wrapper.c

   1 /*
   2  * Various trivial helper wrappers around standard functions
   3  */
   4 #include "cache.h"
   5 #include "config.h"
   6
   7 static int memory_limit_check(size_t size, int gentle)
   8 {
   9         static size_t limit = 0;
  10         if (!limit) {
  11                 limit = git_env_ulong("GIT_ALLOC_LIMIT", 0);
  12                 if (!limit)
  13                         limit = SIZE_MAX;
  14         }
  15         if (size > limit) {
  16                 if (gentle) {
  17                         error("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
  18                               (uintmax_t)size, (uintmax_t)limit);
  19                         return -1;
  20                 } else
  21                         die("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
  22                             (uintmax_t)size, (uintmax_t)limit);
  23         }
  24         return 0;
  25 }
  26
  27 char *xstrdup(const char *str)
  28 {
  29         char *ret = strdup(str);
  30         if (!ret)
  31                 die("Out of memory, strdup failed");
  32         return ret;
  33 }
  34
  35 static void *do_xmalloc(size_t size, int gentle)
  36 {
  37         void *ret;
  38
  39         if (memory_limit_check(size, gentle))
  40                 return NULL;
  41         ret = malloc(size);
  42         if (!ret && !size)
  43                 ret = malloc(1);
  44         if (!ret) {
  45                 if (!gentle)
  46                         die("Out of memory, malloc failed (tried to allocate %lu bytes)",
  47                             (unsigned long)size);
  48                 else {
  49                         error("Out of memory, malloc failed (tried to allocate %lu bytes)",
  50                               (unsigned long)size);
  51                         return NULL;
  52                 }
  53         }
  54 #ifdef XMALLOC_POISON
  55         memset(ret, 0xA5, size);
  56 #endif
  57         return ret;
  58 }
  59
  60 void *xmalloc(size_t size)
  61 {
  62         return do_xmalloc(size, 0);
  63 }
  64
  65 static void *do_xmallocz(size_t size, int gentle)
  66 {
  67         void *ret;
  68         if (unsigned_add_overflows(size, 1)) {
  69                 if (gentle) {
  70                         error("Data too large to fit into virtual memory space.");
  71                         return NULL;
  72                 } else
  73                         die("Data too large to fit into virtual memory space.");
  74         }
  75         ret = do_xmalloc(size + 1, gentle);
  76         if (ret)
  77                 ((char*)ret)[size] = 0;
  78         return ret;
  79 }
  80
  81 void *xmallocz(size_t size)
  82 {
  83         return do_xmallocz(size, 0);
  84 }
  85
  86 void *xmallocz_gently(size_t size)
  87 {
  88         return do_xmallocz(size, 1);
  89 }
  90
  91 /*
  92  * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
  93  * "data" to the allocated memory, zero terminates the allocated memory,
  94  * and returns a pointer to the allocated memory. If the allocation fails,
  95  * the program dies.
  96  */
  97 void *xmemdupz(const void *data, size_t len)
  98 {
  99         return memcpy(xmallocz(len), data, len);
 100 }
 101
 102 char *xstrndup(const char *str, size_t len)
 103 {
 104         char *p = memchr(str, '\0', len);
 105         return xmemdupz(str, p ? p - str : len);
 106 }
 107
 108 void *xrealloc(void *ptr, size_t size)
 109 {
 110         void *ret;
 111
 112         memory_limit_check(size, 0);
 113         ret = realloc(ptr, size);
 114         if (!ret && !size)
 115                 ret = realloc(ptr, 1);
 116         if (!ret)
 117                 die("Out of memory, realloc failed");
 118         return ret;
 119 }
 120
 121 void *xcalloc(size_t nmemb, size_t size)
 122 {
 123         void *ret;
 124
 125         if (unsigned_mult_overflows(nmemb, size))
 126                 die("data too large to fit into virtual memory space");
 127
 128         memory_limit_check(size * nmemb, 0);
 129         ret = calloc(nmemb, size);
 130         if (!ret && (!nmemb || !size))
 131                 ret = calloc(1, 1);
 132         if (!ret)
 133                 die("Out of memory, calloc failed");
 134         return ret;
 135 }
 136
 137 /*
 138  * Limit size of IO chunks, because huge chunks only cause pain.  OS X
 139  * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
 140  * the absence of bugs, large chunks can result in bad latencies when
 141  * you decide to kill the process.
