usr.bin/csplit/csplit.c

   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  */
  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/types.h>
  48
  49 #include <ctype.h>
  50 #include <err.h>
  51 #include <errno.h>
  52 #include <limits.h>
  53 #include <locale.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 static void      cleanup(void);
  63 static void      do_lineno(const char *);
  64 static void      do_rexp(const char *);
  65 static char     *get_line(void);
  66 static void      handlesig(int) __dead2;
  67 static FILE     *newfile(void);
  68 static void      toomuch(FILE *, long);
  69 static void      usage(void) __dead2;
  70
  71 /*
  72  * Command line options
  73  */
  74 static const char *prefix;      /* File name prefix */
  75 static long      sufflen;       /* Number of decimal digits for suffix */
  76 static int       sflag;         /* Suppress output of file names */
  77 static int       kflag;         /* Keep output if error occurs */
  78
  79 /*
  80  * Other miscellaneous globals (XXX too many)
  81  */
  82 static long      lineno;        /* Current line number in input file */
  83 static long      reps;          /* Number of repetitions for this pattern */
  84 static long      nfiles;        /* Number of files output so far */
  85 static long      maxfiles;      /* Maximum number of files we can create */
  86 static char      currfile[PATH_MAX]; /* Current output file */
  87 static const char *infn;        /* Name of the input file */
  88 static FILE     *infile;        /* Input file handle */
  89 static FILE     *overfile;      /* Overflow file for toomuch() */
  90 static off_t     truncofs;      /* Offset this file should be truncated at */
  91 static int       doclean;       /* Should cleanup() remove output? */
  92
  93 int
  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         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                 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
 212 usage(void)
 213 {
 214
 215         fprintf(stderr,
 216 "usage: csplit [-ks] [-f prefix] [-n number] file args ...\n");
 217         exit(1);
 218 }
 219
 220 static void
 221 handlesig(int sig __unused)
 222 {
 223         const char msg[] = "csplit: caught signal, cleaning up\n";
 224
 225         write(STDERR_FILENO, msg, sizeof(msg) - 1);
 226         cleanup();
 227         _exit(2);
 228 }
 229
 230 /* Create a new output file. */
 231 static FILE *
 232 newfile(void)
 233 {
 234         FILE *fp;
 235
 236         if ((size_t)snprintf(currfile, sizeof(currfile), "%s%0*ld", prefix,
 237             (int)sufflen, nfiles) >= sizeof(currfile))
 238                 errc(1, ENAMETOOLONG, NULL);
 239         if ((fp = fopen(currfile, "w+")) == NULL)
 240                 err(1, "%s", currfile);
 241         nfiles++;
 242
 243         return (fp);
 244 }
 245
 246 /* Remove partial output, called before exiting. */
 247 static void
 248 cleanup(void)
 249 {
 250         char fnbuf[PATH_MAX];
 251         long i;
 252
 253         if (!doclean)
 254                 return;
 255
 256         /*
 257          * NOTE: One cannot portably assume to be able to call snprintf()
 258          * from inside a signal handler. It does, however, appear to be safe
 259          * to do on FreeBSD. The solution to this problem is worse than the
 260          * problem itself.
 261          */
 262
 263         for (i = 0; i < nfiles; i++) {
 264                 snprintf(fnbuf, sizeof(fnbuf), "%s%0*ld", prefix,
 265                     (int)sufflen, i);
 266                 unlink(fnbuf);
 267         }
 268 }
 269
 270 /* Read a line from the input into a static buffer. */
 271 static char *
 272 get_line(void)
 273 {
 274         static char lbuf[LINE_MAX];
 275         FILE *src;
 276
 277         src = overfile != NULL ? overfile : infile;
 278
 279 again: if (fgets(lbuf, sizeof(lbuf), src) == NULL) {
 280                 if (src == overfile) {
 281                         src = infile;
 282                         goto again;
 283                 }
 284                 return (NULL);
 285         }
 286         if (ferror(src))
 287                 err(1, "%s", infn);
 288         lineno++;
 289
 290         return (lbuf);
 291 }
 292
 293 /* Conceptually rewind the input (as obtained by get_line()) back `n' lines. */
 294 static void
 295 toomuch(FILE *ofp, long n)
 296 {
 297         char buf[BUFSIZ];
 298         size_t i, nread;
 299
 300         if (overfile != NULL) {
 301                 /*
 302                  * Truncate the previous file we overflowed into back to
 303                  * the correct length, close it.
 304                  */
 305                 if (fflush(overfile) != 0)
 306                         err(1, "overflow");
 307                 if (ftruncate(fileno(overfile), truncofs) != 0)
 308                         err(1, "overflow");
 309                 if (fclose(overfile) != 0)
 310                         err(1, "overflow");
 311                 overfile = NULL;
 312         }
 313
 314         if (n == 0)
 315                 /* Just tidying up */
 316                 return;
 317
 318         lineno -= n;
 319
 320         /*
 321          * Wind the overflow file backwards to `n' lines before the
 322          * current one.
