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         if (unsigned_mult_overflows(nmemb, size))
 156                 die("data too large to fit into virtual memory space");
 157
 158         memory_limit_check(size * nmemb, 0);
 159         ret = calloc(nmemb, size);
 160         if (!ret && (!nmemb || !size))
 161                 ret = calloc(1, 1);
 162         if (!ret) {
 163                 try_to_free_routine(nmemb * size);
 164                 ret = calloc(nmemb, size);
 165                 if (!ret && (!nmemb || !size))
 166                         ret = calloc(1, 1);
 167                 if (!ret)
 168                         die("Out of memory, calloc failed");
 169         }
 170         return ret;
 171 }
 172
 173 /*
 174  * Limit size of IO chunks, because huge chunks only cause pain.  OS X
 175  * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
 176  * the absence of bugs, large chunks can result in bad latencies when
 177  * you decide to kill the process.
 178  *
 179  * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
 180  * that is smaller than that, clip it to SSIZE_MAX, as a call to
 181  * read(2) or write(2) larger than that is allowed to fail.  As the last
 182  * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
 183  * to override this, if the definition of SSIZE_MAX given by the platform
 184  * is broken.
 185  */
 186 #ifndef MAX_IO_SIZE
 187 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
 188 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
 189 #  define MAX_IO_SIZE SSIZE_MAX
 190 # else
 191 #  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
 192 # endif
 193 #endif
 194
 195 /**
 196  * xopen() is the same as open(), but it die()s if the open() fails.
 197  */
 198 int xopen(const char *path, int oflag, ...)
 199 {
 200         mode_t mode = 0;
 201         va_list ap;
 202
 203         /*
 204          * va_arg() will have undefined behavior if the specified type is not
 205          * compatible with the argument type. Since integers are promoted to
 206          * ints, we fetch the next argument as an int, and then cast it to a
 207          * mode_t to avoid undefined behavior.
 208          */
 209         va_start(ap, oflag);
 210         if (oflag & O_CREAT)
 211                 mode = va_arg(ap, int);
 212         va_end(ap);
 213
 214         for (;;) {
 215                 int fd = open(path, oflag, mode);
 216                 if (fd >= 0)
 217                         return fd;
 218                 if (errno == EINTR)
 219                         continue;
 220
 221                 if ((oflag & O_RDWR) == O_RDWR)
 222                         die_errno(_("could not open '%s' for reading and writing"), path);
 223                 else if ((oflag & O_WRONLY) == O_WRONLY)
 224                         die_errno(_("could not open '%s' for writing"), path);
 225                 else
 226                         die_errno(_("could not open '%s' for reading"), path);
 227         }
 228 }
 229
 230 /*
 231  * xread() is the same a read(), but it automatically restarts read()
 232  * operations with a recoverable error (EAGAIN and EINTR). xread()
 233  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 234  */
 235 ssize_t xread(int fd, void *buf, size_t len)
 236 {
 237         ssize_t nr;
 238         if (len > MAX_IO_SIZE)
 239             len = MAX_IO_SIZE;
 240         while (1) {
 241                 nr = read(fd, buf, len);
 242                 if (nr < 0) {
 243                         if (errno == EINTR)
 244                                 continue;
 245                         if (errno == EAGAIN || errno == EWOULDBLOCK) {
 246                                 struct pollfd pfd;
 247                                 pfd.events = POLLIN;
 248                                 pfd.fd = fd;
 249                                 /*
 250                                  * it is OK if this poll() failed; we
 251                                  * want to leave this infinite loop
 252                                  * only when read() returns with
 253                                  * success, or an expected failure,
 254                                  * which would be checked by the next
 255                                  * call to read(2).
 256                                  */
 257                                 poll(&pfd, 1, -1);
 258                         }
 259                 }
 260                 return nr;
 261         }
 262 }
 263
 264 /*
 265  * xwrite() is the same a write(), but it automatically restarts write()
 266  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 267  * GUARANTEE that "len" bytes is written even if the operation is successful.
