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         memory_limit_check(size * nmemb, 0);
 156         ret = calloc(nmemb, size);
 157         if (!ret && (!nmemb || !size))
 158                 ret = calloc(1, 1);
 159         if (!ret) {
 160                 try_to_free_routine(nmemb * size);
 161                 ret = calloc(nmemb, size);
 162                 if (!ret && (!nmemb || !size))
 163                         ret = calloc(1, 1);
 164                 if (!ret)
 165                         die("Out of memory, calloc failed");
 166         }
 167         return ret;
 168 }
 169
 170 /*
 171  * Limit size of IO chunks, because huge chunks only cause pain.  OS X
 172  * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
 173  * the absence of bugs, large chunks can result in bad latencies when
 174  * you decide to kill the process.
 175  *
 176  * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
 177  * that is smaller than that, clip it to SSIZE_MAX, as a call to
 178  * read(2) or write(2) larger than that is allowed to fail.  As the last
 179  * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
 180  * to override this, if the definition of SSIZE_MAX given by the platform
 181  * is broken.
 182  */
 183 #ifndef MAX_IO_SIZE
 184 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
 185 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
 186 #  define MAX_IO_SIZE SSIZE_MAX
 187 # else
 188 #  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
 189 # endif
 190 #endif
 191
 192 /**
 193  * xopen() is the same as open(), but it die()s if the open() fails.
 194  */
 195 int xopen(const char *path, int oflag, ...)
 196 {
 197         mode_t mode = 0;
 198         va_list ap;
 199
 200         /*
 201          * va_arg() will have undefined behavior if the specified type is not
 202          * compatible with the argument type. Since integers are promoted to
 203          * ints, we fetch the next argument as an int, and then cast it to a
 204          * mode_t to avoid undefined behavior.
 205          */
 206         va_start(ap, oflag);
 207         if (oflag & O_CREAT)
 208                 mode = va_arg(ap, int);
 209         va_end(ap);
 210
 211         for (;;) {
 212                 int fd = open(path, oflag, mode);
 213                 if (fd >= 0)
 214                         return fd;
 215                 if (errno == EINTR)
 216                         continue;
 217
 218                 if ((oflag & O_RDWR) == O_RDWR)
 219                         die_errno(_("could not open '%s' for reading and writing"), path);
 220                 else if ((oflag & O_WRONLY) == O_WRONLY)
 221                         die_errno(_("could not open '%s' for writing"), path);
 222                 else
 223                         die_errno(_("could not open '%s' for reading"), path);
 224         }
 225 }
 226
 227 /*
 228  * xread() is the same a read(), but it automatically restarts read()
 229  * operations with a recoverable error (EAGAIN and EINTR). xread()
 230  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 231  */
 232 ssize_t xread(int fd, void *buf, size_t len)
 233 {
 234         ssize_t nr;
 235         if (len > MAX_IO_SIZE)
 236             len = MAX_IO_SIZE;
 237         while (1) {
 238                 nr = read(fd, buf, len);
 239                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 240                         continue;
 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) && (errno == EAGAIN || errno == EINTR))
 258                         continue;
 259                 return nr;
 260         }
 261 }
 262
 263 /*
 264  * xpread() is the same as pread(), but it automatically restarts pread()
 265  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 266  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 267  */
 268 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 269 {
 270         ssize_t nr;
 271         if (len > MAX_IO_SIZE)
 272                 len = MAX_IO_SIZE;
 273         while (1) {
 274                 nr = pread(fd, buf, len, offset);
 275                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 276                         continue;
 277                 return nr;
 278         }
 279 }
 280
 281 ssize_t read_in_full(int fd, void *buf, size_t count)
 282 {
 283         char *p = buf;
 284         ssize_t total = 0;
 285
 286         while (count > 0) {
 287                 ssize_t loaded = xread(fd, p, count);
 288                 if (loaded < 0)
 289                         return -1;
 290                 if (loaded == 0)
 291                         return total;
 292                 count -= loaded;
 293                 p += loaded;
 294                 total += loaded;
 295         }
 296
 297         return total;
 298 }
 299
 300 ssize_t write_in_full(int fd, const void *buf, size_t count)
 301 {
 302         const char *p = buf;
 303         ssize_t total = 0;
 304
 305         while (count > 0) {
 306                 ssize_t written = xwrite(fd, p, count);
 307                 if (written < 0)
 308                         return -1;
 309                 if (!written) {
 310                         errno = ENOSPC;
 311                         return -1;
 312                 }
 313                 count -= written;
 314                 p += written;
