git-compat-util.h

   1 #ifndef GIT_COMPAT_UTIL_H
   2 #define GIT_COMPAT_UTIL_H
   3
   4 #if __STDC_VERSION__ - 0 < 199901L
   5 /*
   6  * Git is in a testing period for mandatory C99 support in the compiler.  If
   7  * your compiler is reasonably recent, you can try to enable C99 support (or,
   8  * for MSVC, C11 support).  If you encounter a problem and can't enable C99
   9  * support with your compiler (such as with "-std=gnu99") and don't have access
  10  * to one with this support, such as GCC or Clang, you can remove this #if
  11  * directive, but please report the details of your system to
  12  * git@vger.kernel.org.
  13  */
  14 #error "Required C99 support is in a test phase.  Please see git-compat-util.h for more details."
  15 #endif
  16
  17 #ifdef USE_MSVC_CRTDBG
  18 /*
  19  * For these to work they must appear very early in each
  20  * file -- before most of the standard header files.
  21  */
  22 #include <stdlib.h>
  23 #include <crtdbg.h>
  24 #endif
  25
  26 #define _FILE_OFFSET_BITS 64
  27
  28
  29 /* Derived from Linux "Features Test Macro" header
  30  * Convenience macros to test the versions of gcc (or
  31  * a compatible compiler).
  32  * Use them like this:
  33  *  #if GIT_GNUC_PREREQ (2,8)
  34  *   ... code requiring gcc 2.8 or later ...
  35  *  #endif
  36 */
  37 #if defined(__GNUC__) && defined(__GNUC_MINOR__)
  38 # define GIT_GNUC_PREREQ(maj, min) \
  39         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
  40 #else
  41  #define GIT_GNUC_PREREQ(maj, min) 0
  42 #endif
  43
  44
  45 #ifndef FLEX_ARRAY
  46 /*
  47  * See if our compiler is known to support flexible array members.
  48  */
  49
  50 /*
  51  * Check vendor specific quirks first, before checking the
  52  * __STDC_VERSION__, as vendor compilers can lie and we need to be
  53  * able to work them around.  Note that by not defining FLEX_ARRAY
  54  * here, we can fall back to use the "safer but a bit wasteful" one
  55  * later.
  56  */
  57 #if defined(__SUNPRO_C) && (__SUNPRO_C <= 0x580)
  58 #elif defined(__GNUC__)
  59 # if (__GNUC__ >= 3)
  60 #  define FLEX_ARRAY /* empty */
  61 # else
  62 #  define FLEX_ARRAY 0 /* older GNU extension */
  63 # endif
  64 #elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
  65 # define FLEX_ARRAY /* empty */
  66 #endif
  67
  68 /*
  69  * Otherwise, default to safer but a bit wasteful traditional style
  70  */
  71 #ifndef FLEX_ARRAY
  72 # define FLEX_ARRAY 1
  73 #endif
  74 #endif
  75
  76
  77 /*
  78  * BUILD_ASSERT_OR_ZERO - assert a build-time dependency, as an expression.
  79  * @cond: the compile-time condition which must be true.
  80  *
  81  * Your compile will fail if the condition isn't true, or can't be evaluated
  82  * by the compiler.  This can be used in an expression: its value is "0".
  83  *
  84  * Example:
  85  *      #define foo_to_char(foo)                                        \
  86  *               ((char *)(foo)                                         \
  87  *                + BUILD_ASSERT_OR_ZERO(offsetof(struct foo, string) == 0))
  88  */
  89 #define BUILD_ASSERT_OR_ZERO(cond) \
  90         (sizeof(char [1 - 2*!(cond)]) - 1)
  91
  92 #if GIT_GNUC_PREREQ(3, 1)
  93  /* &arr[0] degrades to a pointer: a different type from an array */
  94 # define BARF_UNLESS_AN_ARRAY(arr)                                              \
  95         BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(__typeof__(arr), \
  96                                                            __typeof__(&(arr)[0])))
  97 #else
  98 # define BARF_UNLESS_AN_ARRAY(arr) 0
  99 #endif
 100 /*
 101  * ARRAY_SIZE - get the number of elements in a visible array
 102  * @x: the array whose size you want.
 103  *
 104  * This does not work on pointers, or arrays declared as [], or
 105  * function parameters.  With correct compiler support, such usage
 106  * will cause a build error (see the build_assert_or_zero macro).
 107  */
 108 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + BARF_UNLESS_AN_ARRAY(x))
 109
 110 #define bitsizeof(x)  (CHAR_BIT * sizeof(x))
 111
 112 #define maximum_signed_value_of_type(a) \
 113     (INTMAX_MAX >> (bitsizeof(intmax_t) - bitsizeof(a)))
 114
 115 #define maximum_unsigned_value_of_type(a) \
 116     (UINTMAX_MAX >> (bitsizeof(uintmax_t) - bitsizeof(a)))
 117
 118 /*
 119  * Signed integer overflow is undefined in C, so here's a helper macro
 120  * to detect if the sum of two integers will overflow.
 121  *
 122  * Requires: a >= 0, typeof(a) equals typeof(b)
 123  */
 124 #define signed_add_overflows(a, b) \
 125     ((b) > maximum_signed_value_of_type(a) - (a))
 126
 127 #define unsigned_add_overflows(a, b) \
 128     ((b) > maximum_unsigned_value_of_type(a) - (a))
 129
 130 /*
 131  * Returns true if the multiplication of "a" and "b" will
 132  * overflow. The types of "a" and "b" must match and must be unsigned.
 133  * Note that this macro evaluates "a" twice!
 134  */
 135 #define unsigned_mult_overflows(a, b) \
 136     ((a) && (b) > maximum_unsigned_value_of_type(a) / (a))
 137
 138 /*
 139  * Returns true if the left shift of "a" by "shift" bits will
 140  * overflow. The type of "a" must be unsigned.
 141  */
 142 #define unsigned_left_shift_overflows(a, shift) \
 143     ((shift) < bitsizeof(a) && \
 144      (a) > maximum_unsigned_value_of_type(a) >> (shift))
 145
 146 #ifdef __GNUC__
 147 #define TYPEOF(x) (__typeof__(x))
 148 #else
 149 #define TYPEOF(x)
 150 #endif
 151
 152 #define MSB(x, bits) ((x) & TYPEOF(x)(~0ULL << (bitsizeof(x) - (bits))))
 153 #define HAS_MULTI_BITS(i)  ((i) & ((i) - 1))  /* checks if an integer has more than 1 bit set */
 154
 155 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
 156
 157 /* Approximation of the length of the decimal representation of this type. */
 158 #define decimal_length(x)       ((int)(sizeof(x) * 2.56 + 0.5) + 1)
 159
 160 #ifdef __MINGW64__
 161 #define _POSIX_C_SOURCE 1
 162 #elif defined(__sun__)
 163  /*
 164   * On Solaris, when _XOPEN_EXTENDED is set, its header file
 165   * forces the programs to be XPG4v2, defeating any _XOPEN_SOURCE
 166   * setting to say we are XPG5 or XPG6.  Also on Solaris,
 167   * XPG6 programs must be compiled with a c99 compiler, while
 168   * non XPG6 programs must be compiled with a pre-c99 compiler.