 268  */
 269 ssize_t xwrite(int fd, const void *buf, size_t len)
 270 {
 271         ssize_t nr;
 272         if (len > MAX_IO_SIZE)
 273             len = MAX_IO_SIZE;
 274         while (1) {
 275                 nr = write(fd, buf, len);
 276                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 277                         continue;
 278                 return nr;
 279         }
 280 }
 281
 282 /*
 283  * xpread() is the same as pread(), but it automatically restarts pread()
 284  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 285  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 286  */
 287 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 288 {
 289         ssize_t nr;
 290         if (len > MAX_IO_SIZE)
 291                 len = MAX_IO_SIZE;
 292         while (1) {
 293                 nr = pread(fd, buf, len, offset);
 294                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 295                         continue;
 296                 return nr;
 297         }
 298 }
 299
 300 ssize_t read_in_full(int fd, void *buf, size_t count)
 301 {
 302         char *p = buf;
 303         ssize_t total = 0;
 304
 305         while (count > 0) {
 306                 ssize_t loaded = xread(fd, p, count);
 307                 if (loaded < 0)
 308                         return -1;
 309                 if (loaded == 0)
 310                         return total;
 311                 count -= loaded;
 312                 p += loaded;
 313                 total += loaded;
 314         }
 315
 316         return total;
 317 }
 318
 319 ssize_t write_in_full(int fd, const void *buf, size_t count)
 320 {
 321         const char *p = buf;
 322         ssize_t total = 0;
 323
 324         while (count > 0) {
 325                 ssize_t written = xwrite(fd, p, count);
 326                 if (written < 0)
 327                         return -1;
 328                 if (!written) {
 329                         errno = ENOSPC;
 330                         return -1;
 331                 }
 332                 count -= written;
 333                 p += written;
 334                 total += written;
 335         }
 336
 337         return total;
 338 }
 339
 340 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 341 {
 342         char *p = buf;
 343         ssize_t total = 0;
 344
 345         while (count > 0) {
 346                 ssize_t loaded = xpread(fd, p, count, offset);
 347                 if (loaded < 0)
 348                         return -1;
 349                 if (loaded == 0)
 350                         return total;
 351                 count -= loaded;
 352                 p += loaded;
 353                 total += loaded;
 354                 offset += loaded;
 355         }
 356
 357         return total;
 358 }
 359
 360 int xdup(int fd)
 361 {
 362         int ret = dup(fd);
 363         if (ret < 0)
 364                 die_errno("dup failed");
 365         return ret;
 366 }
 367
 368 /**
 369  * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
 370  */
 371 FILE *xfopen(const char *path, const char *mode)
 372 {
 373         for (;;) {
 374                 FILE *fp = fopen(path, mode);
 375                 if (fp)
 376                         return fp;
 377                 if (errno == EINTR)
 378                         continue;
 379
 380                 if (*mode && mode[1] == '+')
 381                         die_errno(_("could not open '%s' for reading and writing"), path);
 382                 else if (*mode == 'w' || *mode == 'a')
 383                         die_errno(_("could not open '%s' for writing"), path);
 384                 else
 385                         die_errno(_("could not open '%s' for reading"), path);
 386         }
 387 }
 388
 389 FILE *xfdopen(int fd, const char *mode)
 390 {
 391         FILE *stream = fdopen(fd, mode);
 392         if (stream == NULL)
 393                 die_errno("Out of memory? fdopen failed");
 394         return stream;
 395 }
 396
 397 FILE *fopen_for_writing(const char *path)
 398 {
 399         FILE *ret = fopen(path, "w");
 400
 401         if (!ret && errno == EPERM) {
 402                 if (!unlink(path))
 403                         ret = fopen(path, "w");
 404                 else
 405                         errno = EPERM;
 406         }
 407         return ret;
 408 }
 409
 410 int xmkstemp(char *template)
 411 {
 412         int fd;
 413         char origtemplate[PATH_MAX];
 414         strlcpy(origtemplate, template, sizeof(origtemplate));
 415
 416         fd = mkstemp(template);
 417         if (fd < 0) {
 418                 int saved_errno = errno;
