hare

commit 568fe624fc236a2cc0f97f0a501ab4d77e66c9b1
parent 3ba88ee45d9844b414b8d40f228f0527c523152a
Author: Bor Grošelj Simić <bor.groseljsimic@telemach.net>
Date:   Fri, 18 Feb 2022 10:09:48 +0100

os::exec: expand waitpid functionality

Add os::exec::waitany that waits for whichever child terminates first
and os::exec::waitall that waits for all child processes.

Implements: https://todo.sr.ht/~sircmpwn/hare/519
Signed-off-by: Bor Grošelj Simić <bor.groseljsimic@telemach.net>

Diffstat:
M
os/exec/process+freebsd.ha
 | 
38
+++++++++++++++++++++++++++++++++++++-
M
os/exec/process+linux.ha
 | 
38
+++++++++++++++++++++++++++++++++++++-

2 files changed, 74 insertions(+), 2 deletions(-)
diff --git a/os/exec/process+freebsd.ha b/os/exec/process+freebsd.ha
@@ -1,7 +1,6 @@
 use errors;
 use rt;
 use fmt;
-// TODO: Add function to wait on all/any children
 
 // Stores information about a child process.
 export type process = int;
@@ -66,6 +65,43 @@ export fn wait(proc: *process) (status | error) = {
 	return st;
 };
 
+// Waits for the first child process to complete, then returns its process info
+// and status
+export fn waitany() ((process, status) | error) = {
+	let ru: rt::rusage = rt::rusage { ... };
+	let st: status = status { ... };
+	match (rt::wait4(-1, &st.status, 0, &ru)) {
+	case let err: rt::errno =>
+		return errors::errno(err);
+	case let pid: int =>
+		rusage(&st, &ru);
+		return (pid, st);
+	};
+};
+
+// Waits for all children to terminate succesfully. If a child process exits
+// with a nonzero status, returns its process info and exit status immediately,
+// not waiting for the remaining children.
+export fn waitall() (uint | error | !(process, exit_status)) = {
+	let st: status = status { ... };
+	let ru: rt::rusage = rt::rusage { ... };
+	for (let i = 0u; true; i += 1) match (rt::wait4(-1, &st.status, 0, &ru)) {
+	case let err: rt::errno =>
+		if (err: int == rt::ECHILD) {
+			return i;
+		} else {
+			return errors::errno(err);
+		};
+	case let pid: int =>
+		match (check(&st)) {
+		case void => void;
+		case let es: !exit_status =>
+			return (pid, es);
+		};
+	};
+	abort("unreachable");
+};
+
 // Checks for process completion, returning its status information on
 // completion, or void if it is still running.
 export fn peek(proc: *process) (status | void | error) = {
diff --git a/os/exec/process+linux.ha b/os/exec/process+linux.ha
@@ -1,7 +1,6 @@
 use errors;
 use rt;
 use fmt;
-// TODO: Add function to wait on all/any children
 
 // Stores information about a child process.
 export type process = int;
@@ -52,6 +51,43 @@ export fn wait(proc: *process) (status | error) = {
 	return st;
 };
 
+// Waits for the first child process to complete, then returns its process info
+// and status
+export fn waitany() ((process, status) | error) = {
+	let ru: rt::rusage = rt::rusage { ... };
+	let st: status = status { ... };
+	match (rt::wait4(-1, &st.status, 0, &ru)) {
+	case let err: rt::errno =>
+		return errors::errno(err);
+	case let pid: int =>
+		rusage(&st, &ru);
+		return (pid, st);
+	};
+};
+
+// Waits for all children to terminate succesfully. If a child process exits
+// with a nonzero status, returns its process info and exit status immediately,
+// not waiting for the remaining children.
+export fn waitall() (uint | error | !(process, exit_status)) = {
+	let st: status = status { ... };
+	let ru: rt::rusage = rt::rusage { ... };
+	for (let i = 0u; true; i += 1) match (rt::wait4(-1, &st.status, 0, &ru)) {
+	case let err: rt::errno =>
+		if (err: int == rt::ECHILD) {
+			return i;
+		} else {
+			return errors::errno(err);
+		};
+	case let pid: int =>
+		match (check(&st)) {
+		case void => void;
+		case let es: !exit_status =>
+			return (pid, es);
+		};
+	};
+	abort("unreachable");
+};
+
 // Checks for process completion, returning its status information on
 // completion, or void if it is still running.
 export fn peek(proc: *process) (status | void | error) = {