 323          */
 324         do {
 325                 if (ftello(ofp) < (off_t)sizeof(buf))
 326                         rewind(ofp);
 327                 else
 328                         fseeko(ofp, -(off_t)sizeof(buf), SEEK_CUR);
 329                 if (ferror(ofp))
 330                         errx(1, "%s: can't seek", currfile);
 331                 if ((nread = fread(buf, 1, sizeof(buf), ofp)) == 0)
 332                         errx(1, "can't read overflowed output");
 333                 if (fseeko(ofp, -(off_t)nread, SEEK_CUR) != 0)
 334                         err(1, "%s", currfile);
 335                 for (i = 1; i <= nread; i++)
 336                         if (buf[nread - i] == '\n' && n-- == 0)
 337                                 break;
 338                 if (ftello(ofp) == 0)
 339                         break;
 340         } while (n > 0);
 341         if (fseeko(ofp, nread - i + 1, SEEK_CUR) != 0)
 342                 err(1, "%s", currfile);
 343
 344         /*
 345          * get_line() will read from here. Next call will truncate to
 346          * truncofs in this file.
 347          */
 348         overfile = ofp;
 349         truncofs = ftello(overfile);
 350 }
 351
 352 /* Handle splits for /regexp/ and %regexp% patterns. */
 353 static void
 354 do_rexp(const char *expr)
 355 {
 356         regex_t cre;
 357         intmax_t nwritten;
 358         long ofs;
 359         int first;
 360         char *ecopy, *ep, *p, *pofs, *re;
 361         FILE *ofp;
 362
 363         if ((ecopy = strdup(expr)) == NULL)
 364                 err(1, "strdup");
 365
 366         re = ecopy + 1;
 367         if ((pofs = strrchr(ecopy, *expr)) == NULL || pofs[-1] == '\\')
 368                 errx(1, "%s: missing trailing %c", expr, *expr);
 369         *pofs++ = '\0';
 370
 371         if (*pofs != '\0') {
 372                 errno = 0;
 373                 ofs = strtol(pofs, &ep, 10);
 374                 if (*ep != '\0' || errno != 0)
 375                         errx(1, "%s: bad offset", pofs);
 376         } else
 377                 ofs = 0;
 378
 379         if (regcomp(&cre, re, REG_BASIC|REG_NOSUB) != 0)
 380                 errx(1, "%s: bad regular expression", re);
 381
 382         if (*expr == '/')
 383                 /* /regexp/: Save results to a file. */
 384                 ofp = newfile();
 385         else {
 386                 /* %regexp%: Make a temporary file for overflow. */
 387                 if ((ofp = tmpfile()) == NULL)
 388                         err(1, "tmpfile");
 389         }
 390
 391         /* Read and output lines until we get a match. */
 392         first = 1;
 393         while ((p = get_line()) != NULL) {
 394                 if (fputs(p, ofp) != 0)
 395                         break;
 396                 if (!first && regexec(&cre, p, 0, NULL, 0) == 0)
 397                         break;
 398                 first = 0;
 399         }
 400
 401         if (p == NULL)
 402                 errx(1, "%s: no match", re);
 403
 404         if (ofs <= 0) {
 405                 /*
 406                  * Negative (or zero) offset: throw back any lines we should
 407                  * not have read yet.
 408                   */
 409                 if (p != NULL) {
 410                         toomuch(ofp, -ofs + 1);
 411                         nwritten = (intmax_t)truncofs;
 412                 } else
 413                         nwritten = (intmax_t)ftello(ofp);
 414         } else {
 415                 /*
 416                  * Positive offset: copy the requested number of lines
 417                  * after the match.
 418                  */
 419                 while (--ofs > 0 && (p = get_line()) != NULL)
 420                         fputs(p, ofp);
 421                 toomuch(NULL, 0);
 422                 nwritten = (intmax_t)ftello(ofp);
 423                 if (fclose(ofp) != 0)
 424                         err(1, "%s", currfile);
 425         }
 426
 427         if (!sflag && *expr == '/')
 428                 printf("%jd\n", nwritten);
 429
 430         regfree(&cre);
 431         free(ecopy);
 432 }
 433
 434 /* Handle splits based on line number. */
 435 static void
 436 do_lineno(const char *expr)
 437 {
 438         long lastline, tgtline;
 439         char *ep, *p;
 440         FILE *ofp;
 441
 442         errno = 0;
 443         tgtline = strtol(expr, &ep, 10);
 444         if (tgtline <= 0 || errno != 0 || *ep != '\0')
 445                 errx(1, "%s: bad line number", expr);
 446         lastline = tgtline;
 447         if (lastline <= lineno)
 448                 errx(1, "%s: can't go backwards", expr);
 449
 450         while (nfiles < maxfiles - 1) {
 451                 ofp = newfile();
 452                 while (lineno + 1 != lastline) {
 453                         if ((p = get_line()) == NULL)
 454                                 errx(1, "%ld: out of range", lastline);
 455                         if (fputs(p, ofp) != 0)
 456                                 break;
 457                 }
 458                 if (!sflag)
 459                         printf("%jd\n", (intmax_t)ftello(ofp));
 460                 if (fclose(ofp) != 0)
 461                         err(1, "%s", currfile);
 462                 if (reps-- == 0)
 463                         break;
 464                 lastline += tgtline;
 465         }
 466 }