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 absense of bugs, large chunks can result in bad latencies when
 137  * you decide to kill the process.
 138  *
 139  * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
 140  * that is smaller than that, clip it to SSIZE_MAX, as a call to
 141  * read(2) or write(2) larger than that is allowed to fail.  As the last
 142  * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
 143  * to override this, if the definition of SSIZE_MAX given by the platform
 144  * is broken.
 145  */
 146 #ifndef MAX_IO_SIZE
 147 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
 148 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
 149 #  define MAX_IO_SIZE SSIZE_MAX
 150 # else
 151 #  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
 152 # endif
 153 #endif
 154
 155 /*
 156  * xread() is the same a read(), but it automatically restarts read()
 157  * operations with a recoverable error (EAGAIN and EINTR). xread()
 158  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 159  */
 160 ssize_t xread(int fd, void *buf, size_t len)
 161 {
 162         ssize_t nr;
 163         if (len > MAX_IO_SIZE)
 164             len = MAX_IO_SIZE;
 165         while (1) {
 166                 nr = read(fd, buf, len);
 167                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 168                         continue;
 169                 return nr;
 170         }
 171 }
 172
 173 /*
 174  * xwrite() is the same a write(), but it automatically restarts write()
 175  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 176  * GUARANTEE that "len" bytes is written even if the operation is successful.
 177  */
 178 ssize_t xwrite(int fd, const void *buf, size_t len)
 179 {
 180         ssize_t nr;
 181         if (len > MAX_IO_SIZE)
 182             len = MAX_IO_SIZE;
 183         while (1) {
 184                 nr = write(fd, buf, len);
 185                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 186                         continue;
 187                 return nr;
 188         }
 189 }
 190
 191 ssize_t read_in_full(int fd, void *buf, size_t count)
 192 {
 193         char *p = buf;
 194         ssize_t total = 0;
 195
 196         while (count > 0) {
 197                 ssize_t loaded = xread(fd, p, count);
 198                 if (loaded < 0)
 199                         return -1;
 200                 if (loaded == 0)
 201                         return total;
 202                 count -= loaded;
 203                 p += loaded;
 204                 total += loaded;
 205         }
 206
 207         return total;
 208 }
 209
 210 ssize_t write_in_full(int fd, const void *buf, size_t count)
 211 {
 212         const char *p = buf;
 213         ssize_t total = 0;
 214
 215         while (count > 0) {
 216                 ssize_t written = xwrite(fd, p, count);
 217                 if (written < 0)
 218                         return -1;
 219                 if (!written) {
 220                         errno = ENOSPC;
 221                         return -1;
 222                 }
 223                 count -= written;
 224                 p += written;
 225                 total += written;
 226         }
 227
 228         return total;
 229 }
 230
 231 int xdup(int fd)
 232 {
 233         int ret = dup(fd);
 234         if (ret < 0)
 235                 die_errno("dup failed");
 236         return ret;
 237 }
 238
 239 FILE *xfdopen(int fd, const char *mode)
 240 {
 241         FILE *stream = fdopen(fd, mode);
 242         if (stream == NULL)
 243                 die_errno("Out of memory? fdopen failed");
 244         return stream;
 245 }
 246
 247 int xmkstemp(char *template)
 248 {
 249         int fd;
 250         char origtemplate[PATH_MAX];
 251         strlcpy(origtemplate, template, sizeof(origtemplate));
 252
 253         fd = mkstemp(template);
 254         if (fd < 0) {
 255                 int saved_errno = errno;
 256                 const char *nonrelative_template;
 257
 258                 if (strlen(template) != strlen(origtemplate))
 259                         template = origtemplate;
 260
 261                 nonrelative_template = absolute_path(template);
 262                 errno = saved_errno;
 263                 die_errno("Unable to create temporary file '%s'",
 264                         nonrelative_template);
 265         }
 266         return fd;
 267 }
 268
 269 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 270 int git_mkstemp(char *path, size_t len, const char *template)
 271 {
 272         const char *tmp;
 273         size_t n;
 274
 275         tmp = getenv("TMPDIR");
 276         if (!tmp)
 277                 tmp = "/tmp";
 278         n = snprintf(path, len, "%s/%s", tmp, template);
 279         if (len <= n) {
 280                 errno = ENAMETOOLONG;
 281                 return -1;
 282         }
 283         return mkstemp(path);
 284 }
 285
 286 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 287 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 288 {
 289         const char *tmp;
 290         size_t n;
 291
 292         tmp = getenv("TMPDIR");
 293         if (!tmp)
 294                 tmp = "/tmp";
 295         n = snprintf(path, len, "%s/%s", tmp, template);
 296         if (len <= n) {
 297                 errno = ENAMETOOLONG;
 298                 return -1;
 299         }
 300         return mkstemps(path, suffix_len);
 301 }
 302
 303 /* Adapted from libiberty's mkstemp.c. */
 304
 305 #undef TMP_MAX
 306 #define TMP_MAX 16384
 307
 308 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 309 {
 310         static const char letters[] =
 311                 "abcdefghijklmnopqrstuvwxyz"
 312                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 313                 "0123456789";
 314         static const int num_letters = 62;
 315         uint64_t value;
 316         struct timeval tv;
 317         char *template;
 318         size_t len;
 319         int fd, count;
 320
 321         len = strlen(pattern);
 322
 323         if (len < 6 + suffix_len) {
 324                 errno = EINVAL;
 325                 return -1;
 326         }
 327
 328         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 329                 errno = EINVAL;
 330                 return -1;
 331         }
 332
 333         /*
 334          * Replace pattern's XXXXXX characters with randomness.
