xref: /dragonfly/usr.bin/csplit/csplit.c (revision 6d08986d)
1 /*-
2  * Copyright (c) 2002 Tim J. Robbins.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD: src/usr.bin/csplit/csplit.c,v 1.9 2004/03/22 11:15:03 tjr Exp $
27  */
28 
29 /*
30  * csplit -- split files based on context
31  *
32  * This utility splits its input into numbered output files by line number
33  * or by a regular expression. Regular expression matches have an optional
34  * offset with them, allowing the split to occur a specified number of
35  * lines before or after the match.
36  *
37  * To handle negative offsets, we stop reading when the match occurs and
38  * store the offset that the file should have been split at, then use
39  * this output file as input until all the "overflowed" lines have been read.
40  * The file is then closed and truncated to the correct length.
41  *
42  * We assume that the output files can be seeked upon (ie. they cannot be
43  * symlinks to named pipes or character devices), but make no such
44  * assumption about the input.
45  */
46 
47 #include <sys/types.h>
48 
49 #include <ctype.h>
50 #include <err.h>
51 #include <errno.h>
52 #include <limits.h>
53 #include <locale.h>
54 #include <regex.h>
55 #include <signal.h>
56 #include <stdint.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <unistd.h>
61 
62 static void	 cleanup(void);
63 static void	 do_lineno(const char *);
64 static void	 do_rexp(const char *);
65 static char	*get_line(void);
66 static void	 handlesig(int) __dead2;
67 static FILE	*newfile(void);
68 static void	 toomuch(FILE *, long);
69 static void	 usage(void) __dead2;
70 
71 /*
72  * Command line options
73  */
74 static const char *prefix;	/* File name prefix */
75 static long	 sufflen;	/* Number of decimal digits for suffix */
76 static int	 sflag;		/* Suppress output of file names */
77 static int	 kflag;		/* Keep output if error occurs */
78 
79 /*
80  * Other miscellaneous globals (XXX too many)
81  */
82 static long	 lineno;	/* Current line number in input file */
83 static long	 reps;		/* Number of repetitions for this pattern */
84 static long	 nfiles;	/* Number of files output so far */
85 static long	 maxfiles;	/* Maximum number of files we can create */
86 static char	 currfile[PATH_MAX]; /* Current output file */
87 static const char *infn;	/* Name of the input file */
88 static FILE	*infile;	/* Input file handle */
89 static FILE	*overfile;	/* Overflow file for toomuch() */
90 static off_t	 truncofs;	/* Offset this file should be truncated at */
91 static int	 doclean;	/* Should cleanup() remove output? */
92 
93 int
main(int argc,char * argv[])94 main(int argc, char *argv[])
95 {
96 	struct sigaction sa;
97 	long i;
98 	int ch;
99 	const char *expr;
100 	char *ep, *p;
101 	FILE *ofp;
102 
103 	setlocale(LC_ALL, "");
104 
105 	kflag = sflag = 0;
106 	prefix = "xx";
107 	sufflen = 2;
108 	while ((ch = getopt(argc, argv, "ksf:n:")) > 0) {
109 		switch (ch) {
110 		case 'f':
111 			prefix = optarg;
112 			break;
113 		case 'k':
114 			kflag = 1;
115 			break;
116 		case 'n':
117 			errno = 0;
118 			sufflen = strtol(optarg, &ep, 10);
119 			if (sufflen <= 0 || *ep != '\0' || errno != 0)
120 				errx(1, "%s: bad suffix length", optarg);
121 			break;
122 		case 's':
123 			sflag = 1;
124 			break;
125 		default:
126 			usage();
127 			/*NOTREACHED*/
128 		}
129 	}
130 
131 	if (sufflen + strlen(prefix) >= PATH_MAX)
132 		errx(1, "name too long");
133 
134 	argc -= optind;
135 	argv += optind;
136 
137 	if ((infn = *argv++) == NULL)
138 		usage();
139 	if (strcmp(infn, "-") == 0) {
140 		infile = stdin;
141 		infn = "stdin";
142 	} else if ((infile = fopen(infn, "r")) == NULL)
143 		err(1, "%s", infn);
144 
145 	if (!kflag) {
146 		doclean = 1;
147 		atexit(cleanup);
148 		sa.sa_flags = 0;
149 		sa.sa_handler = handlesig;
150 		sigemptyset(&sa.sa_mask);
151 		sigaddset(&sa.sa_mask, SIGHUP);
152 		sigaddset(&sa.sa_mask, SIGINT);
153 		sigaddset(&sa.sa_mask, SIGTERM);
154 		sigaction(SIGHUP, &sa, NULL);
155 		sigaction(SIGINT, &sa, NULL);
156 		sigaction(SIGTERM, &sa, NULL);
157 	}
