src/system.h

   1 /* system-dependent definitions for coreutils
   2    Copyright (C) 1989, 1991-2008 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 #include <alloca.h>
  18
  19 /* Include sys/types.h before this file.  */
  20
  21 #if 2 <= __GLIBC__ && 2 <= __GLIBC_MINOR__
  22 # if ! defined _SYS_TYPES_H
  23 you must include <sys/types.h> before including this file
  24 # endif
  25 #endif
  26
  27 #include <sys/stat.h>
  28
  29 #if !defined HAVE_MKFIFO
  30 # define mkfifo(name, mode) mknod (name, (mode) | S_IFIFO, 0)
  31 #endif
  32
  33 #if HAVE_SYS_PARAM_H
  34 # include <sys/param.h>
  35 #endif
  36
  37 #include <unistd.h>
  38
  39 #ifndef STDIN_FILENO
  40 # define STDIN_FILENO 0
  41 #endif
  42
  43 #ifndef STDOUT_FILENO
  44 # define STDOUT_FILENO 1
  45 #endif
  46
  47 #ifndef STDERR_FILENO
  48 # define STDERR_FILENO 2
  49 #endif
  50
  51
  52 /* limits.h must come before pathmax.h because limits.h on some systems
  53    undefs PATH_MAX, whereas pathmax.h sets PATH_MAX.  */
  54 #include <limits.h>
  55
  56 #include "pathmax.h"
  57
  58 #include "configmake.h"
  59
  60 #if TIME_WITH_SYS_TIME
  61 # include <sys/time.h>
  62 # include <time.h>
  63 #else
  64 # if HAVE_SYS_TIME_H
  65 #  include <sys/time.h>
  66 # else
  67 #  include <time.h>
  68 # endif
  69 #endif
  70
  71 /* Since major is a function on SVR4, we can't use `ifndef major'.  */
  72 #if MAJOR_IN_MKDEV
  73 # include <sys/mkdev.h>
  74 # define HAVE_MAJOR
  75 #endif
  76 #if MAJOR_IN_SYSMACROS
  77 # include <sys/sysmacros.h>
  78 # define HAVE_MAJOR
  79 #endif
  80 #ifdef major                    /* Might be defined in sys/types.h.  */
  81 # define HAVE_MAJOR
  82 #endif
  83
  84 #ifndef HAVE_MAJOR
  85 # define major(dev)  (((dev) >> 8) & 0xff)
  86 # define minor(dev)  ((dev) & 0xff)
  87 # define makedev(maj, min)  (((maj) << 8) | (min))
  88 #endif
  89 #undef HAVE_MAJOR
  90
  91 #if ! defined makedev && defined mkdev
  92 # define makedev(maj, min)  mkdev (maj, min)
  93 #endif
  94
  95 /* Don't use bcopy!  Use memmove if source and destination may overlap,
  96    memcpy otherwise.  */
  97
  98 #include <string.h>
  99
 100 #include <errno.h>
 101
 102 /* Some systems don't define the following symbols.  */
 103 #ifndef EDQUOT
 104 # define EDQUOT (-1)
 105 #endif
 106 #ifndef EISDIR
 107 # define EISDIR (-1)
 108 #endif
 109 #ifndef ENOSYS
 110 # define ENOSYS (-1)
 111 #endif
 112 #ifndef ENODATA
 113 # define ENODATA (-1)
 114 #endif
 115
 116 #include <stdbool.h>
 117 #include <stdlib.h>
 118
 119 /* Exit statuses for programs like 'env' that exec other programs.  */
 120 enum
 121 {
 122   EXIT_CANNOT_INVOKE = 126,
 123   EXIT_ENOENT = 127
 124 };
 125
 126 #include "exitfail.h"
 127
 128 /* Set exit_failure to STATUS if that's not the default already.  */
 129 static inline void
 130 initialize_exit_failure (int status)
 131 {
 132   if (status != EXIT_FAILURE)
 133     exit_failure = status;
 134 }
 135
 136 #include <fcntl.h>
 137
 138 #ifndef F_OK
 139 # define F_OK 0
 140 # define X_OK 1
 141 # define W_OK 2
 142 # define R_OK 4
 143 #endif
 144
 145 #include <dirent.h>
 146 #ifndef _D_EXACT_NAMLEN
 147 # define _D_EXACT_NAMLEN(dp) strlen ((dp)->d_name)
 148 #endif
 149
 150 enum
 151 {
 152   NOT_AN_INODE_NUMBER = 0
 153 };
 154
 155 #ifdef D_INO_IN_DIRENT
 156 # define D_INO(dp) (dp)->d_ino
 157 #else
 158 /* Some systems don't have inodes, so fake them to avoid lots of ifdefs.  */
 159 # define D_INO(dp) NOT_AN_INODE_NUMBER
 160 #endif
 161
 162 /* Get or fake the disk device blocksize.
