src/system.h

   1 /* system-dependent definitions for coreutils
   2    Copyright (C) 1989-2012 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 this file _after_ system headers if possible.  */
  18
  19 #include <alloca.h>
  20
  21 /* Include <sys/types.h> before this file.
  22    Note this doesn't warn if we're included
  23    before all system headers.  */
  24
  25 #if 2 < __GLIBC__ || ( 2 == ___GLIBC__ && 2 <= __GLIBC_MINOR__ )
  26 # if ! defined _SYS_TYPES_H
  27 you must include <sys/types.h> before including this file
  28 # endif
  29 #endif
  30
  31 #include <sys/stat.h>
  32
  33 #if !defined HAVE_MKFIFO
  34 # define mkfifo(name, mode) mknod (name, (mode) | S_IFIFO, 0)
  35 #endif
  36
  37 #if HAVE_SYS_PARAM_H
  38 # include <sys/param.h>
  39 #endif
  40
  41 #include <unistd.h>
  42
  43 #include <limits.h>
  44 #ifndef PATH_MAX
  45 # define PATH_MAX 8192
  46 #endif
  47
  48 #include "configmake.h"
  49
  50 #include <sys/time.h>
  51 #include <time.h>
  52
  53 /* Since major is a function on SVR4, we can't use 'ifndef major'.  */
  54 #if MAJOR_IN_MKDEV
  55 # include <sys/mkdev.h>
  56 # define HAVE_MAJOR
  57 #endif
  58 #if MAJOR_IN_SYSMACROS
  59 # include <sys/sysmacros.h>
  60 # define HAVE_MAJOR
  61 #endif
  62 #ifdef major                    /* Might be defined in sys/types.h.  */
  63 # define HAVE_MAJOR
  64 #endif
  65
  66 #ifndef HAVE_MAJOR
  67 # define major(dev)  (((dev) >> 8) & 0xff)
  68 # define minor(dev)  ((dev) & 0xff)
  69 # define makedev(maj, min)  (((maj) << 8) | (min))
  70 #endif
  71 #undef HAVE_MAJOR
  72
  73 #if ! defined makedev && defined mkdev
  74 # define makedev(maj, min)  mkdev (maj, min)
  75 #endif
  76
  77 #include <string.h>
  78 #include <errno.h>
  79
  80 /* Some systems don't define this; POSIX mentions it but says it is
  81    obsolete.  gnulib defines it, but only on native Windows systems,
  82    and there only because MSVC 10 does.  */
  83 #ifndef ENODATA
  84 # define ENODATA (-1)
  85 #endif
  86
  87 #include <stdbool.h>
  88 #include <stdlib.h>
  89 #include "version.h"
  90
  91 /* Exit statuses for programs like 'env' that exec other programs.  */
  92 enum
  93 {
  94   EXIT_TIMEDOUT = 124, /* Time expired before child completed.  */
  95   EXIT_CANCELED = 125, /* Internal error prior to exec attempt.  */
  96   EXIT_CANNOT_INVOKE = 126, /* Program located, but not usable.  */
  97   EXIT_ENOENT = 127 /* Could not find program to exec.  */
  98 };
  99
 100 #include "exitfail.h"
 101
 102 /* Set exit_failure to STATUS if that's not the default already.  */
 103 static inline void
 104 initialize_exit_failure (int status)
 105 {
 106   if (status != EXIT_FAILURE)
 107     exit_failure = status;
 108 }
 109
 110 #include <fcntl.h>
 111
 112 #include <dirent.h>
 113 #ifndef _D_EXACT_NAMLEN
 114 # define _D_EXACT_NAMLEN(dp) strlen ((dp)->d_name)
 115 #endif
 116
 117 enum
 118 {
 119   NOT_AN_INODE_NUMBER = 0
 120 };
 121
 122 #ifdef D_INO_IN_DIRENT
 123 # define D_INO(dp) (dp)->d_ino
 124 #else
 125 /* Some systems don't have inodes, so fake them to avoid lots of ifdefs.  */
 126 # define D_INO(dp) NOT_AN_INODE_NUMBER
 127 #endif
 128
 129 /* include here for SIZE_MAX.  */
 130 #include <inttypes.h>
 131
 132 /* Redirection and wildcarding when done by the utility itself.
