1 files changed, 116 insertions, 0 deletions
diff --git a/bin/ever.c b/bin/ever.c
new file mode 100644
index 00000000..7838af4b
--- /dev/null
+++ b/bin/ever.c
@@ -0,0 +1,116 @@
+/* Copyright (C) 2017  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sys/types.h>
+
+#include <err.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <sys/event.h>
+#include <sys/wait.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+static int watch(int kq, char *path) {
+	int fd = open(path, O_CLOEXEC);
+	if (fd < 0) err(EX_NOINPUT, "%s", path);
+
+	struct kevent event;
+	EV_SET(
+		&event,
+		fd,
+		EVFILT_VNODE,
+		EV_ADD | EV_CLEAR,
+		NOTE_WRITE | NOTE_DELETE,
+		0,
+		path
+	);
+	int nevents = kevent(kq, &event, 1, NULL, 0, NULL);
+	if (nevents < 0) err(EX_OSERR, "kevent");
+
+	return fd;
+}
+
+static void exec(int fd, char *const argv[]) {
+	pid_t pid = fork();
+	if (pid < 0) err(EX_OSERR, "fork");
+
+	if (!pid) {
+		dup2(fd, STDIN_FILENO);
+		execvp(*argv, argv);
+		err(EX_NOINPUT, "%s", *argv);
+	}
+
+	int status;
+	pid = wait(&status);
+	if (pid < 0) err(EX_OSERR, "wait");
+
+	if (WIFEXITED(status)) {
+		warnx("exit %d\n", WEXITSTATUS(status));
+	} else if (WIFSIGNALED(status)) {
+		warnx("signal %d\n", WTERMSIG(status));
+	} else {
+		warnx("status %d\n", status);
+	}
+}
+
+int main(int argc, char *argv[]) {
+	bool input = false;
+
+	for (int opt; 0 < (opt = getopt(argc, argv, "i"));) {
+		switch (opt) {
+			break; case 'i': input = true;
+			break; default:  return EX_USAGE;
+		}
+	}
+	argc -= optind;
+	argv += optind;
+	if (argc < 2) return EX_USAGE;
+
+	int kq = kqueue();
+	if (kq < 0) err(EX_OSERR, "kqueue");
+
+	int i;
+	for (i = 0; i < argc - 1; ++i) {
+		if (argv[i][0] == '-') {
+			i++;
+			break;
+		}
+		watch(kq, argv[i]);
+	}
+
+	if (!input) {
+		exec(STDIN_FILENO, &argv[i]);
+	}
+
+	for (;;) {
+		struct kevent event;
+		int nevents = kevent(kq, NULL, 0, &event, 1, NULL);
+		if (nevents < 0) err(EX_OSERR, "kevent");
+
+		if (event.fflags & NOTE_DELETE) {
+			close(event.ident);
+			sleep(1);
+			event.ident = watch(kq, (char *)event.udata);
+		} else if (input) {
+			off_t off = lseek(event.ident, 0, SEEK_SET);
+			if (off < 0) err(EX_IOERR, "lseek");
+		}
+
+		exec((input ? event.ident : STDIN_FILENO), &argv[i]);
+	}
+}