/* tac - concatenate and print files in reverse
- Copyright (C) 1988-1991, 1995-2006, 2008 Free Software Foundation, Inc.
+ Copyright (C) 1988-2013 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
Options:
-b, --before The separator is attached to the beginning
- of the record that it precedes in the file.
+ of the record that it precedes in the file.
-r, --regex The separator is a regular expression.
-s, --separator=separator Use SEPARATOR as the record separator.
#include <regex.h>
#include "error.h"
+#include "filenamecat.h"
#include "quote.h"
#include "quotearg.h"
#include "safe-read.h"
#include "stdlib--.h"
#include "xfreopen.h"
-/* The official name of this program (e.g., no `g' prefix). */
+/* The official name of this program (e.g., no 'g' prefix). */
#define PROGRAM_NAME "tac"
#define AUTHORS \
/* True if we have ever read standard input. */
static bool have_read_stdin = false;
-/* If true, print `separator' along with the record preceding it
+/* If true, print 'separator' along with the record preceding it
in the file; otherwise with the record following it. */
static bool separator_ends_record;
-/* 0 if `separator' is to be matched as a regular expression;
- otherwise, the length of `separator', used as a sentinel to
+/* 0 if 'separator' is to be matched as a regular expression;
+ otherwise, the length of 'separator', used as a sentinel to
stop the search. */
static size_t sentinel_length;
-/* The length of a match with `separator'. If `sentinel_length' is 0,
- `match_length' is computed every time a match succeeds;
- otherwise, it is simply the length of `separator'. */
+/* The length of a match with 'separator'. If 'sentinel_length' is 0,
+ 'match_length' is computed every time a match succeeds;
+ otherwise, it is simply the length of 'separator'. */
static size_t match_length;
/* The input buffer. */
static char *G_buffer;
-/* The number of bytes to read at once into `buffer'. */
+/* The number of bytes to read at once into 'buffer'. */
static size_t read_size;
-/* The size of `buffer'. This is read_size * 2 + sentinel_length + 2.
- The extra 2 bytes allow `past_end' to have a value beyond the
- end of `G_buffer' and `match_start' to run off the front of `G_buffer'. */
+/* The size of 'buffer'. This is read_size * 2 + sentinel_length + 2.
+ The extra 2 bytes allow 'past_end' to have a value beyond the
+ end of 'G_buffer' and 'match_start' to run off the front of 'G_buffer'. */
static size_t G_buffer_size;
-/* The compiled regular expression representing `separator'. */
+/* The compiled regular expression representing 'separator'. */
static struct re_pattern_buffer compiled_separator;
static char compiled_separator_fastmap[UCHAR_MAX + 1];
static struct re_registers regs;
usage (int status)
{
if (status != EXIT_SUCCESS)
- fprintf (stderr, _("Try `%s --help' for more information.\n"),
- program_name);
+ emit_try_help ();
else
{
printf (_("\
Usage: %s [OPTION]... [FILE]...\n\
"),
- program_name);
+ program_name);
fputs (_("\
Write each FILE to standard output, last line first.\n\
With no FILE, or when FILE is -, read standard input.\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
- emit_bug_reporting_address ();
+ emit_ancillary_info ();
}
exit (status);
}
static bool
tac_seekable (int input_fd, const char *file)
{
- /* Pointer to the location in `G_buffer' where the search for
+ /* Pointer to the location in 'G_buffer' where the search for
the next separator will begin. */
char *match_start;
- /* Pointer to one past the rightmost character in `G_buffer' that
+ /* Pointer to one past the rightmost character in 'G_buffer' that
has not been printed yet. */
char *past_end;
- /* Length of the record growing in `G_buffer'. */
+ /* Length of the record growing in 'G_buffer'. */
size_t saved_record_size;
/* Offset in the file of the next read. */
off_t file_pos;
- /* True if `output' has not been called yet for any file.
+ /* True if 'output' has not been called yet for any file.
