src/system.h

   1 /* system-dependent definitions for coreutils
   2    Copyright (C) 1989, 1991-2011 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 /* Don't use bcopy!  Use memmove if source and destination may overlap,
  78    memcpy otherwise.  */
  79
  80 #include <string.h>
  81
  82 #include <errno.h>
  83
  84 /* Some systems don't define this; POSIX mentions it but says it is
  85    obsolete, so gnulib does not provide it either.  */
  86 #ifndef ENODATA
  87 # define ENODATA (-1)
  88 #endif
  89
  90 #include <stdbool.h>
  91 #include <stdlib.h>
  92 #include "version.h"
  93
  94 /* Exit statuses for programs like 'env' that exec other programs.  */
  95 enum
  96 {
  97   EXIT_TIMEDOUT = 124, /* Time expired before child completed.  */
  98   EXIT_CANCELED = 125, /* Internal error prior to exec attempt.  */
  99   EXIT_CANNOT_INVOKE = 126, /* Program located, but not usable.  */
 100   EXIT_ENOENT = 127 /* Could not find program to exec.  */
 101 };
 102
 103 #include "exitfail.h"
 104
 105 /* Set exit_failure to STATUS if that's not the default already.  */
 106 static inline void
 107 initialize_exit_failure (int status)
 108 {
 109   if (status != EXIT_FAILURE)
 110     exit_failure = status;
 111 }
 112
 113 #include <fcntl.h>
 114
 115 #include <dirent.h>
 116 #ifndef _D_EXACT_NAMLEN
 117 # define _D_EXACT_NAMLEN(dp) strlen ((dp)->d_name)
 118 #endif
 119
 120 enum
 121 {
 122   NOT_AN_INODE_NUMBER = 0
 123 };
 124
 125 #ifdef D_INO_IN_DIRENT
 126 # define D_INO(dp) (dp)->d_ino
 127 #else
 128 /* Some systems don't have inodes, so fake them to avoid lots of ifdefs.  */
 129 # define D_INO(dp) NOT_AN_INODE_NUMBER
 130 #endif
 131
 132 /* include here for SIZE_MAX.  */
 133 #include <inttypes.h>
 134
 135 /* Redirection and wildcarding when done by the utility itself.
 136    Generally a noop, but used in particular for native VMS. */
 137 #ifndef initialize_main
 138 # define initialize_main(ac, av)
 139 #endif
 140
 141 #include "stat-macros.h"
 142
 143 #include "timespec.h"
 144
 145 #include <ctype.h>
 146
 147 /* ISDIGIT differs from isdigit, as follows:
 148    - Its arg may be any int or unsigned int; it need not be an unsigned char
 149      or EOF.
 150    - It's typically faster.
 151    POSIX says that only '0' through '9' are digits.  Prefer ISDIGIT to
 152    isdigit unless it's important to use the locale's definition
 153    of `digit' even when the host does not conform to POSIX.  */
 154 #define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9)
 155
 156 /* Convert a possibly-signed character to an unsigned character.  This is
 157    a bit safer than casting to unsigned char, since it catches some type
 158    errors that the cast doesn't.  */
 159 static inline unsigned char to_uchar (char ch) { return ch; }
 160
 161 #include <locale.h>
 162
 163 /* Take care of NLS matters.  */
 164
 165 #include "gettext.h"
 166 #if ! ENABLE_NLS
 167 # undef textdomain
 168 # define textdomain(Domainname) /* empty */
 169 # undef bindtextdomain
 170 # define bindtextdomain(Domainname, Dirname) /* empty */
 171 #endif
 172
 173 #define _(msgid) gettext (msgid)
 174 #define N_(msgid) msgid
 175
 176 /* Return a value that pluralizes the same way that N does, in all
 177    languages we know of.  */
 178 static inline unsigned long int
