src/printf.c

   1 /* printf - format and print data
   2    Copyright (C) 1990-2010 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 /* Usage: printf format [argument...]
  18
  19    A front end to the printf function that lets it be used from the shell.
  20
  21    Backslash escapes:
  22
  23    \" = double quote
  24    \\ = backslash
  25    \a = alert (bell)
  26    \b = backspace
  27    \c = produce no further output
  28    \e = escape
  29    \f = form feed
  30    \n = new line
  31    \r = carriage return
  32    \t = horizontal tab
  33    \v = vertical tab
  34    \ooo = octal number (ooo is 1 to 3 digits)
  35    \xhh = hexadecimal number (hhh is 1 to 2 digits)
  36    \uhhhh = 16-bit Unicode character (hhhh is 4 digits)
  37    \Uhhhhhhhh = 32-bit Unicode character (hhhhhhhh is 8 digits)
  38
  39    Additional directive:
  40
  41    %b = print an argument string, interpreting backslash escapes,
  42      except that octal escapes are of the form \0 or \0ooo.
  43
  44    The `format' argument is re-used as many times as necessary
  45    to convert all of the given arguments.
  46
  47    David MacKenzie <djm@gnu.ai.mit.edu> */
  48
  49 #include <config.h>
  50 #include <stdio.h>
  51 #include <sys/types.h>
  52
  53 #include "system.h"
  54 #include "c-strtod.h"
  55 #include "error.h"
  56 #include "quote.h"
  57 #include "unicodeio.h"
  58 #include "xprintf.h"
  59
  60 /* The official name of this program (e.g., no `g' prefix).  */
  61 #define PROGRAM_NAME "printf"
  62
  63 #define AUTHORS proper_name ("David MacKenzie")
  64
  65 #define isodigit(c) ((c) >= '0' && (c) <= '7')
  66 #define hextobin(c) ((c) >= 'a' && (c) <= 'f' ? (c) - 'a' + 10 : \
  67                      (c) >= 'A' && (c) <= 'F' ? (c) - 'A' + 10 : (c) - '0')
  68 #define octtobin(c) ((c) - '0')
  69
  70 /* The value to return to the calling program.  */
  71 static int exit_status;
  72
  73 /* True if the POSIXLY_CORRECT environment variable is set.  */
  74 static bool posixly_correct;
  75
  76 /* This message appears in N_() here rather than just in _() below because
  77    the sole use would have been in a #define.  */
  78 static char const *const cfcc_msg =
  79  N_("warning: %s: character(s) following character constant have been ignored");
  80
  81 void
  82 usage (int status)
  83 {
  84   if (status != EXIT_SUCCESS)
  85     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  86              program_name);
  87   else
  88     {
  89       printf (_("\
  90 Usage: %s FORMAT [ARGUMENT]...\n\
  91   or:  %s OPTION\n\
  92 "),
  93               program_name, program_name);
  94       fputs (_("\
  95 Print ARGUMENT(s) according to FORMAT, or execute according to OPTION:\n\
  96 \n\
  97 "), stdout);
  98       fputs (HELP_OPTION_DESCRIPTION, stdout);
  99       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 100       fputs (_("\
 101 \n\
 102 FORMAT controls the output as in C printf.  Interpreted sequences are:\n\
 103 \n\
 104   \\\"      double quote\n\
 105 "), stdout);
 106       fputs (_("\
 107   \\\\      backslash\n\
 108   \\a      alert (BEL)\n\
 109   \\b      backspace\n\
 110   \\c      produce no further output\n\
 111   \\e      escape\n\
 112   \\f      form feed\n\
 113   \\n      new line\n\
 114   \\r      carriage return\n\
 115   \\t      horizontal tab\n\
 116   \\v      vertical tab\n\
 117 "), stdout);
 118       fputs (_("\
 119   \\NNN    byte with octal value NNN (1 to 3 digits)\n\
 120   \\xHH    byte with hexadecimal value HH (1 to 2 digits)\n\
 121   \\uHHHH  Unicode (ISO/IEC 10646) character with hex value HHHH (4 digits)\n\
 122   \\UHHHHHHHH  Unicode character with hex value HHHHHHHH (8 digits)\n\
 123 "), stdout);
 124       fputs (_("\
 125   %%      a single %\n\
 126   %b      ARGUMENT as a string with `\\' escapes interpreted,\n\
 127           except that octal escapes are of the form \\0 or \\0NNN\n\
 128 \n\
 129 and all C format specifications ending with one of diouxXfeEgGcs, with\n\
 130 ARGUMENTs converted to proper type first.  Variable widths are handled.\n\