 419                 const char *nonrelative_template;
 420
 421                 if (strlen(template) != strlen(origtemplate))
 422                         template = origtemplate;
 423
 424                 nonrelative_template = absolute_path(template);
 425                 errno = saved_errno;
 426                 die_errno("Unable to create temporary file '%s'",
 427                         nonrelative_template);
 428         }
 429         return fd;
 430 }
 431
 432 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 433 int git_mkstemp(char *path, size_t len, const char *template)
 434 {
 435         const char *tmp;
 436         size_t n;
 437
 438         tmp = getenv("TMPDIR");
 439         if (!tmp)
 440                 tmp = "/tmp";
 441         n = snprintf(path, len, "%s/%s", tmp, template);
 442         if (len <= n) {
 443                 errno = ENAMETOOLONG;
 444                 return -1;
 445         }
 446         return mkstemp(path);
 447 }
 448
 449 /* Adapted from libiberty's mkstemp.c. */
 450
 451 #undef TMP_MAX
 452 #define TMP_MAX 16384
 453
 454 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 455 {
 456         static const char letters[] =
 457                 "abcdefghijklmnopqrstuvwxyz"
 458                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 459                 "0123456789";
 460         static const int num_letters = 62;
 461         uint64_t value;
 462         struct timeval tv;
 463         char *template;
 464         size_t len;
 465         int fd, count;
 466
 467         len = strlen(pattern);
 468
 469         if (len < 6 + suffix_len) {
 470                 errno = EINVAL;
 471                 return -1;
 472         }
 473
 474         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 475                 errno = EINVAL;
 476                 return -1;
 477         }
 478
 479         /*
 480          * Replace pattern's XXXXXX characters with randomness.
 481          * Try TMP_MAX different filenames.
 482          */
 483         gettimeofday(&tv, NULL);
 484         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 485         template = &pattern[len - 6 - suffix_len];
 486         for (count = 0; count < TMP_MAX; ++count) {
 487                 uint64_t v = value;
 488                 /* Fill in the random bits. */
 489                 template[0] = letters[v % num_letters]; v /= num_letters;
 490                 template[1] = letters[v % num_letters]; v /= num_letters;
 491                 template[2] = letters[v % num_letters]; v /= num_letters;
 492                 template[3] = letters[v % num_letters]; v /= num_letters;
 493                 template[4] = letters[v % num_letters]; v /= num_letters;
 494                 template[5] = letters[v % num_letters]; v /= num_letters;
 495
 496                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 497                 if (fd >= 0)
 498                         return fd;
 499                 /*
 500                  * Fatal error (EPERM, ENOSPC etc).
 501                  * It doesn't make sense to loop.
 502                  */
 503                 if (errno != EEXIST)
 504                         break;
 505                 /*
 506                  * This is a random value.  It is only necessary that
 507                  * the next TMP_MAX values generated by adding 7777 to
 508                  * VALUE are different with (module 2^32).
 509                  */
 510                 value += 7777;
 511         }
 512         /* We return the null string if we can't find a unique file name.  */
 513         pattern[0] = '\0';
 514         return -1;
 515 }
 516
 517 int git_mkstemp_mode(char *pattern, int mode)
 518 {
 519         /* mkstemp is just mkstemps with no suffix */
 520         return git_mkstemps_mode(pattern, 0, mode);
 521 }
 522
 523 #ifdef NO_MKSTEMPS
 524 int gitmkstemps(char *pattern, int suffix_len)
 525 {
 526         return git_mkstemps_mode(pattern, suffix_len, 0600);
 527 }
 528 #endif
 529
 530 int xmkstemp_mode(char *template, int mode)
 531 {
 532         int fd;
 533         char origtemplate[PATH_MAX];
 534         strlcpy(origtemplate, template, sizeof(origtemplate));
 535
 536         fd = git_mkstemp_mode(template, mode);
 537         if (fd < 0) {
 538                 int saved_errno = errno;
 539                 const char *nonrelative_template;
 540
 541                 if (!template[0])
 542                         template = origtemplate;
 543
 544                 nonrelative_template = absolute_path(template);
 545                 errno = saved_errno;