 133    Generally a noop, but used in particular for native VMS. */
 134 #ifndef initialize_main
 135 # define initialize_main(ac, av)
 136 #endif
 137
 138 #include "stat-macros.h"
 139
 140 #include "timespec.h"
 141
 142 #include <ctype.h>
 143
 144 /* ISDIGIT differs from isdigit, as follows:
 145    - Its arg may be any int or unsigned int; it need not be an unsigned char
 146      or EOF.
 147    - It's typically faster.
 148    POSIX says that only '0' through '9' are digits.  Prefer ISDIGIT to
 149    isdigit unless it's important to use the locale's definition
 150    of 'digit' even when the host does not conform to POSIX.  */
 151 #define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9)
 152
 153 /* Convert a possibly-signed character to an unsigned character.  This is
 154    a bit safer than casting to unsigned char, since it catches some type
 155    errors that the cast doesn't.  */
 156 static inline unsigned char to_uchar (char ch) { return ch; }
 157
 158 #include <locale.h>
 159
 160 /* Take care of NLS matters.  */
 161
 162 #include "gettext.h"
 163 #if ! ENABLE_NLS
 164 # undef textdomain
 165 # define textdomain(Domainname) /* empty */
 166 # undef bindtextdomain
 167 # define bindtextdomain(Domainname, Dirname) /* empty */
 168 #endif
 169
 170 #define _(msgid) gettext (msgid)
 171 #define N_(msgid) msgid
 172
 173 /* Return a value that pluralizes the same way that N does, in all
 174    languages we know of.  */
 175 static inline unsigned long int
 176 select_plural (uintmax_t n)
 177 {
 178   /* Reduce by a power of ten, but keep it away from zero.  The
 179      gettext manual says 1000000 should be safe.  */
 180   enum { PLURAL_REDUCER = 1000000 };
 181   return (n <= ULONG_MAX ? n : n % PLURAL_REDUCER + PLURAL_REDUCER);
 182 }
 183
 184 #define STREQ(a, b) (strcmp (a, b) == 0)
 185 #define STREQ_LEN(a, b, n) (strncmp (a, b, n) == 0)
 186 #define STRPREFIX(a, b) (strncmp(a, b, strlen (b)) == 0)
 187
 188 /* Just like strncmp, but the second argument must be a literal string
 189    and you don't specify the length;  that comes from the literal.  */
 190 #define STRNCMP_LIT(s, literal) \
 191   strncmp (s, "" literal "", sizeof (literal) - 1)
 192
 193 #if !HAVE_DECL_GETLOGIN
 194 char *getlogin ();
 195 #endif
 196
 197 #if !HAVE_DECL_TTYNAME
 198 char *ttyname ();
 199 #endif
 200
 201 #if !HAVE_DECL_GETEUID
 202 uid_t geteuid ();
 203 #endif
 204
 205 #if !HAVE_DECL_GETPWUID
 206 struct passwd *getpwuid ();
 207 #endif
 208
 209 #if !HAVE_DECL_GETGRGID
 210 struct group *getgrgid ();
 211 #endif
 212
 213 /* Interix has replacements for getgr{gid,nam,ent}, that don't
 214    query the domain controller for group members when not required.