 169   */
 170 # if __STDC_VERSION__ - 0 >= 199901L
 171 # define _XOPEN_SOURCE 600
 172 # else
 173 # define _XOPEN_SOURCE 500
 174 # endif
 175 #elif !defined(__APPLE__) && !defined(__FreeBSD__) && !defined(__USLC__) && \
 176       !defined(_M_UNIX) && !defined(__sgi) && !defined(__DragonFly__) && \
 177       !defined(__TANDEM) && !defined(__QNX__) && !defined(__MirBSD__) && \
 178       !defined(__CYGWIN__)
 179 #define _XOPEN_SOURCE 600 /* glibc2 and AIX 5.3L need 500, OpenBSD needs 600 for S_ISLNK() */
 180 #define _XOPEN_SOURCE_EXTENDED 1 /* AIX 5.3L needs this */
 181 #endif
 182 #define _ALL_SOURCE 1
 183 #define _GNU_SOURCE 1
 184 #define _BSD_SOURCE 1
 185 #define _DEFAULT_SOURCE 1
 186 #define _NETBSD_SOURCE 1
 187 #define _SGI_SOURCE 1
 188
 189 #if defined(WIN32) && !defined(__CYGWIN__) /* Both MinGW and MSVC */
 190 # if !defined(_WIN32_WINNT)
 191 #  define _WIN32_WINNT 0x0600
 192 # endif
 193 #define WIN32_LEAN_AND_MEAN  /* stops windows.h including winsock.h */
 194 #include <winsock2.h>
 195 #ifndef NO_UNIX_SOCKETS
 196 #include <afunix.h>
 197 #endif
 198 #include <windows.h>
 199 #define GIT_WINDOWS_NATIVE
 200 #endif
 201
 202 #include <unistd.h>
 203 #include <stdio.h>
 204 #include <sys/stat.h>
 205 #include <fcntl.h>
 206 #include <stddef.h>
 207 #include <stdlib.h>
 208 #include <stdarg.h>
 209 #include <string.h>
 210 #ifdef HAVE_STRINGS_H
 211 #include <strings.h> /* for strcasecmp() */
 212 #endif
 213 #include <errno.h>
 214 #include <limits.h>
 215 #ifdef NEEDS_SYS_PARAM_H
 216 #include <sys/param.h>
 217 #endif
 218 #include <sys/types.h>
 219 #include <dirent.h>
 220 #include <sys/time.h>
 221 #include <time.h>
 222 #include <signal.h>
 223 #include <assert.h>
 224 #include <regex.h>
 225 #include <utime.h>
 226 #include <syslog.h>
 227 #if !defined(NO_POLL_H)
 228 #include <poll.h>
 229 #elif !defined(NO_SYS_POLL_H)
 230 #include <sys/poll.h>
 231 #else
 232 /* Pull the compat stuff */
 233 #include <poll.h>
 234 #endif
 235 #ifdef HAVE_BSD_SYSCTL
 236 #include <sys/sysctl.h>
 237 #endif
 238
 239 /* Used by compat/win32/path-utils.h, and more */
 240 static inline int is_xplatform_dir_sep(int c)
 241 {
 242         return c == '/' || c == '\\';
 243 }
 244
 245 #if defined(__CYGWIN__)
 246 #include "compat/win32/path-utils.h"
 247 #endif
 248 #if defined(__MINGW32__)
 249 /* pull in Windows compatibility stuff */
 250 #include "compat/win32/path-utils.h"
 251 #include "compat/mingw.h"
 252 #elif defined(_MSC_VER)
 253 #include "compat/win32/path-utils.h"
 254 #include "compat/msvc.h"
 255 #else
 256 #include <sys/utsname.h>
 257 #include <sys/wait.h>
 258 #include <sys/resource.h>
 259 #include <sys/socket.h>
 260 #include <sys/ioctl.h>
 261 #include <termios.h>
 262 #ifndef NO_SYS_SELECT_H
 263 #include <sys/select.h>
 264 #endif
 265 #include <netinet/in.h>
 266 #include <netinet/tcp.h>
 267 #include <arpa/inet.h>
 268 #include <netdb.h>
 269 #include <pwd.h>
 270 #include <sys/un.h>
 271 #ifndef NO_INTTYPES_H
 272 #include <inttypes.h>
 273 #else
 274 #include <stdint.h>
 275 #endif
 276 #ifdef HAVE_ARC4RANDOM_LIBBSD
 277 #include <bsd/stdlib.h>
 278 #endif
 279 #ifdef HAVE_GETRANDOM
 280 #include <sys/random.h>
 281 #endif
 282 #ifdef NO_INTPTR_T
 283 /*
 284  * On I16LP32, ILP32 and LP64 "long" is the safe bet, however
 285  * on LLP86, IL33LLP64 and P64 it needs to be "long long",
 286  * while on IP16 and IP16L32 it is "int" (resp. "short")
 287  * Size needs to match (or exceed) 'sizeof(void *)'.
 288  * We can't take "long long" here as not everybody has it.
 289  */
 290 typedef long intptr_t;
 291 typedef unsigned long uintptr_t;
 292 #endif
 293 #undef _ALL_SOURCE /* AIX 5.3L defines a struct list with _ALL_SOURCE. */
 294 #include <grp.h>
 295 #define _ALL_SOURCE 1
 296 #endif
 297
 298 /* used on Mac OS X */
 299 #ifdef PRECOMPOSE_UNICODE
 300 #include "compat/precompose_utf8.h"
 301 #else
 302 static inline const char *precompose_argv_prefix(int argc, const char **argv, const char *prefix)
 303 {
 304         return prefix;
 305 }
 306 static inline const char *precompose_string_if_needed(const char *in)
 307 {
 308         return in;
 309 }
 310
 311 #define probe_utf8_pathname_composition()
 312 #endif
 313
 314 #ifdef MKDIR_WO_TRAILING_SLASH
 315 #define mkdir(a,b) compat_mkdir_wo_trailing_slash((a),(b))
 316 int compat_mkdir_wo_trailing_slash(const char*, mode_t);
 317 #endif
 318
 319 #ifdef NO_STRUCT_ITIMERVAL
 320 struct itimerval {
 321         struct timeval it_interval;
 322         struct timeval it_value;
 323 };
 324 #endif
 325
 326 #ifdef NO_SETITIMER
 327 static inline int setitimer(int which, const struct itimerval *value, struct itimerval *newvalue) {
 328         return 0; /* pretend success */
 329 }
 330 #endif
 331
 332 #ifndef NO_LIBGEN_H
 333 #include <libgen.h>
 334 #else
 335 #define basename gitbasename
 336 char *gitbasename(char *);
 337 #define dirname gitdirname
 338 char *gitdirname(char *);
 339 #endif
 340
 341 #ifndef NO_ICONV
 342 #include <iconv.h>
 343 #endif
 344
 345 #ifndef NO_OPENSSL
 346 #ifdef __APPLE__
 347 #define __AVAILABILITY_MACROS_USES_AVAILABILITY 0
 348 #include <AvailabilityMacros.h>
 349 #undef DEPRECATED_ATTRIBUTE
 350 #define DEPRECATED_ATTRIBUTE
 351 #undef __AVAILABILITY_MACROS_USES_AVAILABILITY
 352 #endif
 353 #include <openssl/ssl.h>
 354 #include <openssl/err.h>
 355 #endif
 356
 357 #ifdef HAVE_SYSINFO
 358 # include <sys/sysinfo.h>
 359 #endif
 360
 361 /* On most systems <netdb.h> would have given us this, but
 362  * not on some systems (e.g. z/OS).
 363  */
 364 #ifndef NI_MAXHOST
 365 #define NI_MAXHOST 1025
 366 #endif
 367
 368 #ifndef NI_MAXSERV
 369 #define NI_MAXSERV 32
 370 #endif
 371
 372 /* On most systems <limits.h> would have given us this, but
 373  * not on some systems (e.g. GNU/Hurd).
