From f783a3d9b01b1214c3f928deddc86ae5a746ebd4 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Thu, 8 Jun 2023 16:56:25 -0700
Subject: MacOS port.

- The poll function is broken on Darwin (won't handle devices).
  We make a macpoll out of select and use that.

- Makefile adds _D_DARWIN_C_SOURCE to CFLAGS.
---
 Makefile  |  6 +++--
 macpoll.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 macpoll.h |  2 ++
 pw.c      |  3 +++
 4 files changed, 92 insertions(+), 2 deletions(-)
 create mode 100644 macpoll.c
 create mode 100644 macpoll.h

diff --git a/Makefile b/Makefile
index f85adbf..9b507f4 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,7 @@
 PW_SHA256 := 7361c87eb5e55240a3afbf7f41bc2a08f93e392414103075d3929b5fd53e021c
+DARWIN = $(findstring Darwin,$(shell uname))
 NEEDED_CFLAGS := -std=c99 -D_POSIX_C_SOURCE=200112L -D__EXTENSIONS__
+NEEDED_CFLAGS += $(if $(DARWIN),-D_DARWIN_C_SOURCE)
 ifeq ($(shell sha256sum pw.c),$(PW_SHA256)  pw.c)
 PW_VERSION := 3
 else
@@ -11,8 +13,8 @@ override CFLAGS += $(NEEDED_CFLAGS) -DCONFIG_PW_VER=\"$(PW_VERSION)\"
 DESTDIR ?= /usr/local
 .PHONY: all fixver
 all: pw fixver
-pw:
-clean:; rm -f pw
+pw: $(if $(DARWIN),macpoll.o)
+clean:; rm -f pw macpoll.o
 install:; install pw $(DESTDIR)/bin/pw; \
           install -D pw.1 $(DESTDIR)/share/man/man1/pw.1; \
           install -D pw-relnotes.5 $(DESTDIR)/share/man/man5/pw-relnotes.5
diff --git a/macpoll.c b/macpoll.c
new file mode 100644
index 0000000..82e87ac
--- /dev/null
+++ b/macpoll.c
@@ -0,0 +1,83 @@
+// Pipe Watch ("pw")
+// Copyright 2022-2023 Kaz Kylheku <kaz@kylheku.com>
+//
+// BSD-2 License
+//
+// 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.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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 <stddef.h>
+#include <sys/select.h>
+#include <poll.h>
+#include <limits.h>
+
+// Would you believe it? MacOS poll() does not support devices, such as TTYs.
+// Here we implement a lame poll using the inefficient select function.
+
+int macpoll(struct pollfd *fds, nfds_t nfds, int timeout)
+{
+  fd_set readfds, writefds, exceptfds;
+  struct timeval tv;
+  int maxfd = 0;
+
+  FD_ZERO(&readfds);
+  FD_ZERO(&writefds);
+  FD_ZERO(&exceptfds);
+
+  for (nfds_t i = 0; i < nfds; i++) {
+    int events = fds[i].events;
+    int fd = fds[i].fd;
+    if (fd < 0)
+      continue;
+    if (fd > maxfd)
+      maxfd = fd;
+    if (events & POLLIN)
+      FD_SET(fd, &readfds);
+    if (events & POLLOUT)
+      FD_SET(fd, &writefds);
+    if (events & POLLERR)
+      FD_SET(fd, &exceptfds);
+  }
+
+  tv.tv_sec = timeout / 1000;
+  tv.tv_usec = (timeout % 1000) * 1000;
+
+  int ret = select(maxfd + 1, &readfds, &writefds, &exceptfds,
+                   timeout >= 0 ? &tv : NULL);
+
+  if (ret >= 0) {
+    for (nfds_t i = 0; i < nfds; i++) {
+      int fd = fds[i].fd;
+      int revents = 0;
+      fds[i].revents = 0;
+      if (FD_ISSET(fd, &readfds))
+        revents |= POLLIN;
+      if (FD_ISSET(fd, &writefds))
+        revents |= POLLOUT;
+      if (FD_ISSET(fd, &exceptfds))
+        revents |= POLLERR;
+      fds[i].revents = revents;
+    }
+  }
+
+  return ret;
+}
diff --git a/macpoll.h b/macpoll.h
new file mode 100644
index 0000000..95dfc04
--- /dev/null
+++ b/macpoll.h
@@ -0,0 +1,2 @@
+int macpoll(struct pollfd *fds, nfds_t nfds, int timeout);
+#define poll macpoll
diff --git a/pw.c b/pw.c
index 68bf58c..23a7beb 100644
--- a/pw.c
+++ b/pw.c
@@ -44,6 +44,9 @@
 #include <errno.h>
 #include <signal.h>
 #include <regex.h>
+#ifdef _DARWIN_C_SOURCE
+#include "macpoll.h"
+#endif
 
 #define ctrl(ch) ((ch) & 0x1f)
 #define BS 8
-- 
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