Andrew's git - gitweb.git/blob

f92b14759833b1ae77070b4188d8ad8ea8d3799e
   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 * Limit size of IO chunks, because huge chunks only cause pain.  OS X
 135 * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
 136 * the absense of bugs, large chunks can result in bad latencies when
 137 * you decide to kill the process.
 138 */
 139#define MAX_IO_SIZE (8*1024*1024)
 140
 141/*
 142 * xread() is the same a read(), but it automatically restarts read()
 143 * operations with a recoverable error (EAGAIN and EINTR). xread()
 144 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 145 */
 146ssize_t xread(int fd, void *buf, size_t len)
 147{
 148        ssize_t nr;
 149        if (len > MAX_IO_SIZE)
 150            len = MAX_IO_SIZE;
 151        while (1) {
 152                nr = read(fd, buf, len);
 153                if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 154                        continue;
 155                return nr;
 156        }
 157}
 158
 159/*
 160 * xwrite() is the same a write(), but it automatically restarts write()
 161 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 162 * GUARANTEE that "len" bytes is written even if the operation is successful.
 163 */
 164ssize_t xwrite(int fd, const void *buf, size_t len)
 165{
 166        ssize_t nr;
 167        if (len > MAX_IO_SIZE)
 168            len = MAX_IO_SIZE;
 169        while (1) {
 170                nr = write(fd, buf, len);
 171                if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 172                        continue;
 173                return nr;
 174        }
 175}
 176
 177ssize_t read_in_full(int fd, void *buf, size_t count)
 178{
 179        char *p = buf;
 180        ssize_t total = 0;
 181
 182        while (count > 0) {
 183                ssize_t loaded = xread(fd, p, count);
 184                if (loaded < 0)
 185                        return -1;
 186                if (loaded == 0)
 187                        return total;
 188                count -= loaded;
 189                p += loaded;
 190                total += loaded;
 191        }
 192
 193        return total;
 194}
 195
 196ssize_t write_in_full(int fd, const void *buf, size_t count)
 197{
 198        const char *p = buf;
 199        ssize_t total = 0;
 200
 201        while (count > 0) {
 202                ssize_t written = xwrite(fd, p, count);
 203                if (written < 0)
 204                        return -1;
 205                if (!written) {
 206                        errno = ENOSPC;
 207                        return -1;
 208                }
 209                count -= written;
 210                p += written;
 211                total += written;
 212        }
 213
 214        return total;
 215}
 216
 217int xdup(int fd)
 218{
 219        int ret = dup(fd);
 220        if (ret < 0)
 221                die_errno("dup failed");
 222        return ret;
 223}
 224
 225FILE *xfdopen(int fd, const char *mode)
 226{
 227        FILE *stream = fdopen(fd, mode);
 228        if (stream == NULL)
 229                die_errno("Out of memory? fdopen failed");
 230        return stream;
 231}
 232
 233int xmkstemp(char *template)
 234{
 235        int fd;
 236        char origtemplate[PATH_MAX];
 237        strlcpy(origtemplate, template, sizeof(origtemplate));
 238
 239        fd = mkstemp(template);
 240        if (fd < 0) {
 241                int saved_errno = errno;
 242                const char *nonrelative_template;
 243
 244                if (strlen(template) != strlen(origtemplate))
 245                        template = origtemplate;
 246
 247                nonrelative_template = absolute_path(template);
 248                errno = saved_errno;
 249                die_errno("Unable to create temporary file '%s'",
 250                        nonrelative_template);
 251        }
 252        return fd;
 253}
 254
 255/* git_mkstemp() - create tmp file honoring TMPDIR variable */
 256int git_mkstemp(char *path, size_t len, const char *template)
 257{
 258        const char *tmp;
 259        size_t n;
 260
 261        tmp = getenv("TMPDIR");
 262        if (!tmp)
 263                tmp = "/tmp";
 264        n = snprintf(path, len, "%s/%s", tmp, template);
 265        if (len <= n) {
 266                errno = ENAMETOOLONG;
 267                return -1;
 268        }
 269        return mkstemp(path);
 270}
 271
 272/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 273int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 274{
 275        const char *tmp;
 276        size_t n;
 277
 278        tmp = getenv("TMPDIR");
 279        if (!tmp)
 280                tmp = "/tmp";
 281        n = snprintf(path, len, "%s/%s", tmp, template);
 282        if (len <= n) {
 283                errno = ENAMETOOLONG;
 284                return -1;
 285        }
 286        return mkstemps(path, suffix_len);
 287}
 288
 289/* Adapted from libiberty's mkstemp.c. */
 290
 291#undef TMP_MAX
 292#define TMP_MAX 16384
 293
 294int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 295{
 296        static const char letters[] =
 297                "abcdefghijklmnopqrstuvwxyz"
 298                "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 299                "0123456789";
 300        static const int num_letters = 62;
 301        uint64_t value;
 302        struct timeval tv;
 303        char *template;
 304        size_t len;
 305        int fd, count;
 306
 307        len = strlen(pattern);
 308
 309        if (len < 6 + suffix_len) {
 310                errno = EINVAL;
 311                return -1;
 312        }
 313
 314        if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 315                errno = EINVAL;
 316                return -1;
 317        }
 318
 319        /*
 320         * Replace pattern's XXXXXX characters with randomness.
