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 struct strbuf;
  27
  28
  29 #define _FILE_OFFSET_BITS 64
  30
  31
  32 /* Derived from Linux "Features Test Macro" header
  33  * Convenience macros to test the versions of gcc (or
  34  * a compatible compiler).
  35  * Use them like this:
  36  *  #if GIT_GNUC_PREREQ (2,8)
  37  *   ... code requiring gcc 2.8 or later ...
  38  *  #endif
  39 */
  40 #if defined(__GNUC__) && defined(__GNUC_MINOR__)
  41 # define GIT_GNUC_PREREQ(maj, min) \
  42         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
  43 #else
  44  #define GIT_GNUC_PREREQ(maj, min) 0
  45 #endif
  46
  47
  48 #ifndef FLEX_ARRAY
  49 /*
  50  * See if our compiler is known to support flexible array members.
  51  */
  52
  53 /*
  54  * Check vendor specific quirks first, before checking the
  55  * __STDC_VERSION__, as vendor compilers can lie and we need to be
  56  * able to work them around.  Note that by not defining FLEX_ARRAY
  57  * here, we can fall back to use the "safer but a bit wasteful" one
  58  * later.
  59  */
  60 #if defined(__SUNPRO_C) && (__SUNPRO_C <= 0x580)
  61 #elif defined(__GNUC__)
  62 # if (__GNUC__ >= 3)
  63 #  define FLEX_ARRAY /* empty */
  64 # else
  65 #  define FLEX_ARRAY 0 /* older GNU extension */
  66 # endif
  67 #elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
  68 # define FLEX_ARRAY /* empty */
  69 #endif
  70
  71 /*
  72  * Otherwise, default to safer but a bit wasteful traditional style
  73  */
  74 #ifndef FLEX_ARRAY
  75 # define FLEX_ARRAY 1
  76 #endif
  77 #endif
  78
  79
  80 /*
  81  * BUILD_ASSERT_OR_ZERO - assert a build-time dependency, as an expression.
  82  * @cond: the compile-time condition which must be true.
  83  *
  84  * Your compile will fail if the condition isn't true, or can't be evaluated
  85  * by the compiler.  This can be used in an expression: its value is "0".
  86  *
  87  * Example:
  88  *      #define foo_to_char(foo)                                        \
  89  *               ((char *)(foo)                                         \
  90  *                + BUILD_ASSERT_OR_ZERO(offsetof(struct foo, string) == 0))
  91  */
  92 #define BUILD_ASSERT_OR_ZERO(cond) \
  93         (sizeof(char [1 - 2*!(cond)]) - 1)
  94
  95 #if GIT_GNUC_PREREQ(3, 1)
  96  /* &arr[0] degrades to a pointer: a different type from an array */
  97 # define BARF_UNLESS_AN_ARRAY(arr)                                              \
  98         BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(__typeof__(arr), \
  99                                                            __typeof__(&(arr)[0])))
 100 #else
 101 # define BARF_UNLESS_AN_ARRAY(arr) 0
 102 #endif
 103 /*
 104  * ARRAY_SIZE - get the number of elements in a visible array
 105  * @x: the array whose size you want.
 106  *
 107  * This does not work on pointers, or arrays declared as [], or
 108  * function parameters.  With correct compiler support, such usage
 109  * will cause a build error (see the build_assert_or_zero macro).
 110  */
 111 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + BARF_UNLESS_AN_ARRAY(x))
 112
 113 #define bitsizeof(x)  (CHAR_BIT * sizeof(x))
 114
 115 #define maximum_signed_value_of_type(a) \
 116     (INTMAX_MAX >> (bitsizeof(intmax_t) - bitsizeof(a)))
 117
 118 #define maximum_unsigned_value_of_type(a) \
 119     (UINTMAX_MAX >> (bitsizeof(uintmax_t) - bitsizeof(a)))
 120
 121 /*
 122  * Signed integer overflow is undefined in C, so here's a helper macro
 123  * to detect if the sum of two integers will overflow.
 124  *
 125  * Requires: a >= 0, typeof(a) equals typeof(b)
 126  */
 127 #define signed_add_overflows(a, b) \
 128     ((b) > maximum_signed_value_of_type(a) - (a))
 129
 130 #define unsigned_add_overflows(a, b) \
 131     ((b) > maximum_unsigned_value_of_type(a) - (a))
 132
 133 /*
 134  * Returns true if the multiplication of "a" and "b" will
 135  * overflow. The types of "a" and "b" must match and must be unsigned.
 136  * Note that this macro evaluates "a" twice!
 137  */
 138 #define unsigned_mult_overflows(a, b) \
 139     ((a) && (b) > maximum_unsigned_value_of_type(a) / (a))
 140
 141 /*
 142  * Returns true if the left shift of "a" by "shift" bits will
 143  * overflow. The type of "a" must be unsigned.
 144  */
 145 #define unsigned_left_shift_overflows(a, shift) \
 146     ((shift) < bitsizeof(a) && \
 147      (a) > maximum_unsigned_value_of_type(a) >> (shift))
 148
 149 #ifdef __GNUC__
 150 #define TYPEOF(x) (__typeof__(x))
 151 #else
 152 #define TYPEOF(x)
 153 #endif
 154
 155 #define MSB(x, bits) ((x) & TYPEOF(x)(~0ULL << (bitsizeof(x) - (bits))))
 156 #define HAS_MULTI_BITS(i)  ((i) & ((i) - 1))  /* checks if an integer has more than 1 bit set */
 157
 158 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
 159
 160 /* Approximation of the length of the decimal representation of this type. */
 161 #define decimal_length(x)       ((int)(sizeof(x) * 2.56 + 0.5) + 1)
 162
 163 #ifdef __MINGW64__
 164 #define _POSIX_C_SOURCE 1
 165 #elif defined(__sun__)
 166  /*
 167   * On Solaris, when _XOPEN_EXTENDED is set, its header file
 168   * forces the programs to be XPG4v2, defeating any _XOPEN_SOURCE
 169   * setting to say we are XPG5 or XPG6.  Also on Solaris,
 170   * XPG6 programs must be compiled with a c99 compiler, while
 171   * non XPG6 programs must be compiled with a pre-c99 compiler.
