receive-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include "run-command.h"
   5 #include "commit.h"
   6 #include "object.h"
   7
   8 static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
   9
  10 static const char *unpacker[] = { "unpack-objects", NULL };
  11 static const char *keep_packer[] = {
  12         "index-pack", "--stdin", "--fix-thin", NULL
  13 };
  14
  15 static int report_status;
  16 static int keep_pack;
  17
  18 static char capabilities[] = "report-status keep-pack";
  19 static int capabilities_sent;
  20
  21 static int show_ref(const char *path, const unsigned char *sha1)
  22 {
  23         if (capabilities_sent)
  24                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
  25         else
  26                 packet_write(1, "%s %s%c%s\n",
  27                              sha1_to_hex(sha1), path, 0, capabilities);
  28         capabilities_sent = 1;
  29         return 0;
  30 }
  31
  32 static void write_head_info(void)
  33 {
  34         for_each_ref(show_ref);
  35         if (!capabilities_sent)
  36                 show_ref("capabilities^{}", null_sha1);
  37
  38 }
  39
  40 struct command {
  41         struct command *next;
  42         const char *error_string;
  43         unsigned char old_sha1[20];
  44         unsigned char new_sha1[20];
  45         char ref_name[FLEX_ARRAY]; /* more */
  46 };
  47
  48 static struct command *commands;
  49
  50 static int is_all_zeroes(const char *hex)
  51 {
  52         int i;
  53         for (i = 0; i < 40; i++)
  54                 if (*hex++ != '0')
  55                         return 0;
  56         return 1;
  57 }
  58
  59 static int verify_old_ref(const char *name, char *hex_contents)
  60 {
  61         int fd, ret;
  62         char buffer[60];
  63
  64         if (is_all_zeroes(hex_contents))
  65                 return 0;
  66         fd = open(name, O_RDONLY);
  67         if (fd < 0)
  68                 return -1;
  69         ret = read(fd, buffer, 40);
  70         close(fd);
  71         if (ret != 40)
  72                 return -1;
  73         if (memcmp(buffer, hex_contents, 40))
  74                 return -1;
  75         return 0;
  76 }
  77
  78 static char update_hook[] = "hooks/update";
  79
  80 static int run_update_hook(const char *refname,
  81                            char *old_hex, char *new_hex)
  82 {
  83         int code;
  84
  85         if (access(update_hook, X_OK) < 0)
  86                 return 0;
  87         code = run_command(update_hook, refname, old_hex, new_hex, NULL);
  88         switch (code) {
  89         case 0:
  90                 return 0;
  91         case -ERR_RUN_COMMAND_FORK:
  92                 return error("hook fork failed");
  93         case -ERR_RUN_COMMAND_EXEC:
  94                 return error("hook execute failed");
  95         case -ERR_RUN_COMMAND_WAITPID:
  96                 return error("waitpid failed");
  97         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
  98                 return error("waitpid is confused");
  99         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
 100                 return error("%s died of signal", update_hook);
 101         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
 102                 return error("%s died strangely", update_hook);
 103         default:
 104                 error("%s exited with error code %d", update_hook, -code);
 105                 return -code;
 106         }
 107 }
 108
 109 static int update(struct command *cmd)
 110 {
 111         const char *name = cmd->ref_name;
 112         unsigned char *old_sha1 = cmd->old_sha1;
 113         unsigned char *new_sha1 = cmd->new_sha1;
 114         char new_hex[60], *old_hex, *lock_name;
 115         int newfd, namelen, written;
 116
 117         cmd->error_string = NULL;
 118         if (!strncmp(name, "refs/", 5) && check_ref_format(name + 5)) {
 119                 cmd->error_string = "funny refname";
 120                 return error("refusing to create funny ref '%s' locally",
 121                              name);
 122         }
 123
 124         namelen = strlen(name);
 125         lock_name = xmalloc(namelen + 10);
