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 void xsetenv(const char *name, const char *value, int overwrite)
 149 {
 150         if (setenv(name, value, overwrite))
 151                 die_errno(_("could not setenv '%s'"), name ? name : "(null)");
 152 }
 153
 154 void xunsetenv(const char *name)
 155 {
 156         if (!unsetenv(name))
 157                 die_errno(_("could not unsetenv '%s'"), name ? name : "(null)");
 158 }
 159
 160 /*
 161  * Limit size of IO chunks, because huge chunks only cause pain.  OS X
 162  * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
 163  * the absence of bugs, large chunks can result in bad latencies when
 164  * you decide to kill the process.
 165  *
 166  * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
 167  * that is smaller than that, clip it to SSIZE_MAX, as a call to
 168  * read(2) or write(2) larger than that is allowed to fail.  As the last
 169  * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
 170  * to override this, if the definition of SSIZE_MAX given by the platform
 171  * is broken.
 172  */
 173 #ifndef MAX_IO_SIZE
 174 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
 175 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
 176 #  define MAX_IO_SIZE SSIZE_MAX
 177 # else
 178 #  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
 179 # endif
 180 #endif
 181
 182 /**
 183  * xopen() is the same as open(), but it die()s if the open() fails.
 184  */
 185 int xopen(const char *path, int oflag, ...)
 186 {
 187         mode_t mode = 0;
 188         va_list ap;
 189
 190         /*
 191          * va_arg() will have undefined behavior if the specified type is not
 192          * compatible with the argument type. Since integers are promoted to
 193          * ints, we fetch the next argument as an int, and then cast it to a
 194          * mode_t to avoid undefined behavior.
 195          */
 196         va_start(ap, oflag);
 197         if (oflag & O_CREAT)
 198                 mode = va_arg(ap, int);
 199         va_end(ap);
 200
 201         for (;;) {
 202                 int fd = open(path, oflag, mode);
 203                 if (fd >= 0)
 204                         return fd;
 205                 if (errno == EINTR)
 206                         continue;
 207
 208                 if ((oflag & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
 209                         die_errno(_("unable to create '%s'"), path);
 210                 else if ((oflag & O_RDWR) == O_RDWR)
 211                         die_errno(_("could not open '%s' for reading and writing"), path);
 212                 else if ((oflag & O_WRONLY) == O_WRONLY)
 213                         die_errno(_("could not open '%s' for writing"), path);
 214                 else
 215                         die_errno(_("could not open '%s' for reading"), path);
 216         }
 217 }
 218
 219 static int handle_nonblock(int fd, short poll_events, int err)
 220 {
 221         struct pollfd pfd;
 222
 223         if (err != EAGAIN && err != EWOULDBLOCK)
 224                 return 0;
 225
 226         pfd.fd = fd;
 227         pfd.events = poll_events;
 228
 229         /*
 230          * no need to check for errors, here;
 231          * a subsequent read/write will detect unrecoverable errors
 232          */
 233         poll(&pfd, 1, -1);
 234         return 1;
 235 }
 236
 237 /*
 238  * xread() is the same a read(), but it automatically restarts read()
 239  * operations with a recoverable error (EAGAIN and EINTR). xread()
 240  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 241  */
 242 ssize_t xread(int fd, void *buf, size_t len)
 243 {
 244         ssize_t nr;
 245         if (len > MAX_IO_SIZE)
 246                 len = MAX_IO_SIZE;
 247         while (1) {
 248                 nr = read(fd, buf, len);
 249                 if (nr < 0) {
 250                         if (errno == EINTR)
 251                                 continue;
 252                         if (handle_nonblock(fd, POLLIN, errno))
 253                                 continue;
 254                 }
 255                 return nr;
 256         }
 257 }
 258
 259 /*
 260  * xwrite() is the same a write(), but it automatically restarts write()
 261  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 262  * GUARANTEE that "len" bytes is written even if the operation is successful.
