diff options
Diffstat (limited to 'usr.bin/head/head.c')
| -rw-r--r-- | usr.bin/head/head.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/usr.bin/head/head.c b/usr.bin/head/head.c new file mode 100644 index 0000000..1d24d48 --- /dev/null +++ b/usr.bin/head/head.c @@ -0,0 +1,204 @@ +/* $NetBSD: head.c,v 1.24 2016/05/12 01:56:44 nonaka Exp $ */ + +/* + * Copyright (c) 1980, 1987, 1992, 1993 + * The Regents of the University of California. 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. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. + */ + +#include <sys/cdefs.h> +#ifndef lint +__COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1992, 1993\ + The Regents of the University of California. All rights reserved."); +#endif /* not lint */ + +#ifndef lint +#if 0 +static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; +#else +__RCSID("$NetBSD: head.c,v 1.24 2016/05/12 01:56:44 nonaka Exp $"); +#endif +#endif /* not lint */ + +#include <sys/types.h> + +#include <ctype.h> +#include <err.h> +#include <errno.h> +#include <inttypes.h> +#include <limits.h> +#include <locale.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +/* + * head - give the first few lines of a stream or of each of a set of files + * + * Bill Joy UCB August 24, 1977 + */ + +static void head(FILE *, intmax_t, intmax_t); +static void obsolete(char *[]); +__dead static void usage(void); + + +int +main(int argc, char *argv[]) +{ + int ch; + FILE *fp; + int first; + intmax_t linecnt; + intmax_t bytecnt; + char *ep; + int eval = 0; + int qflag = 0; + int vflag = 0; + + (void)setlocale(LC_ALL, ""); + obsolete(argv); + linecnt = 10; + bytecnt = 0; + while ((ch = getopt(argc, argv, "c:n:qv")) != -1) + switch(ch) { + case 'c': + errno = 0; + bytecnt = strtoimax(optarg, &ep, 10); + if ((bytecnt == INTMAX_MAX && errno == ERANGE) || + *ep || bytecnt <= 0) + errx(1, "illegal byte count -- %s", optarg); + break; + + case 'n': + errno = 0; + linecnt = strtoimax(optarg, &ep, 10); + if ((linecnt == INTMAX_MAX && errno == ERANGE) || + *ep || linecnt <= 0) + errx(1, "illegal line count -- %s", optarg); + break; + + case 'q': + qflag = 1; + vflag = 0; + break; + + case 'v': + qflag = 0; + vflag = 1; + break; + + case '?': + default: + usage(); + } + argc -= optind; + argv += optind; + + if (*argv) + for (first = 1; *argv; ++argv) { + if ((fp = fopen(*argv, "r")) == NULL) { + warn("%s", *argv); + eval = 1; + continue; + } + if (vflag || (qflag == 0 && argc > 1)) { + (void)printf("%s==> %s <==\n", + first ? "" : "\n", *argv); + first = 0; + } + head(fp, linecnt, bytecnt); + (void)fclose(fp); + } + else + head(stdin, linecnt, bytecnt); + exit(eval); +} + +static void +head(FILE *fp, intmax_t cnt, intmax_t bytecnt) +{ + char buf[65536]; + size_t len, rv, rv2; + int ch; + + if (bytecnt) { + while (bytecnt) { + len = sizeof(buf); + if (bytecnt > (intmax_t)sizeof(buf)) + len = sizeof(buf); + else + len = bytecnt; + rv = fread(buf, 1, len, fp); + if (rv == 0) + break; /* Distinguish EOF and error? */ + rv2 = fwrite(buf, 1, rv, stdout); + if (rv2 != rv) { + if (feof(stdout)) + errx(1, "EOF on stdout"); + else + err(1, "failure writing to stdout"); + } + bytecnt -= rv; + } + } else { + while ((ch = getc(fp)) != EOF) { + if (putchar(ch) == EOF) + err(1, "stdout"); + if (ch == '\n' && --cnt == 0) + break; + } + } +} + +static void +obsolete(char *argv[]) +{ + char *ap; + + while ((ap = *++argv)) { + /* Return if "--" or not "-[0-9]*". */ + if (ap[0] != '-' || ap[1] == '-' || + !isdigit((unsigned char)ap[1])) + return; + if ((ap = malloc(strlen(*argv) + 2)) == NULL) + err(1, NULL); + ap[0] = '-'; + ap[1] = 'n'; + (void)strcpy(ap + 2, *argv + 1); + *argv = ap; + } +} + +static void +usage(void) +{ + + (void)fprintf(stderr, "usage: %s [-n lines] [file ...]\n", + getprogname()); + exit(1); +} |