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