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