 172   */
 173 # if __STDC_VERSION__ - 0 >= 199901L
 174 # define _XOPEN_SOURCE 600
 175 # else
 176 # define _XOPEN_SOURCE 500
 177 # endif
 178 #elif !defined(__APPLE__) && !defined(__FreeBSD__) && !defined(__USLC__) && \
 179       !defined(_M_UNIX) && !defined(__sgi) && !defined(__DragonFly__) && \
 180       !defined(__TANDEM) && !defined(__QNX__) && !defined(__MirBSD__) && \
 181       !defined(__CYGWIN__)
 182 #define _XOPEN_SOURCE 600 /* glibc2 and AIX 5.3L need 500, OpenBSD needs 600 for S_ISLNK() */
 183 #define _XOPEN_SOURCE_EXTENDED 1 /* AIX 5.3L needs this */
 184 #endif
 185 #define _ALL_SOURCE 1
 186 #define _GNU_SOURCE 1
 187 #define _BSD_SOURCE 1
 188 #define _DEFAULT_SOURCE 1
 189 #define _NETBSD_SOURCE 1
 190 #define _SGI_SOURCE 1
 191
 192 #if defined(WIN32) && !defined(__CYGWIN__) /* Both MinGW and MSVC */
 193 # if !defined(_WIN32_WINNT)
 194 #  define _WIN32_WINNT 0x0600
 195 # endif
 196 #define WIN32_LEAN_AND_MEAN  /* stops windows.h including winsock.h */
 197 #include <winsock2.h>
 198 #ifndef NO_UNIX_SOCKETS
 199 #include <afunix.h>
 200 #endif
 201 #include <windows.h>
 202 #define GIT_WINDOWS_NATIVE
 203 #endif
 204
 205 #include <unistd.h>
 206 #include <stdio.h>
 207 #include <sys/stat.h>
 208 #include <fcntl.h>
 209 #include <stddef.h>
 210 #include <stdlib.h>
 211 #include <stdarg.h>
 212 #include <string.h>
 213 #ifdef HAVE_STRINGS_H
 214 #include <strings.h> /* for strcasecmp() */
 215 #endif
 216 #include <errno.h>
 217 #include <limits.h>
 218 #ifdef NEEDS_SYS_PARAM_H
 219 #include <sys/param.h>
 220 #endif
 221 #include <sys/types.h>
 222 #include <dirent.h>
 223 #include <sys/time.h>
 224 #include <time.h>
 225 #include <signal.h>
 226 #include <assert.h>
 227 #include <regex.h>
 228 #include <utime.h>
 229 #include <syslog.h>
 230 #if !defined(NO_POLL_H)
 231 #include <poll.h>
 232 #elif !defined(NO_SYS_POLL_H)
 233 #include <sys/poll.h>
 234 #else
 235 /* Pull the compat stuff */
 236 #include <poll.h>
 237 #endif
 238 #ifdef HAVE_BSD_SYSCTL
 239 #include <sys/sysctl.h>
 240 #endif
 241
 242 /* Used by compat/win32/path-utils.h, and more */
 243 static inline int is_xplatform_dir_sep(int c)
 244 {
 245         return c == '/' || c == '\\';
 246 }
 247
 248 #if defined(__CYGWIN__)
 249 #include "compat/win32/path-utils.h"
 250 #endif
 251 #if defined(__MINGW32__)
 252 /* pull in Windows compatibility stuff */
 253 #include "compat/win32/path-utils.h"
 254 #include "compat/mingw.h"
 255 #elif defined(_MSC_VER)
 256 #include "compat/win32/path-utils.h"
 257 #include "compat/msvc.h"
 258 #else
 259 #include <sys/utsname.h>
 260 #include <sys/wait.h>
 261 #include <sys/resource.h>
 262 #include <sys/socket.h>
 263 #include <sys/ioctl.h>
 264 #include <termios.h>
 265 #ifndef NO_SYS_SELECT_H
 266 #include <sys/select.h>
 267 #endif
 268 #include <netinet/in.h>
 269 #include <netinet/tcp.h>
 270 #include <arpa/inet.h>
 271 #include <netdb.h>
 272 #include <pwd.h>
 273 #include <sys/un.h>
 274 #ifndef NO_INTTYPES_H
 275 #include <inttypes.h>
 276 #else
 277 #include <stdint.h>
 278 #endif
 279 #ifdef HAVE_ARC4RANDOM_LIBBSD
 280 #include <bsd/stdlib.h>
 281 #endif
 282 #ifdef HAVE_GETRANDOM
 283 #include <sys/random.h>
 284 #endif
 285 #ifdef NO_INTPTR_T
 286 /*
 287  * On I16LP32, ILP32 and LP64 "long" is the safe bet, however
 288  * on LLP86, IL33LLP64 and P64 it needs to be "long long",
 289  * while on IP16 and IP16L32 it is "int" (resp. "short")
 290  * Size needs to match (or exceed) 'sizeof(void *)'.
 291  * We can't take "long long" here as not everybody has it.
 292  */
 293 typedef long intptr_t;
 294 typedef unsigned long uintptr_t;
 295 #endif
 296 #undef _ALL_SOURCE /* AIX 5.3L defines a struct list with _ALL_SOURCE. */
 297 #include <grp.h>
 298 #define _ALL_SOURCE 1
 299 #endif
 300
 301 /* used on Mac OS X */
 302 #ifdef PRECOMPOSE_UNICODE
 303 #include "compat/precompose_utf8.h"
 304 #else
 305 static inline const char *precompose_argv_prefix(int argc, const char **argv, const char *prefix)
 306 {
 307         return prefix;
 308 }
 309 static inline const char *precompose_string_if_needed(const char *in)
 310 {
 311         return in;
 312 }
 313
 314 #define probe_utf8_pathname_composition()
 315 #endif
 316
 317 #ifdef MKDIR_WO_TRAILING_SLASH
 318 #define mkdir(a,b) compat_mkdir_wo_trailing_slash((a),(b))
 319 int compat_mkdir_wo_trailing_slash(const char*, mode_t);
 320 #endif
 321
 322 #ifdef NO_STRUCT_ITIMERVAL
 323 struct itimerval {
 324         struct timeval it_interval;
 325         struct timeval it_value;
 326 };
 327 #endif
 328
 329 #ifdef NO_SETITIMER
 330 static inline int setitimer(int which, const struct itimerval *value, struct itimerval *newvalue) {
 331         return 0; /* pretend success */
 332 }
 333 #endif
 334
 335 #ifndef NO_LIBGEN_H
 336 #include <libgen.h>
 337 #else
 338 #define basename gitbasename
 339 char *gitbasename(char *);
 340 #define dirname gitdirname
 341 char *gitdirname(char *);
 342 #endif
 343
 344 #ifndef NO_ICONV
 345 #include <iconv.h>
 346 #endif
 347
 348 #ifndef NO_OPENSSL
 349 #ifdef __APPLE__
 350 #define __AVAILABILITY_MACROS_USES_AVAILABILITY 0
 351 #include <AvailabilityMacros.h>
 352 #undef DEPRECATED_ATTRIBUTE
 353 #define DEPRECATED_ATTRIBUTE
 354 #undef __AVAILABILITY_MACROS_USES_AVAILABILITY
 355 #endif
 356 #include <openssl/ssl.h>
 357 #include <openssl/err.h>
 358 #endif
 359
 360 #ifdef HAVE_SYSINFO
 361 # include <sys/sysinfo.h>
 362 #endif
 363
 364 /* On most systems <netdb.h> would have given us this, but
 365  * not on some systems (e.g. z/OS).
 366  */
 367 #ifndef NI_MAXHOST
 368 #define NI_MAXHOST 1025
 369 #endif
 370
 371 #ifndef NI_MAXSERV
 372 #define NI_MAXSERV 32
 373 #endif
 374
 375 /* On most systems <limits.h> would have given us this, but
 376  * not on some systems (e.g. GNU/Hurd).
 377  */
 378 #ifndef PATH_MAX
 379 #define PATH_MAX 4096
 380 #endif
 381
 382 typedef uintmax_t timestamp_t;
 383 #define PRItime PRIuMAX
 384 #define parse_timestamp strtoumax
 385 #define TIME_MAX UINTMAX_MAX
 386 #define TIME_MIN 0
 387
 388 #ifndef PATH_SEP
 389 #define PATH_SEP ':'
 390 #endif
 391
 392 #ifdef HAVE_PATHS_H
 393 #include <paths.h>
 394 #endif
 395 #ifndef _PATH_DEFPATH
 396 #define _PATH_DEFPATH "/usr/local/bin:/usr/bin:/bin"
 397 #endif
 398
 399 #ifndef platform_core_config
 400 static inline int noop_core_config(const char *var, const char *value, void *cb)
 401 {
 402         return 0;
 403 }
 404 #define platform_core_config noop_core_config
 405 #endif
 406
 407 int lstat_cache_aware_rmdir(const char *path);
 408 #if !defined(__MINGW32__) && !defined(_MSC_VER)
 409 #define rmdir lstat_cache_aware_rmdir
 410 #endif
 411
 412 #ifndef has_dos_drive_prefix
 413 static inline int git_has_dos_drive_prefix(const char *path)
 414 {
 415         return 0;
 416 }
 417 #define has_dos_drive_prefix git_has_dos_drive_prefix
 418 #endif
 419
 420 #ifndef skip_dos_drive_prefix
 421 static inline int git_skip_dos_drive_prefix(char **path)
 422 {
 423         return 0;
 424 }
 425 #define skip_dos_drive_prefix git_skip_dos_drive_prefix
 426 #endif
 427
 428 static inline int git_is_dir_sep(int c)
 429 {
 430         return c == '/';
 431 }
 432 #ifndef is_dir_sep
 433 #define is_dir_sep git_is_dir_sep
 434 #endif
 435
 436 #ifndef offset_1st_component
 437 static inline int git_offset_1st_component(const char *path)
 438 {
 439         return is_dir_sep(path[0]);
 440 }
 441 #define offset_1st_component git_offset_1st_component
 442 #endif
 443
 444 #ifndef is_valid_path
 445 #define is_valid_path(path) 1
 446 #endif
 447
 448 #ifndef is_path_owned_by_current_user
 449
 450 #ifdef __TANDEM
 451 #define ROOT_UID 65535
 452 #else
 453 #define ROOT_UID 0
 454 #endif
 455
 456 /*
 457  * Do not use this function when
 458  * (1) geteuid() did not say we are running as 'root', or
 459  * (2) using this function will compromise the system.