 335          * Try TMP_MAX different filenames.
 336          */
 337         gettimeofday(&tv, NULL);
 338         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 339         template = &pattern[len - 6 - suffix_len];
 340         for (count = 0; count < TMP_MAX; ++count) {
 341                 uint64_t v = value;
 342                 /* Fill in the random bits. */
 343                 template[0] = letters[v % num_letters]; v /= num_letters;
 344                 template[1] = letters[v % num_letters]; v /= num_letters;
 345                 template[2] = letters[v % num_letters]; v /= num_letters;
 346                 template[3] = letters[v % num_letters]; v /= num_letters;
 347                 template[4] = letters[v % num_letters]; v /= num_letters;
 348                 template[5] = letters[v % num_letters]; v /= num_letters;
 349
 350                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 351                 if (fd >= 0)
 352                         return fd;
 353                 /*
 354                  * Fatal error (EPERM, ENOSPC etc).
 355                  * It doesn't make sense to loop.
 356                  */
 357                 if (errno != EEXIST)
 358                         break;
 359                 /*
 360                  * This is a random value.  It is only necessary that
 361                  * the next TMP_MAX values generated by adding 7777 to
 362                  * VALUE are different with (module 2^32).
 363                  */
 364                 value += 7777;
 365         }
 366         /* We return the null string if we can't find a unique file name.  */
 367         pattern[0] = '\0';
 368         return -1;
 369 }
 370
 371 int git_mkstemp_mode(char *pattern, int mode)
 372 {
 373         /* mkstemp is just mkstemps with no suffix */
 374         return git_mkstemps_mode(pattern, 0, mode);
 375 }
 376
 377 int gitmkstemps(char *pattern, int suffix_len)
 378 {
 379         return git_mkstemps_mode(pattern, suffix_len, 0600);
 380 }
 381
 382 int xmkstemp_mode(char *template, int mode)
 383 {
 384         int fd;
 385         char origtemplate[PATH_MAX];
 386         strlcpy(origtemplate, template, sizeof(origtemplate));
 387
 388         fd = git_mkstemp_mode(template, mode);
 389         if (fd < 0) {
 390                 int saved_errno = errno;
 391                 const char *nonrelative_template;
 392
 393                 if (!template[0])
 394                         template = origtemplate;
 395
 396                 nonrelative_template = absolute_path(template);
 397                 errno = saved_errno;
 398                 die_errno("Unable to create temporary file '%s'",
 399                         nonrelative_template);
 400         }
 401         return fd;
 402 }
 403
 404 static int warn_if_unremovable(const char *op, const char *file, int rc)
 405 {
 406         if (rc < 0) {
 407                 int err = errno;
 408                 if (ENOENT != err) {
 409                         warning("unable to %s %s: %s",
 410                                 op, file, strerror(errno));
 411                         errno = err;
 412                 }
 413         }
 414         return rc;
 415 }
 416
 417 int unlink_or_warn(const char *file)
 418 {
 419         return warn_if_unremovable("unlink", file, unlink(file));
 420 }
 421
 422 int rmdir_or_warn(const char *file)
 423 {
 424         return warn_if_unremovable("rmdir", file, rmdir(file));
 425 }
 426
 427 int remove_or_warn(unsigned int mode, const char *file)
 428 {
 429         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 430 }
 431
 432 void warn_on_inaccessible(const char *path)
 433 {
 434         warning(_("unable to access '%s': %s"), path, strerror(errno));
 435 }
 436
 437 static int access_error_is_ok(int err, unsigned flag)
 438 {
 439         return err == ENOENT || err == ENOTDIR ||
 440                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 441 }
 442
 443 int access_or_warn(const char *path, int mode, unsigned flag)
 444 {
 445         int ret = access(path, mode);
 446         if (ret && !access_error_is_ok(errno, flag))
 447                 warn_on_inaccessible(path);
 448         return ret;
 449 }
 450
 451 int access_or_die(const char *path, int mode, unsigned flag)
 452 {
 453         int ret = access(path, mode);
 454         if (ret && !access_error_is_ok(errno, flag))
 455                 die_errno(_("unable to access '%s'"), path);
 456         return ret;
 457 }
 458
 459 struct passwd *xgetpwuid_self(void)
 460 {
 461         struct passwd *pw;
 462
 463         errno = 0;
 464         pw = getpwuid(getuid());
 465         if (!pw)
 466                 die(_("unable to look up current user in the passwd file: %s"),
 467                     errno ? strerror(errno) : _("no such user"));
 468         return pw;
 469 }