builtin/update-ref.c

   1 #include "builtin.h"
   2 #include "config.h"
   3 #include "gettext.h"
   4 #include "hash.h"
   5 #include "refs.h"
   6 #include "object-name.h"
   7 #include "parse-options.h"
   8 #include "quote.h"
   9 #include "repository.h"
  10
  11 static const char * const git_update_ref_usage[] = {
  12         N_("git update-ref [<options>] -d <refname> [<old-val>]"),
  13         N_("git update-ref [<options>]    <refname> <new-val> [<old-val>]"),
  14         N_("git update-ref [<options>] --stdin [-z]"),
  15         NULL
  16 };
  17
  18 static char line_termination = '\n';
  19 static unsigned int update_flags;
  20 static unsigned int default_flags;
  21 static unsigned create_reflog_flag;
  22 static const char *msg;
  23
  24 /*
  25  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  26  * and append the result to arg.  Return a pointer to the terminator.
  27  * Die if there is an error in how the argument is C-quoted.  This
  28  * function is only used if not -z.
  29  */
  30 static const char *parse_arg(const char *next, struct strbuf *arg)
  31 {
  32         if (*next == '"') {
  33                 const char *orig = next;
  34
  35                 if (unquote_c_style(arg, next, &next))
  36                         die("badly quoted argument: %s", orig);
  37                 if (*next && !isspace(*next))
  38                         die("unexpected character after quoted argument: %s", orig);
  39         } else {
  40                 while (*next && !isspace(*next))
  41                         strbuf_addch(arg, *next++);
  42         }
  43
  44         return next;
  45 }
  46
  47 /*
  48  * Parse the reference name immediately after "command SP".  If not
  49  * -z, then handle C-quoting.  Return a pointer to a newly allocated
  50  * string containing the name of the reference, or NULL if there was
  51  * an error.  Update *next to point at the character that terminates
  52  * the argument.  Die if C-quoting is malformed or the reference name
  53  * is invalid.
  54  */
  55 static char *parse_refname(const char **next)
  56 {
  57         struct strbuf ref = STRBUF_INIT;
  58
  59         if (line_termination) {
  60                 /* Without -z, use the next argument */
  61                 *next = parse_arg(*next, &ref);
  62         } else {
  63                 /* With -z, use everything up to the next NUL */
  64                 strbuf_addstr(&ref, *next);
  65                 *next += ref.len;
  66         }
  67
  68         if (!ref.len) {
  69                 strbuf_release(&ref);
  70                 return NULL;
  71         }
  72
  73         if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  74                 die("invalid ref format: %s", ref.buf);
  75
  76         return strbuf_detach(&ref, NULL);
  77 }
  78
  79 /*
  80  * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
  81  * difference affects which error messages are generated):
  82  */
  83 #define PARSE_SHA1_OLD 0x01
  84
  85 /*
  86  * For backwards compatibility, accept an empty string for update's
  87  * <newvalue> in binary mode to be equivalent to specifying zeros.
  88  */
  89 #define PARSE_SHA1_ALLOW_EMPTY 0x02
  90
  91 /*
  92  * Parse an argument separator followed by the next argument, if any.
