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 int limit = -1;
  15         if (limit == -1) {
  16                 const char *env = getenv("GIT_ALLOC_LIMIT");
  17                 limit = env ? atoi(env) * 1024 : 0;
  18         }
  19         if (limit && size > limit) {
  20                 if (gentle) {
  21                         error("attempting to allocate %"PRIuMAX" over limit %d",
  22                               (intmax_t)size, limit);
  23                         return -1;
  24                 } else
  25                         die("attempting to allocate %"PRIuMAX" over limit %d",
  26                             (intmax_t)size, limit);
  27         }
  28         return 0;
  29 }
  30
  31 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
  32 {
  33         try_to_free_t old = try_to_free_routine;
  34         if (!routine)
  35                 routine = do_nothing;
  36         try_to_free_routine = routine;
  37         return old;
  38 }
  39
  40 char *xstrdup(const char *str)
  41 {
  42         char *ret = strdup(str);
  43         if (!ret) {
  44                 try_to_free_routine(strlen(str) + 1);
  45                 ret = strdup(str);
  46                 if (!ret)
  47                         die("Out of memory, strdup failed");
  48         }
  49         return ret;
  50 }
  51
  52 static void *do_xmalloc(size_t size, int gentle)
  53 {
  54         void *ret;
  55
  56         if (memory_limit_check(size, gentle))
  57                 return NULL;
  58         ret = malloc(size);
  59         if (!ret && !size)
  60                 ret = malloc(1);
  61         if (!ret) {
  62                 try_to_free_routine(size);
  63                 ret = malloc(size);
  64                 if (!ret && !size)
  65                         ret = malloc(1);
  66                 if (!ret) {
  67                         if (!gentle)
  68                                 die("Out of memory, malloc failed (tried to allocate %lu bytes)",
  69                                     (unsigned long)size);
  70                         else {
  71                                 error("Out of memory, malloc failed (tried to allocate %lu bytes)",
  72                                       (unsigned long)size);
  73                                 return NULL;
  74                         }
  75                 }
  76         }
  77 #ifdef XMALLOC_POISON
  78         memset(ret, 0xA5, size);
  79 #endif
  80         return ret;
  81 }
  82
  83 void *xmalloc(size_t size)
  84 {
  85         return do_xmalloc(size, 0);
  86 }
  87
  88 static void *do_xmallocz(size_t size, int gentle)
  89 {
  90         void *ret;
  91         if (unsigned_add_overflows(size, 1)) {
  92                 if (gentle) {
  93                         error("Data too large to fit into virtual memory space.");
  94                         return NULL;
  95                 } else
  96                         die("Data too large to fit into virtual memory space.");
  97         }
  98         ret = do_xmalloc(size + 1, gentle);
  99         if (ret)
 100                 ((char*)ret)[size] = 0;
 101         return ret;
 102 }
 103
 104 void *xmallocz(size_t size)
 105 {
 106         return do_xmallocz(size, 0);
 107 }
 108
 109 void *xmallocz_gently(size_t size)
 110 {
 111         return do_xmallocz(size, 1);
 112 }
 113
 114 /*
 115  * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
 116  * "data" to the allocated memory, zero terminates the allocated memory,
 117  * and returns a pointer to the allocated memory. If the allocation fails,
 118  * the program dies.
