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