execvp

Author: tbfleming

js/build-busybox

@@ -2,7 +2,7 @@
 mkdir -p bin
 
 export CFLAGS="-include `readlink -f runtime/em-shell.h` -g"
-export EM_LDFLAGS="--pre-js ../em-shell/js/pre.js --js-opts 0 `readlink -f runtime/em-shell.c`"
+export EM_LDFLAGS="--pre-js ../em-shell/js/pre.js --js-opts 0 `readlink -f runtime/em-shell.c` --js-library `readlink -f runtime/em-shell.js`"
 export KBUILD_VERBOSE=1
 export ARCH=em 
 export CROSS_COMPILE=em

js/console.js

@@ -76,10 +76,14 @@ function serviceConnected() {
 
     let messageChannel = new MessageChannel();
     messageChannel.port1.onmessage = e => {
-        term.write(e.data.replace('\n', '\r\n'));
+        if (e.data.command == 'writeConsole')
+            term.write(e.data.msg.replace('\n', '\r\n'));
+        else if(e.data.command == 'spawn') {
+            e.data.port.postMessage(9);
+        }
     };
     navigator.serviceWorker.controller.postMessage({
-        'command': 'consoleSetOutputPort',
+        'command': 'setMasterPort',
         'port': messageChannel.port2}, 
         [messageChannel.port2]);
 

js/service.js

@@ -4,7 +4,7 @@ let prefix = this.registration.scope + 'service/';
 let consoleInput = '';
 let consoleInputWaiting = [];
 let consoleOutput = '';
-let consoleOutputPort = null;
+let masterPort = null;
 
 console.log('starting');
 
@@ -18,41 +18,52 @@ this.addEventListener('fetch', function (e) {
 
     if (path === 'check')
         e.respondWith(new Response('connected'));
-    else if (path === 'readConsole') {
-        if (consoleInput.length) {
+    else if (path === 'readConsole') {
+        if (consoleInput.length) {
             e.respondWith(new Response(consoleInput));
-            consoleInput = '';
-        } else {
-            e.respondWith(new Promise(function (resolve, reject) {
-                consoleInputWaiting.push(resolve);
-            }));
-        }
-    } else if (path === 'writeConsole') {
+            consoleInput = '';
+        } else {
+            e.respondWith(new Promise(function (resolve, reject) {
+                consoleInputWaiting.push(resolve);
+            }));
+        }
+    } else if (path === 'writeConsole') {
         e.request.text().then(writeConsole);
-        e.respondWith(new Response(''));
-    }
+        e.respondWith(new Response(''));
+    } else if (path === 'spawn') {
+        e.respondWith(new Promise(function (resolve, reject) {
+            e.request.json().then(j => {
+                let messageChannel = new MessageChannel();
+                messageChannel.port1.onmessage = e => resolve(new Response(e.data));
+                j.command = path;
+                j.port = messageChannel.port2;
+                masterPort.postMessage(j, [messageChannel.port2]);
+            });
+        }));
+    } else
+        writeConsole('fetch ' + e.request.url + '\r\n');
 });
 
-self.addEventListener('message', function (e) {
+self.addEventListener('message', function (e) {
     if (!e.isTrusted)
         return;
-    if (e.data.command == 'consoleSetOutputPort') {
-        consoleOutputPort = e.data.port;
-        consoleOutputPort.postMessage(consoleOutput);
-        consoleOutput = '';
-    } else if (e.data.command == 'consoleKeyPress') {
-        if (consoleInputWaiting.length) {
-            for(let w of consoleInputWaiting)
-                w(new Response(e.data.consoleKeyPress));
-            consoleInputWaiting = [];
+    if (e.data.command == 'setMasterPort') {
+        masterPort = e.data.port;
+        masterPort.postMessage({ command: 'writeConsole', msg: consoleOutput });
+        consoleOutput = '';
+    } else if (e.data.command == 'consoleKeyPress') {
+        if (consoleInputWaiting.length) {
+            for(let w of consoleInputWaiting)
+                w(new Response(e.data.consoleKeyPress));
+            consoleInputWaiting = [];
         } else
-            consoleInput += e.data.consoleKeyPress;
-    }
+            consoleInput += e.data.consoleKeyPress;
+    }
 });
 
-function writeConsole(msg) {
-    if (consoleOutputPort)
-        consoleOutputPort.postMessage(msg);
+function writeConsole(msg) {
+    if (masterPort)
+        masterPort.postMessage({ command: 'writeConsole', msg: msg });
     else
-        consoleOutput += msg;
+        consoleOutput += msg;
 }

runtime/em-shell.c

@@ -1,25 +1,44 @@
 #include "em-shell.h"
+#include <emscripten.h>
+#include <errno.h>
+
+#undef _exit
 
 jmp_buf vfork_jump_buffer;
 static int vfork_child_active = 0;
 static int vfork_child_pid = 0;
 
+static int em_createPid() {
+    return 99; /* TODO: fetch new pid from service.js */
+}
+
 int em_vfork(int is_parent) {
     if (is_parent) {
         vfork_child_active = 0;
+        errno = 0;
         return vfork_child_pid;
     }
     else {
         vfork_child_active = 1;
-        vfork_child_pid = 99; /* TODO: fetch new pid from service.js */
+        vfork_child_pid = em_createPid();
         return 0;
     }
 }
 
-#undef _exit
 void em_vfork_exit(int status) {
     if (vfork_child_active)
-        longjmp(vfork_jump_buffer, 1); /* TODO: send status to service.js if exec...() wasn't called */
+        longjmp(vfork_jump_buffer, 1); /* TODO: send status to service.js */
     else
         _exit(status);
 }
+
+int js_spawn(const char *file, char *const argv[]);
+int em_execvp(const char *file, char *const argv[]) {
+    errno = js_spawn(file, argv);
+    if (errno)
+        return -1;
+    else if (vfork_child_active)
+        longjmp(vfork_jump_buffer, 1);
+    else
+        _exit(0); /* TODO: bypass sending status to service.js */
+}

runtime/em-shell.h

@@ -4,7 +4,9 @@
 extern jmp_buf vfork_jump_buffer;
 int em_vfork(int is_parent);
 void em_vfork_exit(int status);
+int em_execvp(const char *file, char *const argv[]);
 
 #define vfork() (em_vfork(setjmp(vfork_jump_buffer)))
 #define _exit(status) (em_vfork_exit(status))
 #define _Exit(status) (em_vfork_exit(status))
+#define execvp(file, argv) (em_execvp((file), (argv)))

runtime/em-shell.js

@@ -0,0 +1,26 @@
+mergeInto(LibraryManager.library, {
+    // TODO: send pid
+    // TODO: send environment
+    // TODO: send open file handles
+    js_spawn: function (file, argv) {
+        'use strict';
+        file = Pointer_stringify(file);
+        var args = [];
+        while (true) {
+            var arg = getValue(argv, '*');
+            if (arg === 0)
+                break;
+            args.push(Pointer_stringify(arg));
+            argv += 4;
+        }
+
+        var req = new XMLHttpRequest();
+        req.open("POST", 'service/spawn', false);
+        req.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
+        req.send(JSON.stringify({ file: file, args: args }));
+        if (req.status === 200) {
+            return req.responseText | 0;
+        } else
+            return ERRNO_CODES.ENOMEM;
+    }
+});