| 1 | /* |
| 2 | * Various trivial helper wrappers around standard functions |
| 3 | */ |
| 4 | |
| 5 | #define DISABLE_SIGN_COMPARE_WARNINGS |
| 6 | |
| 7 | #include "git-compat-util.h" |
| 8 | #include "abspath.h" |
| 9 | #include "parse.h" |
| 10 | #include "gettext.h" |
| 11 | #include "strbuf.h" |
| 12 | #include "trace2.h" |
| 13 | |
| 14 | #ifdef HAVE_RTLGENRANDOM |
| 15 | /* This is required to get access to RtlGenRandom. */ |
| 16 | #define SystemFunction036 NTAPI SystemFunction036 |
| 17 | #include <ntsecapi.h> |
| 18 | #undef SystemFunction036 |
| 19 | #endif |
| 20 | |
| 21 | static int memory_limit_check(size_t size, int gentle) |
| 22 | { |
| 23 | static size_t limit = 0; |
| 24 | if (!limit) { |
| 25 | limit = git_env_ulong("GIT_ALLOC_LIMIT", 0); |
| 26 | if (!limit) |
| 27 | limit = SIZE_MAX; |
| 28 | } |
| 29 | if (size > limit) { |
| 30 | if (gentle) { |
| 31 | error("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX, |
| 32 | (uintmax_t)size, (uintmax_t)limit); |
| 33 | return -1; |
| 34 | } else |
| 35 | die("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX, |
| 36 | (uintmax_t)size, (uintmax_t)limit); |
| 37 | } |
| 38 | return 0; |
| 39 | } |
| 40 | |
| 41 | char *xstrdup(const char *str) |
| 42 | { |
| 43 | char *ret = strdup(str); |
| 44 | if (!ret) |
| 45 | die("Out of memory, strdup failed"); |
| 46 | return ret; |
| 47 | } |
| 48 | |
| 49 | static void *do_xmalloc(size_t size, int gentle) |
| 50 | { |
| 51 | void *ret; |
| 52 | |
| 53 | if (memory_limit_check(size, gentle)) |
| 54 | return NULL; |
| 55 | ret = malloc(size); |
| 56 | if (!ret && !size) |
| 57 | ret = malloc(1); |
| 58 | if (!ret) { |
| 59 | if (!gentle) |
| 60 | die("Out of memory, malloc failed (tried to allocate %lu bytes)", |
| 61 | (unsigned long)size); |
| 62 | else { |
| 63 | error("Out of memory, malloc failed (tried to allocate %lu bytes)", |
| 64 | (unsigned long)size); |
| 65 | return NULL; |
| 66 | } |
| 67 | } |
| 68 | #ifdef XMALLOC_POISON |
| 69 | memset(ret, 0xA5, size); |
| 70 | #endif |
| 71 | return ret; |
| 72 | } |
| 73 | |
| 74 | void *xmalloc(size_t size) |
| 75 | { |
| 76 | return do_xmalloc(size, 0); |
| 77 | } |
| 78 | |
| 79 | static void *do_xmallocz(size_t size, int gentle) |
| 80 | { |
| 81 | void *ret; |
| 82 | if (unsigned_add_overflows(size, 1)) { |
| 83 | if (gentle) { |
| 84 | error("Data too large to fit into virtual memory space."); |
| 85 | return NULL; |
| 86 | } else |
| 87 | die("Data too large to fit into virtual memory space."); |
| 88 | } |
| 89 | ret = do_xmalloc(size + 1, gentle); |
| 90 | if (ret) |
| 91 | ((char*)ret)[size] = 0; |
| 92 | return ret; |
| 93 | } |
| 94 | |
| 95 | void *xmallocz(size_t size) |
| 96 | { |
| 97 | return do_xmallocz(size, 0); |
| 98 | } |
| 99 | |
| 100 | void *xmallocz_gently(size_t size) |
| 101 | { |
| 102 | return do_xmallocz(size, 1); |
| 103 | } |
| 104 | |
| 105 | /* |
| 106 | * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of |
| 107 | * "data" to the allocated memory, zero terminates the allocated memory, |
| 108 | * and returns a pointer to the allocated memory. If the allocation fails, |
| 109 | * the program dies. |
| 110 | */ |
| 111 | void *xmemdupz(const void *data, size_t len) |
| 112 | { |
| 113 | return memcpy(xmallocz(len), data, len); |
| 114 | } |
| 115 | |
| 116 | char *xstrndup(const char *str, size_t len) |
| 117 | { |
| 118 | const char *p = memchr(str, '\0', len); |
| 119 | return xmemdupz(str, p ? p - str : len); |
| 120 | } |
| 121 | |
| 122 | int xstrncmpz(const char *s, const char *t, size_t len) |
| 123 | { |
| 124 | int res = strncmp(s, t, len); |
| 125 | if (res) |
| 126 | return res; |
| 127 | return s[len] == '\0' ? 0 : 1; |
