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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Copyright (c) 2026
* Project Tick. 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 <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
static int
write_all(const char *data, size_t len)
{
while (len > 0) {
ssize_t written;
written = write(STDOUT_FILENO, data, len);
if (written < 0) {
if (errno == EINTR)
continue;
return -1;
}
data += (size_t)written;
len -= (size_t)written;
}
return 0;
}
static void
warn_errno(const char *context)
{
fprintf(stderr, "echo: %s: %s\n", context, strerror(errno));
}
static bool
trim_trailing_backslash_c(const char *arg, size_t *len)
{
if (*len < 2)
return false;
if (arg[*len - 2] != '\\' || arg[*len - 1] != 'c')
return false;
*len -= 2;
return true;
}
int
main(int argc, char *argv[])
{
bool suppress_newline;
int first_arg;
suppress_newline = false;
first_arg = 1;
/*
* FreeBSD echo intentionally does not use getopt(3); only a leading
* literal "-n" is treated as an option.
*/
if (argc > 1 && strcmp(argv[1], "-n") == 0) {
suppress_newline = true;
first_arg = 2;
}
for (int i = first_arg; i < argc; i++) {
size_t len;
len = strlen(argv[i]);
if (i == argc - 1 && trim_trailing_backslash_c(argv[i], &len))
suppress_newline = true;
if (write_all(argv[i], len) < 0) {
warn_errno("write");
return 1;
}
if (i + 1 < argc && write_all(" ", 1) < 0) {
warn_errno("write");
return 1;
}
}
if (!suppress_newline && write_all("\n", 1) < 0) {
warn_errno("write");
return 1;
}
return 0;
}
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