wrapper.c

   1 /*
   2  * Various trivial helper wrappers around standard functions
   3  */
   4 #include "cache.h"
   5
   6 static void do_nothing(size_t size)
   7 {
   8 }
   9
  10 static void (*try_to_free_routine)(size_t size) = do_nothing;
  11
  12 static int memory_limit_check(size_t size, int gentle)
  13 {
  14         static size_t limit = 0;
  15         if (!limit) {
  16                 limit = git_env_ulong("GIT_ALLOC_LIMIT", 0);
  17                 if (!limit)
  18                         limit = SIZE_MAX;
  19         }
  20         if (size > limit) {
  21                 if (gentle) {
  22                         error("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
  23                               (uintmax_t)size, (uintmax_t)limit);
  24                         return -1;
  25                 } else
  26                         die("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
  27                             (uintmax_t)size, (uintmax_t)limit);
  28         }
  29         return 0;
  30 }
  31
  32 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
  33 {
  34         try_to_free_t old = try_to_free_routine;
  35         if (!routine)
  36                 routine = do_nothing;
  37         try_to_free_routine = routine;
  38         return old;
  39 }
  40
  41 char *xstrdup(const char *str)
  42 {
  43         char *ret = strdup(str);
  44         if (!ret) {
  45                 try_to_free_routine(strlen(str) + 1);
  46                 ret = strdup(str);
  47                 if (!ret)
  48                         die("Out of memory, strdup failed");
  49         }
  50         return ret;
  51 }
  52
  53 static void *do_xmalloc(size_t size, int gentle)
  54 {
  55         void *ret;
  56
  57         if (memory_limit_check(size, gentle))
  58                 return NULL;
  59         ret = malloc(size);
  60         if (!ret && !size)
  61                 ret = malloc(1);
  62         if (!ret) {
  63                 try_to_free_routine(size);
  64                 ret = malloc(size);
  65                 if (!ret && !size)
  66                         ret = malloc(1);
  67                 if (!ret) {
  68                         if (!gentle)
  69                                 die("Out of memory, malloc failed (tried to allocate %lu bytes)",
  70                                     (unsigned long)size);
  71                         else {
  72                                 error("Out of memory, malloc failed (tried to allocate %lu bytes)",
  73                                       (unsigned long)size);
  74                                 return NULL;
  75                         }
  76                 }
  77         }
  78 #ifdef XMALLOC_POISON
  79         memset(ret, 0xA5, size);
  80 #endif
  81         return ret;
  82 }
  83
  84 void *xmalloc(size_t size)
  85 {
  86         return do_xmalloc(size, 0);
  87 }
  88
  89 static void *do_xmallocz(size_t size, int gentle)
  90 {
  91         void *ret;
  92         if (unsigned_add_overflows(size, 1)) {
  93                 if (gentle) {
  94                         error("Data too large to fit into virtual memory space.");
  95                         return NULL;
  96                 } else
  97                         die("Data too large to fit into virtual memory space.");
  98         }
  99         ret = do_xmalloc(size + 1, gentle);
 100         if (ret)
 101                 ((char*)ret)[size] = 0;
 102         return ret;
 103 }
 104
 105 void *xmallocz(size_t size)
 106 {
 107         return do_xmallocz(size, 0);
 108 }
 109
 110 void *xmallocz_gently(size_t size)
 111 {
 112         return do_xmallocz(size, 1);
 113 }
 114
 115 /*
 116  * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
 117  * "data" to the allocated memory, zero terminates the allocated memory,
 118  * and returns a pointer to the allocated memory. If the allocation fails,
 119  * the program dies.