 142  *
 143  * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
 144  * that is smaller than that, clip it to SSIZE_MAX, as a call to
 145  * read(2) or write(2) larger than that is allowed to fail.  As the last
 146  * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
 147  * to override this, if the definition of SSIZE_MAX given by the platform
 148  * is broken.
 149  */
 150 #ifndef MAX_IO_SIZE
 151 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
 152 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
 153 #  define MAX_IO_SIZE SSIZE_MAX
 154 # else
 155 #  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
 156 # endif
 157 #endif
 158
 159 /**
 160  * xopen() is the same as open(), but it die()s if the open() fails.
 161  */
 162 int xopen(const char *path, int oflag, ...)
 163 {
 164         mode_t mode = 0;
 165         va_list ap;
 166
 167         /*
 168          * va_arg() will have undefined behavior if the specified type is not
 169          * compatible with the argument type. Since integers are promoted to
 170          * ints, we fetch the next argument as an int, and then cast it to a
 171          * mode_t to avoid undefined behavior.
 172          */
 173         va_start(ap, oflag);
 174         if (oflag & O_CREAT)
 175                 mode = va_arg(ap, int);
 176         va_end(ap);
 177
 178         for (;;) {
 179                 int fd = open(path, oflag, mode);
 180                 if (fd >= 0)
 181                         return fd;
 182                 if (errno == EINTR)
 183                         continue;
 184
 185                 if ((oflag & O_RDWR) == O_RDWR)
 186                         die_errno(_("could not open '%s' for reading and writing"), path);
 187                 else if ((oflag & O_WRONLY) == O_WRONLY)
 188                         die_errno(_("could not open '%s' for writing"), path);
 189                 else
 190                         die_errno(_("could not open '%s' for reading"), path);
 191         }
 192 }
 193
 194 static int handle_nonblock(int fd, short poll_events, int err)
 195 {
 196         struct pollfd pfd;
 197
 198         if (err != EAGAIN && err != EWOULDBLOCK)
 199                 return 0;
 200
 201         pfd.fd = fd;
 202         pfd.events = poll_events;
 203
 204         /*
 205          * no need to check for errors, here;
 206          * a subsequent read/write will detect unrecoverable errors
 207          */
 208         poll(&pfd, 1, -1);
 209         return 1;
 210 }
 211
 212 /*
 213  * xread() is the same a read(), but it automatically restarts read()
 214  * operations with a recoverable error (EAGAIN and EINTR). xread()
 215  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 216  */
 217 ssize_t xread(int fd, void *buf, size_t len)
 218 {
 219         ssize_t nr;
 220         if (len > MAX_IO_SIZE)
 221             len = MAX_IO_SIZE;
 222         while (1) {
 223                 nr = read(fd, buf, len);
 224                 if (nr < 0) {
 225                         if (errno == EINTR)
 226                                 continue;
 227                         if (handle_nonblock(fd, POLLIN, errno))
 228                                 continue;
 229                 }
 230                 return nr;
 231         }
 232 }
 233
 234 /*
 235  * xwrite() is the same a write(), but it automatically restarts write()
 236  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 237  * GUARANTEE that "len" bytes is written even if the operation is successful.
 238  */
 239 ssize_t xwrite(int fd, const void *buf, size_t len)
 240 {
 241         ssize_t nr;
 242         if (len > MAX_IO_SIZE)
 243             len = MAX_IO_SIZE;
 244         while (1) {
 245                 nr = write(fd, buf, len);
 246                 if (nr < 0) {
 247                         if (errno == EINTR)
 248                                 continue;
 249                         if (handle_nonblock(fd, POLLOUT, errno))
 250                                 continue;
 251                 }
 252
 253                 return nr;
 254         }
 255 }
 256
 257 /*
 258  * xpread() is the same as pread(), but it automatically restarts pread()
 259  * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
 260  * NOT GUARANTEE that "len" bytes is read even if the data is available.
