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  * xread() is the same a read(), but it automatically restarts read()
 135  * operations with a recoverable error (EAGAIN and EINTR). xread()
 136  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 137  */
 138 ssize_t xread(int fd, void *buf, size_t len)
 139 {
 140         ssize_t nr;
 141         while (1) {
 142                 nr = read(fd, buf, len);
 143                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 144                         continue;
 145                 return nr;
 146         }
 147 }
 148
 149 /*
 150  * xwrite() is the same a write(), but it automatically restarts write()
 151  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 152  * GUARANTEE that "len" bytes is written even if the operation is successful.
 153  */
 154 ssize_t xwrite(int fd, const void *buf, size_t len)
 155 {
 156         ssize_t nr;
 157         while (1) {
 158                 nr = write(fd, buf, len);
 159                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 160                         continue;
 161                 return nr;
 162         }
 163 }
 164
 165 ssize_t read_in_full(int fd, void *buf, size_t count)
 166 {
 167         char *p = buf;
 168         ssize_t total = 0;
 169
 170         while (count > 0) {
 171                 ssize_t loaded = xread(fd, p, count);
 172                 if (loaded < 0)
 173                         return -1;
 174                 if (loaded == 0)
 175                         return total;
 176                 count -= loaded;
 177                 p += loaded;
 178                 total += loaded;
 179         }
 180
 181         return total;
 182 }
 183
 184 ssize_t write_in_full(int fd, const void *buf, size_t count)
 185 {
 186         const char *p = buf;
 187         ssize_t total = 0;
 188
 189         while (count > 0) {
 190                 ssize_t written = xwrite(fd, p, count);
 191                 if (written < 0)
 192                         return -1;
 193                 if (!written) {
 194                         errno = ENOSPC;
 195                         return -1;
 196                 }
 197                 count -= written;
 198                 p += written;
 199                 total += written;
 200         }
 201
 202         return total;
 203 }
 204
 205 int xdup(int fd)
 206 {
 207         int ret = dup(fd);
 208         if (ret < 0)
 209                 die_errno("dup failed");
 210         return ret;
 211 }
 212
 213 FILE *xfdopen(int fd, const char *mode)
 214 {
 215         FILE *stream = fdopen(fd, mode);
 216         if (stream == NULL)
 217                 die_errno("Out of memory? fdopen failed");
 218         return stream;
 219 }
 220
 221 int xmkstemp(char *template)
 222 {
 223         int fd;
 224         char origtemplate[PATH_MAX];
 225         strlcpy(origtemplate, template, sizeof(origtemplate));
 226
 227         fd = mkstemp(template);
 228         if (fd < 0) {
 229                 int saved_errno = errno;
 230                 const char *nonrelative_template;
 231
 232                 if (!template[0])
 233                         template = origtemplate;
 234
 235                 nonrelative_template = absolute_path(template);
 236                 errno = saved_errno;
 237                 die_errno("Unable to create temporary file '%s'",
 238                         nonrelative_template);
 239         }
 240         return fd;
 241 }
 242
 243 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 244 int git_mkstemp(char *path, size_t len, const char *template)
 245 {
 246         const char *tmp;
 247         size_t n;
 248
 249         tmp = getenv("TMPDIR");
 250         if (!tmp)
 251                 tmp = "/tmp";
 252         n = snprintf(path, len, "%s/%s", tmp, template);
 253         if (len <= n) {
 254                 errno = ENAMETOOLONG;
 255                 return -1;
 256         }
 257         return mkstemp(path);
 258 }
 259
 260 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 261 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 262 {
 263         const char *tmp;
 264         size_t n;
 265
 266         tmp = getenv("TMPDIR");
 267         if (!tmp)
 268                 tmp = "/tmp";
 269         n = snprintf(path, len, "%s/%s", tmp, template);
 270         if (len <= n) {
 271                 errno = ENAMETOOLONG;
 272                 return -1;
 273         }
 274         return mkstemps(path, suffix_len);
 275 }
 276
 277 /* Adapted from libiberty's mkstemp.c. */
 278
 279 #undef TMP_MAX
 280 #define TMP_MAX 16384
 281
 282 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 283 {
 284         static const char letters[] =
 285                 "abcdefghijklmnopqrstuvwxyz"
 286                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 287                 "0123456789";
 288         static const int num_letters = 62;
 289         uint64_t value;
 290         struct timeval tv;
 291         char *template;
 292         size_t len;
 293         int fd, count;
 294
 295         len = strlen(pattern);
 296
 297         if (len < 6 + suffix_len) {
 298                 errno = EINVAL;
 299                 return -1;
 300         }
 301
 302         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 303                 errno = EINVAL;
 304                 return -1;
 305         }
 306
 307         /*
 308          * Replace pattern's XXXXXX characters with randomness.