  93  * If there is an argument, convert it to a SHA-1, write it to sha1,
  94  * set *next to point at the character terminating the argument, and
  95  * return 0.  If there is no argument at all (not even the empty
  96  * string), return 1 and leave *next unchanged.  If the value is
  97  * provided but cannot be converted to a SHA-1, die.  flags can
  98  * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
  99  */
 100 static int parse_next_oid(const char **next, const char *end,
 101                           struct object_id *oid,
 102                           const char *command, const char *refname,
 103                           int flags)
 104 {
 105         struct strbuf arg = STRBUF_INIT;
 106         int ret = 0;
 107
 108         if (*next == end)
 109                 goto eof;
 110
 111         if (line_termination) {
 112                 /* Without -z, consume SP and use next argument */
 113                 if (!**next || **next == line_termination)
 114                         return 1;
 115                 if (**next != ' ')
 116                         die("%s %s: expected SP but got: %s",
 117                             command, refname, *next);
 118                 (*next)++;
 119                 *next = parse_arg(*next, &arg);
 120                 if (arg.len) {
 121                         if (repo_get_oid(the_repository, arg.buf, oid))
 122                                 goto invalid;
 123                 } else {
 124                         /* Without -z, an empty value means all zeros: */
 125                         oidclr(oid);
 126                 }
 127         } else {
 128                 /* With -z, read the next NUL-terminated line */
 129                 if (**next)
 130                         die("%s %s: expected NUL but got: %s",
 131                             command, refname, *next);
 132                 (*next)++;
 133                 if (*next == end)
 134                         goto eof;
 135                 strbuf_addstr(&arg, *next);
 136                 *next += arg.len;
 137
 138                 if (arg.len) {
 139                         if (repo_get_oid(the_repository, arg.buf, oid))
 140                                 goto invalid;
 141                 } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 142                         /* With -z, treat an empty value as all zeros: */
 143                         warning("%s %s: missing <newvalue>, treating as zero",
 144                                 command, refname);
 145                         oidclr(oid);
 146                 } else {
 147                         /*
 148                          * With -z, an empty non-required value means
 149                          * unspecified:
 150                          */
 151                         ret = 1;
 152                 }
 153         }
 154
 155         strbuf_release(&arg);
 156
 157         return ret;
 158
 159  invalid:
 160         die(flags & PARSE_SHA1_OLD ?
 161             "%s %s: invalid <oldvalue>: %s" :
 162             "%s %s: invalid <newvalue>: %s",
 163             command, refname, arg.buf);
 164
 165  eof:
 166         die(flags & PARSE_SHA1_OLD ?
 167             "%s %s: unexpected end of input when reading <oldvalue>" :
 168             "%s %s: unexpected end of input when reading <newvalue>",
 169             command, refname);
 170 }
 171
 172
 173 /*
 174  * The following five parse_cmd_*() functions parse the corresponding
 175  * command.  In each case, next points at the character following the
 176  * command name and the following space.  They each return a pointer
 177  * to the character terminating the command, and die with an
 178  * explanatory message if there are any parsing problems.  All of
 179  * these functions handle either text or binary format input,
 180  * depending on how line_termination is set.
 181  */
 182
 183 static void parse_cmd_update(struct ref_transaction *transaction,
 184                              const char *next, const char *end)
 185 {
 186         struct strbuf err = STRBUF_INIT;
 187         char *refname;
 188         struct object_id new_oid, old_oid;
 189         int have_old;
 190
 191         refname = parse_refname(&next);
 192         if (!refname)
 193                 die("update: missing <ref>");
 194
 195         if (parse_next_oid(&next, end, &new_oid, "update", refname,
 196                            PARSE_SHA1_ALLOW_EMPTY))
 197                 die("update %s: missing <newvalue>", refname);
 198
 199         have_old = !parse_next_oid(&next, end, &old_oid, "update", refname,
 200                                    PARSE_SHA1_OLD);
 201
 202         if (*next != line_termination)
 203                 die("update %s: extra input: %s", refname, next);
 204
 205         if (ref_transaction_update(transaction, refname,
 206                                    &new_oid, have_old ? &old_oid : NULL,
 207                                    update_flags | create_reflog_flag,
 208                                    msg, &err))
 209                 die("%s", err.buf);
 210
 211         update_flags = default_flags;
 212         free(refname);
 213         strbuf_release(&err);
 214 }
 215
