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 #include "strvec.h"
  11
  12 static const char * const git_update_ref_usage[] = {
  13         N_("git update-ref [<options>] -d <refname> [<old-val>]"),
  14         N_("git update-ref [<options>]    <refname> <new-val> [<old-val>]"),
  15         N_("git update-ref [<options>] --stdin [-z]"),
  16         NULL
  17 };
  18
  19 static char line_termination = '\n';
  20 static unsigned int update_flags;
  21 static unsigned int default_flags;
  22 static unsigned create_reflog_flag;
  23 static const char *msg;
  24
  25 /*
  26  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  27  * and append the result to arg.  Return a pointer to the terminator.
  28  * Die if there is an error in how the argument is C-quoted.  This
  29  * function is only used if not -z.
  30  */
  31 static const char *parse_arg(const char *next, struct strbuf *arg)
  32 {
  33         if (*next == '"') {
  34                 const char *orig = next;
  35
  36                 if (unquote_c_style(arg, next, &next))
  37                         die("badly quoted argument: %s", orig);
  38                 if (*next && !isspace(*next))
  39                         die("unexpected character after quoted argument: %s", orig);
  40         } else {
  41                 while (*next && !isspace(*next))
  42                         strbuf_addch(arg, *next++);
  43         }
  44
  45         return next;
  46 }
  47
  48 /*
  49  * Parse the reference name immediately after "command SP".  If not
  50  * -z, then handle C-quoting.  Return a pointer to a newly allocated
  51  * string containing the name of the reference, or NULL if there was
  52  * an error.  Update *next to point at the character that terminates
  53  * the argument.  Die if C-quoting is malformed or the reference name
  54  * is invalid.
  55  */
  56 static char *parse_refname(const char **next)
  57 {
  58         struct strbuf ref = STRBUF_INIT;
  59
  60         if (line_termination) {
  61                 /* Without -z, use the next argument */
  62                 *next = parse_arg(*next, &ref);
  63         } else {
  64                 /* With -z, use everything up to the next NUL */
  65                 strbuf_addstr(&ref, *next);
  66                 *next += ref.len;
  67         }
  68
  69         if (!ref.len) {
  70                 strbuf_release(&ref);
  71                 return NULL;
  72         }
  73
  74         if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  75                 die("invalid ref format: %s", ref.buf);
  76
  77         return strbuf_detach(&ref, NULL);
  78 }
  79
  80 /*
  81  * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
  82  * difference affects which error messages are generated):
  83  */
  84 #define PARSE_SHA1_OLD 0x01
  85
  86 /*
  87  * For backwards compatibility, accept an empty string for update's
  88  * <newvalue> in binary mode to be equivalent to specifying zeros.
  89  */
  90 #define PARSE_SHA1_ALLOW_EMPTY 0x02
  91
  92 /*
  93  * Parse an argument separator followed by the next argument, if any.
  94  * If there is an argument, convert it to a SHA-1, write it to sha1,
  95  * set *next to point at the character terminating the argument, and
  96  * return 0.  If there is no argument at all (not even the empty
  97  * string), return 1 and leave *next unchanged.  If the value is
  98  * provided but cannot be converted to a SHA-1, die.  flags can
  99  * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
 100  */
 101 static int parse_next_oid(const char **next, const char *end,
 102                           struct object_id *oid,
 103                           const char *command, const char *refname,
 104                           int flags)
 105 {
 106         struct strbuf arg = STRBUF_INIT;
 107         int ret = 0;
 108
 109         if (*next == end)
 110                 goto eof;
 111
 112         if (line_termination) {
 113                 /* Without -z, consume SP and use next argument */
 114                 if (!**next || **next == line_termination)
 115                         return 1;
 116                 if (**next != ' ')
 117                         die("%s %s: expected SP but got: %s",
 118                             command, refname, *next);
 119                 (*next)++;
 120                 *next = parse_arg(*next, &arg);
 121                 if (arg.len) {
 122                         if (repo_get_oid(the_repository, arg.buf, oid))
 123                                 goto invalid;
 124                 } else {
 125                         /* Without -z, an empty value means all zeros: */
 126                         oidclr(oid);
 127                 }
 128         } else {
 129                 /* With -z, read the next NUL-terminated line */
 130                 if (**next)
 131                         die("%s %s: expected NUL but got: %s",
 132                             command, refname, *next);
 133                 (*next)++;
 134                 if (*next == end)
 135                         goto eof;
 136                 strbuf_addstr(&arg, *next);
 137                 *next += arg.len;
 138
 139                 if (arg.len) {
 140                         if (repo_get_oid(the_repository, arg.buf, oid))
 141                                 goto invalid;
 142                 } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 143                         /* With -z, treat an empty value as all zeros: */
 144                         warning("%s %s: missing <newvalue>, treating as zero",
 145                                 command, refname);
 146                         oidclr(oid);
 147                 } else {
 148                         /*
 149                          * With -z, an empty non-required value means
 150                          * unspecified:
 151                          */
 152                         ret = 1;
 153                 }
 154         }
 155
 156         strbuf_release(&arg);
 157
 158         return ret;
 159
 160  invalid:
 161         die(flags & PARSE_SHA1_OLD ?
