builtin/update-ref.c

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