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) && (errno == EAGAIN || errno == EINTR))
 243                         continue;
 244                 return nr;
 245         }
 246 }
 247
 248 /*
 249  * xwrite() is the same a write(), but it automatically restarts write()
 250  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 251  * GUARANTEE that "len" bytes is written even if the operation is successful.
 252  */
 253 ssize_t xwrite(int fd, const void *buf, size_t len)
 254 {
 255         ssize_t nr;
 256         if (len > MAX_IO_SIZE)
 257             len = MAX_IO_SIZE;
 258         while (1) {
 259                 nr = write(fd, buf, len);
 260                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 261                         continue;
 262                 return nr;
 263         }
 264 }
 265
 266 /*
 267  * xpread() is the same as pread(), but it automatically restarts pread()
 268  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 269  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 270  */
 271 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 272 {
 273         ssize_t nr;
 274         if (len > MAX_IO_SIZE)
 275                 len = MAX_IO_SIZE;
 276         while (1) {
 277                 nr = pread(fd, buf, len, offset);
 278                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 279                         continue;
 280                 return nr;
 281         }
 282 }
 283
 284 ssize_t read_in_full(int fd, void *buf, size_t count)
 285 {
 286         char *p = buf;
 287         ssize_t total = 0;
 288
 289         while (count > 0) {
 290                 ssize_t loaded = xread(fd, p, count);
 291                 if (loaded < 0)
 292                         return -1;
 293                 if (loaded == 0)
 294                         return total;
 295                 count -= loaded;
 296                 p += loaded;
 297                 total += loaded;
 298         }
 299
 300         return total;
 301 }
 302
 303 ssize_t write_in_full(int fd, const void *buf, size_t count)
 304 {
 305         const char *p = buf;
 306         ssize_t total = 0;
 307
 308         while (count > 0) {
 309                 ssize_t written = xwrite(fd, p, count);
 310                 if (written < 0)
 311                         return -1;
 312                 if (!written) {
 313                         errno = ENOSPC;
 314                         return -1;
 315                 }
 316                 count -= written;
 317                 p += written;
 318                 total += written;
 319         }
 320
 321         return total;
 322 }
 323
 324 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 325 {
 326         char *p = buf;
 327         ssize_t total = 0;
 328
 329         while (count > 0) {
 330                 ssize_t loaded = xpread(fd, p, count, offset);
 331                 if (loaded < 0)
 332                         return -1;
 333                 if (loaded == 0)
 334                         return total;
 335                 count -= loaded;
 336                 p += loaded;
 337                 total += loaded;
 338                 offset += loaded;
 339         }
 340
 341         return total;
 342 }
 343
 344 int xdup(int fd)
 345 {
 346         int ret = dup(fd);
 347         if (ret < 0)
 348                 die_errno("dup failed");
 349         return ret;
 350 }
 351
 352 /**
 353  * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
 354  */
 355 FILE *xfopen(const char *path, const char *mode)
 356 {
 357         for (;;) {
 358                 FILE *fp = fopen(path, mode);
 359                 if (fp)
 360                         return fp;
 361                 if (errno == EINTR)
 362                         continue;
 363
 364                 if (*mode && mode[1] == '+')
 365                         die_errno(_("could not open '%s' for reading and writing"), path);
 366                 else if (*mode == 'w' || *mode == 'a')
 367                         die_errno(_("could not open '%s' for writing"), path);
 368                 else
 369                         die_errno(_("could not open '%s' for reading"), path);
 370         }
 371 }
 372
 373 FILE *xfdopen(int fd, const char *mode)
 374 {
 375         FILE *stream = fdopen(fd, mode);
 376         if (stream == NULL)
 377                 die_errno("Out of memory? fdopen failed");
 378         return stream;
 379 }
 380
 381 FILE *fopen_for_writing(const char *path)
 382 {
 383         FILE *ret = fopen(path, "w");