Only used when the separator is attached to the preceding record. */
bool first_time = true;
char first_char = *separator; /* Speed optimization, non-regexp. */
size_t match_length1 = match_length - 1; /* Speed optimization, non-regexp. */
/* Find the size of the input file. */
- file_pos = lseek (input_fd, (off_t) 0, SEEK_END);
+ file_pos = lseek (input_fd, 0, SEEK_END);
if (file_pos < 1)
return true; /* It's an empty file. */
/* Arrange for the first read to lop off enough to leave the rest of the
- file a multiple of `read_size'. Since `read_size' can change, this may
+ file a multiple of 'read_size'. Since 'read_size' can change, this may
not always hold during the program run, but since it usually will, leave
it here for i/o efficiency (page/sector boundaries and all that).
Note: the efficiency gain has not been verified. */
if (saved_record_size == 0)
saved_record_size = read_size;
file_pos -= saved_record_size;
- /* `file_pos' now points to the start of the last (probably partial) block
+ /* 'file_pos' now points to the start of the last (probably partial) block
in the input file. */
if (lseek (input_fd, file_pos, SEEK_SET) < 0)
if (sentinel_length)
match_start -= match_length1;
- for (;;)
+ while (true)
{
- /* Search backward from `match_start' - 1 to `G_buffer' for a match
- with `separator'; for speed, use strncmp if `separator' contains no
- metacharacters.
- If the match succeeds, set `match_start' to point to the start of
- the match and `match_length' to the length of the match.
- Otherwise, make `match_start' < `G_buffer'. */
+ /* Search backward from 'match_start' - 1 to 'G_buffer' for a match
+ with 'separator'; for speed, use strncmp if 'separator' contains no
+ metacharacters.
+ If the match succeeds, set 'match_start' to point to the start of
+ the match and 'match_length' to the length of the match.
+ Otherwise, make 'match_start' < 'G_buffer'. */
if (sentinel_length == 0)
- {
- size_t i = match_start - G_buffer;
- regoff_t ri = i;
- regoff_t range = 1 - ri;
- regoff_t ret;
-
- if (1 < range)
- error (EXIT_FAILURE, 0, _("record too large"));
-
- if (range == 1
- || ((ret = re_search (&compiled_separator, G_buffer,
- i, i - 1, range, ®s))
- == -1))
- match_start = G_buffer - 1;
- else if (ret == -2)
- {
- error (EXIT_FAILURE, 0,
- _("error in regular expression search"));
- }
- else
- {
- match_start = G_buffer + regs.start[0];
- match_length = regs.end[0] - regs.start[0];
- }
- }
+ {
+ size_t i = match_start - G_buffer;
+ regoff_t ri = i;
+ regoff_t range = 1 - ri;
+ regoff_t ret;
+
+ if (1 < range)
+ error (EXIT_FAILURE, 0, _("record too large"));
+
+ if (range == 1
+ || ((ret = re_search (&compiled_separator, G_buffer,
+ i, i - 1, range, ®s))
+ == -1))
+ match_start = G_buffer - 1;
+ else if (ret == -2)
+ {
+ error (EXIT_FAILURE, 0,
+ _("error in regular expression search"));
+ }
+ else
+ {
+ match_start = G_buffer + regs.start[0];
+ match_length = regs.end[0] - regs.start[0];
+ }
+ }
else
- {
- /* `match_length' is constant for non-regexp boundaries. */
- while (*--match_start != first_char
- || (match_length1 && strncmp (match_start + 1, separator1,
- match_length1)))
- /* Do nothing. */ ;
- }
-
- /* Check whether we backed off the front of `G_buffer' without finding
- a match for `separator'. */
+ {
+ /* 'match_length' is constant for non-regexp boundaries. */
+ while (*--match_start != first_char
+ || (match_length1 && strncmp (match_start + 1, separator1,