 119  */
 120 void *xmemdupz(const void *data, size_t len)
 121 {
 122         return memcpy(xmallocz(len), data, len);
 123 }
 124
 125 char *xstrndup(const char *str, size_t len)
 126 {
 127         char *p = memchr(str, '\0', len);
 128         return xmemdupz(str, p ? p - str : len);
 129 }
 130
 131 void *xrealloc(void *ptr, size_t size)
 132 {
 133         void *ret;
 134
 135         memory_limit_check(size, 0);
 136         ret = realloc(ptr, size);
 137         if (!ret && !size)
 138                 ret = realloc(ptr, 1);
 139         if (!ret) {
 140                 try_to_free_routine(size);
 141                 ret = realloc(ptr, size);
 142                 if (!ret && !size)
 143                         ret = realloc(ptr, 1);
 144                 if (!ret)
 145                         die("Out of memory, realloc failed");
 146         }
 147         return ret;
 148 }
 149
 150 void *xcalloc(size_t nmemb, size_t size)
 151 {
 152         void *ret;
 153
 154         memory_limit_check(size * nmemb, 0);
 155         ret = calloc(nmemb, size);
 156         if (!ret && (!nmemb || !size))
 157                 ret = calloc(1, 1);
 158         if (!ret) {
 159                 try_to_free_routine(nmemb * size);
 160                 ret = calloc(nmemb, size);
 161                 if (!ret && (!nmemb || !size))
 162                         ret = calloc(1, 1);
 163                 if (!ret)
 164                         die("Out of memory, calloc failed");
 165         }
 166         return ret;
 167 }
 168
 169 /*
 170  * Limit size of IO chunks, because huge chunks only cause pain.  OS X
 171  * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
 172  * the absence of bugs, large chunks can result in bad latencies when
 173  * you decide to kill the process.
 174  */
 175 #define MAX_IO_SIZE (8*1024*1024)
 176
 177 /*
 178  * xread() is the same a read(), but it automatically restarts read()
 179  * operations with a recoverable error (EAGAIN and EINTR). xread()
 180  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 181  */
 182 ssize_t xread(int fd, void *buf, size_t len)
 183 {
 184         ssize_t nr;
 185         if (len > MAX_IO_SIZE)
 186             len = MAX_IO_SIZE;
 187         while (1) {
 188                 nr = read(fd, buf, len);
 189                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 190                         continue;
 191                 return nr;
 192         }
 193 }
 194
 195 /*
 196  * xwrite() is the same a write(), but it automatically restarts write()
 197  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 198  * GUARANTEE that "len" bytes is written even if the operation is successful.
 199  */
 200 ssize_t xwrite(int fd, const void *buf, size_t len)
 201 {
 202         ssize_t nr;
 203         if (len > MAX_IO_SIZE)
 204             len = MAX_IO_SIZE;
 205         while (1) {
 206                 nr = write(fd, buf, len);
 207                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 208                         continue;
 209                 return nr;
 210         }
 211 }
 212
 213 /*
 214  * xpread() is the same as pread(), but it automatically restarts pread()
 215  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 216  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 217  */
 218 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 219 {
 220         ssize_t nr;
 221         if (len > MAX_IO_SIZE)
 222                 len = MAX_IO_SIZE;
 223         while (1) {
 224                 nr = pread(fd, buf, len, offset);
 225                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 226                         continue;
 227                 return nr;
 228         }
 229 }
 230
 231 ssize_t read_in_full(int fd, void *buf, size_t count)
 232 {
 233         char *p = buf;
 234         ssize_t total = 0;
 235
 236         while (count > 0) {
 237                 ssize_t loaded = xread(fd, p, count);
 238                 if (loaded < 0)
 239                         return -1;
 240                 if (loaded == 0)
 241                         return total;
 242                 count -= loaded;
 243                 p += loaded;
 244                 total += loaded;
 245         }
 246
 247         return total;
 248 }
 249
 250 ssize_t write_in_full(int fd, const void *buf, size_t count)
 251 {
 252         const char *p = buf;
 253         ssize_t total = 0;
 254
 255         while (count > 0) {
 256                 ssize_t written = xwrite(fd, p, count);
 257                 if (written < 0)
 258                         return -1;
 259                 if (!written) {
 260                         errno = ENOSPC;
 261                         return -1;
 262                 }
 263                 count -= written;
 264                 p += written;
 265                 total += written;
 266         }
 267
