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_RDWR) == O_RDWR)
 197                         die_errno(_("could not open '%s' for reading and writing"), path);
 198                 else if ((oflag & O_WRONLY) == O_WRONLY)
 199                         die_errno(_("could not open '%s' for writing"), path);
 200                 else
 201                         die_errno(_("could not open '%s' for reading"), path);
 202         }
 203 }
 204
 205 static int handle_nonblock(int fd, short poll_events, int err)
 206 {
 207         struct pollfd pfd;
 208
 209         if (err != EAGAIN && err != EWOULDBLOCK)
 210                 return 0;
 211
 212         pfd.fd = fd;
 213         pfd.events = poll_events;
 214
 215         /*
 216          * no need to check for errors, here;
 217          * a subsequent read/write will detect unrecoverable errors
 218          */
 219         poll(&pfd, 1, -1);
 220         return 1;
 221 }
 222
 223 /*
 224  * xread() is the same a read(), but it automatically restarts read()
 225  * operations with a recoverable error (EAGAIN and EINTR). xread()
 226  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 227  */
 228 ssize_t xread(int fd, void *buf, size_t len)
 229 {
 230         ssize_t nr;
 231         if (len > MAX_IO_SIZE)
 232                 len = MAX_IO_SIZE;
 233         while (1) {
 234                 nr = read(fd, buf, len);
 235                 if (nr < 0) {
 236                         if (errno == EINTR)
 237                                 continue;
 238                         if (handle_nonblock(fd, POLLIN, errno))
 239                                 continue;
 240                 }
 241                 return nr;
 242         }
 243 }
 244
 245 /*
 246  * xwrite() is the same a write(), but it automatically restarts write()
 247  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 248  * GUARANTEE that "len" bytes is written even if the operation is successful.
 249  */
 250 ssize_t xwrite(int fd, const void *buf, size_t len)
 251 {
 252         ssize_t nr;
 253         if (len > MAX_IO_SIZE)
 254                 len = MAX_IO_SIZE;
 255         while (1) {
 256                 nr = write(fd, buf, len);
 257                 if (nr < 0) {
 258                         if (errno == EINTR)
 259                                 continue;
 260                         if (handle_nonblock(fd, POLLOUT, errno))
 261                                 continue;
 262                 }
 263
 264                 return nr;
 265         }
 266 }
 267
 268 /*
 269  * xpread() is the same as pread(), but it automatically restarts pread()
 270  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 271  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 272  */
 273 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 274 {
 275         ssize_t nr;
 276         if (len > MAX_IO_SIZE)
 277                 len = MAX_IO_SIZE;
 278         while (1) {
 279                 nr = pread(fd, buf, len, offset);
 280                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 281                         continue;
 282                 return nr;
 283         }
 284 }
 285
 286 ssize_t read_in_full(int fd, void *buf, size_t count)
 287 {
 288         char *p = buf;
 289         ssize_t total = 0;
 290
 291         while (count > 0) {
 292                 ssize_t loaded = xread(fd, p, count);
 293                 if (loaded < 0)
 294                         return -1;
 295                 if (loaded == 0)
 296                         return total;
 297                 count -= loaded;
 298                 p += loaded;
 299                 total += loaded;
 300         }
 301
 302         return total;
 303 }
 304
 305 ssize_t write_in_full(int fd, const void *buf, size_t count)
 306 {
 307         const char *p = buf;
 308         ssize_t total = 0;
 309
 310         while (count > 0) {
 311                 ssize_t written = xwrite(fd, p, count);
 312                 if (written < 0)
 313                         return -1;
 314                 if (!written) {
 315                         errno = ENOSPC;
 316                         return -1;
 317                 }
 318                 count -= written;
 319                 p += written;
 320                 total += written;
 321         }
 322
 323         return total;
 324 }
 325
 326 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 327 {
 328         char *p = buf;
 329         ssize_t total = 0;
 330
 331         while (count > 0) {
 332                 ssize_t loaded = xpread(fd, p, count, offset);
 333                 if (loaded < 0)
 334                         return -1;
 335                 if (loaded == 0)
 336                         return total;
 337                 count -= loaded;
 338                 p += loaded;
 339                 total += loaded;
 340                 offset += loaded;
 341         }
 342
 343         return total;
 344 }
 345
 346 int xdup(int fd)
 347 {
 348         int ret = dup(fd);
 349         if (ret < 0)
 350                 die_errno("dup failed");
 351         return ret;
 352 }
 353
 354 /**
 355  * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
