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 #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 ssize_t read_in_full(int fd, void *buf, size_t count)
 178 {
 179         char *p = buf;
 180         ssize_t total = 0;
 181
 182         while (count > 0) {
 183                 ssize_t loaded = xread(fd, p, count);
 184                 if (loaded < 0)
 185                         return -1;
 186                 if (loaded == 0)
 187                         return total;
 188                 count -= loaded;
 189                 p += loaded;
 190                 total += loaded;
 191         }
 192
 193         return total;
 194 }
 195
 196 ssize_t write_in_full(int fd, const void *buf, size_t count)
 197 {
 198         const char *p = buf;
 199         ssize_t total = 0;
 200
 201         while (count > 0) {
 202                 ssize_t written = xwrite(fd, p, count);
 203                 if (written < 0)
 204                         return -1;
 205                 if (!written) {
 206                         errno = ENOSPC;
 207                         return -1;
 208                 }
 209                 count -= written;
 210                 p += written;
 211                 total += written;
 212         }
 213
 214         return total;
 215 }
 216
 217 int xdup(int fd)
 218 {
 219         int ret = dup(fd);
 220         if (ret < 0)
 221                 die_errno("dup failed");
 222         return ret;
 223 }
 224
 225 FILE *xfdopen(int fd, const char *mode)
 226 {
 227         FILE *stream = fdopen(fd, mode);
 228         if (stream == NULL)
 229                 die_errno("Out of memory? fdopen failed");
 230         return stream;
 231 }
 232
 233 int xmkstemp(char *template)
 234 {
 235         int fd;
 236         char origtemplate[PATH_MAX];
 237         strlcpy(origtemplate, template, sizeof(origtemplate));
 238
 239         fd = mkstemp(template);
 240         if (fd < 0) {
 241                 int saved_errno = errno;
 242                 const char *nonrelative_template;
 243
 244                 if (strlen(template) != strlen(origtemplate))
 245                         template = origtemplate;
 246
 247                 nonrelative_template = absolute_path(template);
 248                 errno = saved_errno;
 249                 die_errno("Unable to create temporary file '%s'",
 250                         nonrelative_template);
 251         }
 252         return fd;
 253 }
 254
 255 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 256 int git_mkstemp(char *path, size_t len, const char *template)
 257 {
 258         const char *tmp;
 259         size_t n;
 260
 261         tmp = getenv("TMPDIR");
 262         if (!tmp)
 263                 tmp = "/tmp";
 264         n = snprintf(path, len, "%s/%s", tmp, template);
 265         if (len <= n) {
 266                 errno = ENAMETOOLONG;
 267                 return -1;
 268         }
 269         return mkstemp(path);
 270 }
 271
 272 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 273 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 274 {
 275         const char *tmp;
 276         size_t n;
 277
 278         tmp = getenv("TMPDIR");
 279         if (!tmp)
 280                 tmp = "/tmp";
 281         n = snprintf(path, len, "%s/%s", tmp, template);
 282         if (len <= n) {
 283                 errno = ENAMETOOLONG;
 284                 return -1;
 285         }
 286         return mkstemps(path, suffix_len);
 287 }
 288
 289 /* Adapted from libiberty's mkstemp.c. */
 290
 291 #undef TMP_MAX
 292 #define TMP_MAX 16384
 293
 294 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 295 {
 296         static const char letters[] =
 297                 "abcdefghijklmnopqrstuvwxyz"
 298                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 299                 "0123456789";
 300         static const int num_letters = 62;
 301         uint64_t value;
 302         struct timeval tv;
 303         char *template;
 304         size_t len;
 305         int fd, count;
 306
 307         len = strlen(pattern);
 308
 309         if (len < 6 + suffix_len) {
 310                 errno = EINVAL;
 311                 return -1;
 312         }
 313
 314         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 315                 errno = EINVAL;
 316                 return -1;
 317         }
 318
 319         /*
 320          * Replace pattern's XXXXXX characters with randomness.
 321          * Try TMP_MAX different filenames.