 215    This speeds up the calls tremendously (<1 ms vs. >3 s). */
 216 /* To protect any system that could provide _nomembers functions
 217    other than interix, check for HAVE_SETGROUPS, as interix is
 218    one of the very few (the only?) platform that lacks it */
 219 #if ! HAVE_SETGROUPS
 220 # if HAVE_GETGRGID_NOMEMBERS
 221 #  define getgrgid(gid) getgrgid_nomembers(gid)
 222 # endif
 223 # if HAVE_GETGRNAM_NOMEMBERS
 224 #  define getgrnam(nam) getgrnam_nomembers(nam)
 225 # endif
 226 # if HAVE_GETGRENT_NOMEMBERS
 227 #  define getgrent() getgrent_nomembers()
 228 # endif
 229 #endif
 230
 231 #if !HAVE_DECL_GETUID
 232 uid_t getuid ();
 233 #endif
 234
 235 #include "xalloc.h"
 236 #include "verify.h"
 237
 238 /* This is simply a shorthand for the common case in which
 239    the third argument to x2nrealloc would be 'sizeof *(P)'.
 240    Ensure that sizeof *(P) is *not* 1.  In that case, it'd be
 241    better to use X2REALLOC, although not strictly necessary.  */
 242 #define X2NREALLOC(P, PN) ((void) verify_true (sizeof *(P) != 1), \
 243                            x2nrealloc (P, PN, sizeof *(P)))
 244
 245 /* Using x2realloc (when appropriate) usually makes your code more
 246    readable than using x2nrealloc, but it also makes it so your
 247    code will malfunction if sizeof *(P) ever becomes 2 or greater.
 248    So use this macro instead of using x2realloc directly.  */
 249 #define X2REALLOC(P, PN) ((void) verify_true (sizeof *(P) == 1), \
 250                           x2realloc (P, PN))
 251
 252 #include "unlocked-io.h"
 253 #include "same-inode.h"
 254
 255 #include "dirname.h"
 256 #include "openat.h"
 257
 258 static inline bool
 259 dot_or_dotdot (char const *file_name)
 260 {
 261   if (file_name[0] == '.')
 262     {
 263       char sep = file_name[(file_name[1] == '.') + 1];
 264       return (! sep || ISSLASH (sep));
 265     }
 266   else
 267     return false;
 268 }
 269
 270 /* A wrapper for readdir so that callers don't see entries for '.' or '..'.  */
 271 static inline struct dirent const *
 272 readdir_ignoring_dot_and_dotdot (DIR *dirp)
 273 {
 274   while (1)
 275     {
 276       struct dirent const *dp = readdir (dirp);
 277       if (dp == NULL || ! dot_or_dotdot (dp->d_name))
 278         return dp;
 279     }
 280 }
 281
 282 /* Return true if DIR is determined to be an empty directory.  */
 283 static inline bool
 284 is_empty_dir (int fd_cwd, char const *dir)
 285 {
 286   DIR *dirp;
 287   struct dirent const *dp;
 288   int saved_errno;
 289   int fd = openat (fd_cwd, dir,
 290                    (O_RDONLY | O_DIRECTORY
 291                     | O_NOCTTY | O_NOFOLLOW | O_NONBLOCK));
 292
 293   if (fd < 0)
 294     return false;
 295
 296   dirp = fdopendir (fd);
 297   if (dirp == NULL)
 298     {
 299       close (fd);
 300       return false;
 301     }
 302
 303   errno = 0;
 304   dp = readdir_ignoring_dot_and_dotdot (dirp);
 305   saved_errno = errno;
 306   closedir (dirp);
 307   if (dp != NULL)
 308     return false;
 309   return saved_errno == 0 ? true : false;
 310 }
 311
 312 /* Factor out some of the common --help and --version processing code.  */
 313
 314 /* These enum values cannot possibly conflict with the option values
 315    ordinarily used by commands, including CHAR_MAX + 1, etc.  Avoid
 316    CHAR_MIN - 1, as it may equal -1, the getopt end-of-options value.  */
 317 enum
 318 {
 319   GETOPT_HELP_CHAR = (CHAR_MIN - 2),
 320   GETOPT_VERSION_CHAR = (CHAR_MIN - 3)
 321 };
 322
 323 #define GETOPT_HELP_OPTION_DECL \
 324   "help", no_argument, NULL, GETOPT_HELP_CHAR
 325 #define GETOPT_VERSION_OPTION_DECL \
 326   "version", no_argument, NULL, GETOPT_VERSION_CHAR
 327 #define GETOPT_SELINUX_CONTEXT_OPTION_DECL \
 328   "context", required_argument, NULL, 'Z'
 329
 330 #define case_GETOPT_HELP_CHAR                   \
 331   case GETOPT_HELP_CHAR:                        \
 332     usage (EXIT_SUCCESS);                       \
 333     break;
 334
 335 /* Program_name must be a literal string.
