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