 179 select_plural (uintmax_t n)
 180 {
 181   /* Reduce by a power of ten, but keep it away from zero.  The
 182      gettext manual says 1000000 should be safe.  */
 183   enum { PLURAL_REDUCER = 1000000 };
 184   return (n <= ULONG_MAX ? n : n % PLURAL_REDUCER + PLURAL_REDUCER);
 185 }
 186
 187 #define STREQ(a, b) (strcmp (a, b) == 0)
 188 #define STREQ_LEN(a, b, n) (strncmp (a, b, n) == 0)
 189 #define STRPREFIX(a, b) (strncmp(a, b, strlen (b)) == 0)
 190
 191 /* Just like strncmp, but the first argument must be a literal string
 192    and you don't specify the length.  */
 193 #define STRNCMP_LIT(s, literal) \
 194   strncmp (s, "" literal "", sizeof (literal) - 1)
 195
 196 #if !HAVE_DECL_GETLOGIN
 197 char *getlogin ();
 198 #endif
 199
 200 #if !HAVE_DECL_TTYNAME
 201 char *ttyname ();
 202 #endif
 203
 204 #if !HAVE_DECL_GETEUID
 205 uid_t geteuid ();
 206 #endif
 207
 208 #if !HAVE_DECL_GETPWUID
 209 struct passwd *getpwuid ();
 210 #endif
 211
 212 #if !HAVE_DECL_GETGRGID
 213 struct group *getgrgid ();
 214 #endif
 215
 216 #if !HAVE_DECL_GETUID
 217 uid_t getuid ();
 218 #endif
 219
 220 #include "xalloc.h"
 221 #include "verify.h"
 222
 223 /* This is simply a shorthand for the common case in which
 224    the third argument to x2nrealloc would be `sizeof *(P)'.
 225    Ensure that sizeof *(P) is *not* 1.  In that case, it'd be
 226    better to use X2REALLOC, although not strictly necessary.  */
 227 #define X2NREALLOC(P, PN) ((void) verify_true (sizeof *(P) != 1), \
 228                            x2nrealloc (P, PN, sizeof *(P)))
 229
 230 /* Using x2realloc (when appropriate) usually makes your code more
 231    readable than using x2nrealloc, but it also makes it so your
 232    code will malfunction if sizeof *(P) ever becomes 2 or greater.
 233    So use this macro instead of using x2realloc directly.  */
 234 #define X2REALLOC(P, PN) ((void) verify_true (sizeof *(P) == 1), \
 235                           x2realloc (P, PN))
 236
 237 #include "unlocked-io.h"
 238 #include "same-inode.h"
 239
 240 #include "dirname.h"
 241 #include "openat.h"
 242
 243 static inline bool
 244 dot_or_dotdot (char const *file_name)
 245 {
 246   if (file_name[0] == '.')
 247     {
 248       char sep = file_name[(file_name[1] == '.') + 1];
 249       return (! sep || ISSLASH (sep));
 250     }
 251   else
 252     return false;
 253 }
 254
 255 /* A wrapper for readdir so that callers don't see entries for `.' or `..'.  */
 256 static inline struct dirent const *
 257 readdir_ignoring_dot_and_dotdot (DIR *dirp)
 258 {
 259   while (1)
 260     {
 261       struct dirent const *dp = readdir (dirp);
 262       if (dp == NULL || ! dot_or_dotdot (dp->d_name))
 263         return dp;
 264     }
 265 }
 266
 267 /* Return true if DIR is determined to be an empty directory.  */
 268 static inline bool
 269 is_empty_dir (int fd_cwd, char const *dir)
 270 {
 271   DIR *dirp;
 272   struct dirent const *dp;
 273   int saved_errno;
 274   int fd = openat (fd_cwd, dir,
 275                    (O_RDONLY | O_DIRECTORY
 276                     | O_NOCTTY | O_NOFOLLOW | O_NONBLOCK));
 277
 278   if (fd < 0)
 279     return false;
 280
 281   dirp = fdopendir (fd);
 282   if (dirp == NULL)
 283     {
 284       close (fd);
 285       return false;
 286     }