158 
159 	lineno = 0;
160 	nfiles = 0;
161 	truncofs = 0;
162 	overfile = NULL;
163 
164 	/* Ensure 10^sufflen < LONG_MAX. */
165 	for (maxfiles = 1, i = 0; i < sufflen; i++) {
166 		if (maxfiles > LONG_MAX / 10)
167 			errx(1, "%ld: suffix too long (limit %ld)",
168 			    sufflen, i);
169 		maxfiles *= 10;
170 	}
171 
172 	/* Create files based on supplied patterns. */
173 	while (nfiles < maxfiles - 1 && (expr = *argv++) != NULL) {
174 		/* Look ahead & see if this pattern has any repetitions. */
175 		if (*argv != NULL && **argv == '{') {
176 			errno = 0;
177 			reps = strtol(*argv + 1, &ep, 10);
178 			if (reps < 0 || *ep != '}' || errno != 0)
179 				errx(1, "%s: bad repetition count", *argv + 1);
180 			argv++;
181 		} else
182 			reps = 0;
183 
184 		if (*expr == '/' || *expr == '%') {
185 			do
186 				do_rexp(expr);
187 			while (reps-- != 0 && nfiles < maxfiles - 1);
188 		} else if (isdigit((unsigned char)*expr))
189 			do_lineno(expr);
190 		else
191 			errx(1, "%s: unrecognised pattern", expr);
192 	}
193 
194 	/* Copy the rest into a new file. */
195 	if (!feof(infile)) {
196 		ofp = newfile();
197 		while ((p = get_line()) != NULL && fputs(p, ofp) == 0)
198 			;
199 		if (!sflag)
200 			printf("%jd\n", (intmax_t)ftello(ofp));
201 		if (fclose(ofp) != 0)
202 			err(1, "%s", currfile);
203 	}
204 
205 	toomuch(NULL, 0);
206 	doclean = 0;
207 
208 	return (0);
209 }
210 
211 static void
usage(void)212 usage(void)
213 {
214 
215 	fprintf(stderr,
216 "usage: csplit [-ks] [-f prefix] [-n number] file args ...\n");
217 	exit(1);
218 }
219 
220 static void
handlesig(int sig __unused)221 handlesig(int sig __unused)
222 {
223 	const char msg[] = "csplit: caught signal, cleaning up\n";
224 
225 	write(STDERR_FILENO, msg, sizeof(msg) - 1);
226 	cleanup();
227 	_exit(2);
228 }
229 
230 /* Create a new output file. */
231 static FILE *
newfile(void)232 newfile(void)
233 {
234 	FILE *fp;
235 
236 	if ((size_t)snprintf(currfile, sizeof(currfile), "%s%0*ld", prefix,
237 	    (int)sufflen, nfiles) >= sizeof(currfile))
238 		errc(1, ENAMETOOLONG, NULL);
239 	if ((fp = fopen(currfile, "w+")) == NULL)
240 		err(1, "%s", currfile);
241 	nfiles++;
242 
243 	return (fp);
244 }
245 
246 /* Remove partial output, called before exiting. */
247 static void
cleanup(void)248 cleanup(void)
249 {
250 	char fnbuf[PATH_MAX];
251 	long i;
252 
253 	if (!doclean)
254 		return;
255 
256 	/*
257 	 * NOTE: One cannot portably assume to be able to call snprintf()
258 	 * from inside a signal handler. It does, however, appear to be safe
259 	 * to do on FreeBSD. The solution to this problem is worse than the
260 	 * problem itself.
261 	 */
262 
263 	for (i = 0; i < nfiles; i++) {
264 		snprintf(fnbuf, sizeof(fnbuf), "%s%0*ld", prefix,
265 		    (int)sufflen, i);
266 		unlink(fnbuf);
267 	}
268 }
269 
270 /* Read a line from the input into a static buffer. */
271 static char *
get_line(void)272 get_line(void)
273 {
274 	static char lbuf[LINE_MAX];
275 	FILE *src;
276 
277 	src = overfile != NULL ? overfile : infile;
278 
279 again: if (fgets(lbuf, sizeof(lbuf), src) == NULL) {
280 		if (src == overfile) {
281 			src = infile;
282 			goto again;
283 		}
284 		return (NULL);
285 	}
286 	if (ferror(src))
287 		err(1, "%s", infn);
288 	lineno++;
289 
290 	return (lbuf);
291 }
292 
293 /* Conceptually rewind the input (as obtained by get_line()) back `n' lines. */
294 static void
toomuch(FILE * ofp,long n)295 toomuch(FILE *ofp, long n)
296 {
297 	char buf[BUFSIZ];
298 	size_t i, nread;
299 
300 	if (overfile != NULL) {
301 		/*
302 		 * Truncate the previous file we overflowed into back to
303 		 * the correct length, close it.
304 		 */
305 		if (fflush(overfile) != 0)
306 			err(1, "overflow");
307 		if (ftruncate(fileno(overfile), truncofs) != 0)
308 			err(1, "overflow");
309 		if (fclose(overfile) != 0)
310 			err(1, "overflow");
311 		overfile = NULL;
312 	}
313 
314 	if (n == 0)
315 		/* Just tidying up */
316 		return;
317 
318 	lineno -= n;
319 
320 	/*
321 	 * Wind the overflow file backwards to `n' lines before the
322 	 * current one.