 374  */
 375 #ifndef PATH_MAX
 376 #define PATH_MAX 4096
 377 #endif
 378
 379 typedef uintmax_t timestamp_t;
 380 #define PRItime PRIuMAX
 381 #define parse_timestamp strtoumax
 382 #define TIME_MAX UINTMAX_MAX
 383 #define TIME_MIN 0
 384
 385 #ifndef PATH_SEP
 386 #define PATH_SEP ':'
 387 #endif
 388
 389 #ifdef HAVE_PATHS_H
 390 #include <paths.h>
 391 #endif
 392 #ifndef _PATH_DEFPATH
 393 #define _PATH_DEFPATH "/usr/local/bin:/usr/bin:/bin"
 394 #endif
 395
 396 #ifndef platform_core_config
 397 static inline int noop_core_config(const char *var, const char *value, void *cb)
 398 {
 399         return 0;
 400 }
 401 #define platform_core_config noop_core_config
 402 #endif
 403
 404 int lstat_cache_aware_rmdir(const char *path);
 405 #if !defined(__MINGW32__) && !defined(_MSC_VER)
 406 #define rmdir lstat_cache_aware_rmdir
 407 #endif
 408
 409 #ifndef has_dos_drive_prefix
 410 static inline int git_has_dos_drive_prefix(const char *path)
 411 {
 412         return 0;
 413 }
 414 #define has_dos_drive_prefix git_has_dos_drive_prefix
 415 #endif
 416
 417 #ifndef skip_dos_drive_prefix
 418 static inline int git_skip_dos_drive_prefix(char **path)
 419 {
 420         return 0;
 421 }
 422 #define skip_dos_drive_prefix git_skip_dos_drive_prefix
 423 #endif
 424
 425 static inline int git_is_dir_sep(int c)
 426 {
 427         return c == '/';
 428 }
 429 #ifndef is_dir_sep
 430 #define is_dir_sep git_is_dir_sep
 431 #endif
 432
 433 #ifndef offset_1st_component
 434 static inline int git_offset_1st_component(const char *path)
 435 {
 436         return is_dir_sep(path[0]);
 437 }
 438 #define offset_1st_component git_offset_1st_component
 439 #endif
 440
 441 #ifndef is_valid_path
 442 #define is_valid_path(path) 1
 443 #endif
 444
 445 #ifndef is_path_owned_by_current_user
 446
 447 #ifdef __TANDEM
 448 #define ROOT_UID 65535
 449 #else
 450 #define ROOT_UID 0
 451 #endif
 452
 453 /*
 454  * Do not use this function when
 455  * (1) geteuid() did not say we are running as 'root', or
 456  * (2) using this function will compromise the system.
 457  *
 458  * PORTABILITY WARNING:
 459  * This code assumes uid_t is unsigned because that is what sudo does.
 460  * If your uid_t type is signed and all your ids are positive then it
 461  * should all work fine.
 462  * If your version of sudo uses negative values for uid_t or it is
 463  * buggy and return an overflowed value in SUDO_UID, then git might
 464  * fail to grant access to your repository properly or even mistakenly
 465  * grant access to someone else.
 466  * In the unlikely scenario this happened to you, and that is how you
 467  * got to this message, we would like to know about it; so sent us an
 468  * email to git@vger.kernel.org indicating which platform you are
 469  * using and which version of sudo, so we can improve this logic and
 470  * maybe provide you with a patch that would prevent this issue again
 471  * in the future.
 472  */
 473 static inline void extract_id_from_env(const char *env, uid_t *id)
 474 {
 475         const char *real_uid = getenv(env);
 476
 477         /* discard anything empty to avoid a more complex check below */
 478         if (real_uid && *real_uid) {
 479                 char *endptr = NULL;
 480                 unsigned long env_id;
 481
 482                 errno = 0;
 483                 /* silent overflow errors could trigger a bug here */
 484                 env_id = strtoul(real_uid, &endptr, 10);
 485                 if (!*endptr && !errno)
 486                         *id = env_id;
 487         }
 488 }
 489
 490 static inline int is_path_owned_by_current_uid(const char *path)
 491 {
 492         struct stat st;
 493         uid_t euid;
 494
 495         if (lstat(path, &st))
 496                 return 0;
 497
 498         euid = geteuid();
 499         if (euid == ROOT_UID)
 500                 extract_id_from_env("SUDO_UID", &euid);
 501
 502         return st.st_uid == euid;
 503 }
 504
 505 #define is_path_owned_by_current_user is_path_owned_by_current_uid
 506 #endif
 507
 508 #ifndef find_last_dir_sep
 509 static inline char *git_find_last_dir_sep(const char *path)
 510 {
 511         return strrchr(path, '/');
 512 }
 513 #define find_last_dir_sep git_find_last_dir_sep
 514 #endif
 515
 516 #ifndef has_dir_sep
 517 static inline int git_has_dir_sep(const char *path)
 518 {
 519         return !!strchr(path, '/');
 520 }
 521 #define has_dir_sep(path) git_has_dir_sep(path)
 522 #endif
 523
 524 #ifndef query_user_email
 525 #define query_user_email() NULL
 526 #endif
 527
 528 #ifdef __TANDEM
 529 #include <floss.h(floss_execl,floss_execlp,floss_execv,floss_execvp)>
 530 #include <floss.h(floss_getpwuid)>
 531 #ifndef NSIG
 532 /*
 533  * NonStop NSE and NSX do not provide NSIG. SIGGUARDIAN(99) is the highest
 534  * known, by detective work using kill -l as a list is all signals
 535  * instead of signal.h where it should be.
 536  */
 537 # define NSIG 100
 538 #endif
 539 #endif
 540
 541 #if defined(__HP_cc) && (__HP_cc >= 61000)
 542 #define NORETURN __attribute__((noreturn))
 543 #define NORETURN_PTR
 544 #elif defined(__GNUC__) && !defined(NO_NORETURN)
 545 #define NORETURN __attribute__((__noreturn__))
 546 #define NORETURN_PTR __attribute__((__noreturn__))
 547 #elif defined(_MSC_VER)
 548 #define NORETURN __declspec(noreturn)
 549 #define NORETURN_PTR
 550 #else
 551 #define NORETURN
 552 #define NORETURN_PTR
 553 #ifndef __GNUC__
 554 #ifndef __attribute__
 555 #define __attribute__(x)
 556 #endif
 557 #endif
 558 #endif
 559
 560 /* The sentinel attribute is valid from gcc version 4.0 */
 561 #if defined(__GNUC__) && (__GNUC__ >= 4)
 562 #define LAST_ARG_MUST_BE_NULL __attribute__((sentinel))
 563 #else
 564 #define LAST_ARG_MUST_BE_NULL
 565 #endif
 566
 567 #define MAYBE_UNUSED __attribute__((__unused__))
 568
 569 #include "compat/bswap.h"
 570
 571 #include "wildmatch.h"
 572
 573 struct strbuf;
 574
 575 /* General helper functions */
 576 NORETURN void usage(const char *err);
 577 NORETURN void usagef(const char *err, ...) __attribute__((format (printf, 1, 2)));
 578 NORETURN void die(const char *err, ...) __attribute__((format (printf, 1, 2)));
 579 NORETURN void die_errno(const char *err, ...) __attribute__((format (printf, 1, 2)));
 580 int die_message(const char *err, ...) __attribute__((format (printf, 1, 2)));
 581 int die_message_errno(const char *err, ...) __attribute__((format (printf, 1, 2)));
 582 int error(const char *err, ...) __attribute__((format (printf, 1, 2)));
 583 int error_errno(const char *err, ...) __attribute__((format (printf, 1, 2)));
 584 void warning(const char *err, ...) __attribute__((format (printf, 1, 2)));
 585 void warning_errno(const char *err, ...) __attribute__((format (printf, 1, 2)));
 586
 587 #ifndef NO_OPENSSL
 588 #ifdef APPLE_COMMON_CRYPTO
 589 #include "compat/apple-common-crypto.h"
 590 #else
 591 #include <openssl/evp.h>
 592 #include <openssl/hmac.h>
 593 #endif /* APPLE_COMMON_CRYPTO */
 594 #include <openssl/x509v3.h>
 595 #endif /* NO_OPENSSL */
 596
 597 #ifdef HAVE_OPENSSL_CSPRNG
 598 #include <openssl/rand.h>
 599 #endif
 600
 601 /*
 602  * Let callers be aware of the constant return value; this can help
 603  * gcc with -Wuninitialized analysis. We restrict this trick to gcc, though,
 604  * because other compilers may be confused by this.
