csplit.c revision 97977
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 27/* 28 * csplit -- split files based on context 29 * 30 * This utility splits its input into numbered output files by line number 31 * or by a regular expression. Regular expression matches have an optional 32 * offset with them, allowing the split to occur a specified number of 33 * lines before or after the match. 34 * 35 * To handle negative offsets, we stop reading when the match occurs and 36 * store the offset that the file should have been split at, then use 37 * this output file as input until all the "overflowed" lines have been read. 38 * The file is then closed and truncated to the correct length. 39 * 40 * We assume that the output files can be seeked upon (ie. they cannot be 41 * symlinks to named pipes or character devices), but make no such 42 * assumption about the input. 43 */ 44 45#include <sys/cdefs.h> 46__FBSDID("$FreeBSD: head/usr.bin/csplit/csplit.c 97977 2002-06-07 01:04:24Z tjr $"); 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 63void cleanup(void); 64void do_lineno(const char *); 65void do_rexp(const char *); 66char *getline(void); 67void handlesig(int); 68FILE *newfile(void); 69void toomuch(FILE *, long); 70void usage(void); 71 72/* 73 * Command line options 74 */ 75const char *prefix; /* File name prefix */ 76long sufflen; /* Number of decimal digits for suffix */ 77int sflag; /* Suppress output of file names */ 78int kflag; /* Keep output if error occurs */ 79 80/* 81 * Other miscellaneous globals (XXX too many) 82 */ 83long lineno; /* Current line number in input file */ 84long reps; /* Number of repetitions for this pattern */ 85long nfiles; /* Number of files output so far */ 86long maxfiles; /* Maximum number of files we can create */ 87char currfile[PATH_MAX]; /* Current output file */ 88const char *infn; /* Name of the input file */ 89FILE *infile; /* Input file handle */ 90FILE *overfile; /* Overflow file for toomuch() */ 91off_t truncofs; /* Offset this file should be truncated at */ 92int doclean; /* Should cleanup() remove output? */ 93 94int 95main(int argc, char *argv[]) 96{ 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 signal(SIGHUP, handlesig); 149 signal(SIGINT, handlesig); 150 signal(SIGTERM, handlesig); 151 } 152 153 lineno = 0; 154 nfiles = 0; 155 truncofs = 0; 156 overfile = NULL; 157 158 /* Ensure 10^sufflen < LONG_MAX. */ 159 for (maxfiles = 1, i = 0; i < sufflen; i++) { 160 if (maxfiles > LONG_MAX / 10) 161 errx(1, "%ld: suffix too long (limit %ld)", 162 sufflen, i); 163 maxfiles *= 10; 164 } 165 166 /* Create files based on supplied patterns. */ 167 while (nfiles < maxfiles - 1 && (expr = *argv++) != NULL) { 168 /* Look ahead & see if this pattern has any repetitions. */ 169 if (*argv != NULL && **argv == '{') { 170 errno = 0; 171 reps = strtol(*argv + 1, &ep, 10); 172 if (reps < 0 || *ep != '}' || errno != 0) 173 errx(1, "%s: bad repetition count", *argv + 1); 174 argv++; 175 } else 176 reps = 0; 177 178 if (*expr == '/' || *expr == '%') { 179 do 180 do_rexp(expr); 181 while (reps-- != 0 && nfiles < maxfiles - 1); 182 } else if (isdigit((unsigned char)*expr)) 183 do_lineno(expr); 184 else 185 errx(1, "%s: unrecognised pattern", expr); 186 } 187 188 /* Copy the rest into a new file. */ 189 if (!feof(infile)) { 190 ofp = newfile(); 191 while ((p = getline()) != NULL && fputs(p, ofp) == 0) 192 ; 193 if (!sflag) 194 printf("%jd\n", (intmax_t)ftello(ofp)); 195 if (fclose(ofp) != 0) 196 err(1, "%s", currfile); 197 } 198 199 toomuch(NULL, 0); 200 doclean = 0; 201 202 return (0); 203} 204 205void 206usage(void) 207{ 208 209 fprintf(stderr, 210"usage: csplit [-ks] [-f prefix] [-n number] file args ...\n"); 211 exit(1); 212} 213 214void 215handlesig(int sig __unused) 216{ 217 const char msg[] = "csplit: caught signal, cleaning up\n"; 218 219 write(STDERR_FILENO, msg, sizeof(msg) - 1); 220 cleanup(); 221 _exit(2); 222} 223 224/* Create a new output file. */ 225FILE * 226newfile(void) 227{ 228 FILE *fp; 229 230 snprintf(currfile, sizeof(currfile), "%s%0*ld", prefix, (int)sufflen, 231 nfiles); 232 if ((fp = fopen(currfile, "w+")) == NULL) 233 err(1, "%s", currfile); 234 nfiles++; 235 236 return (fp); 237} 238 239/* Remove partial output, called before exiting. */ 240void 241cleanup(void) 242{ 243 char fnbuf[PATH_MAX]; 244 long i; 245 246 if (!doclean) 247 return; 248 249 /* 250 * NOTE: One cannot portably assume to be able to call snprintf() 251 * from inside a signal handler. It does, however, appear to be safe 252 * to do on FreeBSD. The solution to this problem is worse than the 253 * problem itself. 254 */ 255 256 for (i = 0; i < nfiles; i++) { 257 snprintf(fnbuf, sizeof(fnbuf), "%s%0*ld", prefix, 258 (int)sufflen, i); 259 unlink(fnbuf); 260 } 261} 262 263/* Read a line from the input into a static buffer. */ 264char * 265getline(void) 266{ 267 static char lbuf[LINE_MAX]; 268 FILE *src; 269 270 src = overfile != NULL ? overfile : infile; 271 272again: if (fgets(lbuf, sizeof(lbuf), src) == NULL) { 273 if (src == overfile) { 274 src = infile; 275 goto again; 276 } 277 return (NULL); 278 } 279 if (ferror(src)) 280 err(1, "%s", infn); 281 lineno++; 282 283 return (lbuf); 284} 285 286/* Conceptually rewind the input (as obtained by getline()) back `n' lines. */ 287void 288toomuch(FILE *ofp, long n) 289{ 290 char buf[BUFSIZ]; 291 size_t i, nread; 292 293 if (overfile != NULL) { 294 /* 295 * Truncate the previous file we overflowed into back to 296 * the correct length, close it. 297 */ 298 if (fflush(overfile) != 0) 299 err(1, "overflow"); 300 if (ftruncate(fileno(overfile), truncofs) != 0) 301 err(1, "overflow"); 302 if (fclose(overfile) != 0) 303 err(1, "overflow"); 304 overfile = NULL; 305 } 306 307 if (n == 0) 308 /* Just tidying up */ 309 return; 310 311 lineno -= n; 312 313 /* 314 * Wind the overflow file backwards to `n' lines before the 315 * current one. 316 */ 317 do { 318 if (ftello(ofp) < (off_t)sizeof(buf)) 319 rewind(ofp); 320 else 321 fseek(ofp, -(long)sizeof(buf), SEEK_CUR); 322 if (ferror(ofp)) 323 errx(1, "%s: can't seek", currfile); 324 if ((nread = fread(buf, 1, sizeof(buf), ofp)) == 0) 325 errx(1, "can't read overflowed output"); 326 if (fseek(ofp, -(long)nread, SEEK_CUR) != 0) 327 