freebsd-dev/usr.bin/look/look.c
Pedro F. Giffuni 8a16b7a18f General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

364 lines
9.4 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* David Hitz of Auspex Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1991, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)look.c 8.2 (Berkeley) 5/4/95";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* look -- find lines in a sorted list.
*
* The man page said that TABs and SPACEs participate in -d comparisons.
* In fact, they were ignored. This implements historic practice, not
* the manual page.
*/
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <limits.h>
#include <locale.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>
#include <wctype.h>
#include "pathnames.h"
static char _path_words[] = _PATH_WORDS;
#define EQUAL 0
#define GREATER 1
#define LESS (-1)
static int dflag, fflag;
static char *binary_search(wchar_t *, unsigned char *, unsigned char *);
static int compare(wchar_t *, unsigned char *, unsigned char *);
static char *linear_search(wchar_t *, unsigned char *, unsigned char *);
static int look(wchar_t *, unsigned char *, unsigned char *);
static wchar_t *prepkey(const char *, wchar_t);
static void print_from(wchar_t *, unsigned char *, unsigned char *);
static void usage(void);
static struct option longopts[] = {
{ "alternative",no_argument, NULL, 'a' },
{ "alphanum", no_argument, NULL, 'd' },
{ "ignore-case",no_argument, NULL, 'i' },
{ "terminate", required_argument, NULL, 't'},
{ NULL, 0, NULL, 0 },
};
int
main(int argc, char *argv[])
{
struct stat sb;
int ch, fd, match;
wchar_t termchar;
unsigned char *back, *front;
unsigned const char *file;
wchar_t *key;
(void) setlocale(LC_CTYPE, "");
file = _path_words;
termchar = L'\0';
while ((ch = getopt_long(argc, argv, "+adft:", longopts, NULL)) != -1)
switch(ch) {
case 'a':
/* COMPATIBILITY */
break;
case 'd':
dflag = 1;
break;
case 'f':
fflag = 1;
break;
case 't':
if (mbrtowc(&termchar, optarg, MB_LEN_MAX, NULL) !=
strlen(optarg))
errx(2, "invalid termination character");
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (argc == 0)
usage();
if (argc == 1) /* But set -df by default. */
dflag = fflag = 1;
key = prepkey(*argv++, termchar);
if (argc >= 2)
file = *argv++;
match = 1;
do {
if ((fd = open(file, O_RDONLY, 0)) < 0 || fstat(fd, &sb))
err(2, "%s", file);
if ((uintmax_t)sb.st_size > (uintmax_t)SIZE_T_MAX)
errx(2, "%s: %s", file, strerror(EFBIG));
if (sb.st_size == 0) {
close(fd);
continue;
}
if ((front = mmap(NULL, (size_t)sb.st_size, PROT_READ, MAP_SHARED, fd, (off_t)0)) == MAP_FAILED)
err(2, "%s", file);
back = front + sb.st_size;
match *= (look(key, front, back));
close(fd);
} while (argc-- > 2 && (file = *argv++));
exit(match);
}
static wchar_t *
prepkey(const char *string, wchar_t termchar)
{
const char *readp;
wchar_t *key, *writep;
wchar_t ch;
size_t clen;
/*
* Reformat search string and convert to wide character representation
* to avoid doing it multiple times later.
*/
if ((key = malloc(sizeof(wchar_t) * (strlen(string) + 1))) == NULL)
err(2, NULL);
readp = string;
writep = key;
while ((clen = mbrtowc(&ch, readp, MB_LEN_MAX, NULL)) != 0) {
if (clen == (size_t)-1 || clen == (size_t)-2)
errc(2, EILSEQ, NULL);
if (fflag)
ch = towlower(ch);
if (!dflag || iswalnum(ch))
*writep++ = ch;
readp += clen;
}
*writep = L'\0';
if (termchar != L'\0' && (writep = wcschr(key, termchar)) != NULL)
*++writep = L'\0';
return (key);
}
static int
look(wchar_t *string, unsigned char *front, unsigned char *back)
{
front = binary_search(string, front, back);
front = linear_search(string, front, back);
if (front)
print_from(string, front, back);
return (front ? 0 : 1);
}
/*
* Binary search for "string" in memory between "front" and "back".
