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  * $DragonFly: src/usr.bin/csplit/csplit.c,v 1.1 2004/06/19 21:51:54 hmp Exp $
  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 <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 void     cleanup(void);
  64 void     do_lineno(const char *);
  65 void     do_rexp(const char *);
  66 char    *getline(void);
  67 void     handlesig(int);
  68 FILE    *newfile(void);
  69 void     toomuch(FILE *, long);
  70 void     usage(void);
  71
  72 /*
  73  * Command line options
  74  */
  75 const char *prefix;             /* File name prefix */
  76 long     sufflen;               /* Number of decimal digits for suffix */
  77 int      sflag;                 /* Suppress output of file names */
  78 int      kflag;                 /* Keep output if error occurs */
  79
  80 /*
  81  * Other miscellaneous globals (XXX too many)
  82  */
  83 long     lineno;                /* Current line number in input file */
  84 long     reps;                  /* Number of repetitions for this pattern */
  85 long     nfiles;                /* Number of files output so far */
  86 long     maxfiles;              /* Maximum number of files we can create */
  87 char     currfile[PATH_MAX];    /* Current output file */
  88 const char *infn;               /* Name of the input file */
  89 FILE    *infile;                /* Input file handle */
  90 FILE    *overfile;              /* Overflow file for toomuch() */
  91 off_t    truncofs;              /* Offset this file should be truncated at */
  92 int      doclean;               /* Should cleanup() remove output? */
  93
  94 int
  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 = getline()) != NULL && fputs(p, ofp) == 0)
 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 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 void
 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 FILE *
 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 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 char *
 273 getline(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 getline()) back `n' lines. */
 295 void
 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          * getline() 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 void
 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 = getline()) != NULL) {
 395                 if (fputs(p, ofp) != 0)
 396                         break;
 397                 if (!first && regexec(&cre, p, 0, NULL, 0) == 0)
 398                         break;
 399                 first = 0;
 400         }
 401
 402         if (p == NULL)
 403                 errx(1, "%s: no match", re);
 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 = getline()) != 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
 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 = getline()) == 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 }