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