[Libsysio-commit] HEAD: libsysio/src truncate.c

[Lee W. <lw...@us...>]

Update of /cvsroot/libsysio/libsysio/src
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv6661/src

Modified Files:
	truncate.c 
Log Message:


Add a new macro, F_CHKRW, that given a pointer to an open file table entry
and one of 'r' or 'w' will return:

	0	if the access is permitted against the open file
	-EBADF	if not opened for the desired access
	-EROFS	if 'w' and the file system was mounted read-only

Then, using the new macro, implemented a check for the truncate/ftruncate
calls to assure the file and mount will permit the operation before
attempting it against the lower-level driver.


Index: truncate.c
===================================================================
RCS file: /cvsroot/libsysio/libsysio/src/truncate.c,v
retrieving revision 1.13
retrieving revision 1.14
diff -u -w -b -B -p -r1.13 -r1.14
--- truncate.c	21 Sep 2004 16:18:31 -0000	1.13
+++ truncate.c	10 Apr 2006 23:25:54 -0000	1.14
@@ -43,6 +43,7 @@
 
 #include <unistd.h>
 #include <string.h>
+#include <fcntl.h>
 #include <errno.h>
 #include <assert.h>
 #include <sys/types.h>
@@ -52,6 +53,8 @@
 #include "sysio.h"
 #include "inode.h"
 #include "file.h"
+#include "fs.h"
+#include "mount.h"
 
 #include "sysio-symbols.h"
 
@@ -133,6 +136,9 @@ PREPEND(_, SYSIO_INTERFACE_NAME(ftruncat
 		err = -EBADF;
 		goto out;
 	}
+	err = F_CHKRW(fil, 'w');
+	if (err)
+		goto out;
 	err = do_truncate(NULL, fil->f_ino, length);
 out:
 	SYSIO_INTERFACE_RETURN(err ? -1 : 0, err);