*
* This routine is expected to return a pointer to the start of a line at
* *or before* the first word matching "string". Relaxing the constraint
* this way simplifies the algorithm.
*
* Invariants:
* front points to the beginning of a line at or before the first
* matching string.
*
* back points to the beginning of a line at or after the first
* matching line.
*
* Base of the Invariants.
* front = NULL;
* back = EOF;
*
* Advancing the Invariants:
*
* p = first newline after halfway point from front to back.
*
* If the string at "p" is not greater than the string to match,
* p is the new front. Otherwise it is the new back.
*
* Termination:
*
* The definition of the routine allows it return at any point,
* since front is always at or before the line to print.
*
* In fact, it returns when the chosen "p" equals "back". This
* implies that there exists a string is least half as long as
* (back - front), which in turn implies that a linear search will
* be no more expensive than the cost of simply printing a string or two.
*
* Trying to continue with binary search at this point would be
* more trouble than it's worth.
*/
#define SKIP_PAST_NEWLINE(p, back) \
while (p < back && *p++ != '\n');
static char *
binary_search(wchar_t *string, unsigned char *front, unsigned char *back)
{
unsigned char *p;
p = front + (back - front) / 2;
SKIP_PAST_NEWLINE(p, back);
/*
* If the file changes underneath us, make sure we don't
* infinitely loop.
*/
while (p < back && back > front) {
if (compare(string, p, back) == GREATER)
front = p;
else
back = p;
p = front + (back - front) / 2;
SKIP_PAST_NEWLINE(p, back);
}
return (front);
}
/*
* Find the first line that starts with string, linearly searching from front
* to back.
*
* Return NULL for no such line.
*
* This routine assumes:
*
* o front points at the first character in a line.
* o front is before or at the first line to be printed.
*/
static char *
linear_search(wchar_t *string, unsigned char *front, unsigned char *back)
{
while (front < back) {
switch (compare(string, front, back)) {
case EQUAL: /* Found it. */
return (front);
case LESS: /* No such string. */
return (NULL);
case GREATER: /* Keep going. */
break;
}
SKIP_PAST_NEWLINE(front, back);
}
return (NULL);
}
/*
* Print as many lines as match string, starting at front.
*/
static void
print_from(wchar_t *string, unsigned char *front, unsigned char *back)
{
for (; front < back && compare(string, front, back) == EQUAL; ++front) {
for (; front < back && *front != '\n'; ++front)
if (putchar(*front) == EOF)
err(2, "stdout");
if (putchar('\n') == EOF)
err(2, "stdout");
}
}
/*
* Return LESS, GREATER, or EQUAL depending on how the string1 compares with
* string2 (s1 ??? s2).
*
* o Matches up to len(s1) are EQUAL.
* o Matches up to len(s2) are GREATER.
*
* Compare understands about the -f and -d flags, and treats comparisons
* appropriately.
*
* The string "s1" is null terminated. The string s2 is '\n' terminated (or
* "back" terminated).
*/
static int
compare(wchar_t *s1, unsigned char *s2, unsigned char *back)
{
wchar_t ch1, ch2;
size_t len2;
for (; *s1 && s2 < back && *s2 != '\n'; ++s1, s2 += len2) {
ch1 = *s1;
len2 = mbrtowc(&ch2, s2, back - s2, NULL);
if (len2 == (size_t)-1 || len2 == (size_t)-2) {
ch2 = *s2;
len2 = 1;
}
if (fflag)
ch2 = towlower(ch2);
if (dflag && !iswalnum(ch2)) {
/* Ignore character in comparison. */
--s1;
continue;
}
if (ch1 != ch2)
return (ch1 < ch2 ? LESS : GREATER);
}
return (*s1 ? GREATER : EQUAL);
}
static void
usage(void)
{
(void)fprintf(stderr, "usage: look [-df] [-t char] string [file ...]\n");
exit(2);
}