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 #define MAX_IO_SIZE (8*1024*1024)
 177
 178 /*
 179  * xread() is the same a read(), but it automatically restarts read()
 180  * operations with a recoverable error (EAGAIN and EINTR). xread()
 181  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 182  */
 183 ssize_t xread(int fd, void *buf, size_t len)
 184 {
 185         ssize_t nr;
 186         if (len > MAX_IO_SIZE)
 187             len = MAX_IO_SIZE;
 188         while (1) {
 189                 nr = read(fd, buf, len);
 190                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 191                         continue;
 192                 return nr;
 193         }
 194 }
 195
 196 /*
 197  * xwrite() is the same a write(), but it automatically restarts write()
 198  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 199  * GUARANTEE that "len" bytes is written even if the operation is successful.
 200  */
 201 ssize_t xwrite(int fd, const void *buf, size_t len)
 202 {
 203         ssize_t nr;
 204         if (len > MAX_IO_SIZE)
 205             len = MAX_IO_SIZE;
 206         while (1) {
 207                 nr = write(fd, buf, len);
 208                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 209                         continue;
 210                 return nr;
 211         }
 212 }
 213
 214 /*
 215  * xpread() is the same as pread(), but it automatically restarts pread()
 216  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 217  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 218  */
 219 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 220 {
 221         ssize_t nr;
 222         if (len > MAX_IO_SIZE)
 223                 len = MAX_IO_SIZE;
 224         while (1) {
 225                 nr = pread(fd, buf, len, offset);
 226                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 227                         continue;
 228                 return nr;
 229         }
 230 }
 231
 232 ssize_t read_in_full(int fd, void *buf, size_t count)
 233 {
 234         char *p = buf;
 235         ssize_t total = 0;
 236
 237         while (count > 0) {
 238                 ssize_t loaded = xread(fd, p, count);
 239                 if (loaded < 0)
 240                         return -1;
 241                 if (loaded == 0)
 242                         return total;
 243                 count -= loaded;
 244                 p += loaded;
 245                 total += loaded;
 246         }
 247
 248         return total;
 249 }
 250
 251 ssize_t write_in_full(int fd, const void *buf, size_t count)
 252 {
 253         const char *p = buf;
 254         ssize_t total = 0;
 255
 256         while (count > 0) {
 257                 ssize_t written = xwrite(fd, p, count);
 258                 if (written < 0)
 259                         return -1;
 260                 if (!written) {
 261                         errno = ENOSPC;
 262                         return -1;
 263                 }
 264                 count -= written;
 265                 p += written;
 266                 total += written;
 267         }
 268
 269         return total;
 270 }
 271
 272 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 273 {
 274         char *p = buf;
 275         ssize_t total = 0;
 276
 277         while (count > 0) {
 278                 ssize_t loaded = xpread(fd, p, count, offset);
 279                 if (loaded < 0)
 280                         return -1;
 281                 if (loaded == 0)
 282                         return total;
 283                 count -= loaded;
 284                 p += loaded;
 285                 total += loaded;
 286                 offset += loaded;
 287         }
 288
 289         return total;
 290 }
 291
 292 int xdup(int fd)
 293 {
 294         int ret = dup(fd);
 295         if (ret < 0)
 296                 die_errno("dup failed");
 297         return ret;
 298 }
 299
 300 FILE *xfdopen(int fd, const char *mode)
 301 {
 302         FILE *stream = fdopen(fd, mode);
 303         if (stream == NULL)
 304                 die_errno("Out of memory? fdopen failed");
 305         return stream;
 306 }
 307
 308 int xmkstemp(char *template)
 309 {
 310         int fd;
 311         char origtemplate[PATH_MAX];
 312         strlcpy(origtemplate, template, sizeof(origtemplate));
 313
 314         fd = mkstemp(template);
 315         if (fd < 0) {
 316                 int saved_errno = errno;
 317                 const char *nonrelative_template;
 318
 319                 if (strlen(template) != strlen(origtemplate))
 320                         template = origtemplate;
 321
 322                 nonrelative_template = absolute_path(template);
 323                 errno = saved_errno;
 324                 die_errno("Unable to create temporary file '%s'",
 325                         nonrelative_template);
 326         }
 327         return fd;
 328 }
 329
 330 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 331 int git_mkstemp(char *path, size_t len, const char *template)
 332 {
 333         const char *tmp;
 334         size_t n;
 335
 336         tmp = getenv("TMPDIR");
 337         if (!tmp)
 338                 tmp = "/tmp";
 339         n = snprintf(path, len, "%s/%s", tmp, template);
 340         if (len <= n) {
 341                 errno = ENAMETOOLONG;
 342                 return -1;
 343         }
 344         return mkstemp(path);
 345 }
 346
 347 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 348 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 349 {
 350         const char *tmp;
 351         size_t n;
 352
 353         tmp = getenv("TMPDIR");
 354         if (!tmp)
 355                 tmp = "/tmp";
 356         n = snprintf(path, len, "%s/%s", tmp, template);
 357         if (len <= n) {
 358                 errno = ENAMETOOLONG;
 359                 return -1;
 360         }
 361         return mkstemps(path, suffix_len);
 362 }
 363
 364 /* Adapted from libiberty's mkstemp.c. */
 365
 366 #undef TMP_MAX
 367 #define TMP_MAX 16384
 368
 369 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 370 {
 371         static const char letters[] =
 372                 "abcdefghijklmnopqrstuvwxyz"
 373                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 374                 "0123456789";
 375         static const int num_letters = 62;
 376         uint64_t value;
 377         struct timeval tv;
 378         char *template;
 379         size_t len;
 380         int fd, count;
 381
 382         len = strlen(pattern);
 383
 384         if (len < 6 + suffix_len) {
 385                 errno = EINVAL;
 386                 return -1;
 387         }
 388
 389         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 390                 errno = EINVAL;
 391                 return -1;
 392         }
 393
 394         /*
 395          * Replace pattern's XXXXXX characters with randomness.