+ match_length1)))
+ /* Do nothing. */ ;
+ }
+
+ /* Check whether we backed off the front of 'G_buffer' without finding
+ a match for 'separator'. */
if (match_start < G_buffer)
- {
- if (file_pos == 0)
- {
- /* Hit the beginning of the file; print the remaining record. */
- output (G_buffer, past_end);
- return true;
- }
-
- saved_record_size = past_end - G_buffer;
- if (saved_record_size > read_size)
- {
- /* `G_buffer_size' is about twice `read_size', so since
- we want to read in another `read_size' bytes before
- the data already in `G_buffer', we need to increase
- `G_buffer_size'. */
- char *newbuffer;
- size_t offset = sentinel_length ? sentinel_length : 1;
- ptrdiff_t match_start_offset = match_start - G_buffer;
- ptrdiff_t past_end_offset = past_end - G_buffer;
- size_t old_G_buffer_size = G_buffer_size;
-
- read_size *= 2;
- G_buffer_size = read_size * 2 + sentinel_length + 2;
- if (G_buffer_size < old_G_buffer_size)
- xalloc_die ();
- newbuffer = xrealloc (G_buffer - offset, G_buffer_size);
- newbuffer += offset;
- /* Adjust the pointers for the new buffer location. */
- match_start = newbuffer + match_start_offset;
- past_end = newbuffer + past_end_offset;
- G_buffer = newbuffer;
- }
-
- /* Back up to the start of the next bufferfull of the file. */
- if (file_pos >= read_size)
- file_pos -= read_size;
- else
- {
- read_size = file_pos;
- file_pos = 0;
- }
- if (lseek (input_fd, file_pos, SEEK_SET) < 0)
- error (0, errno, _("%s: seek failed"), quotearg_colon (file));
-
- /* Shift the pending record data right to make room for the new.
- The source and destination regions probably overlap. */
- memmove (G_buffer + read_size, G_buffer, saved_record_size);
- past_end = G_buffer + read_size + saved_record_size;
- /* For non-regexp searches, avoid unneccessary scanning. */
- if (sentinel_length)
- match_start = G_buffer + read_size;
- else
- match_start = past_end;
-
- if (safe_read (input_fd, G_buffer, read_size) != read_size)
- {
- error (0, errno, _("%s: read error"), quotearg_colon (file));
- return false;
- }
- }
+ {
+ if (file_pos == 0)
+ {
+ /* Hit the beginning of the file; print the remaining record. */
+ output (G_buffer, past_end);
+ return true;
+ }
+
+ saved_record_size = past_end - G_buffer;
+ if (saved_record_size > read_size)
+ {
+ /* 'G_buffer_size' is about twice 'read_size', so since
+ we want to read in another 'read_size' bytes before
+ the data already in 'G_buffer', we need to increase
+ 'G_buffer_size'. */
+ char *newbuffer;
+ size_t offset = sentinel_length ? sentinel_length : 1;
+ ptrdiff_t match_start_offset = match_start - G_buffer;
+ ptrdiff_t past_end_offset = past_end - G_buffer;
+ size_t old_G_buffer_size = G_buffer_size;
+
+ read_size *= 2;
+ G_buffer_size = read_size * 2 + sentinel_length + 2;
+ if (G_buffer_size < old_G_buffer_size)
+ xalloc_die ();
+ newbuffer = xrealloc (G_buffer - offset, G_buffer_size);
+ newbuffer += offset;
+ /* Adjust the pointers for the new buffer location. */
+ match_start = newbuffer + match_start_offset;
+ past_end = newbuffer + past_end_offset;
+ G_buffer = newbuffer;
+ }
+
+ /* Back up to the start of the next bufferfull of the file. */
+ if (file_pos >= read_size)
+ file_pos -= read_size;
+ else
+ {
+ read_size = file_pos;
+ file_pos = 0;
+ }
+ if (lseek (input_fd, file_pos, SEEK_SET) < 0)
+ error (0, errno, _("%s: seek failed"), quotearg_colon (file));
+
+ /* Shift the pending record data right to make room for the new.