 268         return total;
 269 }
 270
 271 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 272 {
 273         char *p = buf;
 274         ssize_t total = 0;
 275
 276         while (count > 0) {
 277                 ssize_t loaded = xpread(fd, p, count, offset);
 278                 if (loaded < 0)
 279                         return -1;
 280                 if (loaded == 0)
 281                         return total;
 282                 count -= loaded;
 283                 p += loaded;
 284                 total += loaded;
 285                 offset += loaded;
 286         }
 287
 288         return total;
 289 }
 290
 291 int xdup(int fd)
 292 {
 293         int ret = dup(fd);
 294         if (ret < 0)
 295                 die_errno("dup failed");
 296         return ret;
 297 }
 298
 299 FILE *xfdopen(int fd, const char *mode)
 300 {
 301         FILE *stream = fdopen(fd, mode);
 302         if (stream == NULL)
 303                 die_errno("Out of memory? fdopen failed");
 304         return stream;
 305 }
 306
 307 int xmkstemp(char *template)
 308 {
 309         int fd;
 310         char origtemplate[PATH_MAX];
 311         strlcpy(origtemplate, template, sizeof(origtemplate));
 312
 313         fd = mkstemp(template);
 314         if (fd < 0) {
 315                 int saved_errno = errno;
 316                 const char *nonrelative_template;
 317
 318                 if (strlen(template) != strlen(origtemplate))
 319                         template = origtemplate;
 320
 321                 nonrelative_template = absolute_path(template);
 322                 errno = saved_errno;
 323                 die_errno("Unable to create temporary file '%s'",
 324                         nonrelative_template);
 325         }
 326         return fd;
 327 }
 328
 329 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 330 int git_mkstemp(char *path, size_t len, const char *template)
 331 {
 332         const char *tmp;
 333         size_t n;
 334
 335         tmp = getenv("TMPDIR");
 336         if (!tmp)
 337                 tmp = "/tmp";
 338         n = snprintf(path, len, "%s/%s", tmp, template);
 339         if (len <= n) {
 340                 errno = ENAMETOOLONG;
 341                 return -1;
 342         }
 343         return mkstemp(path);
 344 }
 345
 346 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 347 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 348 {
 349         const char *tmp;
 350         size_t n;
 351
 352         tmp = getenv("TMPDIR");
 353         if (!tmp)
 354                 tmp = "/tmp";
 355         n = snprintf(path, len, "%s/%s", tmp, template);
 356         if (len <= n) {
 357                 errno = ENAMETOOLONG;
 358                 return -1;
 359         }
 360         return mkstemps(path, suffix_len);
 361 }
 362
 363 /* Adapted from libiberty's mkstemp.c. */
 364
 365 #undef TMP_MAX
 366 #define TMP_MAX 16384
 367
 368 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 369 {
 370         static const char letters[] =
 371                 "abcdefghijklmnopqrstuvwxyz"
 372                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 373                 "0123456789";
 374         static const int num_letters = 62;
 375         uint64_t value;
 376         struct timeval tv;
 377         char *template;
 378         size_t len;
 379         int fd, count;
 380
 381         len = strlen(pattern);
 382
 383         if (len < 6 + suffix_len) {
 384                 errno = EINVAL;
 385                 return -1;
 386         }
 387
 388         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 389                 errno = EINVAL;
 390                 return -1;
 391         }
 392
 393         /*
 394          * Replace pattern's XXXXXX characters with randomness.
 395          * Try TMP_MAX different filenames.
 396          */
 397         gettimeofday(&tv, NULL);
 398         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 399         template = &pattern[len - 6 - suffix_len];
 400         for (count = 0; count < TMP_MAX; ++count) {
 401                 uint64_t v = value;
 402                 /* Fill in the random bits. */
 403                 template[0] = letters[v % num_letters]; v /= num_letters;
 404                 template[1] = letters[v % num_letters]; v /= num_letters;
 405                 template[2] = letters[v % num_letters]; v /= num_letters;
 406                 template[3] = letters[v % num_letters]; v /= num_letters;
 407                 template[4] = letters[v % num_letters]; v /= num_letters;
 408                 template[5] = letters[v % num_letters]; v /= num_letters;
 409
 410                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 411                 if (fd >= 0)
 412                         return fd;
 413                 /*
 414                  * Fatal error (EPERM, ENOSPC etc).
