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1 | #include "cache.h" | |
2 | #include "repository.h" | |
3 | #include "config.h" | |
4 | #include "pkt-line.h" | |
5 | #include "version.h" | |
6 | #include "strvec.h" | |
7 | #include "ls-refs.h" | |
8 | #include "serve.h" | |
9 | #include "upload-pack.h" | |
10 | ||
11 | static int always_advertise(struct repository *r, | |
12 | struct strbuf *value) | |
13 | { | |
14 | return 1; | |
15 | } | |
16 | ||
17 | static int agent_advertise(struct repository *r, | |
18 | struct strbuf *value) | |
19 | { | |
20 | if (value) | |
21 | strbuf_addstr(value, git_user_agent_sanitized()); | |
22 | return 1; | |
23 | } | |
24 | ||
25 | static int object_format_advertise(struct repository *r, | |
26 | struct strbuf *value) | |
27 | { | |
28 | if (value) | |
29 | strbuf_addstr(value, r->hash_algo->name); | |
30 | return 1; | |
31 | } | |
32 | ||
33 | struct protocol_capability { | |
34 | /* | |
35 | * The name of the capability. The server uses this name when | |
36 | * advertising this capability, and the client uses this name to | |
37 | * specify this capability. | |
38 | */ | |
39 | const char *name; | |
40 | ||
41 | /* | |
42 | * Function queried to see if a capability should be advertised. | |
43 | * Optionally a value can be specified by adding it to 'value'. | |
44 | * If a value is added to 'value', the server will advertise this | |
45 | * capability as "<name>=<value>" instead of "<name>". | |
46 | */ | |
47 | int (*advertise)(struct repository *r, struct strbuf *value); | |
48 | ||
49 | /* | |
50 | * Function called when a client requests the capability as a command. | |
51 | * The function will be provided the capabilities requested via 'keys' | |
52 | * as well as a struct packet_reader 'request' which the command should | |
53 | * use to read the command specific part of the request. Every command | |
54 | * MUST read until a flush packet is seen before sending a response. | |
55 | * | |
56 | * This field should be NULL for capabilities which are not commands. | |
57 | */ | |
58 | int (*command)(struct repository *r, | |
59 | struct strvec *keys, | |
60 | struct packet_reader *request); | |
61 | }; | |
62 | ||
63 | static struct protocol_capability capabilities[] = { | |
64 | { "agent", agent_advertise, NULL }, | |
65 | { "ls-refs", always_advertise, ls_refs }, | |
66 | { "fetch", upload_pack_advertise, upload_pack_v2 }, | |
67 | { "server-option", always_advertise, NULL }, | |
68 | { "object-format", object_format_advertise, NULL }, | |
69 | }; | |
70 | ||
71 | static void advertise_capabilities(void) | |
72 | { | |
73 | struct strbuf capability = STRBUF_INIT; | |
74 | struct strbuf value = STRBUF_INIT; | |
75 | int i; | |
76 | ||
77 | for (i = 0; i < ARRAY_SIZE(capabilities); i++) { | |
78 | struct protocol_capability *c = &capabilities[i]; | |
79 | ||
80 | if (c->advertise(the_repository, &value)) { | |
81 | strbuf_addstr(&capability, c->name); | |
82 | ||
83 | if (value.len) { | |
84 | strbuf_addch(&capability, '='); | |
85 | strbuf_addbuf(&capability, &value); | |
86 | } | |
87 | ||
88 | strbuf_addch(&capability, '\n'); | |
89 | packet_write(1, capability.buf, capability.len); | |
90 | } | |
91 | ||
92 | strbuf_reset(&capability); | |
93 | strbuf_reset(&value); | |
94 | } | |
95 | ||
96 | packet_flush(1); | |
97 | strbuf_release(&capability); | |
98 | strbuf_release(&value); | |
99 | } | |
100 | ||
101 | static struct protocol_capability *get_capability(const char *key) | |
102 | { | |
103 | int i; | |
104 | ||
105 | if (!key) | |
106 | return NULL; | |
107 | ||
108 | for (i = 0; i < ARRAY_SIZE(capabilities); i++) { | |
109 | struct protocol_capability *c = &capabilities[i]; | |
110 | const char *out; | |
111 | if (skip_prefix(key, c->name, &out) && (!*out || *out == '=')) | |
112 | return c; | |
113 | } | |
114 | ||
115 | return NULL; | |
116 | } | |
117 | ||
118 | static int is_valid_capability(const char *key) | |
119 | { | |
120 | const struct protocol_capability *c = get_capability(key); | |
121 | ||
122 | return c && c->advertise(the_repository, NULL); | |
123 | } | |
124 | ||
125 | static int is_command(const char *key, struct protocol_capability **command) | |
126 | { | |
127 | const char *out; | |
128 | ||
129 | if (skip_prefix(key, "command=", &out)) { | |
130 | struct protocol_capability *cmd = get_capability(out); | |
131 | ||
132 | if (*command) | |
133 | die("command '%s' requested after already requesting command '%s'", | |
134 | out, (*command)->name); | |
135 | if (!cmd || !cmd->advertise(the_repository, NULL) || !cmd->command) | |
136 | die("invalid command '%s'", out); | |
137 | ||
138 | *command = cmd; | |
139 | return 1; | |
140 | } | |
141 | ||
142 | return 0; | |