 315                 total += written;
 316         }
 317
 318         return total;
 319 }
 320
 321 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 322 {
 323         char *p = buf;
 324         ssize_t total = 0;
 325
 326         while (count > 0) {
 327                 ssize_t loaded = xpread(fd, p, count, offset);
 328                 if (loaded < 0)
 329                         return -1;
 330                 if (loaded == 0)
 331                         return total;
 332                 count -= loaded;
 333                 p += loaded;
 334                 total += loaded;
 335                 offset += loaded;
 336         }
 337
 338         return total;
 339 }
 340
 341 int xdup(int fd)
 342 {
 343         int ret = dup(fd);
 344         if (ret < 0)
 345                 die_errno("dup failed");
 346         return ret;
 347 }
 348
 349 FILE *xfdopen(int fd, const char *mode)
 350 {
 351         FILE *stream = fdopen(fd, mode);
 352         if (stream == NULL)
 353                 die_errno("Out of memory? fdopen failed");
 354         return stream;
 355 }
 356
 357 int xmkstemp(char *template)
 358 {
 359         int fd;
 360         char origtemplate[PATH_MAX];
 361         strlcpy(origtemplate, template, sizeof(origtemplate));
 362
 363         fd = mkstemp(template);
 364         if (fd < 0) {
 365                 int saved_errno = errno;
 366                 const char *nonrelative_template;
 367
 368                 if (strlen(template) != strlen(origtemplate))
 369                         template = origtemplate;
 370
 371                 nonrelative_template = absolute_path(template);
 372                 errno = saved_errno;
 373                 die_errno("Unable to create temporary file '%s'",
 374                         nonrelative_template);
 375         }
 376         return fd;
 377 }
 378
 379 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 380 int git_mkstemp(char *path, size_t len, const char *template)
 381 {
 382         const char *tmp;
 383         size_t n;
 384
 385         tmp = getenv("TMPDIR");
 386         if (!tmp)
 387                 tmp = "/tmp";
 388         n = snprintf(path, len, "%s/%s", tmp, template);
 389         if (len <= n) {
 390                 errno = ENAMETOOLONG;
 391                 return -1;
 392         }
 393         return mkstemp(path);
 394 }
 395
 396 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 397 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 398 {
 399         const char *tmp;
 400         size_t n;
 401
 402         tmp = getenv("TMPDIR");
 403         if (!tmp)
 404                 tmp = "/tmp";
 405         n = snprintf(path, len, "%s/%s", tmp, template);
 406         if (len <= n) {
 407                 errno = ENAMETOOLONG;
 408                 return -1;
 409         }
 410         return mkstemps(path, suffix_len);
 411 }
 412
 413 /* Adapted from libiberty's mkstemp.c. */
 414
 415 #undef TMP_MAX
 416 #define TMP_MAX 16384
 417
 418 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 419 {
 420         static const char letters[] =
 421                 "abcdefghijklmnopqrstuvwxyz"
 422                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 423                 "0123456789";
 424         static const int num_letters = 62;
 425         uint64_t value;
 426         struct timeval tv;
 427         char *template;
 428         size_t len;
 429         int fd, count;
 430
 431         len = strlen(pattern);
 432
 433         if (len < 6 + suffix_len) {
 434                 errno = EINVAL;
 435                 return -1;
 436         }
 437
 438         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 439                 errno = EINVAL;
 440                 return -1;
 441         }
 442
 443         /*
 444          * Replace pattern's XXXXXX characters with randomness.
 445          * Try TMP_MAX different filenames.
 446          */
 447         gettimeofday(&tv, NULL);
 448         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 449         template = &pattern[len - 6 - suffix_len];
 450         for (count = 0; count < TMP_MAX; ++count) {
 451                 uint64_t v = value;
 452                 /* Fill in the random bits. */
 453                 template[0] = letters[v % num_letters]; v /= num_letters;
 454                 template[1] = letters[v % num_letters]; v /= num_letters;
 455                 template[2] = letters[v % num_letters]; v /= num_letters;
 456                 template[3] = letters[v % num_letters]; v /= num_letters;
 457                 template[4] = letters[v % num_letters]; v /= num_letters;
 458                 template[5] = letters[v % num_letters]; v /= num_letters;
 459
 460                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 461                 if (fd >= 0)
 462                         return fd;
 463                 /*
 464                  * Fatal error (EPERM, ENOSPC etc).
 465                  * It doesn't make sense to loop.
 466                  */
 467                 if (errno != EEXIST)
 468                         break;
 469                 /*
 470                  * This is a random value.  It is only necessary that
 471                  * the next TMP_MAX values generated by adding 7777 to
 472                  * VALUE are different with (module 2^32).
