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                                 /*
 247                                  * it is OK if this poll() failed; we
 248                                  * want to leave this infinite loop
 249                                  * only when read() returns with
 250                                  * success, or an expected failure,
 251                                  * which would be checked by the next
 252                                  * call to read(2).
 253                                  */
 254                                 poll(&pfd, 1, -1);
 255                         }
 256                 }
 257                 return nr;
 258         }
 259 }
 260
 261 /*
 262  * xwrite() is the same a write(), but it automatically restarts write()
 263  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 264  * GUARANTEE that "len" bytes is written even if the operation is successful.
 265  */
 266 ssize_t xwrite(int fd, const void *buf, size_t len)
 267 {
 268         ssize_t nr;
 269         if (len > MAX_IO_SIZE)
 270             len = MAX_IO_SIZE;
 271         while (1) {
 272                 nr = write(fd, buf, len);
 273                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 274                         continue;
 275                 return nr;
 276         }
 277 }
 278
 279 /*
 280  * xpread() is the same as pread(), but it automatically restarts pread()
 281  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 282  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 283  */
 284 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 285 {
 286         ssize_t nr;
 287         if (len > MAX_IO_SIZE)
 288                 len = MAX_IO_SIZE;
 289         while (1) {
 290                 nr = pread(fd, buf, len, offset);
 291                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 292                         continue;
 293                 return nr;
 294         }
 295 }
 296
 297 ssize_t read_in_full(int fd, void *buf, size_t count)
 298 {
 299         char *p = buf;
 300         ssize_t total = 0;
 301
 302         while (count > 0) {
 303                 ssize_t loaded = xread(fd, p, count);
 304                 if (loaded < 0)
 305                         return -1;
 306                 if (loaded == 0)
 307                         return total;
 308                 count -= loaded;
 309                 p += loaded;
 310                 total += loaded;
 311         }
 312
 313         return total;
 314 }
 315
 316 ssize_t write_in_full(int fd, const void *buf, size_t count)
 317 {
 318         const char *p = buf;
 319         ssize_t total = 0;
 320
 321         while (count > 0) {
 322                 ssize_t written = xwrite(fd, p, count);
 323                 if (written < 0)
 324                         return -1;
 325                 if (!written) {
 326                         errno = ENOSPC;
 327                         return -1;
 328                 }
 329                 count -= written;
 330                 p += written;
 331                 total += written;
 332         }
 333
 334         return total;
 335 }
 336
 337 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 338 {
 339         char *p = buf;
 340         ssize_t total = 0;
 341
 342         while (count > 0) {
 343                 ssize_t loaded = xpread(fd, p, count, offset);
 344                 if (loaded < 0)
 345                         return -1;
 346                 if (loaded == 0)
 347                         return total;
 348                 count -= loaded;
 349                 p += loaded;
 350                 total += loaded;
 351                 offset += loaded;
 352         }
 353
 354         return total;
 355 }
 356
 357 int xdup(int fd)
 358 {
 359         int ret = dup(fd);
 360         if (ret < 0)
 361                 die_errno("dup failed");
 362         return ret;
 363 }
 364
 365 /**
 366  * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
 367  */
 368 FILE *xfopen(const char *path, const char *mode)
 369 {
 370         for (;;) {
 371                 FILE *fp = fopen(path, mode);
 372                 if (fp)
 373                         return fp;
 374                 if (errno == EINTR)
 375                         continue;
 376
 377                 if (*mode && mode[1] == '+')
 378                         die_errno(_("could not open '%s' for reading and writing"), path);
 379                 else if (*mode == 'w' || *mode == 'a')
 380                         die_errno(_("could not open '%s' for writing"), path);
 381                 else
 382                         die_errno(_("could not open '%s' for reading"), path);
 383         }
 384 }
 385
 386 FILE *xfdopen(int fd, const char *mode)
 387 {