143 | } | |
144 | ||
145 | int has_capability(const struct strvec *keys, const char *capability, | |
146 | const char **value) | |
147 | { | |
148 | int i; | |
149 | for (i = 0; i < keys->nr; i++) { | |
150 | const char *out; | |
151 | if (skip_prefix(keys->v[i], capability, &out) && | |
152 | (!*out || *out == '=')) { | |
153 | if (value) { | |
154 | if (*out == '=') | |
155 | out++; | |
156 | *value = out; | |
157 | } | |
158 | return 1; | |
159 | } | |
160 | } | |
161 | ||
162 | return 0; | |
163 | } | |
164 | ||
165 | static void check_algorithm(struct repository *r, struct strvec *keys) | |
166 | { | |
167 | int client = GIT_HASH_SHA1, server = hash_algo_by_ptr(r->hash_algo); | |
168 | const char *algo_name; | |
169 | ||
170 | if (has_capability(keys, "object-format", &algo_name)) { | |
171 | client = hash_algo_by_name(algo_name); | |
172 | if (client == GIT_HASH_UNKNOWN) | |
173 | die("unknown object format '%s'", algo_name); | |
174 | } | |
175 | ||
176 | if (client != server) | |
177 | die("mismatched object format: server %s; client %s\n", | |
178 | r->hash_algo->name, hash_algos[client].name); | |
179 | } | |
180 | ||
181 | enum request_state { | |
182 | PROCESS_REQUEST_KEYS, | |
183 | PROCESS_REQUEST_DONE, | |
184 | }; | |
185 | ||
186 | static int process_request(void) | |
187 | { | |
188 | enum request_state state = PROCESS_REQUEST_KEYS; | |
189 | struct packet_reader reader; | |
190 | struct strvec keys = STRVEC_INIT; | |
191 | struct protocol_capability *command = NULL; | |
192 | ||
193 | packet_reader_init(&reader, 0, NULL, 0, | |
194 | PACKET_READ_CHOMP_NEWLINE | | |
195 | PACKET_READ_GENTLE_ON_EOF | | |
196 | PACKET_READ_DIE_ON_ERR_PACKET); | |
197 | ||
198 | /* | |
199 | * Check to see if the client closed their end before sending another | |
200 | * request. If so we can terminate the connection. | |
201 | */ | |
202 | if (packet_reader_peek(&reader) == PACKET_READ_EOF) | |
203 | return 1; | |
204 | reader.options &= ~PACKET_READ_GENTLE_ON_EOF; | |
205 | ||
206 | while (state != PROCESS_REQUEST_DONE) { | |
207 | switch (packet_reader_peek(&reader)) { | |
208 | case PACKET_READ_EOF: | |
209 | BUG("Should have already died when seeing EOF"); | |
210 | case PACKET_READ_NORMAL: | |
211 | /* collect request; a sequence of keys and values */ | |
212 | if (is_command(reader.line, &command) || | |
213 | is_valid_capability(reader.line)) | |
214 | strvec_push(&keys, reader.line); | |
215 | else | |
216 | die("unknown capability '%s'", reader.line); | |
217 | ||
218 | /* Consume the peeked line */ | |
219 | packet_reader_read(&reader); | |
220 | break; | |
221 | case PACKET_READ_FLUSH: | |
222 | /* | |
223 | * If no command and no keys were given then the client | |
224 | * wanted to terminate the connection. | |
225 | */ | |
226 | if (!keys.nr) | |
227 | return 1; | |
228 | ||
229 | /* | |
230 | * The flush packet isn't consume here like it is in | |
231 | * the other parts of this switch statement. This is | |
232 | * so that the command can read the flush packet and | |
233 | * see the end of the request in the same way it would | |
234 | * if command specific arguments were provided after a | |
235 | * delim packet. | |
236 | */ | |
237 | state = PROCESS_REQUEST_DONE; | |
238 | break; | |
239 | case PACKET_READ_DELIM: | |
240 | /* Consume the peeked line */ | |
241 | packet_reader_read(&reader); | |
242 | ||
243 | state = PROCESS_REQUEST_DONE; | |
244 | break; | |
245 | case PACKET_READ_RESPONSE_END: | |
246 | BUG("unexpected stateless separator packet"); | |
247 | } | |
248 | } | |
249 | ||
250 | if (!command) | |
251 | die("no command requested"); | |
252 | ||
253 | check_algorithm(the_repository, &keys); | |
254 | ||
255 | command->command(the_repository, &keys, &reader); | |
256 | ||
257 | strvec_clear(&keys); | |
258 | return 0; | |
259 | } | |
260 | ||
261 | /* Main serve loop for protocol version 2 */ | |
262 | void serve(struct serve_options *options) | |
263 | { | |
264 | if (options->advertise_capabilities || !options->stateless_rpc) { | |
265 | /* serve by default supports v2 */ | |
266 | packet_write_fmt(1, "version 2\n"); | |
267 | ||
268 | advertise_capabilities(); | |
269 | /* | |
270 | * If only the list of capabilities was requested exit | |
271 | * immediately after advertising capabilities | |
272 | */ | |
273 | if (options->advertise_capabilities) | |
274 | return; | |
275 | } | |
276 | ||
277 | /* | |
278 | * If stateless-rpc was requested then exit after | |
279 | * a single request/response exchange | |
280 | */ | |
281 | if (options->stateless_rpc) { | |
282 | process_request(); | |
283 | } else { | |
284 | for (;;) | |
285 | if (process_request()) | |
286 | break; | |
287 | } | |
288 | } |