 163    Usually defined by sys/param.h (if at all).  */
 164 #if !defined DEV_BSIZE && defined BSIZE
 165 # define DEV_BSIZE BSIZE
 166 #endif
 167 #if !defined DEV_BSIZE && defined BBSIZE /* SGI */
 168 # define DEV_BSIZE BBSIZE
 169 #endif
 170 #ifndef DEV_BSIZE
 171 # define DEV_BSIZE 4096
 172 #endif
 173
 174 /* Extract or fake data from a `struct stat'.
 175    ST_BLKSIZE: Preferred I/O blocksize for the file, in bytes.
 176    ST_NBLOCKS: Number of blocks in the file, including indirect blocks.
 177    ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS.  */
 178 #ifndef HAVE_STRUCT_STAT_ST_BLOCKS
 179 # define ST_BLKSIZE(statbuf) DEV_BSIZE
 180 # if defined _POSIX_SOURCE || !defined BSIZE /* fileblocks.c uses BSIZE.  */
 181 #  define ST_NBLOCKS(statbuf) \
 182   ((statbuf).st_size / ST_NBLOCKSIZE + ((statbuf).st_size % ST_NBLOCKSIZE != 0))
 183 # else /* !_POSIX_SOURCE && BSIZE */
 184 #  define ST_NBLOCKS(statbuf) \
 185   (S_ISREG ((statbuf).st_mode) \
 186    || S_ISDIR ((statbuf).st_mode) \
 187    ? st_blocks ((statbuf).st_size) : 0)
 188 # endif /* !_POSIX_SOURCE && BSIZE */
 189 #else /* HAVE_STRUCT_STAT_ST_BLOCKS */
 190 /* Some systems, like Sequents, return st_blksize of 0 on pipes.
 191    Also, when running `rsh hpux11-system cat any-file', cat would
 192    determine that the output stream had an st_blksize of 2147421096.
 193    Conversely st_blksize can be 2 GiB (or maybe even larger) with XFS
 194    on 64-bit hosts.  Somewhat arbitrarily, limit the `optimal' block
 195    size to SIZE_MAX / 8 + 1.  (Dividing SIZE_MAX by only 4 wouldn't
 196    suffice, since "cat" sometimes multiplies the result by 4.)  If
 197    anyone knows of a system for which this limit is too small, please
 198    report it as a bug in this code.  */
 199 # define ST_BLKSIZE(statbuf) ((0 < (statbuf).st_blksize \
 200                                && (statbuf).st_blksize <= SIZE_MAX / 8 + 1) \
 201                               ? (statbuf).st_blksize : DEV_BSIZE)
 202 # if defined hpux || defined __hpux__ || defined __hpux
 203 /* HP-UX counts st_blocks in 1024-byte units.
