Andrew's git - gitweb.git/blob

   1/*
   2 * Various trivial helper wrappers around standard functions
   3 */
   4#include "cache.h"
   5
   6static void do_nothing(size_t size)
   7{
   8}
   9
  10static void (*try_to_free_routine)(size_t size) = do_nothing;
  11
  12static 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
  24try_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
  33char *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
  45void *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
  68void *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 */
  84void *xmemdupz(const void *data, size_t len)
  85{
  86        return memcpy(xmallocz(len), data, len);
  87}
  88
  89char *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
  95void *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
 114void *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 * xread() is the same a read(), but it automatically restarts read()
 135 * operations with a recoverable error (EAGAIN and EINTR). xread()
 136 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 137 */
 138ssize_t xread(int fd, void *buf, size_t len)
 139{
 140        ssize_t nr;
 141        while (1) {
 142                nr = read(fd, buf, len);
 143                if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 144                        continue;
 145                return nr;
 146        }
 147}
 148
 149/*
 150 * xwrite() is the same a write(), but it automatically restarts write()
 151 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 152 * GUARANTEE that "len" bytes is written even if the operation is successful.
 153 */
 154ssize_t xwrite(int fd, const void *buf, size_t len)
 155{
 156        ssize_t nr;
 157        while (1) {
 158                nr = write(fd, buf, len);
 159                if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 160                        continue;
 161                return nr;
 162        }
 163}
 164
 165ssize_t read_in_full(int fd, void *buf, size_t count)
 166{
 167        char *p = buf;
 168        ssize_t total = 0;
 169
 170        while (count > 0) {
 171                ssize_t loaded = xread(fd, p, count);
 172                if (loaded < 0)
 173                        return -1;
 174                if (loaded == 0)
 175                        return total;
 176                count -= loaded;
 177                p += loaded;
 178                total += loaded;
 179        }
 180
 181        return total;
 182}
 183
 184ssize_t write_in_full(int fd, const void *buf, size_t count)
 185{
 186        const char *p = buf;
 187        ssize_t total = 0;
 188
 189        while (count > 0) {
 190                ssize_t written = xwrite(fd, p, count);
 191                if (written < 0)
 192                        return -1;
 193                if (!written) {
 194                        errno = ENOSPC;
 195                        return -1;
 196                }
 197                count -= written;
 198                p += written;
 199                total += written;
 200        }
 201
 202        return total;
 203}
 204
 205int xdup(int fd)
 206{
 207        int ret = dup(fd);
 208        if (ret < 0)
 209                die_errno("dup failed");
 210        return ret;
 211}
 212
 213FILE *xfdopen(int fd, const char *mode)
 214{
 215        FILE *stream = fdopen(fd, mode);
 216        if (stream == NULL)
 217                die_errno("Out of memory? fdopen failed");
 218        return stream;
 219}
 220
 221int xmkstemp(char *template)
 222{
 223        int fd;
 224        char origtemplate[PATH_MAX];
 225        strlcpy(origtemplate, template, sizeof(origtemplate));
 226
 227        fd = mkstemp(template);
 228        if (fd < 0) {
 229                int saved_errno = errno;
 230                const char *nonrelative_template;
 231
 232                if (!template[0])
 233                        template = origtemplate;
 234
 235                nonrelative_template = absolute_path(template);
 236                errno = saved_errno;
 237                die_errno("Unable to create temporary file '%s'",
 238                        nonrelative_template);
 239        }
 240        return fd;
 241}
 242
 243/* git_mkstemp() - create tmp file honoring TMPDIR variable */
 244int git_mkstemp(char *path, size_t len, const char *template)
 245{
 246        const char *tmp;
 247        size_t n;
 248
 249        tmp = getenv("TMPDIR");
 250        if (!tmp)
 251                tmp = "/tmp";
 252        n = snprintf(path, len, "%s/%s", tmp, template);
 253        if (len <= n) {
 254                errno = ENAMETOOLONG;
 255                return -1;
 256        }
 257        return mkstemp(path);
 258}
 259
 260/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 261int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 262{
 263        const char *tmp;
 264        size_t n;
 265
 266        tmp = getenv("TMPDIR");
 267        if (!tmp)
 268                tmp = "/tmp";
 269        n = snprintf(path, len, "%s/%s", tmp, template);
 270        if (len <= n) {
 271                errno = ENAMETOOLONG;
 272                return -1;
 273        }
 274        return mkstemps(path, suffix_len);
 275}
 276
 277/* Adapted from libiberty's mkstemp.c. */
 278
 279#undef TMP_MAX
 280#define TMP_MAX 16384
 281
 282int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 283{
 284        static const char letters[] =
 285                "abcdefghijklmnopqrstuvwxyz"
 286                "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 287                "0123456789";
 288        static const int num_letters = 62;
 289        uint64_t value;
 290        struct timeval tv;
 291        char *template;
 292        size_t len;
 293        int fd, count;
 294
 295        len = strlen(pattern);
 296
 297        if (len < 6 + suffix_len) {
 298                errno = EINVAL;
 299                return -1;
 300        }
 301
 302        if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 303                errno = EINVAL;
 304                return -1;
 305        }
 306
 307        /*
 308         * Replace pattern's XXXXXX characters with randomness.