 460  *
 461  * PORTABILITY WARNING:
 462  * This code assumes uid_t is unsigned because that is what sudo does.
 463  * If your uid_t type is signed and all your ids are positive then it
 464  * should all work fine.
 465  * If your version of sudo uses negative values for uid_t or it is
 466  * buggy and return an overflowed value in SUDO_UID, then git might
 467  * fail to grant access to your repository properly or even mistakenly
 468  * grant access to someone else.
 469  * In the unlikely scenario this happened to you, and that is how you
 470  * got to this message, we would like to know about it; so sent us an
 471  * email to git@vger.kernel.org indicating which platform you are
 472  * using and which version of sudo, so we can improve this logic and
 473  * maybe provide you with a patch that would prevent this issue again
 474  * in the future.
 475  */
 476 static inline void extract_id_from_env(const char *env, uid_t *id)
 477 {
 478         const char *real_uid = getenv(env);
 479
 480         /* discard anything empty to avoid a more complex check below */
 481         if (real_uid && *real_uid) {
 482                 char *endptr = NULL;
 483                 unsigned long env_id;
 484
 485                 errno = 0;
 486                 /* silent overflow errors could trigger a bug here */
 487                 env_id = strtoul(real_uid, &endptr, 10);
 488                 if (!*endptr && !errno)
 489                         *id = env_id;
 490         }
 491 }
 492
 493 static inline int is_path_owned_by_current_uid(const char *path, struct strbuf *report)
 494 {
 495         struct stat st;
 496         uid_t euid;
 497
 498         if (lstat(path, &st))
 499                 return 0;
 500
 501         euid = geteuid();
 502         if (euid == ROOT_UID)
 503         {
 504                 if (st.st_uid == ROOT_UID)
 505                         return 1;
 506                 else
 507                         extract_id_from_env("SUDO_UID", &euid);
 508         }
 509
 510         return st.st_uid == euid;
 511 }
 512
 513 #define is_path_owned_by_current_user is_path_owned_by_current_uid
 514 #endif
 515
 516 #ifndef find_last_dir_sep
 517 static inline char *git_find_last_dir_sep(const char *path)
 518 {
 519         return strrchr(path, '/');
 520 }
 521 #define find_last_dir_sep git_find_last_dir_sep
 522 #endif
 523
 524 #ifndef has_dir_sep
 525 static inline int git_has_dir_sep(const char *path)
 526 {
 527         return !!strchr(path, '/');
 528 }
 529 #define has_dir_sep(path) git_has_dir_sep(path)
 530 #endif
 531
 532 #ifndef query_user_email
 533 #define query_user_email() NULL
 534 #endif
 535
 536 #ifdef __TANDEM
 537 #include <floss.h(floss_execl,floss_execlp,floss_execv,floss_execvp)>
 538 #include <floss.h(floss_getpwuid)>
 539 #ifndef NSIG
 540 /*
 541  * NonStop NSE and NSX do not provide NSIG. SIGGUARDIAN(99) is the highest
 542  * known, by detective work using kill -l as a list is all signals
 543  * instead of signal.h where it should be.
 544  */
 545 # define NSIG 100
 546 #endif
 547 #endif
 548
 549 #if defined(__HP_cc) && (__HP_cc >= 61000)
 550 #define NORETURN __attribute__((noreturn))
 551 #define NORETURN_PTR
 552 #elif defined(__GNUC__) && !defined(NO_NORETURN)
 553 #define NORETURN __attribute__((__noreturn__))
 554 #define NORETURN_PTR __attribute__((__noreturn__))
 555 #elif defined(_MSC_VER)
 556 #define NORETURN __declspec(noreturn)
 557 #define NORETURN_PTR
 558 #else
 559 #define NORETURN
 560 #define NORETURN_PTR
 561 #ifndef __GNUC__
 562 #ifndef __attribute__
 563 #define __attribute__(x)
 564 #endif
 565 #endif
 566 #endif
 567
 568 /* The sentinel attribute is valid from gcc version 4.0 */
 569 #if defined(__GNUC__) && (__GNUC__ >= 4)
 570 #define LAST_ARG_MUST_BE_NULL __attribute__((sentinel))
 571 #else
 572 #define LAST_ARG_MUST_BE_NULL
 573 #endif
 574
 575 #define MAYBE_UNUSED __attribute__((__unused__))
 576
 577 #include "compat/bswap.h"
 578
 579 #include "wildmatch.h"
 580
 581 struct strbuf;
 582
 583 /* General helper functions */
 584 NORETURN void usage(const char *err);
 585 NORETURN void usagef(const char *err, ...) __attribute__((format (printf, 1, 2)));
 586 NORETURN void die(const char *err, ...) __attribute__((format (printf, 1, 2)));
 587 NORETURN void die_errno(const char *err, ...) __attribute__((format (printf, 1, 2)));
 588 int die_message(const char *err, ...) __attribute__((format (printf, 1, 2)));
 589 int die_message_errno(const char *err, ...) __attribute__((format (printf, 1, 2)));
 590 int error(const char *err, ...) __attribute__((format (printf, 1, 2)));
 591 int error_errno(const char *err, ...) __attribute__((format (printf, 1, 2)));
 592 void warning(const char *err, ...) __attribute__((format (printf, 1, 2)));
 593 void warning_errno(const char *err, ...) __attribute__((format (printf, 1, 2)));
 594
 595 #ifndef NO_OPENSSL
 596 #ifdef APPLE_COMMON_CRYPTO
 597 #include "compat/apple-common-crypto.h"
 598 #else
 599 #include <openssl/evp.h>
 600 #include <openssl/hmac.h>
 601 #endif /* APPLE_COMMON_CRYPTO */
 602 #include <openssl/x509v3.h>
 603 #endif /* NO_OPENSSL */
 604
 605 #ifdef HAVE_OPENSSL_CSPRNG
 606 #include <openssl/rand.h>
 607 #endif
 608
 609 /*
 610  * Let callers be aware of the constant return value; this can help
 611  * gcc with -Wuninitialized analysis. We restrict this trick to gcc, though,
 612  * because other compilers may be confused by this.
 613  */
 614 #if defined(__GNUC__)
 615 static inline int const_error(void)
 616 {
 617         return -1;
 618 }
 619 #define error(...) (error(__VA_ARGS__), const_error())
 620 #define error_errno(...) (error_errno(__VA_ARGS__), const_error())
 621 #endif
 622
 623 typedef void (*report_fn)(const char *, va_list params);
 624
 625 void set_die_routine(NORETURN_PTR report_fn routine);
 626 report_fn get_die_message_routine(void);
 627 void set_error_routine(report_fn routine);
 628 report_fn get_error_routine(void);
 629 void set_warn_routine(report_fn routine);
 630 report_fn get_warn_routine(void);
 631 void set_die_is_recursing_routine(int (*routine)(void));
 632
 633 int starts_with(const char *str, const char *prefix);
 634 int istarts_with(const char *str, const char *prefix);
 635
 636 /*
 637  * If the string "str" begins with the string found in "prefix", return 1.
