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