Changeset 222e57c in mainline

Timestamp:

2008-01-06T19:39:13Z (17 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

41a0d27

Parents:

10d6b858

Message:

Add libc and VFS implementation of lseek(), VFS_SEEK resp.
Add the size member to the VFS node structure (not yet initialized).

Files:

• kernel/generic/include/errno.h (modified) (1 diff)
• uspace/lib/libc/generic/vfs.c (modified) (2 diffs)
• uspace/lib/libc/include/unistd.h (modified) (1 diff)
• uspace/srv/vfs/vfs.c (modified) (1 diff)
• uspace/srv/vfs/vfs.h (modified) (2 diffs)
• uspace/srv/vfs/vfs_rdwr.c (modified) (2 diffs)

kernel/generic/include/errno.h

@@ -56 +56 @@
 #define EINVAL          -13     /* Invalid value */
 #define EBUSY           -14     /* Resource is busy */
+#define EOVERFLOW       -15     /* The result does not fit its size. */
 
 #endif

uspace/lib/libc/generic/vfs.c

@@ -1 +1 @@
 /*
- * Copyright (c) 2007 Jakub Jermar 
+ * Copyright (c) 2008 Jakub Jermar 
  * All rights reserved.
  *
@@ -185 +185 @@
         return (ssize_t) IPC_GET_ARG1(answer);
 }
+
+off_t lseek(int fildes, off_t offset, int whence)
+{
+        int res;
+        ipcarg_t rc;
+
+        futex_down(&vfs_phone_futex);
+        async_serialize_start();
+        if (vfs_phone < 0) {
+                res = vfs_connect();
+                if (res < 0) {
+                        async_serialize_end();
+                        futex_up(&vfs_phone_futex);
+                        return res;
+                }
+        }
+                
+        off_t newoffs;
+        rc = async_req_3_1(vfs_phone, VFS_SEEK, fildes, offset, whence,
+            &newoffs);
+
+        async_serialize_end();
+        futex_up(&vfs_phone_futex);
+
+        if (rc != EOK)
+                return (off_t) -1;
+        
+        return newoffs;
+}
+
 /** @}
  */

uspace/lib/libc/include/unistd.h

@@ -42 +42 @@
 #define getpagesize()     (PAGE_SIZE)
 
+#define SEEK_SET        0
+#define SEEK_CUR        1
+#define SEEK_END        2
+
 extern ssize_t write(int fd, const void * buf, size_t count);
 extern ssize_t read(int fd, void * buf, size_t count);
+extern off_t lseek(int, off_t, int);
+
 extern void _exit(int status);
 extern void *sbrk(ssize_t incr);

uspace/srv/vfs/vfs.c

@@ -100 +100 @@
                         vfs_write(callid, &call);
                         break;
+                case VFS_SEEK:
+                        vfs_seek(callid, &call);
+                        break;
                 case VFS_UNMOUNT:
                 case VFS_CREATE:
                 case VFS_CLOSE:
-                case VFS_SEEK:
                 case VFS_UNLINK:
                 case VFS_RENAME:

uspace/srv/vfs/vfs.h

@@ -136 +136 @@
         unsigned refcnt;        /**< Usage counter. */
         link_t nh_link;         /**< Node hash-table link. */
+        size_t size;            /**< Cached size of the file. */
 
         /**
@@ -211 +212 @@
 extern void vfs_read(ipc_callid_t, ipc_call_t *);
 extern void vfs_write(ipc_callid_t, ipc_call_t *);
+extern void vfs_seek(ipc_callid_t, ipc_call_t *);
 
 #endif

uspace/srv/vfs/vfs_rdwr.c

@@ -41 +41 @@
 #include <errno.h>
 #include <rwlock.h>
+#include <unistd.h>
 
 static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)
@@ -156 +157 @@
 }
 
+void vfs_seek(ipc_callid_t rid, ipc_call_t *request)
+{
+        int fd = (int) IPC_GET_ARG1(*request);
+        off_t off = (off_t) IPC_GET_ARG2(*request);
+        int whence = (int) IPC_GET_ARG3(*request);
+
+
+        /*
+         * Lookup the file structure corresponding to the file descriptor.
+         */
+        vfs_file_t *file = vfs_file_get(fd);
+        if (!file) {
+                ipc_answer_0(rid, ENOENT);
+                return;
+        }
+
+        off_t newpos;
+        futex_down(&file->lock);
+        if (whence == SEEK_SET) {
+                file->pos = off;
+                futex_up(&file->lock);
+                ipc_answer_1(rid, EOK, off);
+                return;
+        }
+        if (whence == SEEK_CUR) {
+                if (file->pos + off < file->pos) {
+                        futex_up(&file->lock);
+                        ipc_answer_0(rid, EOVERFLOW);
+                        return;
+                }
+                file->pos += off;
+                newpos = file->pos;
+                futex_up(&file->lock);
+                ipc_answer_1(rid, EOK, newpos);
+                return;
+        }
+        if (whence == SEEK_END) {
+                rwlock_reader_lock(&file->node->contents_rwlock);
+                size_t size = file->node->size;
+                rwlock_reader_unlock(&file->node->contents_rwlock);
+                if (size + off < size) {
+                        futex_up(&file->lock);
+                        ipc_answer_0(rid, EOVERFLOW);
+                        return;
+                }
+                newpos = size + off;
+                futex_up(&file->lock);
+                ipc_answer_1(rid, EOK, newpos);
+                return;
+        }
+        futex_up(&file->lock);
+        ipc_answer_0(rid, EINVAL);
+}
+
 /**
  * @}