summaryrefslogtreecommitdiff
path: root/src/cat.c
blob: f337c34e697540011dc796f8731612be2294292d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
/* cat -- concatenate files and print on the standard output.
   Copyright (C) 1988-2016 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Differences from the Unix cat:
   * Always unbuffered, -u is ignored.
   * Usually much faster than other versions of cat, the difference
   is especially apparent when using the -v option.

   By tege@sics.se, Torbjorn Granlund, advised by rms, Richard Stallman.  */

#include <config.h>

#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>

#if HAVE_STROPTS_H
# include <stropts.h>
#endif
#include <sys/ioctl.h>

#include "system.h"
#include "ioblksize.h"
#include "die.h"
#include "error.h"
#include "fadvise.h"
#include "full-write.h"
#include "safe-read.h"
#include "xfreopen.h"

/* The official name of this program (e.g., no 'g' prefix).  */
#define PROGRAM_NAME "cat"

#define AUTHORS \
  proper_name ("Torbjorn Granlund"), \
  proper_name ("Richard M. Stallman")

/* Name of input file.  May be "-".  */
static char const *infile;

/* Descriptor on which input file is open.  */
static int input_desc;

/* Buffer for line numbers.
   An 11 digit counter may overflow within an hour on a P2/466,
   an 18 digit counter needs about 1000y */
#define LINE_COUNTER_BUF_LEN 20
static char line_buf[LINE_COUNTER_BUF_LEN] =
  {
    ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
    ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', '0',
    '\t', '\0'
  };

/* Position in 'line_buf' where printing starts.  This will not change
   unless the number of lines is larger than 999999.  */
static char *line_num_print = line_buf + LINE_COUNTER_BUF_LEN - 8;

/* Position of the first digit in 'line_buf'.  */
static char *line_num_start = line_buf + LINE_COUNTER_BUF_LEN - 3;

/* Position of the last digit in 'line_buf'.  */
static char *line_num_end = line_buf + LINE_COUNTER_BUF_LEN - 3;

/* Preserves the 'cat' function's local 'newlines' between invocations.  */
static int newlines2 = 0;

void
usage (int status)
{
  if (status != EXIT_SUCCESS)
    emit_try_help ();
  else
    {
      printf (_("\
Usage: %s [OPTION]... [FILE]...\n\
"),
              program_name);
      fputs (_("\
Concatenate FILE(s) to standard output.\n\
"), stdout);

      emit_stdin_note ();

      fputs (_("\
\n\
  -A, --show-all           equivalent to -vET\n\
  -b, --number-nonblank    number nonempty output lines, overrides -n\n\
  -e                       equivalent to -vE\n\
  -E, --show-ends          display $ at end of each line\n\
  -n, --number             number all output lines\n\
  -s, --squeeze-blank      suppress repeated empty output lines\n\
"), stdout);
      fputs (_("\
  -t                       equivalent to -vT\n\
  -T, --show-tabs          display TAB characters as ^I\n\
  -u                       (ignored)\n\
  -v, --show-nonprinting   use ^ and M- notation, except for LFD and TAB\n\
"), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      printf (_("\
\n\
Examples:\n\
  %s f - g  Output f's contents, then standard input, then g's contents.\n\
  %s        Copy standard input to standard output.\n\
"),
              program_name, program_name);
      emit_ancillary_info (PROGRAM_NAME);
    }
  exit (status);
}

/* Compute the next line number.  */

static void
next_line_num (void)
{
  char *endp = line_num_end;
  do
    {
      if ((*endp)++ < '9')
        return;
      *endp-- = '0';
    }
  while (endp >= line_num_start);
  if (line_num_start > line_buf)
    *--line_num_start = '1';
  else
    *line_buf = '>';
  if (line_num_start < line_num_print)
    line_num_print--;
}

/* Plain cat.  Copies the file behind 'input_desc' to STDOUT_FILENO.
   Return true if successful.  */

static bool
simple_cat (
     /* Pointer to the buffer, used by reads and writes.  */
     char *buf,