 216 static void parse_cmd_create(struct ref_transaction *transaction,
 217                              const char *next, const char *end)
 218 {
 219         struct strbuf err = STRBUF_INIT;
 220         char *refname;
 221         struct object_id new_oid;
 222
 223         refname = parse_refname(&next);
 224         if (!refname)
 225                 die("create: missing <ref>");
 226
 227         if (parse_next_oid(&next, end, &new_oid, "create", refname, 0))
 228                 die("create %s: missing <newvalue>", refname);
 229
 230         if (is_null_oid(&new_oid))
 231                 die("create %s: zero <newvalue>", refname);
 232
 233         if (*next != line_termination)
 234                 die("create %s: extra input: %s", refname, next);
 235
 236         if (ref_transaction_create(transaction, refname, &new_oid,
 237                                    update_flags | create_reflog_flag,
 238                                    msg, &err))
 239                 die("%s", err.buf);
 240
 241         update_flags = default_flags;
 242         free(refname);
 243         strbuf_release(&err);
 244 }
 245
 246 static void parse_cmd_delete(struct ref_transaction *transaction,
 247                              const char *next, const char *end)
 248 {
 249         struct strbuf err = STRBUF_INIT;
 250         char *refname;
 251         struct object_id old_oid;
 252         int have_old;
 253
 254         refname = parse_refname(&next);
 255         if (!refname)
 256                 die("delete: missing <ref>");
 257
 258         if (parse_next_oid(&next, end, &old_oid, "delete", refname,
 259                            PARSE_SHA1_OLD)) {
 260                 have_old = 0;
 261         } else {
 262                 if (is_null_oid(&old_oid))
 263                         die("delete %s: zero <oldvalue>", refname);
 264                 have_old = 1;
 265         }
 266
 267         if (*next != line_termination)
 268                 die("delete %s: extra input: %s", refname, next);
 269
 270         if (ref_transaction_delete(transaction, refname,
 271                                    have_old ? &old_oid : NULL,
 272                                    update_flags, msg, &err))
 273                 die("%s", err.buf);
 274
 275         update_flags = default_flags;
 276         free(refname);
 277         strbuf_release(&err);
 278 }
 279
 280 static void parse_cmd_verify(struct ref_transaction *transaction,
 281                              const char *next, const char *end)
 282 {
 283         struct strbuf err = STRBUF_INIT;
 284         char *refname;
 285         struct object_id old_oid;
 286
 287         refname = parse_refname(&next);
 288         if (!refname)
 289                 die("verify: missing <ref>");
 290
 291         if (parse_next_oid(&next, end, &old_oid, "verify", refname,
 292                            PARSE_SHA1_OLD))
 293                 oidclr(&old_oid);
 294
 295         if (*next != line_termination)
 296                 die("verify %s: extra input: %s", refname, next);
 297
 298         if (ref_transaction_verify(transaction, refname, &old_oid,
 299                                    update_flags, &err))
 300                 die("%s", err.buf);
 301
 302         update_flags = default_flags;
 303         free(refname);
 304         strbuf_release(&err);
 305 }
 306
 307 static void report_ok(const char *command)
 308 {
 309         fprintf(stdout, "%s: ok\n", command);
 310         fflush(stdout);
 311 }
 312
 313 static void parse_cmd_option(struct ref_transaction *transaction UNUSED,
 314                              const char *next, const char *end UNUSED)
 315 {
 316         const char *rest;
 317         if (skip_prefix(next, "no-deref", &rest) && *rest == line_termination)
 318                 update_flags |= REF_NO_DEREF;
 319         else
 320                 die("option unknown: %s", next);
 321 }
 322
 323 static void parse_cmd_start(struct ref_transaction *transaction UNUSED,
 324                             const char *next, const char *end UNUSED)
 325 {
 326         if (*next != line_termination)
 327                 die("start: extra input: %s", next);
 328         report_ok("start");
 329 }
 330
 331 static void parse_cmd_prepare(struct ref_transaction *transaction,
 332                               const char *next, const char *end UNUSED)
 333 {
 334         struct strbuf error = STRBUF_INIT;
 335         if (*next != line_termination)
 336                 die("prepare: extra input: %s", next);
 337         if (ref_transaction_prepare(transaction, &error))
 338                 die("prepare: %s", error.buf);
 339         report_ok("prepare");
 340 }
 341
 342 static void parse_cmd_abort(struct ref_transaction *transaction,
 343                             const char *next, const char *end UNUSED)
 344 {
 345         struct strbuf error = STRBUF_INIT;
 346         if (*next != line_termination)
 347                 die("abort: extra input: %s", next);
 348         if (ref_transaction_abort(transaction, &error))
 349                 die("abort: %s", error.buf);
 350         report_ok("abort");
 351 }
 352
 353 static void parse_cmd_commit(struct ref_transaction *transaction,
