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         if (unsigned_mult_overflows(nmemb, size))
 156                 die("data too large to fit into virtual memory space");
 157
 158         memory_limit_check(size * nmemb, 0);
 159         ret = calloc(nmemb, size);
 160         if (!ret && (!nmemb || !size))
 161                 ret = calloc(1, 1);
 162         if (!ret) {
 163                 try_to_free_routine(nmemb * size);
 164                 ret = calloc(nmemb, size);
 165                 if (!ret && (!nmemb || !size))
 166                         ret = calloc(1, 1);
 167                 if (!ret)
 168                         die("Out of memory, calloc failed");
 169         }
 170         return ret;
 171 }
 172
 173 /*
 174  * Limit size of IO chunks, because huge chunks only cause pain.  OS X
 175  * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
 176  * the absence of bugs, large chunks can result in bad latencies when
 177  * you decide to kill the process.
 178  *
 179  * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
 180  * that is smaller than that, clip it to SSIZE_MAX, as a call to
 181  * read(2) or write(2) larger than that is allowed to fail.  As the last
 182  * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
 183  * to override this, if the definition of SSIZE_MAX given by the platform
 184  * is broken.
 185  */
 186 #ifndef MAX_IO_SIZE
 187 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
 188 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
 189 #  define MAX_IO_SIZE SSIZE_MAX
 190 # else
 191 #  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
 192 # endif
 193 #endif
 194
 195 /**
 196  * xopen() is the same as open(), but it die()s if the open() fails.
 197  */
 198 int xopen(const char *path, int oflag, ...)
 199 {
 200         mode_t mode = 0;
 201         va_list ap;
 202
 203         /*
 204          * va_arg() will have undefined behavior if the specified type is not
 205          * compatible with the argument type. Since integers are promoted to
 206          * ints, we fetch the next argument as an int, and then cast it to a
 207          * mode_t to avoid undefined behavior.
 208          */
 209         va_start(ap, oflag);
 210         if (oflag & O_CREAT)
 211                 mode = va_arg(ap, int);
 212         va_end(ap);
 213
 214         for (;;) {
 215                 int fd = open(path, oflag, mode);
 216                 if (fd >= 0)
 217                         return fd;
 218                 if (errno == EINTR)
 219                         continue;
 220
 221                 if ((oflag & O_RDWR) == O_RDWR)
 222                         die_errno(_("could not open '%s' for reading and writing"), path);
 223                 else if ((oflag & O_WRONLY) == O_WRONLY)
 224                         die_errno(_("could not open '%s' for writing"), path);
 225                 else
 226                         die_errno(_("could not open '%s' for reading"), path);
 227         }
 228 }
 229
 230 static int handle_nonblock(int fd, short poll_events, int err)
 231 {
 232         struct pollfd pfd;
 233
 234         if (err != EAGAIN && err != EWOULDBLOCK)
 235                 return 0;
 236
 237         pfd.fd = fd;
 238         pfd.events = poll_events;
 239
 240         /*
 241          * no need to check for errors, here;
 242          * a subsequent read/write will detect unrecoverable errors
 243          */
 244         poll(&pfd, 1, -1);
 245         return 1;
 246 }
 247
 248 /*
 249  * xread() is the same a read(), but it automatically restarts read()
 250  * operations with a recoverable error (EAGAIN and EINTR). xread()
 251  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 252  */
 253 ssize_t xread(int fd, void *buf, size_t len)
 254 {
 255         ssize_t nr;
 256         if (len > MAX_IO_SIZE)
 257             len = MAX_IO_SIZE;
 258         while (1) {
 259                 nr = read(fd, buf, len);
 260                 if (nr < 0) {
 261                         if (errno == EINTR)
 262                                 continue;
 263                         if (handle_nonblock(fd, POLLIN, errno))
 264                                 continue;
 265                 }
 266                 return nr;
 267         }
 268 }
 269
 270 /*
 271  * xwrite() is the same a write(), but it automatically restarts write()
 272  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 273  * GUARANTEE that "len" bytes is written even if the operation is successful.
