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/types.h>
19 
20 #include <ctype.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 
25 #include "got_error.h"
26 #include "got_path.h"
27 
28 #include "got_lib_gitproto.h"
29 
30 #ifndef nitems
31 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
32 #endif
33 
34 static const struct got_error *
35 tokenize_refline(char **tokens, char *line, int len, int maxtokens)
36 {
37 	const struct got_error *err = NULL;
38 	char *p;
39 	size_t i, n = 0;
40 
41 	for (i = 0; i < maxtokens; i++)
42 		tokens[i] = NULL;
43 
44 	for (i = 0; n < len && i < maxtokens; i++) {
45 		while (isspace(*line)) {
46 			line++;
47 			n++;
48 		}
49 		p = line;
50 		while (*line != '\0' && n < len &&
51 		    (!isspace(*line) || i == maxtokens - 1)) {
52 			line++;
53 			n++;
54 		}
55 		tokens[i] = strndup(p, line - p);
56 		if (tokens[i] == NULL) {
57 			err = got_error_from_errno("strndup");
58 			goto done;
59 		}
60 		/* Skip \0 field-delimiter at end of token. */
61 		while (line[0] == '\0' && n < len) {
62 			line++;
63 			n++;
64 		}
65 	}
66 	if (i <= 2)
67 		err = got_error(GOT_ERR_BAD_PACKET);
68 done:
69 	if (err) {
70 		int j;
71 		for (j = 0; j < i; j++) {
72 			free(tokens[j]);
73 			tokens[j] = NULL;
74 		}
75 	}
76 	return err;
77 }
78 
79 const struct got_error *
80 got_gitproto_parse_refline(char **id_str, char **refname,
81     char **server_capabilities, char *line, int len)
82 {
83 	const struct got_error *err = NULL;
84 	char *tokens[3];
85 
86 	*id_str = NULL;
87 	*refname = NULL;
88 	/* don't reset *server_capabilities */
89 
90 	err = tokenize_refline(tokens, line, len, nitems(tokens));
91 	if (err)
92 		return err;
93 
94 	if (tokens[0])
95 		*id_str = tokens[0];
96 	if (tokens[1])
97 		*refname = tokens[1];
98 	if (tokens[2]) {
99 		if (*server_capabilities == NULL) {
100 			char *p;
101 			*server_capabilities = tokens[2];
102 			p = strrchr(*server_capabilities, '\n');
103 			if (p)
104 				*p = '\0';
105 		} else
106 			free(tokens[2]);
107 	}
108 
109 	return NULL;
110 }
111 
112 static const struct got_error *
113 match_capability(char **my_capabilities, const char *capa,
114     const struct got_capability *mycapa)
115 {
116 	char *equalsign;
117 	char *s;
118 
119 	equalsign = strchr(capa, '=');
120 	if (equalsign) {
121 		if (strncmp(capa, mycapa->key, equalsign - capa) != 0)
122 			return NULL;
123 	} else {
124 		if (strcmp(capa, mycapa->key) != 0)
125 			return NULL;
126 	}
127 
128 	if (asprintf(&s, "%s %s%s%s",
129 	    *my_capabilities != NULL ? *my_capabilities : "",
130 	    mycapa->key,
131 	    mycapa->value != NULL ? "=" : "",
132 	    mycapa->value != NULL ? mycapa->value : "") == -1)
133 		return got_error_from_errno("asprintf");
134 
135 	free(*my_capabilities);
136 	*my_capabilities = s;
137 	return NULL;
138 }
139 
140 static const struct got_error *
141 add_symref(struct got_pathlist_head *symrefs, char *capa)
142 {
143 	const struct got_error *err = NULL;
144 	char *colon, *name = NULL, *target = NULL;
145 
146 	/* Need at least "A:B" */
147 	if (strlen(capa) < 3)
148 		return NULL;
149 
150 	colon = strchr(capa, ':');
151 	if (colon == NULL)
152 		return NULL;
153 
154 	*colon = '\0';
155 	name = strdup(capa);
156 	if (name == NULL)
157 		return got_error_from_errno("strdup");
158 
159 	target = strdup(colon + 1);
160 	if (target == NULL) {
161 		err = got_error_from_errno("strdup");
162 		goto done;
163 	}
164 
165 	/* We can't validate the ref itself here. The main process will. */
166 	err = got_pathlist_append(symrefs, name, target);
167 done:
168 	if (err) {
169 		free(name);
170 		free(target);
171 	}
172 	return err;
173 }
174 
175 const struct got_error *
176 got_gitproto_match_capabilities(char **common_capabilities,
177     struct got_pathlist_head *symrefs, char *server_capabilities,
178     const struct got_capability my_capabilities[], size_t ncapa)
179 {
180 	const struct got_error *err = NULL;
181 	char *capa, *equalsign;
182 	size_t i;
183 
184 	*common_capabilities = NULL;
185 	do {
186 		capa = strsep(&server_capabilities, " ");
187 		if (capa == NULL)
188 			return NULL;
189 
190 		equalsign = strchr(capa, '=');
191 		if (equalsign != NULL && symrefs != NULL &&
192 		    strncmp(capa, "symref", equalsign - capa) == 0) {
193 			err = add_symref(symrefs, equalsign + 1);
194 			if (err)
195 				break;
196 			continue;
197 		}
198 
199 		for (i = 0; i < ncapa; i++) {
200 			err = match_capability(common_capabilities,
201 			    capa, &my_capabilities[i]);
202 			if (err)
203 				break;
204 		}
205 	} while (capa);
206 
207 	if (*common_capabilities == NULL) {
208 		*common_capabilities = strdup("");
209 		if (*common_capabilities == NULL)
210 			err = got_error_from_errno("strdup");
211 	}
212 	return err;
213 }