     /* Number of characters preferably read or written by each read and write
        call.  */
     size_t bufsize)
{
  /* Actual number of characters read, and therefore written.  */
  size_t n_read;

  /* Loop until the end of the file.  */

  while (true)
    {
      /* Read a block of input.  */

      n_read = safe_read (input_desc, buf, bufsize);
      if (n_read == SAFE_READ_ERROR)
        {
          error (0, errno, "%s", quotef (infile));
          return false;
        }

      /* End of this file?  */

      if (n_read == 0)
        return true;

      /* Write this block out.  */

      {
        /* The following is ok, since we know that 0 < n_read.  */
        size_t n = n_read;
        if (full_write (STDOUT_FILENO, buf, n) != n)
          die (EXIT_FAILURE, errno, _("write error"));
      }
    }
}

/* Write any pending output to STDOUT_FILENO.
   Pending is defined to be the *BPOUT - OUTBUF bytes starting at OUTBUF.
   Then set *BPOUT to OUTPUT if it's not already that value.  */

static inline void
write_pending (char *outbuf, char **bpout)
{
  size_t n_write = *bpout - outbuf;
  if (0 < n_write)
    {
      if (full_write (STDOUT_FILENO, outbuf, n_write) != n_write)
        die (EXIT_FAILURE, errno, _("write error"));
      *bpout = outbuf;
    }
}

/* Cat the file behind INPUT_DESC to the file behind OUTPUT_DESC.
   Return true if successful.
   Called if any option more than -u was specified.

   A newline character is always put at the end of the buffer, to make
   an explicit test for buffer end unnecessary.  */

static bool
cat (
     /* Pointer to the beginning of the input buffer.  */
     char *inbuf,

     /* Number of characters read in each read call.  */
     size_t insize,

     /* Pointer to the beginning of the output buffer.  */
     char *outbuf,

     /* Number of characters written by each write call.  */
     size_t outsize,

     /* Variables that have values according to the specified options.  */
     bool show_nonprinting,
     bool show_tabs,
     bool number,
     bool number_nonblank,
     bool show_ends,
     bool squeeze_blank)
{
  /* Last character read from the input buffer.  */
  unsigned char ch;

  /* Pointer to the next character in the input buffer.  */
  char *bpin;

  /* Pointer to the first non-valid byte in the input buffer, i.e., the
     current end of the buffer.  */
  char *eob;

  /* Pointer to the position where the next character shall be written.  */
  char *bpout;

  /* Number of characters read by the last read call.  */
  size_t n_read;

  /* Determines how many consecutive newlines there have been in the
     input.  0 newlines makes NEWLINES -1, 1 newline makes NEWLINES 1,
     etc.  Initially 0 to indicate that we are at the beginning of a
     new line.  The "state" of the procedure is determined by
     NEWLINES.  */
  int newlines = newlines2;

#ifdef FIONREAD
  /* If nonzero, use the FIONREAD ioctl, as an optimization.
     (On Ultrix, it is not supported on NFS file systems.)  */
  bool use_fionread = true;
#endif

  /* The inbuf pointers are initialized so that BPIN > EOB, and thereby input
     is read immediately.  */

  eob = inbuf;
  bpin = eob + 1;

  bpout = outbuf;

  while (true)
    {
      do
        {
          /* Write if there are at least OUTSIZE bytes in OUTBUF.  */

          if (outbuf + outsize <= bpout)
            {
              char *wp = outbuf;
              size_t remaining_bytes;
              do
                {
                  if (full_write (STDOUT_FILENO, wp, outsize) != outsize)
                    die (EXIT_FAILURE, errno, _("write error"));
                  wp += outsize;
                  remaining_bytes = bpout - wp;
                }
              while (outsize <= remaining_bytes);

              /* Move the remaining bytes to the beginning of the
                 buffer.  */

              memmove (outbuf, wp, remaining_bytes);
              bpout = outbuf + remaining_bytes;
            }

          /* Is INBUF empty?  */

          if (bpin > eob)
            {
              bool input_pending = false;
#ifdef FIONREAD
              int n_to_read = 0;