 131 "), stdout);
 132       printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
 133       emit_ancillary_info ();
 134     }
 135   exit (status);
 136 }
 137
 138 static void
 139 verify_numeric (const char *s, const char *end)
 140 {
 141   if (errno)
 142     {
 143       error (0, errno, "%s", s);
 144       exit_status = EXIT_FAILURE;
 145     }
 146   else if (*end)
 147     {
 148       if (s == end)
 149         error (0, 0, _("%s: expected a numeric value"), s);
 150       else
 151         error (0, 0, _("%s: value not completely converted"), s);
 152       exit_status = EXIT_FAILURE;
 153     }
 154 }
 155
 156 #define STRTOX(TYPE, FUNC_NAME, LIB_FUNC_EXPR)                           \
 157 static TYPE                                                              \
 158 FUNC_NAME (char const *s)                                                \
 159 {                                                                        \
 160   char *end;                                                             \
 161   TYPE val;                                                              \
 162                                                                          \
 163   if (*s == '\"' || *s == '\'')                                          \
 164     {                                                                    \
 165       unsigned char ch = *++s;                                           \
 166       val = ch;                                                          \
 167       /* If POSIXLY_CORRECT is not set, then give a warning that there   \
 168          are characters following the character constant and that GNU    \
 169          printf is ignoring those characters.  If POSIXLY_CORRECT *is*   \
 170          set, then don't give the warning.  */                           \
 171       if (*++s != 0 && !posixly_correct)                                 \
 172         error (0, 0, _(cfcc_msg), s);                                    \
 173     }                                                                    \
 174   else                                                                   \
 175     {                                                                    \
 176       errno = 0;                                                         \
 177       val = (LIB_FUNC_EXPR);                                             \
 178       verify_numeric (s, end);                                           \
 179     }                                                                    \
 180   return val;                                                            \
 181 }                                                                        \
 182
 183 STRTOX (intmax_t,    vstrtoimax, strtoimax (s, &end, 0))
 184 STRTOX (uintmax_t,   vstrtoumax, strtoumax (s, &end, 0))
 185 STRTOX (long double, vstrtold,   c_strtold (s, &end))
 186
 187 /* Output a single-character \ escape.  */
 188
 189 static void
 190 print_esc_char (char c)
 191 {
 192   switch (c)
 193     {
 194     case 'a':                   /* Alert. */
 195       putchar ('\a');
 196       break;
 197     case 'b':                   /* Backspace. */
 198       putchar ('\b');
 199       break;
 200     case 'c':                   /* Cancel the rest of the output. */
 201       exit (EXIT_SUCCESS);
 202       break;
 203     case 'e':                   /* Escape. */
 204       putchar ('\x1B');
 205       break;
 206     case 'f':                   /* Form feed. */
 207       putchar ('\f');
 208       break;
 209     case 'n':                   /* New line. */
 210       putchar ('\n');
 211       break;
 212     case 'r':                   /* Carriage return. */
 213       putchar ('\r');
 214       break;
 215     case 't':                   /* Horizontal tab. */
 216       putchar ('\t');
 217       break;
 218     case 'v':                   /* Vertical tab. */
 219       putchar ('\v');
 220       break;
 221     default:
 222       putchar (c);
 223       break;
 224     }
 225 }
 226
 227 /* Print a \ escape sequence starting at ESCSTART.
