builtin/update-ref.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "builtin.h"
   4 #include "parse-options.h"
   5 #include "quote.h"
   6 #include "argv-array.h"
   7
   8 static const char * const git_update_ref_usage[] = {
   9         N_("git update-ref [<options>] -d <refname> [<old-val>]"),
  10         N_("git update-ref [<options>]    <refname> <new-val> [<old-val>]"),
  11         N_("git update-ref [<options>] --stdin [-z]"),
  12         NULL
  13 };
  14
  15 static char line_termination = '\n';
  16 static int update_flags;
  17 static unsigned create_reflog_flag;
  18 static const char *msg;
  19
  20 /*
  21  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  22  * and append the result to arg.  Return a pointer to the terminator.
  23  * Die if there is an error in how the argument is C-quoted.  This
  24  * function is only used if not -z.
  25  */
  26 static const char *parse_arg(const char *next, struct strbuf *arg)
  27 {
  28         if (*next == '"') {
  29                 const char *orig = next;
  30
  31                 if (unquote_c_style(arg, next, &next))
  32                         die("badly quoted argument: %s", orig);
  33                 if (*next && !isspace(*next))
  34                         die("unexpected character after quoted argument: %s", orig);
  35         } else {
  36                 while (*next && !isspace(*next))
  37                         strbuf_addch(arg, *next++);
  38         }
  39
  40         return next;
  41 }
  42
  43 static const char *skip_trailing_space(const char *next)
  44 {
  45         if (line_termination)
  46                 while (*next && *next != line_termination && isspace(*next))
  47                         next++;
  48         return next;
  49 }
  50
  51 /*
  52  * Parse the reference name immediately after "command SP".  If not
  53  * -z, then handle C-quoting.  Return a pointer to a newly allocated
  54  * string containing the name of the reference, or NULL if there was
  55  * an error.  Update *next to point at the character that terminates
  56  * the argument.  Die if C-quoting is malformed or the reference name
  57  * is invalid.
  58  */
  59 static char *parse_refname(struct strbuf *input, const char **next)
  60 {
  61         struct strbuf ref = STRBUF_INIT;
  62
  63         if (line_termination) {
  64                 /* Without -z, use the next argument */
  65                 *next = parse_arg(*next, &ref);
  66         } else {
  67                 /* With -z, use everything up to the next NUL */
  68                 strbuf_addstr(&ref, *next);
  69                 *next += ref.len;
  70         }
  71
  72         if (!ref.len) {
  73                 strbuf_release(&ref);
  74                 return NULL;
  75         }
  76
  77         if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  78                 die("invalid ref format: %s", ref.buf);
  79
  80         return strbuf_detach(&ref, NULL);
  81 }
  82
  83 /*
  84  * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
  85  * difference affects which error messages are generated):
  86  */
  87 #define PARSE_SHA1_OLD 0x01
  88
  89 /*
  90  * For backwards compatibility, accept an empty string for update's
  91  * <newvalue> in binary mode to be equivalent to specifying zeros.
  92  */
  93 #define PARSE_SHA1_ALLOW_EMPTY 0x02
  94
  95 /*
  96  * Parse an argument separator followed by the next argument, if any.