 605  */
 606 #if defined(__GNUC__)
 607 static inline int const_error(void)
 608 {
 609         return -1;
 610 }
 611 #define error(...) (error(__VA_ARGS__), const_error())
 612 #define error_errno(...) (error_errno(__VA_ARGS__), const_error())
 613 #endif
 614
 615 typedef void (*report_fn)(const char *, va_list params);
 616
 617 void set_die_routine(NORETURN_PTR report_fn routine);
 618 report_fn get_die_message_routine(void);
 619 void set_error_routine(report_fn routine);
 620 report_fn get_error_routine(void);
 621 void set_warn_routine(report_fn routine);
 622 report_fn get_warn_routine(void);
 623 void set_die_is_recursing_routine(int (*routine)(void));
 624
 625 int starts_with(const char *str, const char *prefix);
 626 int istarts_with(const char *str, const char *prefix);
 627
 628 /*
 629  * If the string "str" begins with the string found in "prefix", return 1.
 630  * The "out" parameter is set to "str + strlen(prefix)" (i.e., to the point in
 631  * the string right after the prefix).
 632  *
 633  * Otherwise, return 0 and leave "out" untouched.
 634  *
 635  * Examples:
 636  *
 637  *   [extract branch name, fail if not a branch]
 638  *   if (!skip_prefix(ref, "refs/heads/", &branch)
 639  *      return -1;
 640  *
 641  *   [skip prefix if present, otherwise use whole string]
 642  *   skip_prefix(name, "refs/heads/", &name);
 643  */
 644 static inline int skip_prefix(const char *str, const char *prefix,
 645                               const char **out)
 646 {
 647         do {
 648                 if (!*prefix) {
 649                         *out = str;
 650                         return 1;
 651                 }
 652         } while (*str++ == *prefix++);
 653         return 0;
 654 }
 655
 656 /*
 657  * If the string "str" is the same as the string in "prefix", then the "arg"
 658  * parameter is set to the "def" parameter and 1 is returned.
 659  * If the string "str" begins with the string found in "prefix" and then a
 660  * "=" sign, then the "arg" parameter is set to "str + strlen(prefix) + 1"
 661  * (i.e., to the point in the string right after the prefix and the "=" sign),
 662  * and 1 is returned.
 663  *
 664  * Otherwise, return 0 and leave "arg" untouched.
 665  *
 666  * When we accept both a "--key" and a "--key=<val>" option, this function
 667  * can be used instead of !strcmp(arg, "--key") and then
 668  * skip_prefix(arg, "--key=", &arg) to parse such an option.
 669  */
 670 int skip_to_optional_arg_default(const char *str, const char *prefix,
 671                                  const char **arg, const char *def);
 672
 673 static inline int skip_to_optional_arg(const char *str, const char *prefix,
 674                                        const char **arg)
 675 {
 676         return skip_to_optional_arg_default(str, prefix, arg, "");
 677 }
 678
 679 /*
 680  * Like skip_prefix, but promises never to read past "len" bytes of the input
 681  * buffer, and returns the remaining number of bytes in "out" via "outlen".
 682  */
 683 static inline int skip_prefix_mem(const char *buf, size_t len,
 684                                   const char *prefix,
 685                                   const char **out, size_t *outlen)
 686 {
 687         size_t prefix_len = strlen(prefix);
 688         if (prefix_len <= len && !memcmp(buf, prefix, prefix_len)) {
 689                 *out = buf + prefix_len;
 690                 *outlen = len - prefix_len;
 691                 return 1;
 692         }
 693         return 0;
 694 }
 695
 696 /*
 697  * If buf ends with suffix, return 1 and subtract the length of the suffix
 698  * from *len. Otherwise, return 0 and leave *len untouched.
 699  */
 700 static inline int strip_suffix_mem(const char *buf, size_t *len,
 701                                    const char *suffix)
 702 {
 703         size_t suflen = strlen(suffix);
 704         if (*len < suflen || memcmp(buf + (*len - suflen), suffix, suflen))
 705                 return 0;
 706         *len -= suflen;
 707         return 1;
 708 }
 709
 710 /*
 711  * If str ends with suffix, return 1 and set *len to the size of the string
 712  * without the suffix. Otherwise, return 0 and set *len to the size of the
 713  * string.
 714  *
 715  * Note that we do _not_ NUL-terminate str to the new length.
 716  */
 717 static inline int strip_suffix(const char *str, const char *suffix, size_t *len)
 718 {
 719         *len = strlen(str);
 720         return strip_suffix_mem(str, len, suffix);
 721 }
 722
 723 static inline int ends_with(const char *str, const char *suffix)
 724 {
 725         size_t len;
 726         return strip_suffix(str, suffix, &len);
 727 }
 728
 729 #define SWAP(a, b) do {                                         \
 730         void *_swap_a_ptr = &(a);                               \
 731         void *_swap_b_ptr = &(b);                               \
 732         unsigned char _swap_buffer[sizeof(a)];                  \
 733         memcpy(_swap_buffer, _swap_a_ptr, sizeof(a));           \
 734         memcpy(_swap_a_ptr, _swap_b_ptr, sizeof(a) +            \
 735                BUILD_ASSERT_OR_ZERO(sizeof(a) == sizeof(b)));   \
 736         memcpy(_swap_b_ptr, _swap_buffer, sizeof(a));           \
 737 } while (0)
 738
 739 #if defined(NO_MMAP) || defined(USE_WIN32_MMAP)
 740
 741 #ifndef PROT_READ
 742 #define PROT_READ 1
 743 #define PROT_WRITE 2
 744 #define MAP_PRIVATE 1
 745 #endif
 746
 747 #define mmap git_mmap
 748 #define munmap git_munmap
 749 void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
 750 int git_munmap(void *start, size_t length);
 751
 752 #else /* NO_MMAP || USE_WIN32_MMAP */
 753
 754 #include <sys/mman.h>
 755
 756 #endif /* NO_MMAP || USE_WIN32_MMAP */
 757
 758 #ifdef NO_MMAP
 759
 760 /* This value must be multiple of (pagesize * 2) */
 761 #define DEFAULT_PACKED_GIT_WINDOW_SIZE (1 * 1024 * 1024)
 762
 763 #else /* NO_MMAP */
 764
 765 /* This value must be multiple of (pagesize * 2) */
 766 #define DEFAULT_PACKED_GIT_WINDOW_SIZE \
 767         (sizeof(void*) >= 8 \
 768                 ?  1 * 1024 * 1024 * 1024 \
 769                 : 32 * 1024 * 1024)
 770
 771 #endif /* NO_MMAP */
 772
 773 #ifndef MAP_FAILED
 774 #define MAP_FAILED ((void *)-1)
 775 #endif
 776
 777 #ifdef NO_ST_BLOCKS_IN_STRUCT_STAT
 778 #define on_disk_bytes(st) ((st).st_size)
 779 #else
 780 #define on_disk_bytes(st) ((st).st_blocks * 512)
 781 #endif
 782
 783 #ifdef NEEDS_MODE_TRANSLATION
 784 #undef S_IFMT
 785 #undef S_IFREG
 786 #undef S_IFDIR
 787 #undef S_IFLNK
 788 #undef S_IFBLK
 789 #undef S_IFCHR
 790 #undef S_IFIFO
 791 #undef S_IFSOCK
 792 #define S_IFMT   0170000
 793 #define S_IFREG  0100000
 794 #define S_IFDIR  0040000
 795 #define S_IFLNK  0120000
 796 #define S_IFBLK  0060000
 797 #define S_IFCHR  0020000
 798 #define S_IFIFO  0010000
 799 #define S_IFSOCK 0140000
 800 #ifdef stat
 801 #undef stat
 802 #endif
 803 #define stat(path, buf) git_stat(path, buf)
 804 int git_stat(const char *, struct stat *);
 805 #ifdef fstat
 806 #undef fstat
 807 #endif
 808 #define fstat(fd, buf) git_fstat(fd, buf)
 809 int git_fstat(int, struct stat *);
 810 #ifdef lstat
 811 #undef lstat
 812 #endif
 813 #define lstat(path, buf) git_lstat(path, buf)
 814 int git_lstat(const char *, struct stat *);
 815 #endif
 816
 817 #define DEFAULT_PACKED_GIT_LIMIT \
 818         ((1024L * 1024L) * (size_t)(sizeof(void*) >= 8 ? (32 * 1024L * 1024L) : 256))
 819
 820 #ifdef NO_PREAD
 821 #define pread git_pread
 822 ssize_t git_pread(int fd, void *buf, size_t count, off_t offset);
 823 #endif
 824 /*
 825  * Forward decl that will remind us if its twin in cache.h changes.