 473                  */
 474                 value += 7777;
 475         }
 476         /* We return the null string if we can't find a unique file name.  */
 477         pattern[0] = '\0';
 478         return -1;
 479 }
 480
 481 int git_mkstemp_mode(char *pattern, int mode)
 482 {
 483         /* mkstemp is just mkstemps with no suffix */
 484         return git_mkstemps_mode(pattern, 0, mode);
 485 }
 486
 487 #ifdef NO_MKSTEMPS
 488 int gitmkstemps(char *pattern, int suffix_len)
 489 {
 490         return git_mkstemps_mode(pattern, suffix_len, 0600);
 491 }
 492 #endif
 493
 494 int xmkstemp_mode(char *template, int mode)
 495 {
 496         int fd;
 497         char origtemplate[PATH_MAX];
 498         strlcpy(origtemplate, template, sizeof(origtemplate));
 499
 500         fd = git_mkstemp_mode(template, mode);
 501         if (fd < 0) {
 502                 int saved_errno = errno;
 503                 const char *nonrelative_template;
 504
 505                 if (!template[0])
 506                         template = origtemplate;
 507
 508                 nonrelative_template = absolute_path(template);
 509                 errno = saved_errno;
 510                 die_errno("Unable to create temporary file '%s'",
 511                         nonrelative_template);
 512         }
 513         return fd;
 514 }
 515
 516 static int warn_if_unremovable(const char *op, const char *file, int rc)
 517 {
 518         int err;
 519         if (!rc || errno == ENOENT)
 520                 return 0;
 521         err = errno;
 522         warning("unable to %s %s: %s", op, file, strerror(errno));
 523         errno = err;
 524         return rc;
 525 }
 526
 527 int unlink_or_msg(const char *file, struct strbuf *err)
 528 {
 529         int rc = unlink(file);
 530
 531         assert(err);
 532
 533         if (!rc || errno == ENOENT)
 534                 return 0;
 535
 536         strbuf_addf(err, "unable to unlink %s: %s",
 537                     file, strerror(errno));
 538         return -1;
 539 }
 540
 541 int unlink_or_warn(const char *file)
 542 {
 543         return warn_if_unremovable("unlink", file, unlink(file));
 544 }
 545
 546 int rmdir_or_warn(const char *file)
 547 {
 548         return warn_if_unremovable("rmdir", file, rmdir(file));
 549 }
 550
 551 int remove_or_warn(unsigned int mode, const char *file)
 552 {
 553         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 554 }
 555
 556 void warn_on_inaccessible(const char *path)
 557 {
 558         warning(_("unable to access '%s': %s"), path, strerror(errno));
 559 }
 560
 561 static int access_error_is_ok(int err, unsigned flag)
 562 {
 563         return err == ENOENT || err == ENOTDIR ||
 564                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 565 }
 566
 567 int access_or_warn(const char *path, int mode, unsigned flag)
 568 {
 569         int ret = access(path, mode);
 570         if (ret && !access_error_is_ok(errno, flag))
 571                 warn_on_inaccessible(path);
 572         return ret;
 573 }
 574
 575 int access_or_die(const char *path, int mode, unsigned flag)
 576 {
 577         int ret = access(path, mode);
 578         if (ret && !access_error_is_ok(errno, flag))
 579                 die_errno(_("unable to access '%s'"), path);
 580         return ret;
 581 }
 582
 583 struct passwd *xgetpwuid_self(void)
 584 {
 585         struct passwd *pw;
 586
 587         errno = 0;
 588         pw = getpwuid(getuid());
 589         if (!pw)
 590                 die(_("unable to look up current user in the passwd file: %s"),
 591                     errno ? strerror(errno) : _("no such user"));
 592         return pw;
 593 }
 594
 595 char *xgetcwd(void)
 596 {
 597         struct strbuf sb = STRBUF_INIT;
 598         if (strbuf_getcwd(&sb))
 599                 die_errno(_("unable to get current working directory"));
 600         return strbuf_detach(&sb, NULL);
 601 }
 602
 603 int write_file(const char *path, int fatal, const char *fmt, ...)
 604 {
 605         struct strbuf sb = STRBUF_INIT;
 606         va_list params;
 607         int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666);
 608         if (fd < 0) {
 609                 if (fatal)
 610                         die_errno(_("could not open %s for writing"), path);
 611                 return -1;
 612         }
 613         va_start(params, fmt);
 614         strbuf_vaddf(&sb, fmt, params);
 615         va_end(params);
 616         if (write_in_full(fd, sb.buf, sb.len) != sb.len) {
 617                 int err = errno;
 618                 close(fd);
 619                 strbuf_release(&sb);
 620                 errno = err;
 621                 if (fatal)
 622                         die_errno(_("could not write to %s"), path);
 623                 return -1;
 624         }
 625         strbuf_release(&sb);
 626         if (close(fd)) {
 627                 if (fatal)
 628                         die_errno(_("could not close %s"), path);
 629                 return -1;
 630         }
 631         return 0;
 632 }
 633
 634 void sleep_millisec(int millisec)
 635 {
 636         poll(NULL, 0, millisec);
 637 }