1/*	$NetBSD: csplit.c,v 1.7 2017/07/30 23:02:53 cheusov Exp $	*/
2/*	$FreeBSD: src/usr.bin/csplit/csplit.c,v 1.9 2004/03/22 11:15:03 tjr Exp$	*/
3
4/*-
5 * Copyright (c) 2002 Tim J. Robbins.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30/*
31 * csplit -- split files based on context
32 *
33 * This utility splits its input into numbered output files by line number
34 * or by a regular expression. Regular expression matches have an optional
35 * offset with them, allowing the split to occur a specified number of
36 * lines before or after the match.
37 *
38 * To handle negative offsets, we stop reading when the match occurs and
39 * store the offset that the file should have been split at, then use
40 * this output file as input until all the "overflowed" lines have been read.
41 * The file is then closed and truncated to the correct length.
42 *
43 * We assume that the output files can be seeked upon (ie. they cannot be
44 * symlinks to named pipes or character devices), but make no such
45 * assumption about the input.
46 */
47
48#include <sys/cdefs.h>
49#ifndef lint
50__RCSID("$NetBSD: csplit.c,v 1.7 2017/07/30 23:02:53 cheusov Exp $");
51#endif
52
53#include <sys/types.h>
54
55#include <ctype.h>
56#include <err.h>
57#include <errno.h>
58#include <limits.h>
59#include <locale.h>
60#include <regex.h>
61#include <signal.h>
62#include <stdint.h>
63#include <stdio.h>
64#include <stdlib.h>
65#include <string.h>
66#include <unistd.h>
67#include <util.h>
68
69static void	 cleanup(void);
70static void	 do_lineno(const char *);
71static void	 do_rexp(const char *);
72static char	*get_line(void);
73static void	 handlesig(int);
74static FILE	*newfile(void);
75static void	 toomuch(FILE *, long);
76static void	 usage(void) __dead;
77
78/*
79 * Command line options
80 */
81static const char *prefix;		/* File name prefix */
82static long	 sufflen;		/* Number of decimal digits for suffix */
83static int	 sflag;			/* Suppress output of file names */
84static int	 kflag;			/* Keep output if error occurs */
85
86/*
87 * Other miscellaneous globals (XXX too many)
88 */
89static long	 lineno;		/* Current line number in input file */
90static long	 reps;			/* Number of repetitions for this pattern */
91static long	 nfiles;		/* Number of files output so far */
92static long	 maxfiles;		/* Maximum number of files we can create */
93static char	 currfile[PATH_MAX];	/* Current output file */
94static const char *infn;		/* Name of the input file */
95static FILE	*infile;		/* Input file handle */
96static FILE	*overfile;		/* Overflow file for toomuch() */
97static off_t	 truncofs;		/* Offset this file should be truncated at */
98static int	 doclean;		/* Should cleanup() remove output? */
99
100int
101main(int argc, char *argv[])
102{
103	struct sigaction sa;
104	long i;
105	int ch;
106	const char *expr;
107	char *ep, *p;
108	FILE *ofp;
109
110	(void)setlocale(LC_ALL, "");
111
112	kflag = sflag = 0;
113	prefix = "xx";
114	sufflen = 2;
115	while ((ch = getopt(argc, argv, "ksf:n:")) > 0) {
116		switch (ch) {
117		case 'f':
118			prefix = optarg;
119			break;
120		case 'k':
121			kflag = 1;
122			break;
123		case 'n':
124			errno = 0;
125			sufflen = strtol(optarg, &ep, 10);
126			if (sufflen <= 0 || *ep != '\0' || errno != 0)
127				errx(1, "%s: bad suffix length", optarg);
128			break;
129		case 's':
130			sflag = 1;
131			break;
132		default:
133			usage();
134			/*NOTREACHED*/
135		}
136	}
137
138	if (sufflen + strlen(prefix) >= PATH_MAX)
139		errx(1, "name too long");
140
141	argc -= optind;
142	argv += optind;
143
144	if ((infn = *argv++) == NULL)
145		usage();
146	if (strcmp(infn, "-") == 0) {
147		infile = stdin;
148		infn = "stdin";
149	} else if ((infile = fopen(infn, "r")) == NULL)
150		err(1, "%s", infn);
151
152	if (!kflag) {
153		doclean = 1;
154		(void)atexit(cleanup);
155		sa.sa_flags = 0;
156		sa.sa_handler = handlesig;
157		(void)sigemptyset(&sa.sa_mask);
158		(void)sigaddset(&sa.sa_mask, SIGHUP);
159		(void)sigaddset(&sa.sa_mask, SIGINT);
160		(void)sigaddset(&sa.sa_mask, SIGTERM);
161		(void)sigaction(SIGHUP, &sa, NULL);
