Andrew's git - gitweb.git/blob

31cf27668df705ae0dda6d28a2e1e78d568a170d
   1#include "refs.h"
   2#include "cache.h"
   3
   4#include <errno.h>
   5
   6/* We allow "recursive" symbolic refs. Only within reason, though */
   7#define MAXDEPTH 5
   8
   9const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
  10{
  11        int depth = MAXDEPTH, len;
  12        char buffer[256];
  13
  14        for (;;) {
  15                struct stat st;
  16                char *buf;
  17                int fd;
  18
  19                if (--depth < 0)
  20                        return NULL;
  21
  22                /* Special case: non-existing file.
  23                 * Not having the refs/heads/new-branch is OK
  24                 * if we are writing into it, so is .git/HEAD
  25                 * that points at refs/heads/master still to be
  26                 * born.  It is NOT OK if we are resolving for
  27                 * reading.
  28                 */
  29                if (lstat(path, &st) < 0) {
  30                        if (reading || errno != ENOENT)
  31                                return NULL;
  32                        memset(sha1, 0, 20);
  33                        return path;
  34                }
  35
  36                /* Follow "normalized" - ie "refs/.." symlinks by hand */
  37                if (S_ISLNK(st.st_mode)) {
  38                        len = readlink(path, buffer, sizeof(buffer)-1);
  39                        if (len >= 5 && !memcmp("refs/", buffer, 5)) {
  40                                path = git_path("%.*s", len, buffer);
  41                                continue;
  42                        }
  43                }
  44
  45                /*
  46                 * Anything else, just open it and try to use it as
  47                 * a ref
  48                 */
  49                fd = open(path, O_RDONLY);
  50                if (fd < 0)
  51                        return NULL;
  52                len = read(fd, buffer, sizeof(buffer)-1);
  53                close(fd);
  54
  55                /*
  56                 * Is it a symbolic ref?
  57                 */
  58                if (len < 4 || memcmp("ref:", buffer, 4))
  59                        break;
  60                buf = buffer + 4;
  61                len -= 4;
  62                while (len && isspace(*buf))
  63                        buf++, len--;
  64                while (len && isspace(buf[len-1]))
  65                        buf[--len] = 0;
  66                path = git_path("%.*s", len, buf);
  67        }
  68        if (len < 40 || get_sha1_hex(buffer, sha1))
  69                return NULL;
  70        return path;
  71}
  72
  73int create_symref(const char *git_HEAD, const char *refs_heads_master)
  74{
  75        const char *lockpath;
  76        char ref[1000];
  77        int fd, len, written;
  78
  79#ifndef NO_SYMLINK_HEAD
  80        if (prefer_symlink_refs) {
  81                unlink(git_HEAD);
  82                if (!symlink(refs_heads_master, git_HEAD))
  83                        return 0;
  84                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
  85        }
  86#endif
  87
  88        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
  89        if (sizeof(ref) <= len) {
  90                error("refname too long: %s", refs_heads_master);
  91                return -1;
  92        }
  93        lockpath = mkpath("%s.lock", git_HEAD);
  94        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666); 
  95        written = write(fd, ref, len);
  96        close(fd);
  97        if (written != len) {
  98                unlink(lockpath);
  99                error("Unable to write to %s", lockpath);
 100                return -2;
 101        }
 102        if (rename(lockpath, git_HEAD) < 0) {
 103                unlink(lockpath);
 104                error("Unable to create %s", git_HEAD);
 105                return -3;
 106        }
 107        return 0;
 108}
 109
 110int read_ref(const char *filename, unsigned char *sha1)
 111{
 112        if (resolve_ref(filename, sha1, 1))
 113                return 0;
 114        return -1;
 115}
 116
 117static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1), int trim)
 118{
 119        int retval = 0;
 120        DIR *dir = opendir(git_path("%s", base));
 121
 122        if (dir) {
 123                struct dirent *de;
 124                int baselen = strlen(base);
 125                char *path = xmalloc(baselen + 257);
 126
 127                if (!strncmp(base, "./", 2)) {
 128                        base += 2;
 129                        baselen -= 2;
 130                }
 131                memcpy(path, base, baselen);
 132                if (baselen && base[baselen-1] != '/')
 133                        path[baselen++] = '/';
 134
 135                while ((de = readdir(dir)) != NULL) {
 136                        unsigned char sha1[20];
 137                        struct stat st;
 138                        int namelen;
 139
 140                        if (de->d_name[0] == '.')