| 128 | } |
| 129 | |
| 130 | void *xrealloc(void *ptr, size_t size) |
| 131 | { |
| 132 | void *ret; |
| 133 | |
| 134 | if (!size) { |
| 135 | free(ptr); |
| 136 | return xmalloc(0); |
| 137 | } |
| 138 | |
| 139 | memory_limit_check(size, 0); |
| 140 | ret = realloc(ptr, size); |
| 141 | if (!ret) |
| 142 | die("Out of memory, realloc failed"); |
| 143 | return ret; |
| 144 | } |
| 145 | |
| 146 | void *xcalloc(size_t nmemb, size_t size) |
| 147 | { |
| 148 | void *ret; |
| 149 | |
| 150 | if (unsigned_mult_overflows(nmemb, size)) |
| 151 | die("data too large to fit into virtual memory space"); |
| 152 | |
| 153 | memory_limit_check(size * nmemb, 0); |
| 154 | ret = calloc(nmemb, size); |
| 155 | if (!ret && (!nmemb || !size)) |
| 156 | ret = calloc(1, 1); |
| 157 | if (!ret) |
| 158 | die("Out of memory, calloc failed"); |
| 159 | return ret; |
| 160 | } |
| 161 | |
| 162 | void xsetenv(const char *name, const char *value, int overwrite) |
| 163 | { |
| 164 | if (setenv(name, value, overwrite)) |
| 165 | die_errno(_("could not setenv '%s'"), name ? name : "(null)"); |
| 166 | } |
| 167 | |
| 168 | /** |
| 169 | * xopen() is the same as open(), but it die()s if the open() fails. |
| 170 | */ |
| 171 | int xopen(const char *path, int oflag, ...) |
| 172 | { |
| 173 | mode_t mode = 0; |
| 174 | va_list ap; |
| 175 | |
| 176 | /* |
| 177 | * va_arg() will have undefined behavior if the specified type is not |
| 178 | * compatible with the argument type. Since integers are promoted to |
| 179 | * ints, we fetch the next argument as an int, and then cast it to a |
| 180 | * mode_t to avoid undefined behavior. |
| 181 | */ |
| 182 | va_start(ap, oflag); |
| 183 | if (oflag & O_CREAT) |
| 184 | mode = va_arg(ap, int); |
| 185 | va_end(ap); |
| 186 | |
| 187 | for (;;) { |
| 188 | int fd = open(path, oflag, mode); |
| 189 | if (fd >= 0) |
| 190 | return fd; |
| 191 | if (errno == EINTR) |
| 192 | continue; |
| 193 | |
| 194 | if ((oflag & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) |
| 195 | die_errno(_("unable to create '%s'"), path); |
| 196 | else if ((oflag & O_RDWR) == O_RDWR) |
| 197 | die_errno(_("could not open '%s' for reading and writing"), path); |
| 198 | else if ((oflag & O_WRONLY) == O_WRONLY) |
| 199 | die_errno(_("could not open '%s' for writing"), path); |
| 200 | else |
| 201 | die_errno(_("could not open '%s' for reading"), path); |
| 202 | } |
| 203 | } |
| 204 | |
| 205 | static int handle_nonblock(int fd, short poll_events, int err) |
| 206 | { |
| 207 | struct pollfd pfd; |
| 208 | |
| 209 | if (err != EAGAIN && err != EWOULDBLOCK) |
| 210 | return 0; |
| 211 | |
| 212 | pfd.fd = fd; |
| 213 | pfd.events = poll_events; |
| 214 | |
| 215 | /* |
| 216 | * no need to check for errors, here; |
| 217 | * a subsequent read/write will detect unrecoverable errors |
| 218 | */ |
| 219 | poll(&pfd, 1, -1); |
| 220 | return 1; |
| 221 | } |
| 222 | |
| 223 | /* |
| 224 | * xread() is the same a read(), but it automatically restarts read() |
| 225 | * operations with a recoverable error (EAGAIN and EINTR). xread() |
| 226 | * DOES NOT GUARANTEE that "len" bytes is read even if the data is available. |
| 227 | */ |
| 228 | ssize_t xread(int fd, void *buf, size_t len) |
| 229 | { |
| 230 | ssize_t nr; |
| 231 | if (len > MAX_IO_SIZE) |
| 232 | len = MAX_IO_SIZE; |
| 233 | while (1) { |
| 234 | nr = read(fd, buf, len); |
| 235 | if (nr < 0) { |
| 236 | if (errno == EINTR) |
| 237 | continue; |
| 238 | if (handle_nonblock(fd, POLLIN, errno)) |
| 239 | continue; |
| 240 | } |
| 241 | return nr; |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | /* |
| 246 | * xwrite() is the same a write(), but it automatically restarts write() |