 204    This loses when mixing HP-UX and BSD file systems with NFS.  */
 205 #  define ST_NBLOCKSIZE 1024
 206 # else /* !hpux */
 207 #  if defined _AIX && defined _I386
 208 /* AIX PS/2 counts st_blocks in 4K units.  */
 209 #   define ST_NBLOCKSIZE (4 * 1024)
 210 #  else /* not AIX PS/2 */
 211 #   if defined _CRAY
 212 #    define ST_NBLOCKS(statbuf) \
 213   (S_ISREG ((statbuf).st_mode) \
 214    || S_ISDIR ((statbuf).st_mode) \
 215    ? (statbuf).st_blocks * ST_BLKSIZE(statbuf)/ST_NBLOCKSIZE : 0)
 216 #   endif /* _CRAY */
 217 #  endif /* not AIX PS/2 */
 218 # endif /* !hpux */
 219 #endif /* HAVE_STRUCT_STAT_ST_BLOCKS */
 220
 221 #ifndef ST_NBLOCKS
 222 # define ST_NBLOCKS(statbuf) ((statbuf).st_blocks)
 223 #endif
 224
 225 #ifndef ST_NBLOCKSIZE
 226 # ifdef S_BLKSIZE
 227 #  define ST_NBLOCKSIZE S_BLKSIZE
 228 # else
 229 #  define ST_NBLOCKSIZE 512
 230 # endif
 231 #endif
 232
 233 /* Redirection and wildcarding when done by the utility itself.
 234    Generally a noop, but used in particular for native VMS. */
 235 #ifndef initialize_main
 236 # define initialize_main(ac, av)
 237 #endif
 238
 239 #include "stat-macros.h"
 240
 241 #include "timespec.h"
 242
 243 #include <inttypes.h>
 244
 245 #include <ctype.h>
 246
 247 #if ! (defined isblank || HAVE_DECL_ISBLANK)
 248 # define isblank(c) ((c) == ' ' || (c) == '\t')
 249 #endif
 250
 251 /* ISDIGIT differs from isdigit, as follows:
 252    - Its arg may be any int or unsigned int; it need not be an unsigned char
 253      or EOF.
 254    - It's typically faster.
 255    POSIX says that only '0' through '9' are digits.  Prefer ISDIGIT to
 256    isdigit unless it's important to use the locale's definition
 257    of `digit' even when the host does not conform to POSIX.  */
 258 #define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9)
 259
 260 /* Convert a possibly-signed character to an unsigned character.  This is
 261    a bit safer than casting to unsigned char, since it catches some type
 262    errors that the cast doesn't.  */
 263 static inline unsigned char to_uchar (char ch) { return ch; }
 264
 265 #include <locale.h>
 266
 267 /* Take care of NLS matters.  */
 268
 269 #include "gettext.h"
 270 #if ! ENABLE_NLS
 271 # undef textdomain
 272 # define textdomain(Domainname) /* empty */
 273 # undef bindtextdomain
 274 # define bindtextdomain(Domainname, Dirname) /* empty */
 275 #endif
 276
 277 #define _(msgid) gettext (msgid)
 278 #define N_(msgid) msgid
 279
 280 /* Return a value that pluralizes the same way that N does, in all
 281    languages we know of.  */
 282 static inline unsigned long int
 283 select_plural (uintmax_t n)
 284 {
 285   /* Reduce by a power of ten, but keep it away from zero.  The
 286      gettext manual says 1000000 should be safe.  */
 287   enum { PLURAL_REDUCER = 1000000 };
 288   return (n <= ULONG_MAX ? n : n % PLURAL_REDUCER + PLURAL_REDUCER);
 289 }
 290
 291 #define STREQ(a, b) (strcmp (a, b) == 0)
 292
 293 #if !HAVE_DECL_FREE
 294 void free ();
 295 #endif
 296
 297 #if !HAVE_DECL_MALLOC
 298 char *malloc ();
 299 #endif
 300
 301 #if !HAVE_DECL_MEMCHR
 302 char *memchr ();
 303 #endif
 304
 305 #if !HAVE_DECL_REALLOC
 306 char *realloc ();
 307 #endif
 308
 309 #if !HAVE_DECL_GETENV
 310 char *getenv ();
 311 #endif
 312
 313 #if !HAVE_DECL_LSEEK
 314 off_t lseek ();
 315 #endif
 316
 317 #if !HAVE_DECL_GETLOGIN
 318 char *getlogin ();
 319 #endif
 320
 321 #if !HAVE_DECL_TTYNAME
 322 char *ttyname ();
 323 #endif
 324
 325 #if !HAVE_DECL_GETEUID
 326 uid_t geteuid ();
 327 #endif
 328
 329 #if !HAVE_DECL_GETPWUID
 330 struct passwd *getpwuid ();
 331 #endif
 332
 333 #if !HAVE_DECL_GETGRGID
 334 struct group *getgrgid ();
 335 #endif
 336
 337 #if !HAVE_DECL_GETUID
 338 uid_t getuid ();
 339 #endif
 340
 341 #include "xalloc.h"
 342 #include "verify.h"
 343
 344 /* This is simply a shorthand for the common case in which
 345    the third argument to x2nrealloc would be `sizeof *(P)'.