 336    Usually it is just PROGRAM_NAME.  */
 337 #define USAGE_BUILTIN_WARNING \
 338   _("\n" \
 339 "NOTE: your shell may have its own version of %s, which usually supersedes\n" \
 340 "the version described here.  Please refer to your shell's documentation\n" \
 341 "for details about the options it supports.\n")
 342
 343 #define HELP_OPTION_DESCRIPTION \
 344   _("      --help     display this help and exit\n")
 345 #define VERSION_OPTION_DESCRIPTION \
 346   _("      --version  output version information and exit\n")
 347
 348 #include "closein.h"
 349 #include "closeout.h"
 350
 351 #define emit_bug_reporting_address unused__emit_bug_reporting_address
 352 #include "version-etc.h"
 353 #undef emit_bug_reporting_address
 354
 355 #include "propername.h"
 356 /* Define away proper_name (leaving proper_name_utf8, which affects far
 357    fewer programs), since it's not worth the cost of adding ~17KB to
 358    the x86_64 text size of every single program.  This avoids a 40%
 359    (almost ~2MB) increase in the on-disk space utilization for the set
 360    of the 100 binaries. */
 361 #define proper_name(x) (x)
 362
 363 #include "progname.h"
 364
 365 #define case_GETOPT_VERSION_CHAR(Program_name, Authors)                 \
 366   case GETOPT_VERSION_CHAR:                                             \
 367     version_etc (stdout, Program_name, PACKAGE_NAME, Version, Authors,  \
 368                  (char *) NULL);                                        \
 369     exit (EXIT_SUCCESS);                                                \
 370     break;
 371
 372 #ifndef MAX
 373 # define MAX(a, b) ((a) > (b) ? (a) : (b))
 374 #endif
 375
 376 #ifndef MIN
 377 # define MIN(a,b) (((a) < (b)) ? (a) : (b))
 378 #endif
 379
 380 #include "intprops.h"
 381
 382 #ifndef SSIZE_MAX
 383 # define SSIZE_MAX TYPE_MAXIMUM (ssize_t)
 384 #endif
 385
 386 #ifndef OFF_T_MIN
 387 # define OFF_T_MIN TYPE_MINIMUM (off_t)
 388 #endif
 389
 390 #ifndef OFF_T_MAX
 391 # define OFF_T_MAX TYPE_MAXIMUM (off_t)
 392 #endif
 393
 394 #ifndef UID_T_MAX
 395 # define UID_T_MAX TYPE_MAXIMUM (uid_t)
 396 #endif
 397
 398 #ifndef GID_T_MAX
 399 # define GID_T_MAX TYPE_MAXIMUM (gid_t)
 400 #endif
 401
 402 #ifndef PID_T_MAX
 403 # define PID_T_MAX TYPE_MAXIMUM (pid_t)
 404 #endif
 405
 406 /* Use this to suppress gcc's '...may be used before initialized' warnings. */
 407 #ifdef lint
 408 # define IF_LINT(Code) Code
 409 #else
 410 # define IF_LINT(Code) /* empty */
 411 #endif
 412
 413 #ifndef __attribute__
 414 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
 415 #  define __attribute__(x) /* empty */
 416 # endif
 417 #endif
 418
 419 #ifndef ATTRIBUTE_NORETURN
 420 # define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
 421 #endif
 422
 423 #ifndef ATTRIBUTE_UNUSED
 424 # define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
 425 #endif
 426
 427 /* The warn_unused_result attribute appeared first in gcc-3.4.0 */
 428 #undef ATTRIBUTE_WARN_UNUSED_RESULT
 429 #if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