| 247 | * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT |
| 248 | * GUARANTEE that "len" bytes is written even if the operation is successful. |
| 249 | */ |
| 250 | ssize_t xwrite(int fd, const void *buf, size_t len) |
| 251 | { |
| 252 | ssize_t nr; |
| 253 | if (len > MAX_IO_SIZE) |
| 254 | len = MAX_IO_SIZE; |
| 255 | while (1) { |
| 256 | nr = write(fd, buf, len); |
| 257 | if (nr < 0) { |
| 258 | if (errno == EINTR) |
| 259 | continue; |
| 260 | if (handle_nonblock(fd, POLLOUT, errno)) |
| 261 | continue; |
| 262 | } |
| 263 | |
| 264 | return nr; |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | /* |
| 269 | * xpread() is the same as pread(), but it automatically restarts pread() |
| 270 | * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES |
| 271 | * NOT GUARANTEE that "len" bytes is read even if the data is available. |
| 272 | */ |
| 273 | ssize_t xpread(int fd, void *buf, size_t len, off_t offset) |
| 274 | { |
| 275 | ssize_t nr; |
| 276 | if (len > MAX_IO_SIZE) |
| 277 | len = MAX_IO_SIZE; |
| 278 | while (1) { |
| 279 | nr = pread(fd, buf, len, offset); |
| 280 | if ((nr < 0) && (errno == EAGAIN || errno == EINTR)) |
| 281 | continue; |
| 282 | return nr; |
| 283 | } |
| 284 | } |
| 285 | |
| 286 | ssize_t read_in_full(int fd, void *buf, size_t count) |
| 287 | { |
| 288 | char *p = buf; |
| 289 | ssize_t total = 0; |
| 290 | |
| 291 | while (count > 0) { |
| 292 | ssize_t loaded = xread(fd, p, count); |
| 293 | if (loaded < 0) |
| 294 | return -1; |
| 295 | if (loaded == 0) |
| 296 | return total; |
| 297 | count -= loaded; |
| 298 | p += loaded; |
| 299 | total += loaded; |
| 300 | } |
| 301 | |
| 302 | return total; |
| 303 | } |
| 304 | |
| 305 | ssize_t write_in_full(int fd, const void *buf, size_t count) |
| 306 | { |
| 307 | const char *p = buf; |
| 308 | ssize_t total = 0; |
| 309 | |
| 310 | while (count > 0) { |
| 311 | ssize_t written = xwrite(fd, p, count); |
| 312 | if (written < 0) |
| 313 | return -1; |
| 314 | if (!written) { |
| 315 | errno = ENOSPC; |
| 316 | return -1; |
| 317 | } |
| 318 | count -= written; |
| 319 | p += written; |
| 320 | total += written; |
| 321 | } |
| 322 | |
| 323 | return total; |
| 324 | } |
| 325 | |
| 326 | ssize_t xwritev(int fd, struct iovec *iov, int iovcnt) |
| 327 | { |
| 328 | size_t allowed = MAX_IO_SIZE; |
| 329 | int i; |
| 330 | |
| 331 | /* |
| 332 | * Some platforms define a comparatively small `MAX_IO_SIZE` that |
| 333 | * limits how many bytes can be written with a single call to |
| 334 | * write(3p) or writev(3p); exceeding that limit causes the syscall to |
| 335 | * fail with EINVAL. Just like xwrite() chomps overly large requests |
| 336 | * for write(3p), pretend that the underlying writev(3p) performed a |
| 337 | * short write by only passing along the leading iovec entries that |
| 338 | * fit into that limit. |
| 339 | */ |
| 340 | for (i = 0; i < iovcnt; i++) { |
| 341 | if (iov[i].iov_len > allowed) { |
| 342 | /* |
| 343 | * If the first buffer is larger than MAX_IO_SIZE, |
| 344 | * let xwrite() deal with it. |
| 345 | */ |
| 346 | if (!i) |
| 347 | return xwrite(fd, iov->iov_base, iov->iov_len); |
| 348 | break; |
| 349 | } |
| 350 | allowed -= iov[i].iov_len; |
| 351 | } |
| 352 | |
| 353 | while (1) { |
| 354 | ssize_t bytes_written = writev(fd, iov, i); |
| 355 | if (bytes_written < 0) { |
| 356 | if (errno == EINTR) |
| 357 | continue; |
| 358 | if (handle_nonblock(fd, POLLOUT, errno)) |
| 359 | continue; |
| 360 | } |
| 361 | |
| 362 | return bytes_written; |
| 363 | } |
| 364 | } |
| 365 | |
| 366 | ssize_t writev_in_full(int fd, struct iovec *iov, int iovcnt) |
| 367 | { |
