xref: /dragonfly/usr.bin/csplit/csplit.c (revision cd1c6085) 
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  * $DragonFly: src/usr.bin/csplit/csplit.c,v 1.1 2004/06/19 21:51:54 hmp Exp $
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/types.h>
49 
50 #include <ctype.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <limits.h>
54 #include <locale.h>
55 #include <regex.h>
56 #include <signal.h>
57 #include <stdint.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62 
63 void	 cleanup(void);
64 void	 do_lineno(const char *);
65 void	 do_rexp(const char *);
66 char	*getline(void);
67 void	 handlesig(int);
68 FILE	*newfile(void);
69 void	 toomuch(FILE *, long);
70 void	 usage(void);
71 
72 /*
73  * Command line options
74  */
75 const char *prefix;		/* File name prefix */
76 long	 sufflen;		/* Number of decimal digits for suffix */
77 int	 sflag;			/* Suppress output of file names */
78 int	 kflag;			/* Keep output if error occurs */
79 
80 /*
81  * Other miscellaneous globals (XXX too many)
82  */
83 long	 lineno;		/* Current line number in input file */
84 long	 reps;			/* Number of repetitions for this pattern */
85 long	 nfiles;		/* Number of files output so far */
86 long	 maxfiles;		/* Maximum number of files we can create */
87 char	 currfile[PATH_MAX];	/* Current output file */
88 const char *infn;		/* Name of the input file */
89 FILE	*infile;		/* Input file handle */
90 FILE	*overfile;		/* Overflow file for toomuch() */
91 off_t	 truncofs;		/* Offset this file should be truncated at */
92 int	 doclean;		/* Should cleanup() remove output? */
93 
94 int
95 main(int argc, char *argv[])
96 {
97 	struct sigaction sa;
98 	long i;
99 	int ch;
100 	const char *expr;
101 	char *ep, *p;
102 	FILE *ofp;
103 
104 	setlocale(LC_ALL, "");
105 
106 	kflag = sflag = 0;
107 	prefix = "xx";
108 	sufflen = 2;
109 	while ((ch = getopt(argc, argv, "ksf:n:")) > 0) {
110 		switch (ch) {
111 		case 'f':
112 			prefix = optarg;
113 			break;
114 		case 'k':
115 			kflag = 1;
116 			break;
117 		case 'n':
118 			errno = 0;
119 			sufflen = strtol(optarg, &ep, 10);
120 			if (sufflen <= 0 || *ep != '\0' || errno != 0)
121 				errx(1, "%s: bad suffix length", optarg);
122 			break;
123 		case 's':
124 			sflag = 1;
125 			break;
126 		default:
127 			usage();
128 			/*NOTREACHED*/
129 		}
130 	}
131 
132 	if (sufflen + strlen(prefix) >= PATH_MAX)
133 		errx(1, "name too long");
134 
135 	argc -= optind;
136 	argv += optind;
137 
138 	if ((infn = *argv++) == NULL)
139 		usage();
140 	if (strcmp(infn, "-") == 0) {
141 		infile = stdin;
142 		infn = "stdin";
143 	} else if ((infile = fopen(infn, "r")) == NULL)
144 		err(1, "%s", infn);
145 
146 	if (!kflag) {
147 		doclean = 1;
148 		atexit(cleanup);
149 		sa.sa_flags = 0;
150 		sa.sa_handler = handlesig;
151 		sigemptyset(&sa.sa_mask);
152 		sigaddset(&sa.sa_mask, SIGHUP);
153 		sigaddset(&sa.sa_mask, SIGINT);
154 		sigaddset(&sa.sa_mask, SIGTERM);
155 		sigaction(SIGHUP, &sa, NULL);
156 		sigaction(SIGINT, &sa, NULL);
157 		sigaction(SIGTERM, &sa, NULL);
158 	}
159 
160 	lineno = 0;
161 	nfiles = 0;
162 	truncofs = 0;
163 	overfile = NULL;
164 
165 	/* Ensure 10^sufflen < LONG_MAX. */
166 	for (maxfiles = 1, i = 0; i < sufflen; i++) {
167 		if (maxfiles > LONG_MAX / 10)
168 			errx(1, "%ld: suffix too long (limit %ld)",
169 			    sufflen, i);
170 		maxfiles *= 10;
171 	}
172 
173 	/* Create files based on supplied patterns. */
174 	while (nfiles < maxfiles - 1 && (expr = *argv++) != NULL) {