 287
 288   errno = 0;
 289   dp = readdir_ignoring_dot_and_dotdot (dirp);
 290   saved_errno = errno;
 291   closedir (dirp);
 292   if (dp != NULL)
 293     return false;
 294   return saved_errno == 0 ? true : false;
 295 }
 296
 297 /* Factor out some of the common --help and --version processing code.  */
 298
 299 /* These enum values cannot possibly conflict with the option values
 300    ordinarily used by commands, including CHAR_MAX + 1, etc.  Avoid
 301    CHAR_MIN - 1, as it may equal -1, the getopt end-of-options value.  */
 302 enum
 303 {
 304   GETOPT_HELP_CHAR = (CHAR_MIN - 2),
 305   GETOPT_VERSION_CHAR = (CHAR_MIN - 3)
 306 };
 307
 308 #define GETOPT_HELP_OPTION_DECL \
 309   "help", no_argument, NULL, GETOPT_HELP_CHAR
 310 #define GETOPT_VERSION_OPTION_DECL \
 311   "version", no_argument, NULL, GETOPT_VERSION_CHAR
 312 #define GETOPT_SELINUX_CONTEXT_OPTION_DECL \
 313   "context", required_argument, NULL, 'Z'
 314
 315 #define case_GETOPT_HELP_CHAR                   \
 316   case GETOPT_HELP_CHAR:                        \
 317     usage (EXIT_SUCCESS);                       \
 318     break;
 319
 320 /* Program_name must be a literal string.
 321    Usually it is just PROGRAM_NAME.  */
 322 #define USAGE_BUILTIN_WARNING \
 323   _("\n" \
 324 "NOTE: your shell may have its own version of %s, which usually supersedes\n" \
 325 "the version described here.  Please refer to your shell's documentation\n" \
 326 "for details about the options it supports.\n")
 327
 328 #define HELP_OPTION_DESCRIPTION \
 329   _("      --help     display this help and exit\n")
 330 #define VERSION_OPTION_DESCRIPTION \
 331   _("      --version  output version information and exit\n")
 332
 333 #include "closein.h"
 334 #include "closeout.h"
 335
 336 #define emit_bug_reporting_address unused__emit_bug_reporting_address
 337 #include "version-etc.h"
 338 #undef emit_bug_reporting_address
 339
 340 #include "propername.h"
 341 /* Define away proper_name (leaving proper_name_utf8, which affects far
 342    fewer programs), since it's not worth the cost of adding ~17KB to
 343    the x86_64 text size of every single program.  This avoids a 40%
 344    (almost ~2MB) increase in the on-disk space utilization for the set
 345    of the 100 binaries. */
 346 #define proper_name(x) (x)
 347
 348 #include "progname.h"
 349
 350 #define case_GETOPT_VERSION_CHAR(Program_name, Authors)                 \
 351   case GETOPT_VERSION_CHAR:                                             \
 352     version_etc (stdout, Program_name, PACKAGE_NAME, Version, Authors,  \
 353                  (char *) NULL);                                        \
 354     exit (EXIT_SUCCESS);                                                \
 355     break;
 356
 357 #ifndef MAX
 358 # define MAX(a, b) ((a) > (b) ? (a) : (b))
 359 #endif
 360
 361 #ifndef MIN
 362 # define MIN(a,b) (((a) < (b)) ? (a) : (b))
 363 #endif
 364
 365 #include "intprops.h"
 366
 367 #ifndef SSIZE_MAX
 368 # define SSIZE_MAX TYPE_MAXIMUM (ssize_t)
 369 #endif
 370
 371 #ifndef OFF_T_MIN
 372 # define OFF_T_MIN TYPE_MINIMUM (off_t)
 373 #endif
 374
 375 #ifndef OFF_T_MAX
 376 # define OFF_T_MAX TYPE_MAXIMUM (off_t)
 377 #endif
 378
 379 #ifndef UID_T_MAX
 380 # define UID_T_MAX TYPE_MAXIMUM (uid_t)
 381 #endif
 382