 263  */
 264 ssize_t xwrite(int fd, const void *buf, size_t len)
 265 {
 266         ssize_t nr;
 267         if (len > MAX_IO_SIZE)
 268                 len = MAX_IO_SIZE;
 269         while (1) {
 270                 nr = write(fd, buf, len);
 271                 if (nr < 0) {
 272                         if (errno == EINTR)
 273                                 continue;
 274                         if (handle_nonblock(fd, POLLOUT, errno))
 275                                 continue;
 276                 }
 277
 278                 return nr;
 279         }
 280 }
 281
 282 /*
 283  * xpread() is the same as pread(), but it automatically restarts pread()
 284  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 285  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 286  */
 287 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 288 {
 289         ssize_t nr;
 290         if (len > MAX_IO_SIZE)
 291                 len = MAX_IO_SIZE;
 292         while (1) {
 293                 nr = pread(fd, buf, len, offset);
 294                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 295                         continue;
 296                 return nr;
 297         }
 298 }
 299
 300 ssize_t read_in_full(int fd, void *buf, size_t count)
 301 {
 302         char *p = buf;
 303         ssize_t total = 0;
 304
 305         while (count > 0) {
 306                 ssize_t loaded = xread(fd, p, count);
 307                 if (loaded < 0)
 308                         return -1;
 309                 if (loaded == 0)
 310                         return total;
 311                 count -= loaded;
 312                 p += loaded;
 313                 total += loaded;
 314         }
 315
 316         return total;
 317 }
 318
 319 ssize_t write_in_full(int fd, const void *buf, size_t count)
 320 {
 321         const char *p = buf;
 322         ssize_t total = 0;
 323
 324         while (count > 0) {
 325                 ssize_t written = xwrite(fd, p, count);
 326                 if (written < 0)
 327                         return -1;
 328                 if (!written) {
 329                         errno = ENOSPC;
 330                         return -1;
 331                 }
 332                 count -= written;
 333                 p += written;
 334                 total += written;
 335         }
 336
 337         return total;
 338 }
 339
 340 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 341 {
 342         char *p = buf;
 343         ssize_t total = 0;
 344
 345         while (count > 0) {
 346                 ssize_t loaded = xpread(fd, p, count, offset);
 347                 if (loaded < 0)
 348                         return -1;
 349                 if (loaded == 0)
 350                         return total;
 351                 count -= loaded;
 352                 p += loaded;
 353                 total += loaded;
 354                 offset += loaded;
 355         }
 356
 357         return total;
 358 }
 359
 360 int xdup(int fd)
 361 {
 362         int ret = dup(fd);
 363         if (ret < 0)
 364                 die_errno("dup failed");
 365         return ret;
 366 }
 367
 368 /**
 369  * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
 370  */
 371 FILE *xfopen(const char *path, const char *mode)
 372 {
 373         for (;;) {
 374                 FILE *fp = fopen(path, mode);
 375                 if (fp)
 376                         return fp;
 377                 if (errno == EINTR)
 378                         continue;
 379
 380                 if (*mode && mode[1] == '+')
 381                         die_errno(_("could not open '%s' for reading and writing"), path);
 382                 else if (*mode == 'w' || *mode == 'a')
 383                         die_errno(_("could not open '%s' for writing"), path);
 384                 else
 385                         die_errno(_("could not open '%s' for reading"), path);
 386         }
 387 }
 388
 389 FILE *xfdopen(int fd, const char *mode)
 390 {
 391         FILE *stream = fdopen(fd, mode);
 392         if (stream == NULL)
 393                 die_errno("Out of memory? fdopen failed");
 394         return stream;
 395 }
 396
 397 FILE *fopen_for_writing(const char *path)
 398 {
 399         FILE *ret = fopen(path, "w");
 400
 401         if (!ret && errno == EPERM) {
 402                 if (!unlink(path))
 403                         ret = fopen(path, "w");
 404                 else
 405                         errno = EPERM;
 406         }
 407         return ret;
 408 }
 409
 410 static void warn_on_inaccessible(const char *path)
 411 {
 412         warning_errno(_("unable to access '%s'"), path);
 413 }
 414
 415 int warn_on_fopen_errors(const char *path)