 274  */
 275 ssize_t xwrite(int fd, const void *buf, size_t len)
 276 {
 277         ssize_t nr;
 278         if (len > MAX_IO_SIZE)
 279             len = MAX_IO_SIZE;
 280         while (1) {
 281                 nr = write(fd, buf, len);
 282                 if (nr < 0) {
 283                         if (errno == EINTR)
 284                                 continue;
 285                         if (handle_nonblock(fd, POLLOUT, errno))
 286                                 continue;
 287                 }
 288
 289                 return nr;
 290         }
 291 }
 292
 293 /*
 294  * xpread() is the same as pread(), but it automatically restarts pread()
 295  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 296  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 297  */
 298 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 299 {
 300         ssize_t nr;
 301         if (len > MAX_IO_SIZE)
 302                 len = MAX_IO_SIZE;
 303         while (1) {
 304                 nr = pread(fd, buf, len, offset);
 305                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 306                         continue;
 307                 return nr;
 308         }
 309 }
 310
 311 ssize_t read_in_full(int fd, void *buf, size_t count)
 312 {
 313         char *p = buf;
 314         ssize_t total = 0;
 315
 316         while (count > 0) {
 317                 ssize_t loaded = xread(fd, p, count);
 318                 if (loaded < 0)
 319                         return -1;
 320                 if (loaded == 0)
 321                         return total;
 322                 count -= loaded;
 323                 p += loaded;
 324                 total += loaded;
 325         }
 326
 327         return total;
 328 }
 329
 330 ssize_t write_in_full(int fd, const void *buf, size_t count)
 331 {
 332         const char *p = buf;
 333         ssize_t total = 0;
 334
 335         while (count > 0) {
 336                 ssize_t written = xwrite(fd, p, count);
 337                 if (written < 0)
 338                         return -1;
 339                 if (!written) {
 340                         errno = ENOSPC;
 341                         return -1;
 342                 }
 343                 count -= written;
 344                 p += written;
 345                 total += written;
 346         }
 347
 348         return total;
 349 }
 350
 351 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 352 {
 353         char *p = buf;
 354         ssize_t total = 0;
 355
 356         while (count > 0) {
 357                 ssize_t loaded = xpread(fd, p, count, offset);
 358                 if (loaded < 0)
 359                         return -1;
 360                 if (loaded == 0)
 361                         return total;
 362                 count -= loaded;
 363                 p += loaded;
 364                 total += loaded;
 365                 offset += loaded;
 366         }
 367
 368         return total;
 369 }
 370
 371 int xdup(int fd)
 372 {
 373         int ret = dup(fd);
 374         if (ret < 0)
 375                 die_errno("dup failed");
 376         return ret;
 377 }
 378
 379 /**
 380  * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
 381  */
 382 FILE *xfopen(const char *path, const char *mode)
 383 {
 384         for (;;) {
 385                 FILE *fp = fopen(path, mode);
 386                 if (fp)
 387                         return fp;
 388                 if (errno == EINTR)
 389                         continue;
 390
 391                 if (*mode && mode[1] == '+')
 392                         die_errno(_("could not open '%s' for reading and writing"), path);
 393                 else if (*mode == 'w' || *mode == 'a')
 394                         die_errno(_("could not open '%s' for writing"), path);
 395                 else
 396                         die_errno(_("could not open '%s' for reading"), path);
 397         }
 398 }
 399
 400 FILE *xfdopen(int fd, const char *mode)
 401 {
 402         FILE *stream = fdopen(fd, mode);
 403         if (stream == NULL)
 404                 die_errno("Out of memory? fdopen failed");
 405         return stream;
 406 }
 407
 408 FILE *fopen_for_writing(const char *path)
 409 {
 410         FILE *ret = fopen(path, "w");
 411
 412         if (!ret && errno == EPERM) {
 413                 if (!unlink(path))
 414                         ret = fopen(path, "w");
 415                 else
 416                         errno = EPERM;
 417         }
 418         return ret;
 419 }
 420
 421 int xmkstemp(char *template)
 422 {
 423         int fd;
 424         char origtemplate[PATH_MAX];
 425         strlcpy(origtemplate, template, sizeof(origtemplate));
 426
 427         fd = mkstemp(template);
 428         if (fd < 0) {
 429                 int saved_errno = errno;
 430                 const char *nonrelative_template;
 431
 432                 if (strlen(template) != strlen(origtemplate))
 433                         template = origtemplate;
 434
 435                 nonrelative_template = absolute_path(template);
 436                 errno = saved_errno;
 437                 die_errno("Unable to create temporary file '%s'",
 438                         nonrelative_template);
 439         }
 440         return fd;
 441 }
 442
 443 /* Adapted from libiberty's mkstemp.c. */
 444
 445 #undef TMP_MAX
 446 #define TMP_MAX 16384
 447
 448 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 449 {
 450         static const char letters[] =
 451                 "abcdefghijklmnopqrstuvwxyz"
 452                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 453                 "0123456789";
 454         static const int num_letters = 62;
 455         uint64_t value;
 456         struct timeval tv;
 457         char *template;
 458         size_t len;
 459         int fd, count;
 460
 461         len = strlen(pattern);
 462
 463         if (len < 6 + suffix_len) {
 464                 errno = EINVAL;
 465                 return -1;
 466         }
 467
 468         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 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 = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 479         template = &pattern[len - 6 - suffix_len];
 480         for (count = 0; count < TMP_MAX; ++count) {
 481                 uint64_t v = value;
 482                 /* Fill in the random bits. */
 483                 template[0] = letters[v % num_letters]; v /= num_letters;
 484                 template[1] = letters[v % num_letters]; v /= num_letters;
 485                 template[2] = letters[v % num_letters]; v /= num_letters;
 486                 template[3] = letters[v % num_letters]; v /= num_letters;
 487                 template[4] = letters[v % num_letters]; v /= num_letters;
 488                 template[5] = letters[v % num_letters]; v /= num_letters;
 489
 490                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 491                 if (fd >= 0)
 492                         return fd;
 493                 /*
 494                  * Fatal error (EPERM, ENOSPC etc).