 228    Return the number of characters in the escape sequence
 229    besides the backslash.
 230    If OCTAL_0 is nonzero, octal escapes are of the form \0ooo, where o
 231    is an octal digit; otherwise they are of the form \ooo.  */
 232
 233 static int
 234 print_esc (const char *escstart, bool octal_0)
 235 {
 236   const char *p = escstart + 1;
 237   int esc_value = 0;            /* Value of \nnn escape. */
 238   int esc_length;               /* Length of \nnn escape. */
 239
 240   if (*p == 'x')
 241     {
 242       /* A hexadecimal \xhh escape sequence must have 1 or 2 hex. digits.  */
 243       for (esc_length = 0, ++p;
 244            esc_length < 2 && isxdigit (to_uchar (*p));
 245            ++esc_length, ++p)
 246         esc_value = esc_value * 16 + hextobin (*p);
 247       if (esc_length == 0)
 248         error (EXIT_FAILURE, 0, _("missing hexadecimal number in escape"));
 249       putchar (esc_value);
 250     }
 251   else if (isodigit (*p))
 252     {
 253       /* Parse \0ooo (if octal_0 && *p == '0') or \ooo (otherwise).
 254          Allow \ooo if octal_0 && *p != '0'; this is an undocumented
 255          extension to POSIX that is compatible with Bash 2.05b.  */
 256       for (esc_length = 0, p += octal_0 && *p == '0';
 257            esc_length < 3 && isodigit (*p);
 258            ++esc_length, ++p)
 259         esc_value = esc_value * 8 + octtobin (*p);
 260       putchar (esc_value);
 261     }
 262   else if (*p && strchr ("\"\\abcefnrtv", *p))
 263     print_esc_char (*p++);
 264   else if (*p == 'u' || *p == 'U')
 265     {
 266       char esc_char = *p;
 267       unsigned int uni_value;
 268
 269       uni_value = 0;
 270       for (esc_length = (esc_char == 'u' ? 4 : 8), ++p;
 271            esc_length > 0;
 272            --esc_length, ++p)
 273         {
 274           if (! isxdigit (to_uchar (*p)))
 275             error (EXIT_FAILURE, 0, _("missing hexadecimal number in escape"));
 276           uni_value = uni_value * 16 + hextobin (*p);
 277         }
 278
 279       /* A universal character name shall not specify a character short
 280          identifier in the range 00000000 through 00000020, 0000007F through
 281          0000009F, or 0000D800 through 0000DFFF inclusive. A universal
 282          character name shall not designate a character in the required
 283          character set.  */
 284       if ((uni_value <= 0x9f
 285            && uni_value != 0x24 && uni_value != 0x40 && uni_value != 0x60)
 286           || (uni_value >= 0xd800 && uni_value <= 0xdfff))
 287         error (EXIT_FAILURE, 0, _("invalid universal character name \\%c%0*x"),
 288                esc_char, (esc_char == 'u' ? 4 : 8), uni_value);
 289
 290       print_unicode_char (stdout, uni_value, 0);
 291     }
 292   else
 293     {
 294       putchar ('\\');
 295       if (*p)
 296         {
 297           putchar (*p);
 298           p++;
 299         }
 300     }
 301   return p - escstart - 1;
 302 }
 303
 304 /* Print string STR, evaluating \ escapes. */
 305
 306 static void
 307 print_esc_string (const char *str)
 308 {
 309   for (; *str; str++)
 310     if (*str == '\\')
 311       str += print_esc (str, true);
 312     else
 313       putchar (*str);
 314 }
 315
 316 /* Evaluate a printf conversion specification.  START is the start of
 317    the directive, LENGTH is its length, and CONVERSION specifies the
 318    type of conversion.  LENGTH does not include any length modifier or
 319    the conversion specifier itself.  FIELD_WIDTH and PRECISION are the
 320    field width and precision for '*' values, if HAVE_FIELD_WIDTH and
 321    HAVE_PRECISION are true, respectively.  ARGUMENT is the argument to
 322    be formatted.  */
 323
 324 static void
 325 print_direc (const char *start, size_t length, char conversion,
 326              bool have_field_width, int field_width,
 327              bool have_precision, int precision,
