Changeset 222e57c in mainline for uspace/srv/vfs/vfs_rdwr.c

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).

File:

• uspace/srv/vfs/vfs_rdwr.c (modified) (2 diffs)

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);
+}
+
 /**
  * @}