 638  * The "out" parameter is set to "str + strlen(prefix)" (i.e., to the point in
 639  * the string right after the prefix).
 640  *
 641  * Otherwise, return 0 and leave "out" untouched.
 642  *
 643  * Examples:
 644  *
 645  *   [extract branch name, fail if not a branch]
 646  *   if (!skip_prefix(ref, "refs/heads/", &branch)
 647  *      return -1;
 648  *
 649  *   [skip prefix if present, otherwise use whole string]
 650  *   skip_prefix(name, "refs/heads/", &name);
 651  */
 652 static inline int skip_prefix(const char *str, const char *prefix,
 653                               const char **out)
 654 {
 655         do {
 656                 if (!*prefix) {
 657                         *out = str;
 658                         return 1;
 659                 }
 660         } while (*str++ == *prefix++);
 661         return 0;
 662 }
 663
 664 /*
 665  * If the string "str" is the same as the string in "prefix", then the "arg"
 666  * parameter is set to the "def" parameter and 1 is returned.
 667  * If the string "str" begins with the string found in "prefix" and then a
 668  * "=" sign, then the "arg" parameter is set to "str + strlen(prefix) + 1"
 669  * (i.e., to the point in the string right after the prefix and the "=" sign),
 670  * and 1 is returned.
 671  *
 672  * Otherwise, return 0 and leave "arg" untouched.
 673  *
 674  * When we accept both a "--key" and a "--key=<val>" option, this function
 675  * can be used instead of !strcmp(arg, "--key") and then
 676  * skip_prefix(arg, "--key=", &arg) to parse such an option.
 677  */
 678 int skip_to_optional_arg_default(const char *str, const char *prefix,
 679                                  const char **arg, const char *def);
 680
 681 static inline int skip_to_optional_arg(const char *str, const char *prefix,
 682                                        const char **arg)
 683 {
 684         return skip_to_optional_arg_default(str, prefix, arg, "");
 685 }
 686
 687 /*
 688  * Like skip_prefix, but promises never to read past "len" bytes of the input
 689  * buffer, and returns the remaining number of bytes in "out" via "outlen".
 690  */
 691 static inline int skip_prefix_mem(const char *buf, size_t len,
 692                                   const char *prefix,
 693                                   const char **out, size_t *outlen)
 694 {
 695         size_t prefix_len = strlen(prefix);
 696         if (prefix_len <= len && !memcmp(buf, prefix, prefix_len)) {
 697                 *out = buf + prefix_len;
 698                 *outlen = len - prefix_len;
 699                 return 1;
 700         }
 701         return 0;
 702 }
 703
 704 /*
 705  * If buf ends with suffix, return 1 and subtract the length of the suffix
 706  * from *len. Otherwise, return 0 and leave *len untouched.
 707  */
 708 static inline int strip_suffix_mem(const char *buf, size_t *len,
 709                                    const char *suffix)
 710 {
 711         size_t suflen = strlen(suffix);
 712         if (*len < suflen || memcmp(buf + (*len - suflen), suffix, suflen))
 713                 return 0;
 714         *len -= suflen;
 715         return 1;
 716 }
 717
 718 /*
 719  * If str ends with suffix, return 1 and set *len to the size of the string
 720  * without the suffix. Otherwise, return 0 and set *len to the size of the
 721  * string.
 722  *
 723  * Note that we do _not_ NUL-terminate str to the new length.
 724  */
 725 static inline int strip_suffix(const char *str, const char *suffix, size_t *len)
 726 {
 727         *len = strlen(str);
 728         return strip_suffix_mem(str, len, suffix);
 729 }
 730
 731 static inline int ends_with(const char *str, const char *suffix)
 732 {
 733         size_t len;
 734         return strip_suffix(str, suffix, &len);
 735 }
 736
 737 #define SWAP(a, b) do {                                         \
 738         void *_swap_a_ptr = &(a);                               \
 739         void *_swap_b_ptr = &(b);                               \
 740         unsigned char _swap_buffer[sizeof(a)];                  \
 741         memcpy(_swap_buffer, _swap_a_ptr, sizeof(a));           \
 742         memcpy(_swap_a_ptr, _swap_b_ptr, sizeof(a) +            \
 743                BUILD_ASSERT_OR_ZERO(sizeof(a) == sizeof(b)));   \
 744         memcpy(_swap_b_ptr, _swap_buffer, sizeof(a));           \
 745 } while (0)
 746
 747 #if defined(NO_MMAP) || defined(USE_WIN32_MMAP)
 748
 749 #ifndef PROT_READ
 750 #define PROT_READ 1
 751 #define PROT_WRITE 2
 752 #define MAP_PRIVATE 1
 753 #endif
 754
 755 #define mmap git_mmap
 756 #define munmap git_munmap
 757 void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
 758 int git_munmap(void *start, size_t length);
 759
 760 #else /* NO_MMAP || USE_WIN32_MMAP */
 761
 762 #include <sys/mman.h>
 763
 764 #endif /* NO_MMAP || USE_WIN32_MMAP */
 765
 766 #ifdef NO_MMAP
 767
 768 /* This value must be multiple of (pagesize * 2) */
 769 #define DEFAULT_PACKED_GIT_WINDOW_SIZE (1 * 1024 * 1024)
 770
 771 #else /* NO_MMAP */
 772
 773 /* This value must be multiple of (pagesize * 2) */
 774 #define DEFAULT_PACKED_GIT_WINDOW_SIZE \
 775         (sizeof(void*) >= 8 \
 776                 ?  1 * 1024 * 1024 * 1024 \
 777                 : 32 * 1024 * 1024)
 778
 779 #endif /* NO_MMAP */
 780
 781 #ifndef MAP_FAILED
 782 #define MAP_FAILED ((void *)-1)
 783 #endif
 784
 785 #ifdef NO_ST_BLOCKS_IN_STRUCT_STAT
 786 #define on_disk_bytes(st) ((st).st_size)
 787 #else
 788 #define on_disk_bytes(st) ((st).st_blocks * 512)
 789 #endif
 790
 791 #ifdef NEEDS_MODE_TRANSLATION
 792 #undef S_IFMT
 793 #undef S_IFREG
 794 #undef S_IFDIR
 795 #undef S_IFLNK
 796 #undef S_IFBLK
 797 #undef S_IFCHR
 798 #undef S_IFIFO
 799 #undef S_IFSOCK
 800 #define S_IFMT   0170000
 801 #define S_IFREG  0100000
 802 #define S_IFDIR  0040000
 803 #define S_IFLNK  0120000
 804 #define S_IFBLK  0060000
 805 #define S_IFCHR  0020000
 806 #define S_IFIFO  0010000
 807 #define S_IFSOCK 0140000
 808 #ifdef stat
 809 #undef stat
 810 #endif
 811 #define stat(path, buf) git_stat(path, buf)
 812 int git_stat(const char *, struct stat *);
 813 #ifdef fstat
 814 #undef fstat
 815 #endif
 816 #define fstat(fd, buf) git_fstat(fd, buf)
 817 int git_fstat(int, struct stat *);
 818 #ifdef lstat
 819 #undef lstat
 820 #endif
 821 #define lstat(path, buf) git_lstat(path, buf)
 822 int git_lstat(const char *, struct stat *);
 823 #endif
 824
 825 #define DEFAULT_PACKED_GIT_LIMIT \
 826         ((1024L * 1024L) * (size_t)(sizeof(void*) >= 8 ? (32 * 1024L * 1024L) : 256))
 827
 828 #ifdef NO_PREAD
 829 #define pread git_pread
 830 ssize_t git_pread(int fd, void *buf, size_t count, off_t offset);
 831 #endif
 832 /*
 833  * Forward decl that will remind us if its twin in cache.h changes.