| 368 | ssize_t total_written = 0; |
| 369 | |
| 370 | while (iovcnt) { |
| 371 | ssize_t bytes_written = xwritev(fd, iov, iovcnt); |
| 372 | if (bytes_written < 0) |
| 373 | return -1; |
| 374 | if (!bytes_written) { |
| 375 | errno = ENOSPC; |
| 376 | return -1; |
| 377 | } |
| 378 | |
| 379 | total_written += bytes_written; |
| 380 | |
| 381 | /* |
| 382 | * We first need to discard any iovec entities that have been |
| 383 | * fully written. |
| 384 | */ |
| 385 | while (iovcnt && (size_t)bytes_written >= iov->iov_len) { |
| 386 | bytes_written -= iov->iov_len; |
| 387 | iov++; |
| 388 | iovcnt--; |
| 389 | } |
| 390 | |
| 391 | /* |
| 392 | * Finally, we need to adjust the last iovec in case we have |
| 393 | * performed a partial write. |
| 394 | */ |
| 395 | if (iovcnt && bytes_written) { |
| 396 | iov->iov_base = (char *) iov->iov_base + bytes_written; |
| 397 | iov->iov_len -= bytes_written; |
| 398 | } |
| 399 | } |
| 400 | |
| 401 | return total_written; |
| 402 | } |
| 403 | |
| 404 | ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset) |
| 405 | { |
| 406 | char *p = buf; |
| 407 | ssize_t total = 0; |
| 408 | |
| 409 | while (count > 0) { |
| 410 | ssize_t loaded = xpread(fd, p, count, offset); |
| 411 | if (loaded < 0) |
| 412 | return -1; |
| 413 | if (loaded == 0) |
| 414 | return total; |
| 415 | count -= loaded; |
| 416 | p += loaded; |
| 417 | total += loaded; |
| 418 | offset += loaded; |
| 419 | } |
| 420 | |
| 421 | return total; |
| 422 | } |
| 423 | |
| 424 | int xdup(int fd) |
| 425 | { |
| 426 | int ret = dup(fd); |
| 427 | if (ret < 0) |
| 428 | die_errno("dup failed"); |
| 429 | return ret; |
| 430 | } |
| 431 | |
| 432 | /** |
| 433 | * xfopen() is the same as fopen(), but it die()s if the fopen() fails. |
| 434 | */ |
| 435 | FILE *xfopen(const char *path, const char *mode) |
| 436 | { |
| 437 | for (;;) { |
| 438 | FILE *fp = fopen(path, mode); |
| 439 | if (fp) |
| 440 | return fp; |
| 441 | if (errno == EINTR) |
| 442 | continue; |
| 443 | |
| 444 | if (*mode && mode[1] == '+') |
| 445 | die_errno(_("could not open '%s' for reading and writing"), path); |
| 446 | else if (*mode == 'w' || *mode == 'a') |
| 447 | die_errno(_("could not open '%s' for writing"), path); |
| 448 | else |
| 449 | die_errno(_("could not open '%s' for reading"), path); |
| 450 | } |
| 451 | } |
| 452 | |
| 453 | FILE *xfdopen(int fd, const char *mode) |
| 454 | { |
| 455 | FILE *stream = fdopen(fd, mode); |
| 456 | if (!stream) |
| 457 | die_errno("Out of memory? fdopen failed"); |
| 458 | return stream; |
| 459 | } |
| 460 | |
| 461 | FILE *fopen_for_writing(const char *path) |
| 462 | { |
| 463 | FILE *ret = fopen(path, "w"); |
| 464 | |
| 465 | if (!ret && errno == EPERM) { |
| 466 | if (!unlink(path)) |
| 467 | ret = fopen(path, "w"); |
| 468 | else |
| 469 | errno = EPERM; |
| 470 | } |
| 471 | return ret; |
| 472 | } |
| 473 | |
| 474 | static void warn_on_inaccessible(const char *path) |
| 475 | { |
| 476 | warning_errno(_("unable to access '%s'"), path); |
| 477 | } |
| 478 | |
| 479 | int warn_on_fopen_errors(const char *path) |
| 480 | { |
| 481 | if (errno != ENOENT && errno != ENOTDIR) { |
| 482 | warn_on_inaccessible(path); |
| 483 | return -1; |
| 484 | } |
| 485 | |
| 486 | return 0; |
| 487 | } |
| 488 | |
| 489 | FILE *fopen_or_warn(const char *path, const char *mode) |
| 490 | { |
| 491 | FILE *fp = fopen(path, mode); |
| 492 | |
| 493 | if (fp) |
| 494 | return fp; |
| 495 | |
| 496 | warn_on_fopen_errors(path); |
| 497 | return NULL; |
| 498 | } |
| 499 | |
| 500 | int xmkstemp(char *filename_template) |
| 501 | { |
| 502 | return xmkstemp_mode(filename_template, 0600); |
| 503 | } |
| 504 | |