 388         FILE *stream = fdopen(fd, mode);
 389         if (stream == NULL)
 390                 die_errno("Out of memory? fdopen failed");
 391         return stream;
 392 }
 393
 394 FILE *fopen_for_writing(const char *path)
 395 {
 396         FILE *ret = fopen(path, "w");
 397
 398         if (!ret && errno == EPERM) {
 399                 if (!unlink(path))
 400                         ret = fopen(path, "w");
 401                 else
 402                         errno = EPERM;
 403         }
 404         return ret;
 405 }
 406
 407 int xmkstemp(char *template)
 408 {
 409         int fd;
 410         char origtemplate[PATH_MAX];
 411         strlcpy(origtemplate, template, sizeof(origtemplate));
 412
 413         fd = mkstemp(template);
 414         if (fd < 0) {
 415                 int saved_errno = errno;
 416                 const char *nonrelative_template;
 417
 418                 if (strlen(template) != strlen(origtemplate))
 419                         template = origtemplate;
 420
 421                 nonrelative_template = absolute_path(template);
 422                 errno = saved_errno;
 423                 die_errno("Unable to create temporary file '%s'",
 424                         nonrelative_template);
 425         }
 426         return fd;
 427 }
 428
 429 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 430 int git_mkstemp(char *path, size_t len, const char *template)
 431 {
 432         const char *tmp;
 433         size_t n;
 434
 435         tmp = getenv("TMPDIR");
 436         if (!tmp)
 437                 tmp = "/tmp";
 438         n = snprintf(path, len, "%s/%s", tmp, template);
 439         if (len <= n) {
 440                 errno = ENAMETOOLONG;
 441                 return -1;
 442         }
 443         return mkstemp(path);
 444 }
 445
 446 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 447 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 448 {
 449         const char *tmp;
 450         size_t n;
 451
 452         tmp = getenv("TMPDIR");
 453         if (!tmp)
 454                 tmp = "/tmp";
 455         n = snprintf(path, len, "%s/%s", tmp, template);
 456         if (len <= n) {
 457                 errno = ENAMETOOLONG;
 458                 return -1;
 459         }
 460         return mkstemps(path, suffix_len);
 461 }
 462
 463 /* Adapted from libiberty's mkstemp.c. */
 464
 465 #undef TMP_MAX
 466 #define TMP_MAX 16384
 467
 468 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 469 {
 470         static const char letters[] =
 471                 "abcdefghijklmnopqrstuvwxyz"
 472                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 473                 "0123456789";
 474         static const int num_letters = 62;
 475         uint64_t value;
 476         struct timeval tv;
 477         char *template;
 478         size_t len;
 479         int fd, count;
 480
 481         len = strlen(pattern);
 482
 483         if (len < 6 + suffix_len) {
 484                 errno = EINVAL;
 485                 return -1;
 486         }
 487
 488         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 489                 errno = EINVAL;
 490                 return -1;
 491         }
 492
 493         /*
 494          * Replace pattern's XXXXXX characters with randomness.
 495          * Try TMP_MAX different filenames.
 496          */
 497         gettimeofday(&tv, NULL);
 498         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 499         template = &pattern[len - 6 - suffix_len];
 500         for (count = 0; count < TMP_MAX; ++count) {
 501                 uint64_t v = value;
 502                 /* Fill in the random bits. */
 503                 template[0] = letters[v % num_letters]; v /= num_letters;
 504                 template[1] = letters[v % num_letters]; v /= num_letters;
 505                 template[2] = letters[v % num_letters]; v /= num_letters;
 506                 template[3] = letters[v % num_letters]; v /= num_letters;
 507                 template[4] = letters[v % num_letters]; v /= num_letters;
 508                 template[5] = letters[v % num_letters]; v /= num_letters;
 509
 510                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 511                 if (fd >= 0)
 512                         return fd;
 513                 /*
 514                  * Fatal error (EPERM, ENOSPC etc).
 515                  * It doesn't make sense to loop.
 516                  */
 517                 if (errno != EEXIST)
 518                         break;
 519                 /*
 520                  * This is a random value.  It is only necessary that
 521                  * the next TMP_MAX values generated by adding 7777 to
 522                  * VALUE are different with (module 2^32).