 834  * This function is used in compat/pread.c.  But we can't include
 835  * cache.h there.
 836  */
 837 ssize_t read_in_full(int fd, void *buf, size_t count);
 838
 839 #ifdef NO_SETENV
 840 #define setenv gitsetenv
 841 int gitsetenv(const char *, const char *, int);
 842 #endif
 843
 844 #ifdef NO_MKDTEMP
 845 #define mkdtemp gitmkdtemp
 846 char *gitmkdtemp(char *);
 847 #endif
 848
 849 #ifdef NO_UNSETENV
 850 #define unsetenv gitunsetenv
 851 int gitunsetenv(const char *);
 852 #endif
 853
 854 #ifdef NO_STRCASESTR
 855 #define strcasestr gitstrcasestr
 856 char *gitstrcasestr(const char *haystack, const char *needle);
 857 #endif
 858
 859 #ifdef NO_STRLCPY
 860 #define strlcpy gitstrlcpy
 861 size_t gitstrlcpy(char *, const char *, size_t);
 862 #endif
 863
 864 #ifdef NO_STRTOUMAX
 865 #define strtoumax gitstrtoumax
 866 uintmax_t gitstrtoumax(const char *, char **, int);
 867 #define strtoimax gitstrtoimax
 868 intmax_t gitstrtoimax(const char *, char **, int);
 869 #endif
 870
 871 #ifdef NO_HSTRERROR
 872 #define hstrerror githstrerror
 873 const char *githstrerror(int herror);
 874 #endif
 875
 876 #ifdef NO_MEMMEM
 877 #define memmem gitmemmem
 878 void *gitmemmem(const void *haystack, size_t haystacklen,
 879                 const void *needle, size_t needlelen);
 880 #endif
 881
 882 #ifdef OVERRIDE_STRDUP
 883 #ifdef strdup
 884 #undef strdup
 885 #endif
 886 #define strdup gitstrdup
 887 char *gitstrdup(const char *s);
 888 #endif
 889
 890 #ifdef NO_GETPAGESIZE
 891 #define getpagesize() sysconf(_SC_PAGESIZE)
 892 #endif
 893
 894 #ifndef O_CLOEXEC
 895 #define O_CLOEXEC 0
 896 #endif
 897
 898 #ifdef FREAD_READS_DIRECTORIES
 899 # if !defined(SUPPRESS_FOPEN_REDEFINITION)
 900 #  ifdef fopen
 901 #   undef fopen
 902 #  endif
 903 #  define fopen(a,b) git_fopen(a,b)
 904 # endif
 905 FILE *git_fopen(const char*, const char*);
 906 #endif
 907
 908 #ifdef SNPRINTF_RETURNS_BOGUS
 909 #ifdef snprintf
 910 #undef snprintf
 911 #endif
 912 #define snprintf git_snprintf
 913 int git_snprintf(char *str, size_t maxsize,
 914                  const char *format, ...);
 915 #ifdef vsnprintf
 916 #undef vsnprintf
 917 #endif
 918 #define vsnprintf git_vsnprintf
 919 int git_vsnprintf(char *str, size_t maxsize,
 920                   const char *format, va_list ap);
 921 #endif
 922
 923 #ifdef OPEN_RETURNS_EINTR
 924 #undef open
 925 #define open git_open_with_retry
 926 int git_open_with_retry(const char *path, int flag, ...);
 927 #endif
 928
 929 #ifdef __GLIBC_PREREQ
 930 #if __GLIBC_PREREQ(2, 1)
 931 #define HAVE_STRCHRNUL
 932 #endif
 933 #endif
 934
 935 #ifndef HAVE_STRCHRNUL
 936 #define strchrnul gitstrchrnul
 937 static inline char *gitstrchrnul(const char *s, int c)
 938 {
 939         while (*s && *s != c)
 940                 s++;
 941         return (char *)s;
 942 }
 943 #endif
 944
 945 #ifdef NO_INET_PTON
 946 int inet_pton(int af, const char *src, void *dst);
 947 #endif
 948
 949 #ifdef NO_INET_NTOP
 950 const char *inet_ntop(int af, const void *src, char *dst, size_t size);
 951 #endif
 952
 953 #ifdef NO_PTHREADS
 954 #define atexit git_atexit
 955 int git_atexit(void (*handler)(void));
 956 #endif
 957
 958 static inline size_t st_add(size_t a, size_t b)
 959 {
 960         if (unsigned_add_overflows(a, b))
 961                 die("size_t overflow: %"PRIuMAX" + %"PRIuMAX,
 962                     (uintmax_t)a, (uintmax_t)b);
 963         return a + b;
 964 }
 965 #define st_add3(a,b,c)   st_add(st_add((a),(b)),(c))
 966 #define st_add4(a,b,c,d) st_add(st_add3((a),(b),(c)),(d))
 967
 968 static inline size_t st_mult(size_t a, size_t b)
 969 {
 970         if (unsigned_mult_overflows(a, b))
 971                 die("size_t overflow: %"PRIuMAX" * %"PRIuMAX,
 972                     (uintmax_t)a, (uintmax_t)b);
 973         return a * b;
 974 }
 975
 976 static inline size_t st_sub(size_t a, size_t b)
 977 {
 978         if (a < b)
 979                 die("size_t underflow: %"PRIuMAX" - %"PRIuMAX,
 980                     (uintmax_t)a, (uintmax_t)b);
 981         return a - b;
 982 }
 983
 984 static inline size_t st_left_shift(size_t a, unsigned shift)
 985 {
 986         if (unsigned_left_shift_overflows(a, shift))
 987                 die("size_t overflow: %"PRIuMAX" << %u",
 988                     (uintmax_t)a, shift);
 989         return a << shift;
 990 }
 991
 992 static inline unsigned long cast_size_t_to_ulong(size_t a)
 993 {
 994         if (a != (unsigned long)a)
 995                 die("object too large to read on this platform: %"
 996                     PRIuMAX" is cut off to %lu",
 997                     (uintmax_t)a, (unsigned long)a);
 998         return (unsigned long)a;
 999 }
1000
1001 static inline int cast_size_t_to_int(size_t a)
1002 {
1003         if (a > INT_MAX)
1004                 die("number too large to represent as int on this platform: %"PRIuMAX,
1005                     (uintmax_t)a);
1006         return (int)a;
1007 }
1008
1009 /*
1010  * Limit size of IO chunks, because huge chunks only cause pain.  OS X
1011  * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
1012  * the absence of bugs, large chunks can result in bad latencies when
1013  * you decide to kill the process.
1014  *
1015  * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
1016  * that is smaller than that, clip it to SSIZE_MAX, as a call to
1017  * read(2) or write(2) larger than that is allowed to fail.  As the last
1018  * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
1019  * to override this, if the definition of SSIZE_MAX given by the platform
1020  * is broken.