 120  */
 121 void *xmemdupz(const void *data, size_t len)
 122 {
 123         return memcpy(xmallocz(len), data, len);
 124 }
 125
 126 char *xstrndup(const char *str, size_t len)
 127 {
 128         char *p = memchr(str, '\0', len);
 129         return xmemdupz(str, p ? p - str : len);
 130 }
 131
 132 void *xrealloc(void *ptr, size_t size)
 133 {
 134         void *ret;
 135
 136         memory_limit_check(size, 0);
 137         ret = realloc(ptr, size);
 138         if (!ret && !size)
 139                 ret = realloc(ptr, 1);
 140         if (!ret) {
 141                 try_to_free_routine(size);
 142                 ret = realloc(ptr, size);
 143                 if (!ret && !size)
 144                         ret = realloc(ptr, 1);
 145                 if (!ret)
 146                         die("Out of memory, realloc failed");
 147         }
 148         return ret;
 149 }
 150
 151 void *xcalloc(size_t nmemb, size_t size)
 152 {
 153         void *ret;
 154
 155         memory_limit_check(size * nmemb, 0);
 156         ret = calloc(nmemb, size);
 157         if (!ret && (!nmemb || !size))
 158                 ret = calloc(1, 1);
 159         if (!ret) {
 160                 try_to_free_routine(nmemb * size);
 161                 ret = calloc(nmemb, size);
 162                 if (!ret && (!nmemb || !size))
 163                         ret = calloc(1, 1);
 164                 if (!ret)
 165                         die("Out of memory, calloc failed");
 166         }
 167         return ret;
 168 }
 169
 170 /*
 171  * Limit size of IO chunks, because huge chunks only cause pain.  OS X
 172  * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
 173  * the absence of bugs, large chunks can result in bad latencies when
 174  * you decide to kill the process.
 175  *
 176  * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
 177  * that is smaller than that, clip it to SSIZE_MAX, as a call to
 178  * read(2) or write(2) larger than that is allowed to fail.  As the last
 179  * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
 180  * to override this, if the definition of SSIZE_MAX given by the platform
 181  * is broken.
 182  */
 183 #ifndef MAX_IO_SIZE
 184 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
 185 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
 186 #  define MAX_IO_SIZE SSIZE_MAX
 187 # else
 188 #  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
 189 # endif
 190 #endif
 191
 192 /**
 193  * xopen() is the same as open(), but it die()s if the open() fails.
 194  */
 195 int xopen(const char *path, int oflag, ...)
 196 {
 197         mode_t mode = 0;
 198         va_list ap;
 199
 200         /*
 201          * va_arg() will have undefined behavior if the specified type is not
 202          * compatible with the argument type. Since integers are promoted to
 203          * ints, we fetch the next argument as an int, and then cast it to a
 204          * mode_t to avoid undefined behavior.
 205          */
 206         va_start(ap, oflag);
 207         if (oflag & O_CREAT)
 208                 mode = va_arg(ap, int);
 209         va_end(ap);
 210
 211         for (;;) {
 212                 int fd = open(path, oflag, mode);
 213                 if (fd >= 0)
 214                         return fd;
 215                 if (errno == EINTR)
 216                         continue;
 217
 218                 if ((oflag & O_RDWR) == O_RDWR)
 219                         die_errno(_("could not open '%s' for reading and writing"), path);
 220                 else if ((oflag & O_WRONLY) == O_WRONLY)
 221                         die_errno(_("could not open '%s' for writing"), path);
 222                 else
 223                         die_errno(_("could not open '%s' for reading"), path);
 224         }
 225 }
 226
 227 /*
 228  * xread() is the same a read(), but it automatically restarts read()
 229  * operations with a recoverable error (EAGAIN and EINTR). xread()
 230  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 231  */
 232 ssize_t xread(int fd, void *buf, size_t len)
 233 {
 234         ssize_t nr;
 235         if (len > MAX_IO_SIZE)
 236             len = MAX_IO_SIZE;
 237         while (1) {
 238                 nr = read(fd, buf, len);
 239                 if (nr < 0) {
 240                         if (errno == EINTR)
 241                                 continue;
 242                         if (errno == EAGAIN || errno == EWOULDBLOCK) {
 243                                 struct pollfd pfd;
 244                                 pfd.events = POLLIN;
 245                                 pfd.fd = fd;
 246                                 /* We deliberately ignore the return value */
 247                                 poll(&pfd, 1, -1);
 248                         }
 249                 }
 250                 return nr;
 251         }
 252 }
 253
 254 /*
 255  * xread_nonblock() is the same a read(), but it automatically restarts read()
 256  * interrupted operations (EINTR). xread_nonblock() DOES NOT GUARANTEE that
 257  * "len" bytes is read. EWOULDBLOCK is turned into EAGAIN.
 258  */
 259 ssize_t xread_nonblock(int fd, void *buf, size_t len)
 260 {
 261         ssize_t nr;
 262         if (len > MAX_IO_SIZE)
 263                 len = MAX_IO_SIZE;
 264         while (1) {
 265                 nr = read(fd, buf, len);
 266                 if (nr < 0) {
 267                         if (errno == EINTR)
 268                                 continue;
 269                         if (errno == EWOULDBLOCK)
 270                                 errno = EAGAIN;
 271                 }
 272                 return nr;
 273         }
 274 }
 275
 276 /*
 277  * xwrite() is the same a write(), but it automatically restarts write()
 278  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 279  * GUARANTEE that "len" bytes is written even if the operation is successful.
