1 /* $OpenBSD: csplit.c,v 1.12 2023/03/08 04:43:10 guenther 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/types.h>
49
50 #include <ctype.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <limits.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 void cleanup(void);
63 void do_lineno(const char *);
64 void do_rexp(const char *);
65 char *get_line(void);
66 void handlesig(int);
67 FILE *newfile(void);
68 void toomuch(FILE *, long);
69 static void __dead usage(void);
70
71 /*
72 * Command line options
73 */
74 const char *prefix; /* File name prefix */
75 long sufflen; /* Number of decimal digits for suffix */
76 int sflag; /* Suppress output of file names */
77 int kflag; /* Keep output if error occurs */
78
79 /*
80 * Other miscellaneous globals (XXX too many)
81 */
82 long lineno; /* Current line number in input file */
83 long reps; /* Number of repetitions for this pattern */
84 long nfiles; /* Number of files output so far */
85 long maxfiles; /* Maximum number of files we can create */
86 char currfile[PATH_MAX]; /* Current output file */
87 const char *infn; /* Name of the input file */
88 FILE *infile; /* Input file handle */
89 FILE *overfile; /* Overflow file for toomuch() */
90 off_t truncofs; /* Offset this file should be truncated at */
91 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 if (pledge("stdio rpath wpath cpath", NULL) == -1)
104 err(1, "pledge");
105
106 kflag = sflag = 0;
107 prefix = "xx";
108 sufflen = 2;
109 while ((ch = getopt(argc, argv, "f:kn:s")) != -1) {
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 }
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 __dead
usage(void)212 usage(void)
213 {
214 extern char *__progname;
215
216 fprintf(stderr,
217 "usage: %s [-ks] [-f prefix] [-n number] file arg ...\n",
218 __progname);
219 exit(1);
220 }
221
222 void
handlesig(int sig)223 handlesig(int sig)
224 {
225 const char msg[] = "csplit: caught signal, cleaning up\n";
226
227 write(STDERR_FILENO, msg, sizeof(msg) - 1);
228 cleanup();
229 _exit(2);
230 }
231
232 /* Create a new output file. */
233 FILE *
newfile(void)234 newfile(void)
235 {
236 FILE *fp;
237
238 if ((size_t)snprintf(currfile, sizeof(currfile), "%s%0*ld", prefix,
239 (int)sufflen, nfiles) >= sizeof(currfile))
240 errc(1, ENAMETOOLONG, "%s", currfile);
241 if ((fp = fopen(currfile, "w+")) == NULL)
242 err(1, "%s", currfile);
243 nfiles++;
244
245 return (fp);
246 }
247
248 /* Remove partial output, called before exiting. */
249 void
cleanup(void)250 cleanup(void)
251 {
252 char fnbuf[PATH_MAX];
253 long i;
254
255 if (!doclean)
256 return;
257
258 /*
259 * NOTE: One cannot portably assume to be able to call snprintf() from
260 * inside a signal handler. It is, however, safe to do on OpenBSD.
261 */
262 for (i = 0; i < nfiles; i++) {
263 snprintf(fnbuf, sizeof(fnbuf), "%s%0*ld", prefix,
264 (int)sufflen, i);
265 unlink(fnbuf);
266 }
267 }
268
269 /* Read a line from the input into a static buffer. */
270 char *
get_line(void)271 get_line(void)
272 {
273 static char lbuf[LINE_MAX];
274 FILE *src;
275
276 src = overfile != NULL ? overfile : infile;
277
278 again: if (fgets(lbuf, sizeof(lbuf), src) == NULL) {
279 if (src == overfile) {
280 src = infile;
281 goto again;
282 }
283 return (NULL);
284 }
285 if (ferror(src))
286 err(1, "%s", infn);
287 lineno++;
288
289 return (lbuf);
290 }
291
292 /* Conceptually rewind the input (as obtained by get_line()) back `n' lines. */
293 void
toomuch(FILE * ofp,long n)294 toomuch(FILE *ofp, long n)
295 {
296 char buf[BUFSIZ];
297 size_t i, nread;
298
299 if (overfile != NULL) {
300 /*
301 * Truncate the previous file we overflowed into back to
302 * the correct length, close it.
303 */
304 if (fflush(overfile) != 0)
305 err(1, "overflow");
306 if (ftruncate(fileno(overfile), truncofs) != 0)
307 err(1, "overflow");
308 if (fclose(overfile) != 0)
309 err(1, "overflow");
310 overfile = NULL;
311 }
312
313 if (n == 0)
314 /* Just tidying up */
315 return;
316
317 lineno -= n;
318
319 /*
320 * Wind the overflow file backwards to `n' lines before the
321 * current one.
322 */
323 do {
324 if (ftello(ofp) < (off_t)sizeof(buf))
325 rewind(ofp);
326 else
327 fseeko(ofp, -(off_t)sizeof(buf), SEEK_CUR);
328 if (ferror(ofp))
329 errx(1, "%s: can't seek", currfile);
330 if ((nread = fread(buf, 1, sizeof(buf), ofp)) == 0)
331 errx(1, "can't read overflowed output");
332 if (fseeko(ofp, -(off_t)nread, SEEK_CUR) != 0)
333 err(1, "%s", currfile);
334 for (i = 1; i <= nread; i++)
335 if (buf[nread - i] == '\n' && n-- == 0)
336 break;
337 if (ftello(ofp) == 0)
338 break;
339 } while (n > 0);
340 if (fseeko(ofp, (off_t)(nread - i + 1), SEEK_CUR) != 0)
341 err(1, "%s", currfile);
342
343 /*
344 * get_line() will read from here. Next call will truncate to
345 * truncofs in this file.
346 */
347 overfile = ofp;
348 truncofs = ftello(overfile);
349 }
350
351 /* Handle splits for /regexp/ and %regexp% patterns. */
352 void
do_rexp(const char * expr)353 do_rexp(const char *expr)
354 {
355 regex_t cre;
356 intmax_t nwritten;
357 long ofs;
358 int first;
359 char *ecopy, *ep, *p, *pofs, *re;
360 FILE *ofp;
361
362 if ((ecopy = strdup(expr)) == NULL)
363 err(1, "strdup");
364
365 re = ecopy + 1;
366 if ((pofs = strrchr(ecopy, *expr)) == NULL || pofs[-1] == '\\')
367 errx(1, "%s: missing trailing %c", expr, *expr);
368 *pofs++ = '\0';
369
370 if (*pofs != '\0') {
371 errno = 0;
372 ofs = strtol(pofs, &ep, 10);
373 if (*ep != '\0' || errno != 0)
374 errx(1, "%s: bad offset", pofs);
375 } else
376 ofs = 0;
377
378 if (regcomp(&cre, re, REG_BASIC|REG_NOSUB) != 0)
379 errx(1, "%s: bad regular expression", re);
380
381 if (*expr == '/')
382 /* /regexp/: Save results to a file. */
383 ofp = newfile();
384 else {
385 /* %regexp%: Make a temporary file for overflow. */
386 if ((ofp = tmpfile()) == NULL)
387 err(1, "tmpfile");
388 }
389
390 /* Read and output lines until we get a match. */
391 first = 1;
392 while ((p = get_line()) != NULL) {
393 if (fputs(p, ofp) != 0)
394 break;
395 if (!first && regexec(&cre, p, 0, NULL, 0) == 0)
396 break;
397 first = 0;
398 }
399
400 if (p == NULL) {
401 toomuch(NULL, 0);
402 errx(1, "%s: no match", re);
403 }
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 = get_line()) != 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
do_lineno(const char * expr)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 = get_line()) == 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