 383 #ifndef GID_T_MAX
 384 # define GID_T_MAX TYPE_MAXIMUM (gid_t)
 385 #endif
 386
 387 #ifndef PID_T_MAX
 388 # define PID_T_MAX TYPE_MAXIMUM (pid_t)
 389 #endif
 390
 391 /* Use this to suppress gcc's `...may be used before initialized' warnings. */
 392 #ifdef lint
 393 # define IF_LINT(Code) Code
 394 #else
 395 # define IF_LINT(Code) /* empty */
 396 #endif
 397
 398 #ifndef __attribute__
 399 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
 400 #  define __attribute__(x) /* empty */
 401 # endif
 402 #endif
 403
 404 #ifndef ATTRIBUTE_NORETURN
 405 # define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
 406 #endif
 407
 408 #ifndef ATTRIBUTE_UNUSED
 409 # define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
 410 #endif
 411
 412 /* The warn_unused_result attribute appeared first in gcc-3.4.0 */
 413 #undef ATTRIBUTE_WARN_UNUSED_RESULT
 414 #if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
 415 # define ATTRIBUTE_WARN_UNUSED_RESULT /* empty */
 416 #else
 417 # define ATTRIBUTE_WARN_UNUSED_RESULT __attribute__ ((__warn_unused_result__))
 418 #endif
 419
 420 #if defined strdupa
 421 # define ASSIGN_STRDUPA(DEST, S)                \
 422   do { DEST = strdupa (S); } while (0)
 423 #else
 424 # define ASSIGN_STRDUPA(DEST, S)                \
 425   do                                            \
 426     {                                           \
 427       const char *s_ = (S);                     \
 428       size_t len_ = strlen (s_) + 1;            \
 429       char *tmp_dest_ = alloca (len_);          \
 430       DEST = memcpy (tmp_dest_, s_, len_);      \
 431     }                                           \
 432   while (0)
 433 #endif
 434
 435 #if ! HAVE_SYNC
 436 # define sync() /* empty */
 437 #endif
 438
 439 /* Compute the greatest common divisor of U and V using Euclid's
 440    algorithm.  U and V must be nonzero.  */
 441
 442 static inline size_t
 443 gcd (size_t u, size_t v)
 444 {
 445   do
 446     {
 447       size_t t = u % v;
 448       u = v;
 449       v = t;
 450     }
 451   while (v);
 452
 453   return u;
 454 }
 455
 456 /* Compute the least common multiple of U and V.  U and V must be
 457    nonzero.  There is no overflow checking, so callers should not
 458    specify outlandish sizes.  */
 459
 460 static inline size_t
 461 lcm (size_t u, size_t v)
 462 {
 463   return u * (v / gcd (u, v));
 464 }
 465
 466 /* Return PTR, aligned upward to the next multiple of ALIGNMENT.
 467    ALIGNMENT must be nonzero.  The caller must arrange for ((char *)
 468    PTR) through ((char *) PTR + ALIGNMENT - 1) to be addressable
 469    locations.  */
 470
 471 static inline void *
 472 ptr_align (void const *ptr, size_t alignment)
 473 {
 474   char const *p0 = ptr;
 475   char const *p1 = p0 + alignment - 1;
 476   return (void *) (p1 - (size_t) p1 % alignment);
 477 }
 478
 479 /* If 10*Accum + Digit_val is larger than the maximum value for Type,
 480    then don't update Accum and return false to indicate it would
 481    overflow.  Otherwise, set Accum to that new value and return true.
 482    Verify at compile-time that Type is Accum's type, and that Type is
 483    unsigned.  Accum must be an object, so that we can take its
 484    address.  Accum and Digit_val may be evaluated multiple times.
