/bin/echo/echo.c
https://bitbucket.org/freebsd/freebsd-head/ · C · 137 lines · 83 code · 13 blank · 41 comment · 16 complexity · 58d6242ad5cece48fb1a98ec36b13801 MD5 · raw file
- /*-
- * Copyright (c) 1989, 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.
- * 4. 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.
- */
- #if 0
- #ifndef lint
- static char const copyright[] =
- "@(#) Copyright (c) 1989, 1993\n\
- The Regents of the University of California. All rights reserved.\n";
- #endif /* not lint */
- #ifndef lint
- static char sccsid[] = "@(#)echo.c 8.1 (Berkeley) 5/31/93";
- #endif /* not lint */
- #endif
- #include <sys/cdefs.h>
- __FBSDID("$FreeBSD$");
- #include <sys/types.h>
- #include <sys/uio.h>
- #include <assert.h>
- #include <errno.h>
- #include <limits.h>
- #include <stdlib.h>
- #include <string.h>
- #include <unistd.h>
- /*
- * Report an error and exit.
- * Use it instead of err(3) to avoid linking-in stdio.
- */
- static __dead2 void
- errexit(const char *prog, const char *reason)
- {
- char *errstr = strerror(errno);
- write(STDERR_FILENO, prog, strlen(prog));
- write(STDERR_FILENO, ": ", 2);
- write(STDERR_FILENO, reason, strlen(reason));
- write(STDERR_FILENO, ": ", 2);
- write(STDERR_FILENO, errstr, strlen(errstr));
- write(STDERR_FILENO, "\n", 1);
- exit(1);
- }
-
- int
- main(int argc, char *argv[])
- {
- int nflag; /* if not set, output a trailing newline. */
- int veclen; /* number of writev arguments. */
- struct iovec *iov, *vp; /* Elements to write, current element. */
- char space[] = " ";
- char newline[] = "\n";
- char *progname = argv[0];
- /* This utility may NOT do getopt(3) option parsing. */
- if (*++argv && !strcmp(*argv, "-n")) {
- ++argv;
- --argc;
- nflag = 1;
- } else
- nflag = 0;
- veclen = (argc >= 2) ? (argc - 2) * 2 + 1 : 0;
- if ((vp = iov = malloc((veclen + 1) * sizeof(struct iovec))) == NULL)
- errexit(progname, "malloc");
- while (argv[0] != NULL) {
- size_t len;
-
- len = strlen(argv[0]);
- /*
- * If the next argument is NULL then this is this
- * the last argument, therefore we need to check
- * for a trailing \c.
- */
- if (argv[1] == NULL) {
- /* is there room for a '\c' and is there one? */
- if (len >= 2 &&
- argv[0][len - 2] == '\\' &&
- argv[0][len - 1] == 'c') {
- /* chop it and set the no-newline flag. */
- len -= 2;
- nflag = 1;
- }
- }
- vp->iov_base = *argv;
- vp++->iov_len = len;
- if (*++argv) {
- vp->iov_base = space;
- vp++->iov_len = 1;
- }
- }
- if (!nflag) {
- veclen++;
- vp->iov_base = newline;
- vp++->iov_len = 1;
- }
- /* assert(veclen == (vp - iov)); */
- while (veclen) {
- int nwrite;
- nwrite = (veclen > IOV_MAX) ? IOV_MAX : veclen;
- if (writev(STDOUT_FILENO, iov, nwrite) == -1)
- errexit(progname, "write");
- iov += nwrite;
- veclen -= nwrite;
- }
- return 0;
- }