 261  */
 262 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
 263 {
 264         ssize_t nr;
 265         if (len > MAX_IO_SIZE)
 266                 len = MAX_IO_SIZE;
 267         while (1) {
 268                 nr = pread(fd, buf, len, offset);
 269                 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 270                         continue;
 271                 return nr;
 272         }
 273 }
 274
 275 ssize_t read_in_full(int fd, void *buf, size_t count)
 276 {
 277         char *p = buf;
 278         ssize_t total = 0;
 279
 280         while (count > 0) {
 281                 ssize_t loaded = xread(fd, p, count);
 282                 if (loaded < 0)
 283                         return -1;
 284                 if (loaded == 0)
 285                         return total;
 286                 count -= loaded;
 287                 p += loaded;
 288                 total += loaded;
 289         }
 290
 291         return total;
 292 }
 293
 294 ssize_t write_in_full(int fd, const void *buf, size_t count)
 295 {
 296         const char *p = buf;
 297         ssize_t total = 0;
 298
 299         while (count > 0) {
 300                 ssize_t written = xwrite(fd, p, count);
 301                 if (written < 0)
 302                         return -1;
 303                 if (!written) {
 304                         errno = ENOSPC;
 305                         return -1;
 306                 }
 307                 count -= written;
 308                 p += written;
 309                 total += written;
 310         }
 311
 312         return total;
 313 }
 314
 315 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
 316 {
 317         char *p = buf;
 318         ssize_t total = 0;
 319
 320         while (count > 0) {
 321                 ssize_t loaded = xpread(fd, p, count, offset);
 322                 if (loaded < 0)
 323                         return -1;
 324                 if (loaded == 0)
 325                         return total;
 326                 count -= loaded;
 327                 p += loaded;
 328                 total += loaded;
 329                 offset += loaded;
 330         }
 331
 332         return total;
 333 }
 334
 335 int xdup(int fd)
 336 {
 337         int ret = dup(fd);
 338         if (ret < 0)
 339                 die_errno("dup failed");
 340         return ret;
 341 }
 342
 343 /**
 344  * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
 345  */
 346 FILE *xfopen(const char *path, const char *mode)
 347 {
 348         for (;;) {
 349                 FILE *fp = fopen(path, mode);
 350                 if (fp)
 351                         return fp;
 352                 if (errno == EINTR)
 353                         continue;
 354
 355                 if (*mode && mode[1] == '+')
 356                         die_errno(_("could not open '%s' for reading and writing"), path);
 357                 else if (*mode == 'w' || *mode == 'a')
 358                         die_errno(_("could not open '%s' for writing"), path);
 359                 else
 360                         die_errno(_("could not open '%s' for reading"), path);
 361         }
 362 }
 363
 364 FILE *xfdopen(int fd, const char *mode)
 365 {
 366         FILE *stream = fdopen(fd, mode);
 367         if (stream == NULL)
 368                 die_errno("Out of memory? fdopen failed");
 369         return stream;
 370 }
 371
 372 FILE *fopen_for_writing(const char *path)
 373 {
 374         FILE *ret = fopen(path, "w");
 375
 376         if (!ret && errno == EPERM) {
 377                 if (!unlink(path))
 378                         ret = fopen(path, "w");
 379                 else
 380                         errno = EPERM;
 381         }
 382         return ret;
 383 }
 384
 385 static void warn_on_inaccessible(const char *path)
 386 {
 387         warning_errno(_("unable to access '%s'"), path);
 388 }
 389
 390 int warn_on_fopen_errors(const char *path)
 391 {
 392         if (errno != ENOENT && errno != ENOTDIR) {
 393                 warn_on_inaccessible(path);
 394                 return -1;
 395         }
 396
 397         return 0;
 398 }
 399
 400 FILE *fopen_or_warn(const char *path, const char *mode)
 401 {
 402         FILE *fp = fopen(path, mode);
 403
 404         if (fp)
 405                 return fp;
 406
 407         warn_on_fopen_errors(path);
 408         return NULL;
