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 const char *msg;
  18
  19 /*
  20  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  21  * and append the result to arg.  Return a pointer to the terminator.
  22  * Die if there is an error in how the argument is C-quoted.  This
  23  * function is only used if not -z.
  24  */
  25 static const char *parse_arg(const char *next, struct strbuf *arg)
  26 {
  27         if (*next == '"') {
  28                 const char *orig = next;
  29
  30                 if (unquote_c_style(arg, next, &next))
  31                         die("badly quoted argument: %s", orig);
  32                 if (*next && !isspace(*next))
  33                         die("unexpected character after quoted argument: %s", orig);
  34         } else {
  35                 while (*next && !isspace(*next))
  36                         strbuf_addch(arg, *next++);
  37         }
  38
  39         return next;
  40 }
  41
  42 /*
  43  * Parse the reference name immediately after "command SP".  If not
  44  * -z, then handle C-quoting.  Return a pointer to a newly allocated
  45  * string containing the name of the reference, or NULL if there was
  46  * an error.  Update *next to point at the character that terminates
  47  * the argument.  Die if C-quoting is malformed or the reference name
  48  * is invalid.
  49  */
  50 static char *parse_refname(struct strbuf *input, const char **next)
  51 {
  52         struct strbuf ref = STRBUF_INIT;
  53
  54         if (line_termination) {
  55                 /* Without -z, use the next argument */
  56                 *next = parse_arg(*next, &ref);
  57         } else {
  58                 /* With -z, use everything up to the next NUL */
  59                 strbuf_addstr(&ref, *next);
  60                 *next += ref.len;
  61         }
  62
  63         if (!ref.len) {
  64                 strbuf_release(&ref);
  65                 return NULL;
  66         }
  67
  68         if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  69                 die("invalid ref format: %s", ref.buf);
  70
  71         return strbuf_detach(&ref, NULL);
  72 }
  73
  74 /*
  75  * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
  76  * difference affects which error messages are generated):
  77  */
  78 #define PARSE_SHA1_OLD 0x01
  79
  80 /*
  81  * For backwards compatibility, accept an empty string for update's
  82  * <newvalue> in binary mode to be equivalent to specifying zeros.
  83  */
  84 #define PARSE_SHA1_ALLOW_EMPTY 0x02
  85
  86 /*
  87  * Parse an argument separator followed by the next argument, if any.
  88  * If there is an argument, convert it to a SHA-1, write it to sha1,
  89  * set *next to point at the character terminating the argument, and
  90  * return 0.  If there is no argument at all (not even the empty
  91  * string), return 1 and leave *next unchanged.  If the value is
  92  * provided but cannot be converted to a SHA-1, die.  flags can
  93  * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
  94  */
  95 static int parse_next_sha1(struct strbuf *input, const char **next,
  96                            unsigned char *sha1,
  97                            const char *command, const char *refname,
  98                            int flags)
  99 {
 100         struct strbuf arg = STRBUF_INIT;
 101         int ret = 0;
 102
 103         if (*next == input->buf + input->len)
 104                 goto eof;
 105
 106         if (line_termination) {
 107                 /* Without -z, consume SP and use next argument */
 108                 if (!**next || **next == line_termination)
 109                         return 1;
 110                 if (**next != ' ')
 111                         die("%s %s: expected SP but got: %s",
 112                             command, refname, *next);
 113                 (*next)++;
 114                 *next = parse_arg(*next, &arg);
 115                 if (arg.len) {
 116                         if (get_sha1(arg.buf, sha1))
 117                                 goto invalid;
 118                 } else {
 119                         /* Without -z, an empty value means all zeros: */
 120                         hashclr(sha1);
 121                 }
 122         } else {
 123                 /* With -z, read the next NUL-terminated line */
 124                 if (**next)
 125                         die("%s %s: expected NUL but got: %s",
 126                             command, refname, *next);
 127                 (*next)++;
 128                 if (*next == input->buf + input->len)
 129                         goto eof;
 130                 strbuf_addstr(&arg, *next);
 131                 *next += arg.len;
 132
 133                 if (arg.len) {
 134                         if (get_sha1(arg.buf, sha1))
 135                                 goto invalid;
 136                 } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 137                         /* With -z, treat an empty value as all zeros: */
 138                         warning("%s %s: missing <newvalue>, treating as zero",
 139                                 command, refname);
 140                         hashclr(sha1);
 141                 } else {
 142                         /*
 143                          * With -z, an empty non-required value means
 144                          * unspecified:
 145                          */
 146                         ret = 1;
 147                 }
 148         }
 149
 150         strbuf_release(&arg);
 151
 152         return ret;
 153
 154  invalid:
 155         die(flags & PARSE_SHA1_OLD ?
