wrapper.c

   1 /*
   2  * Various trivial helper wrappers around standard functions
   3  */
   4 #include "cache.h"
   5
   6 static void try_to_free_builtin(size_t size)
   7 {
   8         release_pack_memory(size, -1);
   9 }
  10
  11 static void (*try_to_free_routine)(size_t size) = try_to_free_builtin;
  12
  13 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
  14 {
  15         try_to_free_t old = try_to_free_routine;
  16         try_to_free_routine = routine;
  17         return old;
  18 }
  19
  20 char *xstrdup(const char *str)
  21 {
  22         char *ret = strdup(str);
  23         if (!ret) {
  24                 try_to_free_routine(strlen(str) + 1);
  25                 ret = strdup(str);
  26                 if (!ret)
  27                         die("Out of memory, strdup failed");
  28         }
  29         return ret;
  30 }
  31
  32 void *xmalloc(size_t size)
  33 {
  34         void *ret = malloc(size);
  35         if (!ret && !size)
  36                 ret = malloc(1);
  37         if (!ret) {
  38                 try_to_free_routine(size);
  39                 ret = malloc(size);
  40                 if (!ret && !size)
  41                         ret = malloc(1);
  42                 if (!ret)
  43                         die("Out of memory, malloc failed (tried to allocate %lu bytes)",
  44                             (unsigned long)size);
  45         }
  46 #ifdef XMALLOC_POISON
  47         memset(ret, 0xA5, size);
  48 #endif
  49         return ret;
  50 }
  51
  52 void *xmallocz(size_t size)
  53 {
  54         void *ret;
  55         if (size + 1 < size)
  56                 die("Data too large to fit into virtual memory space.");
  57         ret = xmalloc(size + 1);
  58         ((char*)ret)[size] = 0;
  59         return ret;
  60 }
  61
  62 /*
  63  * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
  64  * "data" to the allocated memory, zero terminates the allocated memory,
  65  * and returns a pointer to the allocated memory. If the allocation fails,
  66  * the program dies.
  67  */
  68 void *xmemdupz(const void *data, size_t len)
  69 {
  70         return memcpy(xmallocz(len), data, len);
  71 }
  72
  73 char *xstrndup(const char *str, size_t len)
  74 {
  75         char *p = memchr(str, '\0', len);
  76         return xmemdupz(str, p ? p - str : len);
  77 }
  78
  79 void *xrealloc(void *ptr, size_t size)
  80 {
  81         void *ret = realloc(ptr, size);
  82         if (!ret && !size)
  83                 ret = realloc(ptr, 1);
  84         if (!ret) {
  85                 try_to_free_routine(size);
  86                 ret = realloc(ptr, size);
  87                 if (!ret && !size)
  88                         ret = realloc(ptr, 1);
  89                 if (!ret)
  90                         die("Out of memory, realloc failed");
  91         }
  92         return ret;
  93 }
  94
  95 void *xcalloc(size_t nmemb, size_t size)
  96 {
  97         void *ret = calloc(nmemb, size);
  98         if (!ret && (!nmemb || !size))
  99                 ret = calloc(1, 1);
 100         if (!ret) {
 101                 try_to_free_routine(nmemb * size);
 102                 ret = calloc(nmemb, size);
 103                 if (!ret && (!nmemb || !size))
 104                         ret = calloc(1, 1);
 105                 if (!ret)
 106                         die("Out of memory, calloc failed");
 107         }
 108         return ret;
 109 }
 110
 111 /*
 112  * xread() is the same a read(), but it automatically restarts read()
 113  * operations with a recoverable error (EAGAIN and EINTR). xread()
 114  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 115  */
 116 ssize_t xread(int fd, void *buf, size_t len)
 117 {
 118         ssize_t nr;
 119         while (1) {
 120                 nr = read(fd, buf, len);
 121                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 122                         continue;
 123                 return nr;
 124         }
 125 }
 126
 127 /*
 128  * xwrite() is the same a write(), but it automatically restarts write()
 129  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 130  * GUARANTEE that "len" bytes is written even if the operation is successful.
