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
  12try_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
  21char *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
  33void *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
  53void *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 */
  69void *xmemdupz(const void *data, size_t len)
  70{
  71        return memcpy(xmallocz(len), data, len);
  72}
  73
  74char *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
  80void *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
  96void *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 */
 117ssize_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 */
 133ssize_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
 144ssize_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 -1;
 153                if (loaded == 0)
 154                        return total;
 155                count -= loaded;
 156                p += loaded;
 157                total += loaded;
 158        }
 159
 160        return total;
 161}
 162
 163ssize_t write_in_full(int fd, const void *buf, size_t count)
 164{
 165        const char *p = buf;
 166        ssize_t total = 0;
 167
 168        while (count > 0) {
 169                ssize_t written = xwrite(fd, p, count);
 170                if (written < 0)
 171                        return -1;
 172                if (!written) {
 173                        errno = ENOSPC;
 174                        return -1;
 175                }
 176                count -= written;
 177                p += written;
 178                total += written;
 179        }
 180
 181        return total;
 182}
 183
 184int xdup(int fd)
 185{
 186        int ret = dup(fd);
 187        if (ret < 0)
 188                die_errno("dup failed");
 189        return ret;
 190}
 191
 192FILE *xfdopen(int fd, const char *mode)
 193{
 194        FILE *stream = fdopen(fd, mode);
 195        if (stream == NULL)
 196                die_errno("Out of memory? fdopen failed");
 197        return stream;
 198}
 199
 200int xmkstemp(char *template)
 201{
 202        int fd;
 203        char origtemplate[PATH_MAX];
 204        strlcpy(origtemplate, template, sizeof(origtemplate));
 205
 206        fd = mkstemp(template);
 207        if (fd < 0) {
 208                int saved_errno = errno;
 209                const char *nonrelative_template;
 210
 211                if (!template[0])
 212                        template = origtemplate;
 213
 214                nonrelative_template = absolute_path(template);
 215                errno = saved_errno;
 216                die_errno("Unable to create temporary file '%s'",
 217                        nonrelative_template);
 218        }
 219        return fd;
 220}
 221
 222/* git_mkstemp() - create tmp file honoring TMPDIR variable */
 223int git_mkstemp(char *path, size_t len, const char *template)
 224{
 225        const char *tmp;
 226        size_t n;
 227
 228        tmp = getenv("TMPDIR");
 229        if (!tmp)
 230                tmp = "/tmp";
 231        n = snprintf(path, len, "%s/%s", tmp, template);
 232        if (len <= n) {
 233                errno = ENAMETOOLONG;
 234                return -1;
 235        }
 236        return mkstemp(path);
 237}
 238
 239/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 240int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 241{
 242        const char *tmp;
 243        size_t n;
 244
 245        tmp = getenv("TMPDIR");
 246        if (!tmp)
 247                tmp = "/tmp";
 248        n = snprintf(path, len, "%s/%s", tmp, template);
 249        if (len <= n) {
 250                errno = ENAMETOOLONG;
 251                return -1;
 252        }
 253        return mkstemps(path, suffix_len);
 254}
 255
 256/* Adapted from libiberty's mkstemp.c. */
 257
 258#undef TMP_MAX
 259#define TMP_MAX 16384
 260
 261int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 262{
 263        static const char letters[] =
 264                "abcdefghijklmnopqrstuvwxyz"
 265                "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 266                "0123456789";
 267        static const int num_letters = 62;
 268        uint64_t value;
 269        struct timeval tv;
 270        char *template;
 271        size_t len;
 272        int fd, count;
 273
 274        len = strlen(pattern);
 275
 276        if (len < 6 + suffix_len) {
 277                errno = EINVAL;
 278                return -1;
 279        }
 280
 281        if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 282                errno = EINVAL;
 283                return -1;
 284        }
 285
 286        /*
 287         * Replace pattern's XXXXXX characters with randomness.
 288         * Try TMP_MAX different filenames.
 289         */
 290        gettimeofday(&tv, NULL);
 291        value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 292        template = &pattern[len - 6 - suffix_len];
 293        for (count = 0; count < TMP_MAX; ++count) {
 294                uint64_t v = value;
 295                /* Fill in the random bits. */
 296                template[0] = letters[v % num_letters]; v /= num_letters;
 297                template[1] = letters[v % num_letters]; v /= num_letters;
 298                template[2] = letters[v % num_letters]; v /= num_letters;
 299                template[3] = letters[v % num_letters]; v /= num_letters;
 300                template[4] = letters[v % num_letters]; v /= num_letters;
 301                template[5] = letters[v % num_letters]; v /= num_letters;
 302
 303                fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 304                if (fd > 0)
 305                        return fd;
 306                /*
 307                 * Fatal error (EPERM, ENOSPC etc).
 308                 * It doesn't make sense to loop.
 309                 */
 310                if (errno != EEXIST)
 311                        break;
 312                /*
 313                 * This is a random value.  It is only necessary that
 314                 * the next TMP_MAX values generated by adding 7777 to
 315                 * VALUE are different with (module 2^32).
 316                 */
 317                value += 7777;
 318        }
 319        /* We return the null string if we can't find a unique file name.  */
 320        pattern[0] = '\0';
 321        return -1;
 322}
 323
 324int git_mkstemp_mode(char *pattern, int mode)
 325{
 326        /* mkstemp is just mkstemps with no suffix */
 327        return git_mkstemps_mode(pattern, 0, mode);
 328}
 329
 330int gitmkstemps(char *pattern, int suffix_len)
 331{
 332        return git_mkstemps_mode(pattern, suffix_len, 0600);
 333}
 334
 335int xmkstemp_mode(char *template, int mode)
 336{
 337        int fd;
 338        char origtemplate[PATH_MAX];
 339        strlcpy(origtemplate, template, sizeof(origtemplate));
 340
 341        fd = git_mkstemp_mode(template, mode);
 342        if (fd < 0) {
 343                int saved_errno = errno;
 344                const char *nonrelative_template;
 345
 346                if (!template[0])
 347                        template = origtemplate;
 348
 349                nonrelative_template = absolute_path(template);
 350                errno = saved_errno;
 351                die_errno("Unable to create temporary file '%s'",
 352                        nonrelative_template);
 353        }
 354        return fd;
 355}
 356
 357static int warn_if_unremovable(const char *op, const char *file, int rc)
 358{
 359        if (rc < 0) {
 360                int err = errno;
 361                if (ENOENT != err) {
 362                        warning("unable to %s %s: %s",
 363                                op, file, strerror(errno));
 364                        errno = err;
 365                }
 366        }
 367        return rc;
 368}
 369
 370int unlink_or_warn(const char *file)
 371{
 372        return warn_if_unremovable("unlink", file, unlink(file));
 373}
 374
 375int rmdir_or_warn(const char *file)
 376{
 377        return warn_if_unremovable("rmdir", file, rmdir(file));
 378}
 379
 380int remove_or_warn(unsigned int mode, const char *file)
 381{
 382        return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 383}