In MINIX 3.2.1, I want to create a new system call in VFS server which will be given a filename as a parameter and will print this certain file's inode number.
So in order to retrieve the inode of the file by its name I want to use the default system call:
int stat(char *name,struct stat *buffer)
http://minix1.woodhull.com/manpages/man2/stat.2.html
in the body of my new system call handler which is
int mycall_1(void);
inside `/usr/src/servers/vfs/misc.c
But when I test the new system call, at the point where the stat system call should be invoked, it actually won't and instead it's printing the message:
sys_call: ipc mask denied SENDREC from 1 to 1
After some research, I found that this possibly happens because the VFS server tries to send a message to itself, as stat is actually implemented inside VFS server, and so ipc mask denied this sendrec() call. So I have to edit some configuration file in order to give the right permission for this communication to happen.
But I'm not sure if what I have understood is right and also do not know which file should Ι edit to give the appropriate permissions. So, if someone could enlighten me on this issue, I would be grateful.
Thanks in advance.
You understood it correctly. But the solution is not to continue "fixing the permissions" which are here just to prevent to shot yourself in the foot: it would only allow the system to more badly brocken.
Rather, you need to perform the steps that VFS do when it services a STAT request, starting after it cracked the message.