+ The source and destination regions probably overlap. */
+ memmove (G_buffer + read_size, G_buffer, saved_record_size);
+ past_end = G_buffer + read_size + saved_record_size;
+ /* For non-regexp searches, avoid unnecessary scanning. */
+ if (sentinel_length)
+ match_start = G_buffer + read_size;
+ else
+ match_start = past_end;
+
+ if (safe_read (input_fd, G_buffer, read_size) != read_size)
+ {
+ error (0, errno, _("%s: read error"), quotearg_colon (file));
+ return false;
+ }
+ }
else
- {
- /* Found a match of `separator'. */
- if (separator_ends_record)
- {
- char *match_end = match_start + match_length;
-
- /* If this match of `separator' isn't at the end of the
- file, print the record. */
- if (!first_time || match_end != past_end)
- output (match_end, past_end);
- past_end = match_end;
- first_time = false;
- }
- else
- {
- output (match_start, past_end);
- past_end = match_start;
- }
-
- /* For non-regex matching, we can back up. */
- if (sentinel_length > 0)
- match_start -= match_length - 1;
- }
+ {
+ /* Found a match of 'separator'. */
+ if (separator_ends_record)
+ {
+ char *match_end = match_start + match_length;
+
+ /* If this match of 'separator' isn't at the end of the
+ file, print the record. */
+ if (!first_time || match_end != past_end)
+ output (match_end, past_end);
+ past_end = match_end;
+ first_time = false;
+ }
+ else
+ {
+ output (match_start, past_end);
+ past_end = match_start;
+ }
+
+ /* For non-regex matching, we can back up. */
+ if (sentinel_length > 0)
+ match_start -= match_length - 1;
+ }
}
}
#endif
-/* Copy from file descriptor INPUT_FD (corresponding to the named FILE) to
- a temporary file, and set *G_TMP and *G_TEMPFILE to the resulting stream
- and file name. Return true if successful. */
-
+/* A wrapper around mkstemp that gives us both an open stream pointer,
+ FP, and the corresponding FILE_NAME. Always return the same FP/name
+ pair, rewinding/truncating it upon each reuse. */
static bool
-copy_to_temp (FILE **g_tmp, char **g_tempfile, int input_fd, char const *file)
+temp_stream (FILE **fp, char **file_name)
{
- static char *template = NULL;
- static char const *tempdir;
- char *tempfile;
- FILE *tmp;
- int fd;
-
- if (template == NULL)
+ static char *tempfile = NULL;
+ static FILE *tmp_fp;
+ if (tempfile == NULL)
{
- char const * const Template = "%s/tacXXXXXX";
- tempdir = getenv ("TMPDIR");
+ char const *t = getenv ("TMPDIR");
+ char const *tempdir = t ? t : DEFAULT_TMPDIR;
+ tempfile = mfile_name_concat (tempdir, "tacXXXXXX", NULL);
if (tempdir == NULL)
- tempdir = DEFAULT_TMPDIR;
-
- /* Subtract 2 for `%s' and add 1 for the trailing NUL byte. */
- template = xmalloc (strlen (tempdir) + strlen (Template) - 2 + 1);
- sprintf (template, Template, tempdir);
+ {
+ error (0, 0, _("memory exhausted"));
+ return false;
+ }
+
+ /* FIXME: there's a small window between a successful mkstemp call
+ and the unlink that's performed by record_or_unlink_tempfile.
+ If we're interrupted in that interval, this code fails to remove
+ the temporary file. On systems that define DONT_UNLINK_WHILE_OPEN,
+ the window is much larger -- it extends to the atexit-called
+ unlink_tempfile.