 384
 385         if (!ret && errno == EPERM) {
 386                 if (!unlink(path))
 387                         ret = fopen(path, "w");
 388                 else
 389                         errno = EPERM;
 390         }
 391         return ret;
 392 }
 393
 394 int xmkstemp(char *template)
 395 {
 396         int fd;
 397         char origtemplate[PATH_MAX];
 398         strlcpy(origtemplate, template, sizeof(origtemplate));
 399
 400         fd = mkstemp(template);
 401         if (fd < 0) {
 402                 int saved_errno = errno;
 403                 const char *nonrelative_template;
 404
 405                 if (strlen(template) != strlen(origtemplate))
 406                         template = origtemplate;
 407
 408                 nonrelative_template = absolute_path(template);
 409                 errno = saved_errno;
 410                 die_errno("Unable to create temporary file '%s'",
 411                         nonrelative_template);
 412         }
 413         return fd;
 414 }
 415
 416 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 417 int git_mkstemp(char *path, size_t len, const char *template)
 418 {
 419         const char *tmp;
 420         size_t n;
 421
 422         tmp = getenv("TMPDIR");
 423         if (!tmp)
 424                 tmp = "/tmp";
 425         n = snprintf(path, len, "%s/%s", tmp, template);
 426         if (len <= n) {
 427                 errno = ENAMETOOLONG;
 428                 return -1;
 429         }
 430         return mkstemp(path);
 431 }
 432
 433 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 434 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 435 {
 436         const char *tmp;
 437         size_t n;
 438
 439         tmp = getenv("TMPDIR");
 440         if (!tmp)
 441                 tmp = "/tmp";
 442         n = snprintf(path, len, "%s/%s", tmp, template);
 443         if (len <= n) {
 444                 errno = ENAMETOOLONG;
 445                 return -1;
 446         }
 447         return mkstemps(path, suffix_len);
 448 }
 449
 450 /* Adapted from libiberty's mkstemp.c. */
 451
 452 #undef TMP_MAX
 453 #define TMP_MAX 16384
 454
 455 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 456 {
 457         static const char letters[] =
 458                 "abcdefghijklmnopqrstuvwxyz"
 459                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 460                 "0123456789";
 461         static const int num_letters = 62;
 462         uint64_t value;
 463         struct timeval tv;
 464         char *template;
 465         size_t len;
 466         int fd, count;
 467
 468         len = strlen(pattern);
 469
 470         if (len < 6 + suffix_len) {
 471                 errno = EINVAL;
 472                 return -1;
 473         }
 474
 475         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 476                 errno = EINVAL;
 477                 return -1;
 478         }
 479
 480         /*
 481          * Replace pattern's XXXXXX characters with randomness.
 482          * Try TMP_MAX different filenames.
 483          */
 484         gettimeofday(&tv, NULL);
 485         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 486         template = &pattern[len - 6 - suffix_len];
 487         for (count = 0; count < TMP_MAX; ++count) {
 488                 uint64_t v = value;
 489                 /* Fill in the random bits. */
 490                 template[0] = letters[v % num_letters]; v /= num_letters;
 491                 template[1] = letters[v % num_letters]; v /= num_letters;
 492                 template[2] = letters[v % num_letters]; v /= num_letters;
 493                 template[3] = letters[v % num_letters]; v /= num_letters;
 494                 template[4] = letters[v % num_letters]; v /= num_letters;
 495                 template[5] = letters[v % num_letters]; v /= num_letters;
 496
 497                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 498                 if (fd >= 0)
 499                         return fd;
 500                 /*
 501                  * Fatal error (EPERM, ENOSPC etc).
 502                  * It doesn't make sense to loop.
 503                  */
 504                 if (errno != EEXIST)
 505                         break;
 506                 /*
 507                  * This is a random value.  It is only necessary that
 508                  * the next TMP_MAX values generated by adding 7777 to
 509                  * VALUE are different with (module 2^32).
