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