              /* Is there any input to read immediately?
                 If not, we are about to wait,
                 so write all buffered output before waiting.  */

              if (use_fionread
                  && ioctl (input_desc, FIONREAD, &n_to_read) < 0)
                {
                  /* Ultrix returns EOPNOTSUPP on NFS;
                     HP-UX returns ENOTTY on pipes.
                     SunOS returns EINVAL and
                     More/BSD returns ENODEV on special files
                     like /dev/null.
                     Irix-5 returns ENOSYS on pipes.  */
                  if (errno == EOPNOTSUPP || errno == ENOTTY
                      || errno == EINVAL || errno == ENODEV
                      || errno == ENOSYS)
                    use_fionread = false;
                  else
                    {
                      error (0, errno, _("cannot do ioctl on %s"),
                             quoteaf (infile));
                      newlines2 = newlines;
                      return false;
                    }
                }
              if (n_to_read != 0)
                input_pending = true;
#endif

              if (!input_pending)
                write_pending (outbuf, &bpout);

              /* Read more input into INBUF.  */

              n_read = safe_read (input_desc, inbuf, insize);
              if (n_read == SAFE_READ_ERROR)
                {
                  error (0, errno, "%s", quotef (infile));
                  write_pending (outbuf, &bpout);
                  newlines2 = newlines;
                  return false;
                }
              if (n_read == 0)
                {
                  write_pending (outbuf, &bpout);
                  newlines2 = newlines;
                  return true;
                }

              /* Update the pointers and insert a sentinel at the buffer
                 end.  */

              bpin = inbuf;
              eob = bpin + n_read;
              *eob = '\n';
            }
          else
            {
              /* It was a real (not a sentinel) newline.  */

              /* Was the last line empty?
                 (i.e., have two or more consecutive newlines been read?)  */

              if (++newlines > 0)
                {
                  if (newlines >= 2)
                    {
                      /* Limit this to 2 here.  Otherwise, with lots of
                         consecutive newlines, the counter could wrap
                         around at INT_MAX.  */
                      newlines = 2;

                      /* Are multiple adjacent empty lines to be substituted
                         by single ditto (-s), and this was the second empty
                         line?  */
                      if (squeeze_blank)
                        {
                          ch = *bpin++;
                          continue;
                        }
                    }

                  /* Are line numbers to be written at empty lines (-n)?  */

                  if (number && !number_nonblank)
                    {
                      next_line_num ();
                      bpout = stpcpy (bpout, line_num_print);
                    }
                }

              /* Output a currency symbol if requested (-e).  */

              if (show_ends)
                *bpout++ = '$';

              /* Output the newline.  */

              *bpout++ = '\n';
            }
          ch = *bpin++;
        }
      while (ch == '\n');

      /* Are we at the beginning of a line, and line numbers are requested?  */

      if (newlines >= 0 && number)
        {
          next_line_num ();
          bpout = stpcpy (bpout, line_num_print);
        }

      /* Here CH cannot contain a newline character.  */

      /* The loops below continue until a newline character is found,
         which means that the buffer is empty or that a proper newline
         has been found.  */

      /* If quoting, i.e., at least one of -v, -e, or -t specified,
         scan for chars that need conversion.  */
      if (show_nonprinting)
        {
          while (true)
            {
              if (ch >= 32)
                {
                  if (ch < 127)
                    *bpout++ = ch;
                  else if (ch == 127)
                    {
                      *bpout++ = '^';
                      *bpout++ = '?';
                    }
                  else
                    {
                      *bpout++ = 'M';
                      *bpout++ = '-';
                      if (ch >= 128 + 32)
                        {
                          if (ch < 128 + 127)
                            *bpout++ = ch - 128;
                          else
                            {
                              *bpout++ = '^';
                              *bpout++ = '?';
                            }
                        }
                      else
                        {
                          *bpout++ = '^';
                          *bpout++ = ch - 128 + 64;
                        }
                    }
                }
              else if (ch == '\t' && !show_tabs)
                *bpout++ = '\t';
              else if (ch == '\n')
                {
                  newlines = -1;
                  break;
                }
              else
                {
                  *bpout++ = '^';
                  *bpout++ = ch + 64;
                }