 485
 486    The "Added check" below is not strictly required, but it causes GCC
 487    to return a nonzero exit status instead of merely a warning
 488    diagnostic, and that is more useful.  */
 489
 490 #define DECIMAL_DIGIT_ACCUMULATE(Accum, Digit_val, Type)                \
 491   (                                                                     \
 492    (void) (&(Accum) == (Type *) NULL),  /* The type matches.  */        \
 493    (void) verify_true (! TYPE_SIGNED (Type)), /* The type is unsigned.  */ \
 494    (void) verify_true (sizeof (Accum) == sizeof (Type)), /* Added check.  */ \
 495    (((Type) -1 / 10 < (Accum)                                           \
 496      || (Type) ((Accum) * 10 + (Digit_val)) < (Accum))                  \
 497     ? false : (((Accum) = (Accum) * 10 + (Digit_val)), true))           \
 498   )
 499
 500 static inline void
 501 emit_size_note (void)
 502 {
 503   fputs (_("\n\
 504 SIZE may be (or may be an integer optionally followed by) one of following:\n\
 505 KB 1000, K 1024, MB 1000*1000, M 1024*1024, and so on for G, T, P, E, Z, Y.\n\
 506 "), stdout);
 507 }
 508
 509 static inline void
 510 emit_blocksize_note (char const *program)
 511 {
 512   printf (_("\n\
 513 Display values are in units of the first available SIZE from --block-size,\n\
 514 and the %s_BLOCK_SIZE, BLOCK_SIZE and BLOCKSIZE environment variables.\n\
 515 Otherwise, units default to 1024 bytes (or 512 if POSIXLY_CORRECT is set).\n\
 516 "), program);
 517 }
 518
 519 static inline void
 520 emit_ancillary_info (void)
 521 {
 522   printf (_("\nReport %s bugs to %s\n"), last_component (program_name),
 523           PACKAGE_BUGREPORT);
 524   printf (_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
 525   fputs (_("General help using GNU software: <http://www.gnu.org/gethelp/>\n"),
 526          stdout);
 527   /* Don't output this redundant message for English locales.
 528      Note we still output for 'C' so that it gets included in the man page.  */
 529   const char *lc_messages = setlocale (LC_MESSAGES, NULL);
 530   if (lc_messages && STRNCMP_LIT (lc_messages, "en_"))
 531     {
 532       /* TRANSLATORS: Replace LANG_CODE in this URL with your language code
 533          <http://translationproject.org/team/LANG_CODE.html> to form one of
 534          the URLs at http://translationproject.org/team/.  Otherwise, replace
 535          the entire URL with your translation team's email address.  */
 536       printf (_("Report %s translation bugs to "
 537                 "<http://translationproject.org/team/>\n"),
 538                 last_component (program_name));
 539     }
 540   printf (_("For complete documentation, run: "
 541             "info coreutils '%s invocation'\n"), last_component (program_name));
 542 }
 543
 544 #include "inttostr.h"
 545
 546 static inline char *
 547 timetostr (time_t t, char *buf)
 548 {
 549   return (TYPE_SIGNED (time_t)
 550           ? imaxtostr (t, buf)
 551           : umaxtostr (t, buf));
 552 }
 553
 554 static inline char *
 555 bad_cast (char const *s)
 556 {
 557   return (char *) s;
 558 }
 559
 560 void usage (int status) ATTRIBUTE_NORETURN;
 561
 562 #define emit_cycle_warning(file_name)   \
 563   do                                    \
 564     {                                   \
 565       error (0, 0, _("\
 566 WARNING: Circular directory structure.\n\
 567 This almost certainly means that you have a corrupted file system.\n\
 568 NOTIFY YOUR SYSTEM MANAGER.\n\
 569 The following directory is part of the cycle:\n  %s\n"), \
 570              quote (file_name));        \
 571     }                                   \
 572   while (0)
 573
 574 #ifndef ARRAY_CARDINALITY
 575 # define ARRAY_CARDINALITY(Array) (sizeof (Array) / sizeof *(Array))
 576 #endif