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
 202         fd = mkstemp(template);
 203         if (fd < 0)
 204                 die_errno("Unable to create temporary file");
 205         return fd;
 206 }
 207
 208 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 209 int git_mkstemp(char *path, size_t len, const char *template)
 210 {
 211         const char *tmp;
 212         size_t n;
 213
 214         tmp = getenv("TMPDIR");
 215         if (!tmp)
 216                 tmp = "/tmp";
 217         n = snprintf(path, len, "%s/%s", tmp, template);
 218         if (len <= n) {
 219                 errno = ENAMETOOLONG;
 220                 return -1;
 221         }
 222         return mkstemp(path);
 223 }
 224
 225 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 226 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 227 {
 228         const char *tmp;
 229         size_t n;
 230
 231         tmp = getenv("TMPDIR");
 232         if (!tmp)
 233                 tmp = "/tmp";
 234         n = snprintf(path, len, "%s/%s", tmp, template);
 235         if (len <= n) {
 236                 errno = ENAMETOOLONG;
 237                 return -1;
 238         }
 239         return mkstemps(path, suffix_len);
 240 }
 241
 242 /* Adapted from libiberty's mkstemp.c. */
 243
 244 #undef TMP_MAX
 245 #define TMP_MAX 16384
 246
 247 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 248 {
 249         static const char letters[] =
 250                 "abcdefghijklmnopqrstuvwxyz"
 251                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 252                 "0123456789";
 253         static const int num_letters = 62;
 254         uint64_t value;
 255         struct timeval tv;
 256         char *template;
 257         size_t len;
 258         int fd, count;
 259
 260         len = strlen(pattern);
 261
 262         if (len < 6 + suffix_len) {
 263                 errno = EINVAL;
 264                 return -1;
 265         }
 266
 267         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 268                 errno = EINVAL;
 269                 return -1;
 270         }
 271
 272         /*
 273          * Replace pattern's XXXXXX characters with randomness.
 274          * Try TMP_MAX different filenames.
 275          */
 276         gettimeofday(&tv, NULL);
 277         value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 278         template = &pattern[len - 6 - suffix_len];
 279         for (count = 0; count < TMP_MAX; ++count) {
 280                 uint64_t v = value;
 281                 /* Fill in the random bits. */
 282                 template[0] = letters[v % num_letters]; v /= num_letters;
 283                 template[1] = letters[v % num_letters]; v /= num_letters;
 284                 template[2] = letters[v % num_letters]; v /= num_letters;
 285                 template[3] = letters[v % num_letters]; v /= num_letters;
 286                 template[4] = letters[v % num_letters]; v /= num_letters;
 287                 template[5] = letters[v % num_letters]; v /= num_letters;
 288
 289                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 290                 if (fd > 0)
 291                         return fd;
 292                 /*
 293                  * Fatal error (EPERM, ENOSPC etc).
 294                  * It doesn't make sense to loop.
 295                  */
 296                 if (errno != EEXIST)
 297                         break;
 298                 /*
 299                  * This is a random value.  It is only necessary that
 300                  * the next TMP_MAX values generated by adding 7777 to
 301                  * VALUE are different with (module 2^32).
 302                  */
 303                 value += 7777;
 304         }
 305         /* We return the null string if we can't find a unique file name.  */
 306         pattern[0] = '\0';
 307         return -1;
 308 }
 309
 310 int git_mkstemp_mode(char *pattern, int mode)
 311 {
 312         /* mkstemp is just mkstemps with no suffix */
 313         return git_mkstemps_mode(pattern, 0, mode);
 314 }
 315
 316 int gitmkstemps(char *pattern, int suffix_len)
 317 {
 318         return git_mkstemps_mode(pattern, suffix_len, 0600);
 319 }
 320
 321 int xmkstemp_mode(char *template, int mode)
 322 {
 323         int fd;
 324
 325         fd = git_mkstemp_mode(template, mode);
 326         if (fd < 0)
 327                 die_errno("Unable to create temporary file");
 328         return fd;
 329 }
 330
 331 static int warn_if_unremovable(const char *op, const char *file, int rc)
 332 {
 333         if (rc < 0) {
 334                 int err = errno;
 335                 if (ENOENT != err) {
 336                         warning("unable to %s %s: %s",
 337                                 op, file, strerror(errno));
 338                         errno = err;
 339                 }
 340         }
 341         return rc;
 342 }
 343
 344 int unlink_or_warn(const char *file)
 345 {
 346         return warn_if_unremovable("unlink", file, unlink(file));
 347 }
 348
 349 int rmdir_or_warn(const char *file)
 350 {
 351         return warn_if_unremovable("rmdir", file, rmdir(file));
 352 }
 353
 354 int remove_or_warn(unsigned int mode, const char *file)
 355 {
 356         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 357 }