 162             "%s %s: invalid <oldvalue>: %s" :
 163             "%s %s: invalid <newvalue>: %s",
 164             command, refname, arg.buf);
 165
 166  eof:
 167         die(flags & PARSE_SHA1_OLD ?
 168             "%s %s: unexpected end of input when reading <oldvalue>" :
 169             "%s %s: unexpected end of input when reading <newvalue>",
 170             command, refname);
 171 }
 172
 173
 174 /*
 175  * The following five parse_cmd_*() functions parse the corresponding
 176  * command.  In each case, next points at the character following the
 177  * command name and the following space.  They each return a pointer
 178  * to the character terminating the command, and die with an
 179  * explanatory message if there are any parsing problems.  All of
 180  * these functions handle either text or binary format input,
 181  * depending on how line_termination is set.
 182  */
 183
 184 static void parse_cmd_update(struct ref_transaction *transaction,
 185                              const char *next, const char *end)
 186 {
 187         struct strbuf err = STRBUF_INIT;
 188         char *refname;
 189         struct object_id new_oid, old_oid;
 190         int have_old;
 191
 192         refname = parse_refname(&next);
 193         if (!refname)
 194                 die("update: missing <ref>");
 195
 196         if (parse_next_oid(&next, end, &new_oid, "update", refname,
 197                            PARSE_SHA1_ALLOW_EMPTY))
 198                 die("update %s: missing <newvalue>", refname);
 199
 200         have_old = !parse_next_oid(&next, end, &old_oid, "update", refname,
 201                                    PARSE_SHA1_OLD);
 202
 203         if (*next != line_termination)
 204                 die("update %s: extra input: %s", refname, next);
 205
 206         if (ref_transaction_update(transaction, refname,
 207                                    &new_oid, have_old ? &old_oid : NULL,
 208                                    update_flags | create_reflog_flag,
 209                                    msg, &err))
 210                 die("%s", err.buf);
 211
 212         update_flags = default_flags;
 213         free(refname);
 214         strbuf_release(&err);
 215 }
 216
 217 static void parse_cmd_create(struct ref_transaction *transaction,
 218                              const char *next, const char *end)
 219 {
 220         struct strbuf err = STRBUF_INIT;
 221         char *refname;
 222         struct object_id new_oid;
 223
 224         refname = parse_refname(&next);
 225         if (!refname)
 226                 die("create: missing <ref>");
 227
 228         if (parse_next_oid(&next, end, &new_oid, "create", refname, 0))
 229                 die("create %s: missing <newvalue>", refname);
 230
 231         if (is_null_oid(&new_oid))
 232                 die("create %s: zero <newvalue>", refname);
 233
 234         if (*next != line_termination)
 235                 die("create %s: extra input: %s", refname, next);
 236
 237         if (ref_transaction_create(transaction, refname, &new_oid,
 238                                    update_flags | create_reflog_flag,
 239                                    msg, &err))
 240                 die("%s", err.buf);
 241
 242         update_flags = default_flags;
 243         free(refname);
 244         strbuf_release(&err);
 245 }
 246
 247 static void parse_cmd_delete(struct ref_transaction *transaction,
 248                              const char *next, const char *end)
 249 {
 250         struct strbuf err = STRBUF_INIT;
 251         char *refname;
 252         struct object_id old_oid;
 253         int have_old;
 254
 255         refname = parse_refname(&next);
 256         if (!refname)
 257                 die("delete: missing <ref>");
 258
 259         if (parse_next_oid(&next, end, &old_oid, "delete", refname,
 260                            PARSE_SHA1_OLD)) {
 261                 have_old = 0;
 262         } else {
 263                 if (is_null_oid(&old_oid))
 264                         die("delete %s: zero <oldvalue>", refname);
 265                 have_old = 1;
 266         }
 267
 268         if (*next != line_termination)