  97  * If there is an argument, convert it to a SHA-1, write it to sha1,
  98  * set *next to point at the character terminating the argument, and
  99  * return 0.  If there is no argument at all (not even the empty
 100  * string), return 1 and leave *next unchanged.  If the value is
 101  * provided but cannot be converted to a SHA-1, die.  flags can
 102  * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
 103  */
 104 static int parse_next_sha1(struct strbuf *input, const char **next,
 105                            unsigned char *sha1,
 106                            const char *command, const char *refname,
 107                            int flags)
 108 {
 109         struct strbuf arg = STRBUF_INIT;
 110         int ret = 0;
 111
 112         if (*next == input->buf + input->len)
 113                 goto eof;
 114
 115         if (line_termination) {
 116                 /* Without -z, consume SP and use next argument */
 117                 if (!**next || **next == line_termination)
 118                         return 1;
 119                 if (**next != ' ')
 120                         die("%s %s: expected SP but got: %s",
 121                             command, refname, *next);
 122                 (*next)++;
 123                 *next = parse_arg(*next, &arg);
 124                 if (arg.len) {
 125                         if (get_sha1(arg.buf, sha1))
 126                                 goto invalid;
 127                 } else {
 128                         /* Without -z, an empty value means all zeros: */
 129                         hashclr(sha1);
 130                 }
 131         } else {
 132                 /* With -z, read the next NUL-terminated line */
 133                 if (**next)
 134                         die("%s %s: expected NUL but got: %s",
 135                             command, refname, *next);
 136                 (*next)++;
 137                 if (*next == input->buf + input->len)
 138                         goto eof;
 139                 strbuf_addstr(&arg, *next);
 140                 *next += arg.len;
 141
 142                 if (arg.len) {
 143                         if (get_sha1(arg.buf, sha1))
 144                                 goto invalid;
 145                 } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 146                         /* With -z, treat an empty value as all zeros: */
 147                         warning("%s %s: missing <newvalue>, treating as zero",
 148                                 command, refname);
 149                         hashclr(sha1);
 150                 } else {
 151                         /*
 152                          * With -z, an empty non-required value means
 153                          * unspecified:
 154                          */
 155                         ret = 1;
 156                 }
 157         }
 158
 159         strbuf_release(&arg);
 160
 161         return ret;
 162
 163  invalid:
 164         die(flags & PARSE_SHA1_OLD ?
 165             "%s %s: invalid <oldvalue>: %s" :
 166             "%s %s: invalid <newvalue>: %s",
 167             command, refname, arg.buf);
 168
 169  eof:
 170         die(flags & PARSE_SHA1_OLD ?
 171             "%s %s: unexpected end of input when reading <oldvalue>" :
 172             "%s %s: unexpected end of input when reading <newvalue>",
 173             command, refname);
 174 }
 175
 176
 177 /*
 178  * The following five parse_cmd_*() functions parse the corresponding
 179  * command.  In each case, next points at the character following the
 180  * command name and the following space.  They each return a pointer
 181  * to the character terminating the command, and die with an
 182  * explanatory message if there are any parsing problems.  All of
 183  * these functions handle either text or binary format input,
 184  * depending on how line_termination is set.
 185  */
 186
 187 static const char *parse_cmd_update(struct ref_transaction *transaction,
 188                                     struct strbuf *input, const char *next)
 189 {
 190         struct strbuf err = STRBUF_INIT;
 191         char *refname;
 192         unsigned char new_sha1[20];
 193         unsigned char old_sha1[20];
 194         int have_old;
 195
 196         refname = parse_refname(input, &next);
 197         if (!refname)
 198                 die("update: missing <ref>");
 199
 200         if (parse_next_sha1(input, &next, new_sha1, "update", refname,
 201                             PARSE_SHA1_ALLOW_EMPTY))
 202                 die("update %s: missing <newvalue>", refname);
 203
 204         have_old = !parse_next_sha1(input, &next, old_sha1, "update", refname,
 205                                     PARSE_SHA1_OLD);
 206
 207         next = skip_trailing_space(next);
 208         if (*next != line_termination)
 209                 die("update %s: extra input: %s", refname, next);
 210
 211         if (ref_transaction_update(transaction, refname,