err(1, "%s", currfile); 328 for (i = 1; i <= nread; i++) 329 if (buf[nread - i] == '\n' && n-- == 0) 330 break; 331 if (ftello(ofp) == 0) 332 break; 333 } while (n > 0); 334 if (fseek(ofp, nread - i + 1, SEEK_CUR) != 0) 335 err(1, "%s", currfile); 336 337 /* 338 * getline() will read from here. Next call will truncate to 339 * truncofs in this file. 340 */ 341 overfile = ofp; 342 truncofs = ftello(overfile); 343} 344 345/* Handle splits for /regexp/ and %regexp% patterns. */ 346void 347do_rexp(const char *expr) 348{ 349 regex_t cre; 350 intmax_t nwritten; 351 long ofs; 352 int first; 353 char *ecopy, *ep, *p, *pofs, *re; 354 FILE *ofp; 355 356 if ((ecopy = strdup(expr)) == NULL) 357 err(1, "strdup"); 358 359 re = ecopy + 1; 360 if ((pofs = strrchr(ecopy, *expr)) == NULL || pofs[-1] == '\\') 361 errx(1, "%s: missing trailing %c", expr, *expr); 362 *pofs++ = '\0'; 363 364 if (*pofs != '\0') { 365 errno = 0; 366 ofs = strtol(pofs, &ep, 10); 367 if (*ep != '\0' || errno != 0) 368 errx(1, "%s: bad offset", pofs); 369 } else 370 ofs = 0; 371 372 if (regcomp(&cre, re, REG_BASIC|REG_NOSUB) != 0) 373 errx(1, "%s: bad regular expression", re); 374 375 if (*expr == '/') 376 /* /regexp/: Save results to a file. */ 377 ofp = newfile(); 378 else { 379 /* %regexp%: Make a temporary file for overflow. */ 380 if ((ofp = tmpfile()) == NULL) 381 err(1, "tmpfile"); 382 } 383 384 /* Read and output lines until we get a match. */ 385 first = 1; 386 while ((p = getline()) != NULL) { 387 if (fputs(p, ofp) != 0) 388 break; 389 if (!first && regexec(&cre, p, 0, NULL, 0) == 0) 390 break; 391 first = 0; 392 } 393 394 if (p == NULL) 395 errx(1, "%s: no match", re); 396 397 if (ofs <= 0) { 398 /* 399 * Negative (or zero) offset: throw back any lines we should 400 * not have read yet. 401 */ 402 if (p != NULL) { 403 toomuch(ofp, -ofs + 1); 404 nwritten = (intmax_t)truncofs; 405 } else 406 nwritten = (intmax_t)ftello(ofp); 407 } else { 408 /* 409 * Positive offset: copy the requested number of lines 410 * after the match. 411 */ 412 while (--ofs > 0 && (p = getline()) != NULL) 413 fputs(p, ofp); 414 toomuch(NULL, 0); 415 nwritten = (intmax_t)ftello(ofp); 416 if (fclose(ofp) != 0) 417 err(1, "%s", currfile); 418 } 419 420 if (!sflag && *expr == '/') 421 printf("%jd\n", nwritten); 422 423 regfree(&cre); 424 free(ecopy); 425} 426 427/* Handle splits based on line number. */ 428void 429do_lineno(const char *expr) 430{ 431 long lastline, tgtline; 432 char *ep, *p; 433 FILE *ofp; 434 435 errno = 0; 436 tgtline = strtol(expr, &ep, 10); 437 if (tgtline <= 0 || errno != 0 || *ep != '\0') 438 errx(1, "%s: bad line number", expr); 439 lastline = tgtline; 440 if (lastline <= lineno) 441 errx(1, "%s: can't go backwards", expr); 442 443 while (nfiles < maxfiles - 1) { 444 ofp = newfile(); 445 while (lineno + 1 != lastline) { 446 if ((p = getline()) == NULL) 447 errx(1, "%ld: out of range", lastline); 448 if (fputs(p, ofp) != 0) 449 break; 450 } 451 if (!sflag) 452 printf("%jd\n", (intmax_t)ftello(ofp)); 453 if (fclose(ofp) != 0) 454 err(1, "%s", currfile); 455 if (reps-- == 0) 456 break; 457 lastline += tgtline; 458 } 459} 460