 346    Ensure that sizeof *(P) is *not* 1.  In that case, it'd be
 347    better to use X2REALLOC, although not strictly necessary.  */
 348 #define X2NREALLOC(P, PN) ((void) verify_true (sizeof *(P) != 1), \
 349                            x2nrealloc (P, PN, sizeof *(P)))
 350
 351 /* Using x2realloc (when appropriate) usually makes your code more
 352    readable than using x2nrealloc, but it also makes it so your
 353    code will malfunction if sizeof *(P) ever becomes 2 or greater.
 354    So use this macro instead of using x2realloc directly.  */
 355 #define X2REALLOC(P, PN) ((void) verify_true (sizeof *(P) == 1), \
 356                           x2realloc (P, PN))
 357
 358 #include "unlocked-io.h"
 359 #include "same-inode.h"
 360
 361 #include "dirname.h"
 362 #include "openat.h"
 363
 364 static inline bool
 365 dot_or_dotdot (char const *file_name)
 366 {
 367   if (file_name[0] == '.')
 368     {
 369       char sep = file_name[(file_name[1] == '.') + 1];
 370       return (! sep || ISSLASH (sep));
 371     }
 372   else
 373     return false;
 374 }
 375
 376 /* A wrapper for readdir so that callers don't see entries for `.' or `..'.  */
 377 static inline struct dirent const *
 378 readdir_ignoring_dot_and_dotdot (DIR *dirp)
 379 {
 380   while (1)
 381     {
 382       struct dirent const *dp = readdir (dirp);
 383       if (dp == NULL || ! dot_or_dotdot (dp->d_name))
 384         return dp;
 385     }
 386 }
 387
 388 /* Return true if DIR is determined to be an empty directory.  */
 389 static inline bool
 390 is_empty_dir (int fd_cwd, char const *dir)
 391 {
 392   DIR *dirp;
 393   struct dirent const *dp;
 394   int saved_errno;
 395   int fd = openat (fd_cwd, dir,
 396                    (O_RDONLY | O_DIRECTORY
 397                     | O_NOCTTY | O_NOFOLLOW | O_NONBLOCK));
 398
 399   if (fd < 0)
 400     return false;
 401
 402   dirp = fdopendir (fd);
 403   if (dirp == NULL)
 404     {
 405       close (fd);
 406       return false;
 407     }
 408
 409   errno = 0;
 410   dp = readdir_ignoring_dot_and_dotdot (dirp);
 411   saved_errno = errno;
 412   closedir (dirp);
 413   if (dp != NULL)
 414     return false;
 415   return saved_errno == 0 ? true : false;
 416 }
 417
 418 /* Factor out some of the common --help and --version processing code.  */
 419
 420 /* These enum values cannot possibly conflict with the option values
 421    ordinarily used by commands, including CHAR_MAX + 1, etc.  Avoid
 422    CHAR_MIN - 1, as it may equal -1, the getopt end-of-options value.  */
 423 enum
 424 {
 425   GETOPT_HELP_CHAR = (CHAR_MIN - 2),
 426   GETOPT_VERSION_CHAR = (CHAR_MIN - 3)
 427 };
 428
 429 #define GETOPT_HELP_OPTION_DECL \
 430   "help", no_argument, NULL, GETOPT_HELP_CHAR
 431 #define GETOPT_VERSION_OPTION_DECL \
 432   "version", no_argument, NULL, GETOPT_VERSION_CHAR
 433 #define GETOPT_SELINUX_CONTEXT_OPTION_DECL \
 434   "context", required_argument, NULL, 'Z'
 435
 436 #define case_GETOPT_HELP_CHAR                   \
 437   case GETOPT_HELP_CHAR:                        \
 438     usage (EXIT_SUCCESS);                       \
 439     break;
 440
 441 /* Program_name must be a literal string.
