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