 156             "%s %s: invalid <oldvalue>: %s" :
 157             "%s %s: invalid <newvalue>: %s",
 158             command, refname, arg.buf);
 159
 160  eof:
 161         die(flags & PARSE_SHA1_OLD ?
 162             "%s %s: unexpected end of input when reading <oldvalue>" :
 163             "%s %s: unexpected end of input when reading <newvalue>",
 164             command, refname);
 165 }
 166
 167
 168 /*
 169  * The following five parse_cmd_*() functions parse the corresponding
 170  * command.  In each case, next points at the character following the
 171  * command name and the following space.  They each return a pointer
 172  * to the character terminating the command, and die with an
 173  * explanatory message if there are any parsing problems.  All of
 174  * these functions handle either text or binary format input,
 175  * depending on how line_termination is set.
 176  */
 177
 178 static const char *parse_cmd_update(struct ref_transaction *transaction,
 179                                     struct strbuf *input, const char *next)
 180 {
 181         struct strbuf err = STRBUF_INIT;
 182         char *refname;
 183         unsigned char new_sha1[20];
 184         unsigned char old_sha1[20];
 185         int have_old;
 186
 187         refname = parse_refname(input, &next);
 188         if (!refname)
 189                 die("update: missing <ref>");
 190
 191         if (parse_next_sha1(input, &next, new_sha1, "update", refname,
 192                             PARSE_SHA1_ALLOW_EMPTY))
 193                 die("update %s: missing <newvalue>", refname);
 194
 195         have_old = !parse_next_sha1(input, &next, old_sha1, "update", refname,
 196                                     PARSE_SHA1_OLD);
 197
 198         if (*next != line_termination)
 199                 die("update %s: extra input: %s", refname, next);
 200
 201         if (ref_transaction_update(transaction, refname,
 202                                    new_sha1, have_old ? old_sha1 : NULL,
 203                                    update_flags, msg, &err))
 204                 die("%s", err.buf);
 205
 206         update_flags = 0;
 207         free(refname);
 208         strbuf_release(&err);
 209
 210         return next;
 211 }
 212
 213 static const char *parse_cmd_create(struct ref_transaction *transaction,
 214                                     struct strbuf *input, const char *next)
 215 {
 216         struct strbuf err = STRBUF_INIT;
 217         char *refname;
 218         unsigned char new_sha1[20];
 219
 220         refname = parse_refname(input, &next);
 221         if (!refname)
 222                 die("create: missing <ref>");
 223
 224         if (parse_next_sha1(input, &next, new_sha1, "create", refname, 0))
 225                 die("create %s: missing <newvalue>", refname);
 226
 227         if (is_null_sha1(new_sha1))
 228                 die("create %s: zero <newvalue>", refname);
 229
 230         if (*next != line_termination)
 231                 die("create %s: extra input: %s", refname, next);
 232
 233         if (ref_transaction_create(transaction, refname, new_sha1,
 234                                    update_flags, msg, &err))
 235                 die("%s", err.buf);
 236
 237         update_flags = 0;
 238         free(refname);
 239         strbuf_release(&err);
 240
 241         return next;
 242 }
 243
 244 static const char *parse_cmd_delete(struct ref_transaction *transaction,
 245                                     struct strbuf *input, const char *next)
 246 {
 247         struct strbuf err = STRBUF_INIT;
 248         char *refname;
 249         unsigned char old_sha1[20];
 250         int have_old;
 251
 252         refname = parse_refname(input, &next);
 253         if (!refname)
 254                 die("delete: missing <ref>");
 255
 256         if (parse_next_sha1(input, &next, old_sha1, "delete", refname,
 257                             PARSE_SHA1_OLD)) {
 258                 have_old = 0;
 259         } else {
 260                 if (is_null_sha1(old_sha1))
 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_sha1 : NULL,
 270                                    update_flags, msg, &err))
 271                 die("%s", err.buf);
 272
 273         update_flags = 0;
 274         free(refname);
 275         strbuf_release(&err);
 276
 277         return next;
 278 }
 279
 280 static const char *parse_cmd_verify(struct ref_transaction *transaction,
 281                                     struct strbuf *input, const char *next)
 282 {
 283         struct strbuf err = STRBUF_INIT;
 284         char *refname;
 285         unsigned char old_sha1[20];
 286
 287         refname = parse_refname(input, &next);
 288         if (!refname)
 289                 die("verify: missing <ref>");
 290
 291         if (parse_next_sha1(input, &next, old_sha1, "verify", refname,
 292                             PARSE_SHA1_OLD))
 293                 hashclr(old_sha1);
 294
 295         if (*next != line_termination)
 296                 die("verify %s: extra input: %s", refname, next);
 297
 298         if (ref_transaction_verify(transaction, refname, old_sha1,
 299                                    update_flags, &err))
 300                 die("%s", err.buf);
 301
 302         update_flags = 0;
 303         free(refname);
 304         strbuf_release(&err);
 305
 306         return next;
 307 }
 308
 309 static const char *parse_cmd_option(struct strbuf *input, const char *next)
 310 {
 311         if (!strncmp(next, "no-deref", 8) && next[8] == line_termination)
 312                 update_flags |= REF_NODEREF;
 313         else
 314                 die("option unknown: %s", next);
 315         return next + 8;
 316 }
 317
 318 static void update_refs_stdin(struct ref_transaction *transaction)
 319 {
 320         struct strbuf input = STRBUF_INIT;
 321         const char *next;
 322
 323         if (strbuf_read(&input, 0, 1000) < 0)
 324                 die_errno("could not read from stdin");
 325         next = input.buf;
 326         /* Read each line dispatch its command */
 327         while (next < input.buf + input.len) {
 328                 if (*next == line_termination)
 329                         die("empty command in input");
 330                 else if (isspace(*next))
 331                         die("whitespace before command: %s", next);
 332                 else if (starts_with(next, "update "))
 333                         next = parse_cmd_update(transaction, &input, next + 7);
 334                 else if (starts_with(next, "create "))
 335                         next = parse_cmd_create(transaction, &input, next + 7);
 336                 else if (starts_with(next, "delete "))
 337                         next = parse_cmd_delete(transaction, &input, next + 7);
 338                 else if (starts_with(next, "verify "))
 339                         next = parse_cmd_verify(transaction, &input, next + 7);
 340                 else if (starts_with(next, "option "))
 341                         next = parse_cmd_option(&input, next + 7);
 342                 else
 343                         die("unknown command: %s", next);
 344
 345                 next++;
 346         }
 347
 348         strbuf_release(&input);
 349 }
 350
 351 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 352 {
 353         const char *refname, *oldval;
 354         unsigned char sha1[20], oldsha1[20];
 355         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 356         unsigned int flags = 0;
 357         struct option options[] = {
 358                 OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 359                 OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 360                 OPT_BOOL( 0 , "no-deref", &no_deref,
 361                                         N_("update <refname> not the one it points to")),
 362                 OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 363                 OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 364                 OPT_END(),
 365         };
 366
 367         git_config(git_default_config, NULL);
 368         argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 369                              0);
 370         if (msg && !*msg)
 371                 die("Refusing to perform update with empty message.");
 372
 373         if (read_stdin) {
 374                 struct strbuf err = STRBUF_INIT;
 375                 struct ref_transaction *transaction;
 376
 377                 transaction = ref_transaction_begin(&err);
 378                 if (!transaction)
 379                         die("%s", err.buf);
 380                 if (delete || no_deref || argc > 0)
 381                         usage_with_options(git_update_ref_usage, options);
 382                 if (end_null)
 383                         line_termination = '\0';
 384                 update_refs_stdin(transaction);
 385                 if (ref_transaction_commit(transaction, &err))
 386                         die("%s", err.buf);
 387                 ref_transaction_free(transaction);
 388                 strbuf_release(&err);
 389                 return 0;
 390         }
 391
 392         if (end_null)
 393                 usage_with_options(git_update_ref_usage, options);
 394
 395         if (delete) {
 396                 if (argc < 1 || argc > 2)
 397                         usage_with_options(git_update_ref_usage, options);
 398                 refname = argv[0];
 399                 oldval = argv[1];
 400         } else {
 401                 const char *value;
 402                 if (argc < 2 || argc > 3)
 403                         usage_with_options(git_update_ref_usage, options);
 404                 refname = argv[0];
 405                 value = argv[1];
 406                 oldval = argv[2];
 407                 if (get_sha1(value, sha1))
 408                         die("%s: not a valid SHA1", value);
 409         }
 410
 411         hashclr(oldsha1); /* all-zero hash in case oldval is the empty string */
 412         if (oldval && *oldval && get_sha1(oldval, oldsha1))
 413                 die("%s: not a valid old SHA1", oldval);
 414
 415         if (no_deref)
 416                 flags = REF_NODEREF;
 417         if (delete)
 418                 return delete_ref(refname, oldval ? oldsha1 : NULL, flags);
 419         else
 420                 return update_ref(msg, refname, sha1, oldval ? oldsha1 : NULL,
 421                                   flags, UPDATE_REFS_DIE_ON_ERR);
 422 }