 409 }
 410
 411 int xmkstemp(char *filename_template)
 412 {
 413         int fd;
 414         char origtemplate[PATH_MAX];
 415         strlcpy(origtemplate, filename_template, sizeof(origtemplate));
 416
 417         fd = mkstemp(filename_template);
 418         if (fd < 0) {
 419                 int saved_errno = errno;
 420                 const char *nonrelative_template;
 421
 422                 if (strlen(filename_template) != strlen(origtemplate))
 423                         filename_template = origtemplate;
 424
 425                 nonrelative_template = absolute_path(filename_template);
 426                 errno = saved_errno;
 427                 die_errno("Unable to create temporary file '%s'",
 428                         nonrelative_template);
 429         }
 430         return fd;
 431 }
 432
 433 /* Adapted from libiberty's mkstemp.c. */
 434
 435 #undef TMP_MAX
 436 #define TMP_MAX 16384
 437
 438 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 439 {
 440         static const char letters[] =
 441                 "abcdefghijklmnopqrstuvwxyz"
 442                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 443                 "0123456789";
 444         static const int num_letters = 62;
 445         uint64_t value;
 446         struct timeval tv;
 447         char *filename_template;
 448         size_t len;
 449         int fd, count;
 450
 451         len = strlen(pattern);
 452
 453         if (len < 6 + suffix_len) {
 454                 errno = EINVAL;
 455                 return -1;
 456         }
 457
 458         if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 459                 errno = EINVAL;
 460                 return -1;
 461         }
 462
 463         /*
 464          * Replace pattern's XXXXXX characters with randomness.
 465          * Try TMP_MAX different filenames.
 466          */
 467         gettimeofday(&tv, NULL);
 468         value = ((uint64_t)tv.tv_usec << 16) ^ tv.tv_sec ^ getpid();
 469         filename_template = &pattern[len - 6 - suffix_len];
 470         for (count = 0; count < TMP_MAX; ++count) {
 471                 uint64_t v = value;
 472                 /* Fill in the random bits. */
 473                 filename_template[0] = letters[v % num_letters]; v /= num_letters;
 474                 filename_template[1] = letters[v % num_letters]; v /= num_letters;
 475                 filename_template[2] = letters[v % num_letters]; v /= num_letters;
 476                 filename_template[3] = letters[v % num_letters]; v /= num_letters;
 477                 filename_template[4] = letters[v % num_letters]; v /= num_letters;
 478                 filename_template[5] = letters[v % num_letters]; v /= num_letters;
 479
 480                 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 481                 if (fd >= 0)
 482                         return fd;
 483                 /*
 484                  * Fatal error (EPERM, ENOSPC etc).
 485                  * It doesn't make sense to loop.
 486                  */
 487                 if (errno != EEXIST)
 488                         break;
 489                 /*
 490                  * This is a random value.  It is only necessary that
 491                  * the next TMP_MAX values generated by adding 7777 to
 492                  * VALUE are different with (module 2^32).
 493                  */
 494                 value += 7777;
 495         }
 496         /* We return the null string if we can't find a unique file name.  */
 497         pattern[0] = '\0';
 498         return -1;
 499 }
 500
 501 int git_mkstemp_mode(char *pattern, int mode)
 502 {
 503         /* mkstemp is just mkstemps with no suffix */
 504         return git_mkstemps_mode(pattern, 0, mode);
 505 }
 506
 507 int xmkstemp_mode(char *filename_template, int mode)
 508 {
 509         int fd;
 510         char origtemplate[PATH_MAX];
 511         strlcpy(origtemplate, filename_template, sizeof(origtemplate));
 512
 513         fd = git_mkstemp_mode(filename_template, mode);
 514         if (fd < 0) {
 515                 int saved_errno = errno;
 516                 const char *nonrelative_template;
 517
 518                 if (!filename_template[0])
 519                         filename_template = origtemplate;
 520
 521                 nonrelative_template = absolute_path(filename_template);
