Implement message handling in stdio process

diff --git a/include/corax/ipc.h b/include/corax/ipc.h
index 2c941a5229e0b9cb358217c6ffc0aa97f31bd1e7..4cc329191687f02e2b69c91fa8676f8aafb75deb 100644 (file)
--- a/include/corax/ipc.h
+++ b/include/corax/ipc.h
@@ -1,19 +1,41 @@
 #ifndef __CORAX_IPC_H
 #define __CORAX_IPC_H
 
-struct cxmsg {
-       u32_t cm_src;
-       u32_t cm_dst;
-       u32_t cm_len;
+#define CX_MSG_RETVAL 0
+#define CX_MSG_READ   1
+#define CX_MSG_WRITE  2
+#define CX_MSG_FLUSH  3
+
+struct cxmsg_data_stdio {
+       int  sio_fd;
+       char sio_data[];
+};
 
-       u32_t cm_type;
+struct cxmsg_hdr {
+       u32_t cxh_src;
+       u32_t cxh_dst;
+       u32_t cxh_len;
+       u32_t cxh_type;
+};
+
+struct cxmsg {
+       struct cxmsg_hdr cm_hdr;
 
        union {
+               int CM_retval;
+               struct cxmsg_data_stdio CM_stdio;
                u8_t  CM_data[CONFIG_IPC_MSGSIZE];
        } CM_dat;
 };
 
-#define cm_data CM_dat.CM_data
+#define cm_src    cm_hdr.cxh_src
+#define cm_dst    cm_hdr.cxh_dst
+#define cm_len    cm_hdr.cxh_len
+#define cm_type   cm_hdr.cxh_type
+
+#define cm_stdio  CM_dat.CM_stdio
+#define cm_retval CM_dat.CM_retval
+#define cm_data   CM_dat.CM_data
 
 #define PID_INIT  1
 #define PID_NET   10

diff --git a/kernel/core/stdio.c b/kernel/core/stdio.c
index 4af8b34e4b46c3f7439504bfe66bb302ac2b48c0..72c3c331261d1bc079197cf5b5b367b2e0b69071 100644 (file)
--- a/kernel/core/stdio.c
+++ b/kernel/core/stdio.c
@@ -1,8 +1,34 @@
 #include <config.h>
 #include <crxstd.h>
 #include <corax/errno.h>
+#include <stddef.h>
 
-extern int wait(int*);
+#define STDIN  0
+#define STDOUT 1
+#define STDERR 2
+
+static int stdio_read(int fd, char *dst, size_t dsize)
+{
+       return(-ENOSYS);
+}
+
+static int stdio_write(int fd, const char *src, const size_t slen)
+{
+       return(-ENOSYS);
+}
+
+static int stdio_flush(int fd)
+{
+       if(fd < STDIN) {
+               return(-EINVAL);
+       }
+
+       if(fd > STDERR) {
+               return(-EBADF);
+       }
+
+       return(0);
+}
 
 void _stdio(void)
 {
@@ -13,11 +39,55 @@ void _stdio(void)
                err = cxrecv(PID_ANY, &msg);
                err = 0;
 
+               /*
+                * The `cm_len' member includes the number of bytes consumed by the header
+                * of the message, so we need to substract offsetof(struct cxmsg, cm_data)
+                * to get the number of bytes that are supposed to be in the payload.
+                */
+
+               if((msg.cm_len - offsetof(struct cxmsg, cm_stdio.sio_data)) > msg.cm_len) {
+                       /* underflow - discard message */
+                       continue;
+               }
+
+               msg.cm_len -= offsetof(struct cxmsg, cm_stdio.sio_data);
+
+               if(msg.cm_len > (sizeof(msg.cm_data) - offsetof(struct cxmsg, cm_stdio.sio_data))) {
+                       /* message allegedly contains more data than possible - malicious input? */
+                       continue;
+               }
+
+               /* msg.cm_len now contains the number of bytes in sio_data */
+
                if(err > 0) {
-                       /* FIXME: Handle message */
+                       switch(msg.cm_type) {
+                       case CX_MSG_READ:
+                               err = stdio_read(msg.cm_stdio.sio_fd,
+                                                                msg.cm_stdio.sio_data,
+                                                                msg.cm_len);
+                               break;
+
+                       case CX_MSG_WRITE:
+                               err = stdio_write(msg.cm_stdio.sio_fd,
+                                                                 msg.cm_stdio.sio_data,
+                                                                 msg.cm_len);
+                               break;
+
+                       case CX_MSG_FLUSH:
+                               err = stdio_flush(msg.cm_stdio.sio_fd);
+                               break;
+
+                       default:
+                               /* malformed input? */
+                               err = -EINVAL;
+                               break;
+                       }
 
                        msg.cm_dst = msg.cm_src;
-                       msg.cm_type = -ENOSYS;
+                       msg.cm_type = CX_MSG_RETVAL;
+                       msg.cm_retval = err;
+                       msg.cm_len = sizeof(msg.cm_hdr) + sizeof(int);
+
                        cxsend(msg.cm_dst, &msg);
                }
        }