wrapper.c

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