 430 # define ATTRIBUTE_WARN_UNUSED_RESULT /* empty */
 431 #else
 432 # define ATTRIBUTE_WARN_UNUSED_RESULT __attribute__ ((__warn_unused_result__))
 433 #endif
 434
 435 #if defined strdupa
 436 # define ASSIGN_STRDUPA(DEST, S)                \
 437   do { DEST = strdupa (S); } while (0)
 438 #else
 439 # define ASSIGN_STRDUPA(DEST, S)                \
 440   do                                            \
 441     {                                           \
 442       const char *s_ = (S);                     \
 443       size_t len_ = strlen (s_) + 1;            \
 444       char *tmp_dest_ = alloca (len_);          \
 445       DEST = memcpy (tmp_dest_, s_, len_);      \
 446     }                                           \
 447   while (0)
 448 #endif
 449
 450 #if ! HAVE_SYNC
 451 # define sync() /* empty */
 452 #endif
 453
 454 /* Compute the greatest common divisor of U and V using Euclid's
 455    algorithm.  U and V must be nonzero.  */
 456
 457 static inline size_t _GL_ATTRIBUTE_CONST
 458 gcd (size_t u, size_t v)
 459 {
 460   do
 461     {
 462       size_t t = u % v;
 463       u = v;
 464       v = t;
 465     }
 466   while (v);
 467
 468   return u;
 469 }
 470
 471 /* Compute the least common multiple of U and V.  U and V must be
 472    nonzero.  There is no overflow checking, so callers should not
 473    specify outlandish sizes.  */
 474
 475 static inline size_t _GL_ATTRIBUTE_CONST
 476 lcm (size_t u, size_t v)
 477 {
 478   return u * (v / gcd (u, v));
 479 }
 480
 481 /* Return PTR, aligned upward to the next multiple of ALIGNMENT.
 482    ALIGNMENT must be nonzero.  The caller must arrange for ((char *)
 483    PTR) through ((char *) PTR + ALIGNMENT - 1) to be addressable
 484    locations.  */
 485
 486 static inline void *
 487 ptr_align (void const *ptr, size_t alignment)
 488 {
 489   char const *p0 = ptr;
 490   char const *p1 = p0 + alignment - 1;
 491   return (void *) (p1 - (size_t) p1 % alignment);
 492 }
 493
 494 /* Return whether the buffer consists entirely of NULs.
 495    Note the word after the buffer must be non NUL. */
 496
 497 static inline bool _GL_ATTRIBUTE_PURE
 498 is_nul (const char *buf, size_t bufsize)
 499 {
 500   typedef uintptr_t word;
 501
 502   /* Find first nonzero *word*, or the word with the sentinel.  */
 503   word *wp = (word *) buf;
 504   while (*wp++ == 0)
 505     continue;
 506
 507   /* Find the first nonzero *byte*, or the sentinel.  */
 508   char *cp = (char *) (wp - 1);
 509   while (*cp++ == 0)
 510     continue;
 511
 512   return cp > buf + bufsize;
 513 }
 514
 515 /* If 10*Accum + Digit_val is larger than the maximum value for Type,
 516    then don't update Accum and return false to indicate it would
 517    overflow.  Otherwise, set Accum to that new value and return true.
 518    Verify at compile-time that Type is Accum's type, and that Type is
 519    unsigned.  Accum must be an object, so that we can take its
 520    address.  Accum and Digit_val may be evaluated multiple times.