+ FIXME: clean up upon fatal signal. Don't block them, in case
+ $TMPFILE is a remote file system. */
+
+ int fd = mkstemp (tempfile);
+ if (fd < 0)
+ {
+ error (0, errno, _("failed to create temporary file in %s"),
+ quote (tempdir));
+ goto Reset;
+ }
+
+ tmp_fp = fdopen (fd, (O_BINARY ? "w+b" : "w+"));
+ if (! tmp_fp)
+ {
+ error (0, errno, _("failed to open %s for writing"),
+ quote (tempfile));
+ close (fd);
+ unlink (tempfile);
+ Reset:
+ free (tempfile);
+ tempfile = NULL;
+ return false;
+ }
+
+ record_or_unlink_tempfile (tempfile, tmp_fp);
}
-
- /* FIXME: there's a small window between a successful mkstemp call
- and the unlink that's performed by record_or_unlink_tempfile.
- If we're interrupted in that interval, this code fails to remove
- the temporary file. On systems that define DONT_UNLINK_WHILE_OPEN,
- the window is much larger -- it extends to the atexit-called
- unlink_tempfile.
- FIXME: clean up upon fatal signal. Don't block them, in case
- $TMPFILE is a remote file system. */
-
- tempfile = template;
- fd = mkstemp (template);
- if (fd < 0)
+ else
{
- error (0, errno, _("cannot create temporary file in %s"),
- quote (tempdir));
- return false;
+ if (fseeko (tmp_fp, 0, SEEK_SET) < 0
+ || ftruncate (fileno (tmp_fp), 0) < 0)
+ {
+ error (0, errno, _("failed to rewind stream for %s"),
+ quote (tempfile));
+ return false;
+ }
}
- tmp = fdopen (fd, (O_BINARY ? "w+b" : "w+"));
- if (! tmp)
- {
- error (0, errno, _("cannot open %s for writing"), quote (tempfile));
- close (fd);
- unlink (tempfile);
- return false;
- }
+ *fp = tmp_fp;
+ *file_name = tempfile;
+ return true;
+}
+
+/* Copy from file descriptor INPUT_FD (corresponding to the named FILE) to
+ a temporary file, and set *G_TMP and *G_TEMPFILE to the resulting stream
+ and file name. Return true if successful. */
- record_or_unlink_tempfile (tempfile, tmp);
+static bool
+copy_to_temp (FILE **g_tmp, char **g_tempfile, int input_fd, char const *file)
+{
+ FILE *fp;
+ char *file_name;
+ if (!temp_stream (&fp, &file_name))
+ return false;
while (1)
{
size_t bytes_read = safe_read (input_fd, G_buffer, read_size);
if (bytes_read == 0)
- break;
+ break;
if (bytes_read == SAFE_READ_ERROR)
- {
- error (0, errno, _("%s: read error"), quotearg_colon (file));
- goto Fail;
- }
-
- if (fwrite (G_buffer, 1, bytes_read, tmp) != bytes_read)
- {
- error (0, errno, _("%s: write error"), quotearg_colon (tempfile));
- goto Fail;
- }
+ {
+ error (0, errno, _("%s: read error"), quotearg_colon (file));
+ goto Fail;
+ }
+
+ if (fwrite (G_buffer, 1, bytes_read, fp) != bytes_read)
+ {
+ error (0, errno, _("%s: write error"), quotearg_colon (file_name));
+ goto Fail;
+ }
}
- if (fflush (tmp) != 0)
+ if (fflush (fp) != 0)
{
- error (0, errno, _("%s: write error"), quotearg_colon (tempfile));
+ error (0, errno, _("%s: write error"), quotearg_colon (file_name));
goto Fail;
}
- *g_tmp = tmp;
- *g_tempfile = tempfile;
+ *g_tmp = fp;
+ *g_tempfile = file_name;
return true;
Fail:
- fclose (tmp);
+ fclose (fp);
return false;
}
{
FILE *tmp_stream;
char *tmp_file;
- return (copy_to_temp (&tmp_stream, &tmp_file, input_fd, file)