175 		/* Look ahead & see if this pattern has any repetitions. */
176 		if (*argv != NULL && **argv == '{') {
177 			errno = 0;
178 			reps = strtol(*argv + 1, &ep, 10);
179 			if (reps < 0 || *ep != '}' || errno != 0)
180 				errx(1, "%s: bad repetition count", *argv + 1);
181 			argv++;
182 		} else
183 			reps = 0;
184 
185 		if (*expr == '/' || *expr == '%') {
186 			do
187 				do_rexp(expr);
188 			while (reps-- != 0 && nfiles < maxfiles - 1);
189 		} else if (isdigit((unsigned char)*expr))
190 			do_lineno(expr);
191 		else
192 			errx(1, "%s: unrecognised pattern", expr);
193 	}
194 
195 	/* Copy the rest into a new file. */
196 	if (!feof(infile)) {
197 		ofp = newfile();
198 		while ((p = getline()) != NULL && fputs(p, ofp) == 0)
199 			;
200 		if (!sflag)
201 			printf("%jd\n", (intmax_t)ftello(ofp));
202 		if (fclose(ofp) != 0)
203 			err(1, "%s", currfile);
204 	}
205 
206 	toomuch(NULL, 0);
207 	doclean = 0;
208 
209 	return (0);
210 }
211 
212 void
213 usage(void)
214 {
215 
216 	fprintf(stderr,
217 "usage: csplit [-ks] [-f prefix] [-n number] file args ...\n");
218 	exit(1);
219 }
220 
221 void
222 handlesig(int sig __unused)
223 {
224 	const char msg[] = "csplit: caught signal, cleaning up\n";
225 
226 	write(STDERR_FILENO, msg, sizeof(msg) - 1);
227 	cleanup();
228 	_exit(2);
229 }
230 
231 /* Create a new output file. */
232 FILE *
233 newfile(void)
234 {
235 	FILE *fp;
236 
237 	if ((size_t)snprintf(currfile, sizeof(currfile), "%s%0*ld", prefix,
238 	    (int)sufflen, nfiles) >= sizeof(currfile))
239 		errc(1, ENAMETOOLONG, NULL);
240 	if ((fp = fopen(currfile, "w+")) == NULL)
241 		err(1, "%s", currfile);
242 	nfiles++;
243 
244 	return (fp);
245 }
246 
247 /* Remove partial output, called before exiting. */
248 void
249 cleanup(void)
250 {
251 	char fnbuf[PATH_MAX];
252 	long i;
253 
254 	if (!doclean)
255 		return;
256 
257 	/*
258 	 * NOTE: One cannot portably assume to be able to call snprintf()
259 	 * from inside a signal handler. It does, however, appear to be safe
260 	 * to do on FreeBSD. The solution to this problem is worse than the
261 	 * problem itself.
262 	 */
263 
264 	for (i = 0; i < nfiles; i++) {
265 		snprintf(fnbuf, sizeof(fnbuf), "%s%0*ld", prefix,
266 		    (int)sufflen, i);
267 		unlink(fnbuf);
268 	}
269 }
270 
271 /* Read a line from the input into a static buffer. */
272 char *
273 getline(void)
274 {
275 	static char lbuf[LINE_MAX];
276 	FILE *src;
277 
278 	src = overfile != NULL ? overfile : infile;
279 
280 again: if (fgets(lbuf, sizeof(lbuf), src) == NULL) {
281 		if (src == overfile) {
282 			src = infile;
283 			goto again;
284 		}
285 		return (NULL);
286 	}
287 	if (ferror(src))
288 		err(1, "%s", infn);
289 	lineno++;
290 
291 	return (lbuf);
292 }
293 
294 /* Conceptually rewind the input (as obtained by getline()) back `n' lines. */
295 void
296 toomuch(FILE *ofp, long n)
297 {
298 	char buf[BUFSIZ];
299 	size_t i, nread;
300 
301 	if (overfile != NULL) {
302 		/*
303 		 * Truncate the previous file we overflowed into back to
304 		 * the correct length, close it.
305 		 */
306 		if (fflush(overfile) != 0)
307 			err(1, "overflow");
308 		if (ftruncate(fileno(overfile), truncofs) != 0)
309 			err(1, "overflow");
310 		if (fclose(overfile) != 0)
311 			err(1, "overflow");
312 		overfile = NULL;
313 	}
314 
315 	if (n == 0)
316 		/* Just tidying up */
317 		return;
318 
319 	lineno -= n;
320 
321 	/*
322 	 * Wind the overflow file backwards to `n' lines before the
323 	 * current one.
