freebsd-dev/usr.bin/csplit/csplit.c
Conrad Meyer 48b644192d csplit(1): Fix extraneous output in edge case
When the input to csplit contains fewer lines than the number of matches
specified, extra output was mistakenly included in some output files.

Fix the bug and add a simple ATF regression test.

PR:		219024
Submitted by:	J.R. Oldroyd <fbsd at opal.com>
2017-05-08 15:51:29 +00:00

470 lines
11 KiB
C

/*-
* Copyright (c) 2002 Tim J. Robbins.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* csplit -- split files based on context
*
* This utility splits its input into numbered output files by line number
* or by a regular expression. Regular expression matches have an optional
* offset with them, allowing the split to occur a specified number of
* lines before or after the match.
*
* To handle negative offsets, we stop reading when the match occurs and
* store the offset that the file should have been split at, then use
* this output file as input until all the "overflowed" lines have been read.
* The file is then closed and truncated to the correct length.
*
* We assume that the output files can be seeked upon (ie. they cannot be
* symlinks to named pipes or character devices), but make no such
* assumption about the input.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <regex.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static void cleanup(void);
static void do_lineno(const char *);
static void do_rexp(const char *);
static char *get_line(void);
static void handlesig(int);
static FILE *newfile(void);
static void toomuch(FILE *, long);
static void usage(void);
/*
* Command line options
*/
static const char *prefix; /* File name prefix */
static long sufflen; /* Number of decimal digits for suffix */
static int sflag; /* Suppress output of file names */
static int kflag; /* Keep output if error occurs */
/*
* Other miscellaneous globals (XXX too many)
*/
static long lineno; /* Current line number in input file */
static long reps; /* Number of repetitions for this pattern */
static long nfiles; /* Number of files output so far */
static long maxfiles; /* Maximum number of files we can create */
static char currfile[PATH_MAX]; /* Current output file */
static const char *infn; /* Name of the input file */
static FILE *infile; /* Input file handle */
static FILE *overfile; /* Overflow file for toomuch() */
static off_t truncofs; /* Offset this file should be truncated at */
static int doclean; /* Should cleanup() remove output? */
int
main(int argc, char *argv[])
{
struct sigaction sa;
long i;
int ch;
const char *expr;
char *ep, *p;
FILE *ofp;
setlocale(LC_ALL, "");
kflag = sflag = 0;
prefix = "xx";
sufflen = 2;
while ((ch = getopt(argc, argv, "ksf:n:")) > 0) {
switch (ch) {
case 'f':
prefix = optarg;
break;
case 'k':
kflag = 1;
break;
case 'n':
errno = 0;
sufflen = strtol(optarg, &ep, 10);
if (sufflen <= 0 || *ep != '\0' || errno != 0)
errx(1, "%s: bad suffix length", optarg);
break;
case 's':
sflag = 1;
break;
default:
usage();
/*NOTREACHED*/
}
}
if (sufflen + strlen(prefix) >= PATH_MAX)
errx(1, "name too long");
argc -= optind;
argv += optind;
if ((infn = *argv++) == NULL)
usage();
if (strcmp(infn, "-") == 0) {
infile = stdin;
infn = "stdin";
} else if ((infile = fopen(infn, "r")) == NULL)
err(1, "%s", infn);
if (!kflag) {
doclean = 1;
atexit(cleanup);
sa.sa_flags = 0;