 322          */
 323         gettimeofday(&tv, NULL);
 324         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 325         template = &pattern[len - 6 - suffix_len];
 326         for (count = 0; count < TMP_MAX; ++count) {
 327                 uint64_t v = value;
 328                 /* Fill in the random bits. */
 329                 template[0] = letters[v % num_letters]; v /= num_letters;
 330                 template[1] = letters[v % num_letters]; v /= num_letters;
 331                 template[2] = letters[v % num_letters]; v /= num_letters;
 332                 template[3] = letters[v % num_letters]; v /= num_letters;
 333                 template[4] = letters[v % num_letters]; v /= num_letters;
 334                 template[5] = letters[v % num_letters]; v /= num_letters;
 335
 336                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 337                 if (fd >= 0)
 338                         return fd;
 339                 /*
 340                  * Fatal error (EPERM, ENOSPC etc).
 341                  * It doesn't make sense to loop.
 342                  */
 343                 if (errno != EEXIST)
 344                         break;
 345                 /*
 346                  * This is a random value.  It is only necessary that
 347                  * the next TMP_MAX values generated by adding 7777 to
 348                  * VALUE are different with (module 2^32).
 349                  */
 350                 value += 7777;
 351         }
 352         /* We return the null string if we can't find a unique file name.  */
 353         pattern[0] = '\0';
 354         return -1;
 355 }
 356
 357 int git_mkstemp_mode(char *pattern, int mode)
 358 {
 359         /* mkstemp is just mkstemps with no suffix */
 360         return git_mkstemps_mode(pattern, 0, mode);
 361 }
 362
 363 #ifdef NO_MKSTEMPS
 364 int gitmkstemps(char *pattern, int suffix_len)
 365 {
 366         return git_mkstemps_mode(pattern, suffix_len, 0600);
 367 }
 368 #endif
 369
 370 int xmkstemp_mode(char *template, int mode)
 371 {
 372         int fd;
 373         char origtemplate[PATH_MAX];
 374         strlcpy(origtemplate, template, sizeof(origtemplate));
 375
 376         fd = git_mkstemp_mode(template, mode);
 377         if (fd < 0) {
 378                 int saved_errno = errno;
 379                 const char *nonrelative_template;
 380
 381                 if (!template[0])
 382                         template = origtemplate;
 383
 384                 nonrelative_template = absolute_path(template);
 385                 errno = saved_errno;
 386                 die_errno("Unable to create temporary file '%s'",
 387                         nonrelative_template);
 388         }
 389         return fd;
 390 }
 391
 392 static int warn_if_unremovable(const char *op, const char *file, int rc)
 393 {
 394         if (rc < 0) {
 395                 int err = errno;
 396                 if (ENOENT != err) {
 397                         warning("unable to %s %s: %s",
 398                                 op, file, strerror(errno));
 399                         errno = err;
 400                 }
 401         }
 402         return rc;
 403 }
 404
 405 int unlink_or_warn(const char *file)
 406 {
 407         return warn_if_unremovable("unlink", file, unlink(file));
 408 }
 409
 410 int rmdir_or_warn(const char *file)
 411 {
 412         return warn_if_unremovable("rmdir", file, rmdir(file));
 413 }
 414
 415 int remove_or_warn(unsigned int mode, const char *file)
 416 {
 417         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 418 }
 419
 420 void warn_on_inaccessible(const char *path)
 421 {
 422         warning(_("unable to access '%s': %s"), path, strerror(errno));
 423 }
 424
 425 static int access_error_is_ok(int err, unsigned flag)
 426 {
 427         return err == ENOENT || err == ENOTDIR ||
 428                 ((flag & ACCESS_EACCES_OK) && err == EACCES);
 429 }
 430
 431 int access_or_warn(const char *path, int mode, unsigned flag)
 432 {
 433         int ret = access(path, mode);
 434         if (ret && !access_error_is_ok(errno, flag))
 435                 warn_on_inaccessible(path);
 436         return ret;
 437 }
 438
 439 int access_or_die(const char *path, int mode, unsigned flag)
 440 {
 441         int ret = access(path, mode);
 442         if (ret && !access_error_is_ok(errno, flag))
 443                 die_errno(_("unable to access '%s'"), path);
 444         return ret;
 445 }
 446
 447 struct passwd *xgetpwuid_self(void)
 448 {
 449         struct passwd *pw;
 450
 451         errno = 0;
 452         pw = getpwuid(getuid());
 453         if (!pw)
 454                 die(_("unable to look up current user in the passwd file: %s"),
 455                     errno ? strerror(errno) : _("no such user"));
 456         return pw;
 457 }