 416 {
 417         if (errno != ENOENT && errno != ENOTDIR) {
 418                 warn_on_inaccessible(path);
 419                 return -1;
 420         }
 421
 422         return 0;
 423 }
 424
 425 FILE *fopen_or_warn(const char *path, const char *mode)
 426 {
 427         FILE *fp = fopen(path, mode);
 428
 429         if (fp)
 430                 return fp;
 431
 432         warn_on_fopen_errors(path);
 433         return NULL;
 434 }
 435
 436 int xmkstemp(char *filename_template)
 437 {
 438         int fd;
 439         char origtemplate[PATH_MAX];
 440         strlcpy(origtemplate, filename_template, sizeof(origtemplate));
 441
 442         fd = mkstemp(filename_template);
 443         if (fd < 0) {
 444                 int saved_errno = errno;
 445                 const char *nonrelative_template;
 446
 447                 if (strlen(filename_template) != strlen(origtemplate))
 448                         filename_template = origtemplate;
 449
 450                 nonrelative_template = absolute_path(filename_template);
 451                 errno = saved_errno;
 452                 die_errno("Unable to create temporary file '%s'",
 453                         nonrelative_template);
 454         }
 455         return fd;
 456 }
 457
 458 /* Adapted from libiberty's mkstemp.c. */
 459
 460 #undef TMP_MAX
 461 #define TMP_MAX 16384
 462
 463 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 464 {
 465         static const char letters[] =
 466                 "abcdefghijklmnopqrstuvwxyz"
 467                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 468                 "0123456789";
 469         static const int num_letters = ARRAY_SIZE(letters) - 1;
 470         static const char x_pattern[] = "XXXXXX";
 471         static const int num_x = ARRAY_SIZE(x_pattern) - 1;
 472         uint64_t value;
 473         struct timeval tv;
 474         char *filename_template;
 475         size_t len;
 476         int fd, count;
 477
 478         len = strlen(pattern);
 479
 480         if (len < num_x + suffix_len) {
 481                 errno = EINVAL;
 482                 return -1;
 483         }
 484
 485         if (strncmp(&pattern[len - num_x - suffix_len], x_pattern, num_x)) {
 486                 errno = EINVAL;
 487                 return -1;
 488         }
 489
 490         /*
 491          * Replace pattern's XXXXXX characters with randomness.
 492          * Try TMP_MAX different filenames.
 493          */
 494         gettimeofday(&tv, NULL);
 495         value = ((uint64_t)tv.tv_usec << 16) ^ tv.tv_sec ^ getpid();
 496         filename_template = &pattern[len - num_x - suffix_len];
 497         for (count = 0; count < TMP_MAX; ++count) {
 498                 uint64_t v = value;
 499                 int i;
 500                 /* Fill in the random bits. */
 501                 for (i = 0; i < num_x; i++) {
 502                         filename_template[i] = letters[v % num_letters];
 503                         v /= num_letters;
 504                 }
 505
 506                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 507                 if (fd >= 0)
 508                         return fd;
 509                 /*
 510                  * Fatal error (EPERM, ENOSPC etc).
 511                  * It doesn't make sense to loop.
 512                  */
 513                 if (errno != EEXIST)
 514                         break;
 515                 /*
 516                  * This is a random value.  It is only necessary that
 517                  * the next TMP_MAX values generated by adding 7777 to
 518                  * VALUE are different with (module 2^32).
 519                  */
 520                 value += 7777;
 521         }
 522         /* We return the null string if we can't find a unique file name.  */
 523         pattern[0] = '\0';
 524         return -1;
 525 }
 526
 527 int git_mkstemp_mode(char *pattern, int mode)
 528 {
 529         /* mkstemp is just mkstemps with no suffix */
 530         return git_mkstemps_mode(pattern, 0, mode);
 531 }
 532
 533 int xmkstemp_mode(char *filename_template, int mode)
 534 {
 535         int fd;
 536         char origtemplate[PATH_MAX];
 537         strlcpy(origtemplate, filename_template, sizeof(origtemplate));
 538
 539         fd = git_mkstemp_mode(filename_template, mode);
 540         if (fd < 0) {
 541                 int saved_errno = errno;
 542                 const char *nonrelative_template;
 543
 544                 if (!filename_template[0])
 545                         filename_template = origtemplate;
 546
 547                 nonrelative_template = absolute_path(filename_template);
 548                 errno = saved_errno;