 523                  */
 524                 value += 7777;
 525         }
 526         /* We return the null string if we can't find a unique file name.  */
 527         pattern[0] = '\0';
 528         return -1;
 529 }
 530
 531 int git_mkstemp_mode(char *pattern, int mode)
 532 {
 533         /* mkstemp is just mkstemps with no suffix */
 534         return git_mkstemps_mode(pattern, 0, mode);
 535 }
 536
 537 #ifdef NO_MKSTEMPS
 538 int gitmkstemps(char *pattern, int suffix_len)
 539 {
 540         return git_mkstemps_mode(pattern, suffix_len, 0600);
 541 }
 542 #endif
 543
 544 int xmkstemp_mode(char *template, int mode)
 545 {
 546         int fd;
 547         char origtemplate[PATH_MAX];
 548         strlcpy(origtemplate, template, sizeof(origtemplate));
 549
 550         fd = git_mkstemp_mode(template, mode);
 551         if (fd < 0) {
 552                 int saved_errno = errno;
 553                 const char *nonrelative_template;
 554
 555                 if (!template[0])
 556                         template = origtemplate;
 557
 558                 nonrelative_template = absolute_path(template);
 559                 errno = saved_errno;
 560                 die_errno("Unable to create temporary file '%s'",
 561                         nonrelative_template);
 562         }
 563         return fd;
 564 }
 565
 566 static int warn_if_unremovable(const char *op, const char *file, int rc)
 567 {
 568         int err;
 569         if (!rc || errno == ENOENT)
 570                 return 0;
 571         err = errno;
 572         warning("unable to %s %s: %s", op, file, strerror(errno));
 573         errno = err;
 574         return rc;
 575 }
 576
 577 int unlink_or_msg(const char *file, struct strbuf *err)
 578 {
 579         int rc = unlink(file);
 580
 581         assert(err);
 582
 583         if (!rc || errno == ENOENT)
 584                 return 0;
 585
 586         strbuf_addf(err, "unable to unlink %s: %s",
 587                     file, strerror(errno));
 588         return -1;
 589 }
 590
 591 int unlink_or_warn(const char *file)
 592 {
 593         return warn_if_unremovable("unlink", file, unlink(file));
 594 }
 595
 596 int rmdir_or_warn(const char *file)
 597 {
 598         return warn_if_unremovable("rmdir", file, rmdir(file));
 599 }
 600
 601 int remove_or_warn(unsigned int mode, const char *file)
 602 {
 603         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 604 }
 605
 606 void warn_on_inaccessible(const char *path)
 607 {
 608         warning(_("unable to access '%s': %s"), path, strerror(errno));
 609 }
 610
 611 static int access_error_is_ok(int err, unsigned flag)
 612 {
 613         return err == ENOENT || err == ENOTDIR ||
 614                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 615 }
 616
 617 int access_or_warn(const char *path, int mode, unsigned flag)
 618 {
 619         int ret = access(path, mode);
 620         if (ret && !access_error_is_ok(errno, flag))
 621                 warn_on_inaccessible(path);
 622         return ret;
 623 }
 624
 625 int access_or_die(const char *path, int mode, unsigned flag)
 626 {
 627         int ret = access(path, mode);
 628         if (ret && !access_error_is_ok(errno, flag))
 629                 die_errno(_("unable to access '%s'"), path);
 630         return ret;
 631 }
 632
 633 char *xgetcwd(void)
 634 {
 635         struct strbuf sb = STRBUF_INIT;
 636         if (strbuf_getcwd(&sb))
 637                 die_errno(_("unable to get current working directory"));
 638         return strbuf_detach(&sb, NULL);
 639 }
 640
 641 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
 642 {
 643         va_list ap;
 644         int len;
 645
 646         va_start(ap, fmt);
 647         len = vsnprintf(dst, max, fmt, ap);
 648         va_end(ap);
 649
 650         if (len < 0)
 651                 die("BUG: your snprintf is broken");
 652         if (len >= max)
 653                 die("BUG: attempt to snprintf into too-small buffer");
 654         return len;
 655 }
 656
 657 static int write_file_v(const char *path, int fatal,
 658                         const char *fmt, va_list params)
 659 {
 660         struct strbuf sb = STRBUF_INIT;
 661         int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666);
 662         if (fd < 0) {
 663                 if (fatal)
 664                         die_errno(_("could not open %s for writing"), path);
 665                 return -1;
 666         }
 667         strbuf_vaddf(&sb, fmt, params);
 668         strbuf_complete_line(&sb);
 669         if (write_in_full(fd, sb.buf, sb.len) != sb.len) {
 670                 int err = errno;
 671                 close(fd);
 672                 strbuf_release(&sb);
 673                 errno = err;
 674                 if (fatal)
 675                         die_errno(_("could not write to %s"), path);
 676                 return -1;
 677         }
 678         strbuf_release(&sb);
 679         if (close(fd)) {
 680                 if (fatal)
 681                         die_errno(_("could not close %s"), path);
 682                 return -1;
 683         }
 684         return 0;
 685 }
 686
 687 int write_file(const char *path, const char *fmt, ...)
 688 {
 689         int status;
 690         va_list params;
 691
 692         va_start(params, fmt);
 693         status = write_file_v(path, 1, fmt, params);
 694         va_end(params);
 695         return status;
 696 }
 697
 698 int write_file_gently(const char *path, const char *fmt, ...)
 699 {
 700         int status;
 701         va_list params;
 702
 703         va_start(params, fmt);
 704         status = write_file_v(path, 0, fmt, params);
 705         va_end(params);
 706         return status;
 707 }
 708
 709 void sleep_millisec(int millisec)
 710 {
 711         poll(NULL, 0, millisec);
 712 }