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