- && tac_seekable (fileno (tmp_stream), tmp_file));
+ if (!copy_to_temp (&tmp_stream, &tmp_file, input_fd, file))
+ return false;
+
+ bool ok = tac_seekable (fileno (tmp_stream), tmp_file);
+ return ok;
}
/* Print FILE in reverse, copying it to a temporary
fd = STDIN_FILENO;
filename = _("standard input");
if (O_BINARY && ! isatty (STDIN_FILENO))
- xfreopen (NULL, "rb", stdin);
+ xfreopen (NULL, "rb", stdin);
}
else
{
fd = open (filename, O_RDONLY | O_BINARY);
if (fd < 0)
- {
- error (0, errno, _("cannot open %s for reading"), quote (filename));
- return false;
- }
+ {
+ error (0, errno, _("failed to open %s for reading"),
+ quote (filename));
+ return false;
+ }
}
- file_size = lseek (fd, (off_t) 0, SEEK_END);
+ file_size = lseek (fd, 0, SEEK_END);
ok = (file_size < 0 || isatty (fd)
- ? tac_nonseekable (fd, filename)
- : tac_seekable (fd, filename));
+ ? tac_nonseekable (fd, filename)
+ : tac_seekable (fd, filename));
if (!is_stdin && close (fd) != 0)
{
while ((optc = getopt_long (argc, argv, "brs:", longopts, NULL)) != -1)
{
switch (optc)
- {
- case 'b':
- separator_ends_record = false;
- break;
- case 'r':
- sentinel_length = 0;
- break;
- case 's':
- separator = optarg;
- if (*separator == 0)
- error (EXIT_FAILURE, 0, _("separator cannot be empty"));
- break;
- case_GETOPT_HELP_CHAR;
- case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
- default:
- usage (EXIT_FAILURE);
- }
+ {
+ case 'b':
+ separator_ends_record = false;
+ break;
+ case 'r':
+ sentinel_length = 0;
+ break;
+ case 's':
+ separator = optarg;
+ if (*separator == 0)
+ error (EXIT_FAILURE, 0, _("separator cannot be empty"));
+ break;
+ case_GETOPT_HELP_CHAR;
+ case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
+ default:
+ usage (EXIT_FAILURE);
+ }
}
if (sentinel_length == 0)
compiled_separator.fastmap = compiled_separator_fastmap;
compiled_separator.translate = NULL;
error_message = re_compile_pattern (separator, strlen (separator),
- &compiled_separator);
+ &compiled_separator);
if (error_message)
- error (EXIT_FAILURE, 0, "%s", error_message);
+ error (EXIT_FAILURE, 0, "%s", error_message);
}
else
match_length = sentinel_length = strlen (separator);
while (sentinel_length >= read_size / 2)
{
if (SIZE_MAX / 2 < read_size)
- xalloc_die ();
+ xalloc_die ();
read_size *= 2;
}
half_buffer_size = read_size + sentinel_length + 1;
G_buffer = xmalloc (G_buffer_size);
if (sentinel_length)
{
- strcpy (G_buffer, separator);
+ memcpy (G_buffer, separator, sentinel_length + 1);
G_buffer += sentinel_length;
}
else
}
file = (optind < argc
- ? (char const *const *) &argv[optind]
- : default_file_list);
+ ? (char const *const *) &argv[optind]
+ : default_file_list);
if (O_BINARY && ! isatty (STDOUT_FILENO))
xfreopen (NULL, "wb", stdout);
output ((char *) NULL, (char *) NULL);
if (have_read_stdin && close (STDIN_FILENO) < 0)
- error (EXIT_FAILURE, errno, "-");
+ {
+ error (0, errno, "-");
+ ok = false;
+ }
+
+#ifdef lint
+ size_t offset = sentinel_length ? sentinel_length : 1;
+ free (G_buffer - offset);
+#endif
+
exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
}
projects / platform / upstream / coreutils.git / blobdiff