 522                 errno = saved_errno;
 523                 die_errno("Unable to create temporary file '%s'",
 524                         nonrelative_template);
 525         }
 526         return fd;
 527 }
 528
 529 static int warn_if_unremovable(const char *op, const char *file, int rc)
 530 {
 531         int err;
 532         if (!rc || errno == ENOENT)
 533                 return 0;
 534         err = errno;
 535         warning_errno("unable to %s '%s'", op, file);
 536         errno = err;
 537         return rc;
 538 }
 539
 540 int unlink_or_msg(const char *file, struct strbuf *err)
 541 {
 542         int rc = unlink(file);
 543
 544         assert(err);
 545
 546         if (!rc || errno == ENOENT)
 547                 return 0;
 548
 549         strbuf_addf(err, "unable to unlink '%s': %s",
 550                     file, strerror(errno));
 551         return -1;
 552 }
 553
 554 int unlink_or_warn(const char *file)
 555 {
 556         return warn_if_unremovable("unlink", file, unlink(file));
 557 }
 558
 559 int rmdir_or_warn(const char *file)
 560 {
 561         return warn_if_unremovable("rmdir", file, rmdir(file));
 562 }
 563
 564 int remove_or_warn(unsigned int mode, const char *file)
 565 {
 566         return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 567 }
 568
 569 static int access_error_is_ok(int err, unsigned flag)
 570 {
 571         return (is_missing_file_error(err) ||
 572                 ((flag & ACCESS_EACCES_OK) && err == EACCES));
 573 }
 574
 575 int access_or_warn(const char *path, int mode, unsigned flag)
 576 {
 577         int ret = access(path, mode);
 578         if (ret && !access_error_is_ok(errno, flag))
 579                 warn_on_inaccessible(path);
 580         return ret;
 581 }
 582
 583 int access_or_die(const char *path, int mode, unsigned flag)
 584 {
 585         int ret = access(path, mode);
 586         if (ret && !access_error_is_ok(errno, flag))
 587                 die_errno(_("unable to access '%s'"), path);
 588         return ret;
 589 }
 590
 591 char *xgetcwd(void)
 592 {
 593         struct strbuf sb = STRBUF_INIT;
 594         if (strbuf_getcwd(&sb))
 595                 die_errno(_("unable to get current working directory"));
 596         return strbuf_detach(&sb, NULL);
 597 }
 598
 599 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
 600 {
 601         va_list ap;
 602         int len;
 603
 604         va_start(ap, fmt);
 605         len = vsnprintf(dst, max, fmt, ap);
 606         va_end(ap);
 607
 608         if (len < 0)
 609                 BUG("your snprintf is broken");
 610         if (len >= max)
 611                 BUG("attempt to snprintf into too-small buffer");
 612         return len;
 613 }
 614
 615 void write_file_buf(const char *path, const char *buf, size_t len)
 616 {
 617         int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 618         if (write_in_full(fd, buf, len) < 0)
 619                 die_errno(_("could not write to '%s'"), path);
 620         if (close(fd))
 621                 die_errno(_("could not close '%s'"), path);
 622 }
 623
 624 void write_file(const char *path, const char *fmt, ...)
 625 {
 626         va_list params;
 627         struct strbuf sb = STRBUF_INIT;
 628
 629         va_start(params, fmt);
 630         strbuf_vaddf(&sb, fmt, params);
 631         va_end(params);
 632
 633         strbuf_complete_line(&sb);
 634
 635         write_file_buf(path, sb.buf, sb.len);
 636         strbuf_release(&sb);
 637 }
 638
 639 void sleep_millisec(int millisec)
 640 {
 641         poll(NULL, 0, millisec);
 642 }
 643
 644 int xgethostname(char *buf, size_t len)
 645 {
 646         /*
 647          * If the full hostname doesn't fit in buf, POSIX does not
 648          * specify whether the buffer will be null-terminated, so to
 649          * be safe, do it ourselves.
 650          */
 651         int ret = gethostname(buf, len);
 652         if (!ret)
 653                 buf[len - 1] = 0;
 654         return ret;
 655 }
 656
 657 int is_empty_or_missing_file(const char *filename)
 658 {
 659         struct stat st;
 660
 661         if (stat(filename, &st) < 0) {
 662                 if (errno == ENOENT)
 663                         return 1;
 664                 die_errno(_("could not stat %s"), filename);
 665         }
 666
 667         return !st.st_size;
 668 }