 354                              const char *next, const char *end UNUSED)
 355 {
 356         struct strbuf error = STRBUF_INIT;
 357         if (*next != line_termination)
 358                 die("commit: extra input: %s", next);
 359         if (ref_transaction_commit(transaction, &error))
 360                 die("commit: %s", error.buf);
 361         report_ok("commit");
 362         ref_transaction_free(transaction);
 363 }
 364
 365 enum update_refs_state {
 366         /* Non-transactional state open for updates. */
 367         UPDATE_REFS_OPEN,
 368         /* A transaction has been started. */
 369         UPDATE_REFS_STARTED,
 370         /* References are locked and ready for commit */
 371         UPDATE_REFS_PREPARED,
 372         /* Transaction has been committed or closed. */
 373         UPDATE_REFS_CLOSED,
 374 };
 375
 376 static const struct parse_cmd {
 377         const char *prefix;
 378         void (*fn)(struct ref_transaction *, const char *, const char *);
 379         unsigned args;
 380         enum update_refs_state state;
 381 } command[] = {
 382         { "update",  parse_cmd_update,  3, UPDATE_REFS_OPEN },
 383         { "create",  parse_cmd_create,  2, UPDATE_REFS_OPEN },
 384         { "delete",  parse_cmd_delete,  2, UPDATE_REFS_OPEN },
 385         { "verify",  parse_cmd_verify,  2, UPDATE_REFS_OPEN },
 386         { "option",  parse_cmd_option,  1, UPDATE_REFS_OPEN },
 387         { "start",   parse_cmd_start,   0, UPDATE_REFS_STARTED },
 388         { "prepare", parse_cmd_prepare, 0, UPDATE_REFS_PREPARED },
 389         { "abort",   parse_cmd_abort,   0, UPDATE_REFS_CLOSED },
 390         { "commit",  parse_cmd_commit,  0, UPDATE_REFS_CLOSED },
 391 };
 392
 393 static void update_refs_stdin(void)
 394 {
 395         struct strbuf input = STRBUF_INIT, err = STRBUF_INIT;
 396         enum update_refs_state state = UPDATE_REFS_OPEN;
 397         struct ref_transaction *transaction;
 398         int i, j;
 399
 400         transaction = ref_transaction_begin(&err);
 401         if (!transaction)
 402                 die("%s", err.buf);
 403
 404         /* Read each line dispatch its command */
 405         while (!strbuf_getwholeline(&input, stdin, line_termination)) {
 406                 const struct parse_cmd *cmd = NULL;
 407
 408                 if (*input.buf == line_termination)
 409                         die("empty command in input");
 410                 else if (isspace(*input.buf))
 411                         die("whitespace before command: %s", input.buf);
 412
 413                 for (i = 0; i < ARRAY_SIZE(command); i++) {
 414                         const char *prefix = command[i].prefix;
 415                         char c;
 416
 417                         if (!starts_with(input.buf, prefix))
 418                                 continue;
 419
 420                         /*
 421                          * If the command has arguments, verify that it's
 422                          * followed by a space. Otherwise, it shall be followed
 423                          * by a line terminator.
 424                          */
 425                         c = command[i].args ? ' ' : line_termination;
 426                         if (input.buf[strlen(prefix)] != c)
 427                                 continue;
 428
 429                         cmd = &command[i];
 430                         break;
 431                 }
 432                 if (!cmd)
 433                         die("unknown command: %s", input.buf);
 434
 435                 /*
 436                  * Read additional arguments if NUL-terminated. Do not raise an
 437                  * error in case there is an early EOF to let the command
 438                  * handle missing arguments with a proper error message.
 439                  */
 440                 for (j = 1; line_termination == '\0' && j < cmd->args; j++)
 441                         if (strbuf_appendwholeline(&input, stdin, line_termination))
 442                                 break;
 443
 444                 switch (state) {
 445                 case UPDATE_REFS_OPEN:
 446                 case UPDATE_REFS_STARTED:
 447                         if (state == UPDATE_REFS_STARTED && cmd->state == UPDATE_REFS_STARTED)
 448                                 die("cannot restart ongoing transaction");
 449                         /* Do not downgrade a transaction to a non-transaction. */
 450                         if (cmd->state >= state)
 451                                 state = cmd->state;
 452                         break;
 453                 case UPDATE_REFS_PREPARED:
 454                         if (cmd->state != UPDATE_REFS_CLOSED)
 455                                 die("prepared transactions can only be closed");
 456                         state = cmd->state;
 457                         break;
 458                 case UPDATE_REFS_CLOSED:
 459                         if (cmd->state != UPDATE_REFS_STARTED)
 460                                 die("transaction is closed");
 461
 462                         /*
 463                          * Open a new transaction if we're currently closed and
 464                          * get a "start".
