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