Changeset fa24efa in mainline

Timestamp:

2013-10-04T22:55:10Z (11 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

d65be39

Parents:

f1d04b2

Message:

make sure read() and write() respect DATA_XFER_LIMIT

Files:

• abi/include/abi/ipc/ipc.h (modified) (1 diff)
• kernel/generic/include/config.h (modified) (1 diff)
• uspace/lib/c/generic/vfs/vfs.c (modified) (3 diffs)

abi/include/abi/ipc/ipc.h

@@ -59 +59 @@
 /** Interrupt notification */
 #define IPC_CALL_NOTIF  (1 << 3)
+
+/**
+ * Maximum buffer size allowed for IPC_M_DATA_WRITE and
+ * IPC_M_DATA_READ requests.
+ */
+#define DATA_XFER_LIMIT  (64 * 1024)
 
 

kernel/generic/include/config.h

@@ -47 +47 @@
 #define CONFIG_TASK_NAME_BUFLEN  32
 #define CONFIG_TASK_ARGUMENTS_BUFLEN 64
-
-/**
- * Maximum buffer size allowed for IPC_M_DATA_WRITE and IPC_M_DATA_READ
- * requests.
- */
-#define DATA_XFER_LIMIT  (64 * 1024)
 
 #ifndef __ASM__

uspace/lib/c/generic/vfs/vfs.c

@@ -342 +342 @@
 }
 
-ssize_t read(int fildes, void *buf, size_t nbyte) 
+ssize_t read(int fildes, void *buf, size_t nbyte)
 {
         sysarg_t rc;
@@ -348 +348 @@
         aid_t req;
         
+        if (nbyte > DATA_XFER_LIMIT)
+                nbyte = DATA_XFER_LIMIT;
+        
         async_exch_t *exch = vfs_exchange_begin();
         
         req = async_send_1(exch, VFS_IN_READ, fildes, &answer);
-        rc = async_data_read_start(exch, (void *)buf, nbyte);
+        rc = async_data_read_start(exch, (void *) buf, nbyte);
         if (rc != EOK) {
                 vfs_exchange_end(exch);
@@ -377 +380 @@
         aid_t req;
         
+        if (nbyte > DATA_XFER_LIMIT)
+                nbyte = DATA_XFER_LIMIT;
+        
         async_exch_t *exch = vfs_exchange_begin();
         
         req = async_send_1(exch, VFS_IN_WRITE, fildes, &answer);
-        rc = async_data_write_start(exch, (void *)buf, nbyte);
+        rc = async_data_write_start(exch, (void *) buf, nbyte);
         if (rc != EOK) {
                 vfs_exchange_end(exch);