 126         memcpy(lock_name, name, namelen);
 127         memcpy(lock_name + namelen, ".lock", 6);
 128
 129         strcpy(new_hex, sha1_to_hex(new_sha1));
 130         old_hex = sha1_to_hex(old_sha1);
 131         if (!has_sha1_file(new_sha1)) {
 132                 cmd->error_string = "bad pack";
 133                 return error("unpack should have generated %s, "
 134                              "but I can't find it!", new_hex);
 135         }
 136         if (deny_non_fast_forwards && !is_null_sha1(old_sha1)) {
 137                 struct commit *old_commit, *new_commit;
 138                 struct commit_list *bases, *ent;
 139
 140                 old_commit = (struct commit *)parse_object(old_sha1);
 141                 new_commit = (struct commit *)parse_object(new_sha1);
 142                 bases = get_merge_bases(old_commit, new_commit, 1);
 143                 for (ent = bases; ent; ent = ent->next)
 144                         if (!hashcmp(old_sha1, ent->item->object.sha1))
 145                                 break;
 146                 free_commit_list(bases);
 147                 if (!ent)
 148                         return error("denying non-fast forward;"
 149                                      " you should pull first");
 150         }
 151         safe_create_leading_directories(lock_name);
 152
 153         newfd = open(lock_name, O_CREAT | O_EXCL | O_WRONLY, 0666);
 154         if (newfd < 0) {
 155                 cmd->error_string = "can't lock";
 156                 return error("unable to create %s (%s)",
 157                              lock_name, strerror(errno));
 158         }
 159
 160         /* Write the ref with an ending '\n' */
 161         new_hex[40] = '\n';
 162         new_hex[41] = 0;
 163         written = write(newfd, new_hex, 41);
 164         /* Remove the '\n' again */
 165         new_hex[40] = 0;
 166
 167         close(newfd);
 168         if (written != 41) {
 169                 unlink(lock_name);
 170                 cmd->error_string = "can't write";
 171                 return error("unable to write %s", lock_name);
 172         }
 173         if (verify_old_ref(name, old_hex) < 0) {
 174                 unlink(lock_name);
 175                 cmd->error_string = "raced";
 176                 return error("%s changed during push", name);
 177         }
 178         if (run_update_hook(name, old_hex, new_hex)) {
 179                 unlink(lock_name);
 180                 cmd->error_string = "hook declined";
 181                 return error("hook declined to update %s", name);
 182         }
 183         else if (rename(lock_name, name) < 0) {
 184                 unlink(lock_name);
 185                 cmd->error_string = "can't rename";
 186                 return error("unable to replace %s", name);
 187         }
 188         else {
 189                 fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
 190                 return 0;
 191         }
 192 }
 193
 194 static char update_post_hook[] = "hooks/post-update";
 195
 196 static void run_update_post_hook(struct command *cmd)
 197 {
 198         struct command *cmd_p;
 199         int argc;
 200         const char **argv;
 201
 202         if (access(update_post_hook, X_OK) < 0)
 203                 return;
 204         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
 205                 if (cmd_p->error_string)
 206                         continue;
 207                 argc++;
 208         }
 209         argv = xmalloc(sizeof(*argv) * (1 + argc));
 210         argv[0] = update_post_hook;
 211
 212         for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
 213                 char *p;
 214                 if (cmd_p->error_string)
 215                         continue;
 216                 p = xmalloc(strlen(cmd_p->ref_name) + 1);
 217                 strcpy(p, cmd_p->ref_name);
 218                 argv[argc] = p;
 219                 argc++;
 220         }
 221         argv[argc] = NULL;
 222         run_command_v_opt(argc, argv, RUN_COMMAND_NO_STDIO);
 223 }
 224
 225 /*
 226  * This gets called after(if) we've successfully
 227  * unpacked the data payload.