 415                  * It doesn't make sense to loop.
 416                  */
 417                 if (errno != EEXIST)
 418                         break;
 419                 /*
 420                  * This is a random value.  It is only necessary that
 421                  * the next TMP_MAX values generated by adding 7777 to
 422                  * VALUE are different with (module 2^32).
 423                  */
 424                 value += 7777;
 425         }
 426         /* We return the null string if we can't find a unique file name.  */
 427         pattern[0] = '\0';
 428         return -1;
 429 }
 430
 431 int git_mkstemp_mode(char *pattern, int mode)
 432 {
 433         /* mkstemp is just mkstemps with no suffix */
 434         return git_mkstemps_mode(pattern, 0, mode);
 435 }
 436
 437 #ifdef NO_MKSTEMPS
 438 int gitmkstemps(char *pattern, int suffix_len)
 439 {
 440         return git_mkstemps_mode(pattern, suffix_len, 0600);
 441 }
 442 #endif
 443
 444 int xmkstemp_mode(char *template, int mode)
 445 {
 446         int fd;
 447         char origtemplate[PATH_MAX];
 448         strlcpy(origtemplate, template, sizeof(origtemplate));
 449
 450         fd = git_mkstemp_mode(template, mode);
 451         if (fd < 0) {
 452                 int saved_errno = errno;
 453                 const char *nonrelative_template;
 454
 455                 if (!template[0])
 456                         template = origtemplate;
 457
 458                 nonrelative_template = absolute_path(template);
 459                 errno = saved_errno;
 460                 die_errno("Unable to create temporary file '%s'",
 461                         nonrelative_template);
 462         }
 463         return fd;
 464 }
 465
 466 static int warn_if_unremovable(const char *op, const char *file, int rc)
 467 {
 468         if (rc < 0) {
 469                 int err = errno;
 470                 if (ENOENT != err) {
 471                         warning("unable to %s %s: %s",
 472                                 op, file, strerror(errno));
 473                         errno = err;
 474                 }
 475         }
 476         return rc;
 477 }
 478
 479 int unlink_or_warn(const char *file)
 480 {
 481         return warn_if_unremovable("unlink", file, unlink(file));
 482 }
 483
 484 int rmdir_or_warn(const char *file)
 485 {
 486         return warn_if_unremovable("rmdir", file, rmdir(file));
 487 }
 488
 489 int remove_or_warn(unsigned int mode, const char *file)
 490 {
 491         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 492 }
 493
 494 void warn_on_inaccessible(const char *path)
 495 {
 496         warning(_("unable to access '%s': %s"), path, strerror(errno));
 497 }
 498
 499 static int access_error_is_ok(int err, unsigned flag)
 500 {
 501         return err == ENOENT || err == ENOTDIR ||
 502                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 503 }
 504
 505 int access_or_warn(const char *path, int mode, unsigned flag)
 506 {
 507         int ret = access(path, mode);
 508         if (ret && !access_error_is_ok(errno, flag))
 509                 warn_on_inaccessible(path);
 510         return ret;
 511 }
 512
 513 int access_or_die(const char *path, int mode, unsigned flag)
 514 {
 515         int ret = access(path, mode);
 516         if (ret && !access_error_is_ok(errno, flag))
 517                 die_errno(_("unable to access '%s'"), path);
 518         return ret;
 519 }
 520
 521 struct passwd *xgetpwuid_self(void)
 522 {
 523         struct passwd *pw;
 524
 525         errno = 0;
 526         pw = getpwuid(getuid());
 527         if (!pw)
 528                 die(_("unable to look up current user in the passwd file: %s"),
 529                     errno ? strerror(errno) : _("no such user"));
 530         return pw;
 531 }
 532
 533 char *xgetcwd(void)
 534 {
 535         struct strbuf sb = STRBUF_INIT;
 536         if (strbuf_getcwd(&sb))
 537                 die_errno(_("unable to get current working directory"));
 538         return strbuf_detach(&sb, NULL);
 539 }