 212                                    new_sha1, have_old ? old_sha1 : NULL,
 213                                    update_flags | create_reflog_flag,
 214                                    msg, &err))
 215                 die("%s", err.buf);
 216
 217         update_flags = 0;
 218         free(refname);
 219         strbuf_release(&err);
 220
 221         return next;
 222 }
 223
 224 static const char *parse_cmd_create(struct ref_transaction *transaction,
 225                                     struct strbuf *input, const char *next)
 226 {
 227         struct strbuf err = STRBUF_INIT;
 228         char *refname;
 229         unsigned char new_sha1[20];
 230
 231         refname = parse_refname(input, &next);
 232         if (!refname)
 233                 die("create: missing <ref>");
 234
 235         if (parse_next_sha1(input, &next, new_sha1, "create", refname, 0))
 236                 die("create %s: missing <newvalue>", refname);
 237
 238         if (is_null_sha1(new_sha1))
 239                 die("create %s: zero <newvalue>", refname);
 240
 241         next = skip_trailing_space(next);
 242         if (*next != line_termination)
 243                 die("create %s: extra input: %s", refname, next);
 244
 245         if (ref_transaction_create(transaction, refname, new_sha1,
 246                                    update_flags | create_reflog_flag,
 247                                    msg, &err))
 248                 die("%s", err.buf);
 249
 250         update_flags = 0;
 251         free(refname);
 252         strbuf_release(&err);
 253
 254         return next;
 255 }
 256
 257 static const char *parse_cmd_delete(struct ref_transaction *transaction,
 258                                     struct strbuf *input, const char *next)
 259 {
 260         struct strbuf err = STRBUF_INIT;
 261         char *refname;
 262         unsigned char old_sha1[20];
 263         int have_old;
 264
 265         refname = parse_refname(input, &next);
 266         if (!refname)
 267                 die("delete: missing <ref>");
 268
 269         if (parse_next_sha1(input, &next, old_sha1, "delete", refname,
 270                             PARSE_SHA1_OLD)) {
 271                 have_old = 0;
 272         } else {
 273                 if (is_null_sha1(old_sha1))
 274                         die("delete %s: zero <oldvalue>", refname);
 275                 have_old = 1;
 276         }
 277
 278         if (*next != line_termination)
 279                 die("delete %s: extra input: %s", refname, next);
 280
 281         if (ref_transaction_delete(transaction, refname,
 282                                    have_old ? old_sha1 : NULL,
 283                                    update_flags, msg, &err))
 284                 die("%s", err.buf);
 285
 286         update_flags = 0;
 287         free(refname);
 288         strbuf_release(&err);
 289
 290         return next;
 291 }
 292
 293 static const char *parse_cmd_verify(struct ref_transaction *transaction,
 294                                     struct strbuf *input, const char *next)
 295 {
 296         struct strbuf err = STRBUF_INIT;
 297         char *refname;
 298         unsigned char old_sha1[20];
 299
 300         refname = parse_refname(input, &next);
 301         if (!refname)
 302                 die("verify: missing <ref>");
 303
 304         if (parse_next_sha1(input, &next, old_sha1, "verify", refname,
 305                             PARSE_SHA1_OLD))
 306                 hashclr(old_sha1);
 307
 308         if (*next != line_termination)
 309                 die("verify %s: extra input: %s", refname, next);
 310
 311         if (ref_transaction_verify(transaction, refname, old_sha1,
 312                                    update_flags, &err))
 313                 die("%s", err.buf);
 314
 315         update_flags = 0;
 316         free(refname);
 317         strbuf_release(&err);
 318
 319         return next;
 320 }
 321
 322 static const char *parse_cmd_option(struct strbuf *input, const char *next)
 323 {
 324         if (!strncmp(next, "no-deref", 8) && next[8] == line_termination)
 325                 update_flags |= REF_NODEREF;
 326         else
 327                 die("option unknown: %s", next);
 328         return next + 8;
 329 }
 330
 331 static void update_refs_stdin(struct ref_transaction *transaction)
 332 {
 333         struct strbuf input = STRBUF_INIT;
 334         const char *next;
 335
 336         if (strbuf_read(&input, 0, 1000) < 0)
 337                 die_errno("could not read from stdin");
 338         next = input.buf;
 339         /* Read each line dispatch its command */
 340         while (next < input.buf + input.len) {
 341                 if (*next == line_termination)
 342                         die("empty command in input");
 343                 else if (isspace(*next))
 344                         die("whitespace before command: %s", next);
