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  * xread() is the same a read(), but it automatically restarts read()
 194  * operations with a recoverable error (EAGAIN and EINTR). xread()
 195  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 196  */
 197 ssize_t xread(int fd, void *buf, size_t len)
 198 {
 199         ssize_t nr;
 200         if (len > MAX_IO_SIZE)
 201             len = MAX_IO_SIZE;
 202         while (1) {
 203                 nr = read(fd, buf, len);
 204                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 205                         continue;
 206                 return nr;
 207         }
 208 }
 209
 210 /*
 211  * xwrite() is the same a write(), but it automatically restarts write()
 212  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 213  * GUARANTEE that "len" bytes is written even if the operation is successful.
 214  */
 215 ssize_t xwrite(int fd, const void *buf, size_t len)
 216 {
 217         ssize_t nr;
 218         if (len > MAX_IO_SIZE)
 219             len = MAX_IO_SIZE;
 220         while (1) {
 221                 nr = write(fd, buf, len);
 222                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 223                         continue;
 224                 return nr;
 225         }
 226 }
 227
 228 /*
 229  * xpread() is the same as pread(), but it automatically restarts pread()
 230  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 231  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 232  */
 233 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 234 {
 235         ssize_t nr;
 236         if (len > MAX_IO_SIZE)
 237                 len = MAX_IO_SIZE;
 238         while (1) {
 239                 nr = pread(fd, buf, len, offset);
 240                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 241                         continue;
 242                 return nr;
 243         }
 244 }
 245
 246 ssize_t read_in_full(int fd, void *buf, size_t count)
 247 {
 248         char *p = buf;
 249         ssize_t total = 0;
 250
 251         while (count > 0) {
 252                 ssize_t loaded = xread(fd, p, count);
 253                 if (loaded < 0)
 254                         return -1;
 255                 if (loaded == 0)
 256                         return total;
 257                 count -= loaded;
 258                 p += loaded;
 259                 total += loaded;
 260         }
 261
 262         return total;
 263 }
 264
 265 ssize_t write_in_full(int fd, const void *buf, size_t count)
 266 {
 267         const char *p = buf;
 268         ssize_t total = 0;
 269
 270         while (count > 0) {
 271                 ssize_t written = xwrite(fd, p, count);
 272                 if (written < 0)
 273                         return -1;
 274                 if (!written) {
 275                         errno = ENOSPC;
 276                         return -1;
 277                 }
 278                 count -= written;
 279                 p += written;
 280                 total += written;
 281         }
 282
 283         return total;
 284 }
 285
 286 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 287 {
 288         char *p = buf;
 289         ssize_t total = 0;
 290
 291         while (count > 0) {
 292                 ssize_t loaded = xpread(fd, p, count, offset);
 293                 if (loaded < 0)
 294                         return -1;
 295                 if (loaded == 0)
 296                         return total;
 297                 count -= loaded;
 298                 p += loaded;
 299                 total += loaded;
 300                 offset += loaded;
 301         }
 302
 303         return total;
 304 }
 305
 306 int xdup(int fd)
 307 {
 308         int ret = dup(fd);
 309         if (ret < 0)
 310                 die_errno("dup failed");
 311         return ret;
 312 }
 313
 314 FILE *xfdopen(int fd, const char *mode)
 315 {
 316         FILE *stream = fdopen(fd, mode);
 317         if (stream == NULL)
 318                 die_errno("Out of memory? fdopen failed");
 319         return stream;
 320 }
 321
 322 int xmkstemp(char *template)
 323 {
 324         int fd;
 325         char origtemplate[PATH_MAX];
 326         strlcpy(origtemplate, template, sizeof(origtemplate));
 327
 328         fd = mkstemp(template);
 329         if (fd < 0) {
 330                 int saved_errno = errno;
 331                 const char *nonrelative_template;
 332
 333                 if (strlen(template) != strlen(origtemplate))
 334                         template = origtemplate;
 335
 336                 nonrelative_template = absolute_path(template);
 337                 errno = saved_errno;
 338                 die_errno("Unable to create temporary file '%s'",
 339                         nonrelative_template);
 340         }
 341         return fd;
 342 }
 343
 344 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 345 int git_mkstemp(char *path, size_t len, const char *template)
 346 {
 347         const char *tmp;
 348         size_t n;
 349
 350         tmp = getenv("TMPDIR");
 351         if (!tmp)
 352                 tmp = "/tmp";
 353         n = snprintf(path, len, "%s/%s", tmp, template);
 354         if (len <= n) {
 355                 errno = ENAMETOOLONG;
 356                 return -1;
 357         }
 358         return mkstemp(path);
 359 }
 360
 361 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 362 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 363 {
 364         const char *tmp;
 365         size_t n;
 366
 367         tmp = getenv("TMPDIR");
 368         if (!tmp)
 369                 tmp = "/tmp";
 370         n = snprintf(path, len, "%s/%s", tmp, template);
 371         if (len <= n) {
 372                 errno = ENAMETOOLONG;
 373                 return -1;
 374         }
 375         return mkstemps(path, suffix_len);
 376 }
 377
 378 /* Adapted from libiberty's mkstemp.c. */
 379
 380 #undef TMP_MAX
 381 #define TMP_MAX 16384
 382
 383 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 384 {
 385         static const char letters[] =
 386                 "abcdefghijklmnopqrstuvwxyz"
 387                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 388                 "0123456789";
 389         static const int num_letters = 62;
 390         uint64_t value;
 391         struct timeval tv;
 392         char *template;
 393         size_t len;
 394         int fd, count;
 395
 396         len = strlen(pattern);
 397
 398         if (len < 6 + suffix_len) {
 399                 errno = EINVAL;
 400                 return -1;
 401         }
 402
 403         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 404                 errno = EINVAL;
 405                 return -1;
 406         }
 407
 408         /*
 409          * Replace pattern's XXXXXX characters with randomness.
