got_error *
40 parse_symref(struct got_reference **ref, const char *name, const char *line)
41 {
42 	struct got_symref *symref;
43 	char *symref_name;
44 	char *symref_ref;
45 
46 	if (line[0] == '\0')
47 		return got_error(GOT_ERR_NOT_REF);
48 
49 	symref_name = strdup(name);
50 	if (symref_name == NULL)
51 		return got_error(GOT_ERR_NO_MEM);
52 	symref_ref = strdup(line);
53 	if (symref_ref == NULL) {
54 		free(symref_name);
55 		return got_error(GOT_ERR_NO_MEM);
56 	}
57 
58 	*ref = calloc(1, sizeof(**ref));
59 	if (*ref == NULL)
60 		return got_error(GOT_ERR_NO_MEM);
61 	(*ref)->flags |= GOT_REF_IS_SYMBOLIC;
62 	symref = &((*ref)->ref.symref);
63 	symref->name = symref_name;
64 	symref->ref = symref_ref;
65 	return NULL;
66 }
67 
68 static const struct got_error *
69 parse_ref_line(struct got_reference **ref, const char *name, const char *line)
70 {
71 	uint8_t digest[SHA1_DIGEST_LENGTH];
72 	char *ref_name;
73 
74 	if (strncmp(line, "ref: ", 5) == 0) {
75 		line += 5;
76 		return parse_symref(ref, name, line);
77 	}
78 
79 	ref_name = strdup(name);
80 	if (ref_name == NULL)
81 		return got_error(GOT_ERR_NO_MEM);
82 
83 	if (!got_parse_sha1_digest(digest, line))
84 		return got_error(GOT_ERR_NOT_REF);
85 
86 	*ref = calloc(1, sizeof(**ref));
87 	if (*ref == NULL)
88 		return got_error(GOT_ERR_NO_MEM);
89 	(*ref)->ref.ref.name = ref_name;
90 	memcpy(&(*ref)->ref.ref.sha1, digest, SHA1_DIGEST_LENGTH);
91 	return NULL;
92 }
93 
94 static const struct got_error *
95 parse_ref_file(struct got_reference **ref, const char *name,
96     const char *abspath)
97 {
98 	const struct got_error *err = NULL;
99 	FILE *f = fopen(abspath, "rb");
100 	char *line;
101 	size_t len;
102 	const char delim[3] = {'\0', '\0', '\0'};
103 
104 	if (f == NULL)
105 		return got_error(GOT_ERR_NOT_REF);
106 
107 	line = fparseln(f, &len, NULL, delim, 0);
108 	if (line == NULL) {
109 		err = got_error(GOT_ERR_NOT_REF);
110 		goto done;
111 	}
112 
113 	err = parse_ref_line(ref, name, line);
114 done:
115 	free(line);
116 	fclose(f);
117 	return err;
118 }
119 
120 static char *
121 get_refs_dir_path(struct got_repository *repo, const char *refname)
122 {
123 	if (strcmp(refname, GOT_REF_HEAD) == 0 ||
124 	    strcmp(refname, GOT_REF_ORIG_HEAD) == 0 ||
125 	    strcmp(refname, GOT_REF_MERGE_HEAD) == 0 ||
126 	    strcmp(refname, GOT_REF_FETCH_HEAD) == 0 ||
127 	    strncmp(refname, "refs/", 5) == 0)
128 		return got_repo_get_path_git_dir(repo);
129 
130 	return got_repo_get_path_refs(repo);
131 }
132 
133 const struct got_error *
134 got_ref_open(struct got_reference **ref, struct got_repository *repo,
135    const char *refname)
136 {
137 	const struct got_error *err = NULL;
138 	char *path_ref = NULL;
139 	char *normpath = NULL;
140 	const char *parent_dir;
141 	char *path_refs = get_refs_dir_path(repo, refname);
142 
143 	if (path_refs == NULL) {
144 		err = got_error(GOT_ERR_NO_MEM);
145 		goto done;
146 	}
147 	
148 	/* XXX For now, this assumes that refs exist in the filesystem. */
149 
150 	if (asprintf(&path_ref, "%s/%s", path_refs, refname) == -1) {
151 		err = got_error(GOT_ERR_NO_MEM);
152 		goto done;
153 	}
154 
155 	normpath = got_path_normalize(path_ref);
156 	if (normpath == NULL) {
157 		err = got_error(GOT_ERR_NOT_REF);
158 		goto done;
159 	}
160 
161 	err = parse_ref_file(ref, refname, normpath);
162 done:
163 	free(normpath);
164 	free(path_ref);
165 	free(path_refs);
166 	return err;
167 }
168 
169 void
170 got_ref_close(struct got_reference *ref)
171 {
172 	if (ref->flags & GOT_REF_IS_SYMBOLIC)
173 		free(ref->ref.symref.name);
174 	else
175 		free(ref->ref.ref.name);
176 	free(ref);
177 }
178 
179 struct got_reference *
180 got_ref_dup(struct got_reference *ref)
181 {
182 	struct got_reference *ret;
183 	char *name = NULL;
184 	char *symref = NULL;
185 
186 	ret = calloc(1, sizeof(*ret));
187 	if (ret == NULL)
188 		return NULL;
189 
190 	ret->flags = ref->flags;
191 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
192 		ret->ref.symref.name = strdup(ref->ref.symref.name);
193 		if (ret->ref.symref.name == NULL) {
194 			free(ret);
195 			return NULL;
196 		}
197 		ret->ref.symref.ref = strdup(ref->ref.symref.ref);
198 		if (ret->ref.symref.ref == NULL) {
199 			free(ret->ref.symref.name);
200 			free(ret);
201 			return NULL;
202 		}
203 	} else {
204 		ref->ref.ref.name = strdup(ref->ref.ref.name);
205 		if (ref->ref.ref.name == NULL) {
206 			free(ret);
207 			return NULL;
208 		}
209 		memcpy(ret->ref.ref.sha1, ref->ref.ref.sha1,
210 		    SHA1_DIGEST_LENGTH);
211 	}
212 
213 	return ret;
214 }
215 
216 static const struct got_error *
217 resolve_symbolic_ref(struct got_reference **resolved,
218     struct got_repository *repo, struct got_reference *ref)
219 {
220 	struct got_reference *nextref;
221 	const struct got_error *err;
222 
223 	err = got_ref_open(&nextref, repo, ref->ref.symref.ref);
224 	if (err)
225 		return err;
226 
227 	if (nextref->flags & GOT_REF_IS_SYMBOLIC)
228 		err = resolve_symbolic_ref(resolved, repo, nextref);
229 	else
230 		*resolved = got_ref_dup(nextref);
231 
232 	got_ref_close(nextref);
233 	return err;
234 }
235 
236 const struct got_error *
237 got_ref_resolve(struct got_object_id **id, struct got_repository *repo,
238     struct got_reference *ref)
239 {
240 	const struct got_error *err;
241 
242 	if (ref->flags & GOT_REF_IS_SYMBOLIC) {
243 		struct got_reference *resolved = NULL;
244 		err = resolve_symbolic_ref(&resolved, repo, ref);
245 		if (err == NULL)
246 			err = got_ref_resolve(id, repo, resolved);
247 		free(resolved);
248 		return err;
249 	}
250 
251 	*id = calloc(1, sizeof(**id));
252 	if (*id == NULL)
253 		return got_error(GOT_ERR_NO_MEM);
254 	memcpy((*id)->sha1, ref->ref.ref.sha1, SHA1_DIGEST_LENGTH);
255 	return NULL;
256 }