 309          * Try TMP_MAX different filenames.
 310          */
 311         gettimeofday(&tv, NULL);
 312         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 313         template = &pattern[len - 6 - suffix_len];
 314         for (count = 0; count < TMP_MAX; ++count) {
 315                 uint64_t v = value;
 316                 /* Fill in the random bits. */
 317                 template[0] = letters[v % num_letters]; v /= num_letters;
 318                 template[1] = letters[v % num_letters]; v /= num_letters;
 319                 template[2] = letters[v % num_letters]; v /= num_letters;
 320                 template[3] = letters[v % num_letters]; v /= num_letters;
 321                 template[4] = letters[v % num_letters]; v /= num_letters;
 322                 template[5] = letters[v % num_letters]; v /= num_letters;
 323
 324                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 325                 if (fd > 0)
 326                         return fd;
 327                 /*
 328                  * Fatal error (EPERM, ENOSPC etc).
 329                  * It doesn't make sense to loop.
 330                  */
 331                 if (errno != EEXIST)
 332                         break;
 333                 /*
 334                  * This is a random value.  It is only necessary that
 335                  * the next TMP_MAX values generated by adding 7777 to
 336                  * VALUE are different with (module 2^32).
 337                  */
 338                 value += 7777;
 339         }
 340         /* We return the null string if we can't find a unique file name.  */
 341         pattern[0] = '\0';
 342         return -1;
 343 }
 344
 345 int git_mkstemp_mode(char *pattern, int mode)
 346 {
 347         /* mkstemp is just mkstemps with no suffix */
 348         return git_mkstemps_mode(pattern, 0, mode);
 349 }
 350
 351 int gitmkstemps(char *pattern, int suffix_len)
 352 {
 353         return git_mkstemps_mode(pattern, suffix_len, 0600);
 354 }
 355
 356 int xmkstemp_mode(char *template, int mode)
 357 {
 358         int fd;
 359         char origtemplate[PATH_MAX];
 360         strlcpy(origtemplate, template, sizeof(origtemplate));
 361
 362         fd = git_mkstemp_mode(template, mode);
 363         if (fd < 0) {
 364                 int saved_errno = errno;
 365                 const char *nonrelative_template;
 366
 367                 if (!template[0])
 368                         template = origtemplate;
 369
 370                 nonrelative_template = absolute_path(template);
 371                 errno = saved_errno;
 372                 die_errno("Unable to create temporary file '%s'",
 373                         nonrelative_template);
 374         }
 375         return fd;
 376 }
 377
 378 static int warn_if_unremovable(const char *op, const char *file, int rc)
 379 {
 380         if (rc < 0) {
 381                 int err = errno;
 382                 if (ENOENT != err) {
 383                         warning("unable to %s %s: %s",
 384                                 op, file, strerror(errno));
 385                         errno = err;
 386                 }
 387         }
 388         return rc;
 389 }
 390
 391 int unlink_or_warn(const char *file)
 392 {
 393         return warn_if_unremovable("unlink", file, unlink(file));
 394 }
 395
 396 int rmdir_or_warn(const char *file)
 397 {
 398         return warn_if_unremovable("rmdir", file, rmdir(file));
 399 }
 400
 401 int remove_or_warn(unsigned int mode, const char *file)
 402 {
 403         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 404 }