 396          * Try TMP_MAX different filenames.
 397          */
 398         gettimeofday(&tv, NULL);
 399         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 400         template = &pattern[len - 6 - suffix_len];
 401         for (count = 0; count < TMP_MAX; ++count) {
 402                 uint64_t v = value;
 403                 /* Fill in the random bits. */
 404                 template[0] = letters[v % num_letters]; v /= num_letters;
 405                 template[1] = letters[v % num_letters]; v /= num_letters;
 406                 template[2] = letters[v % num_letters]; v /= num_letters;
 407                 template[3] = letters[v % num_letters]; v /= num_letters;
 408                 template[4] = letters[v % num_letters]; v /= num_letters;
 409                 template[5] = letters[v % num_letters]; v /= num_letters;
 410
 411                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 412                 if (fd >= 0)
 413                         return fd;
 414                 /*
 415                  * Fatal error (EPERM, ENOSPC etc).
 416                  * It doesn't make sense to loop.
 417                  */
 418                 if (errno != EEXIST)
 419                         break;
 420                 /*
 421                  * This is a random value.  It is only necessary that
 422                  * the next TMP_MAX values generated by adding 7777 to
 423                  * VALUE are different with (module 2^32).
 424                  */
 425                 value += 7777;
 426         }
 427         /* We return the null string if we can't find a unique file name.  */
 428         pattern[0] = '\0';
 429         return -1;
 430 }
 431
 432 int git_mkstemp_mode(char *pattern, int mode)
 433 {
 434         /* mkstemp is just mkstemps with no suffix */
 435         return git_mkstemps_mode(pattern, 0, mode);
 436 }
 437
 438 #ifdef NO_MKSTEMPS
 439 int gitmkstemps(char *pattern, int suffix_len)
 440 {
 441         return git_mkstemps_mode(pattern, suffix_len, 0600);
 442 }
 443 #endif
 444
 445 int xmkstemp_mode(char *template, int mode)
 446 {
 447         int fd;
 448         char origtemplate[PATH_MAX];
 449         strlcpy(origtemplate, template, sizeof(origtemplate));
 450
 451         fd = git_mkstemp_mode(template, mode);
 452         if (fd < 0) {
 453                 int saved_errno = errno;
 454                 const char *nonrelative_template;
 455
 456                 if (!template[0])
 457                         template = origtemplate;
 458
 459                 nonrelative_template = absolute_path(template);
 460                 errno = saved_errno;
 461                 die_errno("Unable to create temporary file '%s'",
 462                         nonrelative_template);
 463         }
 464         return fd;
 465 }
 466
 467 static int warn_if_unremovable(const char *op, const char *file, int rc)
 468 {
 469         int err;
 470         if (!rc || errno == ENOENT)
 471                 return 0;
 472         err = errno;
 473         warning("unable to %s %s: %s", op, file, strerror(errno));
 474         errno = err;
 475         return rc;
 476 }
 477
 478 int unlink_or_msg(const char *file, struct strbuf *err)
 479 {
 480         int rc = unlink(file);
 481
 482         assert(err);
 483
 484         if (!rc || errno == ENOENT)
 485                 return 0;
 486
 487         strbuf_addf(err, "unable to unlink %s: %s",
 488                     file, strerror(errno));
 489         return -1;
 490 }
 491
 492 int unlink_or_warn(const char *file)
 493 {
 494         return warn_if_unremovable("unlink", file, unlink(file));
 495 }
 496
 497 int rmdir_or_warn(const char *file)
 498 {
 499         return warn_if_unremovable("rmdir", file, rmdir(file));
 500 }
 501
 502 int remove_or_warn(unsigned int mode, const char *file)
 503 {
 504         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 505 }
 506
 507 void warn_on_inaccessible(const char *path)
 508 {
 509         warning(_("unable to access '%s': %s"), path, strerror(errno));
 510 }
 511
 512 static int access_error_is_ok(int err, unsigned flag)
 513 {
 514         return err == ENOENT || err == ENOTDIR ||
 515                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 516 }
 517
 518 int access_or_warn(const char *path, int mode, unsigned flag)
 519 {
 520         int ret = access(path, mode);
 521         if (ret && !access_error_is_ok(errno, flag))
 522                 warn_on_inaccessible(path);
 523         return ret;
 524 }
 525
 526 int access_or_die(const char *path, int mode, unsigned flag)
 527 {
 528         int ret = access(path, mode);
 529         if (ret && !access_error_is_ok(errno, flag))
 530                 die_errno(_("unable to access '%s'"), path);
 531         return ret;
 532 }
 533
 534 struct passwd *xgetpwuid_self(void)
 535 {
 536         struct passwd *pw;
 537
 538         errno = 0;
 539         pw = getpwuid(getuid());
 540         if (!pw)
 541                 die(_("unable to look up current user in the passwd file: %s"),
 542                     errno ? strerror(errno) : _("no such user"));
 543         return pw;
 544 }
 545
 546 char *xgetcwd(void)
 547 {
 548         struct strbuf sb = STRBUF_INIT;
 549         if (strbuf_getcwd(&sb))
 550                 die_errno(_("unable to get current working directory"));
 551         return strbuf_detach(&sb, NULL);
 552 }