 141                                continue;
 142                        namelen = strlen(de->d_name);
 143                        if (namelen > 255)
 144                                continue;
 145                        memcpy(path + baselen, de->d_name, namelen+1);
 146                        if (stat(git_path("%s", path), &st) < 0)
 147                                continue;
 148                        if (S_ISDIR(st.st_mode)) {
 149                                retval = do_for_each_ref(path, fn, trim);
 150                                if (retval)
 151                                        break;
 152                                continue;
 153                        }
 154                        if (read_ref(git_path("%s", path), sha1) < 0) {
 155                                error("%s points nowhere!", path);
 156                                continue;
 157                        }
 158                        if (!has_sha1_file(sha1)) {
 159                                error("%s does not point to a valid "
 160                                      "commit object!", path);
 161                                continue;
 162                        }
 163                        retval = fn(path + trim, sha1);
 164                        if (retval)
 165                                break;
 166                }
 167                free(path);
 168                closedir(dir);
 169        }
 170        return retval;
 171}
 172
 173int head_ref(int (*fn)(const char *path, const unsigned char *sha1))
 174{
 175        unsigned char sha1[20];
 176        if (!read_ref(git_path("HEAD"), sha1))
 177                return fn("HEAD", sha1);
 178        return 0;
 179}
 180
 181int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1))
 182{
 183        return do_for_each_ref("refs", fn, 0);
 184}
 185
 186int for_each_tag_ref(int (*fn)(const char *path, const unsigned char *sha1))
 187{
 188        return do_for_each_ref("refs/tags", fn, 10);
 189}
 190
 191int for_each_branch_ref(int (*fn)(const char *path, const unsigned char *sha1))
 192{
 193        return do_for_each_ref("refs/heads", fn, 11);
 194}
 195
 196int for_each_remote_ref(int (*fn)(const char *path, const unsigned char *sha1))
 197{
 198        return do_for_each_ref("refs/remotes", fn, 13);
 199}
 200
 201int get_ref_sha1(const char *ref, unsigned char *sha1)
 202{
 203        if (check_ref_format(ref))
 204                return -1;
 205        return read_ref(git_path("refs/%s", ref), sha1);
 206}
 207
 208/*
 209 * Make sure "ref" is something reasonable to have under ".git/refs/";
 210 * We do not like it if:
 211 *
 212 * - any path component of it begins with ".", or
 213 * - it has double dots "..", or
 214 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 215 * - it ends with a "/".
 216 */
 217
 218static inline int bad_ref_char(int ch)
 219{
 220        return (((unsigned) ch) <= ' ' ||
 221                ch == '~' || ch == '^' || ch == ':' ||
 222                /* 2.13 Pattern Matching Notation */
 223                ch == '?' || ch == '*' || ch == '[');
 224}
 225
 226int check_ref_format(const char *ref)
 227{
 228        int ch, level;
 229        const char *cp = ref;
 230
 231        level = 0;
 232        while (1) {
 233                while ((ch = *cp++) == '/')
 234                        ; /* tolerate duplicated slashes */
 235                if (!ch)
 236                        return -1; /* should not end with slashes */
 237
 238                /* we are at the beginning of the path component */
 239                if (ch == '.' || bad_ref_char(ch))
 240                        return -1;
 241
 242                /* scan the rest of the path component */
 243                while ((ch = *cp++) != 0) {
 244                        if (bad_ref_char(ch))
 245                                return -1;
 246                        if (ch == '/')
 247                                break;
 248                        if (ch == '.' && *cp == '.')