 228  */
 229 static void execute_commands(void)
 230 {
 231         struct command *cmd = commands;
 232
 233         while (cmd) {
 234                 update(cmd);
 235                 cmd = cmd->next;
 236         }
 237         run_update_post_hook(commands);
 238 }
 239
 240 static void read_head_info(void)
 241 {
 242         struct command **p = &commands;
 243         for (;;) {
 244                 static char line[1000];
 245                 unsigned char old_sha1[20], new_sha1[20];
 246                 struct command *cmd;
 247                 char *refname;
 248                 int len, reflen;
 249
 250                 len = packet_read_line(0, line, sizeof(line));
 251                 if (!len)
 252                         break;
 253                 if (line[len-1] == '\n')
 254                         line[--len] = 0;
 255                 if (len < 83 ||
 256                     line[40] != ' ' ||
 257                     line[81] != ' ' ||
 258                     get_sha1_hex(line, old_sha1) ||
 259                     get_sha1_hex(line + 41, new_sha1))
 260                         die("protocol error: expected old/new/ref, got '%s'",
 261                             line);
 262
 263                 refname = line + 82;
 264                 reflen = strlen(refname);
 265                 if (reflen + 82 < len) {
 266                         if (strstr(refname + reflen + 1, "report-status"))
 267                                 report_status = 1;
 268                         if (strstr(refname + reflen + 1, "keep-pack"))
 269                                 keep_pack = 1;
 270                 }
 271                 cmd = xmalloc(sizeof(struct command) + len - 80);
 272                 hashcpy(cmd->old_sha1, old_sha1);
 273                 hashcpy(cmd->new_sha1, new_sha1);
 274                 memcpy(cmd->ref_name, line + 82, len - 81);
 275                 cmd->error_string = "n/a (unpacker error)";
 276                 cmd->next = NULL;
 277                 *p = cmd;
 278                 p = &cmd->next;
 279         }
 280 }
 281
 282 static const char *unpack(int *error_code)
 283 {
 284         int code;
 285
 286         if (keep_pack)
 287                 code = run_command_v_opt(ARRAY_SIZE(keep_packer) - 1,
 288                                          keep_packer, RUN_GIT_CMD);
 289         else
 290                 code = run_command_v_opt(ARRAY_SIZE(unpacker) - 1,
 291                                          unpacker, RUN_GIT_CMD);
 292
 293         *error_code = 0;
 294         switch (code) {
 295         case 0:
 296                 return NULL;
 297         case -ERR_RUN_COMMAND_FORK:
 298                 return "unpack fork failed";
 299         case -ERR_RUN_COMMAND_EXEC:
 300                 return "unpack execute failed";
 301         case -ERR_RUN_COMMAND_WAITPID:
 302                 return "waitpid failed";
 303         case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
 304                 return "waitpid is confused";
 305         case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
 306                 return "unpacker died of signal";
 307         case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
 308                 return "unpacker died strangely";
 309         default:
 310                 *error_code = -code;
 311                 return "unpacker exited with error code";
 312         }
 313 }
 314
 315 static void report(const char *unpack_status)
 316 {
 317         struct command *cmd;
 318         packet_write(1, "unpack %s\n",
 319                      unpack_status ? unpack_status : "ok");
 320         for (cmd = commands; cmd; cmd = cmd->next) {
 321                 if (!cmd->error_string)
 322                         packet_write(1, "ok %s\n",
 323                                      cmd->ref_name);
 324                 else
 325                         packet_write(1, "ng %s %s\n",
 326                                      cmd->ref_name, cmd->error_string);
 327         }
 328         packet_flush(1);
 329 }
 330
 331 int main(int argc, char **argv)
 332 {
 333         int i;
 334         char *dir = NULL;
 335
 336         argv++;
 337         for (i = 1; i < argc; i++) {
 338                 char *arg = *argv++;
 339
 340                 if (*arg == '-') {
 341                         /* Do flag handling here */
 342                         usage(receive_pack_usage);
 343                 }
 344                 if (dir)
 345                         usage(receive_pack_usage);
 346                 dir = arg;
 347         }
 348         if (!dir)
 349                 usage(receive_pack_usage);
 350
 351         if (!enter_repo(dir, 0))
 352                 die("'%s': unable to chdir or not a git archive", dir);
 353
 354         write_head_info();
 355
 356         /* EOF */
 357         packet_flush(1);
 358
 359         read_head_info();
 360         if (commands) {
 361                 int code;
 362                 const char *unpack_status = unpack(&code);
 363                 if (!unpack_status)
 364                         execute_commands();
 365                 if (report_status)
 366                         report(unpack_status);
 367         }
 368         return 0;
 369 }