| 505 | /* Adapted from libiberty's mkstemp.c. */ |
| 506 | |
| 507 | #undef TMP_MAX |
| 508 | #define TMP_MAX 16384 |
| 509 | |
| 510 | /* |
| 511 | * Returns -1 on error, 0 if it created a directory, or an open file |
| 512 | * descriptor to the created regular file. |
| 513 | */ |
| 514 | static int git_mkdstemps_mode(char *pattern, int suffix_len, int mode, bool dir) |
| 515 | { |
| 516 | static const char letters[] = |
| 517 | "abcdefghijklmnopqrstuvwxyz" |
| 518 | "ABCDEFGHIJKLMNOPQRSTUVWXYZ" |
| 519 | "0123456789"; |
| 520 | static const int num_letters = ARRAY_SIZE(letters) - 1; |
| 521 | static const char x_pattern[] = "XXXXXX"; |
| 522 | static const int num_x = ARRAY_SIZE(x_pattern) - 1; |
| 523 | char *filename_template; |
| 524 | size_t len; |
| 525 | int fd, count; |
| 526 | |
| 527 | len = strlen(pattern); |
| 528 | |
| 529 | if (len < num_x + suffix_len) { |
| 530 | errno = EINVAL; |
| 531 | return -1; |
| 532 | } |
| 533 | |
| 534 | if (strncmp(&pattern[len - num_x - suffix_len], x_pattern, num_x)) { |
| 535 | errno = EINVAL; |
| 536 | return -1; |
| 537 | } |
| 538 | |
| 539 | /* |
| 540 | * Replace pattern's XXXXXX characters with randomness. |
| 541 | * Try TMP_MAX different filenames. |
| 542 | */ |
| 543 | filename_template = &pattern[len - num_x - suffix_len]; |
| 544 | for (count = 0; count < TMP_MAX; ++count) { |
| 545 | int i; |
| 546 | uint64_t v; |
| 547 | if (csprng_bytes(&v, sizeof(v), 0) < 0) |
| 548 | return error_errno("unable to get random bytes for temporary file"); |
| 549 | |
| 550 | /* Fill in the random bits. */ |
| 551 | for (i = 0; i < num_x; i++) { |
| 552 | filename_template[i] = letters[v % num_letters]; |
| 553 | v /= num_letters; |
| 554 | } |
| 555 | |
| 556 | if (dir) |
| 557 | fd = mkdir(pattern, mode); |
| 558 | else |
| 559 | fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode); |
| 560 | if (fd >= 0) |
| 561 | return fd; |
| 562 | /* |
| 563 | * Fatal error (EPERM, ENOSPC etc). |
| 564 | * It doesn't make sense to loop. |
| 565 | */ |
| 566 | if (errno != EEXIST) |
| 567 | break; |
| 568 | } |
| 569 | /* We return the null string if we can't find a unique file name. */ |
| 570 | pattern[0] = '\0'; |
| 571 | return -1; |
| 572 | } |
| 573 | |
| 574 | char *git_mkdtemp(char *pattern) |
| 575 | { |
| 576 | return git_mkdstemps_mode(pattern, 0, 0700, true) ? NULL : pattern; |
| 577 | } |
| 578 | |
| 579 | int git_mkstemps_mode(char *pattern, int suffix_len, int mode) |
| 580 | { |
| 581 | return git_mkdstemps_mode(pattern, suffix_len, mode, false); |
| 582 | } |
| 583 | |
| 584 | int git_mkstemp_mode(char *pattern, int mode) |
| 585 | { |
| 586 | /* mkstemp is just mkstemps with no suffix */ |
| 587 | return git_mkstemps_mode(pattern, 0, mode); |
| 588 | } |
| 589 | |
| 590 | int xmkstemp_mode(char *filename_template, int mode) |
| 591 | { |
| 592 | int fd; |
| 593 | char origtemplate[PATH_MAX]; |
| 594 | strlcpy(origtemplate, filename_template, sizeof(origtemplate)); |
| 595 | |
| 596 | fd = git_mkstemp_mode(filename_template, mode); |
| 597 | if (fd < 0) { |
| 598 | int saved_errno = errno; |
| 599 | const char *nonrelative_template; |
| 600 | |
| 601 | if (!filename_template[0]) |
| 602 | filename_template = origtemplate; |
| 603 | |
| 604 | nonrelative_template = absolute_path(filename_template); |
| 605 | errno = saved_errno; |
| 606 | die_errno("Unable to create temporary file '%s'", |
| 607 | nonrelative_template); |
| 608 | } |
| 609 | return fd; |
| 610 | } |
| 611 | |
| 612 | /* |
| 613 | * Some platforms return EINTR from fsync. Since fsync is invoked in some |
| 614 | * cases by a wrapper that dies on failure, do not expose EINTR to callers. |
| 615 | */ |