 465                          */
 466                         state = cmd->state;
 467                         transaction = ref_transaction_begin(&err);
 468                         if (!transaction)
 469                                 die("%s", err.buf);
 470
 471                         break;
 472                 }
 473
 474                 cmd->fn(transaction, input.buf + strlen(cmd->prefix) + !!cmd->args,
 475                         input.buf + input.len);
 476         }
 477
 478         switch (state) {
 479         case UPDATE_REFS_OPEN:
 480                 /* Commit by default if no transaction was requested. */
 481                 if (ref_transaction_commit(transaction, &err))
 482                         die("%s", err.buf);
 483                 ref_transaction_free(transaction);
 484                 break;
 485         case UPDATE_REFS_STARTED:
 486         case UPDATE_REFS_PREPARED:
 487                 /* If using a transaction, we want to abort it. */
 488                 if (ref_transaction_abort(transaction, &err))
 489                         die("%s", err.buf);
 490                 break;
 491         case UPDATE_REFS_CLOSED:
 492                 /* Otherwise no need to do anything, the transaction was closed already. */
 493                 break;
 494         }
 495
 496         strbuf_release(&err);
 497         strbuf_release(&input);
 498 }
 499
 500 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 501 {
 502         const char *refname, *oldval;
 503         struct object_id oid, oldoid;
 504         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 505         int create_reflog = 0;
 506         struct option options[] = {
 507                 OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 508                 OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 509                 OPT_BOOL( 0 , "no-deref", &no_deref,
 510                                         N_("update <refname> not the one it points to")),
 511                 OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 512                 OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 513                 OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
 514                 OPT_END(),
 515         };
 516
 517         git_config(git_default_config, NULL);
 518         argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 519                              0);
 520         if (msg && !*msg)
 521                 die("Refusing to perform update with empty message.");
 522
 523         create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
 524
 525         if (no_deref) {
 526                 default_flags = REF_NO_DEREF;
 527                 update_flags = default_flags;
 528         }
 529
 530         if (read_stdin) {
 531                 if (delete || argc > 0)
 532                         usage_with_options(git_update_ref_usage, options);
 533                 if (end_null)
 534                         line_termination = '\0';
 535                 update_refs_stdin();
 536                 return 0;
 537         }
 538
 539         if (end_null)
 540                 usage_with_options(git_update_ref_usage, options);
 541
 542         if (delete) {
 543                 if (argc < 1 || argc > 2)
 544                         usage_with_options(git_update_ref_usage, options);
 545                 refname = argv[0];
 546                 oldval = argv[1];
 547         } else {
 548                 const char *value;
 549                 if (argc < 2 || argc > 3)
 550                         usage_with_options(git_update_ref_usage, options);
 551                 refname = argv[0];
 552                 value = argv[1];
 553                 oldval = argv[2];
 554                 if (repo_get_oid(the_repository, value, &oid))
 555                         die("%s: not a valid SHA1", value);
 556         }
 557
 558         if (oldval) {
 559                 if (!*oldval)
 560                         /*
 561                          * The empty string implies that the reference
 562                          * must not already exist:
 563                          */
 564                         oidclr(&oldoid);
 565                 else if (repo_get_oid(the_repository, oldval, &oldoid))
 566                         die("%s: not a valid old SHA1", oldval);
 567         }
 568
 569         if (delete)
 570                 /*
 571                  * For purposes of backwards compatibility, we treat
 572                  * NULL_SHA1 as "don't care" here:
 573                  */
 574                 return delete_ref(msg, refname,
 575                                   (oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
 576                                   default_flags);
 577         else
 578                 return update_ref(msg, refname, &oid, oldval ? &oldoid : NULL,
 579                                   default_flags | create_reflog_flag,
 580                                   UPDATE_REFS_DIE_ON_ERR);
 581 }