 321         * Try TMP_MAX different filenames.
 322         */
 323        gettimeofday(&tv, NULL);
 324        value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 325        template = &pattern[len - 6 - suffix_len];
 326        for (count = 0; count < TMP_MAX; ++count) {
 327                uint64_t v = value;
 328                /* Fill in the random bits. */
 329                template[0] = letters[v % num_letters]; v /= num_letters;
 330                template[1] = letters[v % num_letters]; v /= num_letters;
 331                template[2] = letters[v % num_letters]; v /= num_letters;
 332                template[3] = letters[v % num_letters]; v /= num_letters;
 333                template[4] = letters[v % num_letters]; v /= num_letters;
 334                template[5] = letters[v % num_letters]; v /= num_letters;
 335
 336                fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 337                if (fd >= 0)
 338                        return fd;
 339                /*
 340                 * Fatal error (EPERM, ENOSPC etc).
 341                 * It doesn't make sense to loop.
 342                 */
 343                if (errno != EEXIST)
 344                        break;
 345                /*
 346                 * This is a random value.  It is only necessary that
 347                 * the next TMP_MAX values generated by adding 7777 to
 348                 * VALUE are different with (module 2^32).
 349                 */
 350                value += 7777;
 351        }
 352        /* We return the null string if we can't find a unique file name.  */
 353        pattern[0] = '\0';
 354        return -1;
 355}
 356
 357int git_mkstemp_mode(char *pattern, int mode)
 358{
 359        /* mkstemp is just mkstemps with no suffix */
 360        return git_mkstemps_mode(pattern, 0, mode);
 361}
 362
 363int gitmkstemps(char *pattern, int suffix_len)
 364{
 365        return git_mkstemps_mode(pattern, suffix_len, 0600);
 366}
 367
 368int xmkstemp_mode(char *template, int mode)
 369{
 370        int fd;
 371        char origtemplate[PATH_MAX];
 372        strlcpy(origtemplate, template, sizeof(origtemplate));
 373
 374        fd = git_mkstemp_mode(template, mode);
 375        if (fd < 0) {
 376                int saved_errno = errno;
 377                const char *nonrelative_template;
 378
 379                if (!template[0])
 380                        template = origtemplate;
 381
 382                nonrelative_template = absolute_path(template);
 383                errno = saved_errno;
 384                die_errno("Unable to create temporary file '%s'",
 385                        nonrelative_template);
 386        }
 387        return fd;
 388}
 389
 390static int warn_if_unremovable(const char *op, const char *file, int rc)
 391{
 392        if (rc < 0) {
 393                int err = errno;
 394                if (ENOENT != err) {
 395                        warning("unable to %s %s: %s",
 396                                op, file, strerror(errno));
 397                        errno = err;
 398                }
 399        }
 400        return rc;
 401}
 402
 403int unlink_or_warn(const char *file)
 404{
 405        return warn_if_unremovable("unlink", file, unlink(file));
 406}
 407
 408int rmdir_or_warn(const char *file)
 409{
 410        return warn_if_unremovable("rmdir", file, rmdir(file));
 411}
 412
 413int remove_or_warn(unsigned int mode, const char *file)
 414{
 415        return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 416}
 417
 418void warn_on_inaccessible(const char *path)
 419{
 420        warning(_("unable to access '%s': %s"), path, strerror(errno));
 421}
 422
 423static int access_error_is_ok(int err, unsigned flag)
 424{
 425        return err == ENOENT || err == ENOTDIR ||
 426                ((flag & ACCESS_EACCES_OK) && err == EACCES);
 427}
 428
 429int access_or_warn(const char *path, int mode, unsigned flag)
 430{
 431        int ret = access(path, mode);
 432        if (ret && !access_error_is_ok(errno, flag))
 433                warn_on_inaccessible(path);
 434        return ret;
 435}
 436
 437int access_or_die(const char *path, int mode, unsigned flag)
 438{
 439        int ret = access(path, mode);
 440        if (ret && !access_error_is_ok(errno, flag))
 441                die_errno(_("unable to access '%s'"), path);
 442        return ret;
 443}
 444
 445struct passwd *xgetpwuid_self(void)
 446{
 447        struct passwd *pw;
 448
 449        errno = 0;
 450        pw = getpwuid(getuid());
 451        if (!pw)
 452                die(_("unable to look up current user in the passwd file: %s"),
 453                    errno ? strerror(errno) : _("no such user"));
 454        return pw;
 455}