 356  */
 357 FILE *xfopen(const char *path, const char *mode)
 358 {
 359         for (;;) {
 360                 FILE *fp = fopen(path, mode);
 361                 if (fp)
 362                         return fp;
 363                 if (errno == EINTR)
 364                         continue;
 365
 366                 if (*mode && mode[1] == '+')
 367                         die_errno(_("could not open '%s' for reading and writing"), path);
 368                 else if (*mode == 'w' || *mode == 'a')
 369                         die_errno(_("could not open '%s' for writing"), path);
 370                 else
 371                         die_errno(_("could not open '%s' for reading"), path);
 372         }
 373 }
 374
 375 FILE *xfdopen(int fd, const char *mode)
 376 {
 377         FILE *stream = fdopen(fd, mode);
 378         if (stream == NULL)
 379                 die_errno("Out of memory? fdopen failed");
 380         return stream;
 381 }
 382
 383 FILE *fopen_for_writing(const char *path)
 384 {
 385         FILE *ret = fopen(path, "w");
 386
 387         if (!ret && errno == EPERM) {
 388                 if (!unlink(path))
 389                         ret = fopen(path, "w");
 390                 else
 391                         errno = EPERM;
 392         }
 393         return ret;
 394 }
 395
 396 static void warn_on_inaccessible(const char *path)
 397 {
 398         warning_errno(_("unable to access '%s'"), path);
 399 }
 400
 401 int warn_on_fopen_errors(const char *path)
 402 {
 403         if (errno != ENOENT && errno != ENOTDIR) {
 404                 warn_on_inaccessible(path);
 405                 return -1;
 406         }
 407
 408         return 0;
 409 }
 410
 411 FILE *fopen_or_warn(const char *path, const char *mode)
 412 {
 413         FILE *fp = fopen(path, mode);
 414
 415         if (fp)
 416                 return fp;
 417
 418         warn_on_fopen_errors(path);
 419         return NULL;
 420 }
 421
 422 int xmkstemp(char *filename_template)
 423 {
 424         int fd;
 425         char origtemplate[PATH_MAX];
 426         strlcpy(origtemplate, filename_template, sizeof(origtemplate));
 427
 428         fd = mkstemp(filename_template);
 429         if (fd < 0) {
 430                 int saved_errno = errno;
 431                 const char *nonrelative_template;
 432
 433                 if (strlen(filename_template) != strlen(origtemplate))
 434                         filename_template = origtemplate;
 435
 436                 nonrelative_template = absolute_path(filename_template);
 437                 errno = saved_errno;
 438                 die_errno("Unable to create temporary file '%s'",
 439                         nonrelative_template);
 440         }
 441         return fd;
 442 }
 443
 444 /* Adapted from libiberty's mkstemp.c. */
 445
 446 #undef TMP_MAX
 447 #define TMP_MAX 16384
 448
 449 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 450 {
 451         static const char letters[] =
 452                 "abcdefghijklmnopqrstuvwxyz"
 453                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 454                 "0123456789";
 455         static const int num_letters = ARRAY_SIZE(letters) - 1;
 456         static const char x_pattern[] = "XXXXXX";
 457         static const int num_x = ARRAY_SIZE(x_pattern) - 1;
 458         uint64_t value;
 459         struct timeval tv;
 460         char *filename_template;
 461         size_t len;
 462         int fd, count;
 463
 464         len = strlen(pattern);
 465
 466         if (len < num_x + suffix_len) {
 467                 errno = EINVAL;
 468                 return -1;
 469         }
 470
 471         if (strncmp(&pattern[len - num_x - suffix_len], x_pattern, num_x)) {
 472                 errno = EINVAL;
 473                 return -1;
 474         }
 475
 476         /*
 477          * Replace pattern's XXXXXX characters with randomness.
 478          * Try TMP_MAX different filenames.
 479          */
 480         gettimeofday(&tv, NULL);
 481         value = ((uint64_t)tv.tv_usec << 16) ^ tv.tv_sec ^ getpid();
 482         filename_template = &pattern[len - num_x - suffix_len];
 483         for (count = 0; count < TMP_MAX; ++count) {
 484                 uint64_t v = value;
 485                 int i;
 486                 /* Fill in the random bits. */
 487                 for (i = 0; i < num_x; i++) {
 488                         filename_template[i] = letters[v % num_letters];
 489                         v /= num_letters;
 490                 }
 491
 492                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 493                 if (fd >= 0)
 494                         return fd;
 495                 /*
 496                  * Fatal error (EPERM, ENOSPC etc).
 497                  * It doesn't make sense to loop.
 498                  */
 499                 if (errno != EEXIST)
 500                         break;
 501                 /*
 502                  * This is a random value.  It is only necessary that
 503                  * the next TMP_MAX values generated by adding 7777 to
 504                  * VALUE are different with (module 2^32).