              ch = *bpin++;
            }
        }
      else
        {
          /* Not quoting, neither of -v, -e, or -t specified.  */
          while (true)
            {
              if (ch == '\t' && show_tabs)
                {
                  *bpout++ = '^';
                  *bpout++ = ch + 64;
                }
              else if (ch != '\n')
                *bpout++ = ch;
              else
                {
                  newlines = -1;
                  break;
                }

              ch = *bpin++;
            }
        }
    }
}

int
main (int argc, char **argv)
{
  /* Optimal size of i/o operations of output.  */
  size_t outsize;

  /* Optimal size of i/o operations of input.  */
  size_t insize;

  size_t page_size = getpagesize ();

  /* Pointer to the input buffer.  */
  char *inbuf;

  /* Pointer to the output buffer.  */
  char *outbuf;

  bool ok = true;
  int c;

  /* Index in argv to processed argument.  */
  int argind;

  /* Device number of the output (file or whatever).  */
  dev_t out_dev;

  /* I-node number of the output.  */
  ino_t out_ino;

  /* True if the output is a regular file.  */
  bool out_isreg;

  /* Nonzero if we have ever read standard input.  */
  bool have_read_stdin = false;

  struct stat stat_buf;

  /* Variables that are set according to the specified options.  */
  bool number = false;
  bool number_nonblank = false;
  bool squeeze_blank = false;
  bool show_ends = false;
  bool show_nonprinting = false;
  bool show_tabs = false;
  int file_open_mode = O_RDONLY;

  static struct option const long_options[] =
  {
    {"number-nonblank", no_argument, NULL, 'b'},
    {"number", no_argument, NULL, 'n'},
    {"squeeze-blank", no_argument, NULL, 's'},
    {"show-nonprinting", no_argument, NULL, 'v'},
    {"show-ends", no_argument, NULL, 'E'},
    {"show-tabs", no_argument, NULL, 'T'},
    {"show-all", no_argument, NULL, 'A'},
    {GETOPT_HELP_OPTION_DECL},
    {GETOPT_VERSION_OPTION_DECL},
    {NULL, 0, NULL, 0}
  };

  initialize_main (&argc, &argv);
  set_program_name (argv[0]);
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  /* Arrange to close stdout if we exit via the
     case_GETOPT_HELP_CHAR or case_GETOPT_VERSION_CHAR code.
     Normally STDOUT_FILENO is used rather than stdout, so
     close_stdout does nothing.  */
  atexit (close_stdout);

  /* Parse command line options.  */

  while ((c = getopt_long (argc, argv, "benstuvAET", long_options, NULL))
         != -1)
    {
      switch (c)
        {
        case 'b':
          number = true;
          number_nonblank = true;
          break;

        case 'e':
          show_ends = true;
          show_nonprinting = true;
          break;

        case 'n':
          number = true;
          break;

        case 's':
          squeeze_blank = true;
          break;

        case 't':
          show_tabs = true;
          show_nonprinting = true;
          break;

        case 'u':
          /* We provide the -u feature unconditionally.  */
          break;

        case 'v':
          show_nonprinting = true;
          break;

        case 'A':
          show_nonprinting = true;
          show_ends = true;
          show_tabs = true;
          break;

        case 'E':
          show_ends = true;
          break;

        case 'T':
          show_tabs = true;
          break;

        case_GETOPT_HELP_CHAR;

        case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);

        default:
          usage (EXIT_FAILURE);
        }
    }

  /* Get device, i-node number, and optimal blocksize of output.  */

  if (fstat (STDOUT_FILENO, &stat_buf) < 0)
    die (EXIT_FAILURE, errno, _("standard output"));

  outsize = io_blksize (stat_buf);
  out_dev = stat_buf.st_dev;
  out_ino = stat_buf.st_ino;
  out_isreg = S_ISREG (stat_buf.st_mode) != 0;

  if (! (number || show_ends || squeeze_blank))
    {
      file_open_mode |= O_BINARY;
      if (O_BINARY && ! isatty (STDOUT_FILENO))
        xfreopen (NULL, "wb", stdout);
    }