324 	 */
325 	do {
326 		if (ftello(ofp) < (off_t)sizeof(buf))
327 			rewind(ofp);
328 		else
329 			fseeko(ofp, -(off_t)sizeof(buf), SEEK_CUR);
330 		if (ferror(ofp))
331 			errx(1, "%s: can't seek", currfile);
332 		if ((nread = fread(buf, 1, sizeof(buf), ofp)) == 0)
333 			errx(1, "can't read overflowed output");
334 		if (fseeko(ofp, -(off_t)nread, SEEK_CUR) != 0)
335 			err(1, "%s", currfile);
336 		for (i = 1; i <= nread; i++)
337 			if (buf[nread - i] == '\n' && n-- == 0)
338 				break;
339 		if (ftello(ofp) == 0)
340 			break;
341 	} while (n > 0);
342 	if (fseeko(ofp, nread - i + 1, SEEK_CUR) != 0)
343 		err(1, "%s", currfile);
344 
345 	/*
346 	 * getline() will read from here. Next call will truncate to
347 	 * truncofs in this file.
348 	 */
349 	overfile = ofp;
350 	truncofs = ftello(overfile);
351 }
352 
353 /* Handle splits for /regexp/ and %regexp% patterns. */
354 void
355 do_rexp(const char *expr)
356 {
357 	regex_t cre;
358 	intmax_t nwritten;
359 	long ofs;
360 	int first;
361 	char *ecopy, *ep, *p, *pofs, *re;
362 	FILE *ofp;
363 
364 	if ((ecopy = strdup(expr)) == NULL)
365 		err(1, "strdup");
366 
367 	re = ecopy + 1;
368 	if ((pofs = strrchr(ecopy, *expr)) == NULL || pofs[-1] == '\\')
369 		errx(1, "%s: missing trailing %c", expr, *expr);
370 	*pofs++ = '\0';
371 
372 	if (*pofs != '\0') {
373 		errno = 0;
374 		ofs = strtol(pofs, &ep, 10);
375 		if (*ep != '\0' || errno != 0)
376 			errx(1, "%s: bad offset", pofs);
377 	} else
378 		ofs = 0;
379 
380 	if (regcomp(&cre, re, REG_BASIC|REG_NOSUB) != 0)
381 		errx(1, "%s: bad regular expression", re);
382 
383 	if (*expr == '/')
384 		/* /regexp/: Save results to a file. */
385 		ofp = newfile();
386 	else {
387 		/* %regexp%: Make a temporary file for overflow. */
388 		if ((ofp = tmpfile()) == NULL)
389 			err(1, "tmpfile");
390 	}
391 
392 	/* Read and output lines until we get a match. */
393 	first = 1;
394 	while ((p = getline()) != NULL) {
395 		if (fputs(p, ofp) != 0)
396 			break;
397 		if (!first && regexec(&cre, p, 0, NULL, 0) == 0)
398 			break;
399 		first = 0;
400 	}
401 
402 	if (p == NULL)
403 		errx(1, "%s: no match", re);
404 
405 	if (ofs <= 0) {
406 		/*
407 		 * Negative (or zero) offset: throw back any lines we should
408 		 * not have read yet.
409 		  */
410 		if (p != NULL) {
411 			toomuch(ofp, -ofs + 1);
412 			nwritten = (intmax_t)truncofs;
413 		} else
414 			nwritten = (intmax_t)ftello(ofp);
415 	} else {
416 		/*
417 		 * Positive offset: copy the requested number of lines
418 		 * after the match.
419 		 */
420 		while (--ofs > 0 && (p = getline()) != NULL)
421 			fputs(p, ofp);
422 		toomuch(NULL, 0);
423 		nwritten = (intmax_t)ftello(ofp);
424 		if (fclose(ofp) != 0)
425 			err(1, "%s", currfile);
426 	}
427 
428 	if (!sflag && *expr == '/')
429 		printf("%jd\n", nwritten);
430 
431 	regfree(&cre);
432 	free(ecopy);
433 }
434 
435 /* Handle splits based on line number. */
436 void
437 do_lineno(const char *expr)
438 {
439 	long lastline, tgtline;
440 	char *ep, *p;
441 	FILE *ofp;
442 
443 	errno = 0;
444 	tgtline = strtol(expr, &ep, 10);
445 	if (tgtline <= 0 || errno != 0 || *ep != '\0')
446 		errx(1, "%s: bad line number", expr);
447 	lastline = tgtline;
448 	if (lastline <= lineno)
449 		errx(1, "%s: can't go backwards", expr);
450 
451 	while (nfiles < maxfiles - 1) {
452 		ofp = newfile();
453 		while (lineno + 1 != lastline) {
454 			if ((p = getline()) == NULL)
455 				errx(1, "%ld: out of range", lastline);
456 			if (fputs(p, ofp) != 0)
457 				break;
458 		}
459 		if (!sflag)
460 			printf("%jd\n", (intmax_t)ftello(ofp));
461 		if (fclose(ofp) != 0)
462 			err(1, "%s", currfile);
463 		if (reps-- == 0)
464 			break;
465 		lastline += tgtline;
466 	}
467 }
468