 521
 522    The "Added check" below is not strictly required, but it causes GCC
 523    to return a nonzero exit status instead of merely a warning
 524    diagnostic, and that is more useful.  */
 525
 526 #define DECIMAL_DIGIT_ACCUMULATE(Accum, Digit_val, Type)                \
 527   (                                                                     \
 528    (void) (&(Accum) == (Type *) NULL),  /* The type matches.  */        \
 529    (void) verify_true (! TYPE_SIGNED (Type)), /* The type is unsigned.  */ \
 530    (void) verify_true (sizeof (Accum) == sizeof (Type)), /* Added check.  */ \
 531    (((Type) -1 / 10 < (Accum)                                           \
 532      || (Type) ((Accum) * 10 + (Digit_val)) < (Accum))                  \
 533     ? false : (((Accum) = (Accum) * 10 + (Digit_val)), true))           \
 534   )
 535
 536 static inline void
 537 emit_size_note (void)
 538 {
 539   fputs (_("\n\
 540 SIZE is an integer and optional unit (example: 10M is 10*1024*1024).  Units\n\
 541 are K, M, G, T, P, E, Z, Y (powers of 1024) or KB, MB, ... (powers of 1000).\n\
 542 "), stdout);
 543 }
 544
 545 static inline void
 546 emit_blocksize_note (char const *program)
 547 {
 548   printf (_("\n\
 549 Display values are in units of the first available SIZE from --block-size,\n\
 550 and the %s_BLOCK_SIZE, BLOCK_SIZE and BLOCKSIZE environment variables.\n\
 551 Otherwise, units default to 1024 bytes (or 512 if POSIXLY_CORRECT is set).\n\
 552 "), program);
 553 }
 554
 555 static inline void
 556 emit_ancillary_info (void)
 557 {
 558   printf (_("\nReport %s bugs to %s\n"), last_component (program_name),
 559           PACKAGE_BUGREPORT);
 560   printf (_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
 561   fputs (_("General help using GNU software: <http://www.gnu.org/gethelp/>\n"),
 562          stdout);
 563   /* Don't output this redundant message for English locales.
 564      Note we still output for 'C' so that it gets included in the man page.  */
 565   const char *lc_messages = setlocale (LC_MESSAGES, NULL);
 566   if (lc_messages && STRNCMP_LIT (lc_messages, "en_"))
 567     {
 568       /* TRANSLATORS: Replace LANG_CODE in this URL with your language code
 569          <http://translationproject.org/team/LANG_CODE.html> to form one of
 570          the URLs at http://translationproject.org/team/.  Otherwise, replace
 571          the entire URL with your translation team's email address.  */
 572       printf (_("Report %s translation bugs to "
 573                 "<http://translationproject.org/team/>\n"),
 574                 last_component (program_name));
 575     }
 576   printf (_("For complete documentation, run: "
 577             "info coreutils '%s invocation'\n"), last_component (program_name));
 578 }
 579
 580 static inline void
 581 emit_try_help (void)
 582 {
 583   fprintf (stderr, _("Try '%s --help' for more information.\n"), program_name);
 584 }
 585
 586 #include "inttostr.h"
 587
 588 static inline char *
 589 timetostr (time_t t, char *buf)
 590 {
 591   return (TYPE_SIGNED (time_t)
 592           ? imaxtostr (t, buf)
 593           : umaxtostr (t, buf));
 594 }
 595
 596 static inline char *
 597 bad_cast (char const *s)
 598 {
 599   return (char *) s;
 600 }
 601
 602 void usage (int status) ATTRIBUTE_NORETURN;
 603
 604 #define emit_cycle_warning(file_name)   \
 605   do                                    \
 606     {                                   \
 607       error (0, 0, _("\
 608 WARNING: Circular directory structure.\n\
 609 This almost certainly means that you have a corrupted file system.\n\
 610 NOTIFY YOUR SYSTEM MANAGER.\n\
 611 The following directory is part of the cycle:\n  %s\n"), \
 612              quote (file_name));        \
 613     }                                   \
 614   while (0)
 615
 616 #ifndef ARRAY_CARDINALITY
 617 # define ARRAY_CARDINALITY(Array) (sizeof (Array) / sizeof *(Array))
 618 #endif