feat: file descriptor and proper stdio

1 files changed, 33 insertions, 0 deletions

diff --git a/user/chat.c b/user/chat.c
new file mode 100644
index 0000000..67bc727
--- /dev/null
+++ b/user/chat.c
@@ -0,0 +1,33 @@
+#include "user.h"
+
+void _start(const char* arg, unsigned long arglen)
+{
+    if (arglen == 0)
+    {
+        put("usage: run chat <path>\n");
+        sys_exit(1);
+    }
+
+    char path[128];
+    unsigned long i = 0;
+    for (; i < arglen && i < sizeof(path) - 1; i++)
+        path[i] = arg[i];
+    path[i] = 0;
+
+    long fd = sys_open(path, 0);
+    if (fd < 0)
+    {
+        put("chat: ");
+        put(path);
+        put(": cannot open\n");
+        sys_exit(1);
+    }
+
+    char buffer[256];
+    long n;
+    while ((n = sys_read(fd, buffer, sizeof(buffer))) > 0)
+        sys_write(1, buffer, (unsigned long)n);
+
+    sys_close(fd);
+    sys_exit(0);
+}