1021  */
1022 #ifndef MAX_IO_SIZE
1023 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
1024 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
1025 #  define MAX_IO_SIZE SSIZE_MAX
1026 # else
1027 #  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
1028 # endif
1029 #endif
1030
1031 #ifdef HAVE_ALLOCA_H
1032 # include <alloca.h>
1033 # define xalloca(size)      (alloca(size))
1034 # define xalloca_free(p)    do {} while (0)
1035 #else
1036 # define xalloca(size)      (xmalloc(size))
1037 # define xalloca_free(p)    (free(p))
1038 #endif
1039 char *xstrdup(const char *str);
1040 void *xmalloc(size_t size);
1041 void *xmallocz(size_t size);
1042 void *xmallocz_gently(size_t size);
1043 void *xmemdupz(const void *data, size_t len);
1044 char *xstrndup(const char *str, size_t len);
1045 void *xrealloc(void *ptr, size_t size);
1046 void *xcalloc(size_t nmemb, size_t size);
1047 void xsetenv(const char *name, const char *value, int overwrite);
1048 void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
1049 const char *mmap_os_err(void);
1050 void *xmmap_gently(void *start, size_t length, int prot, int flags, int fd, off_t offset);
1051 int xopen(const char *path, int flags, ...);
1052 ssize_t xread(int fd, void *buf, size_t len);
1053 ssize_t xwrite(int fd, const void *buf, size_t len);
1054 ssize_t xpread(int fd, void *buf, size_t len, off_t offset);
1055 int xdup(int fd);
1056 FILE *xfopen(const char *path, const char *mode);
1057 FILE *xfdopen(int fd, const char *mode);
1058 int xmkstemp(char *temp_filename);
1059 int xmkstemp_mode(char *temp_filename, int mode);
1060 char *xgetcwd(void);
1061 FILE *fopen_for_writing(const char *path);
1062 FILE *fopen_or_warn(const char *path, const char *mode);
1063
1064 /*
1065  * Like strncmp, but only return zero if s is NUL-terminated and exactly len
1066  * characters long.  If it is not, consider it greater than t.
1067  */
1068 int xstrncmpz(const char *s, const char *t, size_t len);
1069
1070 /*
1071  * FREE_AND_NULL(ptr) is like free(ptr) followed by ptr = NULL. Note
1072  * that ptr is used twice, so don't pass e.g. ptr++.
1073  */
1074 #define FREE_AND_NULL(p) do { free(p); (p) = NULL; } while (0)
1075
1076 #define ALLOC_ARRAY(x, alloc) (x) = xmalloc(st_mult(sizeof(*(x)), (alloc)))
1077 #define CALLOC_ARRAY(x, alloc) (x) = xcalloc((alloc), sizeof(*(x)))
1078 #define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc)))
1079
1080 #define COPY_ARRAY(dst, src, n) copy_array((dst), (src), (n), sizeof(*(dst)) + \
1081         BUILD_ASSERT_OR_ZERO(sizeof(*(dst)) == sizeof(*(src))))
1082 static inline void copy_array(void *dst, const void *src, size_t n, size_t size)
1083 {
1084         if (n)
1085                 memcpy(dst, src, st_mult(size, n));
1086 }
1087
1088 #define MOVE_ARRAY(dst, src, n) move_array((dst), (src), (n), sizeof(*(dst)) + \
1089         BUILD_ASSERT_OR_ZERO(sizeof(*(dst)) == sizeof(*(src))))
1090 static inline void move_array(void *dst, const void *src, size_t n, size_t size)
1091 {
1092         if (n)
1093                 memmove(dst, src, st_mult(size, n));
1094 }
1095
1096 /*
1097  * These functions help you allocate structs with flex arrays, and copy
1098  * the data directly into the array. For example, if you had:
1099  *
1100  *   struct foo {
1101  *     int bar;
1102  *     char name[FLEX_ARRAY];
1103  *   };
1104  *
1105  * you can do:
1106  *
1107  *   struct foo *f;
1108  *   FLEX_ALLOC_MEM(f, name, src, len);
1109  *
1110  * to allocate a "foo" with the contents of "src" in the "name" field.
1111  * The resulting struct is automatically zero'd, and the flex-array field
1112  * is NUL-terminated (whether the incoming src buffer was or not).
1113  *
1114  * The FLEXPTR_* variants operate on structs that don't use flex-arrays,
1115  * but do want to store a pointer to some extra data in the same allocated
1116  * block. For example, if you have:
1117  *
1118  *   struct foo {
1119  *     char *name;
1120  *     int bar;
1121  *   };
1122  *
1123  * you can do:
1124  *
1125  *   struct foo *f;
1126  *   FLEXPTR_ALLOC_STR(f, name, src);
1127  *
1128  * and "name" will point to a block of memory after the struct, which will be
1129  * freed along with the struct (but the pointer can be repointed anywhere).
1130  *
1131  * The *_STR variants accept a string parameter rather than a ptr/len
1132  * combination.
1133  *
1134  * Note that these macros will evaluate the first parameter multiple
1135  * times, and it must be assignable as an lvalue.
1136  */
1137 #define FLEX_ALLOC_MEM(x, flexname, buf, len) do { \
1138         size_t flex_array_len_ = (len); \
1139         (x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
1140         memcpy((void *)(x)->flexname, (buf), flex_array_len_); \
1141 } while (0)
1142 #define FLEXPTR_ALLOC_MEM(x, ptrname, buf, len) do { \
1143         size_t flex_array_len_ = (len); \
1144         (x) = xcalloc(1, st_add3(sizeof(*(x)), flex_array_len_, 1)); \
1145         memcpy((x) + 1, (buf), flex_array_len_); \
1146         (x)->ptrname = (void *)((x)+1); \
1147 } while(0)
1148 #define FLEX_ALLOC_STR(x, flexname, str) \
1149         FLEX_ALLOC_MEM((x), flexname, (str), strlen(str))
1150 #define FLEXPTR_ALLOC_STR(x, ptrname, str) \
1151         FLEXPTR_ALLOC_MEM((x), ptrname, (str), strlen(str))
1152
1153 static inline char *xstrdup_or_null(const char *str)
1154 {
1155         return str ? xstrdup(str) : NULL;
1156 }
1157
1158 static inline size_t xsize_t(off_t len)
1159 {
1160         if (len < 0 || (uintmax_t) len > SIZE_MAX)
1161                 die("Cannot handle files this big");
1162         return (size_t) len;
1163 }
1164
1165 __attribute__((format (printf, 3, 4)))
1166 int xsnprintf(char *dst, size_t max, const char *fmt, ...);
1167
1168 #ifndef HOST_NAME_MAX
1169 #define HOST_NAME_MAX 256
1170 #endif
1171
1172 int xgethostname(char *buf, size_t len);
1173
1174 /* in ctype.c, for kwset users */
1175 extern const unsigned char tolower_trans_tbl[256];
1176
1177 /* Sane ctype - no locale, and works with signed chars */
1178 #undef isascii
1179 #undef isspace
1180 #undef isdigit
1181 #undef isalpha
1182 #undef isalnum
1183 #undef isprint
1184 #undef islower
1185 #undef isupper
1186 #undef tolower
1187 #undef toupper
1188 #undef iscntrl
1189 #undef ispunct
1190 #undef isxdigit
1191
1192 extern const unsigned char sane_ctype[256];
1193 #define GIT_SPACE 0x01
1194 #define GIT_DIGIT 0x02
1195 #define GIT_ALPHA 0x04
1196 #define GIT_GLOB_SPECIAL 0x08
1197 #define GIT_REGEX_SPECIAL 0x10
1198 #define GIT_PATHSPEC_MAGIC 0x20
1199 #define GIT_CNTRL 0x40
1200 #define GIT_PUNCT 0x80
1201 #define sane_istest(x,mask) ((sane_ctype[(unsigned char)(x)] & (mask)) != 0)
1202 #define isascii(x) (((x) & ~0x7f) == 0)
1203 #define isspace(x) sane_istest(x,GIT_SPACE)
1204 #define isdigit(x) sane_istest(x,GIT_DIGIT)
1205 #define isalpha(x) sane_istest(x,GIT_ALPHA)
1206 #define isalnum(x) sane_istest(x,GIT_ALPHA | GIT_DIGIT)
1207 #define isprint(x) ((x) >= 0x20 && (x) <= 0x7e)
1208 #define islower(x) sane_iscase(x, 1)
1209 #define isupper(x) sane_iscase(x, 0)
1210 #define is_glob_special(x) sane_istest(x,GIT_GLOB_SPECIAL)
1211 #define is_regex_special(x) sane_istest(x,GIT_GLOB_SPECIAL | GIT_REGEX_SPECIAL)
1212 #define iscntrl(x) (sane_istest(x,GIT_CNTRL))
1213 #define ispunct(x) sane_istest(x, GIT_PUNCT | GIT_REGEX_SPECIAL | \
1214                 GIT_GLOB_SPECIAL | GIT_PATHSPEC_MAGIC)
1215 #define isxdigit(x) (hexval_table[(unsigned char)(x)] != -1)
1216 #define tolower(x) sane_case((unsigned char)(x), 0x20)
1217 #define toupper(x) sane_case((unsigned char)(x), 0)
1218 #define is_pathspec_magic(x) sane_istest(x,GIT_PATHSPEC_MAGIC)
1219
1220 static inline int sane_case(int x, int high)
1221 {
1222         if (sane_istest(x, GIT_ALPHA))
1223                 x = (x & ~0x20) | high;
1224         return x;
1225 }
1226
1227 static inline int sane_iscase(int x, int is_lower)
1228 {
1229         if (!sane_istest(x, GIT_ALPHA))
1230                 return 0;
1231
1232         if (is_lower)
1233                 return (x & 0x20) != 0;
1234         else
1235                 return (x & 0x20) == 0;
1236 }
1237
1238 /*
1239  * Like skip_prefix, but compare case-insensitively. Note that the comparison
1240  * is done via tolower(), so it is strictly ASCII (no multi-byte characters or
1241  * locale-specific conversions).