 345                 else if (starts_with(next, "update "))
 346                         next = parse_cmd_update(transaction, &input, next + 7);
 347                 else if (starts_with(next, "create "))
 348                         next = parse_cmd_create(transaction, &input, next + 7);
 349                 else if (starts_with(next, "delete "))
 350                         next = parse_cmd_delete(transaction, &input, next + 7);
 351                 else if (starts_with(next, "verify "))
 352                         next = parse_cmd_verify(transaction, &input, next + 7);
 353                 else if (starts_with(next, "option "))
 354                         next = parse_cmd_option(&input, next + 7);
 355                 else
 356                         die("unknown command: %s", next);
 357
 358                 next++;
 359         }
 360
 361         strbuf_release(&input);
 362 }
 363
 364 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 365 {
 366         const char *refname, *oldval;
 367         unsigned char sha1[20], oldsha1[20];
 368         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 369         unsigned int flags = 0;
 370         int create_reflog = 0;
 371         struct option options[] = {
 372                 OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 373                 OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 374                 OPT_BOOL( 0 , "no-deref", &no_deref,
 375                                         N_("update <refname> not the one it points to")),
 376                 OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 377                 OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 378                 OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
 379                 OPT_END(),
 380         };
 381
 382         git_config(git_default_config, NULL);
 383         argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 384                              0);
 385         if (msg && !*msg)
 386                 die("Refusing to perform update with empty message.");
 387
 388         create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
 389
 390         if (read_stdin) {
 391                 struct strbuf err = STRBUF_INIT;
 392                 struct ref_transaction *transaction;
 393
 394                 transaction = ref_transaction_begin(&err);
 395                 if (!transaction)
 396                         die("%s", err.buf);
 397                 if (delete || no_deref || argc > 0)
 398                         usage_with_options(git_update_ref_usage, options);
 399                 if (end_null)
 400                         line_termination = '\0';
 401                 update_refs_stdin(transaction);
 402                 if (ref_transaction_commit(transaction, &err))
 403                         die("%s", err.buf);
 404                 ref_transaction_free(transaction);
 405                 strbuf_release(&err);
 406                 return 0;
 407         }
 408
 409         if (end_null)
 410                 usage_with_options(git_update_ref_usage, options);
 411
 412         if (delete) {
 413                 if (argc < 1 || argc > 2)
 414                         usage_with_options(git_update_ref_usage, options);
 415                 refname = argv[0];
 416                 oldval = argv[1];
 417         } else {
 418                 const char *value;
 419                 if (argc < 2 || argc > 3)
 420                         usage_with_options(git_update_ref_usage, options);
 421                 refname = argv[0];
 422                 value = argv[1];
 423                 oldval = argv[2];
 424                 if (get_sha1(value, sha1))
 425                         die("%s: not a valid SHA1", value);
 426         }
 427
 428         if (oldval) {
 429                 if (!*oldval)
 430                         /*
 431                          * The empty string implies that the reference
 432                          * must not already exist:
 433                          */
 434                         hashclr(oldsha1);
 435                 else if (get_sha1(oldval, oldsha1))
 436                         die("%s: not a valid old SHA1", oldval);
 437         }
 438
 439         if (no_deref)
 440                 flags = REF_NODEREF;
 441         if (delete)
 442                 /*
 443                  * For purposes of backwards compatibility, we treat
 444                  * NULL_SHA1 as "don't care" here:
 445                  */
 446                 return delete_ref(refname,
 447                                   (oldval && !is_null_sha1(oldsha1)) ? oldsha1 : NULL,
 448                                   flags);
 449         else
 450                 return update_ref(msg, refname, sha1, oldval ? oldsha1 : NULL,
 451                                   flags | create_reflog_flag,
 452                                   UPDATE_REFS_DIE_ON_ERR);
 453 }