| 616 | static int fsync_loop(int fd) |
| 617 | { |
| 618 | int err; |
| 619 | |
| 620 | do { |
| 621 | err = fsync(fd); |
| 622 | } while (err < 0 && errno == EINTR); |
| 623 | return err; |
| 624 | } |
| 625 | |
| 626 | int git_fsync(int fd, enum fsync_action action) |
| 627 | { |
| 628 | switch (action) { |
| 629 | case FSYNC_WRITEOUT_ONLY: |
| 630 | trace2_counter_add(TRACE2_COUNTER_ID_FSYNC_WRITEOUT_ONLY, 1); |
| 631 | |
| 632 | #ifdef __APPLE__ |
| 633 | /* |
| 634 | * On macOS, fsync just causes filesystem cache writeback but |
| 635 | * does not flush hardware caches. |
| 636 | */ |
| 637 | return fsync_loop(fd); |
| 638 | #endif |
| 639 | |
| 640 | #ifdef HAVE_SYNC_FILE_RANGE |
| 641 | /* |
| 642 | * On linux 2.6.17 and above, sync_file_range is the way to |
| 643 | * issue a writeback without a hardware flush. An offset of |
| 644 | * 0 and size of 0 indicates writeout of the entire file and the |
| 645 | * wait flags ensure that all dirty data is written to the disk |
| 646 | * (potentially in a disk-side cache) before we continue. |
| 647 | */ |
| 648 | |
| 649 | return sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WAIT_BEFORE | |
| 650 | SYNC_FILE_RANGE_WRITE | |
| 651 | SYNC_FILE_RANGE_WAIT_AFTER); |
| 652 | #endif |
| 653 | |
| 654 | #ifdef fsync_no_flush |
| 655 | return fsync_no_flush(fd); |
| 656 | #endif |
| 657 | |
| 658 | errno = ENOSYS; |
| 659 | return -1; |
| 660 | |
| 661 | case FSYNC_HARDWARE_FLUSH: |
| 662 | trace2_counter_add(TRACE2_COUNTER_ID_FSYNC_HARDWARE_FLUSH, 1); |
| 663 | |
| 664 | /* |
| 665 | * On macOS, a special fcntl is required to really flush the |
| 666 | * caches within the storage controller. As of this writing, |
| 667 | * this is a very expensive operation on Apple SSDs. |
| 668 | */ |
| 669 | #ifdef __APPLE__ |
| 670 | return fcntl(fd, F_FULLFSYNC); |
| 671 | #else |
| 672 | return fsync_loop(fd); |
| 673 | #endif |
| 674 | default: |
| 675 | BUG("unexpected git_fsync(%d) call", action); |
| 676 | } |
| 677 | } |
| 678 | |
| 679 | static int warn_if_unremovable(const char *op, const char *file, int rc) |
| 680 | { |
| 681 | int err; |
| 682 | if (!rc || errno == ENOENT) |
| 683 | return 0; |
| 684 | err = errno; |
| 685 | warning_errno("unable to %s '%s'", op, file); |
| 686 | errno = err; |
| 687 | return rc; |
| 688 | } |
| 689 | |
| 690 | int unlink_or_msg(const char *file, struct strbuf *err) |
| 691 | { |
| 692 | int rc = unlink(file); |
| 693 | |
| 694 | assert(err); |
| 695 | |
| 696 | if (!rc || errno == ENOENT) |
| 697 | return 0; |
| 698 | |
| 699 | strbuf_addf(err, "unable to unlink '%s': %s", |
| 700 | file, strerror(errno)); |
| 701 | return -1; |
| 702 | } |
| 703 | |
| 704 | int unlink_or_warn(const char *file) |
| 705 | { |
| 706 | return warn_if_unremovable("unlink", file, unlink(file)); |
| 707 | } |
| 708 | |
| 709 | int rmdir_or_warn(const char *file) |
| 710 | { |
| 711 | return warn_if_unremovable("rmdir", file, rmdir(file)); |
| 712 | } |
| 713 | |
| 714 | static int access_error_is_ok(int err, unsigned flag) |
| 715 | { |
| 716 | return (is_missing_file_error(err) || |
| 717 | ((flag & ACCESS_EACCES_OK) && err == EACCES)); |
| 718 | } |
| 719 | |
| 720 | int access_or_warn(const char *path, int mode, unsigned flag) |
| 721 | { |
| 722 | int ret = access(path, mode); |
| 723 | if (ret && !access_error_is_ok(errno, flag)) |
| 724 | warn_on_inaccessible(path); |
| 725 | return ret; |
| 726 | } |
| 727 | |
| 728 | int access_or_die(const char *path, int mode, unsigned flag) |
| 729 | { |
| 730 | int ret = access(path, mode); |
| 731 | if (ret && !access_error_is_ok(errno, flag)) |
| 732 | die_errno(_("unable to access '%s'"), path); |
| 733 | return ret; |