 442    Usually it is just PROGRAM_NAME.  */
 443 #define USAGE_BUILTIN_WARNING \
 444   _("\n" \
 445 "NOTE: your shell may have its own version of %s, which usually supersedes\n" \
 446 "the version described here.  Please refer to your shell's documentation\n" \
 447 "for details about the options it supports.\n")
 448
 449 #define HELP_OPTION_DESCRIPTION \
 450   _("      --help     display this help and exit\n")
 451 #define VERSION_OPTION_DESCRIPTION \
 452   _("      --version  output version information and exit\n")
 453
 454 #include "closein.h"
 455 #include "closeout.h"
 456 #include "version-etc.h"
 457 #include "propername.h"
 458 /* Define away proper_name (leaving proper_name_utf8, which affects far
 459    fewer programs), since it's not worth the cost of adding ~17KB to
 460    the x86_64 text size of every single program.  This avoids a 40%
 461    (almost ~2MB) increase in the on-disk space utilization for the set
 462    of the 100 binaries. */
 463 #define proper_name(x) (x)
 464
 465 #define case_GETOPT_VERSION_CHAR(Program_name, Authors)                 \
 466   case GETOPT_VERSION_CHAR:                                             \
 467     version_etc (stdout, Program_name, PACKAGE_NAME, VERSION, Authors,  \
 468                  (char *) NULL);                                        \
 469     exit (EXIT_SUCCESS);                                                \
 470     break;
 471
 472 #ifndef MAX
 473 # define MAX(a, b) ((a) > (b) ? (a) : (b))
 474 #endif
 475
 476 #ifndef MIN
 477 # define MIN(a,b) (((a) < (b)) ? (a) : (b))
 478 #endif
 479
 480 #include "intprops.h"
 481
 482 #ifndef SSIZE_MAX
 483 # define SSIZE_MAX TYPE_MAXIMUM (ssize_t)
 484 #endif
 485
 486 #ifndef OFF_T_MIN
 487 # define OFF_T_MIN TYPE_MINIMUM (off_t)
 488 #endif
 489
 490 #ifndef OFF_T_MAX
 491 # define OFF_T_MAX TYPE_MAXIMUM (off_t)
 492 #endif
 493
 494 #ifndef UID_T_MAX
 495 # define UID_T_MAX TYPE_MAXIMUM (uid_t)
 496 #endif
 497
 498 #ifndef GID_T_MAX
 499 # define GID_T_MAX TYPE_MAXIMUM (gid_t)
 500 #endif
 501
 502 #ifndef PID_T_MAX
 503 # define PID_T_MAX TYPE_MAXIMUM (pid_t)
 504 #endif
 505
 506 /* Use this to suppress gcc's `...may be used before initialized' warnings. */
 507 #ifdef lint
 508 # define IF_LINT(Code) Code
 509 #else
 510 # define IF_LINT(Code) /* empty */
 511 #endif
 512
 513 #ifndef __attribute__
 514 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
 515 #  define __attribute__(x) /* empty */
 516 # endif
 517 #endif
 518
 519 #ifndef ATTRIBUTE_NORETURN
 520 # define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
 521 #endif
 522
 523 #ifndef ATTRIBUTE_UNUSED
 524 # define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
 525 #endif
 526
 527 #if defined strdupa
 528 # define ASSIGN_STRDUPA(DEST, S)                \
 529   do { DEST = strdupa (S); } while (0)
 530 #else
 531 # define ASSIGN_STRDUPA(DEST, S)                \
 532   do                                            \
 533     {                                           \
 534       const char *s_ = (S);                     \
 535       size_t len_ = strlen (s_) + 1;            \
