Add 'corebinutils/echo/' from commit '74324d021b4424d2b9b21a8593f4c7680837a275'

git-subtree-dir: corebinutils/echo
git-subtree-mainline: 46f7aa5f7802807c850fcfdd3ec1e2072f7e9d94
git-subtree-split: 74324d021b4424d2b9b21a8593f4c7680837a275

1 files changed, 120 insertions, 0 deletions

diff --git a/corebinutils/echo/echo.c b/corebinutils/echo/echo.c
new file mode 100644
index 0000000000..0074f968db
--- /dev/null
+++ b/corebinutils/echo/echo.c
@@ -0,0 +1,120 @@
+/*-
+ * 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;
+}