 269                 die("delete %s: extra input: %s", refname, next);
 270
 271         if (ref_transaction_delete(transaction, refname,
 272                                    have_old ? &old_oid : NULL,
 273                                    update_flags, msg, &err))
 274                 die("%s", err.buf);
 275
 276         update_flags = default_flags;
 277         free(refname);
 278         strbuf_release(&err);
 279 }
 280
 281 static void parse_cmd_verify(struct ref_transaction *transaction,
 282                              const char *next, const char *end)
 283 {
 284         struct strbuf err = STRBUF_INIT;
 285         char *refname;
 286         struct object_id old_oid;
 287
 288         refname = parse_refname(&next);
 289         if (!refname)
 290                 die("verify: missing <ref>");
 291
 292         if (parse_next_oid(&next, end, &old_oid, "verify", refname,
 293                            PARSE_SHA1_OLD))
 294                 oidclr(&old_oid);
 295
 296         if (*next != line_termination)
 297                 die("verify %s: extra input: %s", refname, next);
 298
 299         if (ref_transaction_verify(transaction, refname, &old_oid,
 300                                    update_flags, &err))
 301                 die("%s", err.buf);
 302
 303         update_flags = default_flags;
 304         free(refname);
 305         strbuf_release(&err);
 306 }
 307
 308 static void report_ok(const char *command)
 309 {
 310         fprintf(stdout, "%s: ok\n", command);
 311         fflush(stdout);
 312 }
 313
 314 static void parse_cmd_option(struct ref_transaction *transaction,
 315                              const char *next, const char *end)
 316 {
 317         const char *rest;
 318         if (skip_prefix(next, "no-deref", &rest) && *rest == line_termination)
 319                 update_flags |= REF_NO_DEREF;
 320         else
 321                 die("option unknown: %s", next);
 322 }
 323
 324 static void parse_cmd_start(struct ref_transaction *transaction,
 325                             const char *next, const char *end)
 326 {
 327         if (*next != line_termination)
 328                 die("start: extra input: %s", next);
 329         report_ok("start");
 330 }
 331
 332 static void parse_cmd_prepare(struct ref_transaction *transaction,
 333                               const char *next, const char *end)
 334 {
 335         struct strbuf error = STRBUF_INIT;
 336         if (*next != line_termination)
 337                 die("prepare: extra input: %s", next);
 338         if (ref_transaction_prepare(transaction, &error))
 339                 die("prepare: %s", error.buf);
 340         report_ok("prepare");
 341 }
 342
 343 static void parse_cmd_abort(struct ref_transaction *transaction,
 344                             const char *next, const char *end)
 345 {
 346         struct strbuf error = STRBUF_INIT;
 347         if (*next != line_termination)
 348                 die("abort: extra input: %s", next);
 349         if (ref_transaction_abort(transaction, &error))
 350                 die("abort: %s", error.buf);
 351         report_ok("abort");
 352 }
 353
 354 static void parse_cmd_commit(struct ref_transaction *transaction,
 355                              const char *next, const char *end)
 356 {
 357         struct strbuf error = STRBUF_INIT;
 358         if (*next != line_termination)
 359                 die("commit: extra input: %s", next);
 360         if (ref_transaction_commit(transaction, &error))
 361                 die("commit: %s", error.buf);
 362         report_ok("commit");
 363         ref_transaction_free(transaction);
 364 }
 365
 366 enum update_refs_state {
 367         /* Non-transactional state open for updates. */
 368         UPDATE_REFS_OPEN,
 369         /* A transaction has been started. */
 370         UPDATE_REFS_STARTED,
 371         /* References are locked and ready for commit */
 372         UPDATE_REFS_PREPARED,
 373         /* Transaction has been committed or closed. */
 374         UPDATE_REFS_CLOSED,
 375 };
 376
 377 static const struct parse_cmd {
 378         const char *prefix;
 379         void (*fn)(struct ref_transaction *, const char *, const char *);
 380         unsigned args;