 328              char const *argument)
 329 {
 330   char *p;              /* Null-terminated copy of % directive. */
 331
 332   /* Create a null-terminated copy of the % directive, with an
 333      intmax_t-wide length modifier substituted for any existing
 334      integer length modifier.  */
 335   {
 336     char *q;
 337     char const *length_modifier;
 338     size_t length_modifier_len;
 339
 340     switch (conversion)
 341       {
 342       case 'd': case 'i': case 'o': case 'u': case 'x': case 'X':
 343         length_modifier = PRIdMAX;
 344         length_modifier_len = sizeof PRIdMAX - 2;
 345         break;
 346
 347       case 'a': case 'e': case 'f': case 'g':
 348       case 'A': case 'E': case 'F': case 'G':
 349         length_modifier = "L";
 350         length_modifier_len = 1;
 351         break;
 352
 353       default:
 354         length_modifier = start;  /* Any valid pointer will do.  */
 355         length_modifier_len = 0;
 356         break;
 357       }
 358
 359     p = xmalloc (length + length_modifier_len + 2);
 360     q = mempcpy (p, start, length);
 361     q = mempcpy (q, length_modifier, length_modifier_len);
 362     *q++ = conversion;
 363     *q = '\0';
 364   }
 365
 366   switch (conversion)
 367     {
 368     case 'd':
 369     case 'i':
 370       {
 371         intmax_t arg = vstrtoimax (argument);
 372         if (!have_field_width)
 373           {
 374             if (!have_precision)
 375               xprintf (p, arg);
 376             else
 377               xprintf (p, precision, arg);
 378           }
 379         else
 380           {
 381             if (!have_precision)
 382               xprintf (p, field_width, arg);
 383             else
 384               xprintf (p, field_width, precision, arg);
 385           }
 386       }
 387       break;
 388
 389     case 'o':
 390     case 'u':
 391     case 'x':
 392     case 'X':
 393       {
 394         uintmax_t arg = vstrtoumax (argument);
 395         if (!have_field_width)
 396           {
 397             if (!have_precision)
 398               xprintf (p, arg);
 399             else
 400               xprintf (p, precision, arg);
 401           }
 402         else
 403           {
 404             if (!have_precision)
 405               xprintf (p, field_width, arg);
 406             else
 407               xprintf (p, field_width, precision, arg);
 408           }
 409       }
 410       break;
 411
 412     case 'a':
 413     case 'A':
 414     case 'e':
 415     case 'E':
 416     case 'f':
 417     case 'F':
 418     case 'g':
 419     case 'G':
 420       {
 421         long double arg = vstrtold (argument);
 422         if (!have_field_width)
 423           {
 424             if (!have_precision)
 425               xprintf (p, arg);
 426             else
 427               xprintf (p, precision, arg);
 428           }
 429         else
 430           {
 431             if (!have_precision)
 432               xprintf (p, field_width, arg);
 433             else
 434               xprintf (p, field_width, precision, arg);
 435           }
 436       }
 437       break;
 438
 439     case 'c':
 440       if (!have_field_width)
 441         xprintf (p, *argument);
 442       else
 443         xprintf (p, field_width, *argument);
 444       break;
 445
 446     case 's':
 447       if (!have_field_width)
 448         {
 449           if (!have_precision)
 450             xprintf (p, argument);
 451           else
 452             xprintf (p, precision, argument);
 453         }
 454       else
 455         {
 456           if (!have_precision)
 457             xprintf (p, field_width, argument);
 458           else
 459             xprintf (p, field_width, precision, argument);
 460         }
 461       break;
 462     }
 463
 464   free (p);
 465 }
 466
 467 /* Print the text in FORMAT, using ARGV (with ARGC elements) for
 468    arguments to any `%' directives.