 280  */
 281 ssize_t xwrite(int fd, const void *buf, size_t len)
 282 {
 283         ssize_t nr;
 284         if (len > MAX_IO_SIZE)
 285             len = MAX_IO_SIZE;
 286         while (1) {
 287                 nr = write(fd, buf, len);
 288                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 289                         continue;
 290                 return nr;
 291         }
 292 }
 293
 294 /*
 295  * xpread() is the same as pread(), but it automatically restarts pread()
 296  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 297  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 298  */
 299 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 300 {
 301         ssize_t nr;
 302         if (len > MAX_IO_SIZE)
 303                 len = MAX_IO_SIZE;
 304         while (1) {
 305                 nr = pread(fd, buf, len, offset);
 306                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 307                         continue;
 308                 return nr;
 309         }
 310 }
 311
 312 ssize_t read_in_full(int fd, void *buf, size_t count)
 313 {
 314         char *p = buf;
 315         ssize_t total = 0;
 316
 317         while (count > 0) {
 318                 ssize_t loaded = xread(fd, p, count);
 319                 if (loaded < 0)
 320                         return -1;
 321                 if (loaded == 0)
 322                         return total;
 323                 count -= loaded;
 324                 p += loaded;
 325                 total += loaded;
 326         }
 327
 328         return total;
 329 }
 330
 331 ssize_t write_in_full(int fd, const void *buf, size_t count)
 332 {
 333         const char *p = buf;
 334         ssize_t total = 0;
 335
 336         while (count > 0) {
 337                 ssize_t written = xwrite(fd, p, count);
 338                 if (written < 0)
 339                         return -1;
 340                 if (!written) {
 341                         errno = ENOSPC;
 342                         return -1;
 343                 }
 344                 count -= written;
 345                 p += written;
 346                 total += written;
 347         }
 348
 349         return total;
 350 }
 351
 352 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 353 {
 354         char *p = buf;
 355         ssize_t total = 0;
 356
 357         while (count > 0) {
 358                 ssize_t loaded = xpread(fd, p, count, offset);
 359                 if (loaded < 0)
 360                         return -1;
 361                 if (loaded == 0)
 362                         return total;
 363                 count -= loaded;
 364                 p += loaded;
 365                 total += loaded;
 366                 offset += loaded;
 367         }
 368
 369         return total;
 370 }
 371
 372 int xdup(int fd)
 373 {
 374         int ret = dup(fd);
 375         if (ret < 0)
 376                 die_errno("dup failed");
 377         return ret;
 378 }
 379
 380 /**
 381  * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
 382  */
 383 FILE *xfopen(const char *path, const char *mode)
 384 {
 385         for (;;) {
 386                 FILE *fp = fopen(path, mode);
 387                 if (fp)
 388                         return fp;
 389                 if (errno == EINTR)
 390                         continue;
 391
 392                 if (*mode && mode[1] == '+')
 393                         die_errno(_("could not open '%s' for reading and writing"), path);
 394                 else if (*mode == 'w' || *mode == 'a')
 395                         die_errno(_("could not open '%s' for writing"), path);
 396                 else
 397                         die_errno(_("could not open '%s' for reading"), path);
 398         }
 399 }
 400
 401 FILE *xfdopen(int fd, const char *mode)
 402 {
 403         FILE *stream = fdopen(fd, mode);
 404         if (stream == NULL)
 405                 die_errno("Out of memory? fdopen failed");
 406         return stream;
 407 }
 408
 409 int xmkstemp(char *template)
 410 {
 411         int fd;
 412         char origtemplate[PATH_MAX];
 413         strlcpy(origtemplate, template, sizeof(origtemplate));
 414
 415         fd = mkstemp(template);
 416         if (fd < 0) {
 417                 int saved_errno = errno;
 418                 const char *nonrelative_template;
 419
 420                 if (strlen(template) != strlen(origtemplate))
 421                         template = origtemplate;
 422
 423                 nonrelative_template = absolute_path(template);
 424                 errno = saved_errno;
 425                 die_errno("Unable to create temporary file '%s'",
 426                         nonrelative_template);
 427         }
 428         return fd;
 429 }
 430