 826  * This function is used in compat/pread.c.  But we can't include
 827  * cache.h there.
 828  */
 829 ssize_t read_in_full(int fd, void *buf, size_t count);
 830
 831 #ifdef NO_SETENV
 832 #define setenv gitsetenv
 833 int gitsetenv(const char *, const char *, int);
 834 #endif
 835
 836 #ifdef NO_MKDTEMP
 837 #define mkdtemp gitmkdtemp
 838 char *gitmkdtemp(char *);
 839 #endif
 840
 841 #ifdef NO_UNSETENV
 842 #define unsetenv gitunsetenv
 843 int gitunsetenv(const char *);
 844 #endif
 845
 846 #ifdef NO_STRCASESTR
 847 #define strcasestr gitstrcasestr
 848 char *gitstrcasestr(const char *haystack, const char *needle);
 849 #endif
 850
 851 #ifdef NO_STRLCPY
 852 #define strlcpy gitstrlcpy
 853 size_t gitstrlcpy(char *, const char *, size_t);
 854 #endif
 855
 856 #ifdef NO_STRTOUMAX
 857 #define strtoumax gitstrtoumax
 858 uintmax_t gitstrtoumax(const char *, char **, int);
 859 #define strtoimax gitstrtoimax
 860 intmax_t gitstrtoimax(const char *, char **, int);
 861 #endif
 862
 863 #ifdef NO_HSTRERROR
 864 #define hstrerror githstrerror
 865 const char *githstrerror(int herror);
 866 #endif
 867
 868 #ifdef NO_MEMMEM
 869 #define memmem gitmemmem
 870 void *gitmemmem(const void *haystack, size_t haystacklen,
 871                 const void *needle, size_t needlelen);
 872 #endif
 873
 874 #ifdef OVERRIDE_STRDUP
 875 #ifdef strdup
 876 #undef strdup
 877 #endif
 878 #define strdup gitstrdup
 879 char *gitstrdup(const char *s);
 880 #endif
 881
 882 #ifdef NO_GETPAGESIZE
 883 #define getpagesize() sysconf(_SC_PAGESIZE)
 884 #endif
 885
 886 #ifndef O_CLOEXEC
 887 #define O_CLOEXEC 0
 888 #endif
 889
 890 #ifdef FREAD_READS_DIRECTORIES
 891 # if !defined(SUPPRESS_FOPEN_REDEFINITION)
 892 #  ifdef fopen
 893 #   undef fopen
 894 #  endif
 895 #  define fopen(a,b) git_fopen(a,b)
 896 # endif
 897 FILE *git_fopen(const char*, const char*);
 898 #endif
 899
 900 #ifdef SNPRINTF_RETURNS_BOGUS
 901 #ifdef snprintf
 902 #undef snprintf
 903 #endif
 904 #define snprintf git_snprintf
 905 int git_snprintf(char *str, size_t maxsize,
 906                  const char *format, ...);
 907 #ifdef vsnprintf
 908 #undef vsnprintf
 909 #endif
 910 #define vsnprintf git_vsnprintf
 911 int git_vsnprintf(char *str, size_t maxsize,
 912                   const char *format, va_list ap);
 913 #endif
 914
 915 #ifdef OPEN_RETURNS_EINTR
 916 #undef open
 917 #define open git_open_with_retry
 918 int git_open_with_retry(const char *path, int flag, ...);
 919 #endif
 920
 921 #ifdef __GLIBC_PREREQ
 922 #if __GLIBC_PREREQ(2, 1)
 923 #define HAVE_STRCHRNUL
 924 #endif
 925 #endif
 926
 927 #ifndef HAVE_STRCHRNUL
 928 #define strchrnul gitstrchrnul
 929 static inline char *gitstrchrnul(const char *s, int c)
 930 {
 931         while (*s && *s != c)
 932                 s++;
 933         return (char *)s;
 934 }
 935 #endif
 936
 937 #ifdef NO_INET_PTON
 938 int inet_pton(int af, const char *src, void *dst);
 939 #endif
 940
 941 #ifdef NO_INET_NTOP
 942 const char *inet_ntop(int af, const void *src, char *dst, size_t size);
 943 #endif
 944
 945 #ifdef NO_PTHREADS
 946 #define atexit git_atexit
 947 int git_atexit(void (*handler)(void));
 948 #endif
 949
 950 static inline size_t st_add(size_t a, size_t b)
 951 {
 952         if (unsigned_add_overflows(a, b))
 953                 die("size_t overflow: %"PRIuMAX" + %"PRIuMAX,
 954                     (uintmax_t)a, (uintmax_t)b);
 955         return a + b;
 956 }
 957 #define st_add3(a,b,c)   st_add(st_add((a),(b)),(c))
 958 #define st_add4(a,b,c,d) st_add(st_add3((a),(b),(c)),(d))
 959
 960 static inline size_t st_mult(size_t a, size_t b)
 961 {
 962         if (unsigned_mult_overflows(a, b))
 963                 die("size_t overflow: %"PRIuMAX" * %"PRIuMAX,
 964                     (uintmax_t)a, (uintmax_t)b);
 965         return a * b;
 966 }
 967
 968 static inline size_t st_sub(size_t a, size_t b)
 969 {
 970         if (a < b)
 971                 die("size_t underflow: %"PRIuMAX" - %"PRIuMAX,
 972                     (uintmax_t)a, (uintmax_t)b);
 973         return a - b;
 974 }
 975
 976 static inline size_t st_left_shift(size_t a, unsigned shift)
 977 {
 978         if (unsigned_left_shift_overflows(a, shift))
 979                 die("size_t overflow: %"PRIuMAX" << %u",
 980                     (uintmax_t)a, shift);
 981         return a << shift;
 982 }
 983
 984 static inline unsigned long cast_size_t_to_ulong(size_t a)
 985 {
 986         if (a != (unsigned long)a)
 987                 die("object too large to read on this platform: %"
 988                     PRIuMAX" is cut off to %lu",
 989                     (uintmax_t)a, (unsigned long)a);
 990         return (unsigned long)a;
 991 }
 992
 993 #ifdef HAVE_ALLOCA_H
 994 # include <alloca.h>
 995 # define xalloca(size)      (alloca(size))
 996 # define xalloca_free(p)    do {} while (0)
 997 #else
 998 # define xalloca(size)      (xmalloc(size))
 999 # define xalloca_free(p)    (free(p))
1000 #endif
1001 char *xstrdup(const char *str);
1002 void *xmalloc(size_t size);
1003 void *xmallocz(size_t size);
1004 void *xmallocz_gently(size_t size);
1005 void *xmemdupz(const void *data, size_t len);
1006 char *xstrndup(const char *str, size_t len);
1007 void *xrealloc(void *ptr, size_t size);
1008 void *xcalloc(size_t nmemb, size_t size);
1009 void xsetenv(const char *name, const char *value, int overwrite);
1010 void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
1011 const char *mmap_os_err(void);
1012 void *xmmap_gently(void *start, size_t length, int prot, int flags, int fd, off_t offset);
1013 int xopen(const char *path, int flags, ...);
1014 ssize_t xread(int fd, void *buf, size_t len);
1015 ssize_t xwrite(int fd, const void *buf, size_t len);
1016 ssize_t xpread(int fd, void *buf, size_t len, off_t offset);
1017 int xdup(int fd);
1018 FILE *xfopen(const char *path, const char *mode);
1019 FILE *xfdopen(int fd, const char *mode);
1020 int xmkstemp(char *temp_filename);
1021 int xmkstemp_mode(char *temp_filename, int mode);
1022 char *xgetcwd(void);
1023 FILE *fopen_for_writing(const char *path);
1024 FILE *fopen_or_warn(const char *path, const char *mode);
1025
1026 /*
1027  * Like strncmp, but only return zero if s is NUL-terminated and exactly len
1028  * characters long.  If it is not, consider it greater than t.