 549                 die_errno("Unable to create temporary file '%s'",
 550                         nonrelative_template);
 551         }
 552         return fd;
 553 }
 554
 555 static int warn_if_unremovable(const char *op, const char *file, int rc)
 556 {
 557         int err;
 558         if (!rc || errno == ENOENT)
 559                 return 0;
 560         err = errno;
 561         warning_errno("unable to %s '%s'", op, file);
 562         errno = err;
 563         return rc;
 564 }
 565
 566 int unlink_or_msg(const char *file, struct strbuf *err)
 567 {
 568         int rc = unlink(file);
 569
 570         assert(err);
 571
 572         if (!rc || errno == ENOENT)
 573                 return 0;
 574
 575         strbuf_addf(err, "unable to unlink '%s': %s",
 576                     file, strerror(errno));
 577         return -1;
 578 }
 579
 580 int unlink_or_warn(const char *file)
 581 {
 582         return warn_if_unremovable("unlink", file, unlink(file));
 583 }
 584
 585 int rmdir_or_warn(const char *file)
 586 {
 587         return warn_if_unremovable("rmdir", file, rmdir(file));
 588 }
 589
 590 int remove_or_warn(unsigned int mode, const char *file)
 591 {
 592         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 593 }
 594
 595 static int access_error_is_ok(int err, unsigned flag)
 596 {
 597         return (is_missing_file_error(err) ||
 598                 ((flag & ACCESS_EACCES_OK) && err == EACCES));
 599 }
 600
 601 int access_or_warn(const char *path, int mode, unsigned flag)
 602 {
 603         int ret = access(path, mode);
 604         if (ret && !access_error_is_ok(errno, flag))
 605                 warn_on_inaccessible(path);
 606         return ret;
 607 }
 608
 609 int access_or_die(const char *path, int mode, unsigned flag)
 610 {
 611         int ret = access(path, mode);
 612         if (ret && !access_error_is_ok(errno, flag))
 613                 die_errno(_("unable to access '%s'"), path);
 614         return ret;
 615 }
 616
 617 char *xgetcwd(void)
 618 {
 619         struct strbuf sb = STRBUF_INIT;
 620         if (strbuf_getcwd(&sb))
 621                 die_errno(_("unable to get current working directory"));
 622         return strbuf_detach(&sb, NULL);
 623 }
 624
 625 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
 626 {
 627         va_list ap;
 628         int len;
 629
 630         va_start(ap, fmt);
 631         len = vsnprintf(dst, max, fmt, ap);
 632         va_end(ap);
 633
 634         if (len < 0)
 635                 BUG("your snprintf is broken");
 636         if (len >= max)
 637                 BUG("attempt to snprintf into too-small buffer");
 638         return len;
 639 }
 640
 641 void write_file_buf(const char *path, const char *buf, size_t len)
 642 {
 643         int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 644         if (write_in_full(fd, buf, len) < 0)
 645                 die_errno(_("could not write to '%s'"), path);
 646         if (close(fd))
 647                 die_errno(_("could not close '%s'"), path);
 648 }
 649
 650 void write_file(const char *path, const char *fmt, ...)
 651 {
 652         va_list params;
 653         struct strbuf sb = STRBUF_INIT;
 654
 655         va_start(params, fmt);
 656         strbuf_vaddf(&sb, fmt, params);
 657         va_end(params);
 658
 659         strbuf_complete_line(&sb);
 660
 661         write_file_buf(path, sb.buf, sb.len);
 662         strbuf_release(&sb);
 663 }
 664
 665 void sleep_millisec(int millisec)
 666 {
 667         poll(NULL, 0, millisec);
 668 }
 669
 670 int xgethostname(char *buf, size_t len)
 671 {
 672         /*
 673          * If the full hostname doesn't fit in buf, POSIX does not
 674          * specify whether the buffer will be null-terminated, so to
 675          * be safe, do it ourselves.
 676          */
 677         int ret = gethostname(buf, len);
 678         if (!ret)
 679                 buf[len - 1] = 0;
 680         return ret;
 681 }
 682
 683 int is_empty_or_missing_file(const char *filename)
 684 {
 685         struct stat st;
 686
 687         if (stat(filename, &st) < 0) {
 688                 if (errno == ENOENT)
 689                         return 1;
 690                 die_errno(_("could not stat %s"), filename);
 691         }
 692
 693         return !st.st_size;
 694 }
 695
 696 int open_nofollow(const char *path, int flags)
 697 {
 698 #ifdef O_NOFOLLOW
 699         return open(path, flags | O_NOFOLLOW);
 700 #else
 701         struct stat st;
 702         if (lstat(path, &st) < 0)
 703                 return -1;
 704         if (S_ISLNK(st.st_mode)) {
 705                 errno = ELOOP;
 706                 return -1;
 707         }
 708         return open(path, flags);
 709 #endif
 710 }