 131  */
 132 ssize_t xwrite(int fd, const void *buf, size_t len)
 133 {
 134         ssize_t nr;
 135         while (1) {
 136                 nr = write(fd, buf, len);
 137                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 138                         continue;
 139                 return nr;
 140         }
 141 }
 142
 143 ssize_t read_in_full(int fd, void *buf, size_t count)
 144 {
 145         char *p = buf;
 146         ssize_t total = 0;
 147
 148         while (count > 0) {
 149                 ssize_t loaded = xread(fd, p, count);
 150                 if (loaded <= 0)
 151                         return total ? total : loaded;
 152                 count -= loaded;
 153                 p += loaded;
 154                 total += loaded;
 155         }
 156
 157         return total;
 158 }
 159
 160 ssize_t write_in_full(int fd, const void *buf, size_t count)
 161 {
 162         const char *p = buf;
 163         ssize_t total = 0;
 164
 165         while (count > 0) {
 166                 ssize_t written = xwrite(fd, p, count);
 167                 if (written < 0)
 168                         return -1;
 169                 if (!written) {
 170                         errno = ENOSPC;
 171                         return -1;
 172                 }
 173                 count -= written;
 174                 p += written;
 175                 total += written;
 176         }
 177
 178         return total;
 179 }
 180
 181 int xdup(int fd)
 182 {
 183         int ret = dup(fd);
 184         if (ret < 0)
 185                 die_errno("dup failed");
 186         return ret;
 187 }
 188
 189 FILE *xfdopen(int fd, const char *mode)
 190 {
 191         FILE *stream = fdopen(fd, mode);
 192         if (stream == NULL)
 193                 die_errno("Out of memory? fdopen failed");
 194         return stream;
 195 }
 196
 197 int xmkstemp(char *template)
 198 {
 199         int fd;
 200
 201         fd = mkstemp(template);
 202         if (fd < 0)
 203                 die_errno("Unable to create temporary file");
 204         return fd;
 205 }
 206
 207 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 208 int git_mkstemp(char *path, size_t len, const char *template)
 209 {
 210         const char *tmp;
 211         size_t n;
 212
 213         tmp = getenv("TMPDIR");
 214         if (!tmp)
 215                 tmp = "/tmp";
 216         n = snprintf(path, len, "%s/%s", tmp, template);
 217         if (len <= n) {
 218                 errno = ENAMETOOLONG;
 219                 return -1;
 220         }
 221         return mkstemp(path);
 222 }
 223
 224 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 225 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 226 {
 227         const char *tmp;
 228         size_t n;
 229
 230         tmp = getenv("TMPDIR");
 231         if (!tmp)
 232                 tmp = "/tmp";
 233         n = snprintf(path, len, "%s/%s", tmp, template);
 234         if (len <= n) {
 235                 errno = ENAMETOOLONG;
 236                 return -1;
 237         }
 238         return mkstemps(path, suffix_len);
 239 }
 240
 241 /* Adapted from libiberty's mkstemp.c. */
 242
 243 #undef TMP_MAX
 244 #define TMP_MAX 16384
 245
 246 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 247 {
 248         static const char letters[] =
 249                 "abcdefghijklmnopqrstuvwxyz"
 250                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 251                 "0123456789";
 252         static const int num_letters = 62;
 253         uint64_t value;
 254         struct timeval tv;
 255         char *template;
 256         size_t len;
 257         int fd, count;
 258
 259         len = strlen(pattern);
 260
 261         if (len < 6 + suffix_len) {
 262                 errno = EINVAL;
 263                 return -1;
 264         }
 265
 266         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 267                 errno = EINVAL;
 268                 return -1;
 269         }
 270
 271         /*
 272          * Replace pattern's XXXXXX characters with randomness.
 273          * Try TMP_MAX different filenames.
 274          */
 275         gettimeofday(&tv, NULL);
 276         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 277         template = &pattern[len - 6 - suffix_len];
 278         for (count = 0; count < TMP_MAX; ++count) {
 279                 uint64_t v = value;
 280                 /* Fill in the random bits. */
 281                 template[0] = letters[v % num_letters]; v /= num_letters;
 282                 template[1] = letters[v % num_letters]; v /= num_letters;
 283                 template[2] = letters[v % num_letters]; v /= num_letters;
 284                 template[3] = letters[v % num_letters]; v /= num_letters;
 285                 template[4] = letters[v % num_letters]; v /= num_letters;
 286                 template[5] = letters[v % num_letters]; v /= num_letters;
 287
 288                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 289                 if (fd > 0)
 290                         return fd;
 291                 /*
 292                  * Fatal error (EPERM, ENOSPC etc).