1029  */
1030 int xstrncmpz(const char *s, const char *t, size_t len);
1031
1032 /*
1033  * FREE_AND_NULL(ptr) is like free(ptr) followed by ptr = NULL. Note
1034  * that ptr is used twice, so don't pass e.g. ptr++.
1035  */
1036 #define FREE_AND_NULL(p) do { free(p); (p) = NULL; } while (0)
1037
1038 #define ALLOC_ARRAY(x, alloc) (x) = xmalloc(st_mult(sizeof(*(x)), (alloc)))
1039 #define CALLOC_ARRAY(x, alloc) (x) = xcalloc((alloc), sizeof(*(x)))
1040 #define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc)))
1041
1042 #define COPY_ARRAY(dst, src, n) copy_array((dst), (src), (n), sizeof(*(dst)) + \
1043         BUILD_ASSERT_OR_ZERO(sizeof(*(dst)) == sizeof(*(src))))
1044 static inline void copy_array(void *dst, const void *src, size_t n, size_t size)
1045 {
1046         if (n)
1047                 memcpy(dst, src, st_mult(size, n));
1048 }
1049
1050 #define MOVE_ARRAY(dst, src, n) move_array((dst), (src), (n), sizeof(*(dst)) + \
1051         BUILD_ASSERT_OR_ZERO(sizeof(*(dst)) == sizeof(*(src))))
1052 static inline void move_array(void *dst, const void *src, size_t n, size_t size)
1053 {
1054         if (n)
1055                 memmove(dst, src, st_mult(size, n));
1056 }
1057
1058 /*
1059  * These functions help you allocate structs with flex arrays, and copy
1060  * the data directly into the array. For example, if you had:
1061  *
1062  *   struct foo {
1063  *     int bar;
1064  *     char name[FLEX_ARRAY];
1065  *   };
1066  *
1067  * you can do:
1068  *
1069  *   struct foo *f;
1070  *   FLEX_ALLOC_MEM(f, name, src, len);
1071  *
1072  * to allocate a "foo" with the contents of "src" in the "name" field.
1073  * The resulting struct is automatically zero'd, and the flex-array field
1074  * is NUL-terminated (whether the incoming src buffer was or not).
1075  *
1076  * The FLEXPTR_* variants operate on structs that don't use flex-arrays,
1077  * but do want to store a pointer to some extra data in the same allocated
1078  * block. For example, if you have:
1079  *
1080  *   struct foo {
1081  *     char *name;
1082  *     int bar;
1083  *   };
1084  *
1085  * you can do:
1086  *
1087  *   struct foo *f;
1088  *   FLEXPTR_ALLOC_STR(f, name, src);
1089  *
1090  * and "name" will point to a block of memory after the struct, which will be
1091  * freed along with the struct (but the pointer can be repointed anywhere).
1092  *
1093  * The *_STR variants accept a string parameter rather than a ptr/len
1094  * combination.
1095  *
1096  * Note that these macros will evaluate the first parameter multiple
1097  * times, and it must be assignable as an lvalue.
1098  */
1099 #define FLEX_ALLOC_MEM(x, flexname, buf, len) do { \
1100         size_t flex_array_len_ = (len); \
1101         (x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
1102         memcpy((void *)(x)->flexname, (buf), flex_array_len_); \
1103 } while (0)
1104 #define FLEXPTR_ALLOC_MEM(x, ptrname, buf, len) do { \
1105         size_t flex_array_len_ = (len); \
1106         (x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
1107         memcpy((x) + 1, (buf), flex_array_len_); \
1108         (x)->ptrname = (void *)((x)+1); \
1109 } while(0)
1110 #define FLEX_ALLOC_STR(x, flexname, str) \
1111         FLEX_ALLOC_MEM((x), flexname, (str), strlen(str))
1112 #define FLEXPTR_ALLOC_STR(x, ptrname, str) \
1113         FLEXPTR_ALLOC_MEM((x), ptrname, (str), strlen(str))
1114
1115 static inline char *xstrdup_or_null(const char *str)
1116 {
1117         return str ? xstrdup(str) : NULL;
1118 }
1119
1120 static inline size_t xsize_t(off_t len)
1121 {
1122         if (len < 0 || (uintmax_t) len > SIZE_MAX)
1123                 die("Cannot handle files this big");
1124         return (size_t) len;
1125 }
1126
1127 __attribute__((format (printf, 3, 4)))
1128 int xsnprintf(char *dst, size_t max, const char *fmt, ...);
1129
1130 #ifndef HOST_NAME_MAX
1131 #define HOST_NAME_MAX 256
1132 #endif
1133
1134 int xgethostname(char *buf, size_t len);
1135
1136 /* in ctype.c, for kwset users */
1137 extern const unsigned char tolower_trans_tbl[256];
1138
1139 /* Sane ctype - no locale, and works with signed chars */
1140 #undef isascii
1141 #undef isspace
1142 #undef isdigit
1143 #undef isalpha
1144 #undef isalnum
1145 #undef isprint
1146 #undef islower
1147 #undef isupper
1148 #undef tolower
1149 #undef toupper
1150 #undef iscntrl
1151 #undef ispunct
1152 #undef isxdigit
1153
1154 extern const unsigned char sane_ctype[256];
1155 #define GIT_SPACE 0x01
1156 #define GIT_DIGIT 0x02
1157 #define GIT_ALPHA 0x04
1158 #define GIT_GLOB_SPECIAL 0x08
1159 #define GIT_REGEX_SPECIAL 0x10
1160 #define GIT_PATHSPEC_MAGIC 0x20
1161 #define GIT_CNTRL 0x40
1162 #define GIT_PUNCT 0x80
1163 #define sane_istest(x,mask) ((sane_ctype[(unsigned char)(x)] & (mask)) != 0)
1164 #define isascii(x) (((x) & ~0x7f) == 0)
1165 #define isspace(x) sane_istest(x,GIT_SPACE)
1166 #define isdigit(x) sane_istest(x,GIT_DIGIT)
1167 #define isalpha(x) sane_istest(x,GIT_ALPHA)
1168 #define isalnum(x) sane_istest(x,GIT_ALPHA | GIT_DIGIT)
1169 #define isprint(x) ((x) >= 0x20 && (x) <= 0x7e)
1170 #define islower(x) sane_iscase(x, 1)
1171 #define isupper(x) sane_iscase(x, 0)
1172 #define is_glob_special(x) sane_istest(x,GIT_GLOB_SPECIAL)
1173 #define is_regex_special(x) sane_istest(x,GIT_GLOB_SPECIAL | GIT_REGEX_SPECIAL)
1174 #define iscntrl(x) (sane_istest(x,GIT_CNTRL))
1175 #define ispunct(x) sane_istest(x, GIT_PUNCT | GIT_REGEX_SPECIAL | \
1176                 GIT_GLOB_SPECIAL | GIT_PATHSPEC_MAGIC)
1177 #define isxdigit(x) (hexval_table[(unsigned char)(x)] != -1)
1178 #define tolower(x) sane_case((unsigned char)(x), 0x20)
1179 #define toupper(x) sane_case((unsigned char)(x), 0)
1180 #define is_pathspec_magic(x) sane_istest(x,GIT_PATHSPEC_MAGIC)
1181
1182 static inline int sane_case(int x, int high)
1183 {
1184         if (sane_istest(x, GIT_ALPHA))
1185                 x = (x & ~0x20) | high;
1186         return x;
1187 }
1188
1189 static inline int sane_iscase(int x, int is_lower)
1190 {
1191         if (!sane_istest(x, GIT_ALPHA))
1192                 return 0;
1193
1194         if (is_lower)
1195                 return (x & 0x20) != 0;
1196         else
1197                 return (x & 0x20) == 0;
1198 }
1199
1200 /*
1201  * Like skip_prefix, but compare case-insensitively. Note that the comparison
1202  * is done via tolower(), so it is strictly ASCII (no multi-byte characters or
1203  * locale-specific conversions).