162		(void)sigaction(SIGINT, &sa, NULL);
163		(void)sigaction(SIGTERM, &sa, NULL);
164	}
165
166	lineno = 0;
167	nfiles = 0;
168	truncofs = 0;
169	overfile = NULL;
170
171	/* Ensure 10^sufflen < LONG_MAX. */
172	for (maxfiles = 1, i = 0; i < sufflen; i++) {
173		if (maxfiles > LONG_MAX / 10)
174			errx(1, "%ld: suffix too long (limit %ld)",
175			    sufflen, i);
176		maxfiles *= 10;
177	}
178
179	/* Create files based on supplied patterns. */
180	while (nfiles < maxfiles - 1 && (expr = *argv++) != NULL) {
181		/* Look ahead & see if this pattern has any repetitions. */
182		if (*argv != NULL && **argv == '{') {
183			errno = 0;
184			reps = strtol(*argv + 1, &ep, 10);
185			if (reps < 0 || *ep != '}' || errno != 0)
186				errx(1, "%s: bad repetition count", *argv + 1);
187			argv++;
188		} else
189			reps = 0;
190
191		if (*expr == '/' || *expr == '%') {
192			do
193				do_rexp(expr);
194			while (reps-- != 0 && nfiles < maxfiles - 1);
195		} else if (isdigit((unsigned char)*expr))
196			do_lineno(expr);
197		else
198			errx(1, "%s: unrecognised pattern", expr);
199	}
200
201	/* Copy the rest into a new file. */
202	if (!feof(infile)) {
203		ofp = newfile();
204		while ((p = get_line()) != NULL && fputs(p, ofp) != EOF)
205			;
206		if (!sflag)
207			(void)printf("%jd\n", (intmax_t)ftello(ofp));
208		if (fclose(ofp) != 0)
209			err(1, "%s", currfile);
210	}
211
212	toomuch(NULL, 0L);
213	doclean = 0;
214
215	return (0);
216}
217
218static void
219usage(void)
220{
221
222	(void)fprintf(stderr,
223"Usage: %s [-ks] [-f prefix] [-n number] file args ...\n", getprogname());
224	exit(1);
225}
226
227__dead static void
228handlesig(int sig)
229{
230	char msg[BUFSIZ];
231	size_t len;
232
233	len = snprintf(msg, sizeof(msg), "%s: Caught %s, cleaning up\n",
234	    getprogname(), strsignal(sig));
235	if (len < sizeof(msg))
236		(void)write(STDERR_FILENO, msg, len);
237	cleanup();
238	(void)raise_default_signal(sig);
239	_exit(2);
240}
241
242/* Create a new output file. */
243static FILE *
244newfile(void)
245{
246	FILE *fp;
247
248	if ((size_t)snprintf(currfile, sizeof(currfile), "%s%0*ld", prefix,
249	    (int)sufflen, nfiles) >= sizeof(currfile))
250		errx(1, "%s: %s", currfile, strerror(ENAMETOOLONG));
251	if ((fp = fopen(currfile, "w+")) == NULL)
252		err(1, "%s", currfile);
253	nfiles++;
254
255	return (fp);
256}
257
258/* Remove partial output, called before exiting. */
259static void
260cleanup(void)
261{
262	char fnbuf[PATH_MAX];
263	long i;
264
265	if (!doclean)
266		return;
267
268	/*
269	 * NOTE: One cannot portably assume to be able to call snprintf()
270	 * from inside a signal handler. It does, however, appear to be safe
271	 * to do on FreeBSD and NetBSD. The solution to this problem is worse
272	 * than the problem itself.
273	 */
274
275	for (i = 0; i < nfiles; i++) {
276		(void)snprintf(fnbuf, sizeof(fnbuf), "%s%0*ld", prefix,
277		    (int)sufflen, i);
278		(void)unlink(fnbuf);
279	}
280}
281
282/* Read a line from the input into a static buffer. */
283static char *
284get_line(void)
285{
286	static char lbuf[LINE_MAX];
287	FILE *src;
288
289	src = overfile != NULL ? overfile : infile;
290
291again: if (fgets(lbuf, sizeof(lbuf), src) == NULL) {
292		if (src == overfile) {
293			src = infile;
294			goto again;
295		}
296		return (NULL);
297	}
298	if (ferror(src))
299		err(1, "%s", infn);
300	lineno++;
301
302	return (lbuf);
303}
304
305/* Conceptually rewind the input (as obtained by get_line()) back `n' lines. */
306static void
307toomuch(FILE *ofp, long n)
308{
309	char buf[BUFSIZ];
310	size_t i, nread;
311
312	if (overfile != NULL) {
313		/*
314		 * Truncate the previous file we overflowed into back to
315		 * the correct length, close it.
316		 */
317		if (fflush(overfile) != 0)
318			err(1, "overflow");
319		if (ftruncate(fileno(overfile), truncofs) != 0)
320			err(1, "overflow");
321		if (fclose(overfile) != 0)
322			err(1, "overflow");
323		overfile = NULL;
324	}
325
326	if (n == 0)
327		/* Just tidying up */
328		return;
329
330	lineno -= n;
331
332	/*
333	 * Wind the overflow file backwards to `n' lines before the
334	 * current one.
