server/pipe.c

   1 /*
   2  * Server-side pipe management
   3  *
   4  * Copyright (C) 1998 Alexandre Julliard
   5  */
   6
   7 #include <assert.h>
   8 #include <fcntl.h>
   9 #include <string.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <sys/errno.h>
  13 #include <sys/stat.h>
  14 #include <sys/time.h>
  15 #include <sys/types.h>
  16 #include <time.h>
  17 #include <unistd.h>
  18
  19 #include "winerror.h"
  20 #include "winbase.h"
  21 #include "server/thread.h"
  22
  23 enum side { READ_SIDE, WRITE_SIDE };
  24
  25 struct pipe
  26 {
  27     struct object obj;             /* object header */
  28     struct pipe  *other;           /* the pipe other end */
  29     int           fd;              /* Unix file descriptor */
  30     enum side     side;            /* which side of the pipe is this */
  31 };
  32
  33 static void pipe_dump( struct object *obj, int verbose );
  34 static int pipe_add_queue( struct object *obj, struct wait_queue_entry *entry );
  35 static void pipe_remove_queue( struct object *obj, struct wait_queue_entry *entry );
  36 static int pipe_signaled( struct object *obj, struct thread *thread );
  37 static int pipe_get_read_fd( struct object *obj );
  38 static int pipe_get_write_fd( struct object *obj );
  39 static int pipe_get_info( struct object *obj, struct get_file_info_reply *reply );
  40 static void pipe_destroy( struct object *obj );
  41
  42 static const struct object_ops pipe_ops =
  43 {
  44     pipe_dump,
  45     pipe_add_queue,
  46     pipe_remove_queue,
  47     pipe_signaled,
  48     no_satisfied,
  49     pipe_get_read_fd,
  50     pipe_get_write_fd,
  51     no_flush,
  52     pipe_get_info,
  53     pipe_destroy
  54 };
  55
  56 static const struct select_ops select_ops =
  57 {
  58     default_select_event,
  59     NULL   /* we never set a timeout on a pipe */
  60 };
  61
  62 int create_pipe( struct object *obj[2] )
  63 {
  64     struct pipe *newpipe[2];
  65     int fd[2];
  66
  67     if (pipe( fd ) == -1)
  68     {
  69         file_set_error();
  70         return 0;
  71     }
  72     if (!(newpipe[0] = mem_alloc( sizeof(struct pipe) )))
  73     {
  74         close( fd[0] );
  75         close( fd[1] );
  76         return 0;
  77     }
  78     if (!(newpipe[1] = mem_alloc( sizeof(struct pipe) )))
  79     {
  80         close( fd[0] );
  81         close( fd[1] );
  82         free( newpipe[0] );
  83         return 0;
  84     }
  85     init_object( &newpipe[0]->obj, &pipe_ops, NULL );
  86     init_object( &newpipe[1]->obj, &pipe_ops, NULL );
  87     newpipe[0]->fd    = fd[0];
  88     newpipe[0]->other = newpipe[1];
  89     newpipe[0]->side  = READ_SIDE;
  90     newpipe[1]->fd    = fd[1];
  91     newpipe[1]->other = newpipe[0];
  92     newpipe[1]->side  = WRITE_SIDE;
  93     obj[0] = &newpipe[0]->obj;
  94     obj[1] = &newpipe[1]->obj;
  95     CLEAR_ERROR();
  96     return 1;
  97 }
  98
  99 static void pipe_dump( struct object *obj, int verbose )
 100 {
 101     struct pipe *pipe = (struct pipe *)obj;
 102     assert( obj->ops == &pipe_ops );
 103     fprintf( stderr, "Pipe %s-side fd=%d\n",
 104              (pipe->side == READ_SIDE) ? "read" : "write", pipe->fd );
 105 }
 106
 107 static int pipe_add_queue( struct object *obj, struct wait_queue_entry *entry )
 108 {
 109     struct pipe *pipe = (struct pipe *)obj;
 110     assert( obj->ops == &pipe_ops );
 111     if (!obj->head)  /* first on the queue */
 112     {
 113         if (!add_select_user( pipe->fd,
 114                               (pipe->side == READ_SIDE) ? READ_EVENT : WRITE_EVENT,
 115                               &select_ops, pipe ))
 116         {
 117             SET_ERROR( ERROR_OUTOFMEMORY );
 118             return 0;
 119         }
 120     }
 121     add_queue( obj, entry );
 122     return 1;
 123 }
 124
 125 static void pipe_remove_queue( struct object *obj, struct wait_queue_entry *entry )
 126 {
 127     struct pipe *pipe = (struct pipe *)grab_object(obj);
 128     assert( obj->ops == &pipe_ops );
 129
 130     remove_queue( obj, entry );
 131     if (!obj->head)  /* last on the queue is gone */
 132         remove_select_user( pipe->fd );
 133     release_object( obj );
 134 }
 135
 136 static int pipe_signaled( struct object *obj, struct thread *thread )
 137 {
 138     struct pipe *pipe = (struct pipe *)obj;
 139     struct timeval tv = { 0, 0 };
 140     fd_set fds;
 141
 142     assert( obj->ops == &pipe_ops );
 143     FD_ZERO( &fds );
 144     FD_SET( pipe->fd, &fds );
 145     if (pipe->side == READ_SIDE)
 146         return select( pipe->fd + 1, &fds, NULL, NULL, &tv ) > 0;
 147     else
 148         return select( pipe->fd + 1, NULL, &fds, NULL, &tv ) > 0;
 149 }
 150
 151 static int pipe_get_read_fd( struct object *obj )
 152 {
 153     struct pipe *pipe = (struct pipe *)obj;
 154     assert( obj->ops == &pipe_ops );
 155
 156     if (!pipe->other)
 157     {
 158         SET_ERROR( ERROR_BROKEN_PIPE );
 159         return -1;
 160     }
 161     if (pipe->side != READ_SIDE)  /* FIXME: should not be necessary */
 162     {
 163         SET_ERROR( ERROR_ACCESS_DENIED );
 164         return -1;
 165     }
 166     return dup( pipe->fd );
 167 }
 168
 169 static int pipe_get_write_fd( struct object *obj )
 170 {
 171     struct pipe *pipe = (struct pipe *)obj;
 172     assert( obj->ops == &pipe_ops );
 173
 174     if (!pipe->other)
 175     {
 176         SET_ERROR( ERROR_BROKEN_PIPE );
 177         return -1;
 178     }
 179     if (pipe->side != WRITE_SIDE)  /* FIXME: should not be necessary */
 180     {
 181         SET_ERROR( ERROR_ACCESS_DENIED );
 182         return -1;
 183     }
 184     return dup( pipe->fd );
 185 }
 186
 187 static int pipe_get_info( struct object *obj, struct get_file_info_reply *reply )
 188 {
 189     memset( reply, 0, sizeof(*reply) );
 190     reply->type = FILE_TYPE_PIPE;
 191     return 1;
 192 }
 193
 194 static void pipe_destroy( struct object *obj )
 195 {
 196     struct pipe *pipe = (struct pipe *)obj;
 197     assert( obj->ops == &pipe_ops );
 198
 199     if (pipe->other) pipe->other->other = NULL;
 200     close( pipe->fd );
 201     free( pipe );
 202 }