 309         * Try TMP_MAX different filenames.
 310         */
 311        gettimeofday(&tv, NULL);
 312        value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 313        template = &pattern[len - 6 - suffix_len];
 314        for (count = 0; count < TMP_MAX; ++count) {
 315                uint64_t v = value;
 316                /* Fill in the random bits. */
 317                template[0] = letters[v % num_letters]; v /= num_letters;
 318                template[1] = letters[v % num_letters]; v /= num_letters;
 319                template[2] = letters[v % num_letters]; v /= num_letters;
 320                template[3] = letters[v % num_letters]; v /= num_letters;
 321                template[4] = letters[v % num_letters]; v /= num_letters;
 322                template[5] = letters[v % num_letters]; v /= num_letters;
 323
 324                fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 325                if (fd > 0)
 326                        return fd;
 327                /*
 328                 * Fatal error (EPERM, ENOSPC etc).
 329                 * It doesn't make sense to loop.
 330                 */
 331                if (errno != EEXIST)
 332                        break;
 333                /*
 334                 * This is a random value.  It is only necessary that
 335                 * the next TMP_MAX values generated by adding 7777 to
 336                 * VALUE are different with (module 2^32).
 337                 */
 338                value += 7777;
 339        }
 340        /* We return the null string if we can't find a unique file name.  */
 341        pattern[0] = '\0';
 342        return -1;
 343}
 344
 345int git_mkstemp_mode(char *pattern, int mode)
 346{
 347        /* mkstemp is just mkstemps with no suffix */
 348        return git_mkstemps_mode(pattern, 0, mode);
 349}
 350
 351int gitmkstemps(char *pattern, int suffix_len)
 352{
 353        return git_mkstemps_mode(pattern, suffix_len, 0600);
 354}
 355
 356int xmkstemp_mode(char *template, int mode)
 357{
 358        int fd;
 359        char origtemplate[PATH_MAX];
 360        strlcpy(origtemplate, template, sizeof(origtemplate));
 361
 362        fd = git_mkstemp_mode(template, mode);
 363        if (fd < 0) {
 364                int saved_errno = errno;
 365                const char *nonrelative_template;
 366
 367                if (!template[0])
 368                        template = origtemplate;
 369
 370                nonrelative_template = absolute_path(template);
 371                errno = saved_errno;
 372                die_errno("Unable to create temporary file '%s'",
 373                        nonrelative_template);
 374        }
 375        return fd;
 376}
 377
 378static int warn_if_unremovable(const char *op, const char *file, int rc)
 379{
 380        if (rc < 0) {
 381                int err = errno;
 382                if (ENOENT != err) {
 383                        warning("unable to %s %s: %s",
 384                                op, file, strerror(errno));
 385                        errno = err;
 386                }
 387        }
 388        return rc;
 389}
 390
 391int unlink_or_warn(const char *file)
 392{
 393        return warn_if_unremovable("unlink", file, unlink(file));
 394}
 395
 396int rmdir_or_warn(const char *file)
 397{
 398        return warn_if_unremovable("rmdir", file, rmdir(file));
 399}
 400
 401int remove_or_warn(unsigned int mode, const char *file)
 402{
 403        return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 404}