From 4b8c1ac2d2d5c13d7c8592fd6d94b34a6a8b3549 Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Sun, 8 Oct 2023 11:09:00 -0500
Subject: [PATCH 1/4] Add os/posix-fork

Very simple fork function that returns a process object that can be
waited on.
---
 src/core/os.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/core/os.c b/src/core/os.c
index 460cb7eb..091a0c6f 100644
--- a/src/core/os.c
+++ b/src/core/os.c
@@ -2340,6 +2340,34 @@ JANET_CORE_FN(os_permission_int,
     return janet_wrap_integer(os_get_unix_mode(argv, 0));
 }
 
+JANET_CORE_FN(os_posix_fork,
+        "(os/posix-fork)",
+        "Make a `fork` system call and create a new process. Return nil if in the new process, otherwise a core/proc object (as returned by os/spawn). "
+        "Not supported on all system (POSIX only).") {
+    janet_sandbox_assert(JANET_SANDBOX_SUBPROCESS);
+    janet_fixarity(argc, 0);
+    (void) argv;
+#ifdef JANET_WINDOWS
+    janet_panic("not supported");
+#else
+    pid_t result;
+    do {
+        result = fork();
+    } while (result == -1 && errno == EINTR);
+    if (result == -1) {
+        janet_panic(strerror(errno));
+    }
+    if (result) {
+        JanetProc *proc = janet_abstract(&ProcAT, sizeof(JanetProc));
+        memset(proc, 0, sizeof(JanetProc));
+        proc->pid = result;
+        proc->flags = JANET_PROC_ALLOW_ZOMBIE;
+        return janet_wrap_abstract(proc);
+    }
+    return janet_wrap_nil();
+#endif
+}
+
 #ifdef JANET_EV
 
 /*
@@ -2626,6 +2654,7 @@ void janet_lib_os(JanetTable *env) {
         JANET_CORE_REG("os/execute", os_execute),
         JANET_CORE_REG("os/spawn", os_spawn),
         JANET_CORE_REG("os/shell", os_shell),
+        JANET_CORE_REG("os/posix-fork", os_posix_fork),
         /* no need to sandbox process management if you can't create processes
          * (allows for limited functionality if use exposes C-functions to create specific processes) */
         JANET_CORE_REG("os/proc-wait", os_proc_wait),

From cf4901e71372d0a5553dbdf82a578f892565a6a0 Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Sun, 8 Oct 2023 11:35:08 -0500
Subject: [PATCH 2/4] Update docstring for os/posix-fork

---
 src/core/os.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/core/os.c b/src/core/os.c
index 091a0c6f..64f6920d 100644
--- a/src/core/os.c
+++ b/src/core/os.c
@@ -2342,8 +2342,8 @@ JANET_CORE_FN(os_permission_int,
 
 JANET_CORE_FN(os_posix_fork,
         "(os/posix-fork)",
-        "Make a `fork` system call and create a new process. Return nil if in the new process, otherwise a core/proc object (as returned by os/spawn). "
-        "Not supported on all system (POSIX only).") {
+        "Make a `fork` system call and create a new process. Return nil if in the new process, otherwise a core/process object (as returned by os/spawn). "
+        "Not supported on all systems (POSIX only).") {
     janet_sandbox_assert(JANET_SANDBOX_SUBPROCESS);
     janet_fixarity(argc, 0);
     (void) argv;

From 5442c8e86df3d21ff903a4e89e46f726160b085e Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Sun, 8 Oct 2023 12:34:13 -0500
Subject: [PATCH 3/4] Add EV_EOF and EV_CLEAR to selfpipe for kqueue

---
 src/core/ev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/core/ev.c b/src/core/ev.c
index 057296a7..823a13e3 100644
--- a/src/core/ev.c
+++ b/src/core/ev.c
@@ -1900,7 +1900,7 @@ void janet_ev_init(void) {
     janet_vm.timer_enabled = 0;
     if (janet_vm.kq == -1) goto error;
     struct kevent event;
-    EV_SETx(&event, janet_vm.selfpipe[0], EVFILT_READ, EV_ADD | EV_ENABLE, 0, 0, janet_vm.selfpipe);
+    EV_SETx(&event, janet_vm.selfpipe[0], EVFILT_READ, EV_ADD | EV_ENABLE | EV_EOF | EV_CLEAR, 0, 0, janet_vm.selfpipe);
     add_kqueue_events(&event, 1);
     return;
 error:

From d71c100ca7338270d8e41dbd0bd3385cd2140c7f Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Sun, 8 Oct 2023 13:13:58 -0500
Subject: [PATCH 4/4] Revert "Add EV_EOF and EV_CLEAR to selfpipe for kqueue"

This reverts commit 5442c8e86df3d21ff903a4e89e46f726160b085e.
---
 src/core/ev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/core/ev.c b/src/core/ev.c
index 823a13e3..057296a7 100644
--- a/src/core/ev.c
+++ b/src/core/ev.c
@@ -1900,7 +1900,7 @@ void janet_ev_init(void) {
     janet_vm.timer_enabled = 0;
     if (janet_vm.kq == -1) goto error;
     struct kevent event;
-    EV_SETx(&event, janet_vm.selfpipe[0], EVFILT_READ, EV_ADD | EV_ENABLE | EV_EOF | EV_CLEAR, 0, 0, janet_vm.selfpipe);
+    EV_SETx(&event, janet_vm.selfpipe[0], EVFILT_READ, EV_ADD | EV_ENABLE, 0, 0, janet_vm.selfpipe);
     add_kqueue_events(&event, 1);
     return;
 error: