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, new_sha1, old_sha1,
 202                                    update_flags, have_old, msg, &err))
 203                 die("%s", err.buf);
 204
 205         update_flags = 0;
 206         free(refname);
 207         strbuf_release(&err);
 208
 209         return next;
 210 }
 211
 212 static const char *parse_cmd_create(struct ref_transaction *transaction,
 213                                     struct strbuf *input, const char *next)
 214 {
 215         struct strbuf err = STRBUF_INIT;
 216         char *refname;
 217         unsigned char new_sha1[20];
 218
 219         refname = parse_refname(input, &next);
 220         if (!refname)
 221                 die("create: missing <ref>");
 222
 223         if (parse_next_sha1(input, &next, new_sha1, "create", refname, 0))
 224                 die("create %s: missing <newvalue>", refname);
 225
 226         if (is_null_sha1(new_sha1))
 227                 die("create %s: zero <newvalue>", refname);
 228
 229         if (*next != line_termination)
 230                 die("create %s: extra input: %s", refname, next);
 231
 232         if (ref_transaction_create(transaction, refname, new_sha1,
 233                                    update_flags, msg, &err))
 234                 die("%s", err.buf);
 235
 236         update_flags = 0;
 237         free(refname);
 238         strbuf_release(&err);
 239
 240         return next;
 241 }
 242
 243 static const char *parse_cmd_delete(struct ref_transaction *transaction,
 244                                     struct strbuf *input, const char *next)
 245 {
 246         struct strbuf err = STRBUF_INIT;
 247         char *refname;
 248         unsigned char old_sha1[20];
 249         int have_old;
 250
 251         refname = parse_refname(input, &next);
 252         if (!refname)
 253                 die("delete: missing <ref>");
 254
 255         if (parse_next_sha1(input, &next, old_sha1, "delete", refname,
 256                             PARSE_SHA1_OLD)) {
 257                 have_old = 0;
 258         } else {
 259                 if (is_null_sha1(old_sha1))
 260                         die("delete %s: zero <oldvalue>", refname);
 261                 have_old = 1;
 262         }
 263
 264         if (*next != line_termination)
 265                 die("delete %s: extra input: %s", refname, next);
 266
 267         if (ref_transaction_delete(transaction, refname, old_sha1,
 268                                    update_flags, have_old, msg, &err))
 269                 die("%s", err.buf);
 270
 271         update_flags = 0;
 272         free(refname);
 273         strbuf_release(&err);
 274
 275         return next;
 276 }
 277
 278 static const char *parse_cmd_verify(struct ref_transaction *transaction,
 279                                     struct strbuf *input, const char *next)
 280 {
 281         struct strbuf err = STRBUF_INIT;
 282         char *refname;
 283         unsigned char new_sha1[20];
 284         unsigned char old_sha1[20];
 285
 286         refname = parse_refname(input, &next);
 287         if (!refname)
 288                 die("verify: missing <ref>");
 289
 290         if (parse_next_sha1(input, &next, old_sha1, "verify", refname,
 291                             PARSE_SHA1_OLD))
 292                 hashclr(old_sha1);
 293
 294         hashcpy(new_sha1, old_sha1);
 295
 296         if (*next != line_termination)
 297                 die("verify %s: extra input: %s", refname, next);
 298
 299         if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
 300                                    update_flags, 1, msg, &err))
 301                 die("%s", err.buf);
 302
 303         update_flags = 0;
 304         free(refname);
 305         strbuf_release(&err);
 306
 307         return next;
 308 }
 309
 310 static const char *parse_cmd_option(struct strbuf *input, const char *next)
 311 {
 312         if (!strncmp(next, "no-deref", 8) && next[8] == line_termination)
 313                 update_flags |= REF_NODEREF;
 314         else
 315                 die("option unknown: %s", next);
 316         return next + 8;
 317 }
 318
 319 static void update_refs_stdin(struct ref_transaction *transaction)
 320 {
 321         struct strbuf input = STRBUF_INIT;
 322         const char *next;
 323
 324         if (strbuf_read(&input, 0, 1000) < 0)
 325                 die_errno("could not read from stdin");
 326         next = input.buf;
 327         /* Read each line dispatch its command */
 328         while (next < input.buf + input.len) {
 329                 if (*next == line_termination)
 330                         die("empty command in input");
 331                 else if (isspace(*next))
 332                         die("whitespace before command: %s", next);
 333                 else if (starts_with(next, "update "))
 334                         next = parse_cmd_update(transaction, &input, next + 7);
 335                 else if (starts_with(next, "create "))
 336                         next = parse_cmd_create(transaction, &input, next + 7);
 337                 else if (starts_with(next, "delete "))
 338                         next = parse_cmd_delete(transaction, &input, next + 7);
 339                 else if (starts_with(next, "verify "))
 340                         next = parse_cmd_verify(transaction, &input, next + 7);
 341                 else if (starts_with(next, "option "))
 342                         next = parse_cmd_option(&input, next + 7);
 343                 else
 344                         die("unknown command: %s", next);
 345
 346                 next++;
 347         }
 348
 349         strbuf_release(&input);
 350 }
 351
 352 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 353 {
 354         const char *refname, *oldval;
 355         unsigned char sha1[20], oldsha1[20];
 356         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0, 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 }