 431 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 432 int git_mkstemp(char *path, size_t len, const char *template)
 433 {
 434         const char *tmp;
 435         size_t n;
 436
 437         tmp = getenv("TMPDIR");
 438         if (!tmp)
 439                 tmp = "/tmp";
 440         n = snprintf(path, len, "%s/%s", tmp, template);
 441         if (len <= n) {
 442                 errno = ENAMETOOLONG;
 443                 return -1;
 444         }
 445         return mkstemp(path);
 446 }
 447
 448 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 449 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 450 {
 451         const char *tmp;
 452         size_t n;
 453
 454         tmp = getenv("TMPDIR");
 455         if (!tmp)
 456                 tmp = "/tmp";
 457         n = snprintf(path, len, "%s/%s", tmp, template);
 458         if (len <= n) {
 459                 errno = ENAMETOOLONG;
 460                 return -1;
 461         }
 462         return mkstemps(path, suffix_len);
 463 }
 464
 465 /* Adapted from libiberty's mkstemp.c. */
 466
 467 #undef TMP_MAX
 468 #define TMP_MAX 16384
 469
 470 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 471 {
 472         static const char letters[] =
 473                 "abcdefghijklmnopqrstuvwxyz"
 474                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 475                 "0123456789";
 476         static const int num_letters = 62;
 477         uint64_t value;
 478         struct timeval tv;
 479         char *template;
 480         size_t len;
 481         int fd, count;
 482
 483         len = strlen(pattern);
 484
 485         if (len < 6 + suffix_len) {
 486                 errno = EINVAL;
 487                 return -1;
 488         }
 489
 490         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 491                 errno = EINVAL;
 492                 return -1;
 493         }
 494
 495         /*
 496          * Replace pattern's XXXXXX characters with randomness.
 497          * Try TMP_MAX different filenames.
 498          */
 499         gettimeofday(&tv, NULL);
 500         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 501         template = &pattern[len - 6 - suffix_len];
 502         for (count = 0; count < TMP_MAX; ++count) {
 503                 uint64_t v = value;
 504                 /* Fill in the random bits. */
 505                 template[0] = letters[v % num_letters]; v /= num_letters;
 506                 template[1] = letters[v % num_letters]; v /= num_letters;
 507                 template[2] = letters[v % num_letters]; v /= num_letters;
 508                 template[3] = letters[v % num_letters]; v /= num_letters;
 509                 template[4] = letters[v % num_letters]; v /= num_letters;
 510                 template[5] = letters[v % num_letters]; v /= num_letters;
 511
 512                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 513                 if (fd >= 0)
 514                         return fd;
 515                 /*
 516                  * Fatal error (EPERM, ENOSPC etc).
 517                  * It doesn't make sense to loop.
 518                  */
 519                 if (errno != EEXIST)
 520                         break;
 521                 /*
 522                  * This is a random value.  It is only necessary that
 523                  * the next TMP_MAX values generated by adding 7777 to
 524                  * VALUE are different with (module 2^32).
 525                  */
 526                 value += 7777;
 527         }
 528         /* We return the null string if we can't find a unique file name.  */
 529         pattern[0] = '\0';
 530         return -1;
 531 }
 532
 533 int git_mkstemp_mode(char *pattern, int mode)
 534 {
 535         /* mkstemp is just mkstemps with no suffix */
 536         return git_mkstemps_mode(pattern, 0, mode);
 537 }
 538
 539 #ifdef NO_MKSTEMPS
 540 int gitmkstemps(char *pattern, int suffix_len)
 541 {
 542         return git_mkstemps_mode(pattern, suffix_len, 0600);
 543 }
 544 #endif
 545
 546 int xmkstemp_mode(char *template, int mode)
 547 {
 548         int fd;
 549         char origtemplate[PATH_MAX];
 550         strlcpy(origtemplate, template, sizeof(origtemplate));
 551
 552         fd = git_mkstemp_mode(template, mode);
 553         if (fd < 0) {
 554                 int saved_errno = errno;
 555                 const char *nonrelative_template;
 556
 557                 if (!template[0])
 558                         template = origtemplate;
 559
 560                 nonrelative_template = absolute_path(template);
 561                 errno = saved_errno;
 562                 die_errno("Unable to create temporary file '%s'",
 563                         nonrelative_template);
 564         }
 565         return fd;
 566 }
 567
 568 static int warn_if_unremovable(const char *op, const char *file, int rc)