 495                  * It doesn't make sense to loop.
 496                  */
 497                 if (errno != EEXIST)
 498                         break;
 499                 /*
 500                  * This is a random value.  It is only necessary that
 501                  * the next TMP_MAX values generated by adding 7777 to
 502                  * VALUE are different with (module 2^32).
 503                  */
 504                 value += 7777;
 505         }
 506         /* We return the null string if we can't find a unique file name.  */
 507         pattern[0] = '\0';
 508         return -1;
 509 }
 510
 511 int git_mkstemp_mode(char *pattern, int mode)
 512 {
 513         /* mkstemp is just mkstemps with no suffix */
 514         return git_mkstemps_mode(pattern, 0, mode);
 515 }
 516
 517 int xmkstemp_mode(char *template, int mode)
 518 {
 519         int fd;
 520         char origtemplate[PATH_MAX];
 521         strlcpy(origtemplate, template, sizeof(origtemplate));
 522
 523         fd = git_mkstemp_mode(template, mode);
 524         if (fd < 0) {
 525                 int saved_errno = errno;
 526                 const char *nonrelative_template;
 527
 528                 if (!template[0])
 529                         template = origtemplate;
 530
 531                 nonrelative_template = absolute_path(template);
 532                 errno = saved_errno;
 533                 die_errno("Unable to create temporary file '%s'",
 534                         nonrelative_template);
 535         }
 536         return fd;
 537 }
 538
 539 static int warn_if_unremovable(const char *op, const char *file, int rc)
 540 {
 541         int err;
 542         if (!rc || errno == ENOENT)
 543                 return 0;
 544         err = errno;
 545         warning_errno("unable to %s %s", op, file);
 546         errno = err;
 547         return rc;
 548 }
 549
 550 int unlink_or_msg(const char *file, struct strbuf *err)
 551 {
 552         int rc = unlink(file);
 553
 554         assert(err);
 555
 556         if (!rc || errno == ENOENT)
 557                 return 0;
 558
 559         strbuf_addf(err, "unable to unlink %s: %s",
 560                     file, strerror(errno));
 561         return -1;
 562 }
 563
 564 int unlink_or_warn(const char *file)
 565 {
 566         return warn_if_unremovable("unlink", file, unlink(file));
 567 }
 568
 569 int rmdir_or_warn(const char *file)
 570 {
 571         return warn_if_unremovable("rmdir", file, rmdir(file));
 572 }
 573
 574 int remove_or_warn(unsigned int mode, const char *file)
 575 {
 576         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 577 }
 578
 579 void warn_on_inaccessible(const char *path)
 580 {
 581         warning_errno(_("unable to access '%s'"), path);
 582 }
 583
 584 static int access_error_is_ok(int err, unsigned flag)
 585 {
 586         return err == ENOENT || err == ENOTDIR ||
 587                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 588 }
 589
 590 int access_or_warn(const char *path, int mode, unsigned flag)
 591 {
 592         int ret = access(path, mode);
 593         if (ret && !access_error_is_ok(errno, flag))
 594                 warn_on_inaccessible(path);
 595         return ret;
 596 }
 597
 598 int access_or_die(const char *path, int mode, unsigned flag)
 599 {
 600         int ret = access(path, mode);
 601         if (ret && !access_error_is_ok(errno, flag))
 602                 die_errno(_("unable to access '%s'"), path);
 603         return ret;
 604 }
 605
 606 char *xgetcwd(void)
 607 {
 608         struct strbuf sb = STRBUF_INIT;
 609         if (strbuf_getcwd(&sb))
 610                 die_errno(_("unable to get current working directory"));
 611         return strbuf_detach(&sb, NULL);
 612 }
 613
 614 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
 615 {
 616         va_list ap;
 617         int len;
 618
 619         va_start(ap, fmt);
 620         len = vsnprintf(dst, max, fmt, ap);
 621         va_end(ap);
 622
 623         if (len < 0)
 624                 die("BUG: your snprintf is broken");
 625         if (len >= max)
 626                 die("BUG: attempt to snprintf into too-small buffer");
 627         return len;
 628 }
 629
 630 void write_file_buf(const char *path, const char *buf, size_t len)
 631 {
 632         int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 633         if (write_in_full(fd, buf, len) != len)
 634                 die_errno(_("could not write to %s"), path);
 635         if (close(fd))
 636                 die_errno(_("could not close %s"), path);
 637 }
 638
 639 void write_file(const char *path, const char *fmt, ...)
 640 {
 641         va_list params;
 642         struct strbuf sb = STRBUF_INIT;
 643
 644         va_start(params, fmt);
 645         strbuf_vaddf(&sb, fmt, params);
 646         va_end(params);
 647
 648         strbuf_complete_line(&sb);
 649
 650         write_file_buf(path, sb.buf, sb.len);
 651         strbuf_release(&sb);
 652 }
 653
 654 void sleep_millisec(int millisec)
 655 {
 656         poll(NULL, 0, millisec);
 657 }