335	 */
336	do {
337		if (ftello(ofp) < (off_t)sizeof(buf))
338			rewind(ofp);
339		else
340			(void)fseeko(ofp, -(off_t)sizeof(buf), SEEK_CUR);
341		if (ferror(ofp))
342			errx(1, "%s: can't seek", currfile);
343		if ((nread = fread(buf, 1, sizeof(buf), ofp)) == 0)
344			errx(1, "can't read overflowed output");
345		if (fseeko(ofp, -(off_t)nread, SEEK_CUR) != 0)
346			err(1, "%s", currfile);
347		for (i = 1; i <= nread; i++)
348			if (buf[nread - i] == '\n' && n-- == 0)
349				break;
350		if (ftello(ofp) == 0)
351			break;
352	} while (n > 0);
353	if (fseeko(ofp, (off_t)nread - i + 1, SEEK_CUR) != 0)
354		err(1, "%s", currfile);
355
356	/*
357	 * get_line() will read from here. Next call will truncate to
358	 * truncofs in this file.
359	 */
360	overfile = ofp;
361	truncofs = ftello(overfile);
362}
363
364/* Handle splits for /regexp/ and %regexp% patterns. */
365static void
366do_rexp(const char *expr)
367{
368	regex_t cre;
369	intmax_t nwritten;
370	long ofs;
371	int first;
372	char *ecopy, *ep, *p, *pofs, *re;
373	FILE *ofp;
374
375	if ((ecopy = strdup(expr)) == NULL)
376		err(1, "strdup");
377
378	re = ecopy + 1;
379	if ((pofs = strrchr(ecopy, *expr)) == NULL || pofs[-1] == '\\')
380		errx(1, "%s: missing trailing %c", expr, *expr);
381	*pofs++ = '\0';
382
383	if (*pofs != '\0') {
384		errno = 0;
385		ofs = strtol(pofs, &ep, 10);
386		if (*ep != '\0' || errno != 0)
387			errx(1, "%s: bad offset", pofs);
388	} else
389		ofs = 0;
390
391	if (regcomp(&cre, re, REG_BASIC|REG_NOSUB) != 0)
392		errx(1, "%s: bad regular expression", re);
393
394	if (*expr == '/')
395		/* /regexp/: Save results to a file. */
396		ofp = newfile();
397	else {
398		/* %regexp%: Make a temporary file for overflow. */
399		if ((ofp = tmpfile()) == NULL)
400			err(1, "tmpfile");
401	}
402
403	/* Read and output lines until we get a match. */
404	first = 1;
405	while ((p = get_line()) != NULL) {
406		if (fputs(p, ofp) == EOF)
407			break;
408		if (!first && regexec(&cre, p, 0, NULL, 0) == 0)
409			break;
410		first = 0;
411	}
412
413	if (p == NULL)
414		errx(1, "%s: no match", re);
415
416	if (ofs <= 0) {
417		/*
418		 * Negative (or zero) offset: throw back any lines we should
419		 * not have read yet.
420		  */
421		if (p != NULL) {
422			toomuch(ofp, -ofs + 1);
423			nwritten = (intmax_t)truncofs;
424		} else
425			nwritten = (intmax_t)ftello(ofp);
426	} else {
427		/*
428		 * Positive offset: copy the requested number of lines
429		 * after the match.
430		 */
431		while (--ofs > 0 && (p = get_line()) != NULL)
432			if (fputs(p, ofp) == EOF)
433				break;
434		toomuch(NULL, 0L);
435		nwritten = (intmax_t)ftello(ofp);
436		if (fclose(ofp) != 0)
437			err(1, "%s", currfile);
438	}
439
440	if (!sflag && *expr == '/')
441		(void)printf("%jd\n", nwritten);
442
443	regfree(&cre);
444	free(ecopy);
445}
446
447/* Handle splits based on line number. */
448static void
449do_lineno(const char *expr)
450{
451	long lastline, tgtline;
452	char *ep, *p;
453	FILE *ofp;
454
455	errno = 0;
456	tgtline = strtol(expr, &ep, 10);
457	if (tgtline <= 0 || errno != 0 || *ep != '\0')
458		errx(1, "%s: bad line number", expr);
459	lastline = tgtline;
460	if (lastline <= lineno)
461		errx(1, "%s: can't go backwards", expr);
462
463	while (nfiles < maxfiles - 1) {
464		ofp = newfile();
465		while (lineno + 1 != lastline) {
466			if ((p = get_line()) == NULL)
467				errx(1, "%ld: out of range", lastline);
468			if (fputs(p, ofp) == EOF)
469				break;
470		}
471		if (!sflag)
472			(void)printf("%jd\n", (intmax_t)ftello(ofp));
473		if (fclose(ofp) != 0)
474			err(1, "%s", currfile);
475		if (reps-- == 0)
476			break;
477		lastline += tgtline;
478	}
479}
480