Work around ftruncate implementations that don't support extending
files.
diff --git a/server/file.c b/server/file.c
index 67805c2..32c2487 100644
--- a/server/file.c
+++ b/server/file.c
@@ -456,29 +456,46 @@
return 1;
}
-static int truncate_file( handle_t handle )
+/* extend a file beyond the current end of file */
+static int extend_file( struct file *file, off_t size )
{
- struct file *file;
- off_t result;
+ static const char zero;
- if (!(file = get_file_obj( current->process, handle, GENERIC_WRITE )))
- return 0;
- if (((result = lseek( file->obj.fd, 0, SEEK_CUR )) == -1) ||
- (ftruncate( file->obj.fd, result ) == -1))
+ /* extend the file one byte beyond the requested size and then truncate it */
+ /* this should work around ftruncate implementations that can't extend files */
+ if ((lseek( file->obj.fd, size, SEEK_SET ) != -1) &&
+ (write( file->obj.fd, &zero, 1 ) != -1))
{
- file_set_error();
- release_object( file );
- return 0;
+ ftruncate( file->obj.fd, size );
+ return 1;
}
- release_object( file );
- return 1;
+ file_set_error();
+ return 0;
+}
+
+/* truncate file at current position */
+static int truncate_file( struct file *file )
+{
+ int ret = 0;
+ off_t pos = lseek( file->obj.fd, 0, SEEK_CUR );
+ off_t eof = lseek( file->obj.fd, 0, SEEK_END );
+
+ if (eof < pos) ret = extend_file( file, pos );
+ else
+ {
+ if (ftruncate( file->obj.fd, pos ) != -1) ret = 1;
+ else file_set_error();
+ }
+ lseek( file->obj.fd, pos, SEEK_SET ); /* restore file pos */
+ return ret;
}
/* try to grow the file to the specified size */
int grow_file( struct file *file, int size_high, int size_low )
{
+ int ret = 0;
struct stat st;
- off_t size = size_low + (((off_t)size_high)<<32);
+ off_t old_pos, size = size_low + (((off_t)size_high)<<32);
if (fstat( file->obj.fd, &st ) == -1)
{
@@ -486,9 +503,10 @@
return 0;
}
if (st.st_size >= size) return 1; /* already large enough */
- if (ftruncate( file->obj.fd, size ) != -1) return 1;
- file_set_error();
- return 0;
+ old_pos = lseek( file->obj.fd, 0, SEEK_CUR ); /* save old pos */
+ ret = extend_file( file, size );
+ lseek( file->obj.fd, old_pos, SEEK_SET ); /* restore file pos */
+ return ret;
}
static int set_file_time( handle_t handle, time_t access_time, time_t write_time )
@@ -604,7 +622,13 @@
/* truncate (or extend) a file */
DECL_HANDLER(truncate_file)
{
- truncate_file( req->handle );
+ struct file *file;
+
+ if ((file = get_file_obj( current->process, req->handle, GENERIC_WRITE )))
+ {
+ truncate_file( file );
+ release_object( file );
+ }
}
/* flush a file buffers */