 293                  * It doesn't make sense to loop.
 294                  */
 295                 if (errno != EEXIST)
 296                         break;
 297                 /*
 298                  * This is a random value.  It is only necessary that
 299                  * the next TMP_MAX values generated by adding 7777 to
 300                  * VALUE are different with (module 2^32).
 301                  */
 302                 value += 7777;
 303         }
 304         /* We return the null string if we can't find a unique file name.  */
 305         pattern[0] = '\0';
 306         return -1;
 307 }
 308
 309 int git_mkstemp_mode(char *pattern, int mode)
 310 {
 311         /* mkstemp is just mkstemps with no suffix */
 312         return git_mkstemps_mode(pattern, 0, mode);
 313 }
 314
 315 int gitmkstemps(char *pattern, int suffix_len)
 316 {
 317         return git_mkstemps_mode(pattern, suffix_len, 0600);
 318 }
 319
 320 int xmkstemp_mode(char *template, int mode)
 321 {
 322         int fd;
 323
 324         fd = git_mkstemp_mode(template, mode);
 325         if (fd < 0)
 326                 die_errno("Unable to create temporary file");
 327         return fd;
 328 }
 329
 330 /*
 331  * zlib wrappers to make sure we don't silently miss errors
 332  * at init time.
 333  */
 334 void git_inflate_init(z_streamp strm)
 335 {
 336         const char *err;
 337
 338         switch (inflateInit(strm)) {
 339         case Z_OK:
 340                 return;
 341
 342         case Z_MEM_ERROR:
 343                 err = "out of memory";
 344                 break;
 345         case Z_VERSION_ERROR:
 346                 err = "wrong version";
 347                 break;
 348         default:
 349                 err = "error";
 350         }
 351         die("inflateInit: %s (%s)", err, strm->msg ? strm->msg : "no message");
 352 }
 353
 354 void git_inflate_end(z_streamp strm)
 355 {
 356         if (inflateEnd(strm) != Z_OK)
 357                 error("inflateEnd: %s", strm->msg ? strm->msg : "failed");
 358 }
 359
 360 int git_inflate(z_streamp strm, int flush)
 361 {
 362         int ret = inflate(strm, flush);
 363         const char *err;
 364
 365         switch (ret) {
 366         /* Out of memory is fatal. */
 367         case Z_MEM_ERROR:
 368                 die("inflate: out of memory");
 369
 370         /* Data corruption errors: we may want to recover from them (fsck) */
 371         case Z_NEED_DICT:
 372                 err = "needs dictionary"; break;
 373         case Z_DATA_ERROR:
 374                 err = "data stream error"; break;
 375         case Z_STREAM_ERROR:
 376                 err = "stream consistency error"; break;
 377         default:
 378                 err = "unknown error"; break;
 379
 380         /* Z_BUF_ERROR: normal, needs more space in the output buffer */
 381         case Z_BUF_ERROR:
 382         case Z_OK:
 383         case Z_STREAM_END:
 384                 return ret;
 385         }
 386         error("inflate: %s (%s)", err, strm->msg ? strm->msg : "no message");
 387         return ret;
 388 }
 389
 390 static int warn_if_unremovable(const char *op, const char *file, int rc)
 391 {
 392         if (rc < 0) {
 393                 int err = errno;
 394                 if (ENOENT != err) {
 395                         warning("unable to %s %s: %s",
 396                                 op, file, strerror(errno));
 397                         errno = err;
 398                 }
 399         }
 400         return rc;
 401 }
 402
 403 int unlink_or_warn(const char *file)
 404 {
 405         return warn_if_unremovable("unlink", file, unlink(file));
 406 }
 407
 408 int rmdir_or_warn(const char *file)
 409 {
 410         return warn_if_unremovable("rmdir", file, rmdir(file));
 411 }
 412
 413 int remove_or_warn(unsigned int mode, const char *file)
 414 {
 415         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 416 }