 381         enum update_refs_state state;
 382 } command[] = {
 383         { "update",  parse_cmd_update,  3, UPDATE_REFS_OPEN },
 384         { "create",  parse_cmd_create,  2, UPDATE_REFS_OPEN },
 385         { "delete",  parse_cmd_delete,  2, UPDATE_REFS_OPEN },
 386         { "verify",  parse_cmd_verify,  2, UPDATE_REFS_OPEN },
 387         { "option",  parse_cmd_option,  1, UPDATE_REFS_OPEN },
 388         { "start",   parse_cmd_start,   0, UPDATE_REFS_STARTED },
 389         { "prepare", parse_cmd_prepare, 0, UPDATE_REFS_PREPARED },
 390         { "abort",   parse_cmd_abort,   0, UPDATE_REFS_CLOSED },
 391         { "commit",  parse_cmd_commit,  0, UPDATE_REFS_CLOSED },
 392 };
 393
 394 static void update_refs_stdin(void)
 395 {
 396         struct strbuf input = STRBUF_INIT, err = STRBUF_INIT;
 397         enum update_refs_state state = UPDATE_REFS_OPEN;
 398         struct ref_transaction *transaction;
 399         int i, j;
 400
 401         transaction = ref_transaction_begin(&err);
 402         if (!transaction)
 403                 die("%s", err.buf);
 404
 405         /* Read each line dispatch its command */
 406         while (!strbuf_getwholeline(&input, stdin, line_termination)) {
 407                 const struct parse_cmd *cmd = NULL;
 408
 409                 if (*input.buf == line_termination)
 410                         die("empty command in input");
 411                 else if (isspace(*input.buf))
 412                         die("whitespace before command: %s", input.buf);
 413
 414                 for (i = 0; i < ARRAY_SIZE(command); i++) {
 415                         const char *prefix = command[i].prefix;
 416                         char c;
 417
 418                         if (!starts_with(input.buf, prefix))
 419                                 continue;
 420
 421                         /*
 422                          * If the command has arguments, verify that it's
 423                          * followed by a space. Otherwise, it shall be followed
 424                          * by a line terminator.
 425                          */
 426                         c = command[i].args ? ' ' : line_termination;
 427                         if (input.buf[strlen(prefix)] != c)
 428                                 continue;
 429
 430                         cmd = &command[i];
 431                         break;
 432                 }
 433                 if (!cmd)
 434                         die("unknown command: %s", input.buf);
 435
 436                 /*
 437                  * Read additional arguments if NUL-terminated. Do not raise an
 438                  * error in case there is an early EOF to let the command
 439                  * handle missing arguments with a proper error message.
 440                  */
 441                 for (j = 1; line_termination == '\0' && j < cmd->args; j++)
 442                         if (strbuf_appendwholeline(&input, stdin, line_termination))
 443                                 break;
 444
 445                 switch (state) {
 446                 case UPDATE_REFS_OPEN:
 447                 case UPDATE_REFS_STARTED:
 448                         if (state == UPDATE_REFS_STARTED && cmd->state == UPDATE_REFS_STARTED)
 449                                 die("cannot restart ongoing transaction");
 450                         /* Do not downgrade a transaction to a non-transaction. */
 451                         if (cmd->state >= state)
 452                                 state = cmd->state;
 453                         break;
 454                 case UPDATE_REFS_PREPARED:
 455                         if (cmd->state != UPDATE_REFS_CLOSED)
 456                                 die("prepared transactions can only be closed");
 457                         state = cmd->state;
 458                         break;
 459                 case UPDATE_REFS_CLOSED:
 460                         if (cmd->state != UPDATE_REFS_STARTED)
 461                                 die("transaction is closed");
 462
 463                         /*
 464                          * Open a new transaction if we're currently closed and
 465                          * get a "start".