 249                                return -1;
 250                }
 251                level++;
 252                if (!ch) {
 253                        if (level < 2)
 254                                return -1; /* at least of form "heads/blah" */
 255                        return 0;
 256                }
 257        }
 258}
 259
 260static struct ref_lock* verify_lock(struct ref_lock *lock,
 261        const unsigned char *old_sha1, int mustexist)
 262{
 263        char buf[40];
 264        int nr, fd = open(lock->ref_file, O_RDONLY);
 265        if (fd < 0 && (mustexist || errno != ENOENT)) {
 266                error("Can't verify ref %s", lock->ref_file);
 267                unlock_ref(lock);
 268                return NULL;
 269        }
 270        nr = read(fd, buf, 40);
 271        close(fd);
 272        if (nr != 40 || get_sha1_hex(buf, lock->old_sha1) < 0) {
 273                error("Can't verify ref %s", lock->ref_file);
 274                unlock_ref(lock);
 275                return NULL;
 276        }
 277        if (memcmp(lock->old_sha1, old_sha1, 20)) {
 278                error("Ref %s is at %s but expected %s", lock->ref_file,
 279                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
 280                unlock_ref(lock);
 281                return NULL;
 282        }
 283        return lock;
 284}
 285
 286static struct ref_lock* lock_ref_sha1_basic(const char *path,
 287        int plen,
 288        const unsigned char *old_sha1, int mustexist)
 289{
 290        struct ref_lock *lock;
 291        struct stat st;
 292
 293        lock = xcalloc(1, sizeof(struct ref_lock));
 294        lock->lock_fd = -1;
 295
 296        plen = strlen(path) - plen;
 297        path = resolve_ref(path, lock->old_sha1, mustexist);
 298        if (!path) {
 299                error("Can't read ref %s", path);
 300                unlock_ref(lock);
 301                return NULL;
 302        }
 303
 304        lock->ref_file = strdup(path);
 305        lock->lock_file = strdup(mkpath("%s.lock", lock->ref_file));
 306        lock->log_file = strdup(git_path("logs/%s", lock->ref_file + plen));
 307        lock->force_write = !lstat(lock->ref_file, &st) || errno == ENOENT;
 308
 309        if (safe_create_leading_directories(lock->lock_file))
 310                die("unable to create directory for %s", lock->lock_file);
 311        lock->lock_fd = open(lock->lock_file,
 312                O_WRONLY | O_CREAT | O_EXCL, 0666);
 313        if (lock->lock_fd < 0) {
 314                error("Couldn't open lock file %s: %s",
 315                        lock->lock_file, strerror(errno));
 316                unlock_ref(lock);
 317                return NULL;
 318        }
 319
 320        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 321}
 322
 323struct ref_lock* lock_ref_sha1(const char *ref,
 324        const unsigned char *old_sha1, int mustexist)
 325{
 326        if (check_ref_format(ref))
 327                return NULL;
 328        return lock_ref_sha1_basic(git_path("refs/%s", ref),
 329                strlen(ref), old_sha1, mustexist);
 330}
 331
 332struct ref_lock* lock_any_ref_for_update(const char *ref,
 333        const unsigned char *old_sha1, int mustexist)
 334{
 335        return lock_ref_sha1_basic(git_path("%s", ref),
 336                strlen(ref), old_sha1, mustexist);
 337}
 338
 339void unlock_ref (struct ref_lock *lock)
 340{
 341        if (lock->lock_fd >= 0) {
 342                close(lock->lock_fd);
 343                unlink(lock->lock_file);
 344        }
 345        if (lock->ref_file)
 346                free(lock->ref_file);
 347        if (lock->lock_file)
 348                free(lock->lock_file);
 349        if (lock->log_file)
 350                free(lock->log_file);
 351        free(lock);
 352}
 353
 354static int log_ref_write(struct ref_lock *lock,
 355        const unsigned char *sha1, const char *msg)
 356{
 357        int logfd, written, oflags = O_APPEND | O_WRONLY;
 358        unsigned maxlen, len;
 359        char *logrec;
 360        const char *comitter;
 361
 362        if (log_all_ref_updates) {
 363                if (safe_create_leading_directories(lock->log_file) < 0)
 364                        return error("unable to create directory for %s",
 365                                lock->log_file);
 366                oflags |= O_CREAT;
 367        }
 368
 369        logfd = open(lock->log_file, oflags, 0666);
 370        if (logfd < 0) {
 371                if (!log_all_ref_updates && errno == ENOENT)
 372                        return 0;
 373                return error("Unable to append to %s: %s",
 374                        lock->log_file, strerror(errno));
 375        }
 376
 377        setup_ident();
 378        comitter = git_committer_info(1);
 379        if (msg) {
 380                maxlen = strlen(comitter) + strlen(msg) + 2*40 + 5;
 381                logrec = xmalloc(maxlen);
 382                len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
 383                        sha1_to_hex(lock->old_sha1),
 384                        sha1_to_hex(sha1),
 385                        comitter,
 386                        msg);
 387        } else {
 388                maxlen = strlen(comitter) + 2*40 + 4;
 389                logrec = xmalloc(maxlen);
 390                len = snprintf(logrec, maxlen, "%s %s %s\n",