323 	 */
324 	do {
325 		if (ftello(ofp) < (off_t)sizeof(buf))
326 			rewind(ofp);
327 		else
328 			fseeko(ofp, -(off_t)sizeof(buf), SEEK_CUR);
329 		if (ferror(ofp))
330 			errx(1, "%s: can't seek", currfile);
331 		if ((nread = fread(buf, 1, sizeof(buf), ofp)) == 0)
332 			errx(1, "can't read overflowed output");
333 		if (fseeko(ofp, -(off_t)nread, SEEK_CUR) != 0)
334 			err(1, "%s", currfile);
335 		for (i = 1; i <= nread; i++)
336 			if (buf[nread - i] == '\n' && n-- == 0)
337 				break;
338 		if (ftello(ofp) == 0)
339 			break;
340 	} while (n > 0);
341 	if (fseeko(ofp, nread - i + 1, SEEK_CUR) != 0)
342 		err(1, "%s", currfile);
343 
344 	/*
345 	 * get_line() will read from here. Next call will truncate to
346 	 * truncofs in this file.
347 	 */
348 	overfile = ofp;
349 	truncofs = ftello(overfile);
350 }
351 
352 /* Handle splits for /regexp/ and %regexp% patterns. */
353 static void
do_rexp(const char * expr)354 do_rexp(const char *expr)
355 {
356 	regex_t cre;
357 	intmax_t nwritten;
358 	long ofs;
359 	int first;
360 	char *ecopy, *ep, *p, *pofs, *re;
361 	FILE *ofp;
362 
363 	if ((ecopy = strdup(expr)) == NULL)
364 		err(1, "strdup");
365 
366 	re = ecopy + 1;
367 	if ((pofs = strrchr(ecopy, *expr)) == NULL || pofs[-1] == '\\')
368 		errx(1, "%s: missing trailing %c", expr, *expr);
369 	*pofs++ = '\0';
370 
371 	if (*pofs != '\0') {
372 		errno = 0;
373 		ofs = strtol(pofs, &ep, 10);
374 		if (*ep != '\0' || errno != 0)
375 			errx(1, "%s: bad offset", pofs);
376 	} else
377 		ofs = 0;
378 
379 	if (regcomp(&cre, re, REG_BASIC|REG_NOSUB) != 0)
380 		errx(1, "%s: bad regular expression", re);
381 
382 	if (*expr == '/')
383 		/* /regexp/: Save results to a file. */
384 		ofp = newfile();
385 	else {
386 		/* %regexp%: Make a temporary file for overflow. */
387 		if ((ofp = tmpfile()) == NULL)
388 			err(1, "tmpfile");
389 	}
390 
391 	/* Read and output lines until we get a match. */
392 	first = 1;
393 	while ((p = get_line()) != NULL) {
394 		if (fputs(p, ofp) != 0)
395 			break;
396 		if (!first && regexec(&cre, p, 0, NULL, 0) == 0)
397 			break;
398 		first = 0;
399 	}
400 
401 	if (p == NULL)
402 		errx(1, "%s: no match", re);
403 
404 	if (ofs <= 0) {
405 		/*
406 		 * Negative (or zero) offset: throw back any lines we should
407 		 * not have read yet.
408 		  */
409 		if (p != NULL) {
410 			toomuch(ofp, -ofs + 1);
411 			nwritten = (intmax_t)truncofs;
412 		} else
413 			nwritten = (intmax_t)ftello(ofp);
414 	} else {
415 		/*
416 		 * Positive offset: copy the requested number of lines
417 		 * after the match.
418 		 */
419 		while (--ofs > 0 && (p = get_line()) != NULL)
420 			fputs(p, ofp);
421 		toomuch(NULL, 0);
422 		nwritten = (intmax_t)ftello(ofp);
423 		if (fclose(ofp) != 0)
424 			err(1, "%s", currfile);
425 	}
426 
427 	if (!sflag && *expr == '/')
428 		printf("%jd\n", nwritten);
429 
430 	regfree(&cre);
431 	free(ecopy);
432 }
433 
434 /* Handle splits based on line number. */
435 static void
do_lineno(const char * expr)436 do_lineno(const char *expr)
437 {
438 	long lastline, tgtline;
439 	char *ep, *p;
440 	FILE *ofp;
441 
442 	errno = 0;
443 	tgtline = strtol(expr, &ep, 10);
444 	if (tgtline <= 0 || errno != 0 || *ep != '\0')
445 		errx(1, "%s: bad line number", expr);
446 	lastline = tgtline;
447 	if (lastline <= lineno)
448 		errx(1, "%s: can't go backwards", expr);
449 
450 	while (nfiles < maxfiles - 1) {
451 		ofp = newfile();
452 		while (lineno + 1 != lastline) {
453 			if ((p = get_line()) == NULL)
454 				errx(1, "%ld: out of range", lastline);
455 			if (fputs(p, ofp) != 0)
456 				break;
457 		}
458 		if (!sflag)
459 			printf("%jd\n", (intmax_t)ftello(ofp));
460 		if (fclose(ofp) != 0)
461 			err(1, "%s", currfile);
462 		if (reps-- == 0)
463 			break;
464 		lastline += tgtline;
465 	}
466 }
467