core/: tee

Signed-off-by: Ferass El Hafidi <vitali64pmemail@protonmail.com>

2 files changed, 54 insertions, 0 deletions

diff --git a/config.mk b/config.mk
index 3d3a4aa..4c263e7 100644
--- a/config.mk
+++ b/config.mk
@@ -31,6 +31,7 @@ CORE=\
 	rm\
 	sleep\
 	tail\
+	tee\
 	test\
 	true\
 	tty\
diff --git a/core/tee.c b/core/tee.c
new file mode 100644
index 0000000..f84f316
--- /dev/null
+++ b/core/tee.c
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+#include <stdio.h>
+#include <unistd.h>
+#include <signal.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <string.h>
+
+/* Requirements in common.h */
+#define REQ_PRINT_USAGE
+#define REQ_ERRPRINT
+#include "../common/common.h"
+
+#define DESCRIPTION "Duplicate standard input."
+#define OPERANDS    "[-ai] [file...]"
+
+int main(int argc, char *argv[]) {
+	int argument, length, i = 0, fildes[13], append_or_truncate = O_TRUNC;
+	int ret = 0; /* Used for write errors. */
+	char *argv0 = strdup(argv[0]), buffer[4096];
+
+	while ((argument = getopt(argc, argv, "ai")) != -1) {
+		if (argument == '?')
+			return print_usage(argv0, DESCRIPTION, OPERANDS, VERSION);
+		else if (argument == 'i') {
+			struct sigaction signal_action;
+			signal_action.sa_handler = SIG_IGN;
+			sigemptyset(&signal_action.sa_mask);
+			sigaction(SIGINT, &signal_action, NULL);
+		} else if (argument == 'a')
+			append_or_truncate = O_APPEND;
+	} argc -= optind; argv += optind;
+	/* Open all files */
+	for (i = 0; i < argc && argc != 0 && i <= 13; i++) { /* TODO: No file limit */
+		fildes[i] = open(argv[i], O_WRONLY | O_CREAT | append_or_truncate, 0666);
+		if (errno) return errprint(argv0, argv[i], errno);
+	}
+	while ((length = read(STDIN_FILENO, buffer, 4096)) > 0) {
+		write(STDOUT_FILENO, buffer, length); /* Write to stdout. */
+		/* ...And to all other files */
+		for (i = 0; i < argc && argc != 0 && i <= 13; i++) {
+			write(fildes[i], buffer, length);
+			if (errno) ret = errprint(argv0, argv[i], length);
+		}
+	}
+	for (i = 0; i < argc && argc != 0 && i <= 13; i++) {
+		close(fildes[i]);
+		if (errno) return errprint(argv0, argv[i], errno);
+	}
+
+	return ret;
+}