From b61c07af798557eff4333716c917c99a4f0c13c6 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Mon, 13 Oct 2025 16:14:02 -0400
Subject: kern: proc: Add initial waitpid() syscall

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 src/sys/include/compat/unix/syscall.h |  3 ++-
 src/sys/include/sys/proc.h            |  5 +++++
 src/sys/include/sys/syscall.h         |  1 +
 src/sys/os/os_proc.c                  | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 40 insertions(+), 1 deletion(-)

(limited to 'src/sys')

diff --git a/src/sys/include/compat/unix/syscall.h b/src/sys/include/compat/unix/syscall.h
index 7a612c3..13bd617 100644
--- a/src/sys/include/compat/unix/syscall.h
+++ b/src/sys/include/compat/unix/syscall.h
@@ -74,7 +74,8 @@ scret_t(*g_unix_sctab[])(struct syscall_args *) = {
     [SYS_open]   = sys_open,
     [SYS_muxtap] = sys_muxtap,
     [SYS_getargv] = sys_getargv,
-    [SYS_reboot]  = sys_reboot
+    [SYS_reboot]  = sys_reboot,
+    [SYS_waitpid] = sys_waitpid
 };
 
 #endif  /* !_NEED_UNIX_SCTAB */
diff --git a/src/sys/include/sys/proc.h b/src/sys/include/sys/proc.h
index bb34066..618ddf3 100644
--- a/src/sys/include/sys/proc.h
+++ b/src/sys/include/sys/proc.h
@@ -263,5 +263,10 @@ scret_t sys_spawn(struct syscall_args *scargs);
  */
 scret_t sys_getargv(struct syscall_args *scargs);
 
+/*
+ * Wait for a child to complete
+ */
+scret_t sys_waitpid(struct syscall_args *scargs);
+
 #endif  /* !_KERNEL */
 #endif  /* !_SYS_PROC_H_ */
diff --git a/src/sys/include/sys/syscall.h b/src/sys/include/sys/syscall.h
index 9616aed..ac03055 100644
--- a/src/sys/include/sys/syscall.h
+++ b/src/sys/include/sys/syscall.h
@@ -54,6 +54,7 @@
 #define SYS_muxtap      0x09    /* mux an I/O tap */
 #define SYS_getargv     0x0A    /* get process argv */
 #define SYS_reboot      0x0B    /* reboot the system */
+#define SYS_waitpid     0x0C    /* wait for child to exit */
 
 typedef __ssize_t scret_t;
 typedef __ssize_t scarg_t;
diff --git a/src/sys/os/os_proc.c b/src/sys/os/os_proc.c
index 4ee4fd8..764b3f2 100644
--- a/src/sys/os/os_proc.c
+++ b/src/sys/os/os_proc.c
@@ -439,3 +439,35 @@ sys_getargv(struct syscall_args *scargs)
     arg = envblk->argv[argno];
     return copyoutstr(arg, u_buf, maxlen);
 }
+
+/*
+ * Wait for a child to complete
+ *
+ * ARG0: PID
+ * ARG1: Status
+ * ARG2: Options
+ */
+scret_t
+sys_waitpid(struct syscall_args *scargs)
+{
+    int pid = SCARG(scargs, int, 0);
+    int *u_status = SCARG(scargs, int *, 1);
+    int status = 0;
+    int error = 0;
+    struct proc *proc, *self;
+
+    if ((proc = proc_lookup(pid)) == NULL) {
+        return -ESRCH;
+    }
+
+    if (u_status != NULL) {
+        error = copyout(&status, u_status, sizeof(*u_status));
+    }
+    if (error < 0) {
+        return error;
+    }
+
+    self = proc_self();
+    proc_sleep(self);
+    return 0;
+}
-- 
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