implement device_read for block devices.

3 files changed, 57 insertions, 8 deletions

diff --git a/libdde_linux26/lib/src/mach_glue/block.c b/libdde_linux26/lib/src/mach_glue/block.c
index a856cc9b..ea44d87f 100644
--- a/libdde_linux26/lib/src/mach_glue/block.c
+++ b/libdde_linux26/lib/src/mach_glue/block.c
@@ -20,8 +20,8 @@ struct block_device *open_block_dev (char *name, int part, fmode_t mode)
 /* write a piece of data to a block device.
  * DATA must be in one page.
  * SECTORNR: the writing location in sectors. */
-int block_dev_write (struct block_device *dev, int sectornr,
-		     char *data, int count, void (*write_done (int err)))
+int block_dev_rw (struct block_device *dev, int sectornr,
+		  char *data, int count, int rw, void (*write_done (int err)))
 {
   int err = 0;
   struct bio *bio;
@@ -63,7 +63,7 @@ int block_dev_write (struct block_device *dev, int sectornr,
   bio->bi_end_io = end_bio;
   bio->bi_private = NULL;
   bio_get (bio);
-  submit_bio (WRITE, bio);
+  submit_bio (rw, bio);
   if (bio_flagged (bio, BIO_EOPNOTSUPP))
     {
       err = -EOPNOTSUPP;
diff --git a/libmachdev/block.c b/libmachdev/block.c
index 48fe6cd6..2a4b9ae2 100644
--- a/libmachdev/block.c
+++ b/libmachdev/block.c
@@ -24,6 +24,7 @@
 #include <ctype.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <sys/mman.h>
 
 #include "mach_U.h"
 
@@ -40,6 +41,11 @@
 #include "util.h"
 #include "mach_glue.h"
 
+/* for submit_bio(). But it might not be very proper to keep
+ * my own definitions of these macros. */
+#define READ 0
+#define WRITE 1
+
 /* One of these is associated with each open instance of a device.  */
 struct block_data
 {
@@ -180,6 +186,7 @@ device_write (void *d, mach_port_t reply_port,
   void write_done (int err)
     {
       int len = err ? 0 : count;
+      // TODO maybe I should send the reply as long as there is an error.
       writes--;
       if (writes == 0)
 	{
@@ -200,7 +207,7 @@ device_write (void *d, mach_port_t reply_port,
       int size = PAGE_SIZE - ((int) data &~PAGE_MASK) > count ?
 	count : PAGE_SIZE - ((int) data &~PAGE_MASK);
 
-      err = block_dev_write (bd->dev, bn, data, size, write_done);
+      err = block_dev_rw (bd->dev, bn, data, size, WRITE, write_done);
       if (err)
 	break;
       bn += size >> 9;
@@ -220,11 +227,53 @@ device_read (void *d, mach_port_t reply_port,
 	     unsigned *bytes_read)
 {
   struct block_data *bd = d;
+  io_return_t err = D_SUCCESS;
+  int i;
+  int reads = 0;
+  char *buf;
+  int npages = (count + PAGE_SIZE - 1) / PAGE_SIZE;
+
+  void read_done (int err)
+    {
+      int len = err ? 0 : count;
+      reads--;
+      if (reads == 0)
+	{
+	  err = linux_to_mach_error (err);
+	  ds_device_read_reply (reply_port, reply_port_type, err, buf, len);
+	}
+    }
 
   if ((bd->mode & D_READ) == 0)
     return D_INVALID_OPERATION;
-  *bytes_read = 0;
-  return D_SUCCESS;
+
+  if (count == 0)
+    return 0;
+
+  *data = 0;
+  buf = mmap (NULL, npages * PAGE_SIZE, PROT_READ|PROT_WRITE,
+	      MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
+  if (buf == MAP_FAILED)
+    return errno;
+
+  ddekit_printf ("read %d pages.\n", npages);
+  for (i = 0; i < npages; i++)
+    {
+      int size = count > PAGE_SIZE ? PAGE_SIZE : count;
+      ddekit_printf ("read %d bytes starting from %d\n", size, bn);
+
+      err = block_dev_rw (bd->dev, bn, buf + i * PAGE_SIZE,
+			  size, READ, read_done);
+      if (err)
+	break;
+      bn += size >> 9;
+      count -= size;
+      reads++;
+    }
+  // TODO when should I deallocate the buffer?
+  if (reads)
+    return MIG_NO_REPLY;
+  return linux_to_mach_error (err);
 }
 
 static io_return_t
diff --git a/libmachdev/mach_glue.h b/libmachdev/mach_glue.h
index 770ea51b..7b122583 100644
--- a/libmachdev/mach_glue.h
+++ b/libmachdev/mach_glue.h
@@ -33,8 +33,8 @@ void skb_done_head_init();
 /* block device */
 struct block_device;
 struct block_device *open_block_dev (char *name, int part, dev_mode_t mode);
-int block_dev_write (struct block_device *dev, int sectornr,
-		     char *data, int count, void (*write_done) (int err));
+int block_dev_rw (struct block_device *dev, int sectornr,
+		  char *data, int count, int rw, void (*write_done) (int err));
 
 int l4dde26_process_from_ddekit(ddekit_thread_t *t);