sa.sa_handler = handlesig;
sigemptyset(&sa.sa_mask);
sigaddset(&sa.sa_mask, SIGHUP);
sigaddset(&sa.sa_mask, SIGINT);
sigaddset(&sa.sa_mask, SIGTERM);
sigaction(SIGHUP, &sa, NULL);
sigaction(SIGINT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
}
lineno = 0;
nfiles = 0;
truncofs = 0;
overfile = NULL;
/* Ensure 10^sufflen < LONG_MAX. */
for (maxfiles = 1, i = 0; i < sufflen; i++) {
if (maxfiles > LONG_MAX / 10)
errx(1, "%ld: suffix too long (limit %ld)",
sufflen, i);
maxfiles *= 10;
}
/* Create files based on supplied patterns. */
while (nfiles < maxfiles - 1 && (expr = *argv++) != NULL) {
/* Look ahead & see if this pattern has any repetitions. */
if (*argv != NULL && **argv == '{') {
errno = 0;
reps = strtol(*argv + 1, &ep, 10);
if (reps < 0 || *ep != '}' || errno != 0)
errx(1, "%s: bad repetition count", *argv + 1);
argv++;
} else
reps = 0;
if (*expr == '/' || *expr == '%') {
do
do_rexp(expr);
while (reps-- != 0 && nfiles < maxfiles - 1);
} else if (isdigit((unsigned char)*expr))
do_lineno(expr);
else
errx(1, "%s: unrecognised pattern", expr);
}
/* Copy the rest into a new file. */
if (!feof(infile)) {
ofp = newfile();
while ((p = get_line()) != NULL && fputs(p, ofp) != EOF)
;
if (!sflag)
printf("%jd\n", (intmax_t)ftello(ofp));
if (fclose(ofp) != 0)
err(1, "%s", currfile);
}
toomuch(NULL, 0);
doclean = 0;
return (0);
}
static void
usage(void)
{
fprintf(stderr,
"usage: csplit [-ks] [-f prefix] [-n number] file args ...\n");
exit(1);
}
static void
handlesig(int sig __unused)
{
const char msg[] = "csplit: caught signal, cleaning up\n";
write(STDERR_FILENO, msg, sizeof(msg) - 1);
cleanup();
_exit(2);
}
/* Create a new output file. */
static FILE *
newfile(void)
{
FILE *fp;
if ((size_t)snprintf(currfile, sizeof(currfile), "%s%0*ld", prefix,
(int)sufflen, nfiles) >= sizeof(currfile))
errc(1, ENAMETOOLONG, NULL);
if ((fp = fopen(currfile, "w+")) == NULL)
err(1, "%s", currfile);
nfiles++;
return (fp);
}
/* Remove partial output, called before exiting. */
static void
cleanup(void)
{
char fnbuf[PATH_MAX];
long i;
if (!doclean)
return;
/*
* NOTE: One cannot portably assume to be able to call snprintf()
* from inside a signal handler. It does, however, appear to be safe
* to do on FreeBSD. The solution to this problem is worse than the
* problem itself.
*/
for (i = 0; i < nfiles; i++) {
snprintf(fnbuf, sizeof(fnbuf), "%s%0*ld", prefix,
(int)sufflen, i);
unlink(fnbuf);
}
}
/* Read a line from the input into a static buffer. */
static char *
get_line(void)
{
static char lbuf[LINE_MAX];
FILE *src;
src = overfile != NULL ? overfile : infile;
again: if (fgets(lbuf, sizeof(lbuf), src) == NULL) {
if (src == overfile) {
src = infile;
goto again;
}
return (NULL);
}
if (ferror(src))
err(1, "%s", infn);
lineno++;
return (lbuf);
}
/* Conceptually rewind the input (as obtained by get_line()) back `n' lines. */
static void
toomuch(FILE *ofp, long n)
{
char buf[BUFSIZ];
size_t i, nread;
if (overfile != NULL) {
/*
* Truncate the previous file we overflowed into back to
* the correct length, close it.
*/
if (fflush(overfile) != 0)
err(1, "overflow");
if (ftruncate(fileno(overfile), truncofs) != 0)
err(1, "overflow");
if (fclose(overfile) != 0)
err(1, "overflow");
overfile = NULL;
}
if (n == 0)
/* Just tidying up */
return;
lineno -= n;
/*
* Wind the overflow file backwards to `n' lines before the
* current one.