 469    Return the number of elements of ARGV used.  */
 470
 471 static int
 472 print_formatted (const char *format, int argc, char **argv)
 473 {
 474   int save_argc = argc;         /* Preserve original value.  */
 475   const char *f;                /* Pointer into `format'.  */
 476   const char *direc_start;      /* Start of % directive.  */
 477   size_t direc_length;          /* Length of % directive.  */
 478   bool have_field_width;        /* True if FIELD_WIDTH is valid.  */
 479   int field_width = 0;          /* Arg to first '*'.  */
 480   bool have_precision;          /* True if PRECISION is valid.  */
 481   int precision = 0;            /* Arg to second '*'.  */
 482   char ok[UCHAR_MAX + 1];       /* ok['x'] is true if %x is allowed.  */
 483
 484   for (f = format; *f; ++f)
 485     {
 486       switch (*f)
 487         {
 488         case '%':
 489           direc_start = f++;
 490           direc_length = 1;
 491           have_field_width = have_precision = false;
 492           if (*f == '%')
 493             {
 494               putchar ('%');
 495               break;
 496             }
 497           if (*f == 'b')
 498             {
 499               /* FIXME: Field width and precision are not supported
 500                  for %b, even though POSIX requires it.  */
 501               if (argc > 0)
 502                 {
 503                   print_esc_string (*argv);
 504                   ++argv;
 505                   --argc;
 506                 }
 507               break;
 508             }
 509
 510           memset (ok, 0, sizeof ok);
 511           ok['a'] = ok['A'] = ok['c'] = ok['d'] = ok['e'] = ok['E'] =
 512             ok['f'] = ok['F'] = ok['g'] = ok['G'] = ok['i'] = ok['o'] =
 513             ok['s'] = ok['u'] = ok['x'] = ok['X'] = 1;
 514
 515           for (;; f++, direc_length++)
 516             switch (*f)
 517               {
 518 #if (__GLIBC__ == 2 && 2 <= __GLIBC_MINOR__) || 3 <= __GLIBC__
 519               case 'I':
 520 #endif
 521               case '\'':
 522                 ok['a'] = ok['A'] = ok['c'] = ok['e'] = ok['E'] =
 523                   ok['o'] = ok['s'] = ok['x'] = ok['X'] = 0;
 524                 break;
 525               case '-': case '+': case ' ':
 526                 break;
 527               case '#':
 528                 ok['c'] = ok['d'] = ok['i'] = ok['s'] = ok['u'] = 0;
 529                 break;
 530               case '0':
 531                 ok['c'] = ok['s'] = 0;
 532                 break;
 533               default:
 534                 goto no_more_flag_characters;
 535               }
 536         no_more_flag_characters:;
 537
 538           if (*f == '*')
 539             {
 540               ++f;
 541               ++direc_length;
 542               if (argc > 0)
 543                 {
 544                   intmax_t width = vstrtoimax (*argv);
 545                   if (INT_MIN <= width && width <= INT_MAX)
 546                     field_width = width;
 547                   else
 548                     error (EXIT_FAILURE, 0, _("invalid field width: %s"),
 549                            *argv);
 550                   ++argv;
 551                   --argc;
 552                 }
 553               else
 554                 field_width = 0;
 555               have_field_width = true;
 556             }
 557           else
 558             while (ISDIGIT (*f))
 559               {
 560                 ++f;
 561                 ++direc_length;
 562               }
 563           if (*f == '.')