 510                  */
 511                 value += 7777;
 512         }
 513         /* We return the null string if we can't find a unique file name.  */
 514         pattern[0] = '\0';
 515         return -1;
 516 }
 517
 518 int git_mkstemp_mode(char *pattern, int mode)
 519 {
 520         /* mkstemp is just mkstemps with no suffix */
 521         return git_mkstemps_mode(pattern, 0, mode);
 522 }
 523
 524 #ifdef NO_MKSTEMPS
 525 int gitmkstemps(char *pattern, int suffix_len)
 526 {
 527         return git_mkstemps_mode(pattern, suffix_len, 0600);
 528 }
 529 #endif
 530
 531 int xmkstemp_mode(char *template, int mode)
 532 {
 533         int fd;
 534         char origtemplate[PATH_MAX];
 535         strlcpy(origtemplate, template, sizeof(origtemplate));
 536
 537         fd = git_mkstemp_mode(template, mode);
 538         if (fd < 0) {
 539                 int saved_errno = errno;
 540                 const char *nonrelative_template;
 541
 542                 if (!template[0])
 543                         template = origtemplate;
 544
 545                 nonrelative_template = absolute_path(template);
 546                 errno = saved_errno;
 547                 die_errno("Unable to create temporary file '%s'",
 548                         nonrelative_template);
 549         }
 550         return fd;
 551 }
 552
 553 static int warn_if_unremovable(const char *op, const char *file, int rc)
 554 {
 555         int err;
 556         if (!rc || errno == ENOENT)
 557                 return 0;
 558         err = errno;
 559         warning("unable to %s %s: %s", op, file, strerror(errno));
 560         errno = err;
 561         return rc;
 562 }
 563
 564 int unlink_or_msg(const char *file, struct strbuf *err)
 565 {
 566         int rc = unlink(file);
 567
 568         assert(err);
 569
 570         if (!rc || errno == ENOENT)
 571                 return 0;
 572
 573         strbuf_addf(err, "unable to unlink %s: %s",
 574                     file, strerror(errno));
 575         return -1;
 576 }
 577
 578 int unlink_or_warn(const char *file)
 579 {
 580         return warn_if_unremovable("unlink", file, unlink(file));
 581 }
 582
 583 int rmdir_or_warn(const char *file)
 584 {
 585         return warn_if_unremovable("rmdir", file, rmdir(file));
 586 }
 587
 588 int remove_or_warn(unsigned int mode, const char *file)
 589 {
 590         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 591 }
 592
 593 void warn_on_inaccessible(const char *path)
 594 {
 595         warning(_("unable to access '%s': %s"), path, strerror(errno));
 596 }
 597
 598 static int access_error_is_ok(int err, unsigned flag)
 599 {
 600         return err == ENOENT || err == ENOTDIR ||
 601                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 602 }
 603
 604 int access_or_warn(const char *path, int mode, unsigned flag)
 605 {
 606         int ret = access(path, mode);
 607         if (ret && !access_error_is_ok(errno, flag))
 608                 warn_on_inaccessible(path);
 609         return ret;
 610 }
 611
 612 int access_or_die(const char *path, int mode, unsigned flag)
 613 {
 614         int ret = access(path, mode);
 615         if (ret && !access_error_is_ok(errno, flag))
 616                 die_errno(_("unable to access '%s'"), path);
 617         return ret;
 618 }
 619
 620 char *xgetcwd(void)
 621 {
 622         struct strbuf sb = STRBUF_INIT;
 623         if (strbuf_getcwd(&sb))
 624                 die_errno(_("unable to get current working directory"));
 625         return strbuf_detach(&sb, NULL);
 626 }
 627
 628 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
 629 {
 630         va_list ap;
 631         int len;
 632
 633         va_start(ap, fmt);
 634         len = vsnprintf(dst, max, fmt, ap);
 635         va_end(ap);
 636
 637         if (len < 0)
 638                 die("BUG: your snprintf is broken");
 639         if (len >= max)
 640                 die("BUG: attempt to snprintf into too-small buffer");
 641         return len;
 642 }
 643
 644 static int write_file_v(const char *path, int fatal,
 645                         const char *fmt, va_list params)
 646 {
 647         struct strbuf sb = STRBUF_INIT;
 648         int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666);
 649         if (fd < 0) {
 650                 if (fatal)
 651                         die_errno(_("could not open %s for writing"), path);
 652                 return -1;
 653         }
 654         strbuf_vaddf(&sb, fmt, params);
 655         strbuf_complete_line(&sb);
 656         if (write_in_full(fd, sb.buf, sb.len) != sb.len) {
 657                 int err = errno;
 658                 close(fd);
 659                 strbuf_release(&sb);
 660                 errno = err;
 661                 if (fatal)
 662                         die_errno(_("could not write to %s"), path);
 663                 return -1;
 664         }
 665         strbuf_release(&sb);
 666         if (close(fd)) {
 667                 if (fatal)
 668                         die_errno(_("could not close %s"), path);
 669                 return -1;
 670         }
 671         return 0;
 672 }
 673
 674 int write_file(const char *path, const char *fmt, ...)
 675 {
 676         int status;
 677         va_list params;
 678
 679         va_start(params, fmt);
 680         status = write_file_v(path, 1, fmt, params);
 681         va_end(params);
 682         return status;
 683 }
 684
 685 int write_file_gently(const char *path, const char *fmt, ...)
 686 {
 687         int status;
 688         va_list params;
 689
 690         va_start(params, fmt);
 691         status = write_file_v(path, 0, fmt, params);
 692         va_end(params);
 693         return status;
 694 }
 695
 696 void sleep_millisec(int millisec)
 697 {
 698         poll(NULL, 0, millisec);
 699 }