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