 391                        sha1_to_hex(lock->old_sha1),
 392                        sha1_to_hex(sha1),
 393                        comitter);
 394        }
 395        written = len <= maxlen ? write(logfd, logrec, len) : -1;
 396        free(logrec);
 397        close(logfd);
 398        if (written != len)
 399                return error("Unable to append to %s", lock->log_file);
 400        return 0;
 401}
 402
 403int write_ref_sha1(struct ref_lock *lock,
 404        const unsigned char *sha1, const char *logmsg)
 405{
 406        static char term = '\n';
 407
 408        if (!lock)
 409                return -1;
 410        if (!lock->force_write && !memcmp(lock->old_sha1, sha1, 20)) {
 411                unlock_ref(lock);
 412                return 0;
 413        }
 414        if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
 415            write(lock->lock_fd, &term, 1) != 1
 416                || close(lock->lock_fd) < 0) {
 417                error("Couldn't write %s", lock->lock_file);
 418                unlock_ref(lock);
 419                return -1;
 420        }
 421        if (log_ref_write(lock, sha1, logmsg) < 0) {
 422                unlock_ref(lock);
 423                return -1;
 424        }
 425        if (rename(lock->lock_file, lock->ref_file) < 0) {
 426                error("Couldn't set %s", lock->ref_file);
 427                unlock_ref(lock);
 428                return -1;
 429        }
 430        lock->lock_fd = -1;
 431        unlock_ref(lock);
 432        return 0;
 433}
 434
 435int read_ref_at(const char *ref, unsigned long at_time, unsigned char *sha1)
 436{
 437        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
 438        char *tz_c;
 439        int logfd, tz;
 440        struct stat st;
 441        unsigned long date;
 442        unsigned char logged_sha1[20];
 443
 444        logfile = git_path("logs/%s", ref);
 445        logfd = open(logfile, O_RDONLY, 0);
 446        if (logfd < 0)
 447                die("Unable to read log %s: %s", logfile, strerror(errno));
 448        fstat(logfd, &st);
 449        if (!st.st_size)
 450                die("Log %s is empty.", logfile);
 451        logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
 452        close(logfd);
 453
 454        lastrec = NULL;
 455        rec = logend = logdata + st.st_size;
 456        while (logdata < rec) {
 457                if (logdata < rec && *(rec-1) == '\n')
 458                        rec--;
 459                lastgt = NULL;
 460                while (logdata < rec && *(rec-1) != '\n') {
 461                        rec--;
 462                        if (*rec == '>')
 463                                lastgt = rec;
 464                }
 465                if (!lastgt)
 466                        die("Log %s is corrupt.", logfile);
 467                date = strtoul(lastgt + 1, &tz_c, 10);
 468                if (date <= at_time) {
 469                        if (lastrec) {
 470                                if (get_sha1_hex(lastrec, logged_sha1))
 471                                        die("Log %s is corrupt.", logfile);
 472                                if (get_sha1_hex(rec + 41, sha1))
 473                                        die("Log %s is corrupt.", logfile);
 474                                if (memcmp(logged_sha1, sha1, 20)) {
 475                                        tz = strtoul(tz_c, NULL, 10);
 476                                        fprintf(stderr,
 477                                                "warning: Log %s has gap after %s.\n",
 478                                                logfile, show_rfc2822_date(date, tz));
 479                                }
 480                        } else if (date == at_time) {
 481                                if (get_sha1_hex(rec + 41, sha1))
 482                                        die("Log %s is corrupt.", logfile);
 483                        } else {
 484                                if (get_sha1_hex(rec + 41, logged_sha1))
 485                                        die("Log %s is corrupt.", logfile);
 486                                if (memcmp(logged_sha1, sha1, 20)) {
 487                                        tz = strtoul(tz_c, NULL, 10);
 488                                        fprintf(stderr,
 489                                                "warning: Log %s unexpectedly ended on %s.\n",
 490                                                logfile, show_rfc2822_date(date, tz));
 491                                }
 492                        }
 493                        munmap((void*)logdata, st.st_size);
 494                        return 0;
 495                }
 496                lastrec = rec;
 497        }
 498
 499        rec = logdata;
 500        while (rec < logend && *rec != '>' && *rec != '\n')
 501                rec++;
 502        if (rec == logend || *rec == '\n')
 503                die("Log %s is corrupt.", logfile);
 504        date = strtoul(rec + 1, &tz_c, 10);
 505        tz = strtoul(tz_c, NULL, 10);
 506        if (get_sha1_hex(logdata, sha1))
 507                die("Log %s is corrupt.", logfile);
 508        munmap((void*)logdata, st.st_size);
 509        fprintf(stderr, "warning: Log %s only goes back to %s.\n",
 510                logfile, show_rfc2822_date(date, tz));
 511        return 0;
 512}