 410          * Try TMP_MAX different filenames.
 411          */
 412         gettimeofday(&tv, NULL);
 413         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 414         template = &pattern[len - 6 - suffix_len];
 415         for (count = 0; count < TMP_MAX; ++count) {
 416                 uint64_t v = value;
 417                 /* Fill in the random bits. */
 418                 template[0] = letters[v % num_letters]; v /= num_letters;
 419                 template[1] = letters[v % num_letters]; v /= num_letters;
 420                 template[2] = letters[v % num_letters]; v /= num_letters;
 421                 template[3] = letters[v % num_letters]; v /= num_letters;
 422                 template[4] = letters[v % num_letters]; v /= num_letters;
 423                 template[5] = letters[v % num_letters]; v /= num_letters;
 424
 425                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 426                 if (fd >= 0)
 427                         return fd;
 428                 /*
 429                  * Fatal error (EPERM, ENOSPC etc).
 430                  * It doesn't make sense to loop.
 431                  */
 432                 if (errno != EEXIST)
 433                         break;
 434                 /*
 435                  * This is a random value.  It is only necessary that
 436                  * the next TMP_MAX values generated by adding 7777 to
 437                  * VALUE are different with (module 2^32).
 438                  */
 439                 value += 7777;
 440         }
 441         /* We return the null string if we can't find a unique file name.  */
 442         pattern[0] = '\0';
 443         return -1;
 444 }
 445
 446 int git_mkstemp_mode(char *pattern, int mode)
 447 {
 448         /* mkstemp is just mkstemps with no suffix */
 449         return git_mkstemps_mode(pattern, 0, mode);
 450 }
 451
 452 #ifdef NO_MKSTEMPS
 453 int gitmkstemps(char *pattern, int suffix_len)
 454 {
 455         return git_mkstemps_mode(pattern, suffix_len, 0600);
 456 }
 457 #endif
 458
 459 int xmkstemp_mode(char *template, int mode)
 460 {
 461         int fd;
 462         char origtemplate[PATH_MAX];
 463         strlcpy(origtemplate, template, sizeof(origtemplate));
 464
 465         fd = git_mkstemp_mode(template, mode);
 466         if (fd < 0) {
 467                 int saved_errno = errno;
 468                 const char *nonrelative_template;
 469
 470                 if (!template[0])
 471                         template = origtemplate;
 472
 473                 nonrelative_template = absolute_path(template);
 474                 errno = saved_errno;
 475                 die_errno("Unable to create temporary file '%s'",
 476                         nonrelative_template);
 477         }
 478         return fd;
 479 }
 480
 481 static int warn_if_unremovable(const char *op, const char *file, int rc)
 482 {
 483         int err;
 484         if (!rc || errno == ENOENT)
 485                 return 0;
 486         err = errno;
 487         warning("unable to %s %s: %s", op, file, strerror(errno));
 488         errno = err;
 489         return rc;
 490 }
 491
 492 int unlink_or_msg(const char *file, struct strbuf *err)
 493 {
 494         int rc = unlink(file);
 495
 496         assert(err);
 497
 498         if (!rc || errno == ENOENT)
 499                 return 0;
 500
 501         strbuf_addf(err, "unable to unlink %s: %s",
 502                     file, strerror(errno));
 503         return -1;
 504 }
 505
 506 int unlink_or_warn(const char *file)
 507 {
 508         return warn_if_unremovable("unlink", file, unlink(file));
 509 }
 510
 511 int rmdir_or_warn(const char *file)
 512 {
 513         return warn_if_unremovable("rmdir", file, rmdir(file));
 514 }
 515
 516 int remove_or_warn(unsigned int mode, const char *file)
 517 {
 518         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 519 }
 520
 521 void warn_on_inaccessible(const char *path)
 522 {
 523         warning(_("unable to access '%s': %s"), path, strerror(errno));
 524 }
 525
 526 static int access_error_is_ok(int err, unsigned flag)
 527 {
 528         return err == ENOENT || err == ENOTDIR ||
 529                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 530 }
 531
 532 int access_or_warn(const char *path, int mode, unsigned flag)
 533 {
 534         int ret = access(path, mode);
 535         if (ret && !access_error_is_ok(errno, flag))
 536                 warn_on_inaccessible(path);
 537         return ret;
 538 }
 539
 540 int access_or_die(const char *path, int mode, unsigned flag)
 541 {
 542         int ret = access(path, mode);
 543         if (ret && !access_error_is_ok(errno, flag))
 544                 die_errno(_("unable to access '%s'"), path);
 545         return ret;
 546 }
 547
 548 struct passwd *xgetpwuid_self(void)
 549 {
 550         struct passwd *pw;
 551
 552         errno = 0;
 553         pw = getpwuid(getuid());
 554         if (!pw)
 555                 die(_("unable to look up current user in the passwd file: %s"),
 556                     errno ? strerror(errno) : _("no such user"));
 557         return pw;
 558 }
 559
 560 char *xgetcwd(void)
 561 {
 562         struct strbuf sb = STRBUF_INIT;
 563         if (strbuf_getcwd(&sb))
 564                 die_errno(_("unable to get current working directory"));
 565         return strbuf_detach(&sb, NULL);
 566 }