added some useless shell commands

programs/rocksh/main.c

@@ -1,13 +1,46 @@
 #include <unistd.h>
 #include <stdio.h>
+#include <string.h>
 
 const char* shell_prompt = "rocksh> ";
 
+char buf[256];
+size_t buf_offset = 0;
+
+void parse_cmd() {
+    if (strcmp(buf, "exit") == 0) {
+        printf("bye!\n");
+        exit(0);
+    }
+
+    if (strcmp(buf, "motd")  == 0) {
+        printf("rockos is the best!\n");
+    }
+}
+
+void reset() {
+    memset(buf, 0, 256);
+    buf_offset = 0;
+}
+
 int main(int argc, char *argv[]) {
     (void)argc;
     (void)argv;
 
     printf(shell_prompt);
+    while (1) {
+        char c;
+        int rd = read(0, &c, 1);
+        if (rd > 0) {
+            if (c == '\n') {
+                parse_cmd();
+                reset();
+                printf(shell_prompt);
+                continue;
+            }
+            buf[buf_offset++] = c;
+        }
+    }
 
     return 0;
 }

programs/vga_text_term/main.c

@@ -1,5 +1,8 @@
 #include <unistd.h>
 
+#define VGA_TEXT_W 80
+#define VGA_TEXT_H 25
+
 void term();
 
 int ptys;
@@ -30,15 +33,37 @@ int main(int argc, char *argv[]) {
     return 0;
 }
 
+void clear(int fd) {
+    lseek(fd, 0, 0);
+    size_t bytes = VGA_TEXT_W * VGA_TEXT_H;
+    char c = ' ';
+    for (size_t i = 0; i < bytes; i++) {
+        write(fd, &c, 1);
+    }
+    lseek(fd, 0, 0);
+}
+
 void term() {
     int vga_fd = open("/dev/tvga");
     if (vga_fd == -1) return;
 
+    int kbd_fd = open("/dev/kbd");
+    if (kbd_fd == -1) return;
+
+    clear(vga_fd);
+
+    char c;
     while (1) {
-        char c;
+        // first, get shell output
         int rd = read(0, &c, 1);
         if (rd > 0) {
             write(vga_fd, &c, 1);
         }
+
+        // then read a byte from the kbd. If we got one, pass it to the shell
+        rd = read(kbd_fd, &c, 1);
+        if (rd > 0) {
+            write(1, &c, 1);
+        }
     }
 }