1204  */
1205 static inline int skip_iprefix(const char *str, const char *prefix,
1206                                const char **out)
1207 {
1208         do {
1209                 if (!*prefix) {
1210                         *out = str;
1211                         return 1;
1212                 }
1213         } while (tolower(*str++) == tolower(*prefix++));
1214         return 0;
1215 }
1216
1217 static inline int strtoul_ui(char const *s, int base, unsigned int *result)
1218 {
1219         unsigned long ul;
1220         char *p;
1221
1222         errno = 0;
1223         /* negative values would be accepted by strtoul */
1224         if (strchr(s, '-'))
1225                 return -1;
1226         ul = strtoul(s, &p, base);
1227         if (errno || *p || p == s || (unsigned int) ul != ul)
1228                 return -1;
1229         *result = ul;
1230         return 0;
1231 }
1232
1233 static inline int strtol_i(char const *s, int base, int *result)
1234 {
1235         long ul;
1236         char *p;
1237
1238         errno = 0;
1239         ul = strtol(s, &p, base);
1240         if (errno || *p || p == s || (int) ul != ul)
1241                 return -1;
1242         *result = ul;
1243         return 0;
1244 }
1245
1246 void git_stable_qsort(void *base, size_t nmemb, size_t size,
1247                       int(*compar)(const void *, const void *));
1248 #ifdef INTERNAL_QSORT
1249 #define qsort git_stable_qsort
1250 #endif
1251
1252 #define QSORT(base, n, compar) sane_qsort((base), (n), sizeof(*(base)), compar)
1253 static inline void sane_qsort(void *base, size_t nmemb, size_t size,
1254                               int(*compar)(const void *, const void *))
1255 {
1256         if (nmemb > 1)
1257                 qsort(base, nmemb, size, compar);
1258 }
1259
1260 #define STABLE_QSORT(base, n, compar) \
1261         git_stable_qsort((base), (n), sizeof(*(base)), compar)
1262
1263 #ifndef HAVE_ISO_QSORT_S
1264 int git_qsort_s(void *base, size_t nmemb, size_t size,
1265                 int (*compar)(const void *, const void *, void *), void *ctx);
1266 #define qsort_s git_qsort_s
1267 #endif
1268
1269 #define QSORT_S(base, n, compar, ctx) do {                      \
1270         if (qsort_s((base), (n), sizeof(*(base)), compar, ctx)) \
1271                 BUG("qsort_s() failed");                        \
1272 } while (0)
1273
1274 #ifndef REG_STARTEND
1275 #error "Git requires REG_STARTEND support. Compile with NO_REGEX=NeedsStartEnd"
1276 #endif
1277
1278 static inline int regexec_buf(const regex_t *preg, const char *buf, size_t size,
1279                               size_t nmatch, regmatch_t pmatch[], int eflags)
1280 {
1281         assert(nmatch > 0 && pmatch);
1282         pmatch[0].rm_so = 0;
1283         pmatch[0].rm_eo = size;
1284         return regexec(preg, buf, nmatch, pmatch, eflags | REG_STARTEND);
1285 }
1286
1287 #ifndef DIR_HAS_BSD_GROUP_SEMANTICS
1288 # define FORCE_DIR_SET_GID S_ISGID
1289 #else
1290 # define FORCE_DIR_SET_GID 0
1291 #endif
1292
1293 #ifdef NO_NSEC
1294 #undef USE_NSEC
1295 #define ST_CTIME_NSEC(st) 0
1296 #define ST_MTIME_NSEC(st) 0
1297 #else
1298 #ifdef USE_ST_TIMESPEC
1299 #define ST_CTIME_NSEC(st) ((unsigned int)((st).st_ctimespec.tv_nsec))
1300 #define ST_MTIME_NSEC(st) ((unsigned int)((st).st_mtimespec.tv_nsec))
1301 #else
1302 #define ST_CTIME_NSEC(st) ((unsigned int)((st).st_ctim.tv_nsec))
1303 #define ST_MTIME_NSEC(st) ((unsigned int)((st).st_mtim.tv_nsec))
1304 #endif
1305 #endif
1306
1307 #ifdef UNRELIABLE_FSTAT
1308 #define fstat_is_reliable() 0
1309 #else
1310 #define fstat_is_reliable() 1
1311 #endif
1312
1313 #ifndef va_copy
1314 /*
1315  * Since an obvious implementation of va_list would be to make it a
1316  * pointer into the stack frame, a simple assignment will work on
1317  * many systems.  But let's try to be more portable.
1318  */
1319 #ifdef __va_copy
1320 #define va_copy(dst, src) __va_copy(dst, src)
1321 #else
1322 #define va_copy(dst, src) ((dst) = (src))
1323 #endif
1324 #endif
1325
1326 /* usage.c: only to be used for testing BUG() implementation (see test-tool) */
1327 extern int BUG_exit_code;
1328
1329 __attribute__((format (printf, 3, 4))) NORETURN
1330 void BUG_fl(const char *file, int line, const char *fmt, ...);
1331 #define BUG(...) BUG_fl(__FILE__, __LINE__, __VA_ARGS__)
1332
1333 #ifndef FSYNC_METHOD_DEFAULT
1334 #ifdef __APPLE__
1335 #define FSYNC_METHOD_DEFAULT FSYNC_METHOD_WRITEOUT_ONLY
1336 #else
1337 #define FSYNC_METHOD_DEFAULT FSYNC_METHOD_FSYNC
1338 #endif
1339 #endif
1340
1341 enum fsync_action {
1342         FSYNC_WRITEOUT_ONLY,
1343         FSYNC_HARDWARE_FLUSH
1344 };
1345
1346 /*
1347  * Issues an fsync against the specified file according to the specified mode.
1348  *
1349  * FSYNC_WRITEOUT_ONLY attempts to use interfaces available on some operating
1350  * systems to flush the OS cache without issuing a flush command to the storage
1351  * controller. If those interfaces are unavailable, the function fails with
1352  * ENOSYS.
