root/fs/pipefs/fifo.c

/* */

DEFINITIONS

1. fifo_open

   1 /*
   2  * fiwix/fs/pipefs/fifo.c
   3  *
   4  * Copyright 2018, Jordi Sanfeliu. All rights reserved.
   5  * Distributed under the terms of the Fiwix License.
   6  */
   7 
   8 #include <fiwix/types.h>
   9 #include <fiwix/errno.h>
  10 #include <fiwix/fs.h>
  11 #include <fiwix/filesystems.h>
  12 #include <fiwix/fs_pipe.h>
  13 #include <fiwix/stat.h>
  14 #include <fiwix/mm.h>
  15 #include <fiwix/sleep.h>
  16 #include <fiwix/fcntl.h>
  17 #include <fiwix/sched.h>
  18 #include <fiwix/stdio.h>
  19 
  20 int fifo_open(struct inode *i, struct fd *fd_table)
  21 {
  22         /* first open */
  23         if(i->count == 1) {
  24                 if(!(i->u.pipefs.i_data = (void *)kmalloc())) {
  25                         return -ENOMEM;
  26                 }
  27                 i->u.pipefs.i_readoff = 0;
  28                 i->u.pipefs.i_writeoff = 0;
  29         }
  30 
  31         if((fd_table->flags & O_ACCMODE) == O_RDONLY) {
  32                 i->u.pipefs.i_readers++;
  33                 wakeup(&pipefs_write);
  34                 if(!(fd_table->flags & O_NONBLOCK)) {
  35                         while(!i->u.pipefs.i_writers) {
  36                                 if(sleep(&pipefs_read, PROC_INTERRUPTIBLE)) {
  37                                         if(!--i->u.pipefs.i_readers) {
  38                                                 wakeup(&pipefs_write);
  39                                         }
  40                                         return -EINTR;
  41                                 }
  42                         }
  43                 }
  44         }
  45 
  46         if((fd_table->flags & O_ACCMODE) == O_WRONLY) {
  47                 if((fd_table->flags & O_NONBLOCK) && !i->u.pipefs.i_readers) {
  48                         return -ENXIO;
  49                 }
  50 
  51                 i->u.pipefs.i_writers++;
  52                 wakeup(&pipefs_read);
  53                 if(!(fd_table->flags & O_NONBLOCK)) {
  54                         while(!i->u.pipefs.i_readers) {
  55                                 if(sleep(&pipefs_write, PROC_INTERRUPTIBLE)) {
  56                                         if(!--i->u.pipefs.i_writers) {
  57                                                 wakeup(&pipefs_read);
  58                                         }
  59                                         return -EINTR;
  60                                 }
  61                         }
  62                 }
  63         }
  64 
  65         if((fd_table->flags & O_ACCMODE) == O_RDWR) {
  66                 i->u.pipefs.i_readers++;
  67                 i->u.pipefs.i_writers++;
  68                 wakeup(&pipefs_write);
  69                 wakeup(&pipefs_read);
  70         }
  71 
  72         return 0;
  73 }

/* */