 546                 die_errno("Unable to create temporary file '%s'",
 547                         nonrelative_template);
 548         }
 549         return fd;
 550 }
 551
 552 static int warn_if_unremovable(const char *op, const char *file, int rc)
 553 {
 554         int err;
 555         if (!rc || errno == ENOENT)
 556                 return 0;
 557         err = errno;
 558         warning("unable to %s %s: %s", op, file, strerror(errno));
 559         errno = err;
 560         return rc;
 561 }
 562
 563 int unlink_or_msg(const char *file, struct strbuf *err)
 564 {
 565         int rc = unlink(file);
 566
 567         assert(err);
 568
 569         if (!rc || errno == ENOENT)
 570                 return 0;
 571
 572         strbuf_addf(err, "unable to unlink %s: %s",
 573                     file, strerror(errno));
 574         return -1;
 575 }
 576
 577 int unlink_or_warn(const char *file)
 578 {
 579         return warn_if_unremovable("unlink", file, unlink(file));
 580 }
 581
 582 int rmdir_or_warn(const char *file)
 583 {
 584         return warn_if_unremovable("rmdir", file, rmdir(file));
 585 }
 586
 587 int remove_or_warn(unsigned int mode, const char *file)
 588 {
 589         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 590 }
 591
 592 void warn_on_inaccessible(const char *path)
 593 {
 594         warning(_("unable to access '%s': %s"), path, strerror(errno));
 595 }
 596
 597 static int access_error_is_ok(int err, unsigned flag)
 598 {
 599         return err == ENOENT || err == ENOTDIR ||
 600                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 601 }
 602
 603 int access_or_warn(const char *path, int mode, unsigned flag)
 604 {
 605         int ret = access(path, mode);
 606         if (ret && !access_error_is_ok(errno, flag))
 607                 warn_on_inaccessible(path);
 608         return ret;
 609 }
 610
 611 int access_or_die(const char *path, int mode, unsigned flag)
 612 {
 613         int ret = access(path, mode);
 614         if (ret && !access_error_is_ok(errno, flag))
 615                 die_errno(_("unable to access '%s'"), path);
 616         return ret;
 617 }
 618
 619 char *xgetcwd(void)
 620 {
 621         struct strbuf sb = STRBUF_INIT;
 622         if (strbuf_getcwd(&sb))
 623                 die_errno(_("unable to get current working directory"));
 624         return strbuf_detach(&sb, NULL);
 625 }
 626
 627 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
 628 {
 629         va_list ap;
 630         int len;
 631
 632         va_start(ap, fmt);
 633         len = vsnprintf(dst, max, fmt, ap);
 634         va_end(ap);
 635
 636         if (len < 0)
 637                 die("BUG: your snprintf is broken");
 638         if (len >= max)
 639                 die("BUG: attempt to snprintf into too-small buffer");
 640         return len;
 641 }
 642
 643 static int write_file_v(const char *path, int fatal,
 644                         const char *fmt, va_list params)
 645 {
 646         struct strbuf sb = STRBUF_INIT;
 647         int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666);
 648         if (fd < 0) {
 649                 if (fatal)
 650                         die_errno(_("could not open %s for writing"), path);
 651                 return -1;
 652         }
 653         strbuf_vaddf(&sb, fmt, params);
 654         strbuf_complete_line(&sb);
 655         if (write_in_full(fd, sb.buf, sb.len) != sb.len) {
 656                 int err = errno;
 657                 close(fd);
 658                 strbuf_release(&sb);
 659                 errno = err;
 660                 if (fatal)
 661                         die_errno(_("could not write to %s"), path);
 662                 return -1;
 663         }
 664         strbuf_release(&sb);
 665         if (close(fd)) {
 666                 if (fatal)
 667                         die_errno(_("could not close %s"), path);
 668                 return -1;
 669         }
 670         return 0;
 671 }
 672
 673 int write_file(const char *path, const char *fmt, ...)
 674 {
 675         int status;
 676         va_list params;
 677
 678         va_start(params, fmt);
 679         status = write_file_v(path, 1, fmt, params);
 680         va_end(params);
 681         return status;
 682 }
 683
 684 int write_file_gently(const char *path, const char *fmt, ...)
 685 {
 686         int status;
 687         va_list params;
 688
 689         va_start(params, fmt);
 690         status = write_file_v(path, 0, fmt, params);
 691         va_end(params);
 692         return status;
 693 }
 694
 695 void sleep_millisec(int millisec)
 696 {
 697         poll(NULL, 0, millisec);
 698 }