1242  */
1243 static inline int skip_iprefix(const char *str, const char *prefix,
1244                                const char **out)
1245 {
1246         do {
1247                 if (!*prefix) {
1248                         *out = str;
1249                         return 1;
1250                 }
1251         } while (tolower(*str++) == tolower(*prefix++));
1252         return 0;
1253 }
1254
1255 static inline int strtoul_ui(char const *s, int base, unsigned int *result)
1256 {
1257         unsigned long ul;
1258         char *p;
1259
1260         errno = 0;
1261         /* negative values would be accepted by strtoul */
1262         if (strchr(s, '-'))
1263                 return -1;
1264         ul = strtoul(s, &p, base);
1265         if (errno || *p || p == s || (unsigned int) ul != ul)
1266                 return -1;
1267         *result = ul;
1268         return 0;
1269 }
1270
1271 static inline int strtol_i(char const *s, int base, int *result)
1272 {
1273         long ul;
1274         char *p;
1275
1276         errno = 0;
1277         ul = strtol(s, &p, base);
1278         if (errno || *p || p == s || (int) ul != ul)
1279                 return -1;
1280         *result = ul;
1281         return 0;
1282 }
1283
1284 void git_stable_qsort(void *base, size_t nmemb, size_t size,
1285                       int(*compar)(const void *, const void *));
1286 #ifdef INTERNAL_QSORT
1287 #define qsort git_stable_qsort
1288 #endif
1289
1290 #define QSORT(base, n, compar) sane_qsort((base), (n), sizeof(*(base)), compar)
1291 static inline void sane_qsort(void *base, size_t nmemb, size_t size,
1292                               int(*compar)(const void *, const void *))
1293 {
1294         if (nmemb > 1)
1295                 qsort(base, nmemb, size, compar);
1296 }
1297
1298 #define STABLE_QSORT(base, n, compar) \
1299         git_stable_qsort((base), (n), sizeof(*(base)), compar)
1300
1301 #ifndef HAVE_ISO_QSORT_S
1302 int git_qsort_s(void *base, size_t nmemb, size_t size,
1303                 int (*compar)(const void *, const void *, void *), void *ctx);
1304 #define qsort_s git_qsort_s
1305 #endif
1306
1307 #define QSORT_S(base, n, compar, ctx) do {                      \
1308         if (qsort_s((base), (n), sizeof(*(base)), compar, ctx)) \
1309                 BUG("qsort_s() failed");                        \
1310 } while (0)
1311
1312 #ifndef REG_STARTEND
1313 #error "Git requires REG_STARTEND support. Compile with NO_REGEX=NeedsStartEnd"
1314 #endif
1315
1316 static inline int regexec_buf(const regex_t *preg, const char *buf, size_t size,
1317                               size_t nmatch, regmatch_t pmatch[], int eflags)
1318 {
1319         assert(nmatch > 0 && pmatch);
1320         pmatch[0].rm_so = 0;
1321         pmatch[0].rm_eo = size;
1322         return regexec(preg, buf, nmatch, pmatch, eflags | REG_STARTEND);
1323 }
1324
1325 #ifndef DIR_HAS_BSD_GROUP_SEMANTICS
1326 # define FORCE_DIR_SET_GID S_ISGID
1327 #else
1328 # define FORCE_DIR_SET_GID 0
1329 #endif
1330
1331 #ifdef NO_NSEC
1332 #undef USE_NSEC
1333 #define ST_CTIME_NSEC(st) 0
1334 #define ST_MTIME_NSEC(st) 0
1335 #else
1336 #ifdef USE_ST_TIMESPEC
1337 #define ST_CTIME_NSEC(st) ((unsigned int)((st).st_ctimespec.tv_nsec))
1338 #define ST_MTIME_NSEC(st) ((unsigned int)((st).st_mtimespec.tv_nsec))
1339 #else
1340 #define ST_CTIME_NSEC(st) ((unsigned int)((st).st_ctim.tv_nsec))
1341 #define ST_MTIME_NSEC(st) ((unsigned int)((st).st_mtim.tv_nsec))
1342 #endif
1343 #endif
1344
1345 #ifdef UNRELIABLE_FSTAT
1346 #define fstat_is_reliable() 0
1347 #else
1348 #define fstat_is_reliable() 1
1349 #endif
1350
1351 #ifndef va_copy
1352 /*
1353  * Since an obvious implementation of va_list would be to make it a
1354  * pointer into the stack frame, a simple assignment will work on
1355  * many systems.  But let's try to be more portable.
1356  */
1357 #ifdef __va_copy
1358 #define va_copy(dst, src) __va_copy(dst, src)
1359 #else
1360 #define va_copy(dst, src) ((dst) = (src))
1361 #endif
1362 #endif
1363
1364 /* usage.c: only to be used for testing BUG() implementation (see test-tool) */
1365 extern int BUG_exit_code;
1366
1367 /* usage.c: if bug() is called we should have a BUG_if_bug() afterwards */
1368 extern int bug_called_must_BUG;
1369
1370 __attribute__((format (printf, 3, 4))) NORETURN
1371 void BUG_fl(const char *file, int line, const char *fmt, ...);
1372 #define BUG(...) BUG_fl(__FILE__, __LINE__, __VA_ARGS__)
1373 __attribute__((format (printf, 3, 4)))
1374 void bug_fl(const char *file, int line, const char *fmt, ...);
1375 #define bug(...) bug_fl(__FILE__, __LINE__, __VA_ARGS__)
1376 #define BUG_if_bug(...) do { \
1377         if (bug_called_must_BUG) \
1378                 BUG_fl(__FILE__, __LINE__, __VA_ARGS__); \
1379 } while (0)
1380
1381 #ifndef FSYNC_METHOD_DEFAULT
1382 #ifdef __APPLE__
1383 #define FSYNC_METHOD_DEFAULT FSYNC_METHOD_WRITEOUT_ONLY
1384 #else
1385 #define FSYNC_METHOD_DEFAULT FSYNC_METHOD_FSYNC
1386 #endif
1387 #endif
1388
1389 enum fsync_action {
1390         FSYNC_WRITEOUT_ONLY,
1391         FSYNC_HARDWARE_FLUSH
1392 };
1393
1394 /*
1395  * Issues an fsync against the specified file according to the specified mode.
