source: trunk/kernel/syscalls/sys_mmap.c @ 6

/*
 * kern/sys_mmap.c - map files, memory or devices into process's 
 *                   virtual address space
 * 
 * Copyright (c) 2008,2009,2010,2011,2012 Ghassan Almaless
 * Copyright (c) 2011,2012 UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-kernel.
 *
 * ALMOS-kernel is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2.0 of the License.
 *
 * ALMOS-kernel is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ALMOS-kernel; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <errno.h>
#include <thread.h>
#include <vfs.h>
#include <sys-vfs.h>
#include <process.h>
#include <vmm.h>

///////////////////////////////////
int sys_mmap( mmap_attr_t * mattr )
{
        error_t err;
        uint_t count;
        struct thread_s *this;
        struct process_s *process;
        struct vfs_file_s *file;
        mmap_attr_t attr;
        size_t isize;
        int retval;
 
        this = current_thread;
        process = this->process;
        err  = EINVAL;
        file = NULL;

        if((err = cpu_copy_from_uspace(&attr, mattr, sizeof(mmap_attr_t))))
        {
                printk(INFO, "%s: failed, copying from uspace @%x\n",
                       __FUNCTION__, 
                       mattr);

                this->info.errno = EFAULT;
                return (int)VM_FAILED;
        }

        if((attr.flags  & VM_REG_HEAP)                     ||
           ((attr.flags & VM_REG_PVSH) == VM_REG_PVSH)     || 
           ((attr.flags & VM_REG_PVSH) == 0)               ||
           (attr.length == 0)                              ||
           (attr.offset & PMM_PAGE_MASK)                   || 
           ((attr.addr != NULL) && (((uint_t)attr.addr & PMM_PAGE_MASK)          ||
                                (NOT_IN_USPACE(attr.length + (uint_t)attr.addr)) ||
                                (NOT_IN_USPACE((uint_t)attr.addr)) )))
        {
                printk(INFO, "%s: failed, we don't like flags (%x), length (%d), or addr (%x)\n",
                       __FUNCTION__, 
                       attr.flags, 
                       attr.length, 
                       attr.addr);
     
                this->info.errno = EINVAL;
                return (int)VM_FAILED;
        }
   
        if(attr.flags & VM_REG_ANON)
        {
                attr.offset = 0;
                attr.addr   = (attr.flags & VM_REG_FIXED) ? attr.addr : NULL;
        }
        else
        {      
                /* FIXEME: possible concurent delete of file from another bugy thread closing it */
                if((attr.fd >= CONFIG_TASK_FILE_MAX_NR) || (process_fd_lookup(process, attr.fd, &file)))
                {
                        printk(INFO, "%s: failed, bad file descriptor (%d)\n", 
                               __FUNCTION__, 
                               attr.fd);

                        this->info.errno = EBADFD;
                        return (int)VM_FAILED;
                }
     
                //atomic_add(&file->f_count, 1);
                vfs_file_up(file);//FIXME coalsce access to remote node info
     
                //FIXME: does we really to get the size...
                isize = vfs_inode_size_get_remote(file->f_inode.ptr, file->f_inode.cid);
                if((attr.offset + attr.length) > isize)
                {
                        printk(INFO, "%s: failed, offset (%d) + len (%d) >= file's size (%d)\n", 
                               __FUNCTION__, 
                               attr.offset, 
                               attr.length, 
                               isize);

                        this->info.errno = ERANGE;
                        goto SYS_MMAP_FILE_ERR;
                }

                if(((attr.prot & VM_REG_RD) && !(VFS_IS(file->f_flags, VFS_O_RDONLY)))   ||
                   ((attr.prot & VM_REG_WR) && !(VFS_IS(file->f_flags, VFS_O_WRONLY)))   ||
                   ((attr.prot & VM_REG_WR) && (VFS_IS(file->f_flags, VFS_O_APPEND))))//    ||
                        //(!(attr.prot & VM_REG_RD) && (attr.flags & VM_REG_PRIVATE)))
                {
                        printk(INFO, "%s: failed, EACCES prot (%x), f_flags (%x)\n", 
                               __FUNCTION__, 
                               attr.prot, 
                               file->f_flags);

                        this->info.errno = EACCES;
                        goto SYS_MMAP_FILE_ERR;
                }
        }

        retval = (int) vmm_mmap(process,
                                file,
                                attr.addr,
                                attr.length,
                                attr.prot,
                                attr.flags,
                                attr.offset);
   
        if((retval != (int)VM_FAILED) || (attr.flags & VM_REG_ANON))
                return retval;

SYS_MMAP_FILE_ERR:
        printk(INFO, "%s: Failed, Droping file count \n", 
               __FUNCTION__);
   
        vfs_close( file , &count );

        if(count == 1) process_fd_put( process , attr.fd );

        return (int)VM_FAILED;
}