1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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 #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 static void cleanup(void);
64 static void do_lineno(const char *);
65 static void do_rexp(const char *);
66 static char *get_line(void);
67 static void handlesig(int);
68 static FILE *newfile(void);
69 static void toomuch(FILE *, long);
70 static void usage(void);
71
72 /*
73 * Command line options
74 */
75 static const char *prefix; /* File name prefix */
76 static long sufflen; /* Number of decimal digits for suffix */
77 static int sflag; /* Suppress output of file names */
78 static int kflag; /* Keep output if error occurs */
79
80 /*
81 * Other miscellaneous globals (XXX too many)
82 */
83 static long lineno; /* Current line number in input file */
84 static long reps; /* Number of repetitions for this pattern */
85 static long nfiles; /* Number of files output so far */
86 static long maxfiles; /* Maximum number of files we can create */
87 static char currfile[PATH_MAX]; /* Current output file */
88 static const char *infn; /* Name of the input file */
89 static FILE *infile; /* Input file handle */
90 static FILE *overfile; /* Overflow file for toomuch() */
91 static off_t truncofs; /* Offset this file should be truncated at */
92 static int doclean; /* Should cleanup() remove output? */
93
94 int
main(int argc,char * argv[])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 = get_line()) != NULL && fputs(p, ofp) != EOF)
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 static void
usage(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 static void
handlesig(int sig __unused)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 static FILE *
newfile(void)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 static void
cleanup(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 static char *
get_line(void)273 get_line(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 get_line()) back `n' lines. */
295 static void
toomuch(FILE * ofp,long n)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 * get_line() 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 static void
do_rexp(const char * expr)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 = get_line()) != NULL) {
395 if (fputs(p, ofp) == EOF)
396 break;
397 if (!first && regexec(&cre, p, 0, NULL, 0) == 0)
398 break;
399 first = 0;
400 }
401
402 if (p == NULL) {
403 toomuch(NULL, 0);
404 errx(1, "%s: no match", re);
405 }
406
407 if (ofs <= 0) {
408 /*
409 * Negative (or zero) offset: throw back any lines we should
410 * not have read yet.
411 */
412 if (p != NULL) {
413 toomuch(ofp, -ofs + 1);
414 nwritten = (intmax_t)truncofs;
415 } else
416 nwritten = (intmax_t)ftello(ofp);
417 } else {
418 /*
419 * Positive offset: copy the requested number of lines
420 * after the match.
421 */
422 while (--ofs > 0 && (p = get_line()) != NULL)
423 fputs(p, ofp);
424 toomuch(NULL, 0);
425 nwritten = (intmax_t)ftello(ofp);
426 if (fclose(ofp) != 0)
427 err(1, "%s", currfile);
428 }
429
430 if (!sflag && *expr == '/')
431 printf("%jd\n", nwritten);
432
433 regfree(&cre);
434 free(ecopy);
435 }
436
437 /* Handle splits based on line number. */
438 static void
do_lineno(const char * expr)439 do_lineno(const char *expr)
440 {
441 long lastline, tgtline;
442 char *ep, *p;
443 FILE *ofp;
444
445 errno = 0;
446 tgtline = strtol(expr, &ep, 10);
447 if (tgtline <= 0 || errno != 0 || *ep != '\0')
448 errx(1, "%s: bad line number", expr);
449 lastline = tgtline;
450 if (lastline <= lineno)
451 errx(1, "%s: can't go backwards", expr);
452
453 while (nfiles < maxfiles - 1) {
454 ofp = newfile();
455 while (lineno + 1 != lastline) {
456 if ((p = get_line()) == NULL)
457 errx(1, "%ld: out of range", lastline);
458 if (fputs(p, ofp) == EOF)
459 break;
460 }
461 if (!sflag)
462 printf("%jd\n", (intmax_t)ftello(ofp));
463 if (fclose(ofp) != 0)
464 err(1, "%s", currfile);
465 if (reps-- == 0)
466 break;
467 lastline += tgtline;
468 }
469 }
470