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 total ? total : loaded;
 153                count -= loaded;
 154                p += loaded;
 155                total += loaded;
 156        }
 157
 158        return total;
 159}
 160
 161ssize_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
 182int xdup(int fd)
 183{
 184        int ret = dup(fd);
 185        if (ret < 0)
 186                die_errno("dup failed");
 187        return ret;
 188}
 189
 190FILE *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
 198int 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 */
 209int 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. */
 226int 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
 247int 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
 310int 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
 316int gitmkstemps(char *pattern, int suffix_len)
 317{
 318        return git_mkstemps_mode(pattern, suffix_len, 0600);
 319}
 320
 321int 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
 331static 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
 344int unlink_or_warn(const char *file)
 345{
 346        return warn_if_unremovable("unlink", file, unlink(file));
 347}
 348
 349int rmdir_or_warn(const char *file)
 350{
 351        return warn_if_unremovable("rmdir", file, rmdir(file));
 352}
 353
 354int remove_or_warn(unsigned int mode, const char *file)
 355{
 356        return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 357}