| 734 | } |
| 735 | |
| 736 | char *xgetcwd(void) |
| 737 | { |
| 738 | struct strbuf sb = STRBUF_INIT; |
| 739 | if (strbuf_getcwd(&sb)) |
| 740 | die_errno(_("unable to get current working directory")); |
| 741 | return strbuf_detach(&sb, NULL); |
| 742 | } |
| 743 | |
| 744 | int xsnprintf(char *dst, size_t max, const char *fmt, ...) |
| 745 | { |
| 746 | va_list ap; |
| 747 | int len; |
| 748 | |
| 749 | va_start(ap, fmt); |
| 750 | len = vsnprintf(dst, max, fmt, ap); |
| 751 | va_end(ap); |
| 752 | |
| 753 | if (len < 0) |
| 754 | die(_("unable to format message: %s"), fmt); |
| 755 | if (len >= max) |
| 756 | BUG("attempt to snprintf into too-small buffer"); |
| 757 | return len; |
| 758 | } |
| 759 | |
| 760 | void write_file_buf(const char *path, const char *buf, size_t len) |
| 761 | { |
| 762 | int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666); |
| 763 | if (write_in_full(fd, buf, len) < 0) |
| 764 | die_errno(_("could not write to '%s'"), path); |
| 765 | if (close(fd)) |
| 766 | die_errno(_("could not close '%s'"), path); |
| 767 | } |
| 768 | |
| 769 | void write_file(const char *path, const char *fmt, ...) |
| 770 | { |
| 771 | va_list params; |
| 772 | struct strbuf sb = STRBUF_INIT; |
| 773 | |
| 774 | va_start(params, fmt); |
| 775 | strbuf_vaddf(&sb, fmt, params); |
| 776 | va_end(params); |
| 777 | |
| 778 | strbuf_complete_line(&sb); |
| 779 | |
| 780 | write_file_buf(path, sb.buf, sb.len); |
| 781 | strbuf_release(&sb); |
| 782 | } |
| 783 | |
| 784 | void sleep_millisec(int millisec) |
| 785 | { |
| 786 | poll(NULL, 0, millisec); |
| 787 | } |
| 788 | |
| 789 | int xgethostname(char *buf, size_t len) |
| 790 | { |
| 791 | /* |
| 792 | * If the full hostname doesn't fit in buf, POSIX does not |
| 793 | * specify whether the buffer will be null-terminated, so to |
| 794 | * be safe, do it ourselves. |
| 795 | */ |
| 796 | int ret = gethostname(buf, len); |
| 797 | if (!ret) |
| 798 | buf[len - 1] = 0; |
| 799 | return ret; |
| 800 | } |
| 801 | |
| 802 | int is_missing_file(const char *filename) |
| 803 | { |
| 804 | struct stat st; |
| 805 | |
| 806 | if (stat(filename, &st) < 0) { |
| 807 | if (errno == ENOENT) |
| 808 | return 1; |
| 809 | die_errno(_("could not stat %s"), filename); |
| 810 | } |
| 811 | |
| 812 | return 0; |
| 813 | } |
| 814 | |
| 815 | int is_empty_or_missing_file(const char *filename) |
| 816 | { |
| 817 | struct stat st; |
| 818 | |
| 819 | if (stat(filename, &st) < 0) { |
| 820 | if (errno == ENOENT) |
| 821 | return 1; |
| 822 | die_errno(_("could not stat %s"), filename); |
| 823 | } |
| 824 | |
| 825 | return !st.st_size; |
| 826 | } |
| 827 | |
| 828 | int open_nofollow(const char *path, int flags) |
| 829 | { |
| 830 | #ifdef O_NOFOLLOW |
| 831 | int ret = open(path, flags | O_NOFOLLOW); |
| 832 | /* |
| 833 | * NetBSD sets errno to EFTYPE when path is a symlink. The only other |
| 834 | * time this errno occurs when O_REGULAR is used. Since we don't use |
| 835 | * it anywhere we can avoid an lstat here. FreeBSD does the same with |
| 836 | * EMLINK. |
| 837 | */ |
| 838 | # ifdef __NetBSD__ |
| 839 | # define SYMLINK_ERRNO EFTYPE |
| 840 | # elif defined(__FreeBSD__) |
| 841 | # define SYMLINK_ERRNO EMLINK |
| 842 | # endif |
| 843 | # if SYMLINK_ERRNO |
| 844 | if (ret < 0 && errno == SYMLINK_ERRNO) { |
| 845 | errno = ELOOP; |
| 846 | return -1; |
| 847 | } |
| 848 | # undef SYMLINK_ERRNO |
| 849 | # endif |
| 850 | return ret; |
| 851 | #else |
| 852 | struct stat st; |
| 853 | if (lstat(path, &st) < 0) |
| 854 | return -1; |
| 855 | if (S_ISLNK(st.st_mode)) { |
| 856 | errno = ELOOP; |
| 857 | return -1; |
| 858 | } |
| 859 | return open(path, flags); |
| 860 | #endif |