  /* Check if any of the input files are the same as the output file.  */

  /* Main loop.  */

  infile = "-";
  argind = optind;

  do
    {
      if (argind < argc)
        infile = argv[argind];

      if (STREQ (infile, "-"))
        {
          have_read_stdin = true;
          input_desc = STDIN_FILENO;
          if ((file_open_mode & O_BINARY) && ! isatty (STDIN_FILENO))
            xfreopen (NULL, "rb", stdin);
        }
      else
        {
          input_desc = open (infile, file_open_mode);
          if (input_desc < 0)
            {
              error (0, errno, "%s", quotef (infile));
              ok = false;
              continue;
            }
        }

      if (fstat (input_desc, &stat_buf) < 0)
        {
          error (0, errno, "%s", quotef (infile));
          ok = false;
          goto contin;
        }
      insize = io_blksize (stat_buf);

      fdadvise (input_desc, 0, 0, FADVISE_SEQUENTIAL);

      /* Don't copy a nonempty regular file to itself, as that would
         merely exhaust the output device.  It's better to catch this
         error earlier rather than later.  */

      if (out_isreg
          && stat_buf.st_dev == out_dev && stat_buf.st_ino == out_ino
          && lseek (input_desc, 0, SEEK_CUR) < stat_buf.st_size)
        {
          error (0, 0, _("%s: input file is output file"), quotef (infile));
          ok = false;
          goto contin;
        }

      /* Select which version of 'cat' to use.  If any format-oriented
         options were given use 'cat'; otherwise use 'simple_cat'.  */

      if (! (number || show_ends || show_nonprinting
             || show_tabs || squeeze_blank))
        {
          insize = MAX (insize, outsize);
          inbuf = xmalloc (insize + page_size - 1);

          ok &= simple_cat (ptr_align (inbuf, page_size), insize);
        }
      else
        {
          inbuf = xmalloc (insize + 1 + page_size - 1);

          /* Why are
             (OUTSIZE - 1 + INSIZE * 4 + LINE_COUNTER_BUF_LEN + PAGE_SIZE - 1)
             bytes allocated for the output buffer?

             A test whether output needs to be written is done when the input
             buffer empties or when a newline appears in the input.  After
             output is written, at most (OUTSIZE - 1) bytes will remain in the
             buffer.  Now INSIZE bytes of input is read.  Each input character
             may grow by a factor of 4 (by the prepending of M-^).  If all
             characters do, and no newlines appear in this block of input, we
             will have at most (OUTSIZE - 1 + INSIZE * 4) bytes in the buffer.
             If the last character in the preceding block of input was a
             newline, a line number may be written (according to the given
             options) as the first thing in the output buffer. (Done after the
             new input is read, but before processing of the input begins.)
             A line number requires seldom more than LINE_COUNTER_BUF_LEN
             positions.

             Align the output buffer to a page size boundary, for efficiency
             on some paging implementations, so add PAGE_SIZE - 1 bytes to the
             request to make room for the alignment.  */

          outbuf = xmalloc (outsize - 1 + insize * 4 + LINE_COUNTER_BUF_LEN
                            + page_size - 1);

          ok &= cat (ptr_align (inbuf, page_size), insize,
                     ptr_align (outbuf, page_size), outsize, show_nonprinting,
                     show_tabs, number, number_nonblank, show_ends,
                     squeeze_blank);

          free (outbuf);
        }

      free (inbuf);

    contin:
      if (!STREQ (infile, "-") && close (input_desc) < 0)
        {
          error (0, errno, "%s", quotef (infile));
          ok = false;
        }
    }
  while (++argind < argc);

  if (have_read_stdin && close (STDIN_FILENO) < 0)
    die (EXIT_FAILURE, errno, _("closing standard input"));

  return ok ? EXIT_SUCCESS : EXIT_FAILURE;
}