*/
do {
if (ftello(ofp) < (off_t)sizeof(buf))
rewind(ofp);
else
fseeko(ofp, -(off_t)sizeof(buf), SEEK_CUR);
if (ferror(ofp))
errx(1, "%s: can't seek", currfile);
if ((nread = fread(buf, 1, sizeof(buf), ofp)) == 0)
errx(1, "can't read overflowed output");
if (fseeko(ofp, -(off_t)nread, SEEK_CUR) != 0)
err(1, "%s", currfile);
for (i = 1; i <= nread; i++)
if (buf[nread - i] == '\n' && n-- == 0)
break;
if (ftello(ofp) == 0)
break;
} while (n > 0);
if (fseeko(ofp, nread - i + 1, SEEK_CUR) != 0)
err(1, "%s", currfile);
/*
* get_line() will read from here. Next call will truncate to
* truncofs in this file.
*/
overfile = ofp;
truncofs = ftello(overfile);
}
/* Handle splits for /regexp/ and %regexp% patterns. */
static void
do_rexp(const char *expr)
{
regex_t cre;
intmax_t nwritten;
long ofs;
int first;
char *ecopy, *ep, *p, *pofs, *re;
FILE *ofp;
if ((ecopy = strdup(expr)) == NULL)
err(1, "strdup");
re = ecopy + 1;
if ((pofs = strrchr(ecopy, *expr)) == NULL || pofs[-1] == '\\')
errx(1, "%s: missing trailing %c", expr, *expr);
*pofs++ = '\0';
if (*pofs != '\0') {
errno = 0;
ofs = strtol(pofs, &ep, 10);
if (*ep != '\0' || errno != 0)
errx(1, "%s: bad offset", pofs);
} else
ofs = 0;
if (regcomp(&cre, re, REG_BASIC|REG_NOSUB) != 0)
errx(1, "%s: bad regular expression", re);
if (*expr == '/')
/* /regexp/: Save results to a file. */
ofp = newfile();
else {
/* %regexp%: Make a temporary file for overflow. */
if ((ofp = tmpfile()) == NULL)
err(1, "tmpfile");
}
/* Read and output lines until we get a match. */
first = 1;
while ((p = get_line()) != NULL) {
if (fputs(p, ofp) == EOF)
break;
if (!first && regexec(&cre, p, 0, NULL, 0) == 0)
break;
first = 0;
}
if (p == NULL) {
toomuch(NULL, 0);
errx(1, "%s: no match", re);
}
if (ofs <= 0) {
/*
* Negative (or zero) offset: throw back any lines we should
* not have read yet.
*/
if (p != NULL) {
toomuch(ofp, -ofs + 1);
nwritten = (intmax_t)truncofs;
} else
nwritten = (intmax_t)ftello(ofp);
} else {
/*
* Positive offset: copy the requested number of lines
* after the match.
*/
while (--ofs > 0 && (p = get_line()) != NULL)
fputs(p, ofp);
toomuch(NULL, 0);
nwritten = (intmax_t)ftello(ofp);
if (fclose(ofp) != 0)
err(1, "%s", currfile);
}
if (!sflag && *expr == '/')
printf("%jd\n", nwritten);
regfree(&cre);
free(ecopy);
}
/* Handle splits based on line number. */
static void
do_lineno(const char *expr)
{
long lastline, tgtline;
char *ep, *p;
FILE *ofp;
errno = 0;
tgtline = strtol(expr, &ep, 10);
if (tgtline <= 0 || errno != 0 || *ep != '\0')
errx(1, "%s: bad line number", expr);
lastline = tgtline;
if (lastline <= lineno)
errx(1, "%s: can't go backwards", expr);
while (nfiles < maxfiles - 1) {
ofp = newfile();
while (lineno + 1 != lastline) {
if ((p = get_line()) == NULL)
errx(1, "%ld: out of range", lastline);
if (fputs(p, ofp) == EOF)
break;
}
if (!sflag)
printf("%jd\n", (intmax_t)ftello(ofp));
if (fclose(ofp) != 0)
err(1, "%s", currfile);
if (reps-- == 0)
break;
lastline += tgtline;
}
}