ww: give captured actions null stdin

lib/os/exec/exec.ww

@@ -28,13 +28,14 @@ export type result = struct {
 
 // command is deliberately concrete.  argv includes argv[0], env is the full
 // environment, and an empty dir inherits the caller's working directory.
-// stdoutpath and stderrpath are created exclusively with mode 0600.  A zero
+// An empty stdinpath selects the null device; stdoutpath and stderrpath are
-// deadline means no timeout.
+// created exclusively with mode 0600.  A zero deadline means no timeout.
 export type command = struct {
 	path: str,
 	argv: []str,
 	env: []str,
 	dir: str,
+	stdinpath: str,
 	stdoutpath: str,
 	stderrpath: str,
 	deadline: time.instant,
@@ -124,7 +125,8 @@ fn valid(c: *command) bool = {
 		return false;
 	};
 	if ((c.grace: i64) < 0i64) { return false; };
-	if (hasnul(c.path) || hasnul(c.dir) || hasnul(c.stdoutpath)
+	if (hasnul(c.path) || hasnul(c.dir) || hasnul(c.stdinpath)
+	    || hasnul(c.stdoutpath)
 	    || hasnul(c.stderrpath)) {
 		return false;
 	};
@@ -209,8 +211,8 @@ fn childclose(fd: i32, markerfd: i32) void = {
 	if (rc < 0) { childmark(markerfd, rc); };
 };
 
-fn child(c: *command, av: []*u8, ep: []*u8, outfd: i32,
+fn child(c: *command, av: []*u8, ep: []*u8, infd: i32,
-	errfd: i32, markerread: i32, markerwrite: i32) void = {
+	outfd: i32, errfd: i32, markerread: i32, markerwrite: i32) void = {
 	let rc: i32 = os.setpgid(0, 0);
 	if (rc < 0) { childmark(markerwrite, rc); };
 	if (launchmaskactive) {
@@ -218,6 +220,9 @@ fn child(c: *command, av: []*u8, ep: []*u8, outfd: i32,
 		if (rc < 0) { childmark(markerwrite, rc); };
 	};
 	childclose(markerread, markerwrite);
+	rc = os.dup2(infd, os.STDIN_FILENO);
+	if (rc < 0) { childmark(markerwrite, rc); };
+	childclose(infd, markerwrite);
 	rc = os.dup2(outfd, os.STDOUT_FILENO);
 	if (rc < 0) { childmark(markerwrite, rc); };
 	rc = os.dup2(errfd, os.STDERR_FILENO);
@@ -238,21 +243,37 @@ export fn start(p: *process, c: *command) void = {
 	p.hasdeadline = c.deadline.sec != 0i64 || c.deadline.nsec != 0i64;
 	p.grace = c.grace;
 	if (!valid(c)) { fail(p, 22); return; };
+	let stdinpath: str = c.stdinpath;
+	if (stdinpath.len == 0) { stdinpath = "/dev/null"; };
+	let infd: i32 = os.open(stdinpath, os.flag.RDONLY, 0i32);
+	if (infd < 0) { fail(p, infd); return; };
+	infd = safefd(&p.result, infd);
+	if (infd < 0) { fail(p, infd); return; };
 	let outfd: i32 = os.open(c.stdoutpath,
 		os.flag.WRONLY | os.flag.CREATE | os.flag.EXCL, 384);
-	if (outfd < 0) { fail(p, outfd); return; };
+	if (outfd < 0) {
+		fail(p, outfd);
+		closefd(&p.result, infd);
+		return;
+	};
 	outfd = safefd(&p.result, outfd);
-	if (outfd < 0) { fail(p, outfd); return; };
+	if (outfd < 0) {
+		fail(p, outfd);
+		closefd(&p.result, infd);
+		return;
+	};
 	let errfd: i32 = os.open(c.stderrpath,
 		os.flag.WRONLY | os.flag.CREATE | os.flag.EXCL, 384);
 	if (errfd < 0) {
 		fail(p, errfd);
+		closefd(&p.result, infd);
 		closefd(&p.result, outfd);
 		return;
 	};
 	errfd = safefd(&p.result, errfd);
 	if (errfd < 0) {
 		fail(p, errfd);
+		closefd(&p.result, infd);
 		closefd(&p.result, outfd);
 		return;
 	};
@@ -260,6 +281,7 @@ export fn start(p: *process, c: *command) void = {
 	let rc: i32 = os.pipe2(&marker, os.O_CLOEXEC | os.O_NONBLOCK);
 	if (rc < 0) {
 		fail(p, rc);
+		closefd(&p.result, infd);
 		closefd(&p.result, outfd);
 		closefd(&p.result, errfd);
 		return;
@@ -267,6 +289,7 @@ export fn start(p: *process, c: *command) void = {
 	marker[0] = safefd(&p.result, marker[0]);
 	if (marker[0] < 0) {
 		fail(p, marker[0]);
+		closefd(&p.result, infd);
 		closefd(&p.result, outfd);
 		closefd(&p.result, errfd);
 		closefd(&p.result, marker[1]);
@@ -275,6 +298,7 @@ export fn start(p: *process, c: *command) void = {
 	marker[1] = safefd(&p.result, marker[1]);
 	if (marker[1] < 0) {
 		fail(p, marker[1]);
+		closefd(&p.result, infd);
 		closefd(&p.result, outfd);
 		closefd(&p.result, errfd);
 		closefd(&p.result, marker[0]);
@@ -285,16 +309,20 @@ export fn start(p: *process, c: *command) void = {
 	let pid: i32 = os.fork();
 	if (pid < 0) {
 		fail(p, pid);
+		closefd(&p.result, infd);
 		closefd(&p.result, outfd);
 		closefd(&p.result, errfd);
 		closefd(&p.result, marker[0]);
 		closefd(&p.result, marker[1]);
 		return;
 	};
-	if (pid == 0) { child(c, av, ep, outfd, errfd, marker[0], marker[1]); };
+	if (pid == 0) {
+		child(c, av, ep, infd, outfd, errfd, marker[0], marker[1]);
+	};
 	p.pid = pid;
 	p.state = state.RUNNING as i32;
 	p.markerfd = marker[0];
+	closefd(&p.result, infd);
 	closefd(&p.result, outfd);
 	closefd(&p.result, errfd);
 	closefd(&p.result, marker[1]);