 466                          */
 467                         state = cmd->state;
 468                         transaction = ref_transaction_begin(&err);
 469                         if (!transaction)
 470                                 die("%s", err.buf);
 471
 472                         break;
 473                 }
 474
 475                 cmd->fn(transaction, input.buf + strlen(cmd->prefix) + !!cmd->args,
 476                         input.buf + input.len);
 477         }
 478
 479         switch (state) {
 480         case UPDATE_REFS_OPEN:
 481                 /* Commit by default if no transaction was requested. */
 482                 if (ref_transaction_commit(transaction, &err))
 483                         die("%s", err.buf);
 484                 ref_transaction_free(transaction);
 485                 break;
 486         case UPDATE_REFS_STARTED:
 487         case UPDATE_REFS_PREPARED:
 488                 /* If using a transaction, we want to abort it. */
 489                 if (ref_transaction_abort(transaction, &err))
 490                         die("%s", err.buf);
 491                 break;
 492         case UPDATE_REFS_CLOSED:
 493                 /* Otherwise no need to do anything, the transaction was closed already. */
 494                 break;
 495         }
 496
 497         strbuf_release(&err);
 498         strbuf_release(&input);
 499 }
 500
 501 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 502 {
 503         const char *refname, *oldval;
 504         struct object_id oid, oldoid;
 505         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 506         int create_reflog = 0;
 507         struct option options[] = {
 508                 OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 509                 OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 510                 OPT_BOOL( 0 , "no-deref", &no_deref,
 511                                         N_("update <refname> not the one it points to")),
 512                 OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 513                 OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 514                 OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
 515                 OPT_END(),
 516         };
 517
 518         git_config(git_default_config, NULL);
 519         argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 520                              0);
 521         if (msg && !*msg)
 522                 die("Refusing to perform update with empty message.");
 523
 524         create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
 525
 526         if (no_deref) {
 527                 default_flags = REF_NO_DEREF;
 528                 update_flags = default_flags;
 529         }
 530
 531         if (read_stdin) {
 532                 if (delete || argc > 0)
 533                         usage_with_options(git_update_ref_usage, options);
 534                 if (end_null)
 535                         line_termination = '\0';
 536                 update_refs_stdin();
 537                 return 0;
 538         }
 539
 540         if (end_null)
 541                 usage_with_options(git_update_ref_usage, options);
 542
 543         if (delete) {
 544                 if (argc < 1 || argc > 2)
 545                         usage_with_options(git_update_ref_usage, options);
 546                 refname = argv[0];
 547                 oldval = argv[1];
 548         } else {
 549                 const char *value;
 550                 if (argc < 2 || argc > 3)
 551                         usage_with_options(git_update_ref_usage, options);
 552                 refname = argv[0];
 553                 value = argv[1];
 554                 oldval = argv[2];
 555                 if (repo_get_oid(the_repository, value, &oid))
 556                         die("%s: not a valid SHA1", value);
 557         }
 558
 559         if (oldval) {
 560                 if (!*oldval)
 561                         /*
 562                          * The empty string implies that the reference
 563                          * must not already exist:
 564                          */
 565                         oidclr(&oldoid);
 566                 else if (repo_get_oid(the_repository, oldval, &oldoid))
 567                         die("%s: not a valid old SHA1", oldval);
 568         }
 569
 570         if (delete)
 571                 /*
 572                  * For purposes of backwards compatibility, we treat
 573                  * NULL_SHA1 as "don't care" here:
 574                  */
 575                 return delete_ref(msg, refname,
 576                                   (oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
 577                                   default_flags);
 578         else
 579                 return update_ref(msg, refname, &oid, oldval ? &oldoid : NULL,
 580                                   default_flags | create_reflog_flag,
 581                                   UPDATE_REFS_DIE_ON_ERR);
 582 }