| 861 | } |
| 862 | |
| 863 | int csprng_bytes(void *buf, size_t len, MAYBE_UNUSED unsigned flags) |
| 864 | { |
| 865 | #if defined(HAVE_ARC4RANDOM) || defined(HAVE_ARC4RANDOM_LIBBSD) |
| 866 | /* This function never returns an error. */ |
| 867 | arc4random_buf(buf, len); |
| 868 | return 0; |
| 869 | #elif defined(HAVE_GETRANDOM) |
| 870 | ssize_t res; |
| 871 | char *p = buf; |
| 872 | while (len) { |
| 873 | res = getrandom(p, len, 0); |
| 874 | if (res < 0) |
| 875 | return -1; |
| 876 | len -= res; |
| 877 | p += res; |
| 878 | } |
| 879 | return 0; |
| 880 | #elif defined(HAVE_GETENTROPY) |
| 881 | int res; |
| 882 | char *p = buf; |
| 883 | while (len) { |
| 884 | /* getentropy has a maximum size of 256 bytes. */ |
| 885 | size_t chunk = len < 256 ? len : 256; |
| 886 | res = getentropy(p, chunk); |
| 887 | if (res < 0) |
| 888 | return -1; |
| 889 | len -= chunk; |
| 890 | p += chunk; |
| 891 | } |
| 892 | return 0; |
| 893 | #elif defined(HAVE_RTLGENRANDOM) |
| 894 | if (!RtlGenRandom(buf, len)) |
| 895 | return -1; |
| 896 | return 0; |
| 897 | #elif defined(HAVE_OPENSSL_CSPRNG) |
| 898 | switch (RAND_pseudo_bytes(buf, len)) { |
| 899 | case 1: |
| 900 | return 0; |
| 901 | case 0: |
| 902 | if (flags & CSPRNG_BYTES_INSECURE) |
| 903 | return 0; |
| 904 | errno = EIO; |
| 905 | return -1; |
| 906 | default: |
| 907 | errno = ENOTSUP; |
| 908 | return -1; |
| 909 | } |
| 910 | #else |
| 911 | ssize_t res; |
| 912 | char *p = buf; |
| 913 | int fd, err; |
| 914 | fd = open("/dev/urandom", O_RDONLY); |
| 915 | if (fd < 0) |
| 916 | return -1; |
| 917 | while (len) { |
| 918 | res = xread(fd, p, len); |
| 919 | if (res < 0) { |
| 920 | err = errno; |
| 921 | close(fd); |
| 922 | errno = err; |
| 923 | return -1; |
| 924 | } |
| 925 | len -= res; |
| 926 | p += res; |
| 927 | } |
| 928 | close(fd); |
| 929 | return 0; |
| 930 | #endif |
| 931 | } |
| 932 | |
| 933 | uint32_t git_rand(unsigned flags) |
| 934 | { |
| 935 | uint32_t result; |
| 936 | |
| 937 | if (csprng_bytes(&result, sizeof(result), flags) < 0) |
| 938 | die(_("unable to get random bytes")); |
| 939 | |
| 940 | return result; |
| 941 | } |
| 942 | |
| 943 | static void mmap_limit_check(size_t length) |
| 944 | { |
| 945 | static size_t limit = 0; |
| 946 | if (!limit) { |
| 947 | limit = git_env_ulong("GIT_MMAP_LIMIT", 0); |
| 948 | if (!limit) |
| 949 | limit = SIZE_MAX; |
| 950 | } |
| 951 | if (length > limit) |
| 952 | die(_("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX), |
| 953 | (uintmax_t)length, (uintmax_t)limit); |
| 954 | } |
| 955 | |
| 956 | void *xmmap_gently(void *start, size_t length, |
| 957 | int prot, int flags, int fd, off_t offset) |
| 958 | { |
| 959 | void *ret; |
| 960 | |
| 961 | mmap_limit_check(length); |
| 962 | ret = mmap(start, length, prot, flags, fd, offset); |
| 963 | if (ret == MAP_FAILED && !length) |
| 964 | ret = NULL; |
| 965 | return ret; |
| 966 | } |
| 967 | |
| 968 | const char *mmap_os_err(void) |
| 969 | { |
| 970 | static const char blank[] = ""; |
| 971 | #if defined(__linux__) |
| 972 | if (errno == ENOMEM) { |
| 973 | /* this continues an existing error message: */ |
| 974 | static const char enomem[] = |
| 975 | ", check sys.vm.max_map_count and/or RLIMIT_DATA"; |
| 976 | return enomem; |
| 977 | } |
| 978 | #endif /* OS-specific bits */ |
| 979 | return blank; |
| 980 | } |
| 981 | |
| 982 | void *xmmap(void *start, size_t length, |
| 983 | int prot, int flags, int fd, off_t offset) |
| 984 | { |
| 985 | void *ret = xmmap_gently(start, length, prot, flags, fd, offset); |
| 986 | if (ret == MAP_FAILED) |
| 987 | die_errno(_("mmap failed%s"), mmap_os_err()); |
| 988 | return ret; |
| 989 | } |