 536       char *tmp_dest_ = alloca (len_);          \
 537       DEST = memcpy (tmp_dest_, s_, len_);      \
 538     }                                           \
 539   while (0)
 540 #endif
 541
 542 #ifndef EOVERFLOW
 543 # define EOVERFLOW EINVAL
 544 #endif
 545
 546 #if ! HAVE_SYNC
 547 # define sync() /* empty */
 548 #endif
 549
 550 /* Compute the greatest common divisor of U and V using Euclid's
 551    algorithm.  U and V must be nonzero.  */
 552
 553 static inline size_t
 554 gcd (size_t u, size_t v)
 555 {
 556   do
 557     {
 558       size_t t = u % v;
 559       u = v;
 560       v = t;
 561     }
 562   while (v);
 563
 564   return u;
 565 }
 566
 567 /* Compute the least common multiple of U and V.  U and V must be
 568    nonzero.  There is no overflow checking, so callers should not
 569    specify outlandish sizes.  */
 570
 571 static inline size_t
 572 lcm (size_t u, size_t v)
 573 {
 574   return u * (v / gcd (u, v));
 575 }
 576
 577 /* Return PTR, aligned upward to the next multiple of ALIGNMENT.
 578    ALIGNMENT must be nonzero.  The caller must arrange for ((char *)
 579    PTR) through ((char *) PTR + ALIGNMENT - 1) to be addressable
 580    locations.  */
 581
 582 static inline void *
 583 ptr_align (void const *ptr, size_t alignment)
 584 {
 585   char const *p0 = ptr;
 586   char const *p1 = p0 + alignment - 1;
 587   return (void *) (p1 - (size_t) p1 % alignment);
 588 }
 589
 590 /* If 10*Accum + Digit_val is larger than the maximum value for Type,
 591    then don't update Accum and return false to indicate it would
 592    overflow.  Otherwise, set Accum to that new value and return true.
 593    Verify at compile-time that Type is Accum's type, and that Type is
 594    unsigned.  Accum must be an object, so that we can take its
 595    address.  Accum and Digit_val may be evaluated multiple times.
 596
 597    The "Added check" below is not strictly required, but it causes GCC
 598    to return a nonzero exit status instead of merely a warning
 599    diagnostic, and that is more useful.  */
 600
 601 #define DECIMAL_DIGIT_ACCUMULATE(Accum, Digit_val, Type)                \
 602   (                                                                     \
 603    (void) (&(Accum) == (Type *) NULL),  /* The type matches.  */        \
 604    (void) verify_true (! TYPE_SIGNED (Type)), /* The type is unsigned.  */ \
 605    (void) verify_true (sizeof (Accum) == sizeof (Type)), /* Added check.  */ \
 606    (((Type) -1 / 10 < (Accum)                                           \
 607      || (Type) ((Accum) * 10 + (Digit_val)) < (Accum))                  \
 608     ? false : (((Accum) = (Accum) * 10 + (Digit_val)), true))           \
 609   )
 610
 611 static inline void
 612 emit_bug_reporting_address (void)
 613 {
 614   /* TRANSLATORS: The placeholder indicates the bug-reporting address
 615      for this package.  Please add _another line_ saying
 616      "Report translation bugs to <...>\n" with the address for translation
 617      bugs (typically your translation team's web or email address).  */
 618   printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
 619 }