 564             {
 565               ++f;
 566               ++direc_length;
 567               ok['c'] = 0;
 568               if (*f == '*')
 569                 {
 570                   ++f;
 571                   ++direc_length;
 572                   if (argc > 0)
 573                     {
 574                       intmax_t prec = vstrtoimax (*argv);
 575                       if (prec < 0)
 576                         {
 577                           /* A negative precision is taken as if the
 578                              precision were omitted, so -1 is safe
 579                              here even if prec < INT_MIN.  */
 580                           precision = -1;
 581                         }
 582                       else if (INT_MAX < prec)
 583                         error (EXIT_FAILURE, 0, _("invalid precision: %s"),
 584                                *argv);
 585                       else
 586                         precision = prec;
 587                       ++argv;
 588                       --argc;
 589                     }
 590                   else
 591                     precision = 0;
 592                   have_precision = true;
 593                 }
 594               else
 595                 while (ISDIGIT (*f))
 596                   {
 597                     ++f;
 598                     ++direc_length;
 599                   }
 600             }
 601
 602           while (*f == 'l' || *f == 'L' || *f == 'h'
 603                  || *f == 'j' || *f == 't' || *f == 'z')
 604             ++f;
 605
 606           {
 607             unsigned char conversion = *f;
 608             if (! ok[conversion])
 609               error (EXIT_FAILURE, 0,
 610                      _("%.*s: invalid conversion specification"),
 611                      (int) (f + 1 - direc_start), direc_start);
 612           }
 613
 614           print_direc (direc_start, direc_length, *f,
 615                        have_field_width, field_width,
 616                        have_precision, precision,
 617                        (argc <= 0 ? "" : (argc--, *argv++)));
 618           break;
 619
 620         case '\\':
 621           f += print_esc (f, false);
 622           break;
 623
 624         default:
 625           putchar (*f);
 626         }
 627     }
 628
 629   return save_argc - argc;
 630 }
 631
 632 int
 633 main (int argc, char **argv)
 634 {
 635   char *format;
 636   int args_used;
 637
 638   initialize_main (&argc, &argv);
 639   set_program_name (argv[0]);
 640   setlocale (LC_ALL, "");
 641   bindtextdomain (PACKAGE, LOCALEDIR);
 642   textdomain (PACKAGE);
 643
 644   atexit (close_stdout);
 645
 646   exit_status = EXIT_SUCCESS;
 647
 648   posixly_correct = (getenv ("POSIXLY_CORRECT") != NULL);
 649
 650   /* We directly parse options, rather than use parse_long_options, in
 651      order to avoid accepting abbreviations.  */
 652   if (argc == 2)
 653     {
 654       if (STREQ (argv[1], "--help"))
 655         usage (EXIT_SUCCESS);
 656
 657       if (STREQ (argv[1], "--version"))
 658         {
 659           version_etc (stdout, PROGRAM_NAME, PACKAGE_NAME, Version, AUTHORS,
 660                        (char *) NULL);
 661           exit (EXIT_SUCCESS);
 662         }
 663     }
 664
 665   /* The above handles --help and --version.
 666      Since there is no other invocation of getopt, handle `--' here.  */
 667   if (1 < argc && STREQ (argv[1], "--"))
 668     {
 669       --argc;
 670       ++argv;
 671     }
 672
 673   if (argc <= 1)
 674     {
 675       error (0, 0, _("missing operand"));
 676       usage (EXIT_FAILURE);
 677     }
 678
 679   format = argv[1];
 680   argc -= 2;
 681   argv += 2;
 682
 683   do
 684     {
 685       args_used = print_formatted (format, argc, argv);
 686       argc -= args_used;
 687       argv += args_used;
 688     }
 689   while (args_used > 0 && argc > 0);
 690
 691   if (argc > 0)
 692     error (0, 0,
 693            _("warning: ignoring excess arguments, starting with %s"),
 694            quote (argv[0]));
 695
 696   exit (exit_status);
 697 }