 569 {
 570         int err;
 571         if (!rc || errno == ENOENT)
 572                 return 0;
 573         err = errno;
 574         warning("unable to %s %s: %s", op, file, strerror(errno));
 575         errno = err;
 576         return rc;
 577 }
 578
 579 int unlink_or_msg(const char *file, struct strbuf *err)
 580 {
 581         int rc = unlink(file);
 582
 583         assert(err);
 584
 585         if (!rc || errno == ENOENT)
 586                 return 0;
 587
 588         strbuf_addf(err, "unable to unlink %s: %s",
 589                     file, strerror(errno));
 590         return -1;
 591 }
 592
 593 int unlink_or_warn(const char *file)
 594 {
 595         return warn_if_unremovable("unlink", file, unlink(file));
 596 }
 597
 598 int rmdir_or_warn(const char *file)
 599 {
 600         return warn_if_unremovable("rmdir", file, rmdir(file));
 601 }
 602
 603 int remove_or_warn(unsigned int mode, const char *file)
 604 {
 605         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 606 }
 607
 608 void warn_on_inaccessible(const char *path)
 609 {
 610         warning(_("unable to access '%s': %s"), path, strerror(errno));
 611 }
 612
 613 static int access_error_is_ok(int err, unsigned flag)
 614 {
 615         return err == ENOENT || err == ENOTDIR ||
 616                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 617 }
 618
 619 int access_or_warn(const char *path, int mode, unsigned flag)
 620 {
 621         int ret = access(path, mode);
 622         if (ret && !access_error_is_ok(errno, flag))
 623                 warn_on_inaccessible(path);
 624         return ret;
 625 }
 626
 627 int access_or_die(const char *path, int mode, unsigned flag)
 628 {
 629         int ret = access(path, mode);
 630         if (ret && !access_error_is_ok(errno, flag))
 631                 die_errno(_("unable to access '%s'"), path);
 632         return ret;
 633 }
 634
 635 struct passwd *xgetpwuid_self(void)
 636 {
 637         struct passwd *pw;
 638
 639         errno = 0;
 640         pw = getpwuid(getuid());
 641         if (!pw)
 642                 die(_("unable to look up current user in the passwd file: %s"),
 643                     errno ? strerror(errno) : _("no such user"));
 644         return pw;
 645 }
 646
 647 char *xgetcwd(void)
 648 {
 649         struct strbuf sb = STRBUF_INIT;
 650         if (strbuf_getcwd(&sb))
 651                 die_errno(_("unable to get current working directory"));
 652         return strbuf_detach(&sb, NULL);
 653 }
 654
 655 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
 656 {
 657         va_list ap;
 658         int len;
 659
 660         va_start(ap, fmt);
 661         len = vsnprintf(dst, max, fmt, ap);
 662         va_end(ap);
 663
 664         if (len < 0)
 665                 die("BUG: your snprintf is broken");
 666         if (len >= max)
 667                 die("BUG: attempt to snprintf into too-small buffer");
 668         return len;
 669 }
 670
 671 static int write_file_v(const char *path, int fatal,
 672                         const char *fmt, va_list params)
 673 {
 674         struct strbuf sb = STRBUF_INIT;
 675         int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666);
 676         if (fd < 0) {
 677                 if (fatal)
 678                         die_errno(_("could not open %s for writing"), path);
 679                 return -1;
 680         }
 681         strbuf_vaddf(&sb, fmt, params);
 682         strbuf_complete_line(&sb);
 683         if (write_in_full(fd, sb.buf, sb.len) != sb.len) {
 684                 int err = errno;
 685                 close(fd);
 686                 strbuf_release(&sb);
 687                 errno = err;
 688                 if (fatal)
 689                         die_errno(_("could not write to %s"), path);
 690                 return -1;
 691         }
 692         strbuf_release(&sb);
 693         if (close(fd)) {
 694                 if (fatal)
 695                         die_errno(_("could not close %s"), path);
 696                 return -1;
 697         }
 698         return 0;
 699 }
 700
 701 int write_file(const char *path, const char *fmt, ...)
 702 {
 703         int status;
 704         va_list params;
 705
 706         va_start(params, fmt);
 707         status = write_file_v(path, 1, fmt, params);
 708         va_end(params);
 709         return status;
 710 }
 711
 712 int write_file_gently(const char *path, const char *fmt, ...)
 713 {
 714         int status;
 715         va_list params;
 716
 717         va_start(params, fmt);
 718         status = write_file_v(path, 0, fmt, params);
 719         va_end(params);
 720         return status;
 721 }
 722
 723 void sleep_millisec(int millisec)
 724 {
 725         poll(NULL, 0, millisec);
 726 }