 505                  */
 506                 value += 7777;
 507         }
 508         /* We return the null string if we can't find a unique file name.  */
 509         pattern[0] = '\0';
 510         return -1;
 511 }
 512
 513 int git_mkstemp_mode(char *pattern, int mode)
 514 {
 515         /* mkstemp is just mkstemps with no suffix */
 516         return git_mkstemps_mode(pattern, 0, mode);
 517 }
 518
 519 int xmkstemp_mode(char *filename_template, int mode)
 520 {
 521         int fd;
 522         char origtemplate[PATH_MAX];
 523         strlcpy(origtemplate, filename_template, sizeof(origtemplate));
 524
 525         fd = git_mkstemp_mode(filename_template, mode);
 526         if (fd < 0) {
 527                 int saved_errno = errno;
 528                 const char *nonrelative_template;
 529
 530                 if (!filename_template[0])
 531                         filename_template = origtemplate;
 532
 533                 nonrelative_template = absolute_path(filename_template);
 534                 errno = saved_errno;
 535                 die_errno("Unable to create temporary file '%s'",
 536                         nonrelative_template);
 537         }
 538         return fd;
 539 }
 540
 541 static int warn_if_unremovable(const char *op, const char *file, int rc)
 542 {
 543         int err;
 544         if (!rc || errno == ENOENT)
 545                 return 0;
 546         err = errno;
 547         warning_errno("unable to %s '%s'", op, file);
 548         errno = err;
 549         return rc;
 550 }
 551
 552 int unlink_or_msg(const char *file, struct strbuf *err)
 553 {
 554         int rc = unlink(file);
 555
 556         assert(err);
 557
 558         if (!rc || errno == ENOENT)
 559                 return 0;
 560
 561         strbuf_addf(err, "unable to unlink '%s': %s",
 562                     file, strerror(errno));
 563         return -1;
 564 }
 565
 566 int unlink_or_warn(const char *file)
 567 {
 568         return warn_if_unremovable("unlink", file, unlink(file));
 569 }
 570
 571 int rmdir_or_warn(const char *file)
 572 {
 573         return warn_if_unremovable("rmdir", file, rmdir(file));
 574 }
 575
 576 int remove_or_warn(unsigned int mode, const char *file)
 577 {
 578         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 579 }
 580
 581 static int access_error_is_ok(int err, unsigned flag)
 582 {
 583         return (is_missing_file_error(err) ||
 584                 ((flag & ACCESS_EACCES_OK) && err == EACCES));
 585 }
 586
 587 int access_or_warn(const char *path, int mode, unsigned flag)
 588 {
 589         int ret = access(path, mode);
 590         if (ret && !access_error_is_ok(errno, flag))
 591                 warn_on_inaccessible(path);
 592         return ret;
 593 }
 594
 595 int access_or_die(const char *path, int mode, unsigned flag)
 596 {
 597         int ret = access(path, mode);
 598         if (ret && !access_error_is_ok(errno, flag))
 599                 die_errno(_("unable to access '%s'"), path);
 600         return ret;
 601 }
 602
 603 char *xgetcwd(void)
 604 {
 605         struct strbuf sb = STRBUF_INIT;
 606         if (strbuf_getcwd(&sb))
 607                 die_errno(_("unable to get current working directory"));
 608         return strbuf_detach(&sb, NULL);
 609 }
 610
 611 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
 612 {
 613         va_list ap;
 614         int len;
 615
 616         va_start(ap, fmt);
 617         len = vsnprintf(dst, max, fmt, ap);
 618         va_end(ap);
 619
 620         if (len < 0)
 621                 BUG("your snprintf is broken");
 622         if (len >= max)
 623                 BUG("attempt to snprintf into too-small buffer");
 624         return len;
 625 }
 626
 627 void write_file_buf(const char *path, const char *buf, size_t len)
 628 {
 629         int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 630         if (write_in_full(fd, buf, len) < 0)
 631                 die_errno(_("could not write to '%s'"), path);
 632         if (close(fd))
 633                 die_errno(_("could not close '%s'"), path);
 634 }
 635
 636 void write_file(const char *path, const char *fmt, ...)
 637 {
 638         va_list params;
 639         struct strbuf sb = STRBUF_INIT;
 640
 641         va_start(params, fmt);
 642         strbuf_vaddf(&sb, fmt, params);
 643         va_end(params);
 644
 645         strbuf_complete_line(&sb);
 646
 647         write_file_buf(path, sb.buf, sb.len);
 648         strbuf_release(&sb);
 649 }
 650
 651 void sleep_millisec(int millisec)
 652 {
 653         poll(NULL, 0, millisec);
 654 }
 655
 656 int xgethostname(char *buf, size_t len)
 657 {
 658         /*
 659          * If the full hostname doesn't fit in buf, POSIX does not
 660          * specify whether the buffer will be null-terminated, so to
 661          * be safe, do it ourselves.
 662          */
 663         int ret = gethostname(buf, len);
 664         if (!ret)
 665                 buf[len - 1] = 0;
 666         return ret;
 667 }
 668
 669 int is_empty_or_missing_file(const char *filename)
 670 {
 671         struct stat st;
 672
 673         if (stat(filename, &st) < 0) {
 674                 if (errno == ENOENT)
 675                         return 1;
 676                 die_errno(_("could not stat %s"), filename);
 677         }
 678
 679         return !st.st_size;
 680 }
 681
 682 int open_nofollow(const char *path, int flags)
 683 {
 684 #ifdef O_NOFOLLOW
 685         return open(path, flags | O_NOFOLLOW);
 686 #else
 687         struct stat st;
 688         if (lstat(path, &st) < 0)
 689                 return -1;
 690         if (S_ISLNK(st.st_mode)) {
 691                 errno = ELOOP;
 692                 return -1;
 693         }
 694         return open(path, flags);
 695 #endif
 696 }