1353  *
1354  * FSYNC_HARDWARE_FLUSH does an OS writeout and hardware flush to ensure that
1355  * changes are durable. It is not expected to fail.
1356  */
1357 int git_fsync(int fd, enum fsync_action action);
1358
1359 /*
1360  * Writes out trace statistics for fsync using the trace2 API.
1361  */
1362 void trace_git_fsync_stats(void);
1363
1364 /*
1365  * Preserves errno, prints a message, but gives no warning for ENOENT.
1366  * Returns 0 on success, which includes trying to unlink an object that does
1367  * not exist.
1368  */
1369 int unlink_or_warn(const char *path);
1370  /*
1371   * Tries to unlink file.  Returns 0 if unlink succeeded
1372   * or the file already didn't exist.  Returns -1 and
1373   * appends a message to err suitable for
1374   * 'error("%s", err->buf)' on error.
1375   */
1376 int unlink_or_msg(const char *file, struct strbuf *err);
1377 /*
1378  * Preserves errno, prints a message, but gives no warning for ENOENT.
1379  * Returns 0 on success, which includes trying to remove a directory that does
1380  * not exist.
1381  */
1382 int rmdir_or_warn(const char *path);
1383 /*
1384  * Calls the correct function out of {unlink,rmdir}_or_warn based on
1385  * the supplied file mode.
1386  */
1387 int remove_or_warn(unsigned int mode, const char *path);
1388
1389 /*
1390  * Call access(2), but warn for any error except "missing file"
1391  * (ENOENT or ENOTDIR).
1392  */
1393 #define ACCESS_EACCES_OK (1U << 0)
1394 int access_or_warn(const char *path, int mode, unsigned flag);
1395 int access_or_die(const char *path, int mode, unsigned flag);
1396
1397 /* Warn on an inaccessible file if errno indicates this is an error */
1398 int warn_on_fopen_errors(const char *path);
1399
1400 /*
1401  * Open with O_NOFOLLOW, or equivalent. Note that the fallback equivalent
1402  * may be racy. Do not use this as protection against an attacker who can
1403  * simultaneously create paths.
1404  */
1405 int open_nofollow(const char *path, int flags);
1406
1407 #ifndef SHELL_PATH
1408 # define SHELL_PATH "/bin/sh"
1409 #endif
1410
1411 #ifndef _POSIX_THREAD_SAFE_FUNCTIONS
1412 static inline void flockfile(FILE *fh)
1413 {
1414         ; /* nothing */
1415 }
1416 static inline void funlockfile(FILE *fh)
1417 {
1418         ; /* nothing */
1419 }
1420 #define getc_unlocked(fh) getc(fh)
1421 #endif
1422
1423 #ifdef FILENO_IS_A_MACRO
1424 int git_fileno(FILE *stream);
1425 # ifndef COMPAT_CODE_FILENO
1426 #  undef fileno
1427 #  define fileno(p) git_fileno(p)
1428 # endif
1429 #endif
1430
1431 #ifdef NEED_ACCESS_ROOT_HANDLER
1432 int git_access(const char *path, int mode);
1433 # ifndef COMPAT_CODE_ACCESS
1434 #  ifdef access
1435 #  undef access
1436 #  endif
1437 #  define access(path, mode) git_access(path, mode)
1438 # endif
1439 #endif
1440
1441 /*
1442  * Our code often opens a path to an optional file, to work on its
1443  * contents when we can successfully open it.  We can ignore a failure
1444  * to open if such an optional file does not exist, but we do want to
1445  * report a failure in opening for other reasons (e.g. we got an I/O
1446  * error, or the file is there, but we lack the permission to open).
1447  *
1448  * Call this function after seeing an error from open() or fopen() to
1449  * see if the errno indicates a missing file that we can safely ignore.
1450  */
1451 static inline int is_missing_file_error(int errno_)
1452 {
1453         return (errno_ == ENOENT || errno_ == ENOTDIR);
1454 }
1455
1456 int cmd_main(int, const char **);
1457
1458 /*
1459  * Intercept all calls to exit() and route them to trace2 to
1460  * optionally emit a message before calling the real exit().
1461  */
1462 int trace2_cmd_exit_fl(const char *file, int line, int code);
1463 #define exit(code) exit(trace2_cmd_exit_fl(__FILE__, __LINE__, (code)))
1464
1465 /*
1466  * You can mark a stack variable with UNLEAK(var) to avoid it being
1467  * reported as a leak by tools like LSAN or valgrind. The argument
1468  * should generally be the variable itself (not its address and not what
1469  * it points to). It's safe to use this on pointers which may already
1470  * have been freed, or on pointers which may still be in use.
1471  *
1472  * Use this _only_ for a variable that leaks by going out of scope at
1473  * program exit (so only from cmd_* functions or their direct helpers).
1474  * Normal functions, especially those which may be called multiple
1475  * times, should actually free their memory. This is only meant as
1476  * an annotation, and does nothing in non-leak-checking builds.
1477  */
1478 #ifdef SUPPRESS_ANNOTATED_LEAKS
1479 void unleak_memory(const void *ptr, size_t len);
1480 #define UNLEAK(var) unleak_memory(&(var), sizeof(var))
1481 #else
1482 #define UNLEAK(var) do {} while (0)
1483 #endif
1484
1485 #define z_const
1486 #include <zlib.h>
1487
1488 #if ZLIB_VERNUM < 0x1290
1489 /*
1490  * This is uncompress2, which is only available in zlib >= 1.2.9
1491  * (released as of early 2017). See compat/zlib-uncompress2.c.
1492  */
1493 int uncompress2(Bytef *dest, uLongf *destLen, const Bytef *source,
1494                 uLong *sourceLen);
1495 #endif
1496
1497 /*
1498  * This include must come after system headers, since it introduces macros that
1499  * replace system names.
1500  */
1501 #include "banned.h"
1502
1503 /*
1504  * container_of - Get the address of an object containing a field.
1505  *
1506  * @ptr: pointer to the field.
1507  * @type: type of the object.
1508  * @member: name of the field within the object.
1509  */
1510 #define container_of(ptr, type, member) \
1511         ((type *) ((char *)(ptr) - offsetof(type, member)))
1512
1513 /*
1514  * helper function for `container_of_or_null' to avoid multiple
1515  * evaluation of @ptr
1516  */
1517 static inline void *container_of_or_null_offset(void *ptr, size_t offset)
1518 {
1519         return ptr ? (char *)ptr - offset : NULL;
1520 }
1521
1522 /*
1523  * like `container_of', but allows returned value to be NULL
1524  */
1525 #define container_of_or_null(ptr, type, member) \
1526         (type *)container_of_or_null_offset(ptr, offsetof(type, member))
1527
1528 /*
1529  * like offsetof(), but takes a pointer to a variable of type which
1530  * contains @member, instead of a specified type.
1531  * @ptr is subject to multiple evaluation since we can't rely on __typeof__
1532  * everywhere.
1533  */
1534 #if defined(__GNUC__) /* clang sets this, too */
1535 #define OFFSETOF_VAR(ptr, member) offsetof(__typeof__(*ptr), member)
1536 #else /* !__GNUC__ */
1537 #define OFFSETOF_VAR(ptr, member) \
1538         ((uintptr_t)&(ptr)->member - (uintptr_t)(ptr))
1539 #endif /* !__GNUC__ */
1540
1541 void sleep_millisec(int millisec);
1542
1543 /*
1544  * Generate len bytes from the system cryptographically secure PRNG.
1545  * Returns 0 on success and -1 on error, setting errno.  The inability to
1546  * satisfy the full request is an error.
1547  */
1548 int csprng_bytes(void *buf, size_t len);
1549
1550 #endif