1 /*
2  * Copyright (c) 2019 Ori Bernstein <ori@openbsd.org>
3  * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/queue.h>
19 #include <sys/types.h>
20 
21 #include <ctype.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 
26 #include "got_error.h"
27 #include "got_path.h"
28 
29 #include "got_lib_gitproto.h"
30 
31 #ifndef nitems
32 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
33 #endif
34 
35 static const struct got_error *
36 tokenize_refline(char **tokens, char *line, int len, int maxtokens)
37 {
38 	const struct got_error *err = NULL;
39 	char *p;
40 	size_t i, n = 0;
41 
42 	for (i = 0; i < maxtokens; i++)
43 		tokens[i] = NULL;
44 
45 	for (i = 0; n < len && i < maxtokens; i++) {
46 		while (isspace(*line)) {
47 			line++;
48 			n++;
49 		}
50 		p = line;
51 		while (*line != '\0' && n < len &&
52 		    (!isspace(*line) || i == maxtokens - 1)) {
53 			line++;
54 			n++;
55 		}
56 		tokens[i] = strndup(p, line - p);
57 		if (tokens[i] == NULL) {
58 			err = got_error_from_errno("strndup");
59 			goto done;
60 		}
61 		/* Skip \0 field-delimiter at end of token. */
62 		while (line[0] == '\0' && n < len) {
63 			line++;
64 			n++;
65 		}
66 	}
67 	if (i <= 2)
68 		err = got_error(GOT_ERR_BAD_PACKET);
69 done:
70 	if (err) {
71 		int j;
72 		for (j = 0; j < i; j++) {
73 			free(tokens[j]);
74 			tokens[j] = NULL;
75 		}
76 	}
77 	return err;
78 }
79 
80 const struct got_error *
81 got_gitproto_parse_refline(char **id_str, char **refname,
82     char **server_capabilities, char *line, int len)
83 {
84 	const struct got_error *err = NULL;
85 	char *tokens[3];
86 
87 	*id_str = NULL;
88 	*refname = NULL;
89 	/* don't reset *server_capabilities */
90 
91 	err = tokenize_refline(tokens, line, len, nitems(tokens));
92 	if (err)
93 		return err;
94 
95 	if (tokens[0])
96 		*id_str = tokens[0];
97 	if (tokens[1])
98 		*refname = tokens[1];
99 	if (tokens[2]) {
100 		if (*server_capabilities == NULL) {
101 			char *p;
102 			*server_capabilities = tokens[2];
103 			p = strrchr(*server_capabilities, '\n');
104 			if (p)
105 				*p = '\0';
106 		} else
107 			free(tokens[2]);
108 	}
109 
110 	return NULL;
111 }
112 
113 static const struct got_error *
114 match_capability(char **my_capabilities, const char *capa,
115     const struct got_capability *mycapa)
116 {
117 	char *equalsign;
118 	char *s;
119 
120 	equalsign = strchr(capa, '=');
121 	if (equalsign) {
122 		if (strncmp(capa, mycapa->key, equalsign - capa) != 0)
123 			return NULL;
124 	} else {
125 		if (strcmp(capa, mycapa->key) != 0)
126 			return NULL;
127 	}
128 
129 	if (asprintf(&s, "%s %s%s%s",
130 	    *my_capabilities != NULL ? *my_capabilities : "",
131 	    mycapa->key,
132 	    mycapa->value != NULL ? "=" : "",
133 	    mycapa->value != NULL ? mycapa->value : "") == -1)
134 		return got_error_from_errno("asprintf");
135 
136 	free(*my_capabilities);
137 	*my_capabilities = s;
138 	return NULL;
139 }
140 
141 static const struct got_error *
142 add_symref(struct got_pathlist_head *symrefs, char *capa)
143 {
144 	const struct got_error *err = NULL;
145 	char *colon, *name = NULL, *target = NULL;
146 
147 	/* Need at least "A:B" */
148 	if (strlen(capa) < 3)
149 		return NULL;
150 
151 	colon = strchr(capa, ':');
152 	if (colon == NULL)
153 		return NULL;
154 
155 	*colon = '\0';
156 	name = strdup(capa);
157 	if (name == NULL)
158 		return got_error_from_errno("strdup");
159 
160 	target = strdup(colon + 1);
161 	if (target == NULL) {
162 		err = got_error_from_errno("strdup");
163 		goto done;
164 	}
165 
166 	/* We can't validate the ref itself here. The main process will. */
167 	err = got_pathlist_append(symrefs, name, target);
168 done:
169 	if (err) {
170 		free(name);
171 		free(target);
172 	}
173 	return err;
174 }
175 
176 const struct got_error *
177 got_gitproto_match_capabilities(char **common_capabilities,
178     struct got_pathlist_head *symrefs, char *server_capabilities,
179     const struct got_capability my_capabilities[], size_t ncapa)
180 {
181 	const struct got_error *err = NULL;
182 	char *capa, *equalsign;
183 	size_t i;
184 
185 	*common_capabilities = NULL;
186 	do {
187 		capa = strsep(&server_capabilities, " ");
188 		if (capa == NULL)
189 			return NULL;
190 
191 		equalsign = strchr(capa, '=');
192 		if (equalsign != NULL && symrefs != NULL &&
193 		    strncmp(capa, "symref", equalsign - capa) == 0) {
194 			err = add_symref(symrefs, equalsign + 1);
195 			if (err)
196 				break;
197 			continue;
198 		}
199 
200 		for (i = 0; i < ncapa; i++) {
201 			err = match_capability(common_capabilities,
202 			    capa, &my_capabilities[i]);
203 			if (err)
204 				break;
205 		}
206 	} while (capa);
207 
208 	if (*common_capabilities == NULL) {
209 		*common_capabilities = strdup("");
210 		if (*common_capabilities == NULL)
211 			err = got_error_from_errno("strdup");
212 	}
213 	return err;
214 }