1396  *
1397  * FSYNC_WRITEOUT_ONLY attempts to use interfaces available on some operating
1398  * systems to flush the OS cache without issuing a flush command to the storage
1399  * controller. If those interfaces are unavailable, the function fails with
1400  * ENOSYS.
1401  *
1402  * FSYNC_HARDWARE_FLUSH does an OS writeout and hardware flush to ensure that
1403  * changes are durable. It is not expected to fail.
1404  */
1405 int git_fsync(int fd, enum fsync_action action);
1406
1407 /*
1408  * Writes out trace statistics for fsync using the trace2 API.
1409  */
1410 void trace_git_fsync_stats(void);
1411
1412 /*
1413  * Preserves errno, prints a message, but gives no warning for ENOENT.
1414  * Returns 0 on success, which includes trying to unlink an object that does
1415  * not exist.
1416  */
1417 int unlink_or_warn(const char *path);
1418  /*
1419   * Tries to unlink file.  Returns 0 if unlink succeeded
1420   * or the file already didn't exist.  Returns -1 and
1421   * appends a message to err suitable for
1422   * 'error("%s", err->buf)' on error.
1423   */
1424 int unlink_or_msg(const char *file, struct strbuf *err);
1425 /*
1426  * Preserves errno, prints a message, but gives no warning for ENOENT.
1427  * Returns 0 on success, which includes trying to remove a directory that does
1428  * not exist.
1429  */
1430 int rmdir_or_warn(const char *path);
1431 /*
1432  * Calls the correct function out of {unlink,rmdir}_or_warn based on
1433  * the supplied file mode.
1434  */
1435 int remove_or_warn(unsigned int mode, const char *path);
1436
1437 /*
1438  * Call access(2), but warn for any error except "missing file"
1439  * (ENOENT or ENOTDIR).
1440  */
1441 #define ACCESS_EACCES_OK (1U << 0)
1442 int access_or_warn(const char *path, int mode, unsigned flag);
1443 int access_or_die(const char *path, int mode, unsigned flag);
1444
1445 /* Warn on an inaccessible file if errno indicates this is an error */
1446 int warn_on_fopen_errors(const char *path);
1447
1448 /*
1449  * Open with O_NOFOLLOW, or equivalent. Note that the fallback equivalent
1450  * may be racy. Do not use this as protection against an attacker who can
1451  * simultaneously create paths.
1452  */
1453 int open_nofollow(const char *path, int flags);
1454
1455 #ifndef SHELL_PATH
1456 # define SHELL_PATH "/bin/sh"
1457 #endif
1458
1459 #ifndef _POSIX_THREAD_SAFE_FUNCTIONS
1460 static inline void flockfile(FILE *fh)
1461 {
1462         ; /* nothing */
1463 }
1464 static inline void funlockfile(FILE *fh)
1465 {
1466         ; /* nothing */
1467 }
1468 #define getc_unlocked(fh) getc(fh)
1469 #endif
1470
1471 #ifdef FILENO_IS_A_MACRO
1472 int git_fileno(FILE *stream);
1473 # ifndef COMPAT_CODE_FILENO
1474 #  undef fileno
1475 #  define fileno(p) git_fileno(p)
1476 # endif
1477 #endif
1478
1479 #ifdef NEED_ACCESS_ROOT_HANDLER
1480 int git_access(const char *path, int mode);
1481 # ifndef COMPAT_CODE_ACCESS
1482 #  ifdef access
1483 #  undef access
1484 #  endif
1485 #  define access(path, mode) git_access(path, mode)
1486 # endif
1487 #endif
1488
1489 /*
1490  * Our code often opens a path to an optional file, to work on its
1491  * contents when we can successfully open it.  We can ignore a failure
1492  * to open if such an optional file does not exist, but we do want to
1493  * report a failure in opening for other reasons (e.g. we got an I/O
1494  * error, or the file is there, but we lack the permission to open).
1495  *
1496  * Call this function after seeing an error from open() or fopen() to
1497  * see if the errno indicates a missing file that we can safely ignore.
1498  */
1499 static inline int is_missing_file_error(int errno_)
1500 {
1501         return (errno_ == ENOENT || errno_ == ENOTDIR);
1502 }
1503
1504 int cmd_main(int, const char **);
1505
1506 /*
1507  * Intercept all calls to exit() and route them to trace2 to
1508  * optionally emit a message before calling the real exit().
1509  */
1510 int common_exit(const char *file, int line, int code);
1511 #define exit(code) exit(common_exit(__FILE__, __LINE__, (code)))
1512
1513 /*
1514  * You can mark a stack variable with UNLEAK(var) to avoid it being
1515  * reported as a leak by tools like LSAN or valgrind. The argument
1516  * should generally be the variable itself (not its address and not what
1517  * it points to). It's safe to use this on pointers which may already
1518  * have been freed, or on pointers which may still be in use.
1519  *
1520  * Use this _only_ for a variable that leaks by going out of scope at
1521  * program exit (so only from cmd_* functions or their direct helpers).
1522  * Normal functions, especially those which may be called multiple
1523  * times, should actually free their memory. This is only meant as
1524  * an annotation, and does nothing in non-leak-checking builds.
1525  */
1526 #ifdef SUPPRESS_ANNOTATED_LEAKS
1527 void unleak_memory(const void *ptr, size_t len);
1528 #define UNLEAK(var) unleak_memory(&(var), sizeof(var))
1529 #else
1530 #define UNLEAK(var) do {} while (0)
1531 #endif
1532
1533 #define z_const
1534 #include <zlib.h>
1535
1536 #if ZLIB_VERNUM < 0x1290
1537 /*
1538  * This is uncompress2, which is only available in zlib >= 1.2.9
1539  * (released as of early 2017). See compat/zlib-uncompress2.c.
1540  */
1541 int uncompress2(Bytef *dest, uLongf *destLen, const Bytef *source,
1542                 uLong *sourceLen);
1543 #endif
1544
1545 /*
1546  * This include must come after system headers, since it introduces macros that
1547  * replace system names.
1548  */
1549 #include "banned.h"
1550
1551 /*
1552  * container_of - Get the address of an object containing a field.
1553  *
1554  * @ptr: pointer to the field.
1555  * @type: type of the object.
1556  * @member: name of the field within the object.
1557  */
1558 #define container_of(ptr, type, member) \
1559         ((type *) ((char *)(ptr) - offsetof(type, member)))
1560
1561 /*
1562  * helper function for `container_of_or_null' to avoid multiple
1563  * evaluation of @ptr
1564  */
1565 static inline void *container_of_or_null_offset(void *ptr, size_t offset)
1566 {
1567         return ptr ? (char *)ptr - offset : NULL;
1568 }
1569
1570 /*
1571  * like `container_of', but allows returned value to be NULL
1572  */
1573 #define container_of_or_null(ptr, type, member) \
1574         (type *)container_of_or_null_offset(ptr, offsetof(type, member))
1575
1576 /*
1577  * like offsetof(), but takes a pointer to a variable of type which
1578  * contains @member, instead of a specified type.
1579  * @ptr is subject to multiple evaluation since we can't rely on __typeof__
1580  * everywhere.
1581  */
1582 #if defined(__GNUC__) /* clang sets this, too */
1583 #define OFFSETOF_VAR(ptr, member) offsetof(__typeof__(*ptr), member)
1584 #else /* !__GNUC__ */
1585 #define OFFSETOF_VAR(ptr, member) \
1586         ((uintptr_t)&(ptr)->member - (uintptr_t)(ptr))
1587 #endif /* !__GNUC__ */
1588
1589 void sleep_millisec(int millisec);
1590
1591 /*
1592  * Generate len bytes from the system cryptographically secure PRNG.
1593  * Returns 0 on success and -1 on error, setting errno.  The inability to
1594  * satisfy the full request is an error.
1595  */
1596 int csprng_bytes(void *buf, size_t len);
1597
1598 #endif