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